Some of the last surviving Neanderthals displayed greater genetic diversity than scientists previously thought, a new study of ancient DNA reveals, challenging the idea that genetic decline was the main cause of their extinction.

Neanderthals were among the closest relatives of modern humans, with their lineages diverging around 500,000 years ago. Although Neanderthals once ranged across Eurasia, they are usually thought to have gone extinct about 40,000 years ago.

Much remains a mystery about why Neanderthals went extinct. Previous genetic analyses of DNA from Neanderthals in Siberia revealed that those groups lived in small, isolated communities with signs of frequent interbreeding between close relatives. This raised the possibility that Neanderthals might have died off due to genetic deterioration from inbreeding.

However, DNA from Neanderthals is rare, and high-quality genomes are especially uncommon; until the new study, only four were available, three of which came from Russia, at the edge of the Neanderthals' geographic range. As such, it was uncertain whether DNA analyses of just a few Neanderthals accurately reflected why the entire lineage went extinct.

In the new study, published Wednesday (June 24) in the journal Nature, scientists recovered genetic data from 27 more Neanderthals, including a new high-quality genome, one with enough DNA for scientists to analyze many times to ensure the accuracy of their results.

"Some people might think the retrieval of ancient DNA from Neanderthals is now conventional; the truth is that this is far from trivial," Carles Lalueza-Fox, director of the Natural Sciences Museum of Barcelona in Spain, who did not take part in this research, told Live Science. Adding 27 more Neanderthals "to our general knowledge is a remarkable achievement."

The new data comes from 10 archaeological sites in northwestern Europe, in present-day Belgium and France. Seven of these sites were located in the Meuse Basin in Belgium, an area with a high concentration of late Neanderthals — those who lived after about 70,000 years ago. One of these sites was the Goyet cave system in Belgium, which recent findings suggested may hold evidence of Neanderthal cannibalism.

The genetic analysis revealed the late Neanderthals of northwestern Europe separated from a common ancestor with other known Neanderthals about 54,000 years ago. The newly studied late Neanderthals were more closely related to one another than late Neanderthal groups in other parts of Europe.

The scientists discovered that unlike other Neanderthal groups, many of the Neanderthals they examined showed little evidence of inbreeding. In addition, the new high-quality Neanderthal genome did not show lower genetic diversity than earlier Neanderthals. This finding suggests that reduced genetic diversity may not have been the primary reason Neanderthals died off.

"I am very happy to dispel the misconception that all Neandertals went extinct because they were too inbred," Alba Bossoms Mesa, a doctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Germany and first author of the study, told Live Science.

The study also revealed that the late Neanderthals of northwestern Europe that they analyzed were a large population of genetically interconnected groups, rather than the genetically isolated communities seen among Siberian Neanderthals.

"Neanderthals lived across vast regions of Eurasia over hundreds of thousands of years, so of course there is a lot of variation between them," Bossoms Mesa said. "It's not good to generalize about Neanderthals. We have to keep diversity in mind."

In addition, the newly analyzed late Neanderthals of northwestern Europe displayed a significant level of genetic diversity, dividing into at least four distinct groups, the researchers found. The splits between these groups appeared to originate during relatively warm spans of climate, perhaps reflecting times of population expansion during periods of favorable environmental conditions, the team noted.

Striking asymmetry

The late Neanderthals of northwestern Europe were contemporaries of modern humans (Homo sapiens) in Europe for up to 500 generations, the researchers said. Previous research has discovered Neanderthal DNA in modern-human genomes, revealing these lineages had mingled, with most modern-day humans outside Africa possessing some Neanderthal DNA. However, the new study found no evidence of recent modern-human DNA in these Neanderthals of Belgium and France, suggesting the two groups didn't mate there.

The new findings add to a striking asymmetry seen between Neanderthals and modern humans. "We have several examples of early modern humans who had a Neandertal ancestor only a few generations back," Bossoms Mesa said. "But in contrast, we do not yet have a single confirmed example of a Neanderthal individual with a recent modern human ancestor in their family tree."

There are several possible reasons for this asymmetry, Lalueza-Fox said. For instance, maybe there were genetic problems that prevented H. sapiens DNA from integrating with the Neanderthal gene pool. For instance, a 2025 study suggested that different versions of a gene tied to red blood cell function might have caused Neanderthal-human hybrid women to miscarry their fetuses.

However, "in my view, this conspicuous bias likely reflects a pattern of differential social acceptance among Neanderthals," he noted. "In brief, early modern humans were able to accept kids with Neanderthals but not the opposite, for whatever reason. This pattern, coupled with declining diversity in some Neanderthal populations, could explain their final extinction."

Future research can see if Neanderthals at other sites, such as the Iberian or Italian peninsulas, displayed similar levels of genetic diversity, Bossoms Mesa said. However, analyzing samples from these latter areas "is currently a bit more challenging, because ancient DNA preserves better in colder areas," she noted.

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Around 60,000 years ago in Siberia, a Neanderthal opened their mouth so that a rotten tooth could be drilled — and the case is the oldest evidence of an intentional dental treatment to date, a new study finds.

A lower molar tooth belonging to a Neanderthal adult was originally unearthed in 2016, but it was not clear what had caused the deep hole in its surface. Now, experimental evidence indicates the hole was made with a small stone drill used to clean out bits of severely rotten tooth tissue, according to a study published Wednesday (May 13) in the journal PLOS One.

This intricate procedure shows Neanderthals — our closest human relatives who lived from around 400,000 to 40,000 years ago — had the brains to recognize this painful tooth cavity could be treated and possessed the fine motor skills to successfully execute the procedure.

"The fact that this invasive treatment took place and the person survived lends me to believe that this is another example of the really very sophisticated Neanderthal understanding of human biology and when you need to intervene," study co-author John W. Olsen, a professor emeritus of anthropology at the University of Arizona, told Live Science.

It's unclear whether this was self-treatment or dentistry performed by another individual. Even so, "it suggests that the roots of invasive medicine and surgery do not belong exclusively to Homo sapiens, but are part of a broader legacy shared with our closest relatives," Gregorio Oxilia, an associate professor of human anatomy at the Free Mediterranean University in Italy who was not involved in the research, told Live Science in an email.

The oldest evidence of our own species, Homo sapiens, treating tooth decay dates to roughly 14,000 years ago in what is now Italy. By pushing back the date of intentional dentistry by roughly 45,000 years, this new finding "fundamentally reshapes our understanding of the evolution of human healthcare," said Oxilia, who was the first author on the study detailing the 14,000-year-old finding.

Prehistoric healthcare

There are now multiple known cases of Neanderthal healthcare. For example, different sites in Spain show that Neanderthals seem to have cared for a child with Down syndrome and ate medicinal plants.

However, in part because their generally low-carbohydrate diets kept the rates of tooth decay low, evidence of dental interventions in Neanderthals has been limited.

So, to determine whether the unusual hole in the roughly 59,000-year-old Neanderthal molar found in Chagyrskaya Cave was deliberately human-made, the researchers inspected the tooth and ran experiments using three modern human teeth.

Microscopic analyses of the Neanderthal molar revealed two patches of deep demineralization, indicative of severe tooth decay. One area of tooth decay was located where the tooth would have met the gumline. Here, the researchers identified straight grooves characteristic of tooth picking.

The other decayed patch overlapped with the 0.17 inch long, 0.11 inch wide and 0.10 inch deep (4.2 mm long, 2.8 mm wide and 2.6 mm deep) cavity on the tooth's surface. There were tiny markings along the top edge of this hole.

The team then ran experiments on three modern human teeth to see which tools and motions were required to replicate these markings. This revealed the grooves could be made by the twisting motion of small stone tools made from locally available jasper. Multiple examples of tools with long, thin, pointed tips that could have served this purpose have previously been found in Chagyrskaya Cave.

Evidence of chew marks overlaying the grooves around the cavity indicates this individual "not only survived the operation," Olsen said, "but that they lived for some significant period of time, allowing their normal chewing activities to begin to erase the evidence of the original drilling."

While scientists cannot be certain the hole was made using a stone dental drill, the very localized markings make this conclusion more likely than other possible explanations, such as the hole being the result of damage after the individual died, said Marina Lozano Ruiz, a bioarchaeologist who researches Neanderthal teeth at the University of Rovira i Virgili in Catalonia, who was not involved in the study.

The case is "exceptional precisely because it shows that they were able to react to an uncommon pathology with a highly targeted and technically complex response," Oxilia said.

Rebecca Wragg Sykes, an archaeologist at the University of Cambridge and author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury Sigma, 2020), thinks the procedure was likely self-treatment. "Digging into this rotten tooth probably didn't need anyone to help," Sykes, who was not involved in the study, told Live Science in an email.

Although group members may have provided emotional support during the painful procedure, "we've learned from other primates that they can actually survive really serious conditions without any help from their group," she said.

Editor's note: This story was updated at 9:33 a.m. ET on May 14 to update Gregorio Oxilia's title to associate professor of human anatomy.

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One idea given for the mysterious disappearance of Neanderthals around 40,000 years ago is a difference in brain power compared with early modern humans (Homo sapiens), who invaded their territory in Eurasia and outcompeted them. But a new study of brain variation reveals that Neanderthals and humans were much more alike than previously assumed.

Neanderthal skulls are quite obviously different in shape from those of early modern humans. While Neanderthals had longer, lower skulls with heavier brow ridges and larger nasal openings, modern humans have more globular skulls with smaller facial features. The inside of the skull, called the endocranium, also looks different in Neanderthals versus modern humans.

"These shape differences have long been used to suggest Neanderthals differed cognitively from modern humans," first author Tom Schoenemann, an anthropologist at Indiana University Bloomington, and colleagues wrote in a study published Monday (April 27) in the journal PNAS.

Because of the anatomical differences in the skulls, many experts have assumed that Neanderthals couldn't talk as well as humans, had poor planning skills, and had limited short-term memory. But, problematically, these differences "were not put into the context of modern human populational variation in brain anatomy, which is known to be substantial," the researchers wrote.

To better understand variation in brain anatomy, the researchers compared two large MRI datasets of the brains of living people: 100 ethnic Han Chinese and 100 Americans with European ancestry. In nearly 70% of the brain regions the researchers assessed, they found that the volume differences between the group of Chinese brains and American brains were larger than those previously found between Neanderthals and early modern humans.

"This evidence does not support the idea of Neanderthals having significantly different brains and cognitive abilities compared to anatomically modern humans that existed at the time," Schoenemann told Live Science in an email.

If modern human population differences are not evolutionarily significant, which is what experts assume, then similar brain differences between Neanderthals and early modern humans would also not be considered evolutionarily significant, the researchers wrote.

The researchers noted that even small differences in behavior and brain size can potentially have significant evolutionary consequences. One of the largest differences between Neanderthal and H. sapiens brains was found to be correlated with attention and inhibition, suggesting Neanderthals may have had a slightly lower executive functioning ability. However, "the correlations between brain anatomy and cognition are very weak," Schoenemann said, and "even if the differences in brain anatomy are correct, the implied cognitive differences would be very small."

Since Neanderthals disappeared relatively quickly after modern humans arrived, "it is not clear that such small differences could actually have meaningfully contributed to their replacement," the researchers wrote. Given that human brains differ between living populations today to a greater degree than Neanderthal and early modern human brains differed some 40,000 years ago, the researchers don't think Neanderthals died out because they lacked the intelligence to adapt.

The new study "strongly points to demography and genetic swamping — possibly as a result of some kinds of cultural differences — and not to innate differences in cognitive ability as the most likely cause of Neanderthal replacement," the researchers wrote. This idea — in which the genes of a minority species are overwhelmed by those of the majority species — echoes recent research that has modeled the integration of H. sapiens into Neanderthal populations, which could have led to the latter's disappearance within as little as 10,000 years.

More research along these lines may be warranted, the researchers concluded, since they only compared the brains of Chinese and American people.

"It is entirely possible that even larger differences exist among modern human populations, further calling into question the evolutionary significance of the estimated Neanderthal differences in brain anatomy with contemporary anatomically modern H. sapiens," they wrote.

Editor's note: This story was updated at 4:36 p.m. EDT to include quotes from study first author Tom Schoenemann.

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Neanderthal toddlers grew faster than their modern human counterparts, likely as an adaptation to living in a cold, harsh environment, new research suggests.

The discovery, which was made using the bones of a young Neanderthal discovered in Amud Cave in northern Israel in the 1990s, suggests that Neanderthals and modern humans (Homo sapiens) followed different evolutionary paths after they split from a common ancestor around 600,000 years ago, the researchers reported April 15 in the journal Current Biology.

The Neanderthal child's partial skeleton, called Amud 7, had been placed in a niche in the cave wall with a red deer (Cervus elaphus) jaw on top of it, possibly as a burial offering. Based on stone tools and the shape of the bones, archaeologists determined that the Amud Cave skeletons were Neanderthals who lived sometime between 51,000 and 56,000 years ago.

The Amud 7 skeleton was found in more than 100 pieces, which included fragments of the child's arms, legs, chest and skull, all of which displayed distinctively Neanderthal anatomical features even at the child's young age. However, because Neanderthal infant skeletons are rarely found, the actual age at death of Amud 7 has been difficult for researchers to pin down.

Archaeologists typically estimate an ancient child's age based on the growth and eruption of teeth and on the size and completeness of various bones. The growth curves for the bones and teeth of modern human babies are well documented, but Amud 7 has revealed that at least one of the Neanderthals' growth stages was much faster than modern humans'.

When the researchers compared the tooth development of Amud 7 with that of modern humans, they found that the Neanderthal's lower front teeth yielded an age estimate of about 6 months. But Amud 7's bones were more in line with those of a 14-month-old modern human. This discrepancy is likely related to differing growth stages, the researchers wrote in the study.

While newborn Neanderthals were comparable with modern human newborns in terms of tooth formation, tooth eruption and the lengths of the arm and leg bones, they had significantly larger skulls. In the second growth stage — infants, toddlers and young children, or about 1 to 6 years old — Neanderthals' bodies grew significantly faster than their teeth, while modern human babies' teeth and bodies grew more proportionately. Then, in later childhood, Neanderthals' body growth and tooth development evened out and more closely matched modern human children's trajectories, the researchers found.

"The results of this study suggest that the growth trajectory of young Neandertal infants may have differed from that of H. sapiens," the researchers wrote in the study. Specifically, Neanderthal babies' bodies developed more rapidly than modern humans' did in the first years of life but then evened out during later childhood. "This suggests an evolutionary strategy emphasizing accelerated development in the early years of life, likely advantageous in the harsh environments Neandertals inhabited," the researchers wrote.

Although this new analysis of the Amud 7 skeleton reveals important information about Neanderthal children's growth and development, the researchers cautioned that more data is needed from other non-adult Neanderthal skeletons. They noted that a larger sample size may shed light on whether this pattern was widespread or a specific ecological adaptation.

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Before Neanderthals went extinct, they experienced a major upheaval that resulted in just one of their genetic lineages surviving in Europe and then expanding across the continent, a new study shows.

The findings, published March 23 in the journal PNAS, may shed light on what ultimately doomed the Neanderthals.

Neanderthals were among the closest relatives of modern humans (Homo sapiens), with their lineages diverging around 500,000 years ago. Although Neanderthals once ranged across Eurasia, they are generally thought to have gone extinct about 40,000 years ago.

DNA recovered from Neanderthal fossils can shed light not just on their extinction but on their history in general. In the new study, researchers examined DNA from mitochondria in cells, which help generate energy for the body, and get passed down from mothers to offspring.

The scientists gathered 10 mitochondrial DNA sequences from Neanderthals excavated from six archaeological sites in Belgium, France, Germany and Serbia. They analyzed them alongside 49 Neanderthal mitochondrial DNA sequences released in previous research.

The team found that in Europe, where Neanderthals ultimately died out, several mitochondrial DNA lineages existed until about 65,000 years ago. After this point, these groups were replaced by a single Neanderthal mitochondrial genetic lineage originating from southwestern France. These "Late Neanderthals" proceeded to disperse across Europe.

"This tells us there was this major disruption in Neanderthal history," study senior author Cosimo Posth, a paleogeneticist at the University of Tübingen in Germany, told Live Science. "There was really a genetic transformation."

Posth noted that about 75,000 years ago, glaciers came to dominate Europe.

"We don't think our findings suggest that Neanderthals were migrating to the Mediterranean," he said. "We think Neanderthal groups in northern Europe perished, while a Neanderthal group that was already in southwestern France survived this climate change and then went on to expand across a broader region. Neanderthals had experienced multiple glaciations before, but the last one proved harsh on their survival."

The study also found that "there was a kind of genetic impoverishment among the Late Neanderthals," Posth said. "Since they appeared to emerge from this single group, their genetic diversity overall was reduced drastically compared to what came before — they were all extremely similar on a genetic level across Europe, from Spain to the Caucasus to northern Europe."

This low genetic diversity ‪—‬ which grew most pronounced about 42,000 years ago, shortly before Neanderthals generally died out ‪—‬ "might have played a role in their extinction," Posth noted. "We don't think there was a single reason the Neanderthals went extinct, but this lack of genetic diversity would have made them more predisposed to not really survive climatic changes and other disruptions."

Likewise, Neanderthal groups in the Altai Mountains of Siberia were more closely related to each other than to European Neanderthals, and these Siberian Neanderthals also had low genetic diversity and lived in small, isolated groups, another March 23 study published in the journal PNAS found.

Despite this low genetic diversity, the Late Neanderthals in Europe appeared quite diverse across sites in terms of their artifacts and art. "So after the Neanderthals re-expanded across Europe, we think that Late Neanderthal groups were not highly connected with each other," Posth said. "This would have led to more inbred groups, explaining the low genetic diversity, but also more cultural and archaeological diversity, since these groups were isolated and so would have developed more specialized cultures."

"We've seen evidence that Neanderthal populations replaced each other, and this paper really creates a ground story as to why that might be — because Neanderthals went extinct in places all the time, and then other Neanderthal groups went in and recolonized the same places," Fernando Villanea, a population geneticist at the University of Colorado Boulder who was not involved in the study, told Live Science.

Future research could seek to test these findings by analyzing DNA from Neanderthal cell nuclei instead of their mitochondria, Posth said. However, this will be a major challenge, as DNA from nuclei is several hundred times less abundant than DNA from mitochondria in cells.

Neanderthal quiz: How much do you know about our closest relatives?

Two Neanderthals present at the same cave site 10 millennia apart were distant relatives, a tiny 110,000-year-old bone fragment from the Altai Mountains in Siberia reveals. The fragment has also produced the fourth full genome of a Neanderthal to date, shedding light on how small and isolated Neanderthals were long before they disappeared around 40,000 years ago.

Researchers found the bone fragment in Denisova Cave, which both Neanderthals and Denisovans lived in off and on for nearly 300,000 years. In a study published Monday (March 23) in the journal PNAS, the researchers compared the genome of the 110,000-year-old Neanderthal male (called D17) with three other complete Neanderthal genomes to better understand Neanderthals' population structure.

The researchers compared the genome of D17 with the genome of a female Neanderthal (called D5) dated to 120,000 years ago from the same cave. They found that, while D5 was not a direct ancestor of D17, the two Neanderthals belonged to closely related lineages connected by a common ancestor. This distant biological relationship suggests Neanderthals had a long-term presence in the Altai region, the researchers said.

"But it is likely that Denisova Cave was part of a broader landscape used repeatedly by these Neanderthal populations over time, rather than a site occupied by a single, continuous group," study first author Diyendo Massilani, a genetics professor at the Yale School of Medicine, told Live Science in an email.

The study results also revealed that Neanderthals in the Altai region lived in very small and highly isolated populations of 50 or fewer people, as shown by stronger genetic markers of inbreeding. Specifically, researchers found that the individuals they analyzed had large sections of identical DNA, an indication that their parents were very closely related — as close as first cousins, for example.

The new research complements previous studies that showed Neanderthals lived in smaller and more isolated groups than our own species did. A 2022 study indicated that one Altai Neanderthal community numbered around 20 individuals, while another study provided evidence of a group being isolated for roughly 50,000 years. Many researchers have pointed to inbreeding and isolation as causes for Neanderthals' disappearance around 40,000 years ago. But the latest results suggest that Neanderthals also survived for long periods under extreme conditions of isolation and small population size.

Massiliani and colleagues also discovered that Altai Neanderthals were very different from later European Neanderthals. In their genetic analysis, the researchers found that Altai Neanderthal D17 was more closely related to D5 than either of them was to Neanderthals in Europe or to later populations in the Altai region. This suggests that Neanderthal populations from eastern and western Eurasia became genetically different from one another in a relatively short time frame and within a fairly small geographic area.

"Even though the individuals from which we have genomes were separated for only about 50,000 years on average, they reached levels of difference similar to what we see today between some of the most distinct human populations, like people from Central Africa and Papua New Guinea that separated about 300,000 years ago," Massilani said.

Likely because they were small and isolated, Neanderthal populations became genetically distinct from one another much more quickly, Massilani said. This may have been because in small, isolated groups, a process called genetic drift can cause random genetic changes to become more common over time.

"We already knew that Neanderthals were not a single, homogeneous population spread across Eurasia, but a patchwork of groups shaped by complex demographic processes, including divergence, migration, local extinctions and replacements," he said. "What is striking in our results is just how differentiated these populations could become."

The high amount of genetic separation and differences between groups may have limited Neanderthals' ability to adapt to environmental changes, Massilani said.

The study provides new details about how Neanderthal populations were structured, one expert said.

"To have two sequenced Neanderthals in such a close geographic place does bring new and more fine-grained insight" into their population, Léo Planche, a population geneticist at Paris-Saclay University's Interdisciplinary Laboratory for Digital Sciences who was not involved in the study, told Live Science in an email. "We start to have enough Neanderthal genomes to actually have some claim about their population structure. Populations are groups of individuals, so the more data the better."

Editor's note: This article was updated on March 27, 2026 to note that the vast majority of Neanderthals went extinct 40,000 years ago, not 34,000 years ago as was previously stated.

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When Neanderthals and modern humans first got together, they preferred pairings between Neanderthal men and human women, a new study of ancient and modern genomes suggests. The finding helps to explain why modern humans (Homo sapiens) have a relatively low level of Neanderthal genes and why those genes are found in some populations today and not in others.

Ever since the first modern-human and Neanderthal genomes were sequenced over 20 years ago, scientists have puzzled over "Neanderthal deserts," or places in the modern-human genome where Neanderthal genes are rare. The two groups interbred during a few periods after their ancestors split around 600,000 years ago. The result is that most non-African people on the planet today carry an average of 2% Neanderthal DNA, while some African groups have up to 1.5%, which was inherited from H. sapiens who mixed with Neanderthals in Eurasia and then moved to Africa.

But what has stymied experts is that the genes we inherited from Neanderthals are found only in tiny patches on our X chromosome, even though those genes appear in greater numbers across our other chromosomes. There are regions on the X chromosome — the sex chromosome that every human has at least one copy of — where no living humans have any Neanderthal ancestry.

"For years, we just assumed these deserts existed because certain Neanderthal genes were biologically 'toxic' to humans — as tends to be the case when species diverge — so we thought the genes may have caused health problems and were likely purged by natural selection," Alexander Platt, a population geneticist at the University of Pennsylvania, said in a statement.

But in a study published Thursday (Feb. 26) in the journal Science, Platt and colleagues concluded that the most plausible explanation for these "Neanderthal deserts" is actually mate preference, an evolutionary mechanism that is a major part of sexual selection. Biologists commonly illustrate the evolutionary result of mate preference with the large, colorful tail of the male peacock. Early humans and Neanderthals likely chose their mates for specific reasons as well.

DNA deep dive

The researchers analyzed the genomes of 73 women from three modern-day African populations that have no Neanderthal ancestry, including the !Xoo, Ju|'hoansi and Khoisan, and compared them with the genomes of a few Neanderthals. First, they looked at the Neanderthals' X chromosomes and found significantly higher amounts of modern-human ancestry there than on the other Neanderthal chromosomes. This result revealed that the lack of Neanderthal genes in the human X chromosome is not the result of incompatibility, which would have suggested Neanderthal genes caused modern humans problems and were eliminated through natural selection.

Rather, the surprisingly high amount of modern human DNA chunks found in Neanderthals can be explained by mate preference, the researchers concluded. Because females carry two X chromosomes and males carry only one, a preference for mating between female H. sapiens and male Neanderthals would mean fewer Neanderthal X chromosomes would enter the human gene pool, producing the pattern the researchers identified in the genomes.

But the reasons for the mate preference — and the direction of it — remain elusive.

"I have no idea whose preference is being expressed here," Platt told Live Science in an email.

Previous research into the Neanderthal Y chromosome — one of the two sex chromosomes of male individuals — indicates there was interbreeding between male H. sapiens and female Neanderthals. But it is apparent from the new study that, in effect, male Neanderthals and female H. sapiens liked each other more than female Neanderthals and male H. sapiens did.

"We simply don't have a genetic signature to discern beyond that at the moment," Platt said.

The researchers did not rule out more complicated evolutionary scenarios that might have combined natural selection, sex biases, mate preference and sex-specific migration to contribute to the "Neanderthal deserts" in the human genome.

Questions about the structure of Neanderthal and modern-human societies are also important to answer for a fuller understanding of mate choice in the past, as anthropologists and evolutionary biologists who have studied the phenomenon show that mate choice is partially learned.

The research team plans to "look at the evolution of the social structures and gender roles within Neanderthals," which "could conceivably shed some light on the picture," Platt said. "But I think we're a long way from knowing this."

Neanderthal quiz: How much do you know about our closest relatives?

The mysterious disappearance of our Neanderthal cousins may have been related to preeclampsia, a life-threatening complication of pregnancy and/or the postpartum period, doctors propose in a new study. But experts in paleoanthropology are not convinced.

In a paper published Jan. 30 in the Journal of Reproductive Immunology, an international team of neonatologists and OB-GYNs argued that preeclampsia and eclampsia — a related disorder that involves one or more seizures during pregnancy or the postpartum period — have "never been seriously considered in hypotheses concerning Neanderthal reproductive biology and their eventual extinction."

These conditions are not fully understood by medical experts, but they appear to be related to an evolutionary quirk of the human placenta — which, given the number of genes we share with our extinct relatives, also may have affected the Neanderthal placenta. (However, the researchers did not investigate any such genes in the new study.)

Preeclampsia in human species

Preeclampsia involves dangerously elevated blood pressure and can put strain on the pregnant person's heart and other organs, including the kidneys and liver. The condition affects up to 8% of pregnancies today, and it can also occur during the postpartum period. It can also progress to eclampsia, which involves seizures and, sometimes, brain damage. If not treated, both conditions can be life-threatening for the pregnant person and the fetus.

Research into preeclampsia has shown that abnormal, shallow implantation of the placenta in the uterus may be one possible cause of the condition. The exceptional metabolic demands of babies of large-brained human species were likely responsible for the deep implantation of the placenta to ensure sufficient maternal-fetal nutrient transfer, the researchers wrote.

An inadequately placed placenta's efforts to acquire adequate nutrients for the fetus can lead to a rise in maternal blood pressure, particularly in the third trimester, when the fetus's brain is rapidly developing, according to this hypothesis. This can lead to preeclampsia, eclampsia and fetal growth restriction, all of which complicate pregnancy and threaten the survival of mothers and babies.

Given this insight into preeclampsia, the study authors wrote that the condition "may have constituted an additional, underappreciated selective pressure on Neanderthals, contributing to their extinction." They hypothesized that Neanderthals "may have lacked a key protective mechanism" against preeclampsia that some of the study authors previously suggested modern humans have. This idea, however, is still speculative and such a mechanism has yet to be found.

If Neanderthals lacked a "maternal safety mechanism" to avoid preeclampsia, this may have led to reproductive loss and maternal mortality, thus hastening their extinction as a group, the team proposed.

