Monkeys use some of the same basic mental strategies as people do to perceive abstract relationships between shapes, a new study suggests.

The findings challenge the idea that humans crossed a sharp evolutionary divide when they learned to recognize geometric properties like symmetry, parallel lines and right angles, the researchers say.

"While humans do come up with geometric descriptions that are more abstract than what nonhumans can do, there's still some overlap, some similarity in the kinds of geometric intuitions you see in humans and those of non-primates," study co-author Jessica Cantlon, a professor of developmental neuroscience and psychology at Carnegie Mellon University, told Live Science. "So there's a thread of continuity that runs through geometric reasoning between humans and nonhumans."

The research, published July 20 in the journal PNAS, adds to a long-standing scientific debate over whether humans possess entirely unique forms of abstract thought or unusually sophisticated versions of abilities found elsewhere in the animal kingdom.

"For decades, cognitive scientists have searched for the 'special ingredient' that distinguishes human intelligence from that of other animals," Elizabeth Brannon, a professor of psychology at the University of Pennsylvania who was not involved in the research, told Live Science in an email. "This study provides compelling evidence that, at least for geometric reasoning, the difference between humans and other primates is more quantitative than qualitative."

In other words, the study suggested that baboons and macaques don't lack the ability to reason about geometry. Instead, they just aren't as proficient at it as humans, meaning that humans didn't evolve a new unique skill in understanding geometry.

A geometric matching game

The researchers tested eight adult monkeys: four rhesus macaques (Macaca mulatta) and four olive baboons (Papio anubis). The olive baboons participated through the Primate Portal, a touch-screen system installed at Seneca Park Zoo in Rochester, New York. One baboon, Kalamata, was especially enthusiastic.

"Every day he came to the touch screen," Jialin Li, a doctoral student at Carnegie Mellon University and first author of the study, told Live Science. "He just sat there and worked for two hours, three hours straight, completing thousands of trials. That's just amazing."

The macaques participated separately at Carnegie Mellon University, having prior experience with matching tests in other experiments.

The researchers then compared the animals' performance with that of 58 U.S. preschoolers ages 3 to 6, and 79 adults from the Tsimané, an Indigenous farmer-forager society in Bolivia whose members received little formal education. A separate experiment in the larger project involving rotating shapes also included 21 U.S. adults.

In all of the study's cohorts, the participants played a game known as a match-to-sample task.

"[The participants] see a sample shape first," Li said. "For example, it's a square. Then they need to tap the square to make sure that they are looking at it. When they tap it, there will be two shape choices that come up: one on the left and one on the right. They need to choose which shape matches with the sample shape."

The researchers made the choice shapes half the area of the sample shape, thus preventing the participants from solving the task by simply matching overall size or pixel count. In another version of the test, they rotated the choice shapes, thereby forcing the participants to identify the underlying form despite its changed orientation.

Correct answers earned the monkeys fruit-flavored cereal pellets, preschoolers collected stickers that could later be exchanged for prizes, and adults received verbal feedback. Incorrect answers triggered a "bonk" sound and a short timeout from the game.

Despite their limited formal education, the adult group had little trouble with the game, but the monkeys and the children had to put considerable thought into their choices.

"We often think that this matching task will be super easy for humans," Li said. "But actually, young kids were struggling in completing the task in telling the shapes apart, which makes them more similar to monkeys."

Ultimately, the children and monkeys could find the matches, Cantlon said, but only after taking a long time to think about the problem.

The researchers then used computer models to investigate which visual properties best predicted participants' decisions. One model represented simple details, such as edges and lines. Another represented more complex information about a shape's overall form. A third encoded discrete geometric properties, such as equal sides, equal angles, symmetry and parallelism — an approach the researchers described as "symbolic."

According to Cantlon and Li, the term "symbolic" does not mean the monkeys were mentally applying rules such as "a square has four equal sides." Much of the apparent symbolic effect could be explained by the ability to recognize a shape regardless of its orientation, known as rotation invariance.

If abstract geometry depended on a uniquely human symbolic system, only the human participants would have shown evidence of using that thought process. Instead, both monkeys and humans appeared to rely on a mixture of complex visual information and symbolic-like features. Adult humans generally performed the best, followed by preschoolers and monkeys, but their results overlapped. This finding suggests that the differences were quantitative, meaning humans are simply better at the same underlying kind of geometric reasoning rather than possessing an entirely unique ability., Monkeys relied roughly three times more strongly on the symbolic model when the shapes were rotated than when they remained upright.

Brandon said one of the study's most intriguing findings is that what looks like uniquely human symbolic reasoning for understanding geometry may actually grow out of flexible, abstract ways of representing information that are shared by humans and other primates.

Ancient roots of geometry

The results do not mean that monkeys understand formal mathematics, Brannon cautioned. "Human mathematical reasoning extends far beyond recognizing geometric regularities — it includes language, formal proof, recursive reasoning and cultural transmission."

Rather, this study provides evidence that some of the building blocks of mathematical thought have deeper evolutionary roots than previously recognized, she said.

Giorgio Vallortigara, a professor of neuroscience at the University of Trento in Italy who was not involved in the study, agrees with Brannon and her colleagues' conclusions.

Vallortigara explained in an email to Live Science that previous studies have often focused on how animals understand the geometry of their surroundings, such as navigating spaces. What makes these findings different is that they show animals can also reason about the geometric properties of individual objects.

Comparing species can help scientists trace the origins of geometry before language or arbitrary symbols became involved, Vallortigara said. It may also reveal whether similar abilities depend on mechanisms inherited from a common ancestor or evolved independently in animals with different nervous systems.

Li and Cantlon are now breaking down shapes into components such as angles, side lengths and numbers of sides to identify which properties are the hardest for monkeys and humans to understand. Cantlon described the follow-up as "a deconstructed geometry task."

The research could also help educators understand the geometric intuitions children bring into the classroom, Cantlon said, allowing lessons to build upon those abilities rather than treating geometry as something learned entirely from scratch.

"Evolution rarely invents entirely new mechanisms from scratch," Brannon said. "More often, it refines, recombines and extends existing ones."

What do you know about chimpanzees and great apes? Test your smarts with our primate quiz!

A team of UCLA scientists has resorted to posting content on OnlyFans to raise money for research amid huge federal funding cuts to U.S. science. But the videos aren't of themselves, they're exclusive recordings of marmots.

"I spend a lot of time waiting for marmots to do things and had the idea one slow morning," Daniel Blumstein, a professor of ecology and evolutionary biology at UCLA, who leads the project, told Live Science in an email. "When I came back with this idea, one of my graduate students immediately said we MUST do this! So here we are!"

Researchers at the Rocky Mountain Biological Laboratory (RMBL) have been studying yellow-bellied marmots (Marmota flaviventer) at a field station in the Rocky Mountains near Crested Butte, Colorado, since 1962. "The RMBL marmot study is the second oldest continuous study of individually marked mammals in the world," Blumstein said. "We have up to 65 years of data on population dynamics, social and anti-predator behavior and ask a lot of questions about how animals respond to a changing environment."

Yellow-bellied marmots are one of 15 marmot species, a group of cat-size ground squirrels that can be found throughout the Northern Hemisphere. This particular species is widely distributed throughout the Rocky Mountains and several mountain ranges in California. The species live in social groups and are active during the day, which makes them a great subject for long-term behavioral studies.

"Long-term research like ours is both very valuable to understand how and why things change over time, and our project has been very productive," Blumstein said.

However, collecting data over such long periods comes with a significant price tag. And with federal funding cuts draining research budgets across the country, Blumstein and his team have had to look for other methods to raise money for their research. Enter OnlyMarms.