Anthropologists respond

But experts in Neanderthal archaeology and genetics are not convinced, particularly since the new study does not provide any evidence that Neanderthals dealt with preeclampsia.

"The 'preeclampsia doomed Neanderthals' framing goes well beyond the available evidence," Patrick Eppenberger, co-head of the Evolutionary Pathophysiology and Mummy Studies Group at the Institute of Evolutionary Medicine in Zurich who was not involved in the study, told Live Science in an email.

While Eppenberger agreed that preeclampsia is uniquely human and linked to the evolution of the human placenta, he said that "what is much harder to support is the claim that it was more frequent or more lethal in Neanderthals than in early Homo sapiens or that it played a primary role in their disappearance, especially given Neanderthals' long persistence" over more than 300,000 years.

In his own research, Eppenberger discovered that a red blood cell gene variant between Neanderthals and modern humans may have caused some hybrid babies to fail to survive, which could have hastened their extinction.

"Why Neanderthals went extinct is a question that has captured the imagination of the public and researchers," April Nowell, a Paleolithic archaeologist at the University of Victoria in Canada who was not involved in the study, told Live Science in an email, and "everyone is looking for a smoking gun."

But the reasons for Neanderthals' disappearance are complicated. "I have long argued that differential survivorship of the littlest Neanderthals is key to understanding the Neanderthal story, but I am not particularly persuaded by this study," Nowell said.

If the researchers are correct that H. sapiens evolved a mechanism to mitigate preeclampsia, Nowell said, the condition could have contributed to Neanderthals' extinction. But given the widespread evidence of gene sharing among groups of humans, "to my mind, it is equally possible that Neanderthals, Denisovans and Homo sapiens shared this mitigating mechanism," Nowell said.

"I think the paper is an interesting evolutionary-medicine thought experiment," Eppenberger said. Although there is no direct evidence currently that Neanderthals had higher rates of preeclampsia or eclampsia than modern humans do, Eppenberger said, there may be ways to test the researchers' theory, including investigating genes involved in maternal-fetal immune interactions and in the regulation of placental and fetal growth. But we might not get a clear answer.

"Genetics can provide clues about plausibility and population differences, but it likely won't 'confirm' preeclampsia in Neanderthals the way clinical data would," Eppenberger said.

The study authors did not respond to a request for comment by the time of publication.

Neanderthal quiz: How much do you know about our closest relatives?

About 37,000 years ago, Neanderthals clustered in small groups in what is now southern Spain. Their lives may have been transformed by the eruption of the Phlegraean Fields in Italy a few thousand years earlier, when the caldera's massive explosion disrupted food chains across the Mediterranean region.

They may have gone about their daily life: Crafting stone tools, eating birds and mushrooms, engraving symbols on rocks, and creating jewelry out of feathers and shells.

They likely never realized they were among the last of their kind.

But the story of their extinction actually begins tens of thousands of years earlier, when the Neanderthals became isolated and dispersed, eventually ending nearly half a million years of successful existence in some of the most forbidding regions of Eurasia.

By 34,000 years ago, our closest relatives had effectively gone extinct. But because modern humans and Neanderthals overlapped in time and space for thousands of years, archaeologists have long wondered whether our species wiped out our closest relatives. This may have occurred directly, such as through violence and warfare, or indirectly, through disease or competition for resources.

Now, researchers are solving the mystery of how the Neanderthals died out — and what role our species played in their demise.

"I think the fact is, we do know what happened to Neanderthals, and it is complex," Shara Bailey, a biological anthropologist at New York University, told Live Science.

Decades of research has revealed a complex picture: A perfect storm of factors — including competition among Neanderthal groups, inbreeding and, yes, modern humans — helped erase our closest relatives from the planet.

The rise and demise of our closest human relatives

The modern story of Neanderthals began in 1856, when quarry workers found a strange-looking, not-quite-human skull in Germany's Neander Valley.

Archaeologists gave the skull a new species name: Homo neanderthalensis. And in the early decades after the discovery, researchers assumed the creatures were knuckle-dragging brutes. This depiction was based on a flawed reconstruction of a skeleton of an old Neanderthal man, whose spine was deformed by arthritis, found at La Chapelle-aux-Saints in France.

Now, more than 150 years of archaeological and genetic evidence makes it clear that these early human relatives were much more advanced than we originally thought. Neanderthals crafted sophisticated tools, may have made art, decorated their bodies, buried their dead, and had advanced communication abilities, albeit a more primitive kind of language than modern humans used. What's more, they survived for hundreds of thousands of years in the hostile climates of Northern Europe and Siberia.

Before they met in Eurasia, Neanderthals and modern humans last shared an ancestor in the Middle Pleistocene epoch, between 600,000 and 800,000 years ago. Modern humans and Neanderthals evolved separately; Neanderthals adapted to cold climates with sturdier bodies, larger faces and different metabolic processes than the taller, thinner Homo sapiens. Neanderthals evolved in Eurasia about 400,000 years ago, and H. sapiens arrived significantly later, evolving in Africa 300,000 years ago and settling in Europe between about 55,000 and 45,000 years ago.

Based on archaeological evidence from sites from Russia to the Iberian Peninsula, Neanderthals and modern humans likely overlapped for at least 2,600 years — and perhaps as long as 7,000 years — in Europe. That overlap occurred during a bleak period in Neanderthal history that ended with their downfall — raising the question of whether modern humans were responsible for killing them off.

But the story of Neanderthal life — and extinction — is one of regional variation, said Tom Higham, an archaeological scientist at the University of Vienna.

"In some areas, for example, we see that humans arrive to empty spaces in Europe where there aren't any Neanderthals anymore, seemingly," Higham told Live Science. "And in other places, we see that there's probably an overlap that happens … we know that people are interbreeding."

The first empirical proof of that interbreeding was found in 2010, when a Neanderthal genome was sequenced. Since then, genetic analysis has shown that Neanderthals and modern humans shared much more than a geographic area — we regularly exchanged DNA back and forth, meaning there is a bit of Neanderthal in every modern human population studied to date.

Related: 'More Neanderthal than human': How your health may depend on DNA from our long-lost ancestors

Already on the brink

When modern humans and Neanderthals met tens of thousands of years ago, the latter were probably already in trouble. Genetic studies suggest that Neanderthals had lower genetic diversity and smaller group sizes than modern humans, hinting at a potential reason for Neanderthals' demise.

"Genetically, one big clue that we get is this idea of heterozygosity," Omer Gokcumen, an evolutionary genomicist at the University at Buffalo, told Live Science. An individual receives two copies, or alleles, of a gene from each parent. Individuals are "heterozygous" for a given gene if they inherit a different allele from each parent. In Neanderthals' small communities, which contained fewer than 20 adults in each group, more inbreeding occurred. That meant fewer of them inherited different versions of a gene from each parent and, therefore, had low heterozygosity.

"Neanderthals may have suffered for that — what they call a mutational burden," Gokcumen said. Genetic research suggests Neanderthals had many problematic mutations that likely affected their survival, including a rare blood type. "Because of their small population size, they couldn't actually breed these bad alleles out, and their kids may actually be sickly at the end," Gokcumen said.

Any population of animals survives into the future through successful reproduction and rearing of offspring. Researchers estimating the mortality rates of Neanderthal infants have found that a decrease of even 1.5% in the survivorship of these children could result in population extinction within 2,000 years, April Nowell, a Paleolithic archaeologist at the University of Victoria in British Columbia, told Live Science.

"There doesn't have to be very much going on to really have a dramatic impact on the viability of your population," Nowell said.

So while Neanderthal populations began decreasing until they became small, isolated groups without the social support necessary to care for their increasingly sickly babies, modern human groups quickly expanded through Europe.

Humans and Neanderthals: A bad mix?

During two periods across Eurasia 135,000 and 100,000 years ago, Neanderthal populations nearly died out. But they bounced back, powering through these cold snaps and the resulting changes to their landscapes.

"Neanderthals survived all of these hardships," Bailey said. "It wasn't until they had the additional pressure of Homo sapiens that they eventually went extinct."

Given the overlap in time and space, researchers used to think modern humans played a direct role in Neanderthals' demise via warfare or novel diseases.

There is some evidence of violence on Neanderthal skeletons. A young adult male from St. Césaire, France, dating to around 40,000 years ago suffered a fracture to the top of his head made with a sharp implement, and an older male found in Shanidar Cave, Iraq, dating to around 50,000 years ago had a partially healed stab wound on his left rib. But there's no way to say whether modern humans or other Neanderthals inflicted this violence. Unless archaeologists find a site where Neanderthals are clearly the victims of a massacre inflicted by modern humans, it will be impossible to conclude that modern-human violence was a major cause of Neanderthals' extinction.

Nor is there genetic evidence that modern humans' diseases killed off the Neanderthals, though we do share many immune-related genes. For instance, we inherited Neanderthal genes that make us susceptible to autoimmune disorders such as lupus and Crohn's disease as well as to severe COVID-19. Future genetic analyses may reveal the potential role of disease in Neanderthals' demise, Gokcumen said.

Winners and losers in the fight for resources

But warfare and pestilence aren't the only possible ways modern humans may have led to Neanderthals' vanishing. When two groups come together, competition can lead to tragic outcomes.

Neanderthal artifacts, such as pendants, etchings and fire-making kits, show that Neanderthals were intelligent. But new research suggests there are significant differences between H. sapiens and Neanderthal brains: Modern humans have more neurons in brain regions key to higher-level thinking, and their neurons are more connected — meaning modern humans were likely more capable of thinking quickly. Combined with Neanderthals' greater difficulty in processing language, this could mean modern humans had an advantage in key tasks, Nowell said, such as hunting and foraging for food.

And while Neanderthals' extremely isolated groups may have had a biological disadvantage, they probably had a cultural one, too.

"Ideas can spread more easily when you have bigger populations and other people can build on them," Bailey said. But given Neanderthals' disparate populations, "their artistic or cultural kinds of innovations might not have progressed the way we see in much larger populations that have a lot of interactions with people," she said.

Although Neanderthals created tools that were very sophisticated for the time, we haven't found any unambiguous long-range weapons made by Neanderthals. Modern humans' ability to devise projectile weapons, by contrast, may have given us a survival advantage.

Related: Could Neanderthals talk?

But the full implications of these differences on Neanderthals' survival aren't yet known.

"We could also think about intergroup competition or competition between groups of Neanderthals," Nowell suggested, as a potential result of their dwindling numbers and modern humans' encroachment.

When looking at contemporary and historical hunter-gatherer groups, Nowell and co-author Melanie Chang, a paleoanthropologist at Portland State University, noticed that these groups often tightly regulate who has been able to use the land and its resources, and that being part of the "in group" can be a matter of survival. As Neanderthals began to disappear from most of Eurasia and retreat to southern Iberia, competition among Neanderthal groups would have risen.

"Maybe it's competition with other Neanderthals that prompts them to start differentiating themselves more," Nowell said.

That seems particularly persuasive, given that around 40,000 to 50,000 years ago, there was a cultural explosion among both modern human and Neanderthal groups. These cultural elements included a surge in personal adornment, such as painted shells, probably worn as pendants, that could have served as "group" symbols, Nowell said.

No cohesive, shared fate

Given the mounting evidence that Neanderthals and modern humans interacted regularly for thousands of years, many researchers are looking to an unusual place for the answer to what happened to Neanderthals: a theory first put forward by paleoanthropologist Fred Smith and colleagues 35 years ago.

"He came up with this suggestion that there was gene flow and a slow assimilation of Neanderthals into human populations," Higham said.

In essence, the two groups simply got used to hanging out with one another, and as more and more humans moved into Eurasia, eventually their larger population swamped the Neanderthals, whose lineage petered out. This idea is supported by a study that found H. sapiens simply absorbed the Neanderthals into our population. In that way, we may have made Neanderthals vanish as a distinct group — by making some of the remaining ones part of our family.

But this theory currently lacks "smoking gun" evidence of humans and Neanderthals living together for extended periods at the same site. They were sharing genes, but the archaeological evidence does not show Neanderthals and modern humans sharing either a home or the close social ties necessary to say we assimilated Neanderthals into our own population.

"Until they find a frozen Neanderthal and a modern human in a locked embrace, it's always going to be open to interpretation," Bailey said.

Even if we do find such a site, it is unlikely to change the nuanced, complicated picture of Neanderthals during their last moments.

"Some Neanderthal populations died out, some got massacred, some interacted and some only exchanged ideas," Sang-Hee Lee, a biological anthropologist at the University of California, Riverside, told Live Science. "The really exciting questions like 'Why did Neanderthals disappear?' 'Why did they go extinct?' no longer can have one overarching theory" she said. "Neanderthals as a whole did not have a cohesive, shared fate."

Editor's Note: This story was originally published Oct. 4, 2024 and was updated on Feb. 13, 2026 to include reference to the latest research on Neanderthal blood type, genetic diversity and weapons-making capabilities.

Neanderthals purposefully collected and positioned horned and antlered animal skulls in a cave in what is now Spain, suggesting that these extinct human relatives had complex cultural practices over 43,000 years ago, a new study finds.

Des-Cubierta cave in central Iberia was initially discovered in 2009. In 2023, researchers announced the unusual discovery of an assortment of 35 large mammal skulls inside the cave. Most jaw bones were missing, but all skulls came from horned or antlered species like steppe bison and aurochs. Over 1,400 stone tools were uncovered in the same level, all in the Mousterian style typical of Neanderthals.

"At first glance, the deposit appears chaotic," study first author Lucía Villaescusa Fernández, a doctoral researcher in archaeology at the University of Alcalá in Spain, told Live Science in an email. "What initially looked like a disorganised accumulation of materials turned out to preserve a clear record of both geological processes and human activity," she said.

The cave experienced many rockfalls in the millennia following its use, so Villaescusa Fernández and her team teased the role of these disturbances apart from the Neanderthal activity. This confirmed the Neanderthals were collecting animal skulls over a long period of time in particularly cold periods between 135,000 and 43,000 years ago, according to a study published Jan. 3 in the journal Archaeological and Anthropological Sciences.

"This distinction is essential in archaeology because understanding past human behaviour requires first identifying which parts of the archaeological record were created by people and which were shaped by nature," Villaescusa Fernández said.

To fill this gap, Villaescusa Fernández and her colleagues carefully mapped the location of all the archaeological remains. They then compared the rockfall debris distribution with that of the animal bones and stone tools. It became clear that the bones had been purposefully positioned within the cave. "These materials had different origins and were not introduced into the cave by the same processes," Villaescusa Fernández said.

Although the timescale cannot be directly measured, and the precise duration of the practice remains uncertain, the team also found the animal skulls had been placed in specific areas of the cave repeatedly over a prolonged period of time. This suggests that this practice may have been maintained over generations and was not directly tied to economic or subsistence needs, Villaescusa Fernández said.

Exactly why Neanderthals collected the skulls is unclear, but the selection, treatment and placement of horned animal skulls in a cave they did not live in "highlights their capacity for cultural practices that are not directly related to survival," Villaescusa Fernández said. "This has important implications for how we understand Neanderthal societies, particularly in terms of cultural transmission and shared traditions," she added.

"Too often, discussions of Neanderthal symbolism rely on fragile evidence or optimistic interpretations," Ludovic Slimak, an archaeologist at the University of Toulouse in France and author of the book "The Naked Neanderthal" (Penguin, 2024) who was not involved in the study, told Live Science by email. "Here, the authors take a more grounded approach, testing whether the spatial organization of the remains could be explained by natural processes alone," he said.

Slimak said that the findings of this study add new evidence to the debate over Neanderthal symbolism. "Rather than asking whether Neanderthals were 'symbolic like us,' we should ask what kinds of meaningful behaviors they developed on their own terms. This site suggests that Neanderthal worlds of meaning existed, but they may have been structured very differently from those of Homo sapiens," he said.

Neanderthal quiz: How much do you know about our closest relatives?

A triangular artifact crafted from elephant bone was used by archaic human relatives to sharpen hand axes around 480,000 years ago in what is now the U.K., a new analysis reveals.

The item — which measures about 4.3 by 2.3 inches (10.9 by 5.8 centimeters) — represents the oldest known elephant bone tool ever found in Europe, according to the study, which was published Wednesday (Jan. 21) in the journal Science Advances, and demonstrates human relatives' high level of resourcefulness and ability to adapt to new environments as they settled in northern climates.

While evidence suggests that early human relatives used elephant bones and tusks throughout the Paleolithic period for a wide range of purposes, it's "very rare" to find an elephant-bone tool of this age or older anywhere in the world, said study co-author Silvia Bello, a paleoanthropologist at the Natural History Museum in London.

The "unexpected" find of one of the world's oldest elephant bone tools indicates a relatively advanced level of technological development, thus highlighting the innovation, resourcefulness and craftsmanship of archaic human relatives almost half a million years ago, the researchers said in the study.

While the researchers are unsure which group of human relatives used the elephant tool, given the age of the tool and the location where it was found, two candidates are early Neanderthals or Homo heidelbergensis, Bello told Live Science in an email.

The tool "provides an extraordinary glimpse into the ingenuity of the early human ancestors who made it," Bello said.

The fossilized bone artifact was originally uncovered in the early 1990s during excavations at the archaeological site of Boxgrove in southern England. This internationally renowned site has yielded many finds that have shed light on Paleolithic life around half a million years ago. These include various bone and stone tools, numerous animal remains displaying signs of butchery, and even the oldest human remains ever found in Britain.

The significance of the bone artifact was not immediately apparent. But a recent analysis of the artifact conducted by Bello and her co-author Simon Parfitt, an archaeologist at the Institute of Archaeology at University College London, revealed that the artifact represents an elephant bone fragment deliberately shaped into a "retoucher" tool.

Retouchers were used to shape and resharpen the edges of hand axes. The elephant bone retoucher would have contributed to the production of the "finely worked" hand axes that were thought to have been used primarily as cutting tools and are typical of Boxgrove, according to the study.

"The elephant bone tool shows signs of being shaped and used to knap and re-sharpen lithic tools while the bone was still fresh, suggesting that these humans knew that elephant bone was a great material for this," Bello said.

The find represents the only documented case of elephant bone being used to make a retoucher, according to the researchers. Knapping tools made from organic materials such as bone, antler and wood were essential pieces of equipment for early humans but are rarely preserved in the archaeological record.

Furthermore, prehistoric elephant bone remains are "exceptionally rare" at Boxgrove, suggesting that archaic humans in the area came across this resource infrequently, the study authors noted. Nonetheless, it appears that the creators of the tool recognized the usefulness of the material.

"This remarkable discovery showcases the resourcefulness of our ancient relatives," Parfitt told Live Science in an email. "They possessed not only a deep knowledge of the local materials around them, but also a sophisticated understanding of how to craft highly refined stone tools."

"Elephant bone would have been a rare but highly useful resource, and it's likely this was a tool of considerable value," he said in a statement.

Human evolution quiz: What do you know about Homo sapiens?

Scientists have identified the world's oldest known rock art — a hand stencil created at least 67,800 years ago in Indonesia.

This artwork, nestled in a cave in southeast Sulawesi, is also the earliest archaeological evidence of modern humans (Homo sapiens) living on the islands between the Asian and Australian continental shelves, according to a study published Wednesday (Jan. 21) in the journal Nature. The hand stencil is surrounded by younger rock art, including another hand stencil.

This discovery could fill a major gap in scientists' understanding of the journey the ancestors of Indigenous Australians took before reaching the continent at least 60,000 years ago. "It is very likely that the people who made these paintings in Sulawesi were part of the broader population that would later spread through the region and ultimately reach Australia," study first author Adhi Agus Oktaviana, an archaeologist at the National Research and Innovation Agency in Indonesia, said in a statement.

Although the rock art's original meaning is unknown, the hand stencils hint that the artists belonged to a relatively large group with its own cultural identity, study co-author Maxime Aubert, an archaeologist and geochemist at Griffith University in Australia, told Live Science. The hand stencils could have been made to signify group membership, Aubert said. "If you know about that cave and you know about this rock art, you're part of that group, you're part of that culture," he said.

Prehistoric art

Prehistoric rock art — or art on a rock face like a cave wall or a rock shelter — has been discovered all around the world, from 12,000-year-old engravings in Saudi Arabia to 4,000-year-old paintings along the U.S.-Mexico border. The oldest dated rock art previously identified — a roughly 66,700-year-old hand stencil in Spain — was believed to have been made by Neanderthals, as current evidence suggests modern humans didn't reach Europe until 54,000 years ago. But the dating technique used for that discovery is debated.

However, humans have been creating art for even longer than these examples. The oldest known drawing is a 73,000-year-old hashtag on a stone from South Africa, and a 540,000-year-old shell with zigzag carvings from Indonesia may have been crafted by Homo erectus.

Sulawesi also has a longstanding artistic legacy, with a depiction of a human interacting with a warty pig dating to 51,200 years ago. As part of a broader project documenting the prehistoric artwork on Sulawesi, Aubert and his team inspected 11 designs found in eight caves: seven hand stencils, two human figures and two geometric patterns.

All these prehistoric works had lumps of calcium carbonate — called "cave popcorn" — growing over them. Because the cave popcorn must have developed after the artwork was created, dating these growths provides a minimum age for the underlying image. In a handful of instances, maximum ages could also be obtained as the pigment overlaid one of these mineral deposits.

During the project, the researchers dated one hand stencil, measuring 5.5 by 3.9 inches (14 by 10 centimeters), to at least 67,800 years ago, making it 1,100 years more ancient than the rock art linked to Neanderthals in Spain. The image has faded considerably, but the remains of the fingers and palm are still faintly visible. The fingers had been purposefully narrowed — an artistic technique only found in Sulawesi.

About 4.4 inches (11 cm) to the left of this artwork is a hand stencil created using darker pigment that dates to no older than 32,800 years ago. This shows that prehistoric humans used this cave as their canvas over a period of at least 35,000 years.

Although other human species once called Sulawesi home, the researchers believe H. sapiens created these artworks, because the narrowed fingers are technically complex to produce and modern humans are known to have lived in the region at the time.

The stencils may have been created by the individuals spraying pigment over their hands with their mouths. This opens up the possibility for DNA to be extracted from the artwork. "We could have the genetic signature of the people doing this," Aubert said. "That would be amazing."

The identification of the oldest rock art in Sulawesi is an important discovery because it adds another data point on the journey humans took to spread across Island Southeast Asia and Australia. As a critical point on the journey to Australia, this discovery supports the suggestion that modern humans reached Australia by sailing a northern route from present-day Borneo to Sulawesi and then through to western Papua (the western half of the island of New Guinea) or the Indonesian island of Misool, the authors wrote in the study.

"This is a stunning discovery," Chris Clarkson, a professor of archaeology also at Griffith University who was not involved in the new research, told Live Science in an email.

He agreed with the conclusion that ancient modern humans are the most likely artists of the hand stencils because the dates align perfectly with when H. sapiens arrived in the region.

"What amazes me most is that these artworks sit directly on a migration route into Australia," he said. What's more, it shows that the first people to populate Australia had rich cultural lives. "The first people to cross Island Southeast Asia and reach Australia weren't just surviving, they were creating art, crossing oceans, and carrying complex symbolic traditions," Clarkson said.

Human evolution quiz: What do you know about Homo sapiens?

The 5,300-year-old Ötzi the Iceman mummy and a prehistoric man who lived in Siberia 45,000 years ago both carried a cancer-causing strain of human papillomavirus (HPV), new research finds.

Scientists analyzed ancient genetic data previously collected from the individuals, and found that both were likely infected with HPV16, a preprint paper posted to bioRxiv on Dec. 16, reported. In the study, which has yet to undergo peer-review, the authors present what they say is the "earliest molecular evidence" of HPV16 in modern humans.

This extremely early evidence of HPV16 in modern humans challenges the idea that Neanderthals, who overlapped with us in Eurasia from around 60,000 to 34,000 years ago in Eurasia, were the ones who transmitted the virus to us, the researchers said. But the team acknowledged that their sample size of two is small, so it's still hard to know where HPV16 originated.

HPV in ancient humans

HPV encompasses a diverse family of viruses that are primarily transmitted through direct skin-to-skin or sexual contact, and they are commonly found in humans today. Most infections are symptomless but in a small fraction of cases, HPV16 and other high-risk types (known as "oncogenic" papillomaviruses) can fuel the development of some cancers.

While the clinical significance of papillomaviruses is well understood, little is known about their occurrence among prehistoric human populations. In the study, the authors explored a long-standing question of how far back cancer-linked papillomaviruses — particularly HPV16 — have circulated in modern humans, study co-author Marcelo Briones, a professor at the Center for Medical Bioinformatics at the Medical School of the Federal University of São Paulo, Brazil, told Live Science in an email.

"The results indicate that HPV16 has been associated with anatomically modern humans for a very long time, likely well before major population splits outside Africa," or before 50,000 to 60,000 years ago, Briones said. "This supports the idea that oncogenic human papillomaviruses are not recent pathogens but long-term companions of their hosts, evolving alongside primates and humans over extended evolutionary timescales."

The researchers re-analyzed publicly available genome sequencing datasets for both Ötzi and the Siberian man, known as Ust'-Ishim. These individuals were chosen because they represent two of the best-preserved and best-characterized ancient human genomes available, Briones said.

Ötzi is a naturally mummified man whose 5,300-year-old remains were discovered in 1991 high in the Alps mountain range on the Austria-Italy border. His remarkably well-preserved body, clothing and tools have since provided a rare glimpse into prehistoric life in the region. The Ust'-Ishim man, meanwhile, who was discovered in 2008, lived around 45,000 years ago in what is now western Siberia. His remains — a single leg bone — yielded one of the oldest modern human genomes ever to be fully sequenced.

Briones and colleagues searched the genetic datasets for DNA fragments matching known HPV genomes. They found multiple DNA fragments matching HPV16 (specifically, a lineage known as HPV16A) in both individuals, suggesting the virus was present in them.

Most previous hypotheses about when HPV16 emerged in modern humans relied on computer models of how the virus evolves over time. These suggest the virus has ancient evolutionary origins but lacked direct biological confirmation, according to the researcher. In general, computer models suggest that papillomaviruses likely co-evolved with vertebrates for hundreds of millions of years.

While the preprint does not address the ultimate origins of HPVs as a group, it does show at least one high-risk type was present in modern humans at least 45,000 years ago.

Given this early date, the new findings challenge a previously proposed hypothesis that Neanderthals transmitted HPV16A to prehistoric Homo sapiens populations through interbreeding, Briones said. Although he said the new study's conclusions are "limited" by the small dataset.

Koenraad Van Doorslaer, interim co-chair of the immunobiology department at the University of Arizona who was not involved in the study, told Live Science in an email he "largely" agreed with the paper's conclusions, noting the authors "rigorously demonstrated" that both individuals were likely infected with HPV16.

"I am genuinely excited about the implications of this study because it supports some critical assumptions about the history of this family of important viruses," Van Doorslaer said.

However, Van Doorslaer said the proposal of the study authors that their findings present a challenge to the idea that HPV16A first entered our species due to Neanderthal interbreeding "may be overstated" in light of the data presented. In part, because Ust'-Ishim was previously shown to have Neanderthal DNA in his genome, "suggesting that the interbreeding pre-dates Ust'-Ishim's life," Van Doorslaer said. "So since this sample both has Neanderthal DNA and HPV16 DNA, it does not prove that HPV16 does not come from Neanderthals."

Ötzi quiz: What do you know about the Iceman mummy who was murdered 5,300 years ago in the Alps?

The discovery of 773,000-year-old fossils in a cave in Morocco is transforming the geography of human origins by placing the start of the modern-human lineage squarely in northwestern Africa, according to a new study.

In the research, published Wednesday (Jan. 7) in the journal Nature, a team of Moroccan and French researchers detailed their analysis of a handful of bones they think represent the last common ancestor of modern humans (Homo sapiens), Neanderthals and Denisovans.

The researchers discovered the fossils in a cave called Grotte à Hominidés (Cave of Hominids) at the site of Thomas Quarry I in Casablanca, Morocco. The bones consist of three partial lower jaws, several vertebrae and numerous individual teeth, all of which share some characteristics of Homo erectus but also have traits distinct from this human ancestor.

Additionally, there were numerous stone tools at the site, and one leg bone suggests that hyenas might have dined on the hominins. By testing the magnetic properties of 180 samples of sediment from around the fossils, the researchers found that the sequence spanned the Matuyama-Brunhes magnetic-field reversal, a geological event that occurred 773,000 years ago.

The new discovery fills a major gap in the African hominin fossil record between 1 million and 600,000 years ago, study co-author Jean-Jacques Hublin, a paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, told Live Science in an email. Genetic evidence has suggested that, during this time span, the last common ancestor of modern humans, Neanderthals and Denisovans was living in Africa.

Hublin and colleagues think the Thomas Quarry fossils are the best candidates yet for the "root" of the ancestral tree that led to our species and our archaic cousins.

While the early chapters of the story of human evolution took place in eastern and southern Africa, the last million years of our evolution are complicated by our ancestors' tendency to wander throughout Africa and Eurasia.

After H. erectus evolved in Africa around 2 million years ago, some groups spread eastward, reaching as far as Oceania. But others stayed put, evolved further and spread north into Europe around 800,000 years ago, where the groups from Spain are known as Homo antecessor and are the most likely direct ancestor of Neanderthals.

The newly analyzed Moroccan fossils are from roughly the same time period as H. antecessor and share some of their distinctive traits, which "may reflect intermittent connections across the Strait of Gibraltar that deserve further investigation," Hublin said. The Thomas Quarry fossils, however, are distinct from both H. erectus and H. antecessor.

"This supports a deep African origin for Homo sapiens and argues against Eurasian origin scenarios," Hublin said.

More work on the exceptionally rich fossil record of North Africa is needed to expand an understanding of human origins that is based largely on eastern and southern Africa, Hublin said, particularly since the clearest early evidence of H. sapiens comes from the 300,000-year-old site of Jebel Irhoud in Morocco.

A focus on this geographic area may also reveal new clues about the split between our species and our Neanderthal and Denisovan cousins.

"While we cannot claim that the emergence of the lineage leading to Homo sapiens occurred exclusively in North Africa," Hublin said, "the [new] Moroccan fossils strongly suggest that populations close to the divergence between the Homo sapiens lineage and those leading to Neanderthals and Denisovans were present there at that time."

John Hawks, a biological anthropologist at the University of Wisconsin-Madison who was not involved in the study, agreed with the researchers' conclusions.

"It's clear from the new study that these fossils don't fit easily into the variation of Homo erectus in some ways," Hawks told Live Science. "It's likely that they're close to the common ancestor that gave rise to Neanderthals, Denisovans and modern people."

But it's unclear what the Thomas Quarry fossils should be called. "In my way of thinking, they might be the earliest fossils that we should really call Homo sapiens," Hawks said.

Hublin is hesitant to classify the fossils as a particular species or population, particularly because there are only a handful of fragmentary remains from Thomas Quarry. "Palaeoproteomic analyses are planned and could potentially help to elucidate the relationships between the European and North African fossils," Hublin said.

Human evolution quiz: What do you know about Homo sapiens?

The group had traveled for thousands of miles, crossing Africa and the Middle East until finally reaching the dimly lit forests of the new continent. They were long-vanished members of our modern human tribe, and among the first Homo sapiens to enter Europe.

There, these people would likely have encountered their distant cousins: Neanderthals.

These small bands of modern-human relatives had hooded brows, large heads and squat bodies, and they had spent epochs acclimating to Europe's colder climate. At several points across millennia, these two forms of humanity would meet, mingle and mate.

Tens of thousands of years later, these ancient encounters have left traces in the genetic code of billions of humans alive today. The lingering genes affect us in ways large and small, from our appearance to our risk of disease.

"In some places in our genome, we're more Neanderthal than we are human," Joshua Akey, a professor of integrative genomics at Princeton University, told Live Science.

These were our closest human relatives, and this is their legacy.

The first encounter

By 75,000 years ago, but possibly up to 250,000 years ago, the ancestors of most modern Eurasians first ventured out of Africa and into Eurasia. Here, modern humans came face-to-face with Neanderthals, who last shared a common ancestor with modern humans hundreds of thousands of years earlier and had been living in these continents ever since. On multiple occasions over the millennia, the groups interbred.

Related: Could Neanderthals talk?

At first, modern humans inherited whole chromosomes from Neanderthals, Sriram Sankararaman, a professor of computer science, human genetics and computational medicine at UCLA, told Live Science. However, from generation to generation, via a process known as genetic recombination, these stretches of DNA were broken up and shuffled around.

Neanderthal DNA was generally "deleterious" to modern humans, meaning it was rapidly weeded out of modern humans' DNA through evolution. This resulted in "deserts of Neanderthal DNA," or large regions of the modern human genome lacking it, Sankararaman said. For instance, scientists think the Y chromosome in males doesn't contain any Neanderthal genes. It may be that genes on the Neanderthal Y were incompatible with other human genes or they may have been randomly lost via a process known as genetic drift.

In people who inherited Neanderthal DNA, the X-chromosome also contains a lot less Neanderthal ancestry than other, non-sex chromosomes carry. This is probably because any harmful or nonfunctional mutations on the X chromosome will be expressed in males, because they lack a matching, functional copy of the gene to compensate. That likely created strong evolutionary pressure to remove such harmful Neanderthal genes from the modern human X, Emilia Huerta-Sanchez, an associate professor of ecology, evolution, and organismal biology at Brown University, told Live Science.

But some Neanderthal DNA helped modern humans survive and reproduce, and thus it has lingered in our genomes. Nowadays, Neanderthal DNA occupies, on average, 2% of the genomes of people outside Africa. However, the frequency of Neanderthal DNA that codes for beneficial traits may be as high as 80% in some regions of the genome, Akey said.

Our physical appearance

For many people, the legacy of Neanderthals is apparent in a highly visible feature: skin color.

A Neanderthal gene variant on chromosome 9 that influences skin color is carried by 70% of Europeans today. Another Neanderthal gene variant, found in most East Asians, regulates keratinocytes, which protect the skin against ultraviolet radiation via a dark pigment called melanin.

Neanderthal gene variants are also associated with a greater risk of sunburn in modern humans. Likewise, around 66% of Europeans carry a Neanderthal allele linked to a heightened risk of childhood sunburn and poor tanning ability.

Neanderthals had spent millennia at higher latitudes with less direct sun exposure, which is needed for vitamin D production. Therefore, changes to hair and skin biology may have allowed modern humans to quickly capitalize on lower levels of sunlight while still producing enough vitamin D to be healthy, John Capra, an evolutionary geneticist at Vanderbilt University, told Live Science.

"One of the cool things about interbreeding is that instead of waiting for new beneficial mutations to arise, which is a really slow process, you introduce a ton of genetic variation at once," essentially fast-tracking evolution, Huerta-Sanchez said.

Related: What's the difference between Neanderthals and Homo sapiens?

In addition, our ancestors had to adapt to colder Eurasian weather. To do so, they may have acquired Neanderthal genes that affected face shape. In a 2023 study, scientists discovered that modern humans inherited tall-nose genes from Neanderthals. A taller nose may have allowed more cold air to be heated to body temperature in the nose before reaching the lungs, suggested Kaustubh Adhikari, co-senior study author and a statistical geneticist at University College London.

The clock that makes our cells tick

Neanderthal DNA also may have helped H. sapiens adjust to the bigger differences in day and night length at northern latitudes.

Lingering Neanderthal genes affect our circadian clock, which regulates internal processes such as body temperature and metabolism. For instance, some early risers can thank Neanderthals for their circadian clock genes, Capra and colleagues found.

This may have helped our ancestors adapt to shorter winter days farther from the equator, Capra said.

"It seems like it's not that being a morning person is what matters," Capra said. "It's that that's a signal of how essentially flexible your clock is and how able it is to adapt to the variation in light-dark cycles with seasons," he said.

Our internal defenses

Many of the strongly retained Neanderthal genes are tied to immune function.

By the time H. sapiens arrived in Europe, Neanderthals had already spent hundreds of thousands of years fighting infections specific to Eurasia. By mating with Neanderthals, modern humans got an instant infusion of those infection-fighting genes.

"Those pieces of Neanderthal DNA, especially the immune ones, that were already adapted against pathogens that Neanderthals had been living with for a long time started to rise in frequency under natural selection in modern human populations," David Enard, an assistant professor of ecology and evolutionary biology at the University of Arizona, told Live Science.

While many of the ancestral pathogens that sickened ancient humans are lost to time, some of the Neanderthal genes that helped fight them off still work against modern pathogens. For example, a 2018 study by Enard and a colleague revealed that modern humans inherited Neanderthal DNA that helped them combat RNA viruses, a group that today includes the flu (influenza), HIV and hepatitis C.

Related: 10 unexpected ways Neanderthal DNA affects our health

The darker side of Neanderthal DNA

Some of the Neanderthal genes that once helped our ancestors may be harmful in the modern world.

For the most part, Neanderthal genes are not strongly expressed in the brain, which hints that they were strongly selected against during evolution. Neanderthal genes have been linked to mood disorders such as depression and to brain signaling pathways that make people more likely to become addicted to nicotine.

And even the immune boost from Neanderthals may have a downside. In 2016, scientists discovered that Neanderthal genes that prime the immune system to fight pathogens may also predispose people to allergic diseases. In addition, Neanderthal genes have been tied to a higher risk of developing autoimmune diseases, such as Graves' disease, caused by an overactive thyroid; and rheumatoid arthritis, which inflames the joints and even "Viking disease," in which one or more fingers become bent or frozen.

One Neanderthal gene variant may have made us more likely to have a severe case of COVID-19. That variant, found on chromosome 3, is found in half of South Asians and one-sixth of Europeans. But even there, the picture is complicated, as other Neanderthal genes, carried by up to half of people in Eurasia and the Americas, are associated with a reduced risk of severe COVID-19.

"Unfortunately, there are no diseases we can really say, or even traits in general, we can say, 'Oh, you can blame your Neanderthal DNA for that,'" Capra said.

That's especially true for some of the biggest health ailments, such as heart disease and cancer, where dozens or hundreds of genes, along with myriad environmental factors, affect your risk of disease.

What lies ahead

So how long will the traces of these long-lost humans linger in our genomes? Over hundreds of thousands of years, some of these Neanderthal fragments will gradually be eliminated from our genomes. Others will become firmly embedded, Akey said.

In the meantime, there's still much more to learn about how Neanderthals left their mark on us.

"Being able to leverage new genomic technology like CRISPR and gene editing is going to play an important role in understanding the actual underlying biology of how Neanderthal sequences contribute to human traits and diseases," Akey said.

Deciphering what these genes actually do could aid the development of treatments for certain conditions, he said.

And the gene flow wasn't one-way; scientists are also trying to determine how modern-human DNA may have influenced Neanderthals and are applying artificial intelligence (AI) methods to ancient genomes to create a more detailed picture of what our long-lost cousins were like.

Figuring out the role of Neanderthal DNA in our genomes does more than help us understand our health. These bits of DNA can provide clues as to what makes us unique, Sankararaman said.

"Neanderthal DNA entered our genomes at an important time in our history," Sankararaman said, when our ancestors were moving into new environments.

"By looking at the fate of these bits of DNA," he said, "we can hope to understand what were the functionally important regions in our genome over this period of time."

Editor's Note: This story was originally published in March 2024.

Neanderthals have fascinated scientists since they were first discovered in the 19th century. Their long heads and low brow ridges initially convinced experts that Neanderthals were some kind of evolutionary wrong turn that ended up in European caves.

It took more than a century for researchers to prove that Neanderthals were actually quite intelligent and that they interbred with modern humans (Homo sapiens). The number of discoveries related to Neanderthals' biology and culture has skyrocketed in recent years — and 2025 was a noteworthy year. While we learned that Neanderthals had biological features that were strikingly different from modern humans', this year's discoveries also showed that some aspects of their behavior and culture were similar to ours.

Here are 10 major Neanderthal findings from 2025 — and what they teach us about our own evolution.

1. Neanderthals were the first to make fire.

The hottest — but also somewhat controversial — Neanderthal discovery of the year was that the first humans to make and control fire were Neanderthals living in England more than 400,000 years ago.

In December, researchers announced that they had found reddened clay and heat-shattered flint hand axes at an archaeological site in Suffolk. But the smoking gun was the discovery of tiny flakes of pyrite, a mineral that produces sparks when struck against flint.

Experts have debated for decades whether early human ancestors deliberately made fire or whether they opportunistically used wildfires that sprang up. The combination of flakes of pyrite and charred soil and tools points to Neanderthals' purposeful creation of fire.

The discovery, however, does not tell us whether Neanderthals invented this technology or they learned it from even earlier ancestors, such as Homo erectus. Regardless, the fire evidence shows that Neanderthals were smart enough to figure out how to survive in cold and dark European climates.

2. Neanderthals cannibalized women and children.

Around 45,000 years ago — very close to when Neanderthals disappeared forever — six members of a Neanderthal group were cannibalized, according to a study published in November. Their remains were discovered in the Goyet cave system in Belgium with butchery marks similar to those on animal bones.

This isn't the first time archaeologists have found evidence of cannibalism in Neanderthals. But it is the best evidence experts have to suggest one group — probably Neanderthals but possibly modern humans — deliberately targeted the women and children of another group, perhaps as a way to eliminate the group's reproductive potential.

3. A Neanderthal left the world's oldest fingerprint.

A curious-looking rock found in Spain contains the world's oldest known fingerprint, and it was probably made by a Neanderthal using ocher 43,000 years ago, researchers announced in May.

The team investigating the rock, which is the size of a large potato, thinks that it has face-like features and that the red dot may be a nose. If they're correct, it would mean Neanderthals were creating symbolic art, which could settle a decades-long debate in paleoanthropology.

Not all experts agree that the rock is an early version of Mr. Potato Head, but they do think the fingerprint and its characteristic whorl pattern represent a clear example of Neanderthals' use of red ocher pigment.

4. Neanderthals may have used "crayons."

Scientists in Crimea found three pointy chunks of red and yellow ocher that Neanderthals may have used as early "crayons" 100,000 years ago, according to research published in November.

The hunks of mineral appear to have been repeatedly sharpened, which suggested to the researchers that the ocher was used for culturally meaningful purposes rather than in practical tasks, such as tanning hides.

Although ocher has been found at other Neanderthal sites, not all experts are convinced of the crayon interpretation. Instead, they suggest Neanderthals may have scraped powder from the ocher chunks for another purpose, such as to leave a fingerprint.

5. Neanderthals were low-energy.

In July, researchers discovered that a key Neanderthal gene variant that is still found in some humans today could be detrimental to athletic performance because it limits the body's ability to produce energy during intense exercise.

Researchers found that the Neanderthal version of an enzyme called AMPD1 was different from the one in most modern humans. The Neanderthal enzyme variant allowed adenosine monophosphate (AMP) to build up in their muscles rather than being quickly removed. This AMP buildup is problematic because it makes it harder to produce adenosine triphosphate (ATP), a molecule that the body uses to store energy.

Modern humans who carry the Neanderthal variant of the gene have a lower probability of achieving elite athletic status, the researchers found. But while the Neanderthal variant may have affected their muscle metabolism slightly, it may not have contributed to their extinction.

6. Neanderthals were more susceptible to lead poisoning compared with humans.

In a study published in October, researchers examined 51 teeth from H. sapiens, Neanderthals and other ancestors for evidence of lead exposure. Lead occurs naturally in our environment, but it is known to be toxic at high levels, causing damage to the brain and other organs. Researchers discovered that human ancestors were affected by episodic lead exposure for nearly 2 million years — and that human brains may have evolved some protection against lead poisoning.

Humans living today have a unique version of a gene called NOVA1 that is important for brain development and language skills. The gene also appears to confer greater resistance to lead than other versions of the gene do, such as the one in our Neanderthal cousins.

Therefore, researchers propose, the modern-human version of NOVA1 may have given us a slight advantage over Neanderthals and may have contributed to the demise of the Neanderthals.

7. Neanderthals had a "fat factory" in Germany.

Neanderthals primarily ate meat (and maggots), which put them at risk of developing protein poisoning, a lethal condition that results from eating too much protein and too few fats and carbohydrates.

But in July, researchers announced their discovery of a "fat factory" that Neanderthals may have used to stave off this condition 125,000 years ago. Their survey of nearly 200 animal bones revealed that Neanderthals smashed the bones to get at the marrow inside, which they boiled to extract the fat.

Fat is high in calories, and Neanderthals may have saved it to eat during food shortages. This innovative food-collection method is similar to what some ancient modern-human foraging groups did, suggesting that, in at least one way, Neanderthals were similar to us.

8. Neanderthals lacked a key DNA-synthesizing gene.

In August, researchers investigating the enzyme adenylosuccinate lyase (ADSL) found that the version in Neanderthals was more active than the one in humans. ADSL helps synthesize purine, which is one of the fundamental building blocks of DNA, and an ADSL deficiency is known to result in intellectual disability in modern humans. So researchers modified mice to have a modern-human-like ADSL gene and found that they were better at completing a task to get water.

But even though ADSL deficiency can cause intellectual and behavioral problems in modern-day people, it's not yet clear whether the Neanderthal variant impaired them.

9. Our cousins suffered a population bottleneck.

Even before Neanderthals disappeared forever, their numbers were dwindling because of a population bottleneck, according to research published in February.

Scientists looked at the tiny inner-ear bones of Neanderthals from various time periods and noticed that, around 110,000 years ago, there was an abrupt decline in the diversity of bone shapes. This decline suggests a bottleneck event, when a species undergoes a sudden reduction in variation due to factors such as genocide or climate change.

While the ear bones alone didn't cause the Neanderthals' downfall, the bottleneck may have been the beginning of the end.

10. Neanderthals' blood may have doomed them.

Biologically, Neanderthals had distinct blood variants that separated them from modern humans — and two of those variants we learned about this year may have hastened our ancient cousins' extinction.

In January, researchers discovered that Neanderthals had a rare blood type that may have been fatal to their offspring when they mated with Denisovans or early H. sapiens.

Neanderthals carried a variation of the blood antigen Rh, which gives the positive and negative signs to blood types. Before modern medical interventions, if someone who was Rh-negative was pregnant with a fetus that was Rh-positive, it caused a miscarriage or stillbirth. The researchers found that, if a Neanderthal female mated with a H. sapiens or Denisovan male, there would have been a high risk of anemia, brain damage and infant death. And that might have spelled the end of the line for Neanderthals.

Another study published in October suggested that a fatal red blood cell incompatibility between Neanderthals and humans also contributed to our ancient cousins' extinction. Researchers focused on the PIEZO1 gene that affects oxygen transportation in red blood cells. Neanderthals' version of this gene essentially let their blood cells trap oxygen efficiently, while the modern-human version more efficiently released oxygen to tissues. When maternal oxygen isn't passed on to the fetus, it can restrict the growth of the fetus or lead to miscarriage. So, if a hybrid Neanderthal-human mother mated with a modern-human father or with a hybrid Neanderthal-human father, their offspring would be more likely to die than the offspring of non-hybrids.

Although Neanderthals' extinction likely did not hinge on any one specific gene variant, the new research into red blood cells and maternal-fetal incompatibility is providing key insight into the demise of our archaic cousins around 35,000 years ago.

Neanderthal quiz: How much do you know about our closest relatives?

Our understanding of how our species evolved has improved dramatically since we first began analyzing ancient DNA. This year, researchers made impressive discoveries across 3 million years of human evolution, most of which relied on DNA, genomic or proteomic analyses.

Here are 10 major findings about human ancestors and our close ancient relatives that scientists announced in 2025.

1. Two new species of human relatives were discovered in Ethiopia.

A handful of teeth found at the Ledi-Geraru site in Ethiopia suggest that diverse species of human relatives unlike any seen before were roaming the area 2.6 million years ago.

In August, researchers announced the discovery of 13 teeth. Ten are estimated to be 2.63 million years old and don't belong to either Australopithecus afarensis or Australopithecus garhi, the two australopithecine species known from the area. Because the teeth don't have any especially unique features and aren't in a skull, the newfound species they may come from does not have an official name. Researchers are calling it the Ledi-Geraru Australopithecus.

In the same study, the researchers found two teeth that are 2.59 million years old and one that is 2.78 million years old. All of them seem to belong to the genus Homo, which would make them some of the earliest remains of our own genus.

The dental discoveries mean that at least three archaic human relatives were living in this region of Ethiopia around 2.5 million years ago.

2. Imported stone tools show our relatives were much smarter than we thought.

Hundreds of stone tools discovered in Kenya revealed that our ancient relatives had a high degree of forward planning 600,000 years earlier than experts previously thought.

In an August study, researchers looked at more than 400 stone tools from the site of Nyayanga dated to 3 million to 2.6 million years ago. The tools were likely not made by our genus. While the tools were fairly basic — flakes chipped off of a larger stone — the stones used to make them came from locations more than 6 miles (9.7 kilometers) away.

The fact that hominins were transporting stones from far away to make tools suggests an excellent ability to plan ahead, long before our genus Homo arose.

3. Earliest evidence of Homo erectus found in Georgia

In July, researchers announced the discovery of a 1.8 million-year-old jawbone from Homo erectus at the site of Orozmani in the Republic of Georgia. In 2022, the paleoanthropologists had found a single tooth that they thought was from H. erectus, and the jawbone discovered this year clinched the identification.

H. erectus was our direct ancestor and evolved around 2 million years ago in Africa. It was also the first human ancestor to leave Africa, and eventually ended up in parts of Europe, Asia and Oceania.

To date, the earliest evidence of H. erectus outside Africa comes from Orozmani and a second site in Georgia called Dmanisi, suggesting human ancestors settled in the Caucasus region shortly after leaving Africa.

4. A mystery human reached Indonesia 1.5 million years ago.

Stone tools discovered on the Indonesian island of Sulawesi this year suggest that either H. erectus or an unknown human relative reached Oceania nearly 1.5 million years ago. This matches up well with previous evidence that H. erectus arrived on the island of Java around 1.6 million years ago.

But because no ancient skeletal remains have been found on Sulawesi yet, researchers are unsure if the toolmaker was indeed H. erectus. Another candidate could be H. floresiensis, the diminutive "hobbit" species, which has been found on the neighboring island of Flores. Some researchers think the hobbits originally came from Sulawesi.

Additional excavation on Sulawesi may eventually clarify which species called the island home.

5. Humans arrived in Australia 60,000 years ago.

Genetic research published in November showed that Homo sapiens reached Australia 60,000 years ago, likely via two different routes through the Western Pacific. This finding appears to settle a long-standing debate about humans' arrival on the continent — a feat that required expert knowledge of watercraft and sailing.

The new DNA evidence supports archaeological evidence, including stone tools and pigments on cave walls, of a "long chronology" in which the first arrivals showed up around 60,000 to 65,000 years ago.

But not everyone is convinced. In a July study, researchers used the fact that some Indigenous Australians have Neanderthal DNA to suggest that Australia wasn't populated until about 50,000 years ago — an idea known as the "short chronology."

More research into the origins of the earliest Australians is forthcoming.

6. Drought may have doomed the "hobbits."

By 50,000 years ago, H. floresiensis seems to have disappeared from Flores. In December, researchers published a study suggesting that drought may have fueled their demise.

While studying the rainfall on Flores, scientists discovered that it declined considerably between about 76,000 and 61,000 years ago and that the population of an elephant relative called Stegodon, which the hobbits hunted, disappeared around 50,000 years ago.

The researchers think decreased rainfall led to the reduction in the Stegodon population, which made life more difficult for the hobbits. And if modern humans also reached Flores — perhaps part of the wave of people who eventually settled Australia — the pressure of competition from another species may have wiped out H. floresiensis.

7. Denisovans got a face.

Our extinct relatives the Denisovans were first discovered in 2010 based on DNA extracted from a tiny finger bone. But until this year, no one knew what a Denisovan skull looked like.

Researchers debated for years what species the thick jawbone, recovered off the coast of Taiwan in 2000, came from, with some suggesting H. erectus and others suggesting H. sapiens. But using paleoproteomic analysis, researchers announced in May that the jawbone was from a male Denisovan.

Ancient proteins also revealed in June that a skull discovered in China in 1933, called the "Dragon Man," is from a Denisovan, finally putting a face to the name. But while Dragon Man has now been slotted into the story of human evolution, it is not yet clear whether the group should be considered a separate species, Homo longi.

And in September, researchers reconstructed a 1 million-year-old squashed skull from China and suggested that it may have been a Denisovan ancestor rather than H. erectus.

These three discoveries are pointing paleoanthropologists to clues about the origins and spread of the mysterious Denisovans — a task that will surely continue in the coming years.

8. Denisovan DNA helped Native Americans survive.

Researchers announced in August that some people with Indigenous American ancestry carry Denisovan genes, likely passed on through Neanderthals who mated with modern humans.

In looking at a protein-coding gene called MUC19, scientists discovered that 1 in 3 Mexicans alive today has a version of the gene similar to Denisovans' and that it likely "hitched a ride" from Neanderthals. Essentially, Neanderthals got the gene from mating with Denisovans and then passed it along when they mated with humans. This is the first time scientists have found a Denisovan gene in humans that came via Neanderthals.

Exactly what the Denisovan variant of the MUC19 gene does is currently unclear, but the researchers think it must have been beneficial to the earliest Americans for it to be preserved in the human genome.

9. Interbreeding was rampant among our archaic relatives.

The story of human evolution has gotten wonderfully messy since the genomic revolution. DNA and protein analyses have revealed new groups like the Denisovans, as well as the mating of Neanderthals, modern humans and Denisovans. But this year brought a few surprise pairings as well.

In August, researchers announced that a handful of 300,000-year-old teeth suggested humans and H. erectus may have interbred in China. The teeth had an unusual combination of ancient features, like thick molar roots, and modern features, like small wisdom teeth, that could mean two different species were sharing their genes.

Researchers announced in March that Neanderthals, modern humans and a mysterious third lineage lived alongside one another in caves in what is now Israel around 130,000 years ago. The Homo groups may have mixed and mingled for 50,000 years, potentially sharing cultural practices in addition to genetic material.

And in November, a DNA study of humans' arrival in Australia suggested that, along the way, these early human pioneers likely interbred with one or more archaic human groups, such as H. longi, Homo luzonensis or H. floresiensis.

Although we can see genetic differences among these groups using 21st-century technology, perhaps our earliest ancestors simply saw Neanderthals, Denisovans and others as fellow humans.

10. Most Europeans had a dark complexion until 3,000 years ago.

In a study published in July, scientists found that the genes for lighter skin, lighter hair and lighter eyes emerged among Europeans only about 14,000 years ago and that, until 3,000 years ago, most Europeans had dark skin, hair and eyes.

The researchers determined this from 348 samples of ancient DNA from archaeological sites spread throughout Western Europe and Asia. The first humans to reach Europe around 50,000 years ago carried genes for dark complexions. Once lighter traits emerged, they appeared only sporadically in the genetic data until fairly recently. By about 1000 B.C., those lighter traits became widespread in Europe.

Whether lighter skin, hair and eyes had any sort of evolutionary advantage for early Europeans is still unclear, though.

Human evolution quiz: What do you know about Homo sapiens?

The last two decades have seen a revolution in scientists' ability to reconstruct the past. This has been made possible through technological advances in the way DNA is extracted from ancient bones and analyzed.