On June 17, the RMBL Marmot Project announced on Instagram that "the state of funding is so bad we are turning to OnlyFans, or as we like to call it 'OnlyMarms'."

OnlyFans is a subscription platform that allows users to pay creators to see exclusive photos and videos. The platform has become popular with adult-only content creators, but it hosts others too, including musicians, athletes and celebrities — and now marmots.

"We’re trying this out of frustration with an extremely challenging funding environment," Blumstein said. "If we’re lucky, it can help raise money for supplies and some expenses. But unless we are very lucky, it won’t replace the federal funding that has driven discovery in the US since the 1950s."

However, for anyone hoping for spicy marmot content, you might be a bit disappointed. "[It's] almost all G-rated content of marmots playing, being cute, digging, bringing plants to their burrows…normal routine stuff for marmots," Blumstein said. "The occasional scuffle makes it PG rated."

Emily Renkey, who also works on the project, said the team hopes to add videos of marmot pups soon.

"Our 'Onlymarms' page has gotten a bit of engagement since we started it a bit over a month back," Renkey told Live Science. "We've gotten 735 page visits and have 44 fans."

But how much has OnlyMarms actually been able to raise? "Not much," Blumstein said. "We’re letting folks have free subscriptions and ask for tips. They [OnlyFans] take 20% and I have to pay taxes on the balance."

Even so, the team is hopeful that the page is helping to increase public engagement and interest in the project. "Overall I think this can be an amazing way to teach people more about animal social behavior, which can sometimes be hard to observe," Renkey said. "Even we are learning more about marmots through these up close glimpses the game cameras provide."

While it is difficult to get signed consent from the marmots to use this content online, Blumstein said that the funds raised would be used to help protect the creatures in a rapidly changing world. "We are using these funds to help continue the study which provides valuable information about them and how they’re responding to climate change," he said.

The OnlyFans account is just one way the team has tried to share its research with new audiences. "We work hard to translate our research findings to the public," Blumstein said. "Our lab’s running a Fat Marmot Week contest this summer. We're hoping this will let people learn more about these fascinating alpine critters!"

Scientists have discovered how mice survive at extreme altitudes on the tips of icy dormant volcanoes in the Andes.

The area where the mice call home extends more than 1 mile (1.6 kilometers) above the world's highest human settlement. The air is thin, temperatures are blisteringly cold, and a desert ecosystem ensures water and vegetation are extremely scarce.

"As a mountain climber standing on the summit of these peaks, the idea that there could be animals living in these barren godforsaken environments is just really mind-boggling," Jay Storz, a professor of biological sciences at the University of Nebraska–Lincoln, told Live Science.

In 2020, Storz led a team of mountaineering scientists who recorded Andean leaf-eared mice (Phyllotis vaccarum) at a record-breaking altitude of 22,110 feet (6,739 meters). The mice were living on the summit of Llullaillaco, the world's highest historically active — now dormant — volcano, located on the border between Argentina and Chile.

Now, in a new study published July 9 in the journal Science, Storz and his colleagues have revealed the biological mechanisms behind the mice's extreme survival. It turns out that the species has evolved a variety of adaptations to survive at such high altitudes, including the ability to eat plants that would normally be toxic.

Before the discovery of the high-altitude mice, researchers had assumed that mammals could only survive up to around 18,000 feet (5,500 m) above sea level. But these hardy animals smashed that record, while also thriving at lower altitudes.

"One of the really notable things about this particular species is that it has such a broad elevational range, from sea level along the desert coastline of northern Chile, all the way up to the summits of some of the highest peaks in the Andes," Storz said.

To better understand these remarkable mice, the researchers studied members of the species at low, middle and high altitudes between 2020 and 2023. The work mixed mountain climbing and animal surveying techniques, with Storz and his team ascending the mountains and setting traps to catch and record the mice.

Storz said that a well-acclimatized mountain climber can tolerate these high elevations for a very short period, but that the conditions are "not remotely compatible with long-term human survival."

The expeditions can be dangerous even for experienced climbers: one of Storz's colleagues was evacuated during a separate expedition in Peru after they developed high-altitude pulmonary edema — a life-threatening form of altitude sickness that causes fluid to build up in a climber's lungs.

The researchers sent some of their specimens to labs in Chile for further analysis. This included putting the mice into small chambers and measuring how they adapted to extreme cold and oxygen deprivation. The team also sequenced the Andean leaf-eared mouse genome, which revealed a variety of local adaptations to different altitudes. For example, the mice living at high elevations were better at maintaining their body heat and oxygen levels than those taken from lower altitudes, according to a statement released by the University of Nebraska-Lincoln.

Another change in the high-altitude mice's genes enabled them to digest food and detoxify plants that would otherwise be harmful to them, according to a statement released by McMaster University in Canada. This special adaptation helps the mice get enough food on the sparsely vegetated volcanoes.

The researchers also revealed that the high-altitude mice were much more active in the daytime, perhaps due to a lack of predators and warmer temperatures during those hours. However, despite local adaptations, the mice were still extremely similar genetically across their elevation range. All of the mouse populations overlapped, which prevented high-altitude individuals from becoming isolated or especially distinct from their low-altitude kin.

Not all of the mice survived the researchers' study. To fully understand the biology of the mice, researchers needed to euthanize them and study their tissues. They also wanted to preserve "voucher" specimens to act as permanent representatives of the species in museums, which researchers can keep returning to for further study. According to the study, the team collected 167 of these voucher specimens.

Storz noted that it's very valuable to have a biological record of specimens archived in museum collections for future generations. He added that their work was not having any impact on the viability of the mice populations, and that the animals were killed humanely, although he did not disclose any details.

"King of the mountains"

Study co-author Graham Scott, a professor of biology at McMaster University in Canada, said that the take-home message of the new research was how life can overcome such extreme environments, and not just survive but thrive. In this case, the mice did this by developing solutions for the cold, oxygen deprivation and food scarcity.

"It just shows the complex ways that evolution has made these animals the king of the mountains," Scott said.

Enduring harsh conditions high in the Andes likely comes with some benefits. Scott said that competition is probably the biggest reason for the mice living at such high elevations. The mice are also pretty much left to their own devices, and thus likely have less to fear from predators.

But this begs the question: Are there any animals living higher than the mice?

"Birds are always a bit hard to nail down because, of course, they can fly and there's certainly records of birds flying at higher elevations than that," Scott said. "But we think this is probably the highest-dwelling animal."

Scientists have identified a new species of monkey that has orange lips and makes unique roars and snorting sounds. The distinctive monkey lives in a remote region of the Democratic Republic of the Congo (DRC).

It is only the fifth new monkey species to be identified in Africa in the past 75 years, and there might be more unknown monkey species in the region, scientists behind a new study suggested. Researchers named the newly identified species of monkey Colobus congoensis, after the region, and it is known by the common name "lik­weli" in the local Kilanga language.

"This is remarkable because it's not very common these days to find a new, never-before-documented primate species, let alone a relatively large species of monkey," said Joshua Linder, an anthropologist and president and co-founder of the The Forest Collective, a nonprofit that aims to conserve and restore tropical rainforests.

In 2008, conservationists in the dense rainforests of Lomami National Park, within the Congo Basin in the DRC, photographed an unidentified monkey, but it was partially obscured. Then, in 2018 a similar-looking animal was captured on camera, prompting study co-author Junior Amboko, a Lomami National Park researcher and a Florida Atlantic University anthropologist, to set out to find the mysterious monkey.

To see what was already known, Amboko and his colleagues showed the pictures to people from 52 villages around the park.