These advances have revealed that Neanderthals and modern humans interbred — something that wasn't previously thought to have happened. It has allowed researchers to disentangle the various migrations that shaped modern people. It has also allowed teams to sequence the genomes of extinct animals, such as the mammoth, and extinct agents of disease, such as defunct strains of plague.

While much of this work has been carried out by analyzing the physical remains of humans or animals, there is another way to obtain ancient DNA from the environment. Researchers can now extract and sequence DNA (determine the order of "letters" in the molecule) directly from cave sediments rather than relying on bones. This is transforming the field, known as paleogenetics.

Caves can preserve tens of thousands of years of genetic history, providing ideal archives for studying long-term human–ecosystem interactions. The deposits beneath our feet become biological time capsules.

It is something we are exploring here at the Geogenomic Archaeology Campus Tübingen (GACT) in Germany. Analyzing DNA from cave sediments allows us to reconstruct who lived in ice age Europe, how ecosystems changed and what role humans played. For example, did modern humans and Neanderthals overlap in the same caves? It's also possible to obtain genetic material from faeces left in caves. At the moment we are analyzing DNA from the droppings of a cave hyena that lived in Europe around 40,000 years ago.

The oldest sediment DNA discovered so far comes from Greenland and is 2 million years old.

Paleogenetics has come a long way since the first genome of an extinct animal, the quagga, a close relative of modern zebras, was sequenced in 1984. Over the past two decades, next-generation genetic sequencing machines, laboratory robotics and bioinformatics (the ability to analyze large, complex biological datasets) have turned ancient DNA from a fragile curiosity into a high-throughput scientific tool.

Today, sequencing machines can decode up to a hundred million times more DNA than their early predecessors. Where the first human genome took over a decade to complete, modern laboratories can now sequence hundreds of full human genomes in a single day.

In 2022, the Nobel prize in physiology or medicine was awarded to Svante Pääbo, a leading light in this field. It highlighted the global significance of this research. Ancient DNA now regularly makes headlines, from attempts to recreate mammoth-like elephants, to tracing hundreds of thousands of years of human presence in parts of the world. Crucially, advances in robotics and computing have allowed us to recover DNA from sediments as well as bones.

GACT is a growing research network based in Tübingen, Germany, where three institutions collaborate across disciplines to establish new methods for finding DNA in sediments. Archaeologists, geoscientists, bioinformaticians, microbiologists and ancient-DNA specialists combine their expertise to uncover insights that no single field could achieve alone —- a collaboration in which the whole genuinely becomes greater than the sum of its parts.

The network extends well beyond Germany. International partners enable fieldwork in archaeological cave sites and natural caves all over the world. This summer, for example, the team investigated cave sites in Serbia, collecting several hundred sediment samples for ancient DNA and related ecological analyses. Future work is planned in South Africa and the western United States to test the limits of ancient DNA preservation in sediments from different environments and time periods.

A needle in a haystack

Recovering DNA from sediments sounds simple: take a scoop, extract, sequence. In reality, it is far more complex. The molecules are scarce, degraded and fragmented, and mixed with modern contamination from cave visitors and wildlife. Detecting authentic ice age molecules relies on subtle chemical damage patterns to the DNA itself, ultra-clean laboratories, robotic extraction, and specialized bioinformatics. Every positive identification is a small triumph, revealing patterns invisible to conventional archaeology.

Much of GACT's work takes place in the caves of the Swabian Jura within Unesco World Heritage sites such as Hohle Fels, home to the world's oldest musical instruments and figurative art. Neanderthals and Homo sapiens left behind stone artifacts, bones, ivory and sediments that accumulated over tens of millennia. Caves are natural DNA archives, where stable conditions preserve fragile biomolecules, enabling researchers to build up a genetic history of ice age Europe.

One of the most exciting aspects of sediment DNA research is its ability to detect species long gone, even when no bones or artifacts remain. A particular focus lies on humans: who lived in the cave, and when? How modern humans and Neanderthals use the caves and, as mentioned, were they there at the same times? Did cave bears and humans compete for shelter and resources? And what might the microbes that lived alongside them reveal about the impact humans had on past ecosystems?

Sediment DNA also traces life outside the cave. Predators dragged prey into sheltered chambers, humans left waste behind. By following changes in human, animal and microbial DNA over time, researchers can examine ancient extinctions and ecosystem shifts, offering insights relevant to today's biodiversity crisis.

The work is ambitious: using sedimentary DNA to reconstruct ice age ecosystems and to understand the ecological consequences of human presence. Only two years into GACT, every dataset generates new questions. Every cave layer adds another twist to the story.

With hundreds of samples now being processed, major discoveries lie ahead. Researchers expect soon to detect the first cave bear genomes, the earliest human traces, and complex microbial communities that once thrived in darkness. Will the sediments reveal all their secrets? Time will tell — but the prospects are exhilarating.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Neanderthals were the world's first innovators of fire technology, tiny specks of evidence in England suggest. Flecks of pyrite found at a more than 400,000-year-old archaeological site in Suffolk, in eastern England, push back archaeologists' evidence for controlled fire-making and suggest that key human brain developments began far earlier than previously thought.

"We're a species who've used fire to really shape the world around us," study co-author Rob Davis, a Paleolithic archaeologist at the British Museum, said in a news conference on Tuesday (Dec. 9). "The ability to make fire would have been critically important" in human evolution, Davis said, "accelerating evolutionary trends" such as developing larger brains, maintaining larger social groups, and increasing language skills.

Since 2013, Davis and colleagues have been excavating an archaeological site in England called Barnham, which yielded stone tools, burnt sediment and charcoal from 400,000 years ago. In a study published Wednesday (Dec. 10) in the journal Nature, the researchers revealed that the site contained the world's earliest direct evidence of fire-making — and that this fire technology was likely pioneered by Neanderthals.

A big turning point

Barnham was first recognized as a Paleolithic human site in the early 1900s due to the presence of stone tools. But recent excavations uncovered evidence of ancient human groups occupying the area more than 415,000 years ago, when Barnham was a small, seasonal watering hole in a woodland depression.

In one corner of the site, archaeologists found a concentration of heat-shattered hand axes as well as a zone of reddened clay. Through a series of scientific analyses, the researchers discovered that the reddened clay had been subjected to repeated, localized burning, which suggested the area may have been an ancient hearth.

"The big turning point came with the discovery of iron pyrite," study co-author Nick Ashton, curator of Paleolithic collections at the British Museum, said in the news conference.

Pyrite, also known as fool's gold, is a naturally occurring mineral that can produce sparks when struck against flint. While pyrite is found in many locations around the world, it is extremely rare in the Barnham area, meaning someone specifically brought pyrite to the site, probably with the aim of making fire, the researchers said in the study.

Humans' use of fire

Because of the importance of controlled fire, paleoanthropologists have long debated the timing of this invention.

"There are so many obvious advantages to fire, from cooking to protection from predators to its technological use in creating new types of artifacts to its ability to bring people together," April Nowell, a Paleolithic archaeologist at the University of Victoria in Canada who was not involved in the study, told Live Science in an email. "We only have to think of our own childhoods gathering around a campfire to understand its emotional resonance."

Researchers believe that early humans first used wildfires for cooking food. This was a crucial step in human evolution because cooking widened the range of food available and made it more digestible, which in turn provided more nutrients needed to grow a larger brain, Davis said.

But there is limited evidence for deliberate early fire technology, and that evidence is often ambiguous, the researchers noted in the study.

For example, scientists unearthed reddened sediment at Koobi Fora in Kenya that dated to about 1.5 million years ago. Researchers suggested it could hint at early fire use because the key hominin at the site — Homo erectus — had a fairly large brain. And at two sites in Israel dated to about 800,000 years ago, burnt animal bones and stone tools suggest possible control of fire by the human ancestors who lived there.

Fire technology then exploded around 400,000 years ago. Archaeologists have found evidence of burning at cave sites in France, Portugal, Spain, Ukraine and the U.K., and then more widespread use of fire in Europe, Africa and the Levant (the region around the east Mediterranean) by 200,000 years ago.

But these previous examples do not show the same kind of conclusive geochemical evidence of fire making that was found at Barnham, Ashton argued. He called the team's careful analysis of the Barnham sediment and identification of pyrite "the most exciting discovery in my 40-year career."

Neanderthals are "fully human"

However, any bones at Barnham have since disintegrated, so the "smoking gun" of butchered and burned animal bones that could prove the site was used for cooking has not been found.

This also means there are no skeletal remains of the fire producers themselves at Barnham — but study co-author Chris Stringer, a paleoanthropologist at the National History Museum in London, has a guess about their identity.

"We assume that the fires at Barnham were being made by early Neanderthals," Stringer said in the news conference, based on a nearby site called Swanscombe, where Neanderthal skull bones were discovered that dated to the same time period as Barnham.

While experts have known for about a decade that some Neanderthals could make fire, that evidence goes back only 50,000 years. The Barnham finds push that date 350,000 years further back, suggesting Neanderthals were much smarter than most people give them credit for.

Neanderthals "are fully human," Stringer said. "They have complex behavior, they're adapting to new environments, and their brains are as large as ours. They're very evolved humans."

Nowell said that the study's results add fuel to a larger debate about Neanderthals' control of fire and their social and cultural use of it.

"There is a lot of discussion right now about whether all Neanderthals made fire or if it is only some Neanderthals at some times and places that made fire," Nowell said. The new study "is another important data point in our understanding of Neanderthal pyrotechnical capabilities with all that implies cognitively, socially and technologically."

Who made fire first?

If the researchers are correct that Neanderthals made fire from flint and pyrite more than 400,000 years ago in England, this raises additional questions, Nowell said.

"Despite its obvious advantages, questions remain about the nature of early fire use: When did fire use become a regular part of the human behavioral repertoire? Were early humans dependent on the opportunistic use of wildfires and lightning strikes? Was fire rediscovered multiple times?" Nowell said.

The ancestors of Homo sapiens were living in Africa 400,000 years ago and not likely interacting with early Neanderthals half a world away.

"We don't know if Homo sapiens at that date had the ability to make fire," Stringer said, because to date there is no clear evidence for control of fire any earlier than Barnham.

This means that Neanderthals may have invented ways to make and control fire somewhere in continental Europe, which then enabled our human cousins to move further north into England, heating and lighting their way with fire.

"It's plausible that fire became more controlled in Europe and spread to Africa," Ashton said. "We have to keep an open mind."

Neanderthal quiz: How much do you know about our closest relatives?

While analyzing hundreds of Neanderthal bone fragments from a cave in Belgium, archaeologists discovered a horrifying secret: Six Neanderthals had been cannibalized 45,000 years ago, and the cannibals preferred to eat the women and children first.

Modern archaeologists first explored the Goyet cave system in the Wallonia region of southern Belgium in the late 19th century. Excavators discovered 101 Neanderthal bone fragments, many of which had butchery marks similar to those on animal bones, suggesting someone had killed and eaten them.

In a new study published Nov. 19 in the journal Scientific Reports, researchers dug into the biological profile of the collection of fragments and determined that all of the butchered Neanderthals were small female adults and children.

"We cannot determine exactly why these individuals were targeted, but the composition of the assemblage — four adult females and two immature individuals — is too specific to be accidental," Quentin Cosnefroy, a biological anthropologist at the University of Bordeaux, France, and lead author of the study, told Live Science in an email.

To reach this conclusion, the researchers first reassembled the butchered bones as much as possible, finding that the large collection of fragments constituted at least six Neanderthals. Based on genetic analysis, the researchers determined that four of the Neanderthals were female adults or adolescents and two were male children, and that the females were not related to one another. The female Neanderthals' bones also showed that they were shorter and more lightly built than the average Neanderthal female.

All of this evidence was combined with a previous isotopic study that had revealed that all of the cannibalized Neanderthals at Goyet were born in a completely different region than where they died but shared a similar diet. (Isotopes are variations of elements found in the environment and water, and they end up in bones and teeth. This allows researchers to determine where ancient people or animals lived, as different places have different isotopic signatures.)

The evidence gathered from the Goyet Neanderthal bones adds up to "exocannibalism" — cannibalism of one group by a different group, according to the researchers.

"At a minimum," the researchers wrote in the study, "it suggests that weaker members of one or multiple groups from a single neighbouring region were deliberately targeted" and that the cannibals might have specifically sought to undermine the reproductive potential of a competing group.

"These individuals may have come from different populations, implying that the cannibalism at Goyet could represent multiple events involving different groups over time," Cosnefroy said, or they may have "belonged to the same group and were killed during a single event."

But it is currently unclear whether the cannibals were Neanderthals or early Homo sapiens, who were likely present in the area at the same time as the Neanderthals.

The researchers suggested, however, that cannibalism among early H. sapiens is usually seen in connection with funeral rituals, while evidence of survival cannibalism has been seen in Neanderthal sites in France and Croatia. This means the bones at Goyet represent "the most compelling evidence to date for inter-group competition among Late Pleistocene Neanderthal populations."

The Neanderthals whose bones were found in the Goyet cave were among the last Neanderthals in Europe at a time when H. sapiens had begun to encroach on their territory. A previously isolated Neanderthal group happening upon another Neanderthal group may have resulted in lethal intergroup tension, the researchers wrote, particularly if they saw each other as enemies.

In a period marked by Neanderthal cultural diversity, biological decline, and the arrival of H. sapiens in Northern Europe, the cannibalized Neanderthal females and children are likely the unfortunate result of the mistreatment of outsiders, the researchers concluded.

The way the butchered Neanderthals ended up in the Goyet cave is still under investigation.

"Moving living people is much easier than transporting dead bodies or body parts," Cosnefory said, but the Goyet Neanderthals are represented mostly by leg bones. "This makes it plausible that the individuals were brought alive, killed close to the Goyet cave, and that the cannibalizing group deposited only selected body parts inside the chamber."

Neanderthal quiz: How much do you know about our closest relatives?

Neanderthals left behind various clues about their enigmatic lives. But less is known about their spiritual sides. Some archaeologists and anthropologists believe these early humans, who disappeared more than 30,000 years ago, may have engaged in what could be deemed ritualistic or sacred activities.

For instance, we know that Neanderthals buried their dead, accumulated animal skulls in caves for seemingly symbolic purposes, created rock art and etched symbolic drawings on bear bones. They also removed feathers from birds, possibly for use as adornments, and likely made use of eagle talons as pendants. At times, they engaged in cannibalism, leading to speculation among scholars as to whether it was done for ritual reasons.

All this and more hints that Neanderthals engaged in ritualistic practices. And it brings about the question: Did Neanderthals have religious beliefs?

Experts have a mix of different opinions, Live Science learned. Part of that depends on how "religion" is defined.

Definitions of "religion" vary, but often include beliefs in supernatural beings, such as deities, and organized practices done to interact with them. But were Neanderthals capable of this?

"If by 'religion' we mean ritual behaviors directed at supernatural agents then yes I believe Neanderthals were religious," Patrick McNamara, a neurology professor at Boston University's School of Medicine who has conducted extensive research into the evolution of the human brain and the neuroscience of religion, told Live Science in an email. "Their religious beliefs and behaviors were very likely close to what we call 'shamanism' — a visionary form of religious experience."

There is now "very good evidence that they practiced ritual cannibalism and that they buried their dead and that made a ritual practice — like Shamans do — of traversing deep cave environments and constructing ritual 'altars' of circular or arranged skulls," McNamara said.

The altar-like formation of arranged skulls is particularly compelling, he noted.

"I also believe that the Neanderthals practiced what we call 'Bear ceremonialism' and worshiped the Bear as a divinity," he said, noting that "there are several Neanderthal-related archaeological sites with Bear skulls arranged in ritual altars in caves etc."

Other scholars said that while Neanderthals may have had religious experiences of some kind, these would have been different from those that Homo sapiens have today. Robin Dunbar, a professor emeritus of evolutionary psychology at the University of Oxford, told Live Science in an email that "I don't think they had religious beliefs in the sense we do."

Dunbar doesn't believe that their ability to mentalize — understand the emotional state of yourself and others — would have been sophisticated enough to develop a religion in the same way that people do today, with different sets of belief systems that have their own theologies.

However, Neanderthals likely had religious experiences on some level, possibly in "experiences of mystery and magic, and a deep sense of engagement," Dunbar said. "You don't need a theology for this, but the experience is very real."

Margaret Boone Rappaport, an anthropologist who co-wrote the book "The Emergence of Religion in Human Evolution" (Routledge, 2020), told Live Science in an email that while Neanderthals "may have engaged in some forms of ritual, they likely did not possess the specific advanced neurocognitive capacity for a complex, modern human-like religion or 'theological thinking.'"

One section of the human brain that is important for religion is the precuneus. It's an area of the brain associated with memory retrieval and how one sees and perceives the outside world, a 2006 paper published in the journal Brain noted. Religious belief also registers a larger signal in the precuneus, among other brain regions, in religious people compared with nonreligious people, a 2019 review noted.

Neanderthal brain architecture was different from that of modern-day Homo sapiens, and "the lack of expansion in the precuneus, suggests that Neanderthals did not have the cognitive abilities for the 'imagined spaces and beings' essential to human theologies," Rappaport said.

Karel Kuipers, an archaeologist and doctoral candidate at Leiden University in the Netherlands whose research focuses on Neanderthals and how we research them, said we don't know if Neanderthals had religious beliefs.

"It's very difficult to see how they viewed the world," Kuipers told Live Science. We have to be careful about assigning a spiritual context to Neanderthal behavior, he said. For instance, while people today might associate the burial of the dead with a funeral and religion, it's possible that for Neanderthals it might have just been a practical way of disposing of a decomposing body.

Editor's note: This article was updated on March 27, 2026 to note that the vast majority of Neanderthals went extinct 40,000 years ago, not 34,000 years ago as was previously stated.

Neanderthal quiz: How much do you know about our closest relatives?

The act of kissing may have started long before modern humans existed, a new modeling study suggests.

Kissing stretches back roughly 21 million years, to the shared ancestor of humans and other large apes, according to the study, published Wednesday (Nov. 19) in the journal Evolution and Human Behavior. Meanwhile, Homo sapiens likely emerged around 300,000 years ago.

The researchers also concluded that kissing most likely occurred in Neanderthals, the closest extinct relatives of modern humans, and that Neanderthals and modern humans may have kissed each other.

"This is the first time anyone has taken a broad evolutionary lens to examine kissing," study lead author Matilda Brindle, an evolutionary biologist at the University of Oxford, said in a statement. "Our findings add to a growing body of work highlighting the remarkable diversity of sexual behaviours exhibited by our primate cousins."

Model kissing

Before dating the world's oldest kisses, an international team of researchers defined what it means to kiss. This was important, because other mouth-to-mouth actions in nature look similar to kissing. For example, mother orangutans and chimpanzees transfer chewed food to their infants mouth to mouth, and fish engage in "kiss fighting" to assert dominance or compete for territory. Ultimately, the researchers defined kissing as "non-aggressive, mouth-to-mouth contact that did not involve food transfer," they wrote in the statement.

Based on this definition, various modern-day primates — including bonobos, gorillas, chimpanzees, orangutans, macaques and baboons — have been observed kissing.

The researchers then used a statistical method called Bayesian modeling to reconstruct the evolutionary history of kissing. They treated kissing as a biological trait and tested many possible ways this behavior could have evolved to see how likely it was that different ancestors also kissed. They ran the model 10 million times to make sure the results were strong and reliable.

They concluded that kissing evolved once in the common ancestor of large apes (Hominidae) sometime between about 21.5 million and 16.9 million years ago.

However, kissing was absent in ancestral Macacina and Papionina (groups that include macaques and baboons), suggesting that kissing evolved separately in the modern-day species belonging to these groups. The team determined this by extrapolating back in time from the behavior of modern-day species to that of their common ancestors.

Although more evidence is needed, the researchers said kissing might have evolved from the practice of pre-chewing and transferring food from a mother to an infant. This practical food-sharing behavior may have been repurposed into what we now recognize as kissing.

How this fits in with earlier kissing research

The finding that Neanderthals kissed not only each other but also modern humans isn't exactly news to anthropologists.

"I am not sure that the current study adds anything substantially new to our knowledge of this behavior in Neandertals," April Nowell, a Paleolithic archaeologist and professor of anthropology at the University of Victoria in British Columbia who was not involved with the study, told Live Science in an email.

But the new study does align with previous findings. Nowell noted that "intriguing evidence" came in 2017, when a different research group compared microbes preserved in the dental plaque of a Neanderthal who lived 48,000 years ago with those found in modern human mouths. The team concluded that Neanderthals and H. sapiens may have kissed each other, although the microbial overlap could also reflect shared food or water, said Nowell, who was not a part of that study.

Additionally, we already know that H. sapiens and Neanderthals mated during a roughly 7,000-year-long pulse, so it's possible that some kissing occurred when that happened assuming that some ancient mating behaviors were similar to those of today.

That said, it's unclear how widespread kissing was among our human relatives. Because kissing isn't a universal behavior among modern humans — only about half of cultures engage in it — Nowell said the same variability may have existed in the past. If Neanderthals kissed, she said, "then it might have been a behavior that some Neandertal communities engaged in while others did not."

Scientists still aren't sure why kissing persists across so many species, especially given the potential downsides, such as the spread of disease. One idea is that kissing helps individuals boost reproductive success. For example, kissing a potential partner may help people gauge a mate's quality through subtle chemical cues which can offer clues about a person's overall health, genetic compatibility, immune system, and the makeup of their oral microbiome, the researchers wrote in the new study. Researchers have also proposed that kissing strengthens social bonds and may even benefit immunity by allowing the exchange of microbes.

Neanderthal quiz: How much do you know about our closest relatives?

The ability to make art has often been considered a hallmark of our species. Over a century ago, prehistorians even had trouble believing that modern humans from the Upper Paleolithic (between 45,000 and 12,000 years ago) were capable of artistic flair.

Discoveries of uncontrovertibly old artworks from the caves and rockshelters of Europe soon dispelled their doubts. But what of the Neanderthals; an ancient, large-brained sister group to our own species? We now know that they were capable of making art too.

However, at present, all of the Neanderthal evidence is non-figurative — they have no depictions of animals, including humans. This latter form of art was perhaps exclusive to Homo sapiens. Instead, the Neanderthal examples consist of hand stencils, made by blowing pigment over the hand, finger flutings — where the fingers were pressed into a soft surface — and geometric markings.

Neanderthals inhabited western Eurasia from about 400,000 years ago until their extinction about 40,000 years ago and have often been caricatured as the archetypal "cavemen".

Questions about their cognitive and behavioral sophistication have never quite gone away, and whether they produced art is at the forefront of this issue.

Despite the fact that we know that Neanderthals were capable of producing jewelry and using colored pigments, there has been much objection to the notion that they explored deep caves and left art on the walls.

But recent work has confirmed beyond doubt that they did. In three Spanish caves — La Pasiega in Cantabria, Maltravieso in Extremadura and Ardales in Malaga, Neanderthals created linear signs, geometric shapes, hand stencils, and handprints using pigments. In La Roche Cotard, a cave in the Loire Valley, France, Neanderthals left a variety of lines and shapes in finger flutings (the lines that fingers leave on a soft surface).

And deep in the Bruniquel cave, southwest France, they broke off stalactites into sections of similar length and constructed a large oval wall of them, setting fires on top of it. This was not a shelter but something odder, and if it was constructed in a modern art gallery we'd no doubt assume it was installation art.

Now that we have well-established examples of Neanderthal art on cave walls in France and Spain, more discoveries are inevitable. However, the job is hard because of difficulties in establishing the age of Paleolithic cave art. In fact, it is often the focus of intense debate among specialists.

Relative dating schemes based on the style and themes of cave art and comparisons of objects recovered from dated archaeological levels have proven useful, but they have their limits.

To produce real ages requires at least one of three conditions. The first is the presence of a charcoal pigment which can be dated using the radiocarbon method. This will establish exactly when the charcoal was created (when its wood died). However, black pigments are often from minerals (manganese) and therefore a large amount of black colored cave art is simply not dateable.

A further problem is that the production of the charcoal may or may not be of the same age as the date that it was used as a pigment. I could pick up some 30,000-year-old charcoal from a cave floor and write "Paul was here" on a cave wall. The radiocarbon date wouldn't reflect when my grafitto was actually made.

A second condition is the presence of calcite flowstones (stalactites and stalagmites) that have formed over the art. If they demonstrably grew on top of a piece of art, then they must be younger than it. A dating method based on the decay of uranium into an isotope — a particular form — of the element thorium can be used to establish exactly when flowstones formed, producing a minimum age for the art underneath.

I was part of a team who used this method to date flowstones overlying red pigment art in the three Spanish caves mentioned earlier, demonstrating that hand stencils, dots and color washes must have been created over 64,000 years ago. This is a minimum age: the actual age of the images could be much older.

But even at its youngest range, the images predate the earliest arrival of modern humans (Homo sapiens) in Iberia by at least 22,000 years. As Middle Paleolithic archaeology — the calling cards of the Neanderthals — is common in all three caves, the simplest interpretation that fits the dating is that the authors of the images were Neanderthals.

Objections to our results ignored supporting information we'd published. Did the dated samples really overlie the art? They did. Can we trust the technique? We have for half a century.

The third condition has just provided further evidence of Neanderthal artistic activity. Meandering lines left by tracing fingers along the soft muds of the walls of the Roche Cotard cave reveal another form of interacting with this mysterious subterranean realm. These markings include wavy, parallel and curved lines in organized arrangements that show they were made deliberately.

The dating of sediments which formed over its entrance show that it was completely sealed no later than 54,000 years ago — probably earlier. As with our Spanish examples, this was long before Homo sapiens arrived in the region and the cave contains only tools made by Neanderthals. It adds another art form to the Neanderthal repertoire.

Even ardent sceptics must agree that this data unambiguously reveal artistic activities in deep caves which can only have been made by Neanderthals.

The art could represent Neanderthal individuals becoming more aware of their own agency in the world. It might constitute the first evidence of engagement with an imaginary realm. The coming years will no doubt reveal even more subjects for debate.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Neanderthals crafted red and yellow "crayons" tens of thousands of years ago, using different techniques to sharpen the instruments' edges into a perfect point, a new study finds.

These Neanderthals, who lived in what is now Crimea, sculpted their crayons out of ocher (also spelled ochre), an iron-containing mineral that can be used as pigment. In the new study, the researchers identified three ocher crayons dating up to 100,000 years ago that appeared to have had "curated use," including one with a sharpened tip.

The finding adds evidence to the debate as to whether Neanderthals were capable of creating art that was symbolic. In this case, although the authors did not discover any actual markings, they suggested that if the Neanderthals had used the ocher for other tasks, such as tanning hides, they would not have required the pointed tip.

The discovery of the crayon with evidence of repeated sharpening suggests that Neanderthals in Crimea sometimes used ocher for socially and culturally meaningful tasks, such as drawing body markings, according to research published Wednesday (Oct. 29) in the journal Science Advances.

Finding a fragment where the tip was clearly resharpened was exciting, said study first author Francesco d'Errico, a professor of archaeology at the University of Bergen in Norway, as it shows the crayon was crafted and maintained for drawing fine lines. "This is really something very special," he said.

However, not everyone agrees with the researchers' interpretations, telling Live Science that there is no direct evidence that these ocher crayons were used to draw cultural or social artwork.

This conclusion would hint at Neanderthals possessing the brain power to create social signifiers and to transform their bodies into cultural objects like our own species, Homo sapiens, does, d'Errico told Live Science.

Prehistoric pigments

Prehistoric humans and their relatives have been playing with pigments for hundreds of thousands of years. So far, almost 40 sites across Europe show evidence of Neanderthals using black, red, yellow or white pigments, but not all uses were for social or cultural purposes.