"These people really know the fauna and flora in the forest," Amboko told Live Science. "In only eight villages, people knew the monkey ‪—‬ and these were hunters, who know the economic value of animals or how much food each animal can provide, but even they didn't know much."

Hunters of the Balanga ethnic group called the monkey "likweli," although the meaning of this name isn't known. Some in the Mituku local communities called the species "kasaba nkoni," which Amboko said means "the branch shaker." This refers to the way colobus monkeys leap from branch to branch, Amboko said.

In their searches between 2018 and 2022, the researchers recorded 114 sightings of the species across an estimated range of about 660 square miles (1,700 square kilometers) naturally isolated between the Lomami and Lualaba rivers. They reported their findings July 15 in the journal PLOS One.

The monkeys, seen hanging out in groups of between one and 20 individuals, are mainly glossy black, but they have a conspicuous orange patch around the mouth and nose. Bare gray skin on their cheekbones makes it look as if they're wearing masks. They also have a patch of white fur around the anus.

"We're going with the face and the rump as the two distinctive traits," said study co-author Kate Detwiler, an anthropologist at Florida Atlantic University. "If you see the face, you see this unique bare skin that's orange cream. And then if you're coming from behind, you see this white patch."

The monkeys, which weigh about 15 pounds (7 kilograms), also make deep, loud roars, punctuated by distinctive snorts. These unique‬ vocalizations distinguish them from other colobus monkeys, Detwiler told Live Science.

By taking samples, and sequencing DNA, from monkeys killed by hunters and destined for the illegal bushmeat trade, and comparing the results with what’s in museum collections and datasets of genetics, skulls, teeth and pelts for other colobus monkeys, the team confirmed that C. congoensis was a previously unknown species.

"My lab got the tissue sample and did the genetics, and we were shocked by how divergent the key area of the mitochondrial genome was from other colobus monkeys," Detwiler said.

The monkeys live in the same forest as the Angola colobus (Colobus angolensis), but their closest relatives are black colobus monkeys (Colobus satanas), which live around 750 miles (1,200 kilometers) to the west, in Cameroon, Gabon and Bioko Island.

"The fact that the results show that the closest living relative to this new species is the black colobus located 1200 km away in West Africa is equally remarkable," Linder, who was not involved in the new study, told Live Science via email.

Detwiler estimates that these close relatives diverged between 5.78 million and 3.44 million years ago ‪—‬ the longest known split between species within the Colobus genus. "The discovery is reshaping our understanding of African monkey evolution," she said.

Given the small geographic range, rare sightings and increasing habitat loss, the researchers recommend that C. congoensis be classified as endangered on the IUCN Red List.

The discovery also emphasizes the importance of Lomami National Park, where another previously undescribed monkey, the lesula (Cercopithecus lomamiensis), was reported in 2012 by a team that included Detwiler.

The Congolian rainforest ranging across this part of Africa is the world's second-largest tropical forest, after the Amazon, and about 60% of it is in the DRC. "It is a paradise for biodiversity," Amboko said, adding that there might be more undescribed primate species there. "If we are able to discover two big new primate species, who knows how many other new mammals, fish, reptiles or plants there could be?"

What do you know about chimpanzees and great apes? Test your smarts with our primate quiz!

Scientists in Australia are deep-freezing koala eggs and sperm as a "genetic backup" to save the wild population from future extinction.

The backup could be used to create healthy koala embryos through artificial insemination and in vitro fertilization (IVF), the researchers said in a statement. When koalas (Phascolarctos cinereus) die, unique traits and diverse genes that may help them adapt to changing environments are lost, but the new project offers a way to store this valuable material, the team said.

"Losing genetic diversity can weaken future generations and decreases the ability of the species to adapt to challenges," Andres Gambini, a reproductive biologist at the University of Queensland who is involved in the project, said in the statement. "This project will create a safe and systematic way to rescue and preserve koala spermatozoa and eggs to support future conservation programs."

Australia is facing a paradox with its koalas. In some regions of Queensland and New South Wales, koala populations have crashed by as much as 80% since the late 1990s due to deforestation, bushfires, drought and disease. This prompted the Australian government to change koalas' conservation status in their eastern range from "vulnerable" to "endangered" in 2022.

Meanwhile, in parts of southern Australia, koalas are overabundant. However, the places where koalas are currently thriving may not be able to support a booming population much longer, because the animals are overbrowsing and killing the trees they need to survive, recent research suggests.

To protect against koalas' decline, the scientists will freeze koala reproductive cells in liquid nitrogen (LN2), which has a boiling point of minus 321 degrees Fahrenheit (minus 196 degrees Celsius). This method would enable the team to cryopreserve the cells for several decades until they are needed, said Vincent Lynch, an evolutionary developmental biologist and associate professor of biological sciences at the University at Buffalo in New York.

"I've successfully woken cells up that were frozen in LN2 a couple of decades ago," Lynch, who is not involved in the koala project, told Live Science in an email.

The sperm and eggs will be supplied by wildlife hospitals that will harvest sex cells from dead koalas or koalas that can no longer breed due to disease or trauma, according to the statement.

"Every year, many koalas are admitted to wildlife hospitals because of illness or injury and sadly, not all of them survive," Gambini said.

The researchers will then test the cells for Chlamydia pecorum, a highly contagious and deadly form of chlamydia. In koalas, this infection causes painful urinary tract infections, gastrointestinal issues, and conjunctivitis, which can lead to blindness. It can also cause infertility in females. C. pecorum is one of the main contributors to koalas' decline in recent years, with infertility driving a sharp reduction in the number of koala joeys being born. In the worst-affected populations, situated mostly in Queensland and New South Wales, almost 90% of koalas are infected with chlamydia.

If the reproductive cells contain C. pecorum, "we have the technology now to remove the infection from the samples," Steve Johnston, an associate professor of animal reproduction and captive husbandry at the University of Queensland who works on the koala project, said in the statement.

In 1998, Johnston was part of a research team at the University of Queensland that created the world's first koala joey born through artificial insemination. The new project also builds on a 2025 study, led by Gambini, that produced the first-ever IVF kangaroo embryos. (These did not result in live births; at the time, the scientists said that would take another decade.)

It's unclear how many sperm and egg cells the researchers plan on freezing, and it's hard to say how many cells they would need to ensure the survival of healthy koala populations, as the number of cells required is probably increasing with time, Lynch said. As koala populations shrink, genetic material is being lost at an accelerating pace, so the team will have to get more samples as time goes on to obtain the same amount of diversity.

The project does not replace more traditional conservation approaches — such as habitat protection, disease management and population monitoring — but researchers cannot afford to wait until populations are smaller and genetic diversity is harder to recover, Gambini said.

Although conservationists are concerned about the fast rate of koalas' decline, "there is a chance" that scientists can save the species through cryopreservation, Lynch said.

"I support multipronged approaches like this," he said. "By preserving the environment with traditional conservation we allow re-introductions because the species have somewhere to live."

Pets form an important part of many people's lives, providing meaningful companionship. However, our pets can sometimes also be a source of unwelcome pathogens and diseases, particularly if they frequently roam outdoors.

We are ecologists and a veterinarian who study wildlife health and the movement of pathogens among wildlife, domestic animals and people. If you let your cat outdoors, or if outdoor cats visit your yard, our recent findings may be relevant.

Zoonotic pathogens are organisms that can infect both animals and humans. From a pathogen's perspective, humans are just another animal host. Wildlife is often emphasized as a source of emerging disease for humans because there are vastly more wild animal species than domestic animal species.

However, even if a pathogen is capable of infecting people, it needs a way to reach us. Humans share more zoonotic pathogens with domestic animals than with wildlife, because domestic animals live close to us. Pathogens benefit even further if they can infect a companion animal.