For example, Neanderthals living in Iberia around 50,000 years ago used red and yellow pigments to paint shells, suggesting symbolic use, while Neanderthals living in what is now the Netherlands were using black minerals 200,000 to 250,000 years ago without evidence of symbolic meaning.

However, there is less clear evidence of Neanderthals using ocher in Eastern Europe and western Asia, and the cultural variants found in those regions have received less attention, the authors wrote in the study.

To determine whether the previously unearthed ocher found at Crimean Neanderthal sites could have been used to create cultural meaning, the researchers focused on 16 ocher fragments from three Crimean rock shelters and one northeastern Ukrainian open air site dated from around 100,000 to 33,000 years ago.

The team closely inspected the ocher fragments' shape and markings to see how they were crafted and used, and examined the elemental makeup of each fragment to determine where it originated.

D'Errico and his team found three fragments, all from Crimea, that they say were likely used for culturally meaningful purposes rather than simply for practical uses, such as tanning hides or repelling insects.

The first was a tool that had been repeatedly scraped and ground to sharpen its point after it became too blunt. This indicates that the ocher was used like a colored pencil to draw thin lines on surfaces such as skin or stones, the researchers suggested. Another fragment appeared to be part of a broken crayon, while a third piece had lines purposefully engraved into its base.

The ocher was sourced from the local outcrop, as well as other currently unknown locations, the team found. D'Errico said that tracing where Neanderthals obtained their coloring materials provides a window into the choices these individuals made and how they perceived differences in color and quality. However, the current sample of crayons is too small to reach any firm conclusions on these individuals' decision making, he added.

A few disagreements

Rebecca Wragg Sykes, an archaeologist at the University of Cambridge and author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury Sigma, 2020) who was not involved in the study, is not convinced by the authors' conclusions.

"The researchers' argument that there is direct evidence for symbolic use here is not necessarily the only interpretation," she told Live Science in an email.

For example, she said that the etchings on the side of one of the fragments do not necessarily mean it was culturally meaningful to the users. "The markings can be understood as a particular powder production method, without implying there was a particular symbolic meaning to them (e.g. as a recurring 'motif' or pattern)," she suggested.

But while the markings themselves may not have symbolic meaning, Neanderthals may have still used colored powders to that end, Wragg Sykes noted.

"The fact I do not think there is strong evidence here for intentional engraved motifs doesn't mean that there was no aesthetic, socially meaningful element in why Neanderthals were making and using coloured powder," she added.

April Nowell, a Paleolithic anthropologist at the University of Victoria in British Columbia who was not involved in the research, argues that there should be less focus on the distinction between symbolic and practical ocher use. Once Neanderthals started to use ocher for practical purposes, such as insect repellent, they likely also developed it for body painting and clothing designs to differentiate individuals or groups, as in nonindustrialized societies today, she told Live Science in an email.

Neanderthal quiz: How much do you know about our closest relatives?

A fatal genetic incompatibility between Neanderthals and modern humans may have hastened the extinction of our ancient cousins, new research suggests.

Researchers found that different versions of a gene tied to red blood cell function may have caused Neanderthal-human hybrid women to miscarry their fetuses.

When Neanderthals and early modern humans met in Eurasia around 45,000 years ago, "they exchanged genes — and may also have passed on hidden reproductive risks that shaped the fate of both lineages," Patrick Eppenberger, co-head of the Evolutionary Pathophysiology and Mummy Studies Group at the Institute of Evolutionary Medicine in Zurich, and colleagues wrote in a study posted to the preprint database bioRxiv Sept. 29. (It has not been peer-reviewed yet.)

The researchers focused on the PIEZO1 gene, which affects red blood cells and is found in both modern humans (Homo sapiens) and Neanderthals. They discovered that the PIEZO1 gene differed between Neanderthals and modern humans.

The Neanderthal variant, which is similar to the variant found in other great apes, allowed the hemoglobin in red blood cells to cling more tightly to oxygen molecules, while the novel H. sapiens variant allowed oxygen to be passed more efficiently into surrounding tissue. Neanderthals may have maintained the original variant because it was beneficial for surviving extreme cold and periods of starvation, the researchers suggested.

But when maternal blood has abnormally high amounts of oxygen bound to hemoglobin, that means low levels of oxygen are passed on to a fetus through the placenta. This can cause hypoxia (oxygen deficiency) or restricted growth of the fetus or miscarriage.

But because of the way the PIEZO1 gene variants are inherited, the incompatibility would arise only when a hybrid Neanderthal-human mother mated with a modern-human father or with a hybrid Neanderthal-human father.

"Many of their offspring would fail to survive," the researchers wrote. This, in turn, would mean Neanderthal women would pass on less of their mitochondrial DNA, which is carried in the egg and passes from mother to child, the authors wrote in the study. Over the course of several generations of mating between Neanderthals and humans, this may have significantly compromised hybrid Neanderthals' ability to have kids, the researchers noted.

"The PIEZO1 incompatibility may have accelerated the demise of the Neanderthals by gradually eroding their reproductive capacity whenever the two groups interacted," they wrote.

April Nowell, a Paleolithic archaeologist at the University of Victoria who was not involved in the study, told Live Science in an email that the study adds a much-needed piece of the puzzle to the question of Neanderthal extinction — namely, maternal-fetal incompatibility in oxygen transfer during pregnancy.

"It's super interesting that an allele [gene variant] that may have saved Neanderthals in the past was their ultimate undoing when they began to interbreed with modern humans," Nowell said.

John Hawks, a biological anthropologist at the University of Wisconsin who was not involved in the study, told Live Science in an email that the maternal-fetal incompatibility of PIEZO1 was intriguing and analogous to other genetic blood conditions, such as Rh factor incompatibility in modern humans.

"This is one of many potential cases where the gene variant coming from an archaic population had some bad effects, causing it to decline in frequency over time in modern people," Hawks said.

But PIEZO1 is not the final answer to the question of Neanderthal extinction.

"There are no single-gene explanations for what was a long and complicated interaction across many archaic human groups, as modern humans entered the places where they lived and interacted with them," Hawks said.

Eppenberger and colleagues emphasized in their study that the effect of interbreeding between Neanderthals and modern humans was likely drawn out and subtle — "more akin to rust weakening a structure than a single catastrophic blow" — and that more research along these lines is needed.

"It is worth pondering how many other loci in the genome might have similarly given rise to hybrid incompatibilities," they wrote.

Neanderthals, our extinct cousins, are often portrayed as eating nothing but meat — no fruit, no grains, no greens. But did Neanderthals really live on meat alone?

While there's plenty of evidence that Neanderthals regularly chowed down on meat, a growing body of research shows our close evolutionary relatives, who went extinct more than 30,000 years ago, also ate other parts of animals besides their meat, such as fat extract from the bone marrow, as well as other foods, including pistachios, lentils and wild peas.

Scientists can estimate the proportions of different foods eaten by ancient humans by analyzing the number of atoms with varying numbers of neutrons in their nuclei, known as isotopes, such as carbon-13 and nitrogen-15. The isotopes humans eat end up preserved in their teeth and bones. These isotopes act as chemical fingerprints, revealing what people and animals ate thousands of years ago.

"Multiple independent isotope studies now converge on the same conclusion," Ludovic Slimak, a paleoanthropologist at the University of Toulouse in France and author of "The Naked Neanderthal" (Penguin Books, 2023) and "The Last Neanderthal: Understanding How Humans Die" (Polity, 2025), told Live Science in an email. "Neanderthals consistently present the isotopic signatures of top-level carnivores."

At the site of Gabasa in Spain, for example, analyses of calcium, strontium and zinc isotopes showed that Neanderthals were hypercarnivores who survived mainly on meat and bone marrow. From what we know, Neanderthals were apex predators, Slimak said, much like wolves and hyenas, which sit at the top of the food chain with no natural predators.

This idea is supported by earlier nitrogen isotope studies, said Hervé Bocherens, head of the biogeology research group at the University of Tübingen in Germany.

Nitrogen comes in two stable forms, or isotopes: nitrogen-14 and the less common nitrogen-15. When animals eat other animals, the heavier nitrogen-15 slowly builds up in their bodies. That means animals that eat meat have more nitrogen-15 than plant eaters.

"In most Neanderthal specimens that have been analyzed, the nitrogen-15 content was higher than those measured in large carnivores, such as cave lions, cave hyenas or wolves," Bocherens told Live Science in an email. "The conclusion was that Neanderthals were 'more carnivore than the carnivores' (hypercarnivores)."

However, he added, this interpretation is too simple. Nitrogen levels can vary depending on which animals Neanderthals ate, not just how much meat they consumed.

"Woolly mammoths consistently exhibit the highest nitrogen-15 levels among herbivores, probably due to the consumption of plants with high nitrogen-15 levels," Bocherens said. The data suggest that Neanderthals were predators that consumed a higher proportion of mammoths than they did of other carnivores in the ecosystem, Bocherens added.

A 2025 study offered a different explanation for Neanderthals' unusually high nitrogen-15 levels: They may have eaten maggots, either by accident, in the process of eating rotting meat, or on purpose.

"Both rotting meat and especially maggots feasting on the rotting meat have high nitrogen levels and any Neandertal eating those foods regularly would have an isotopic signature that is off the charts," April Nowell, a Paleolithic archaeologist and professor of anthropology at the University of Victoria in British Columbia, told Live Science in an email.

But could Neanderthals survive on a solely meat-based diet?

"They could not if they had a similar physiology as modern humans, which is likely," Bocherens said. "There is a need for dietary sources of energy." Eating too much protein without enough fat and carbohydrates, which supply most of our energy, can lead to a fatal condition known as protein poisoning or "rabbit starvation."

Their solution, scientists think, was fat. At one 125,000-year-old German site, researchers found evidence that Neanderthals systematically broke animal bones to extract fat from bone marrow. Animal brains were another probable source of fat, Bocherens said.

When whole carcasses are consumed, including marrow and fat reserves, an animal-based diet is perfectly viable, Slimak said.

Neanderthals ate more than meat and fat

Neanderthals may have found creative ways to balance their nutrition. They might have eaten the stomach contents of their plant-eating prey, Chris Stringer, a research leader in human origins at the Natural History Museum in London, told Live Science in an email.

Scientists agree that Neanderthals also ate plants when they were available. "There is extensive evidence for plant eating by Neanderthals," Nowell said. That evidence includes actual plant remains discovered in caves, microscopic traces left on stone tools, and even plant residues preserved in dental plaque and fossilized feces.

Food remains found in modern-day Israel suggest Neanderthals ate legumes, acorns and pistachios, Nowell said. In Greece and Iraq, plant remains suggest they soaked, pounded and ground lentils, nuts and grasses — a form of food preparation that may have helped remove bitter flavors. In Gibraltar, researchers found the charred remains of edible plants like wild olives and stone pine nuts. In Italy, starch grains found on stone tools hint that Neanderthals were even making a kind of flour.

At El Sidrón Cave in Spain, chemical analyses of dental plaque revealed that Neanderthals ate plants like yarrow and chamomile, likely for medicinal purposes. And, at an open-air archaeological site called El Salt in Alicante, Spain, researchers found significant levels of plant sterols (fats in plants that are similar to cholesterol) in fossilized Neanderthal feces.

In warmer regions, Neanderthals likely gathered a wider range of plant foods, including seeds, starchy root vegetables like tubers, and even dates in the warmest regions, said Robert Power, a research fellow in the School of Archaeology at University College Dublin.

Although Neanderthals were skilled hunters who relied heavily on animal foods, "they varied their diets depending on where and when they lived, adapting to local foods and changing with the seasons," Nowell said.

Neanderthal quiz: How much do you know about our closest relatives?

Humans and our ancestors have been exposed to lead for up to 2 million years, researchers have discovered — overturning the belief that lead poisoning is a relatively modern phenomenon.

What's more, widespread exposure to the toxic metal may have affected the evolution of our species' communication abilities. This would have given Homo sapiens a key advantage over our cousins, the Neanderthals, who were more susceptible to lead's toxic effects, the study suggests.

"Evolution often advances through adversity. Stressors like drought, food/water scarcity, or toxins don’t just threaten survival; they can also drive the selection of traits that make species more adaptable," said study co-author Renaud Joannes-Boyau, professor and head of the Geoarchaeology and Archaeometry Research Group (GARG) at Southern Cross University in Australia. "Lead exposure may be one such hidden force in our evolutionary history," he told Live Science in an email.

However, experts noted the study has limitations, as it estimates lead exposure by measuring lead levels in the teeth of many human and related species.

"It is not obvious whether the amounts of lead detected in the ancient teeth actually were enough to have an impact on health," said John Hawks, an anthropologist at the University of Wisconsin–Madison who was not involved in the study. "Measurements of chemicals in tooth enamel have become incredibly sensitive. It may be that they are detecting such small levels that made no difference," he told Live Science in an email.

Lead is toxic, and high levels of the metal in the body can cause multiple health issues, particularly in children, according to the Cleveland Clinic. It can damage the nervous system, particularly the brain, and other organs and cause severe learning and behavioral problems.

Nowadays, most lead poisoning is the result of human activities and products, such as paint, mining and smelting, according to the Environmental Protection Agency.

But lead also occurs naturally and can be "found throughout Earth's crust, practically in all rocks, soils, sediments, and waterways at various concentrations," the researchers wrote in the study, published Oct. 15 in the journal Science Advances.

"Animals, including humans, can be exposed to substantial levels of lead by drinking contaminated water, ingesting contaminated food, or inhaling polluted air (e.g., smoke from fire and dust storms)," the team added.

Contaminated teeth

In the new study, researchers looked at 51 fossilized teeth dating to between 1.8 million and 100,000 years ago from a variety of species, including Homo sapiens and our closest relatives, Neanderthals, as well as relatives such as Australopithecus africanus and Paranthropus robustus, and the extinct ape Gigantopithecus blacki.

"Teeth form incrementally during childhood, so they preserve a detailed record of early-life exposure, the period when the brain is most vulnerable," Joannes-Boyau said.

The analysis revealed that 73% of the samples showed "clear signals of episodic lead exposure," according to the study. This shows that lead exposure is not a modern phenomenon but has instead impacted human ancestors and relatives for millions of years.

Exposure levels varied, with some lower than modern industrial levels and some higher, but were generally enough to cause impacts in a young, developing brain, Joannes-Boyau noted.

Growing minibrains

To investigate how lead exposure may have shaped the development of Homo sapiens, the researchers created two different versions of brain "organoids" — miniature, simplified models of full-size human brains.

Each organoid version featured different variants of the gene NOVA1. Modern humans have a unique version of this gene that's important for brain development and has also been linked to language skills. Neanderthals and other human relatives have a slightly different version of this gene.

When exposed to lead, the organoid with the modern NOVA1 gene showed greater resistance to the toxic metal than the organoid with the archaic variant. In particular, the Homo sapiens NOVA1 version seemed to help maintain the activity of a gene called FOXP2, which plays a crucial role in the development of human speech and language.

"When the brain is exposed to stressors like lead, the modern NOVA1 variant helps maintain stable FOXP2 function, protecting pathways linked to speech, communication, and cognition," Joannes-Boyau said.

In contrast, in the brain organoid with the archaic variant of NOVA1, FOXP2 expression was altered when exposed to lead.

Study co-author Alysson Muotri, director of the University of California San Diego Sanford Stem Cell Education and Integrated Space Stem Cell Orbital Research Center, noted that this could have given humans an evolutionary advantage.

"Most likely, the modern variant NOVA1 emerged after lead exposure, but was rapidly selected as it gave us an advantage over other hominids," such as Neanderthals, he told Live Science in an email. "This is another example of evolution in action."

But the data on the NOVA1 gene is open to interpretation, Debbie Guatelli-Steinberg, professor in the Department of Anthropology at The Ohio State University, told Live Science in an email.

"The authors argue that the human NOVA1 variant gave humans a competitive advantage over other hominins, including Neanderthals," Guatelli-Steinberg said. "This idea is speculative."

Hawks said the study raises questions about how these ancient human ancestors and relatives were exposed to lead. "Did they take in lead when they used sparkly minerals as pigments?" Hawks said." Did they absorb it in pollutants from burning? Or from the plant foods they ate? These are open questions. I'd love to know the answers."

Neanderthal quiz: How much do you know about our closest relatives?

When scientists sequenced the Neanderthal genome in 2010, they learned that Neanderthals interbred with human ancestors before mysteriously going extinct. As a result, many people alive today share up to 4% of their DNA with Neanderthals.

This genetic breakthrough yielded powerful new information about the evolutionary history of Neanderthals and Homo sapiens, but it also raised a new question: Could we bring back Neanderthals?

George Church, a Harvard University professor of genetics, answered this question in the affirmative in an interview with Der Spiegel in 2013. Church said that, by chopping the Neanderthal genome up into thousands of chunks and reassembling them in a human stem cell, this "would enable you to finally create a Neanderthal clone," which would require an "extremely adventurous female human" to serve as a surrogate.

In 2025, the company that Church co-founded, Colossal Biosciences, made news for "de-extincting" the dire wolf through cloning and gene editing, creating genetically-engineered "woolly mice", and announcing plans to de-extinct the dodo. Their eventual goal is to de-extinct woolly mammoths.

But although Church was confident a decade ago that Neanderthal resurrection was a near-term possibility, other experts told Live Science that doing so is currently an insurmountably difficult task. Even if we could bring them back, there are many reasons we shouldn't, they argue.

"That is one of the most unethical things I can possibly think of to attempt — full stop," Jennifer Raff, a biological anthropologist at the University of Kansas, told Live Science of the idea of bringing them back.

Can we resurrect a Neanderthal?

Resurrecting a Neanderthal is not technologically simple. "You can't just put a Neanderthal genome in a human egg," Raff said. "It just wouldn't work."

One issue with this process is potential immune system incompatibility, which is often what dooms cross-species pregnancies, as the host uterus rejects the fetus. (It's still debated whether modern humans and Neanderthals can be called separate species.)

Although humans and Neanderthals did successfully interbreed in the past, today there is at most 4% Neanderthal DNA remaining in some human groups. "That other DNA might not have been beneficial and so it was slowly purged out of the genome," Raff said.

Additionally, experts have discovered that humans' Y chromosomes lack Neanderthal DNA, which may point to a fundamental immune system incompatibility between male Neanderthal fetuses and the female Homo sapiens carrying them, even in the past. And a genetic variant in red blood cells in Neanderthal-human hybrid mothers might have resulted in high rates of miscarriage, according to other research.

Reintroducing Neanderthal genes that were removed by natural selection over thousands of years into a modern human egg would likely have many unintended consequences, Raff said.

Another route would be cloning, but in order to clone one of our extinct cousins, "we would need a live Neanderthal cell," Hank Greely, director of the Center for Law and the Biosciences at Stanford University, told Live Science, which we obviously don't have because Neanderthals died out more than 30,000 years ago.

With today's CRISPR technology — a form of genome editing — it is possible to modify a human cell's genome to make it more similar to a Neanderthal's. That's what Colossal did when it modified a handful of genes in gray wolves to make them look more like dire wolves. But those weren't actually dire wolves, just like a Homo sapiens with a handful of Neanderthal genes wouldn't be a Neanderthal.

What's more, CRISPR isn't error proof, and it's difficult to incorporate many genetic changes at once.

"You might be able to make 20 to 50 changes now," Greely said, but "at some point, you'll be able to change the entire thing."

While CRISPR technology can be used to cut and modify DNA sequences, a new technique known as base editing, in which scientists change individual letters in DNA's code, may make it easier and faster to precisely edit genomes in the future.

"I think it's likely that, if you really wanted to do it, within 20 years or so, you could probably have a baby with a wholly Neanderthal genome born alive," Greely said. "But I don't think we will do it, even if it is plausible, for both ethical and legal reasons."

Is de-extincting a Neanderthal ethical?

De-extincting Neanderthals is ethically repugnant, experts told Live Science. "It's morally abhorrent to even conceive of trying to create another kind of human based on DNA using uncertain technologies to which they could not consent," Raff said.

But human babies come into the world every day without consenting to being born, Greely said. To him, ensuring the safety of the process and the outcome is the more important ethical issue at hand.

Patients undergoing in vitro fertilization can spare their children certain inherited diseases by selecting embryos without those gene mutations, or by mitochondrial donation, where IVF doctors transfer healthy mitochondria into an embryo to lower the risk of an inherited disease. Editing the genomes of human embryos, however, remains controversial, unproven and risky.

"We don't have experience in editing human embryos to show it's safe," Greely said, which means there is currently "no evidence that transforming them into Neanderthal embryos would be safe."

Even if the Neanderthal embryos could develop into an otherwise healthy Neanderthal, the life they would face once in our world would be unbearably bleak.

Being the only Neanderthal raised in a 21st-century world of humans would likely be lonely and isolating, possibly like the lives of the last Neanderthals in Europe. "They wouldn't have prior generations or peers to learn from," Raff said.

And that's the best-case scenario. The darker possibility is that we would keep any de-extincted Neanderthals in zoos like animals, Raff said, which is abhorrent because "Neanderthals are human — they're just a different kind of human."

Humans don't have a good track record over the centuries of treating other people well, Greely said, so "I have no confidence that we wouldn't be nasty to Neanderthals."

What could we learn from a resurrected Neanderthal?

It's also unclear what kind of information scientists would learn given the fact that the world has changed considerably in the 30,000 years since Neanderthals went extinct.

"A Neanderthal being reconstructed in this way wouldn't be living in the past — they would be living in the present and in an environment that's neither appropriate nor safe for them," Raff said. And since we don't know anything about how Neanderthals' genes interacted with their environment, we would have no idea how physically similar the reconstructed Neanderthal was to past Neanderthals.

"It would fail to answer virtually all of the interesting things that we would want to know about Neanderthals," Rebecca Wragg Sykes, an archaeologist and author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury, 2020), told Live Science.

For example, many researchers are interested in understanding how sophisticated Neanderthal spoken language was. A combination of anatomical studies, genetic information and advanced tool technology suggests they communicated with one another, but possibly without metaphors or abstract words.

Still, even if scientists could bring back a healthy Neanderthal and tried to teach him or her a modern human language, that wouldn't provide much insight into the language they actually used, Wragg Sykes said, just like reconstructing an ancient musical instrument wouldn't tell you what songs people played on it.

"Neanderthals were their own enormous range of different populations with cultural variations, culinary and very likely linguistic diversity," Wragg Sykes said. Since none of the natural context of Neanderthals' development is replicable, "taking a shortcut by cloning or recreating Neanderthals isn't going to get you there."

The same logic holds for other abilities. Teaching one re-created Neanderthal how to read or solve an algebraic equation would only provide as much information about ancient Neanderthals as testing one living human would reveal about the abilities of all humans on the planet.

Is it legal to bring back a Neanderthal?

While resurrecting Neanderthals is wildly unethical, the legality of making one is unclear, according to Greely. While human embryo editing of this nature is illegal in the U.S. and in the E.U., it's unlikely that every country in the world has relevant laws on the books.

"As far as I know, nobody has said it is illegal to make Neanderthals," Greely said. "Theoretically, if a rich guy wanted to set up a lab in the Central African Republic that would be able to do this, it wouldn't be all that hard."

Other scientists are worried about this exact possibility.

In a perspective essay published in the journal PLOS Biology in September, Arthur L. Caplan, a bioethicist at New York University, warned that "the de-extinction of human predecessors could be undertaken at any time by private entities." Caplan exhorted scientists to start a conversation now, when de-extinction of Neanderthals and other human ancestors is only theoretical.

Colossal Biosciences' chief science officer, Beth Shapiro, was asked in 2024 if they will ever have a Neanderthal de-extinction team. Shapiro told Stat News that "Neanderthals were people, and if you're going to work on people, you need to get informed consent. I don't know how you would get informed consent from a Neanderthal that you wanted to bring back to life."

But just because Colossal doesn't seem keen on the idea doesn't mean some other unscrupulous entity wouldn't do it if it were legal.

"Ancient hominid de-extinction should not be left in the hands of private, closely held, for-profit companies," Caplan wrote.

Instead, finding a well-preserved Neanderthal body could be more valuable for understanding the culture and living conditions of our extinct cousins.

Ötzi the Iceman, for instance, was frozen in a glacier in the Alps for 5,300 years. Analyzing his remains has revealed that he sported an animal-skin wardrobe, that he used toxic ferns to wrap his food and that he had dozens of tattoos. And the low-oxygen conditions in a bog in Denmark revealed the exceptionally preserved body of "Tollund Man," who lived 2,400 years ago. That analysis has shown that he had a tapeworm, that he ate porridge for his last meal, and that he was ritually murdered.

Similarly, "if we found a Neanderthal in permafrost or a wetland context like a bog body, that would teach us a huge amount," Wragg Sykes said, "probably more than you would get by having a cloned Neanderthal. That's what I would be more excited about."

Neanderthal quiz: How much do you know about our closest relatives?

When Homo sapiens first emerged in Africa some 300,000 years ago, we did not roam the planet alone.

Our species lived alongside at least six, and possibly more, other human species, from Homo erectus, the first hominin species to venture out of Africa; to Neanderthals and Denisovans, contenders for our closest relatives; all the way to Homo floresiensis — less than 4-foot-tall (1.2 meters) "'hobbits"' who lived on the Indonesian island of Flores.

It's an origin story that Ella Al-Shamahi, a British Arab paleoanthropologist, presenter and explorer, often likens to the Lord of the Rings. Yet, despite its intriguing details, it's also one she says we don't talk about enough.

So Al-Shamahi embarked on a three-year journey across the globe, piecing together our earliest steps and boldest migrations from locations that include Morocco, Namibia, Botswana, Ethiopia, the United Arab Emirates, Sri Lanka, Norway, Romania, France, Canada and Peru. The result is her latest five-part BBC series, "Human," which tells the surprising history of how we came to reshape our planet.

Ahead of the show's Wednesday (Sept. 17) U.S. premiere on PBS, Live Science sat down with Al-Shamahi to discuss it, where we came from, and how H. sapiens became the dominant species on Earth.

Related: Lucy's last day: What the iconic fossil reveals about our ancient ancestor's last hours

Ben Turner: People are going to learn all kinds of things from watching "Human," but most viewers won't come in as experts in the field. I want to know, from your perspective, what did you learn from making it?

Ella Al-Shamahi: There was only one thing that I didn't know going into making the show, and that was the incredible alphabet situation. It's almost at the end of the series that we reveal the real story of how the alphabet was invented. And it turns out it was actually invented by some lowly people, some would call them slaves, in Egypt. They were illiterate, and they were just copying the [hieroglyphs written by] higher-ups on the hierarchy.

But then there was a real thing for me, a thing that I was desperate to do. This has been my subject for 20-odd years, I think it's an absolutely mesmerizing subject area. And I have never understood how people don't know certain things.

Like, for example, I've never understood how people don't know that we were born into a world of many [human] species. There were at least six other species around at the same time [300,000 years ago] as us — I actually think that number is probably much, much higher, and will probably get higher over the coming years — and for me, that becomes like a Lord of the Rings type universe. That captures the imagination, that is a fantastical story.

But add to that, if there were that many species, we think we were probably the underdog of the group. We certainly weren't exceptional, but now we're the only ones left. That then becomes a crazy mystery, and it's actually quite profound. How come we're the ones that did so well? How come we're the ones that won out and won out in such a huge way? And so for me it was this opportunity to scream from the rooftops and to let people know the real story of our origins.

When you're doing these shows, it's hard not to be moved. You turn up to a cave where they're looking at ritual, for example. Or you see an incredible pair of footprints that look like they came from a mother and child walking in the Americas, in New Mexico. I mean, it's just the opportunity of a lifetime to be able to communicate this.

BT: I'm not an expert, but whenever I see stuff like that it surprises me at how emotive it can be. It's not even comparatively that old, but the Cueva de las Manos in Argentina gets me every time I look at it. Is there something — an artifact, a relic, ritual or cave painting — that stands out as a tear-jerker for you?