In our newly published research, we compiled data from more than 400 studies to investigate how a cat's lifestyle, whether they're mostly indoors, outdoor-roaming or feral, affects that cat's likelihood of carrying pathogens that can infect people.

Across this compilation, there were nearly 100 pathogens detected in cats that are considered zoonotic and capable of infecting humans. Familiar examples are rabies, Toxoplasma gondii, roundworms and Salmonella.

Our research

We found that outdoor-roaming pet cats had three to five times the odds of carrying a zoonotic pathogen compared with indoor-only cats. More surprisingly, cats allowed to roam outdoors had similar odds of carrying at least one zoonotic pathogen as feral cats. Outdoor-owned cats carried fewer types of pathogens than feral cats, but the same pathogens that infect feral cats can also infect owned cats.

These risks become a large-scale problem because pet cats that roam freely interact closely with people, wildlife and other domestic animals. Across the studies we reviewed, about 60 per cent of owned cats had unsupervised outdoor access; in some regions, that rate exceeded 90 per cent.

Roaming cats hunt, interact with wildlife or other domestic animals, and move through environments contaminated with pathogens and toxins. Research suggests that cat owners may underestimate hunting by around 80 per cent, meaning that many prey captures and animal contacts go unnoticed.

These interactions are not uncommon and not limited to so-called pest species. Single-country estimates of wildlife killed by cats run into the billions, with more than 2,000 wildlife species documented as prey for domestic cats.

Cats hunt animals that can carry zoonotic pathogens, including rodents, birds and bats, many of which would otherwise have little direct contact with people. Owned cats might bring home rodents carrying viruses, and there are documented cases of cats bringing rabies-positive bats into homes. A cat returning home with prey can therefore create a pathway by which pathogens circulating in wildlife populations reach people.

In addition, it is not only owners who are at risk. Outdoor cats defecate in gardens, parks, playgrounds and other shared spaces, potentially leading to high contamination rates. One study estimated that outdoor cats deposited more than 60 tonnes [60 tons] of feces per 10,000 households each year.

Depending on the parasite, feces can contain hundreds to hundreds of thousands of parasite eggs that can persist in soil or water for months to years, which can infect people or other animals that come in contact with those eggs.

What cat owners can do

The most straightforward intervention is also the most economical and humane: prevent unsupervised roaming. That does not mean denying cats access to the outdoors. It can mean building "catios" or enclosures, leash walks, supervised time outside or other forms of contained outdoor access.

Veterinary care still matters. Treating existing parasitic infections and vaccinating against diseases like rabies are essential precautions, even for indoor cats. Since neither vaccines nor anti-parasitic treatment cover the full spectrum of wildlife-associated pathogens, managing exposure remains the more comprehensive protective approach.

The free-roaming debate is often framed as a false choice: either cats roam freely, or they are deprived of a natural life. That framing is misleading and inconsistent with how we manage other companion animals.

We do not assume dogs need unrestricted access to roads, neighbors' yards or to hunt wildlife to have good welfare. Indoor cats and cats with supervised outdoor access can live healthy, enriched and longer lives.

Policies and strategies that address how and where owned cats roam outdoors can help safeguard biodiversity, feline and wildlife welfare and public health. That is the central insight of One Health, that the same choices that protect ecosystems can also protect the animals and people who share them.

This article was co-authored by David Lapen, who works for and receives research funding from Agriculture and Agri-Food Canada.

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

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A camera trap in an ancient Polish forest has captured extremely rare and unexpected footage of wolves attacking a bison herd made up of adults, youngsters and a newborn calf, a new study shows.

The event took place on Sept. 15, 2025. Five wolves (Canis lupus) enter the camera frame, closely followed by three bison cows and the newborn calf. In the footage, the cows chase after the wolves, leaving the calf alone and exposed. The wolves then surround the calf, bite its neck and try to drag it away, but two cows come to its rescue. The wolves return and seize the calf a second time in the background of the video — however, this time the entire bison herd comes to its defense to end the attack.

The clip is from the Bialowieza Primeval Forest, the oldest and best-preserved temperate lowland forest in Europe, which hosts the world's biggest population of European bison (Bison bonasus). The forest covers 350,600 acres (141,900 hectares) on the border between Poland and Belarus. There are more than 870 bison on the Polish side, according to the new study, while the Belarussian side has roughly 730 bison.

Also known as "the king of the forest," the European bison is typically considered a non-prey species, meaning it has no predators except humans. But the footage calls this into question.

"To our knowledge, we present the first video-recorded evidence of wolves attacking a European bison herd in the Białowieża Primaeval Forest," researchers wrote in the study, published May 29 in the journal Ecology and Evolution. "Although the video did not capture a direct kill, it suggests that other attacks on European bison could potentially be successful."

Historical documents show that wolf attacks on European bison used to be more common, with about 8 kills recorded annually in the Bialowieza Primeval Forest between 1840 and 1849. The forest was a popular hunting ground for monarchs from the 14th century onward, explaining why such detailed records exist.

European bison went extinct in the wild in 1919, but they were reintroduced in the Bialowieza Primeval Forest in 1952. The first confirmed bison kill since then dates to the mid 1990s, and after that, it seems as though wolves stuck to a diet of roe deer (Capreolus capreolus), red deer (Cervus elaphus) and wild boar (Sus scrofa), likely because these are much easier prey than bison, the researchers wrote in the study.

But now, "our observation demonstrated that the European bison is in fact a potential prey for wolves," they wrote. "This raises questions about why predation attempts are so rare, whether the bison can still be described as a non-prey species, and what this could mean for conservation and management of the species."

An intriguing trend in the Bialowieza Primeval Forest is that wolf packs are growing in size, possibly thanks to a late 1980s hunting ban. This shift could increase wolf predation on bison in the future, because bigger packs can handle bigger prey.

"If predation on European bison, specifically young animals, occurs more frequently than previously assumed, wolves could play a small but potentially important role in the natural regulation of bison numbers," the researchers wrote in the study. "In turn, such regulation could possibly lead to mitigation of human-bison conflicts."

An elusive dwarf fox that was feared extinct has been photographed for the first time, after being spotted near a highway in Cozumel, Mexico.

The tiny animal was part of the mysterious Cozumel fox population, a potentially undescribed species that had not been officially sighted in more than 20 years.

Cozumel foxes live only on Cozumel, an island near Cancún. Researchers know very little about these mysterious predators, which are roughly 20% to 40% smaller than their gray fox (Urocyon cinereoargenteus) cousins that live on the mainland.

Park and museum officials spotted and captured the fox in 2023 and, after a health assessment, released it back into the wild. Researchers have now shared the photographs and documented the encounter in a new study published May 4 in the journal Neotropical Biology and Conservation.

Although the rediscovery confirms that Cozumel foxes are still alive, they are likely on the brink of extinction, the study authors noted; the photographs highlight the need for focused research and conservation efforts.

"The biggest challenge facing the Cozumel fox is that we still know almost nothing about it, including its remaining population size, distribution, or ecology," study first author Travis Bayer, executive director of the conservation organization Pathos Wildlife, said in a statement. "That uncertainty alone is dangerous, because it makes effective conservation extremely difficult."

Cozumel foxes are an example of insular dwarfism, an evolutionary process in which larger animals, including fox-sized mammals, evolve to be smaller after colonizing islands, where there are limited resources and less space than on the mainland. The foxes aren't the only mammals that have shrunk on Cozumel over time; other examples include the island's critically endangered pygmy raccoons (Procyon pygmaeus) and dwarf coatis.