EAS: There are so many, that's the incredible thing. If I had to pick one, there's a cave called Rhino Cave [in Botswana]. It has an outcrop where the rock itself is shaped like a serpent, it even has a slit for the mouth. And these humans came along and they essentially chipped what looked like scales, like hundreds of these scales, into the rock, to really make it look like a serpent. They made these stone tools, which were beautiful, and then they destroyed them before using them, which you don't tend to do unless you're making an offering.

Caves are a magnificent thing to be in at the best of times. We waited until the evening, and we basically put in something that looks like candle light, so we got the full effect. And it was magnificent. It was really magnificent because we are the only animal that does ritual in that way. You don't see chimpanzees, [one of] our closest living relatives, doing that kind of thing. It's the ability to see beyond what is in front of you, and to imagine a different world. And it was really profound, because so far we think that's the earliest site of ritual that we have evidence for.

And you wondered when you sat there what people were wishing for, what these offerings were about.

BT: You mentioned earlier that modern day humans were one of at least seven known human species at the time of their emergence. And you also said we were underdogs. Is there anything that sets us apart, aside from the ostensible fluke that we're still around?

EAS: I think it's fair to say it's probably a combination of things, but if you put 10 different anthropologists in a room, we would all come up with slightly different answers to that.

I think we [in the show] argue very heavily that it's cooperation. We are an incredibly cooperative species. There's this thing called cumulative culture, which is a theory that I've been trying to get on television for like, seven odd years.

It doesn't particularly sound sexy, if I'm gonna be honest, but it's the idea that every generation builds upon previous generations — their technology and science and art. We basically argue, like a lot of paleoanthropologists, that, as a species, there were a lot of us and we were very cooperative.

Cumulative culture, because of the way our brains were, came into play. And it came into play in a big, big, big way. Suddenly you ended up with technology that was just so much better because we were this highly cooperative species. It's kind of funny to think about it, because at the end of episode one, I basically say: "Look, we're the friendly species," and that really does raise people's eyebrows, because they're like: "We? Homo sapiens? The friendly species?"

I put it to you that cooperation is friendliness. Cooperation is the ability to be friendly and work with the people around you. What other species has built what we've built? Name them. We're clearly highly cooperative.

We also argue that climate came into play, and for various reasons, including the fact that we have a source population in Africa, we were doing better. And our technology was able to adapt better because of the cooperation that we had. But I also think there's just an element of luck.

BT: Us being the "friendly" species contradicts some of the older ideas about what made us survive. It's like the depiction of humans in William Golding's [1955] novel The Inheritors, the idea that we beat these other species through sheer brains, or brawn, or a combination of both. That's what a lot of people still assume.

EAS: Yeah we've got no evidence that we made war with any of these species. Ironically, we do have evidence we made love with them.

There's suggestions that we might have fought, but there's no conclusive evidence. I think what is more likely, and this is my own reading of the data, is that we were formidable competition. In the end, by the time we had become the species we know today, we were formidable.

But honestly, I think it's more subtle than people realize. I think the fact that we're here and they're not is — oh, it was close. There's a mountain in Israel called Mount Carmel, and there's two caves. For about 30,000 years, maybe, give or take, we think that Neanderthals were living there [in one cave]. And in another cave on that same mountain, Homo sapiens were living there.

Which, first of all, amazing. Like how cool is that, on the same mountain? But secondly one of them went locally extinct, and it wasn't the Neanderthals. It took a few more tens of thousands of years for us to get the upper hand. So it was close, at times it was really close.

Related: Did we kill the Neanderthals? New research may finally answer an age-old question.

BT: You mention making love and not war. There's another old idea, famously summed up in Rudolph Zallinger's March of Progress illustration, that we didn't really interbreed that much with other Homo species and instead cut a fairly linear evolutionary path, from chimp-like apes through Homo erectus to modern-day humans. That's got to be pretty misleading, right?

EAS: Yeah, it's funny, I speak about that image a lot in my talks. There are a few issues with the image, but the primary one is that it gives the impression that evolution is linear: one species leads to another species, and that first species all becomes extinct; and then that second species leads to the third species, and then that second species all becomes extinct. And we know that's just not the case.

It's certainly not the case with our species and our relatives. We were splitting at various points on this family tree, with other species sharing an ancestor with them. We call the Neanderthals our sister species, which effectively means they were our closest relatives, like a cousin. But when we met them again, we would occasionally have sex with them. Evolution is not that straight line, it's this complicated bush, and it makes it so much more interesting. I just think it's fantastic. What would it have been like to live in that world?

BT: This is a slightly silly question, but I have to ask it. Do you have a particular Homo species you'd have been most interested to meet?

EAS: It used to be Neanderthals, they're my subject area, but with time it became Homo floresiensis or "hobbits." They're basically these tiny, miniature humans that lived on the island of Flores [in Indonesia].

They were recently described as "humans the size of penguins" and on the island there were giant, flesh-eating, carnivorous marabou storks that were taller than me, over 6 foot [1.8 meters]. There were giant rats, massive komodo dragons, but also miniature elephants called stegodons that were the size of cows. And you think, well that's interesting, wouldn't mind meeting that lot, finding out what's going on there.

Then there are Denisovans. They've been this mystery that's been unfolding since 2010 [following their initial discovery] you know, who were the Denisovans? Turns out we now know who the Denisovans are, but it's still quite a mystery.

But, gun to my head, I would probably go with the hobbits. That's probably not an answer anyone's expecting.

BT: I mean I get it, there's something really Swiftian [the Anglo-Irish writer of Gulliver's Travels] about them. Living on this fantasy island of disproportioned creatures.

EAS: Yeah! There was actually a second hobbit-like species living on the islands of the Philippines.

BT: So what's the relevance of all this to the present? What can studying our past teach us about ourselves today? If anything?

EAS: Well, I would say that we're forged in the Paleolithic, and we are a byproduct of our DNA. In fact, that DNA has actually moved on very, very, very little in the intervening years.

You can see the origins of so much when you study our history. But it's more than that, I think it gives us the context for so many things that are right, and wrong, about ourselves. So there's ritual and the way we see the world, the fact that we take risks the way we do, our imagination and creativity that no other species has, our cooperation, our love of dogs, and how much we need other humans — we don't do well as loners.

I often describe cities and agriculture as the biggest trade-offs we've ever made. Because, on the one hand, more of us are able to survive. But on the other hand, we're surviving in a way that is no longer the world that our DNA was built for. It's suboptimal, we weren't designed to be staying in one place, our biology isn't really about that. It gives us a lot of context for who we are and why things don't always fit.

What was really interesting about this series is that, when we started making it, one of the things that I kept getting told was we need to be explaining to the public why human evolution is so fascinating. I had all the usual answers, we've sequenced the Neanderthal genome, and we've now got ancient DNA and our family tree's bigger and all this stuff. But there was another answer that I had, which was that nobody ever asks us to justify why space is fascinating or relevant. You often hear from astronauts that when they look back at our tiny, little blue dot, that it gives them context and it gives them perspective.

When I sit on top of deep-time archeological sites and know the stories of the people that are underneath me — fascinating stories about people that seemed really resilient who suddenly disappeared; people that were a Neanderthal group suddenly overtaken by a Homo sapiens group; sometimes scandalous stories, cannibalism, inbreeding, etcetera — it gives you perspective. I often think that space is magnificent, but time is who we are.

BT: It's interesting that, despite how much we know, so much of the story remains undiscovered. We emerged from Africa, but DNA degrades quite easily in the warmer conditions there and so the genomic maps are all from the Eurasian hinterlands. Are there any scientific questions you're excited about that could fill these gaps in our knowledge?

EAS: Oh, so many. There's a lot of talk about Denisovans and their relationship to us in the family tree. Traditionally, we saw the Neanderthals as our sister group closest to us, but there is a suggestion that maybe it's the Denisovans which then makes us more centered, but it's just too early [to know].

I think it would be very helpful to know just how many other human species [there are]. It would also be really quite helpful to understand, beyond just theories, what it was that eventually made us "Homo sapiens 2.0." There's a suggestion that something happened in our brains. It would be really fascinating to know for sure if that was the case.

But for some of these questions, the answers to them may not come for a very, very long time. I think just knowing the way science is, they'll come. We just don't know how long we'll be waiting for them.

BT: You also did a TED Talk on the "The fascinating (and dangerous) places scientists aren't exploring." So what about the non-scientific barriers? They're all places that were cradles of our species. What could we be missing out on due to scientists not having easy access to vast regions of the Middle East, like Yemen and the Sinai, and Asia, North and Central Africa?

EAS: It's like low-hanging fruit. There are incredible archeological discoveries being made in New Mexico, for example. You know how many archeologists there are in New Mexico? A lot. There are incredible archeological discoveries being made in France. Again, lots of archeologists working in France.

So then imagine places we would call "red zones" or places that are politically unstable that barely have any archaeologists working in them. I work in Somaliland, if you look at the countries that neighbor it, they're all paleo dreams, places with significant human fossils. Are we to believe that our ancestors didn't enter Somaliland [from these places]? Of course they did. We just have no evidence because nobody's looking, and we're all poorer for it.

But I also think there's a bigger issue, which is that I think science is best when everybody is at the table. It's a tragedy that so many people in those places don't have access to becoming these kinds of scientists.

BT: To round this off, I know we've already touched on some of the unanswered questions, but you said many of them could take some time. Are there any you see us answering sooner, in the near future?

EAS: I think we'll be adding more species to the family tree, and also understanding those relationships a little better. I also suspect at some point we'll get closer to understanding what's going on with FOXP2.

FOXP2 is described in some circles as "the language gene" but it's clearly so much more than that. It looks like it's different between us and the Neanderthals. The question is what is it about? I think it's something about the way our brains process [information].

Editor's note: This interview has been condensed and edited for clarity. Human will premiere in the U.S. on PBS on Nova on Sept. 17.

Tiny stone artifacts discovered in Uzbekistan may be the oldest known arrowheads, a new study suggests.

It remains unclear whether these stone tools were created by modern humans, Neanderthals or some other group.

Archaeologists found the tools at the site of Obi-Rakhmat in northeastern Uzbekistan. Previous excavations uncovered a variety of stone tools at the site, such as thin and wide blades, and smaller "bladelets." But numerous small, triangular points — called "microliths" — were overlooked in prior work because they were broken.

Now, in a study published Aug. 11 in the journal PLOS One, the researchers argue that these "micropoints" are too narrow to have fit onto anything other than arrow-like shafts. The stones also display the kind of damage that would be expected from used arrowheads, study co-author Hugues Plisson, an associate scientist at the University of Bordeaux in France, told Live Science.

These micropoints, which are about 80,000 years old, may therefore be the oldest arrowheads in the world — around 6,000 years older than 74,000-year-old artifacts unearthed in Ethiopia, the researchers say.

The scientists expect their work to raise doubts.

"The bows themselves and the arrow shafts have not been preserved, so some skepticism from colleagues is expected," study co-author Andrey Krivoshapkin, director of the Siberian branch of the Russian Academy of Sciences' Institute of Archaeology and Ethnography, told Live Science.

Related: 1.5 million-year-old stone tools from mystery human relative discovered in Indonesia — they reached the region before our species even existed

Still, these findings suggest "complicated early weapons and hunting technologies were more geographically widespread at an earlier date than previously supposed," Christian Tryon, a Paleolithic archaeologist at the University of Connecticut who did not take part in this research, told Live Science. "As usual, we consistently underestimate the abilities of our ancestors."

It remains uncertain which group created the stone artifacts found at Obi-Rakhmat.

While excavating at the site in 2003, archaeologists discovered six teeth and 121 skull fragments from a child between 9 and 12 years old. Although the teeth resembled those of Neanderthals, the skull's features were more ambiguous, raising the question of whether the child was a member of our species, or possibly a hybrid between Homo sapiens and a Neanderthal or Denisovan.

Central Asia was Neanderthal territory when the oldest of these potential arrowheads were made in Obi-Rakhmat, Plisson said. However, there are no known Neanderthal arrowheads, the study noted. The researchers suggested the Obi-Rakhmat artifacts were most likely created by H. sapiens.

"The appearance of the Obi-Rakhmat population in Central Asia coincides with the presumed time of the dispersal of anatomically modern humans in Eurasia," Krivoshapkin said. The researchers told Live Science that these migrants might have originated from the Levant, the eastern Mediterranean region that today includes Israel, the Palestinian territories, Jordan, Lebanon, Syria and some surrounding areas.

When modern humans arrived, the region that included Obi-Rakhmat may have already been inhabited by other groups, such as Neanderthals, the scientists contended, adding that the microlith technology could have helped them obtain food in their new environment.

"Our discovery helps us identify the subsistence characteristics that allowed the Obi-Rakhmat people to successfully compete with groups who had long since adapted to living in the landscapes we are studying," Krivoshapkin said.

The scientists are now attempting to discover when the people of Obi-Rakhmat first arrived in Central Asia. They hope to find archaeological and genetic links between them and groups in the Levant. They also plan to investigate other, potentially older archaeological sites in the region, which may reveal arrowheads even older than 80,000 years.

"These innovations could have appeared much earlier and persisted over a long period," Krivoshapkin said.

"It would be wonderful to find the sites where the hunting actually took place," Tryon said. "But these sites are difficult to find on the landscape."

Human evolution quiz: What do you know about Homo sapiens?

A mysterious skull with a stalagmite growing out of its head is about 300,000 years old and neither human nor Neanderthal, a new study finds.

The skull was reportedly discovered attached to the wall of Petralona Cave in northern Greece in 1960. Researchers have since argued about its position on the human family tree and had trouble figuring out its age — until now.

In the new study, published online Aug. 14 in the Journal of Human Evolution, researchers dated calcite (a mineral form of calcium carbonate often found in caves) protruding out of the skull to find that it was at least 277,000 years old. They don't know precisely how long the skull was in the cave before it began acquiring calcite, but the new estimate helps narrow down previous attempts to date the skull, which have ranged from 170,000 to 700,000 years old.

The findings support previous suggestions that the Petralona individual lived in Pleistocene-era Europe alongside Neanderthals, but was part of a different human group, broadly called Homo heidelbergensis.

The Petralona fossil is distinct from H. sapiens and Neanderthals, study co-author Chris Stringer, a paleoanthropologist at the Natural History Museum in London, told Live Science, "and the new age estimate supports the persistence and coexistence of this population alongside the evolving Neanderthal lineage in the later Middle Pleistocene of Europe".

Related: 'It makes no sense to say there was only one origin of Homo sapiens': How the evolutionary record of Asia is complicating what we know about our species

The Petralona skull, sometimes called the "Petralona Man," was almost certainly male based on the fossil's size and robustness, according to Stringer. He also said that the skull's teeth had moderate wear, so it likely belonged to a young adult.

While records of the skull's discovery are poor, Stringer noted that there's evidence to support the idea that it was stuck to the wall by calcite encrustations — the same kind that were protruding out of the skull.

To estimate the age of the calcite, researchers used a method called uranium-series dating. Calcite contains a small amount of uranium, which decays into another radioactive element called thorium over a fixed period. This fixed rate of decay means that researchers can calculate ages based on the calcite’s ratio of uranium to thorium. The skull calcite dates back to around 286,000 years ago, with a high degree of confidence that it's at least 277,000 years old.

The dating research also suggested that calcite grew quite rapidly in the cave. Stringer noted that it likely didn't take long for the skull to acquire its first layer of calcite, which would mean the skull is around 300,000 years old. However, the skull could be older than 300,000 years old if the calcite took longer to form.

The estimate of 300,000 years old fits with Stringer and colleagues' analysis of a similar fossil from Zambia in Africa known as the Kabwe skull. Their 2019 study dated the Kabwe skull, which is often assigned to H. heidelbergensis, at 299,000 years old.

"That fossil is closely comparable to the Petralona one, and I would classify them both as Homo heidelbergensis," Stringer said.

A protein that helps synthesize DNA is different in modern humans than it is in Neanderthals and Denisovans — our closest extinct relatives — and new experiments in mice genetically modified to express the modern human version hint that this may have made us behave differently.

That discovery, in turn, could shed light on why Neanderthals and Denisovans vanished, researchers propose in a new study.

But the significance of the findings for humans is still unclear.

"It's too early to translate these findings directly to humans, as the neural circuits of mice are vastly different," study lead author, Xiangchun Ju, a postdoctoral researcher at the Okinawa Institute of Science and Technology in Japan, said in a statement. However, this work hints that the variant seen in modern humans "might have given us some evolutionary advantage in particular tasks relative to ancestral humans," such as competing for scarce resources.

Key protein

Previous research found that modern humans diverged from their closest evolutionary relatives, Neanderthals and Denisovans, about 600,000 years ago. It's not clear why modern humans survived while our closest relatives died off.

To search for potential genetic clues to solve this mystery, the researchers analyzed the enzyme ADSL (adenylosuccinate lyase). This protein helps synthesize purine, one of the fundamental building blocks of DNA and other vital molecules.

Related: A braided stream, not a family tree: How new evidence upends our understanding of how humans evolved

"There are a small number of enzymes that were affected by evolutionary changes in the ancestors of modern humans. ADSL is one of them," study co-author Svante Pääbo, Nobel laureate, leader of the human evolutionary genomics unit at the Okinawa Institute of Science and Technology in Japan, and director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, said in a statement.

ADSL is made up of a chain of 484 amino acids. The version of this enzyme found in virtually all modern humans differs from that seen in both Neanderthals and Denisovans by just one amino acid — the 429th amino acid in ADSL is valine in modern humans but alanine in our extinct relatives.

The scientists noted the ADSL mutation is seen in modern humans and not our closest extinct relatives, and so likely appeared after we separated from the lineage that led to Neanderthals and Denisovans. This led the researchers to investigate the possible behavioral effects of this mutation.

Previous research on lab-grown cells found that the ADSL variant seen in modern humans resulted in a more unstable version of the enzyme that broke down more quickly compared to the one in Neanderthals and Denisovans.

Behavior changes

The new study, published Aug. 4 in the journal PNAS, similarly found that, in mice, the modern variant leads to higher levels of the chemicals that ADSL normally acts on to synthesize purine in several organs, especially the brain. This finding supported the idea that the modern human version of ADSL is less active than the variant seen in Neanderthals and Denisovans.

In experiments where mice learned they could get a drink of water following specific lights or sounds, female mice genetically modified to possess a version of ADSL similar to the kind seen in modern humans were better at getting water than their littermates without this variant were. This might suggest the human-like variant made female mice better at learning to connect the dots between the water and the lights or sounds, or more motivated to seek out the water in some way.

The changes in behavior and ADSL levels seen in female mice with the modern-human variant of the enzyme was not seen in male mice. "It's unclear why only female mice seemed to gain a competitive advantage," study co-author Izumi Fukunaga, a researcher at the Okinawa Institute of Science and Technology, said in a statement. "Behavior is complex."

Statistical tests analyzing Neanderthal; Denisovan; and modern African, European and East Asian DNA found that mutations in the ADSL gene appeared in modern human genomes at higher rates than random variations over time would suggest, making it likely that these mutations provided some evolutionary advantage.

Perhaps running counter to the new findings, prior work found that genetic disorders leading to ADSL deficiency in modern humans can lead to intellectual disability, speech and language impairment, and other problems. This suggests that during evolution, modern humans had to balance the potential benefits of reducing ADSL activity with the problems that could occur from ADSL deficiency, study co-author Shin-Yu Lee, also of the Okinawa Institute of Science and Technology, said in a statement.

Implications unclear

Not everyone thinks the study has direct implications for why modern humans thrived or for why Neanderthals or Denisovans disappeared.

These results in mice "don't say too much about human evolution at this stage," Mark Collard, a paleoanthropologist at Simon Fraser University in Burnaby, British Columbia who did not take part in this research, told Live Science.

However, the strategy of using mice to study the behavioral effects of genetic differences between modern humans and our closest extinct relatives "seems very promising as a way of investigating the evolution of our brain and behavior," Collard said. "I expect we'll see a cascade of studies like this one in the next few years."

Future research can investigate the specific mechanisms by which changes in ADSL activity influence behavior. Scientists can also explore how changes in ADSL activity are associated with other behaviors and how multiple genetic changes might work in concert, the study authors wrote.

The story of our ancient ancestors began in Africa millions of years ago. But there are considerable gaps between the first and current chapters of that tale, and some anthropologists are looking to Asia to fill in missing information about how humans evolved.

"The genus Homo evolved in Africa," Sheela Athreya, a biological anthropologist at Texas A&M University, told Live Science. But as soon as Homo left the continent, "all bets are off because evolution is going to treat every population differently."

One bet Athreya is investigating is the notion that there wasn't a single origin of our species, Homo sapiens. Rather, the ancestors of today's humans living in different geographic regions took different evolutionary paths, before eventually coalescing into the human tribe we know today.

Once humans left Africa, "you have so much complexity that it makes no sense to say there was only one origin of Homo sapiens," Athreya said.

Key to this story is a different understanding of human evolution in Asia — and the possibility that Denisovans, a group of little-understood extinct human ancestors known from just a handful of fossils, were actually the same as a much earlier member of our family tree: Homo erectus, Athreya argues.

Related: Strange, 300,000-year-old jawbone unearthed in China may come from vanished human lineage

Early humans in ancient Asia

There's a big gap in human evolutionary history. We know Homo evolved in Africa and that a human ancestor, Homo erectus, was already in Asia and parts of Europe by about 1.8 million years ago. But what happened in Asia between that point and the time when Homo sapiens arrived around 50,000 years ago? That picture is much less clear.

To help fill it in, Athreya has considered the emergence of our species, Homo sapiens, during the Middle and Late Pleistocene epoch (780,000 to 11,700 years ago). Her "deep-dive" into the human fossil record of Asia has convinced her that there are evolutionary pathways in places like Java, Indonesia, that differ from the Pleistocene patterns seen in Africa and Europe.

H. erectus reached Java at least 1.5 million years ago, and the species likely lasted there until 108,000 years ago. But the lack of more recent H. erectus bones doesn't necessarily mean they went extinct, Athreya wrote in a 2024 study with co-author Yousuke Kaifu, an anthropologist at the University of Tokyo. Instead, these Javanese H. erectus could have persisted until H. sapiens appeared in Sumatra as early as 73,000 years ago and interbred with them.

The fossil record in China is similarly complicated. Around 300,000 years ago, there was a shift in what H. erectus fossils looked like, Athreya said. Skeletons in the Middle Pleistocene in China became more variable in form, and traits that were common in Western Eurasian groups like H. sapiens and Neanderthals, such as smoother bicuspid teeth, began to appear in these fossils.

This means that — instead of completely dying out — H. erectus in China may have made a genetic contribution to populations living today, Athreya said, just as Neanderthals left genetic traces in people with European ancestry and Denisovans contributed DNA to people with Oceania ancestry.

The idea isn't impossible, one expert told Live Science.

Groups of ancient human relatives could have mated anywhere they met up, Adam Van Arsdale, a biological anthropologist at Wellesley College in Massachusetts, told Live Science. No matter where they lived, "I just think humans aren't that different" during the Pleistocene.

What's more, anthropologists are starting to realize that many of these groups that looked very different could still have interbred. Twenty years ago, scientists would have said "there's no possible way" they could have interbred, Van Arsdale said. "And I just don't think we can assume that anymore."

So far, no DNA has been recovered from H. erectus fossils, largely because most of their fossils are too old, so there's no genetic support for this idea. But emerging methods for extracting ancient proteins from fossils may soon make it feasible to identify some H. erectus genes.

Another route to understanding the fate of H. erectus in Asia may be to look more closely at the enigmatic Denisovans.

Since the only known skull of a Denisovan looks similar, in many ways, to that of H. erectus, those two groups may actually be one and the same.

"I don't think that genetics is going to find that Homo erectus was a separate dead-end lineage," Athreya said. "I would expect Denisovans to be Homo erectus."

But until more work is done that combines DNA, artifacts and fossil bones in Southeast Asia, the full picture of human evolution cannot yet come into focus the way it has in places like Europe, Athreya said.

Human evolution quiz: What do you know about Homo sapiens?

Neanderthals that interbred with our ancestors may have passed on DNA that causes some people to develop a potentially fatal condition where the brain bulges out of the skull, a new study finds.

The disorder, known as Chiari malformation type I, affects the lower part of the cerebellum, the part of the brain that helps control motions. In people with this condition, the cerebellum protrudes through the hole at the base of the skull and into the spine. Symptoms may include headaches, neck pain and dizziness, and if too much of the brain bulges out, it can be fatal.

In mild cases, the symptoms may be treated with muscle relaxants, whereas in severe cases, doctors may treat the condition by removing chunks of bone from the braincase or vertebra, Mark Collard, a paleoanthropologist at Simon Fraser University in British Columbia, told Live Science.

Discovered in the 1800s by Austrian pathologist Hans Chiari, the disorder is thought to affect about 1 in 1,000 people. However, recent imaging research suggests it may be significantly more common, potentially occurring in more than 1 in 100 people — it's just that most cases escape notice because they do not manifest major symptoms, Collard said.

Chiari malformation type 1 happens when the occipital bone at the back of a person's skull is not big enough to hold the brain properly, leading the bulging portion to become pinched. However, it remains uncertain what causes the occipital bone to be unusually small.

In a 2013 study, scientists proposed that the condition was the consequence of interbreeding between Neanderthals and modern humans in Eurasia. Previous research found such intermixing led the genomes of all non-Africans to contain 1.5% to 2% Neanderthal DNA.

Related: 'More Neanderthal than human': How your health may depend on DNA from our long-lost ancestors

Modern human skulls are globular, with a rounded back of the skull, whereas Neanderthal skulls were relatively elongated, with a more angular back of the skull. The 2013 study suggested Neanderthal DNA might influence modern human skull development, leading to a mismatch between the size and shape of the brain and the skull — especially the base of the skull.

To explore this idea, the new study examined 3D CT scans of the skulls of 103 living people — 46 with the disorder, and 57 without. The researchers compared these skulls with eight fossil skulls of close relatives of modern humans, including Neanderthals, Homo heidelbergensis, Homo erectus and prehistoric Homo sapiens.

Study lead author Kimberly Plomp, an osteologist at the University of the Philippines Diliman, and her colleagues found that the skulls of modern humans with the disorder were more similar in shape to Neanderthals than people without the malformation. All other fossil skulls were more similar to modern humans without the disorder.

"Our study may mean we are one step closer to obtaining a clear understanding of the causal chain that gives rise to Chiari malformation type 1," said Collard, a co-author on the study. "In medicine, as in other sciences, clarifying causal chains is important. The clearer one can be about the chain of causation resulting in a medical condition, the more likely one is to be able to manage, or even resolve, the condition."

Collard stressed these findings do not definitively prove a link between this disorder and Neanderthal genes. "Scientific research is rarely, if ever, conclusively based on a single study," he noted.

Future work could analyze more skulls, especially fossil ones, Collard said. Researchers can also focus on collecting data from Africa. "What we know about the occurrence of Neanderthal DNA in the living human gene pool suggests that we should expect higher prevalence of Chiari malformation type 1 in Europe and Asia than in Africa," Collard said.

If future research does confirm a link between Neanderthal genes and this disorder, "then it might make sense to add screening for such genes to early childhood health assessments," Collard said. That way, individuals with a higher-than-average risk of developing Chiari malformation type 1 could be identified and then monitored and managed by health professionals.

The scientists detailed their findings June 27 in the journal Evolution, Medicine, and Public Health.

Neanderthal quiz: How much do you know about our closest relatives?