Archaeological evidence suggests that Cozumel foxes have lived on the island for at least 5,000 years, likely since before the arrival of the Maya within the past few millennia, and potentially for tens of thousands of years before that. Prior to this rediscovery, the last confirmed sighting of a Cozumel fox was in 2001, according to the study.

The rediscovery began with reports of a disoriented animal wandering near the highway on the southeastern side of the island. Officials with the Parks and Museums Foundation of Cozumel located and captured the fox, an adult male, on Sep. 14, 2023. They checked its health and later released the fox in the Laguna Colombia State Reserve, a protected area just south of where it was captured.

Recent and historical sightings suggest that Cozumel foxes could have an extremely restricted range in the island's South, where nature is increasingly threatened by development, land-use change, invasive species and natural disasters, the study authors noted.

The researchers recommended surveys to determine the current distribution and size of the Cozumel fox population, along with morphological and genetic assessments to establish its evolutionary status and conservation efforts to protect its assumed habitat in southern Cozumel and minimize human-wildlife conflict.

"Ultimately, we hope this work helps move the Cozumel fox from a little-known, uncertain presence on the island to a better-understood key part of Cozumel's ecosystems," Bayer said. "We also hope it demonstrates that conservation is often most urgent when certainty is lowest and that uncertainty itself can be a call to action."

A single climate-change-fueled cyclone killed 7% of Tapanuli orangutans ‪—‬ the world's rarest great apes ‪—‬ in just four days last year, new research reveals.

The study shows that "climate change-driven weather poses an immediate, catastrophic threat to the world's rarest great ape," the researchers wrote.

Tapanuli orangutans (Pongo tapanuliensis) live in the Batang Toru forest in northern Sumatra, Indonesia. Pushed to the brink of extinction by habitat destruction, the entire species consisted of 767 individuals in 2019, of which 581 lived in the forest's west block.

Then, Cyclone Senyar arrived.

Across four days in November 2025, the rare and damaging tropical cyclone caused extreme rainfall and catastrophic landslides across this west block forest region, killing approximately 58 Tapanuli orangutans. These individuals died from drowning, suffocation under landslides, or impacts from collapsing trees, according to the study, which was published June 10 in the journal Current Biology.

The loss equates to 11% of the west block orangutans and roughly 7% of the whole species.

"It is extremely worrying for the future of this ape," study co-author Serge Wich, a professor of primate biology at Liverpool John Moores University in the U.K., told The Guardian.

World's rarest great apes

Tapanuli orangutans were classified as a new species, distinct from their Bornean (P. pygmaeus) and Sumatran (P. abelii) orangutan cousins, in 2017, making them the most recently identified, and rarest, species of great ape.

Orangutans are especially vulnerable to environmental shocks because of their slow rate of reproduction; they have roughly six- to nine-year gaps between each baby. They are also heavily dependent on tree cover to survive.

In the new analysis, researchers combined pre- and post-cyclone satellite imagery with orangutan population density estimates to evaluate the impact of the flooding and landslides on the apes.

Before the cyclone, 99.3% of the Batang Toru forest west block was forested. Then, after the storm's arrival, 21.8 inches (556 millimeters) of rain fell over four days, leading to landslides across 20,517 acres (8,303 hectares) of Tapanuli orangutan habitat. The researchers identified over 50,000 "scars" from this landslide-induced habitat destruction in the forest landscape.

This habitat loss was catastrophic for the orangutans. "Given the high density (>50,000) of sudden, steppe-slope landslides causing canopy collapse and debris flow into drainage networks, and the limited opportunity for arboreal [via trees] escape during rapid slope failure, we consider mortalities by burial, trauma, or subsequent drowning to be likely," the authors wrote in the study.

The long-term effects of topsoil destruction on the food supply will also harm the remaining orangutans, the authors wrote. With topsoil containing dense networks of plant-feeding fungi, it will take time for the fruit and leaves the orangutans rely on to return.

World Weather Attribution, a research group that studies extreme weather events, found that Cyclone Senyar was intensified by a combination of human-induced climate change, an ocean oscillation called the negative Indian Ocean Dipole, and La Niña, the cooler phase of the El Niño-Southern Oscillation climate cycle.

Climate change is projected to increase the frequency and intensity of heavy rainfall worldwide, including in Indonesia. And now that El Niño is officially here, the climate event will likely make the Pacific hurricane season stronger. This El Niño period is forecast to "rank among the largest El Niño events in the historical record going back to 1950," NOAA officials wrote in a June 11 update.

"El Niño conditions will pour fuel on the fire of a warming world," U.N. Secretary-General António Guterres said in a June 2 video statement. "The world must treat it as the urgent climate warning it is."

Polar bears are intensely curious animals. That curiosity often brings them into contact with people and can put both species at risk from one another.

As the Arctic climate warms, some polar bears are spending more time on shore, away from the sea ice habitats they rely on to hunt seals. As the bears are under nutritional stress due to ice loss, some wonder if they're being forced to take more risks around people as they seek food, increasing interactions and conflicts between polar bears and people. But until now, there're been little research into this relationship.

Between 2011 and 2021, research colleagues and I placed trail cameras at three camps in Wapusk National Park in Manitoba and, later, at the nearby Churchill Northern Studies Centre (CNSC) to see how often polar bears visited these sites on the west coast of Hudson Bay.

The project began at the invitation of Parks Canada when their newly constructed field camps at Broad River and Owl River turned out to receive more bear visits than they expected. Those camps had been located away from the coast to reduce the likelihood of polar bear encounters, so answering this immediate question was a priority.

We investigated whether human activity, the length of the ice-free season — or both — were influencing polar bear visits. In approximately 80% of the bear visits, our photos showed enough of the animal that we could rate their body condition using an established fatness index.

We observed 580 bear visits with our cameras, mostly between July and November, when bears are well-known to be abundant in the area. What we found was that human presence at the camps and the CNSC didn't have any effect on the number of bear visits. The length of the ice-free season each year, however, had a notable effect.

It’s all about ice

The ice-free season can be longer if sea ice breaks up earlier in spring than normal, forms later in fall than normal, or both. During our study period, there was no long-term trend in the ice-free season's length, but it did vary a lot year to year. We found that the longer western Hudson Bay remained ice-free in a year, the more frequently bears visited our study sites.

Poor body condition is considered an indicator of nutritional stress, and a healthy body condition to survive on-shore fasting is critical for polar bear survival.

But rather than getting visits from hungrier bears that were detectably thinner — which is what we had expected — we found that the more time bears were off the ice, the more likely all bears were to approach our study sites, regardless of their nutritional health.

This result was unexpected since other research shows underweight polar bears are more likely to attack people, which has been taken to mean that those particular bears would take more chances to find food and so be more likely to approach or prey on people.

Instead, what we're seeing is that body condition may play a different role. Rather than influencing the bears to seek human interactions, body condition might instead influence whether interactions between people and polar bears escalate.

In other words, if polar bears are around people to begin with, a skinny bear might be more likely to aggressively try to obtain human food sources, or even prey on people, than a bear under less nutritional stress.

We were also surprised not to see many lone sub-adult bears in our photos. Those other studies have also shown that they're usually the ones most likely to come into conflict with people.

These observations, though, are consistent with other research on this sub-population. As the ice-free season has on average lengthened in western Hudson Bay, the production and survival of juvenile bears has dropped. Our unexpected results, then, are probably due to there simply not being many young bears in the population during our study.

Scientific and Indigenous observations

Our findings suggest that sea ice loss probably doesn't lead to more interactions with people just because polar bears are thinner or hungrier, so we need to better understand what can cause interactions to worsen into attacks.

What does this mean for current approaches to reducing the risk of polar bear-human conflicts? Bringing it back to the Parks Canada's original question, it appears that the likelihood of bear visits to their camps isn't affected by anything under human control, but the outcomes of any bear visits that do take place certainly are.

What we found may also help explain why scientific explanations and Indigenous and local observations of polar bear-human interactions have differed. Scientific literature has long maintained that poor body condition drives polar bears into northern communities.

However, documented observations from those communities themselves indicate bears who come into communities are not necessarily in poorer condition than would be expected.

Our findings align more closely with Indigenous observations, highlighting how untested assumptions can, through repetition in scientific literature, solidify into accepted wisdom.

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

They sleep on our beds, steal our food, and generally rule the house. Between them, cats and dogs make up two-thirds of pet ownership worldwide. But which of the two companion animals are we more closely related to?

The answer depends on how you look at the question.

"From an evolutionary perspective we are equally related to dogs and cats," Mark Springer, a professor emeritus of evolution, ecology and organismal biology at the University of California, Riverside, told Live Science in an email.

Cats, dogs and humans are all mammals. In the mammalian family tree, which maps out how different mammal species are related to one another, both cats and dogs belong to the order Carnivora, while humans are primates. These two groups split from a common ancestor about 90 million to 95 million years ago, Springer said. Meanwhile, cats and dogs split from each other much later, around 55 million years ago.

In terms of common ancestry, "dogs and cats are more closely related to mammals such as pangolins, horses, cows, whales, bats, shrews and moles than they are to humans," Springer said. And "humans are more closely related to colugos [flying lemurs], tree shrews, rabbits, rats, and mice than they are to cats and dogs."

Genetic ties

Another way of deciding which species we are more closely related to is through a genetic lens.

If you measure how much the DNA code has changed over time, humans are about equally related to cats and dogs, William Murphy, a comparative genomicist at Texas A&M University, told Live Science in an email.

However, scientists also compare how DNA strands are organized within chromosomes. Here, a difference emerges.

Murphy explained that the ancestors of modern-day dogs went through extensive chromosome rearrangements over evolutionary time. (Such rearrangements are not unique to dogs; they occur across different animal and plant species, though scientists don't fully understand why some lineages rearrange faster than others.) Cats, on the other hand, retained a genome organization that's closer to ours. "In terms of how genes are arranged within chromosomes, humans and cats are twice as similar to each other as humans are to dogs," he said.

Because the way DNA is organized affects how genes are switched on and off, cats may be a better model than dogs for understanding human gene regulation, Murphy said.

That also makes them useful for studying genetic diseases. For example, polycystic kidney disease occurs in both humans and cats, and treatments developed for cats could help inform therapies for people.

Cats may also provide clues about cancer. A recent study found that cancer-related genes in cats are strikingly similar to those in humans, both in number and variety. One notable example involves a gene called FBXW7, which was mutated in more than half of the feline mammary tumors studied. In humans, mutations in the same gene are linked to worse outcomes in breast cancer

That said, dogs are also used to model and analyze human illness, including Alzheimer’s disease, idiopathic epilepsy, eye disease and heart disease.

Although cats may share more similarities with humans in gene regulation, to date more research has focused on dogs. This may be due in part to the fact that the complete feline genome became available later than the canine genome, as well as historical bias — cats have long been perceived as less cooperative in research settings.

So, which are we more closely related to? From an evolutionary standpoint, it's a tie, but genetically, at least in terms of genome structure, we are closer to cats.

How much of a cat fan are you? Find out by taking our cat quiz!

Whether it's having the "eye of the tiger" or being lionhearted, references to lions and tigers evoke power and determination. That's not surprising given these animals are both large, powerful felines. But they are distinct species. So what do these iconic cats have in common, and how are they different?

To answer this question, let's consider the two species' appearances, evolutionary histories and how they live their lives as kings of their ecosystems.

Appearance and anatomy

The most obvious difference between modern lions (Panthera leo) and tigers (Panthera tigris) is their distinct physical appearances, particularly their coats.

"Just looking at them, you can clearly tell that tigers have stripes and lions don't," Dell Guglielmo, a zookeeper who cares for lions and tigers at Smithsonian's National Zoo, told Live Science. "The lion males have the large huge mane, and the females do not." In contrast, male and female tigers look the same.

A tiger's stripes help the cat blend in among the patterns of shadows and light created by grasses and trees in the dense temperate and tropical forests of Asia where they live. The orange and brown or black stripes stand out to the human eye, but to a tiger's colorblind prey, orange appears green and blends in. The stripes are pigmented on their skin, too. Each tiger's stripe pattern is unique, Guglielmo said.

Lions' tawny coloring also serves as camouflage. Lions blend in with the dry grasses of Africa's open savannas.

On the inside, however, lions and tigers are very similar. "If you look at the skeletons, all cats essentially look the same," Z. Jack Tseng, an associate professor of integrative biology at the University of California, Berkeley, told Live Science. There's an unofficial saying among those who study cat fossils. If "you ask them to describe the cat family fossil record, usually people will say, 'Well, a cat is a cat is a cat,'" Tseng said. Even your pet cat is basically identical to a lion or tiger, skeletally speaking — just proportionally a lot smaller.

Evolutionary differences

Despite their similarities, "lions and tigers are not each other's closest relatives," Tseng said. Tigers are more closely related to snow leopards, while lions are grouped with leopards and jaguars.

Moreover, tigers emerged much earlier as a species than lions. "The oldest putative tiger fossils are around 2 million years old," Tseng said, "whereas lion fossils are probably no more than a million years old, probably younger than that."

When it comes to classifying cats, size matters. Lions and tigers belong to the Panthera genus, along with leopards, jaguars and snow leopards. The last common ancestor of all five species likely emerged at least 5.57 million years ago, a genetic modeling study found. Tseng and his co-authors modeled this age based on genetic sequences and anatomical data, such as characteristics of bones and teeth. No fossil has been found yet, but this ancestor was likely smaller than lions and tigers, Tseng said.

He noted that both species independently evolved to be large. Animals can grow in body size for a variety of reasons, including living in cooler climates, as this gives them a smaller surface area-to-volume ratio, which helps to reduce heat loss. "The fossil record is not detailed enough to say whether lions and tigers got large independently for the same reasons, but they probably followed one or more of these broader trends as they evolved," Tseng said.

Behavior

Lions and tigers behave quite differently in the wild. Lions live in social, matriarchal groups with multiple female relatives and one or two male adult lions who may leave if challenged by another male. That's where the mane can come in handy.

"Cats often go for the neck when they fight and when they kill their prey," Jacob Shanks, a wildlife care manager at San Diego Zoo Wildlife Alliance, told Live Science. "Male lions being social, there's a lot of battling for territory and access to reproduction and other resources, so the manes help protect against neck wounds."

Tigers have far less social interaction than lions do. Tiger cubs remain with their mother for two years before going their separate ways. As adults, tigers generally avoid each other, aside from breeding. When a tiger wants to approach another individual, it makes a puff-like sound, called a chuff, by pushing air through its nose. Tigers are "one of the only cat species that chuff," Guglielmo said. If the second tiger is OK with the first tiger moving closer, it will chuff back. "Lions don't use a chuff; they just use different body language or just walk up and see if it works," Guglielmo said.

Would tigers and lions ever meet in the wild? That's not likely, as they live in completely different parts of the world. Even in the fossil record, there is no overlap in their range, which prevents the two species from competing and breeding, Tseng said.

However, humans have artificially bred lions and tigers in captivity, creating a hybrid called a liger. "Hybridization doesn't exist in the wild," Shanks said. "I've never seen a case of wild lion-tiger hybridization." Making hybrids doesn't benefit either species, he added.