Just before the first COVID lockdown in March 2020, Carlos Neto de Carvalho and his wife, Yilu Zhang, were walking along Monte Clérigo beach in southern Portugal. As the geologist and geographer couple scrambled over rocky outcrops and an old collapsed cliff, they stumbled on a series of ancient Neanderthal footprints.

"It was early in the morning of a sunny day, with perfect light for checking tracks," Neto de Carvalho told Live Science in an email. But when they brought colleagues back to the site to take photos of the tracks, "we were almost trapped by the sudden rise of the tide and needed to swim and climb a 15-meter [49 feet] nearly vertical cliff with all our gear," Neto de Carvalho said.

Their daring adventure paid off. The researchers ultimately discovered five trackways comprising 26 footprints at Monte Clérigo and, in turn, substantially increased experts' understanding of Neanderthals' activities along the Atlantic coast 78,000 years ago.

"The fossil record of hominin footprints, and especially the ones attributed to Neanderthals, is exceedingly rare," Neto de Carvalho and colleagues wrote in a study published July 3 in the journal Scientific Reports, since Neanderthal footprints are nearly identical to humans'.

In this case, the footprints were identified as Neanderthal because modern humans weren't in Europe at that time. Rather, evidence suggests that besides a few earlier failed attempts, Homo sapiens started leaving Africa around 50,000 years ago.

Only six sets of Neanderthal footprints had been discovered previously. Along with the Monte Clérigo tracks, the researchers have reported the new finding of a single footprint from Praia do Telheiro, also in southern Portugal, bringing the total number of Neanderthal trackways discovered in Europe to eight.

At Monte Clérigo, the ancient footprints were made near the shoreline in a coastal dune. Optically stimulated luminescence dating, which measures the last time a mineral was exposed to sunlight, placed the footprints in the range of 83,000 to 73,000 years old.

Related: DNA of 'Thorin,' one of the last Neanderthals, finally sequenced, revealing inbreeding and 50,000 years of genetic isolation

Based on the size and shape of the Monte Clérigo prints, the researchers think an adult Neanderthal male walked up and down the dune, accompanied by a child between 7 and 9 years old and a toddler under 2 years old.

"The fact that in the context of Monte Clérigo infant footprints were found together with those of older individuals suggests that children were present when adults performed day-to-day activities," the researchers wrote.

Because the trackways were heading both toward and away from the shore, these Neanderthals may have been foraging for food, such as shellfish. But another possibility is that the Neanderthals were practicing ambush hunting or stalking prey such as horses, deer or hares, according to the researchers, since some of the Neanderthal footprints were "overprinted" with large mammal tracks.

"At the Monte Clérigo site, the presence of footprints attributed to, at least, one male adult, one child and one toddler, negotiating the steep slope of a dune, allow us to speculate about close proximity to the campsite," the researchers wrote.

But if the Neanderthals had established a camp at Monte Clérigo, no evidence of it remains today.

"The presence of Neanderthals in these environments was intentional even if seasonal," the researchers wrote, "taking benefits from ambush hunting or stalking prey in a rugged dune landscape."

Neanderthal quiz: How much do you know about our closest relatives?

Scientists have uncovered a genetic variant, inherited from Neanderthals, that may limit athletic performance.

The mutation is thought to affect roughly 8% of modern-day Europeans and influences the activity of a key enzyme in the production of energy in skeletal muscle.

In a study published July 10 in the journal Nature Communications, researchers analyzed more than 2,700 individuals, which revealed that those who carried the Neanderthal gene variant were half as likely to become top athletes as those without the variant.

The variant was found in up to 8% of present-day Europeans, 3% of Native Americans and 2% of South Asians, while it was absent in Africans, East Asians and African-Americans. "Since modern humans mixed with Neanderthals around 50,000 years ago, particularly in Europe and Western Asia, non-African populations today carry about 1–2% Neanderthal DNA," Dominik Macak, the study's first author and Doctoral Student at Max-Planck-Institute for Evolutionary Anthropology, told Live Science in an email.

While the Neanderthal variant is not linked with any major health issues, its impact on the body's ability to produce energy during intense exercise could lead to reduced athletic performance in endurance and power sports, the researchers say.

During exercise, cells gain energy by breaking down a molecule called adenosine triphosphate (ATP), often described as our body's "batteries". One way that our body creates ATP, particularly during intense exercise, is by turning two molecules of adenosine diphosphate (ADP) into one molecule of ATP and one of adenosine monophosphate (AMP).

The ATP produced by this reaction is used to power energetic processes in our cells, while the AMP byproduct is removed by an enzyme called AMPD1. It's this enzyme that is impaired in those with the Neanderthal gene variant, the researchers found.

To test the impacts of this gene variant, scientists recreated the Neanderthal version of the AMPD1 enzyme in the lab. They found that it was 25% less active than the enzyme produced in humans with other variants of the gene. Next, they genetically engineered mice to express the altered AMPD1 and found that the enzyme was up to 80% less active than the non-Neanderthal variant.

The researchers then analyzed the prevalence of the gene among elite athletes and non-athletes. They found that 4% to 14% of athletes carried this genetic variant, while 9% to 19% of non-athletes had the variant. Carrying just one copy of the Neanderthal gene (out of the two copies inherited from parents) led to a 50% lower probability of achieving elite athletic status, the data suggested.

Those that carry the Neanderthal gene may struggle with more extreme exercise because the impaired enzyme will allow AMP to build up in their muscles, making it harder for them to produce ATP as fast as their cells need. However, having the Neanderthal gene variant is unlikely to affect most people's daily activities, where energy is obtained by other means. It is only during endurance sports or in exercises that demand muscular power that carriers might be at a slight disadvantage, the researchers said.

But how might this variant have impacted the Neanderthals themselves? "It's very unlikely that this single genetic variant played a role in the extinction of the Neanderthals," Macak said. "We find it in both early and later Neanderthal individuals, suggesting it was stably present over thousands of years. Additionally, some modern humans today carry mutations that disrupt the AMPD1 protein entirely, often without any major health issues. So, while the gene affects muscle metabolism, it likely wasn’t a decisive factor in their ability to survive."

One of the earliest known human burials — that of a young child — could have been a cross between modern humans and Neanderthals, a new study suggests.

Researchers analyzed a skull that was found at a 140,000-year-old burial site and concluded that the child it belonged to had both modern human (Homo sapiens) and Neanderthal characteristics. However, the child's precise ancestry is still uncertain.

The skull was part of a cache of mysterious human remains unearthed almost 100 years ago in Skhul Cave, located on Mount Carmel in Israel. These fossils have been the subject of much scientific debate since their discovery, but were largely considered to be anatomically modern humans.

Skhul Cave is the earliest of all known organized human burial sites, so the identity of the remains buried there is significant. The authors of the study, published in the July-August issue of the journal L'Anthropologie, argued that based on their analysis, the remains can no longer be attributed exclusively to Homo sapiens.

The researchers used CT scanning techniques to get a new and detailed look at the child's skull (Skhul I), which consists of a broken braincase (neurocranium) and jaw (mandible). On further study, the braincase mostly exhibited modern features typical of Homo sapiens, but the jaw was more like a Neanderthal's, according to the study.

Study co-author Anne Dambricourt Malassé, a paleoanthropologist at the National Center for Scientific Research (CNRS) and National Museum of Natural History in France, told Live Science in an email that there was "no way" this morphology represents variability of Homo sapiens and the child was "objectively" a hybrid.

However, not everyone thinks the findings are so definitive. Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was not involved in the study, told Live Science that while the mandible looked primitive, when considering all of the fossils together, he thought they primarily aligned with Homo sapiens. But Stringer did note that the study's conclusions were consistent with a 2024 study suggesting that there was cross-population (or cross-species) gene flow between Neanderthals and humans about 100,000 years ago.

"Even if not 1st-generation hybrids, it's certainly possible that the Skhul fossils reflect some gene flow between the 2 populations," Stringer said in an email. "Overall though, looking at all the material including the skeletons, the material still primarily aligns with Homo sapiens, in my view."

Related: Stunning facial reconstructions of 'hobbit,' Neanderthal and Homo erectus bring human relatives to life

John Hawks, an anthropologist at the University of Wisconsin-Madison who wasn't involved in the study, told New Scientist that the study advances our understanding of the skull, but scientists can't definitively identify the child as a hybrid without extracting its DNA.

"Human populations are variable and there can be a lot of variability in their appearance and physical form even without mixing with ancient groups like Neanderthals," Hawks said.

Modern humans bred with Neanderthals, which is why most people alive today carry between 1% and 3% of Neanderthal DNA. However, researchers still have a lot to learn about this interbreeding, as well as how the ancient human family tree fits together.

Who was this ancient child?

Archaeologists first discovered human remains at Skhul Cave in 1928. Excavations uncovered the skeletons of seven adults and three children, which had been deliberately buried, along with bones linked to 16 other individuals. The bones were initially considered to be a transitional species between Neanderthals and modern humans. Researchers later suggested they were a hybrid between the two, but that assessment was also then rejected, and they ended up classed as anatomically modern humans, according to the study.

Skhul I belonged to a child, likely a female, between the ages of 3 and 5 years old. The middle section of the skull's face and a large part of the base were missing, while the rest was in pieces. In the past, archaeologists attempted to put the skull back together and consolidated the pieces with plaster, which made it more difficult for modern researchers to study. The new CT scans allowed researchers to virtually remove this plaster and compare the skull with other specimens.

The skull's modern human features include the vertical orientation of a bone on the side of the skull's base, while the jaw's Neanderthal-like features include a lack of chin.

Human evolution quiz: What do you know about Homo sapiens?

Four lifelike reconstructions of prehistoric humans have been unveiled — including a model of a species often dubbed "the hobbit," which, as an adult, was about the same height as a modern 4-year-old.

The 3D models are featured in the upcoming five-part documentary series "Human," which explores the extraordinary story of human evolution over the past 300,000 years, from our rise in Africa, to our migration into Eurasia and across the globe, including to our journey through the Americas after going along the Bering Land Bridge during the last ice age.

Scientists think that, in addition to Homo sapiens, at least six other human species existed around the time our species first emerged in Africa. The models from the series are based on three of these — Homo erectus, Homo floresiensis and Neanderthals — and the earliest known H. sapiens specimen.

"These are the most scientifically accurate collection of hyper-real 3D models of human species ever put on TV that we know of," paleoanthropologist and series presenter Ella Al-Shamahi said in a statement, adding that no TV show has brought this many ancient human species to life in such a way.

The production team for the series — a collaboration between the BBC Studios Science Unit and the U.S. science program "NOVA" — developed the 3D models using the latest available scientific data.

First, the team used hundreds of cameras to take photographs of actors who were chosen because their body shapes closely resembled the ancient humans being reconstructed, according to the statement. These images were then stitched together digitally to create a 3D model.

Related: Our mixed-up human family: 8 human relatives that went extinct (and 1 that didn't)

Next, the team adapted the 3D models to reflect the anatomy of each ancient human individual. They worked closely with the series' scientific consultants, who drew on the known fossil record to guide the reconstructions.

Finally, the team determined the skin and eye color of the models based on genetic studies of these ancient humans. The Neanderthal model, for example, features a light skin tone, as indicated by DNA evidence from genes linked to pigmentation. This light skin color would have helped Neanderthals with vitamin D production, as they lived at high latitudes in Eurasia that had low levels of sunlight.

The series will fly through human evolution, showing the diverse places and climates we've experienced and the extraordinary animals we encountered — and hunted — along the way. Al-Shamahi will introduce viewers to different types of archaic humans who lived throughout history.

For example, Homo erectus lived from at least 1.89 million to 110,000 years ago, originating in Africa before spreading into Asia and possibly parts of Europe. H. erectus was the first human species fully adapted for exclusively upright walking and is widely believed to have been the first human species to use fire.

Homo floresiensis is nicknamed "the hobbit" for its small size; it stood around 3.5 feet (1 meter) tall. This species inhabited the Indonesian island of Flores as recently as 50,000 years ago and is known to have used tools.

Neanderthals, with their cold-adapted bodies, first appeared more than 400,000 years ago, and lived across Europe, the Middle East and Central Asia, before going extinct around 40,000 years ago. They even bred with modern humans for thousands of years.

The early H. sapiens model, meanwhile, is based on fossils from Jebel Irhoud, Morocco, dated to about 300,000 years ago. These remains exhibit a mix of modern and archaic features and suggest an earlier origin for our species than previously believed.

"Human" will premiere in the United Kingdom Monday (July 14) on BBC Two, and all episodes will be available to stream on BBC iPlayer for U.K. residents only. The series will air in the United States on Sept. 17 at 9 p.m. ET/8 p.m. CT on PBS. It will also be available to stream at pbs.org/nova, NOVA on YouTube and the PBS app.

Editor's note: This article was updated on March 27, 2026 to note that the vast majority of Neanderthals went extinct 40,000 years ago, not 34,000 years ago as was previously stated.

Human evolution quiz: What do you know about Homo sapiens?

Neanderthals were running a potentially lifesaving "fat factory" around 125,000 years ago in what is now Germany, a new study finds.

The research, published Wednesday (July 2) in the journal Science, reveals that these archaic human relatives had a process for extracting grease from animal bones — and it may have saved them from a lethal condition.

The condition, known as protein poisoning or rabbit starvation, happens when humans eat too much protein and don't get enough fat or carbohydrates. Neanderthals would have likely been at high risk of protein poisoning, as they largely ate meat.

The "fat factory" discovery suggests that hominins, or humans and our close relatives, were practicing resource intensification — getting more utility out of the materials they had available — much earlier than previously thought. Before this analysis, the earliest evidence for resource intensification dated to 28,000 years ago, long after the Neanderthals' extinction, according to the study.

Scientists found the Paleolithic factory after uncovering the fragmented remains of 172 large animals, including horses, deer and cattle, as well as Neanderthal-made anvils and hammerstones. After analyzing the bones, the team found that Neanderthals had first smashed the bones to get to the marrow — a soft, edible tissue inside of some bones — before boiling them to extract the fat. It appears that Neanderthals ate both the marrow and the fat, which would have maximized the amount of food and nutrients they got from an animal carcass.

"It's surprisingly creative and innovative behavior from Neanderthals," Osbjorn Pearson, an archaeologist at The University of New Mexico who was not involved in the study, told Live Science.

Related: 10 fascinating discoveries about Neanderthals in 2024, from 'Thorin' the last Neanderthal to an ancient glue factory

Who were the Neanderthals?

Neanderthals, the closest extinct relative of modern humans, emerged around 400,000 years ago and went extinct around 40,000 years ago. Remains of the archaic humans were first discovered in the 19th century, and much of the archaeological evidence revealed since then suggests that Neanderthals were fairly sophisticated. They made tools, glue factories and possibly even art.

While it was known that Neanderthals largely ate meat, little was known about how Neanderthals prepared animal carcasses.

"We know a lot about Neanderthal hunting tactics, habits and consumption of meat and bone marrow … but to much lesser degree about all the processes after hunting and butchering," study first author Lutz Kindler, an archaeologist at the Monrepos Archaeological Research Center and Museum for Human Behavioral Evolution in Germany, told Live Science in an email.

"Labour-intensive and time-consuming"

Archaeologists found 2,000 bone fragments at Neumark-Nord, an archaeological site in central Germany, that had been crushed to facilitate the grease extraction.

"Fragmentation of the bones of large mammals into such a vast amount of small fragments is labour-intensive and time-consuming," so it's clear they served a purpose, study co-author Wil Roebroeks, a professor emeritus of paleolithic archaeology at Leiden University in the Netherlands, told Live Science in an email. In addition to bearing signs of being boiled, the bones are mostly broken near areas that contain the most fat, which supports the idea that the grease was rendered for consumption.

Neanderthals might have eaten the fat out of necessity, Pearson said. They sometimes experienced periods of starvation and may have been desperate for sources of calories. "And it turns out that fat is just packed with calories," he said — fat supplies more than twice the calories per gram as carbohydrates and protein do.

The bones also suggest that these archaic humans may have used some form of food storage, Roebroeks said. Neanderthals may have been "more similar to historically documented foragers" than previous research had suggested, he added.

Kindler noted the overlaps between the revealed Neanderthal practice and modern human behavior. "The archaeological science of studying hominids is about finding the similarities between us today and them in the past," he said.

Understanding what Neanderthals ate and how they acquired it may improve our understanding of human adaptations, Roebroeks said. The extra calories provided by bone-derived grease has been vital to human evolution, as more robust diets can lengthen lifespan and lead to increased reproduction.

Editor's note: This article was updated on March 27, 2026 to note that the vast majority of Neanderthals went extinct 40,000 years ago, not 34,000 years ago as was previously stated.

Neanderthal quiz: How much do you know about our closest relatives?

Before modern humans began their major dispersal out of Africa about 50,000 years ago, they moved to places that were significantly more ecologically diverse, which may have given them the flexibility they needed to migrate across the globe, a new study finds.

Our species, Homo sapiens, originated in Africa more than 300,000 years ago. Genetic evidence suggests that all modern human populations outside Africa mostly descend from a small group of modern humans who started migrating out of Africa about 50,000 years ago.

However, previous research suggests the first waves of Homo sapiens began leaving Africa as early as about 270,000 years ago. This raises the question of why these earlier migration waves left no genetic traces in modern human populations outside Africa today.

In the new study, published Wednesday (June 18) in the journal Nature, researchers analyzed evidence from archaeological sites across Africa dated to between 120,000 to 14,000 years ago. By examining ancient plant and animal remains, the scientists reconstructed what kinds of habitats and climates people lived in across that span of time — this painted a picture of the vegetation, temperatures and rainfall a given area might have had.

The researchers discovered that modern humans began to expand the range of habitat types in which they lived starting about 70,000 years ago — they went into forests in West and Central Africa, deserts in North Africa, and places with greater ranges of annual temperatures.

"Humans have been successfully living in challenging habitats for at least 70,000 years," study co-lead author Emily Hallett, an archaeologist at Loyola University Chicago, told Live Science.

Related: When did Homo sapiens first appear?

This discovery "was a huge surprise" and sheds light on why the last major dispersal of modern humans from Africa proved successful, study co-senior author Eleanor Scerri, an evolutionary archaeologist at the Max Planck Institute of Geoanthropology in Germany, told Live Science.

"Our ecological flexibility is part of what enabled our species to disperse across the globe and thrive in each habitat we encountered," Hallett said.

Modern humans were pretty good generalists from the very beginning, inhabiting a wide range of habitats, noted study co-senior author Andrea Manica, an evolutionary ecologist at the University of Cambridge.

"What we see about 70,000 years ago is Homo sapiens becoming the ultimate generalist, and pushing into more and more extreme environments," Manica told Live Science. "That newly found additional flexibility gave them an edge 50,000 years ago, allowing them to spread rapidly across the whole globe, and thriving in environments that were novel and sometimes very challenging, such as those found at very northern latitudes."

The greater ecological flexibility the researchers saw in modern humans was likely not the result of a single evolutionary adaptation or technological innovation, said study co-lead author Michela Leonardi, an evolutionary biologist at the University of Cambridge. Instead, it looks more like the complex interaction of many factors, such as modern human populations living across larger ranges, experiencing greater levels of contact and cultural exchanges between groups, "and a higher likelihood of developing and maintaining innovations," she told Live Science.

These new findings may shed light not just on the journey of modern humans out of Africa, but human evolution in general, including ancient lineages in the genus Homo like Homo erectus and the closest extinct relatives of modern humans, the Neanderthals and Denisovans, said William E. Banks, an archaeologist at the French National Center for Scientific Research who did not take part in this study but wrote an editorial about it, which was also published in the journal Nature on June 18.

"Earlier members of our genus must have also expanded the range of environmental conditions that they occupied when they left Africa and began to permanently occupy regions of Eurasia," Banks told Live Science.

It remains uncertain why modern humans began expanding to more challenging habitats about 70,000 years ago, Scerri said. One possibility is that the spaces in which they had lived were shrinking, although it's unknown why at this point — "it was likely out of necessity," she said.

Human evolution quiz: What do you know about Homo sapiens?

Using cutting-edge DNA analysis, scientists have uncovered the true identity of an ancient human relative nicknamed the "Dragon Man."

The mystery began with a giant, human-like skull discovered by a Chinese laborer in Harbin City, China, in 1933. In 2018, the man's family recovered the Harbin skull, which the laborer had buried in a well, and donated it to science. The enormous cranium features a long, low braincase and a massive brow ridge, along with a broad nose and big eyes. Based on the skull's unusual shape and size, experts gave it a new species name — Homo longi, or "Dragon Man" — in 2021.

But in the past several years, there has been intense debate about whether Dragon Man, who lived at least 146,000 years ago, is a separate species. Instead, some researchers have claimed that the Dragon Man skull may be from a group of ancient humans called the Denisovans, since no Denisovan skull had ever been found.

Now, in two studies published Wednesday (June 18) in the journals Science and Cell, researchers have proved that Dragon Man is indeed the face of Denisovans.

Scientists first attempted to retrieve an ancient genome from the bones and teeth of the Harbin skull, without success. But they were able to recover some DNA from plaque that had hardened on the teeth and some information on proteins from an inner ear bone.

Mitochondrial DNA (mtDNA), which is passed from mother to child, recovered from the skull showed that Dragon Man was related to an early Denisovan group that lived in Siberia from around 217,000 to 106,000 years ago, which means that Denisovans inhabited a large geographical range in Asia, the researchers wrote in the Cell study.

Additionally, the researchers investigated the skull's "proteome," the set of proteins and amino acids found in the skeleton. By comparing the proteome to those of contemporary humans, Neanderthals, Denisovans and nonhuman primates, the researchers found a clear connection between the Harbin cranium and early Denisovans, they wrote in the Science study.

Related: 43,000-year-old human fingerprint is world's oldest — and made by a Neanderthal

"We now have the first comprehensive morphological blueprint for Denisovan populations, helping to address an unresolved question that has persisted over the last decade on what Denisovans looked like," they wrote in the Science study. In short, Denisovans looked like Dragon Man.

While the mystery of the enormous skull has been largely resolved, experts still need to discuss its assignment to the H. longi species.

"This work makes it increasingly likely that Harbin is the most complete fossil of a Denisovan found so far," Chris Stringer, a paleoanthropologist at the Natural History Museum in London who has worked on the Harbin cranium but was not involved in these new studies, told Live Science in an email. Stringer added that "Homo longi is the appropriate species name for this group," although at this point, the group is small.

But Harbin's new identification as a Denisovan also requires experts to reconsider what they thought they knew about the evolution of humans in Asia, particularly in the Middle Pleistocene epoch, around 789,000 to 126,000 years ago. During this period, Eurasia was home to at least three different hominins — humans, Neanderthals and Denisovans — that frequently mated with one another, giving rise to the "muddle in the middle" nickname for this confusing period of evolution.

Until now, the Denisovan group of early humans has been known mostly from their DNA and a tiny handful of fossils. This is in stark contrast to Neanderthals, whose skulls have been found throughout Europe and Western Asia for more than 150 years.

With the identification of the Harbin skull as Denisovan and the identification of a jawbone found off the coast of Taiwan as Denisovan in a study published in the journal Science in April, this means paleoanthropologists have definitive examples that other unknown skulls can be compared to.

Studies of the size and shape of Middle Pleistocene fossil skulls will remain crucial for testing relationships, Stringer said, particularly because DNA does not preserve well in most fossils, and these studies are important for identifying what Denisovans actually looked like. But "there is certainly much more to come from extractions of ancient DNA and proteomes from human fossils," Stringer said.

Human evolution quiz: What do you know about Homo sapiens?

A red dot on a face-shaped rock in Spain may be setting records in more ways than one. At roughly 43,000 years old, the dot may be the oldest human fingerprint on record and also one of the earliest symbolic objects ever found in Europe.

The fingerprint, made with the red mineral ocher, was left by a Neanderthal — the closest extinct relative of modern humans. Neanderthals went extinct around 40,000 years ago but occupied Europe for hundreds of thousands of years before early modern humans arrived on the continent.

The researchers behind a new study argue that the red dot represents a nose on a rock with face-like features. The discovery is a further challenge to the idea that Neanderthals were generally not capable of symbolic art.

But some experts told Live Science they are not convinced that the dot is symbolic.

Anthropologist and archaeologist Bruce Hardy of Kenyon College in Ohio, who was not involved in the discovery, said the red dot was definitely deliberate but little more could be certain beyond that.

"Clearly, the ocher has been intentionally applied with the fingerprint," Hardy told Live Science. "But I did not see a face — symbolism is in the eye of the beholder."

Related: 130,000-year-old Neanderthal-carved bear bone is symbolic art, study argues

The study, published May 5 in the journal Archaeological and Anthropological Sciences, describes the 2022 discovery at the San Lázaro rock shelter on the outskirts of Segovia in central Spain.

Scientists have evidence that the region was heavily populated by Neanderthals between 44,000 and 41,000 years ago, but there is no evidence that early modern humans ever lived there.

Ancient face?

The rock, which resembles a large potato, is about 6 inches (15 centimeters) long and has vaguely eyebrow-shaped indentations near one end.

But the deliberate addition of a red dot for a "nose" beneath the "eyebrows" of the rocky Mr. Potato Head transforms the large pebble into a primitive portrayal of a human face, the authors argue.

"This find represents the most complete and oldest evidence of a human fingerprint in the world, unequivocally attributed to Neanderthals, highlighting the deliberate use of the pigment for symbolic purposes," Spain's National Research Council (CSIC) said in a translated statement.

The red dot looks evenly spread, but forensic examinations and analysis of how it reflected different wavelengths of light revealed it was created by a fingerprint with a distinctive whorl pattern, probably from an adult male Neanderthal.

The granite pebble seems to have been deliberately brought to the rock shelter, probably from a nearby river where it formed. "The fact that the pebble was selected because of its appearance and then marked with ocher shows that there was a human mind capable of symbolizing, imagining, idealizing and projecting his or her thoughts on an object," the team of researchers wrote in the study.

Stone Age art

Debate about whether Neanderthals made abstract art has raged among archaeologists for decades. Finds include engravings on cave walls in France that may be up to 75,000 years old, but even the finest works of Neanderthal art pale next to the cave paintings made by early modern humans at sites like the Chauvet Cave in France and on the island of Sulawesi in Indonesia.

Rebecca Wragg Sykes, a paleolithic archaeologist at the universities of Cambridge and Liverpool in the U.K. and the author of "Kindred: Neanderthal Life, Love, Death and Art" (Bloomsbury Sigma, 2020), thinks that, even if red dot is symbolic, it is possible that the study's authors may have misunderstood its meaning.

"What the team infer to be a representation of a nose on a face might, if turned the other way up, be seen as a navel on a human figure," she told Live Science in an email. "We can't really say what it is meant to 'be.'"

Durham University archaeologist Paul Pettitt, who also was not involved in the discovery, said the rock was an "unequivocal example of the Neanderthal use of red pigment" that showed how Neanderthals were routinely leaving marks on cave walls and portable objects. But whether the red dot was truly symbolic of something or not was still unclear, he said.

And the archaeologist and psychologist Derek Hodgson, an expert in prehistoric cave art who also was not involved in the study, told Live Science that the rock seemed to have had no other purpose. Additionally, the rock only looked like a face when the "nose" mark was added, he said in an email.

"This find adds to the growing corpus of objects made by the Neanderthals that are non-functional in nature."

Neanderthal quiz: How much do you know about our closest relatives?

Bones from an extinct human ancestor have been recovered from the seafloor, revealing a previously unknown Homo erectus population in Southeast Asia that may have interacted with more modern humans, new studies find.

The H. erectus bones were among a cache of more than 6,000 animal fossils hoovered up as part of a construction project off the island of Java in Indonesia. This is the first time scientists have seen fossils from the submerged parts of the Indonesian archipelago, which connected islands like Java to the Asian mainland during the last ice age, when sea levels were lower.

These lost lands, called drowned Sundaland, were once vast open plains interspersed with rivers around 140,000 years ago. The newly discovered fossils revealed the rivers were teeming with fish, turtles, river sharks, hippos and other marine life, while terrestrial giants such as elephants, the elephant-like Stegodon and water buffalo populated the plains, according to the studies.

H. erectus' presence on this landscape confirms that our ancient ancestor was taking advantage of drowned Sundaland's fertile hunting grounds, at least between Java and another, smaller island called Madura. This region, once a valley, is now submerged in a body of seawater called the Madura Strait.

The researchers found cut marks on some of the fossils that confirmed the Madura Strait hominins (humans and our close relatives) were hunting turtles — the earliest evidence of this in Southeast Asia — and large game. The remains also suggested that these hominins were selectively targeting cow-like bovids in their prime, which Indonesian H. erectus isn't known for. This hunting strategy is associated with more modern humans on the Asian mainland, raising the possibility that the newly discovered H. erectus population copied the strategy from other human relatives.

"The Madura Strait hominins may have developed this hunting strategy independently," study lead author Harold Berghuis, a researcher studying H. erectus at Leiden University in the Netherlands, told Live Science in an email. "But the other possibility is that we are looking at a kind of cultural exchange."

The researchers shared their findings in four separate studies published last week in the journal Quaternary Environments and Human.

Related: Ancient quarries in Israel reveal where Homo erectus hunted and butchered elephants

H. erectus is an important part of our evolutionary history. Emerging at least 2 million years ago, it was the first species to develop human-like body proportions and the first human species to migrate out of Africa, eventually finding its way to Southeast Asia. Other ancient humans followed in H. erectus' footsteps, but the extent to which these different species interacted in Southeast Asia is unknown, and the genetics of these different hominins is uncertain.

The human family tree is complicated, particularly in Southeast Asia. Berghuis noted that by around 350,000 years ago, H. erectus was being replaced on what is now the Asian mainland by a more modern human population, which included the mysterious Denisovans and the Neanderthals.

Fossil evidence suggests that H. erectus continued to survive on the island of Java until around 117,000 to 108,000 years ago, when the species eventually went extinct. Our species, H. sapiens, arrived in Southeast Asia around 77,000 years ago.

Fossil island dream

The latest fossil discovery was uncovered because of a large construction project in the Madura Strait. From 2014 to 2015, contractors pulled around 177 million cubic feet (5 million cubic meters) of sand and sandstones from the seabed near the port city of Surabaya to create an artificial island, according to one of the new studies published May 15.

To remove the sediment, the contractors used a trailing suction hopper dredger, which is a ship that drags a steel structure along the seabed, breaking up the sediment and mixing it with water. A suction pipe then hoovered up the sediment. This process, called dredging, can negatively impact marine life, but the amount of damage varies depending on the location and the species involved — invertebrates, eggs and larvae are most vulnerable to the practice. Berghuis noted that under Indonesian legislation, the dredging was subject to environmental impact assessments and supervision.

The hoovered-up sediment was discharged at a land reclamation site to create a 250-acre (100 hectare) sandy island. Berghuis had access to the site as a geotechnical consultant for the port of Surabaya, and spent many weeks searching on hands and knees for fossils. He told Live Science that he "dreamed" of finding a hominin fossil, but it wasn't until his very last day of collecting that he finally spotted one.

"It was already getting dark and I sat down to enjoy [the] sunset," Berghuis said. "And then, right beside me, lay this fossil that reminded me so much of the only Dutch Neanderthal. This is a well-known fossil in my country, dredged from the North Sea."

Berghuis took the fossil, a skull fragment, back to his hotel room and compared it with images of the famous Dutch Neanderthal. Its pronounced brow ridge was similar to Neanderthals and other ancient humans. Berghuis and his colleagues later determined it belonged to an adult or adolescent H. erectus.

The team also identified another H. erectus skull fragment in the fossils Berghuis recovered. Based on the thickness of the second fragment, the team determined this individual had not reached adulthood, according to one of the studies. The researchers couldn't determine how the individuals died.

Related: When did modern humans reach each of the 7 continents?

Land of dragons

The H. erectus discovery was just the tip of a mountain of findings documented in the new studies. Researchers identified 36 different species in a total of 6,372 recovered fossils. These included fossils of Komodo dragons (Varanus komodoensis).

Komodo dragons are giant lizards capable of (slowly) killing large animals, including water buffalo, with bacteria and venom-laced bites. Today, they are an endangered species restricted to a few Indonesian islands, but the new studies suggest they could have ruled the Sundaland plains.

"Komodo dragons may have been the most important predators," Berghuis said.

A mysterious human jaw discovered off the coast of Taiwan doesn't belong to our species or Neanderthals, but to another extinct relative, Denisovans.

In a new study, researchers used a cutting-edge technique that analyzes proteins to determine which species the jawbone belonged to, which had been a mystery since its discovery in the early 2000s off the west coast of Taiwan. Their approach showed that the individual was Denisovan, a "cousin" of Neanderthals and humans that roamed throughout Asia during the Pleistocene epoch, and it opens the door to identification of unknown human fossils.

"The same technique can and is being used to study other hominin fossils to determine whether they too are Denisovans, Neanderthals or other hominin populations," study co-author Frido Welker, a molecular anthropologist at the University of Copenhagen, told Live Science.

Welker and an international team of experts wanted to better understand the Penghu 1 jawbone, a specimen that was netted by a fisherman from the floor of the Penghu Channel, roughly 15.5 miles (25 kilometers) off the west coast of Taiwan. In the decade since Penghu 1 was documented, paleoanthropologists have disagreed on whether the robust jaw with large teeth came from a Homo erectus, an archaic Homo sapiens, or a Denisovan.

Denisovans are extinct human relatives who lived at the same time as Neanderthals and Homo sapiens. But unlike Neanderthals, whose bones have been found throughout Europe and western Asia for more than a century, Denisovans are mostly known from DNA, since only a handful of fossils have ever been found, most of which come from Denisova Cave in Siberia. Without a large collection of fossils, it is difficult for experts to identify new Denisovan skeletons and to figure out where they lived and how they’re related to humans.

Related: 'Mystery population' of human ancestors gave us 20% of our genes and may have boosted our brain function

Using the relatively new technique of paleoproteomics, or the analysis of ancient proteins, the research team showed that Penghu 1 was male and that his particular suite of amino acids and proteins was most similar to Denisovans. They published their findings April 10 in the journal Science.

"It wasn't possible to make real meaning of this specimen even 8 or 9 years ago," Sheela Athreya, a biological anthropologist at Texas A&M University who was not involved in the study, told Live Science. "This study confirms what we always inferred — that there has been hominin presence in the farthest extent of eastern Eurasia throughout the Pleistocene."

Dating conundrum

One limitation to the new study, however, is that Penghu 1 can’t be dated confidently using traditional methods such as carbon-14 or uranium dating because the specimen was waterlogged for so long, and DNA extraction attempts also failed.

Animal bones found with the jawbone suggest two age ranges, Welker said — either 10,000 to 70,000 years ago or 130,000 to 190,000 years ago. "If the specimen falls into the younger age range, it could potentially be the youngest Denisovan found to date," he added. Currently, the youngest Denisovan fossil is 40,000 years old and was found on the Tibetan Plateau.

But even with the uncertainty in exact dates, the identification of Penghu 1 as a Denisovan shows that these groups were widely distributed throughout Asia, from frigid regions like Siberia to warm and humid areas like Taiwan.

"It is now clear that two contrasting hominin groups – small-toothed Neanderthals with tall but gracile mandibles and large-toothed Denisovans with low but robust mandibles," the researchers wrote in the study, "coexisted during the late Middle to early Late Pleistocene of Eurasia."

This conclusion shines a light on the diversity and evolution of Homo, and the researchers’ next steps will be to use paleoproteomics to identify more archaic bones from the genus.

"The meaningful result of this work is that we can do so much more with previously unprovenienced fossils found in channels and riverbeds in Asia," Athreya said. "That's exciting!"

Editor's note: This story was first published on April 10, 2025.

Neanderthal quiz: How much do you know about our closest relatives?

Modern humans have uniquely small and flat faces, especially compared with our Neanderthal cousins' notoriously robust faces and large noses, but the reason for this difference has eluded paleoanthropologists. Now, researchers have determined that human faces grow slowly and stop growing during early adolescence, whereas Neanderthals' faces kept growing into early adulthood.

"These two human species followed different developmental trajectories for their facial bones," Alexandra Schuh, a postdoctoral researcher at the Max Planck Institute for Evolutionary Anthropology in Germany, told Live Science.

In a study published Monday (March 24) in the Journal of Human Evolution, Schuh and colleagues analyzed the midface region of 174 skulls of Homo sapiens, Neanderthals and chimpanzees. By including skulls from individuals throughout childhood and into adulthood, the researchers were able to investigate facial ontogeny — how the facial bones of the skull develop and grow.

The researchers used two techniques to closely examine the skulls. First, they created virtual 3D models of the skulls and digitized over 200 landmarks on the upper jawbone to look at patterns of growth and development. Then, they undertook microscopic analysis to look for bone formation and bone resorption, a normal process in bone remodeling that helps the tissue retain its structure and strength.

Related: 28,000-year-old Neanderthal-and-human 'Lapedo child' lived tens of thousands of years after our closest relatives went extinct

"We found that bone formation is predominant in Neanderthals — from birth on — who develop larger and more projecting faces," Schuh said. "In contrast, present-day humans exhibit significantly higher levels of bone resorption."

The new research showed that both chimpanzees and Neanderthals had larger, faster-growing faces, while modern humans have smaller faces that stop growing sometime during adolescence.

"Earlier growth cessation is a distinctive feature of our species," Schuh said. "We have identified a unique developmental pattern seen exclusively in Homo sapiens."

Experts have put forth numerous explanations for why Neanderthals had such large faces and noses, including adaptation to a cold climate, higher energy needs, the chewing of tough foods, and the use of their teeth as tools. Explanations for humans' small faces, on the other hand, include the invention of cooking and increases in brain size.

But the reason humans evolved these uniquely small faces is a particularly complex question in paleoanthropology that has not yet been solved. "However, our study addresses aspects of the 'how,'" Schuh said, "providing an important first step toward understanding these processes."

Neanderthal quiz: How much do you know about our closest relatives?

The ancestors of all modern humans split off from a mystery population 1.5 million years ago and then reconnected with them 300,000 years ago, a new genetic model suggests. The unknown population contributed 20% of our DNA and may have boosted humans' brain function.

"The fact that we can reconstruct events from hundreds of thousands or millions of years ago just by looking at DNA today is astonishing, and it tells us that our history is far richer and more complex than we imagined," study co-author Aylwyn Scally, a geneticist at the University of Cambridge, said in a statement.

In a study published Tuesday (March 18) in the journal Nature Genetics, researchers presented a new method of modeling genomic data, called "cobraa," that has allowed them to trace the evolution of modern humans (Homo sapiens).

By applying their new method to modern human DNA data published in the 1000 Genomes Project and the Human Genome Diversity Project, the researchers discovered that there were two main ancestral groups that split around 1.5 million years ago, which they called Population A and Population B.

Just after that split, Population A experienced a bottleneck when the population plummeted and likely lost a significant amount of genetic diversity. But Population A grew over time, and Neanderthals and Denisovans branched off from it.

Related: Human ancestors arrived in Western Europe much earlier than previously thought, fossil face fragments reveal

Then, around 300,000 years ago, Population A mixed with Population B, the researchers found. Their genetic analysis suggests that 80% of the genome of all present-day humans comes from Population A, while 20% of our genome comes from Population B.

Some of the genes from Population B, "particularly those related to brain function and neural processing, may have played a crucial role in human evolution," study co-author Trevor Cousins, a postgraduate student in genetics at the University of Cambridge, said in the statement. In general, the genetic material from Population B reduced the ability of individuals to have children, Cousins told Live Science in an email, but "the genome is a complicated place, and regions outside of genes can still do important things."

The new model suggests that, around 300,000 years ago, Population A, which eventually gave rise to humans, had "deep structure," Cousins said, meaning it was formed from "two or more genetically distinct populations that mixed with each other."

Who those populations were, however, is not clear. In the study, the researchers noted that "various Homo erectus and Homo heidelbergensis populations that are potential candidates for lineages A and B existed both in Africa and elsewhere in the relevant period."

But "the genetic model cannot indicate which fossils should be assigned to Population A or B," Cousins said. "We can only speculate."

Some experts use the term "ghost populations" to talk about groups that branched off and then reconnected later through interbreeding resulting in gene flow, John Hawks, a biological anthropologist at the University of Wisconsin-Madison who was not involved in the study, told Live Science by email.

"What is interesting about this paper is that the pattern in the model is a deep African structure that is shared by everyone living today," Hawks said. "It is not 'ghost populations' contributing to one particular group, it is one big ghost that merged in with the African source population for all modern humans."

But one of the drawbacks to the new model, according to Hawks, is that it is based on the 1000 Genomes Project, which has a low representation of African populations. "So I see this as more a proof of principle than a real guide to what ancient humans were doing," Hawks said.

The origin of modern humans is a long-standing question in paleoanthropology, and improvements in DNA and genomic analysis in the past two decades have provided new insights and raised new questions.

"What's becoming clear is that the idea of species evolving in clean, distinct lineages is too simplistic," Cousins said in the statement. "Interbreeding and genetic exchange have likely played a major role in the emergence of new species repeatedly across the animal kingdom."

Human evolution quiz: What do you know about Homo sapiens?

Archaeologists in Israel have discovered five burials in a cave belonging to an enigmatic human lineage that suggest this group shared aspects of its lifestyle, technology and burial customs with modern humans and Neanderthals, who also lived in the region up to 130,000 years ago, a new study reports.

The finding reveals that Neanderthals, modern humans and related human lineages coexisted in what is now Israel for about 50,000 years. However, it's unknown which group influenced the other and in what direction.

In the new research, scientists investigated caves in the Levant — the eastern Mediterranean region that today includes Israel, the Palestinian territories, Jordan, Lebanon and Syria. Researchers have long thought the Levant was a key gateway for our species, Homo sapiens, and other branches of the human family tree that migrated out of Africa.

Prior work suggested that during the mid-Middle Paleolithic (80,000 to 130,000 years ago), the southern Levant was home to at least three different groups of Homo: modern humans, Neanderthals and a third lineage resembling both modern humans and Neanderthals that was unearthed at the prehistoric site of Nesher Ramla in central Israel. Although these groups were physically different from one another, researchers weren't sure how similar they were in terms of lifestyle.

Artifacts found at Nesher Ramla suggested that the site had been a temporary hunting and butchering camp, so the researchers looked nearby for the main base of operations. "Such sites are usually found in caves," study lead author Yossi Zaidner, a Paleolithic archaeologist at the Hebrew University of Jerusalem, told Live Science.

Zaidner and his colleagues focused on Tinshemet Cave about 6 miles (10 kilometers) away from Nesher Ramla. Scientists first discovered the cave in 1940, and new excavations there unearthed five burials belonging to Homo — the first such burials from the mid-Middle Paleolithic found in this region in more than 50 years. It's currently unknown if these burials belong to early modern humans, human-Neanderthal hybrids, the mysterious other lineage or another group entirely.

Related: Neanderthals and early Homo sapiens buried their dead differently, study suggests

The researchers also uncovered stone artifacts made with the Levallois technique, meaning they are humped on one side, flat on the other and had sharpened edges. In addition, the human remains were buried in fetal positions, often with the red mineral pigment ocher, which prior research suggested was linked with funerary practices and symbolic thought. The scientists also discovered bones of large game such as aurochs (Bos primigenius, an extinct cowlike species), horses, deer and gazelles.

"The discoveries at Tinshemet Cave are probably going to be the most important finds in the region from the last 50 years," Chris Stringer, a paleoanthropologist at the Natural History Museum in London who was not involved in the new study, told Live Science.

Multiple humans at multiple caves

These findings at Tinshemet Cave were very similar to discoveries made in two other caves in Israel — Skhul Cave and Qafzeh Cave — that also date to the mid-Middle Paleolithic. However, the skeletal remains in each cave were significantly anatomically distinct from those of the other caves.

The researchers suggest that different groups of Homo not only coexisted in the mid-Middle Paleolithic in the Levant, but shared a number of key practices, exchanging innovations such as burial rites and the symbolic use of ocher for about 50,000 years. It remains uncertain in which direction these practices were exchanged — say, if modern humans adopted Neanderthal hunting strategies, or if Neanderthals embraced modern human burial rites, or if they came up with new practices together.

"Neanderthals' and Homo sapiens' interactions were not just sporadic encounters, but they had very substantial contacts which led to adoption of behaviors," Zaidner said.

The fact that groups of Homo from this time and place often share anatomical features of both modern humans and Neanderthals suggest "these are actually hybrids that are using the same culture," Zaidner said.

However, Stringer does not see a mixing of lifestyles. Instead, he suggested the burials and artifacts at the Tinshemet, Skhul and Qafzeh caves are linked only with H. sapiens, and that different behaviors discovered at later Levant sites such as the Kebara, Amud and Dederiyeh caves are linked with Neanderthals.

"That said, there is growing evidence that these populations overlapped in the region about 100,000 years ago more than has been supposed, and given what happened in Europe 50,000 years later, there was clearly potential for contact and both cultural and genetic exchanges," Stringer said. "I've tended to play down the possibility that the Skhul and Qafzeh samples show signs of hybridization with Neanderthals, but they do show a lot of morphological variation, and some of it could indeed be an indication of interbreeding with Neanderthal neighbors."

The scientists now plan to study the remains at Tinshemet Cave in greater detail to see if they are hybrids of modern humans and Neanderthals, Zaidner said.

"I eagerly await detailed descriptions of the morphology of the Tinshemet fossils," Stringer said. If interbreeding between modern humans and Neanderthals did happen in the Levant, "and I agree it seems increasingly likely, then somewhere there must be actual first-generation Neanderthal-sapiens hybrids waiting to be discovered or recognized," Stringer added.

The researchers detailed their findings online Tuesday (March 11) in the journal Nature Human Behavior.

A large proportion of East Asian people carry unique versions of the lactase gene that enables humans to digest the sugars in milk, new research hints.

These genetic variants were likely inherited from humans' extinct cousins, the Neanderthals, tens of thousands of years ago, according to a study published Mar. 10 in the journal PNAS. And it may be that the variants offered an evolutionary advantage by helping early hunter-gatherers thwart infections, new data suggest.

In some people of European or African descent, the lactase gene helps carriers digest a sugar called lactose in milk after they're weaned off of breast milk; this phenomenon is known as "lactase persistence." Many people who carry alternative versions of the gene can't continue breaking down lactose after infancy, so they become lactose intolerant.

The versions of the lactase gene behind lactase persistence are believed to have emerged in populations in Europe and Africa between 5,000 and 10,000 years ago, around the same time humans on these continents began rearing animals and consuming their milk.

Related: Papua New Guineans, genetically isolated for 50,000 years, carry Denisovan genes that help their immune system, study suggests

This has led scientists to theorize that the lactose-tolerance variants were selected for within these populations, meaning they became more common over the course of evolution because they offered an advantage. In this case, they may have increased survival rates by allowing adults to absorb nutrients from milk.

However, until now, little was known about the genetic mechanisms behind lactase persistence and lactose intolerance in East Asians. About 65% of adults worldwide are thought to be lactose intolerant, but this figure rises to between 70% and 100% in East Asian populations.

In the new study, scientists compared thousands of genomes sampled from modern humans, including those with East Asian, European or African ancestry. The data came from individuals in a range of countries, such as China, Japan, Spain, Italy and Nigeria.

The analysis revealed that around 25% of the people with East Asian ancestry carried versions of the lactase gene that are not found within the European or African populations. That's around the same proportion of people who have lactase persistence in East Asian populations. These genetic variants trigger an increase in the activity of the lactase gene in the body, the researchers found.

At first glance, this suggests that these genetic variants may have also been selected for during evolution for dietary reasons, the researchers said. However, further analyses in the same study revealed that this may not have been the case.

Indeed, the researchers went on to compare samples of East Asian genomes with the genome of a Neanderthal who lived in the Altai Mountains in Siberia around 120,000 years ago. This led them to discover that the East Asian variants of the lactase gene were likely inherited by hunter-gatherers from Neanderthals as a result of interbreeding events between the two groups.

Neanderthals and Homo sapiens are known to have interbred on multiple occasions over the millennia. This happened after both species came into contact with one another following the migration of the latter group out of Africa into Eurasia, possibly up to 250,000 years ago.

The new results suggest that the lactose-intolerance variants started being selected for between 25,000 and 28,000 years ago — more than 10,000 years before dairy culture emerged in the Altai Mountain region.

In other words, the variants emerged before people in the region started regularly consuming milk. This suggests that the selective pressure on these variants was not related to improving people's ability to digest lactose.

To figure out what other advantages these variants might offer, the team scoured a database chronicling gene activity in different cells. They discovered that the lactase gene variants seen in East Asian people altered the activity of three genes in immune cells, causing them to expand in number.

Based on this result, the study authors think it's possible that these variants were selected for because they somehow enhanced the ability of East Asian hunter-gatherers to combat infections.

"Neanderthals — having inhabited Eurasia for approximately 400,000 years — likely carried alleles [genetic variants] adapted to local pathogens and environmental challenges," study co-author Shuhua Xu, a professor of human population genetics at Fudan University in China, told Live Science in an email.

Taken together, the findings imply that variants of the lactase gene may have been selected for different reasons across the world, the researchers concluded. These findings may prompt scientists to question why selection of the lactase gene occurred in European and African populations, they added; perhaps the answer isn't solely about drinking milk.

The skeleton of a child with both Neanderthal and modern-human features has been dated to around 28,000 years ago, according to new research that used a new chemical method to pull off the feat.

The new dates, which range from 25,830 to 26,600 B.C., change what archaeologists initially thought about the burial rituals surrounding the "Lapedo child" in what is now Portugal.

"The death of the child may have triggered a declaration of the place as taboo or as unsuitable for mundane hunting activities, leading to people avoiding it until such time as the event faded from social memory," João Zilhão, an archaeologist at the University of Barcelona, told Live Science in an email. Zilhão and colleagues published the new dates Friday (March 7) in the journal Science Advances.

The child's skeleton was discovered in 1998 in the Lagar Velho rock-shelter in the Lapedo Valley of central Portugal. When paleoanthropologists removed the bones from the dirt, they immediately noticed that the child's skeleton had a "mosaic" of Neanderthal and human features, suggesting it was a hybrid individual. For example, the child had a prominent chin like humans' but short, stocky legs like Neanderthals'.

In the late 1990s, the discovery of a hybrid child and associated burial ritual was not immediately accepted as a valid interpretation of the Lapedo site. The Lapedo child was found a decade before the first Neanderthal genome was sequenced — a feat that paved the way for a better understanding of interbreeding between humans and our extinct cousins. We now know from ancient DNA that Neanderthals and humans interbred multiple times over thousands of years.

Related: Did we kill the Neanderthals? New research may finally answer an age-old question.

One issue that has plagued researchers' study of the Lapedo child is the difficulty of dating it. Four previous attempts were made using traditional radiocarbon-dating methods to narrow down the time frame of the burial, but problems with poor preservation and methodology could produce only a broad range of 20,000 to 26,000 years before present — much more recent than expected based on dates from nearby animal bones.

But using a novel method called compound-specific radiocarbon analysis (CSRA), researchers have determined that the Lapedo child lived thousands of years earlier than initially thought.

Study first author Bethan Linscott, a geochemist at the University of Miami, told Live Science in an email that, although the CSRA method has been around awhile, it's only recently been used to redate Neanderthal sites where modern carbon has contaminated the ancient samples.

"The key benefit of compound-specific radiocarbon dating is that it is extremely efficient at removing contamination from archaeological bones," Linscott said. "This is especially important when dealing with poorly preserved bones because even trace amounts of contamination present in such samples can seriously impact the accuracy of the date."

Bunny bones

The team then took their research a step further by redating three things that excavators assumed were part of the Lapedo child's burial ritual: a young rabbit whose bones were found on top of the child, red deer bones discovered near the child's shoulder, and charcoal underneath the child's legs that was assumed to have been a ritual fire.

The researchers discovered, however, that only the rabbit bones were contemporaneous with the Lapedo child, while the charcoal and red deer bones were much older, suggesting they were already present at the site when the child was buried.

As a result of the new dating technique, the researchers hypothesized that the bunny was placed on top of the shrouded body of the Lapedo child as an offering before the grave was filled roughly 28,000 years ago. The site was then abandoned for at least two millennia.

"While we do not have any genetic evidence from Lagar Velho, providing additional confirmation on the age of the site allows us to better understand, on the basis of morphology, how the process of replacement of Neanderthals by Homo sapiens may have played out," Adam Van Arsdale, a paleoanthropologist at Wellesley College who was not involved in the study, told Live Science by email.

Researchers are figuring out the exact amount of overlap in time between the two groups and whether specific features shared from one group to the other were advantageous, especially given that Neanderthals went extinct around 40,000 years ago but modern humans persisted.

Neanderthal quiz: How much do you know about our closest relatives?

Neanderthals may have been headed toward their demise much earlier than experts previously thought, new research suggests.

In the study, published online Feb. 20 in the journal Nature Communications, researchers discovered that around 110,000 years ago, our closest human relatives experienced a "population bottleneck" that decimated their genetic diversity.

A population bottleneck occurs when there is a sudden reduction in genetic variation within a species. Bottlenecks in a species can be brought on by a number of processes, such as climate change, hunting or genocide. The end result of a bottleneck may be a population that is sickly or on the verge of extinction.

The scientists identified the bottleneck by analyzing changes in the shape of the Neanderthal inner ear over time.

When they analyzed the inner ears of Neanderthal skulls, they discovered that there was an abrupt decline in variation in this bone in skulls dated to the beginning of the Late Pleistocene, signaling a significant change in the Neanderthal skeleton.

Typically, comparisons among ancient DNA samples help researchers pinpoint when bottlenecks happened. But in this case, the team used the reduced variation in the Neanderthals' ear bones as a proxy. They focused on the semicircular canals, a set of bony tubes in the inner ear that are fully formed at birth. During life, these canals are filled with fluid, helping to maintain balance and detect head movements, such as shaking or nodding. Because semicircular canals are evolutionarily "neutral" — because their variation does not affect a person's survival — tracking subtle changes in the canals over time can shed light on the size and diversity of a past population.

Related: Did we kill the Neanderthals? New research may finally answer an age-old question.

Using CT scans, the researchers examined the semicircular canals of 30 Neanderthals from three time periods: 13 from the site of Sima de los Huesos in Spain that were dated to 430,000 years ago, 10 from the site of Krapina in Croatia that were dated to 120,000 years ago, and seven "late" Neanderthals from France, Belgium and Israel that were dated to 64,000 to 40,000 years ago.

This analysis revealed that the group of late Neanderthals had significantly lower variation in their inner ear bones than the earlier groups did, which led the researchers to conclude that a genetic bottleneck event occurred more recently than 120,000 years ago.

"By including fossils from a wide geographical and temporal range, we were able to capture a comprehensive picture of Neanderthal evolution," study co-author Mercedes Conde-Valverde, a biological anthropologist at the University of Alcalá in Spain, said in a statement. The reduction in diversity between early and late Neanderthals "is especially striking and clear, providing strong evidence of a bottleneck event," she said.

The findings fit in well with previous discoveries about Neanderthals, such as evidence of population turnover that negatively affected European Neanderthals' numbers. But it is unclear if the same pattern holds for southwestern Asian Neanderthals, like those who lived at Shanidar in Iraqi Kurdistan, the researchers wrote in their study, since their skulls were not available for analysis.

Neanderthal quiz: How much do you know about our closest relatives?