A key similarity between lions and tigers are the threats they face. Tigers are considered endangered, and lions are vulnerable, according to the International Union for Conservation of Nature. Both big cats face threats from human conflict, habitat loss and climate change. "They need active conservation to protect and to help improve if we're going to not have them slip away," Shanks said.

Think you know about lions and tigers? Test your smarts with our big cat quiz!

Most cat owners are familiar with the funny head shake their pets do, often after eating, drinking or enjoying a nice cheek scratch ​​‪—‬ they flick their head back and forth a mile a minute. Dogs and other mammals are known to show similar behaviors.

So why do our furry friends shake like this, and does it mean something is wrong?

Usually, this head shaking is totally normal, experts told Live Science. However, the reasons for it can vary a bit between cats and dogs.

Why cats shake their heads

Cats shake their heads when the nerve endings on their heads are stimulated, Sarah Crowley, an anthrozoologist at the University of Exeter in England, told Live Science.

"The physiological driver for it is stimulation of the very sensitive hairs and nerve endings around the top of the head, particularly around the ears," she said.

These nerve endings can be stimulated by a satisfying scratch, prompting the kitty to shake it off. "If a caregiver has touched a sensitive area" ‪—‬ for example, around the ears or whiskers — "this may result in a head shake," said Amy Miele, a clinical animal behavior lecturer at The Royal (Dick) School of Veterinary Studies at the University of Edinburgh in Scotland.

This rapid swinging motion is very effective at dislodging obstructions, such as food or drink, from the cat's ears or whiskers. It can also help to resettle their fur, Crowley added.

"Often the head shake is followed by grooming of the face [or] ears," Miele told Live Science in an email.

The rapid head toss can also indicate annoyance. It's often a response to having their ear blown on — not something you should do on purpose, as they don't like it.

Thankfully, this erratic side-to-side motion doesn't usually cause dizziness. "Animals (including humans) are more likely to make themselves dizzy by spinning in circles," Miele said.

The full-body shake

Cats aren't the only animal with these silly shakes. "Lots of mammals have this head shake reflex to something in or around their ears," Crowley said. "You see mice and rats do it when they've been eating and drinking."

In dogs, breeds with upright ears, like German shepherds, are more likely to shake their heads than floppy-eared pups such as King Charles spaniels because it's easier to get something (like a grass seed or insect) stuck in an open ear.

Dog owners might recognize other types of shakes: the predatory shake (when your pooch tries to playfully "kill" its toys by whipping its head from side to side while its "prey" is in its mouth) and the full-body shake, sometimes called the "wet dog shake." "It starts at the head and then rolls down the whole body and ends at the tail," Crowley said. This is the kind of post-bath shake that soaks everything in your bathroom before you've had a chance to dry Fido with a fluffy towel.

The full-body shake can also indicate a transition between places or behavioral states ‪—‬ for example, if the pup just experienced something stressful or exciting. "This 'shake off' is a way of helping the animal to relieve tension and reset emotionally and physically," Miele said.

"It could be after quite an intense play session with another dog that was really fun," Crowley added. "You often see both dogs will finish playing, and then they'll both shake, and then they'll go do something else."

When to be concerned about your pet shaking its head

Although head shaking can be normal, if your pet starts doing it more often, in unusual circumstances, or while scratching or tilting their head, it might indicate a medical issue, such as an infection, parasite, irritation, neurological problem or something lodged in their ear.

"It's painful and uncomfortable, and that's the only thing that they can do, apart from stick their foot in it," Crowley said.

If you're concerned about your pet's head shaking, consult your vet. "If ear infections are left untreated, then this can result in hearing loss and risks the infection spreading beyond the tympanic membrane (ear drum) and into the middle ear, causing problems with balance and resulting in the animal becoming very unwell," Miele said.

For the most part, though, head shaking is just an adorably normal behavior that helps your pet stay clean and comfortable.

This article is for informational purposes only and is not meant to offer medical advice.

How much do you know about cats? Test your knowledge with our cat quiz!

Wild chimpanzees in Uganda are fighting a rare "civil war," which seems to have begun when a huge community divided, leading to sustained and deadly conflict between animals that had previously been allies and friends.

Conflicts between different groups of chimpanzees (Pan troglodytes) are relatively common as they compete for key resources, like fruit trees, water supplies and trees that provide suitable nesting material. However, conflicts within previously unified communities are much rarer.

About 50 years ago, primatologist Jane Goodall reported a suspected fission event in a chimpanzee community in Gombe, Tanzania, in which a larger group split into factions; males of one new faction killed an adult female and all six males in the other group over four years. But observations of the behavior were limited, and it was considered an anomaly.

Now, Aaron Sandel, an anthropologist at the University of Texas at Austin, and his colleagues have described another, much bigger, lethal conflict between the members of the Ngogo chimpanzee community in Kibale National Park, Uganda. The work was published Thursday (April 9) in the journal Science.

The chimpanzees there have been studied for about 30 years, providing extensive data on their interrelatedness and behavior. Although they were all part of a big group, they tended to form temporary "parties" that changed throughout the day as individuals moved about their territory.

But between 1998 and 2014, some of these groups became more regular cliques, such as three adult males that were consistently together.

Researchers revealed that from about 2015, the huge Ngogo community — which then numbered about 200 chimps — ruptured into two distinct clusters that lived and reproduced separately. The core of one of the groups was the clique of three adult males.

At this stage, there were still ties between many individuals in the two groups, and they still cooperated and bonded, but by 2018, the last social ties disintegrated and aggression grew during border patrols of their separate territories.

"After they split into two groups, chimps from one group began attacking and killing those from the other group and that turned into an escalated period of lethal violence," Sandel told Live Science.

Deadly raids

Raids resulted in multiple killings of adult males and, beginning in 2021, the researchers also regularly observed infanticide. The true death toll of what the researchers term a civil war is likely to have been higher, because many other individuals disappeared without clear cause, Sandel added.

"I'm sort of nervous about calling it civil war," he said. "Civil war means something very specific when we talk about humans, and chimps don't have nations and things like that, but there's an important conceptual point when thinking about war against strangers versus civil war. These are chimps that know each other."

James Brooks, an evolutionary anthropologist at the German Primate Center in Göttingen who wasn't involved in the study, told Live Science that he agrees this conflict isn't the same as a human civil war, but said the term helps people to understand the general idea.

It's still not clear why the division in the community led to such aggressive conflict, but Sandel suggested various factors that could have destabilized social ties. These include the unusually large group size, competition over food and reproduction, the deaths of five adult males and one adult female in 2014, a change from one alpha male to another in 2015 and a respiratory epidemic that killed 25 chimpanzees in 2017.

Brooks suggested the group's size could have been a factor. "Maybe they were no longer facing such an abundance of resources and became too large a group to maintain cohesion," he said.

Zoologist Liran Samuni, also at the German Primate Center and co-director of the Taï Chimpanzee Project, who wasn't part of this study, said that the Ngogo community is one of the more aggressive ones that researchers know. "The Kibale National Park is considered quite a rich environment, with the chimps living at high densities and for long life spans. But even before this split, this was one of the chimpanzee communities that was most violent in terms of encroaching on neighbors," she told Live Science.

Between 1998 and 2008, the Ngogo chimps killed at least 21 chimpanzees from neighboring groups, and expanded into their territory, resulting in population growth.

The civil war is still ongoing, Sandel said. The research paper covers data collected up to 2024, but he says further attacks have happened in 2025 and 2026.

He said the work shows that even without ethnicity, religion or political ideologies, social networks can divide, leading to collective violence.

Given that chimps are one of humans' closest two relatives, the finding reiterates how group divisions can present a danger to human societies, Brooks said, but he adds that it doesn't mean conflict is biologically determined. He pointed to bonobos (Pan paniscus) — our other closest relatives — which form stable and distinct groups. They are also aggressive, but unlike chimpanzees, they don't engage in such lethal group conflicts but form tolerant, cooperative associations, so such conflicts aren't evolutionarily determined.

"Our evolutionary past does not determine our future," he said.

How much do you know about primates like chimpanzees? Test your knowledge with our primates quiz!

For the first time in four decades, scientists have announced a confirmed sighting of a critically endangered hare in part of its native range, after spotting its completely flattened carcass on a roadside.

Researchers were traveling for fieldwork on Hainan, an island in southern China, when one member spotted the roadkill by chance. Despite the carcass's severely damaged condition, they immediately recognized it as the little-known Hainan hare (Lepus hainanus). The species, which is found only on Hainan, is among the world's most understudied lagomorphs, the mammal group that includes rabbits, hares and pikas.

The sighting occurred around 125 miles (200 kilometers) from the hare's only current known range in the island's northeast, according to a study published Dec. 15, 2025, in the journal Mammalia.

Although the hare is known to survive in some areas of western Hainan, particularly the Datian National Nature Reserve, the roadkill incident represents the first confirmed documentation of this species from northeastern Hainan since 1986, suggesting that an overlooked remnant population still exists in the region, according to the study.

"It provides hope for this nationally critically endangered species as its current range is wider than previously known," study first author Michael Hui, a conservation officer with the Hong Kong-based conservation group Kadoorie Farm and Botanic Garden (KFBG), told Live Science via email. "However, our article also provided updated information regarding the species' stronghold in the western region, which is not as secure as traditionally assumed."

Historically, L. hainanus is thought to have been widespread and abundant across most of Hainan's coastal lowlands, primarily in the northwest, west and south, according to the study.

In the 1950s, the species' population is thought to have been around 10,000 individuals. But a particularly sharp decline was observed in the 1970s and '80s, largely due to habitat loss and excessive hunting for their meat and fur.

A 2008 report estimated that there were likely no more than 250 to 500 individuals remaining on the island. Concerns over its status recently led to the Hainan hare being designated as a "critically endangered" species on China's Red List.

Outside Datian National Nature Reserve, the species is rarely reported, and even inside the reserve, everyday sightings are generally infrequent, Hui said. A recent "rapid survey" covering most of the hare's historical range in western and northwestern Hainan documented only one live individual and noted that the species was disappearing unnoticed. But a lack of systematic, island-wide survey data from the past few years means the total population is unknown.

L. hainanus is elusive, in part because it's nocturnal and most of its preferred lowland habitats lie outside protected areas, which have traditionally received little research attention, Hui said.

"We believe that every new record, even single incidental records, can help inform future surveys and proposed conservation actions," the authors wrote in the study.

Much of the hare's habitats are declining because of agricultural expansion and urban development. Therefore, an island-wide survey to understand its current status, distribution and threats is crucial for making informed conservation decisions, the study authors said.

Win-win interactions can be found across nature. These relationships, known as mutualisms, involve members of different species working together for a mutual benefit.

But relationships between two species can change over time, with those starting out as mutualistic potentially evolving into parasite-host relationships, Rob Dunn, a professor of applied ecology at North Carolina State University, previously told Live Science.

In his book "The Call of the Honeyguide: What Science Tells Us About How to Live Well With the Rest of Life" (Hachette Book Group, 2025), Dunn explores a common human-animal relationship that may force us to rethink mutualisms altogether: our relationship with cats. In this extract, Dunn looks at the origins of our connection to our feline friends, and why, on the face of it, cats could be considered "parasites of human societies, at least from a Darwinian perspective."

As we think about the ways we measure our mutualisms, it is worth considering cats. Domestic cats, house cats, under the table and on the table, cats are everywhere and we take them for granted, but what exactly do we get out of our partnership with them?

As far as I know, cats are no longer worshiped as gods. Yet they are also not our mutualists. Superficially they seem to be parasites of human societies, at least from a Darwinian perspective. They benefit from us at the cost of the food we provide to them. The collective weight of domestic cats exceeds that of African savannah elephants. And Americans alone give 15 billion calories' worth of food to house cats each day — much of it meat — roughly as many calories as would be consumed by humans in New York City in a day.

We feed them tuna; like royalty, they dine on the ocean's top predators. In exchange, what do we get back?

I concede in advance that I attempt to answer this question with trepidation. The conclusion I come to may require us to broaden our conception of what the terms of mutualism can be; they definitely require us to rethink what a cat is.

Today, hundreds of millions of house cats live with humans around the world. More than 70 million house cats can be found in the United States alone — 70 million meowing, purring, clawing beings — one cat for every four adult humans.

There have never before been so many felids [members of the cat family] on Earth. Globally, there are probably about half a billion cats, though no one has a great count. We have replaced nearly all the wild carnivorous felines of the world — tigers, lions, jaguars, and leopards — with domestic cats. Where once we feared jaguars, we are now confronted by beings we deign to give names like Edgar Allen Paw, Copurrnicus, and, all too often, Mr. Whiskers.

These household cats are all the descendants of the African or Libyan wildcat, Felis silvestris lybica. African wildcats are, and have long been, native to both North Africa and to the Levant. Their range bumps against that of European wildcats, Felis silvestris silvestris, in Turkey. As humans began to farm and store grain, African wildcats began to move into small agricultural human settlements. Once there, they ate mice and rats. They may also have eaten the snakes that ate those rodents (as highlighted in Egyptian art and, later, writing).

Studies led by the Italian cat geneticist Claudio Ottoni of the DNA present in the bones of cats found in archaeological sites have so far been unable to discover any evidence that the earliest African wildcats living with humans were genetically different from their wild-living ancestors and relatives. Their genes seem to have been nearly the same, or maybe simply the same.

At least early in cat-​human relationships, their bones were the same. The early village and city cats appear to have been the same African wildcat, simply living in closer proximity to humans. Species with this habit are sometimes called "synanthropes," which denotes nothing more than co‑occurrence, living with (syn) humans (anthrope). These cats living with humans had learned to act tame around humans, just as the humans had learned to act tame around them, most of the time.

"Tameness" is a vague word. Biologists use it to express a kind of mutual tolerance between a nonhuman animal species and humans. It comes from an ancient Indo-​European word meaning "to subdue." This root, though, is deceptive. Most tame species either have traits that lead them to behave tamely, as is the case in many island species long naive to large predators, or they choose to be tame, to walk into our worlds without menace. To be tame is to come in peace.

After walking into human cities, the partially or fully tame human-associated wildcats spread with agricultural societies. By 9,500 years ago, wildcats had arrived in places they could not get to without the help of humans. Wildcats are not native to Cyprus. Yet, they arrived. A 9,500-​year-​burial on the island of Cyprus includes an eight-​month-​old cat carefully prepared for the afterlife alongside a human. How? Ancient cats are unlikely to have engaged in long swims on their own (if you doubt this assertion, try to bathe a feral cat). Wild but tame cats were ushered/ferried/carried here and there by humans. It is likely that their human chauffeurs were scratched in the process.

In early settlements, cats and humans were friends with mutual benefits, regardless of whether either exerted any control over the other and whether either partner changed, evolutionarily, relative to the other. It was a mutualism at paw's length. The cats benefited from the messiness of humans and from the effects of that messiness on rodents. The humans benefited from the control cats could exert over rodent populations.

Today, most domesticated cats do not prey upon rats. But reports of early Egyptian cats suggest that they might have been larger than modern domestic cats. At least one Roman archaeological site in Egypt records a gluttonous cat with the bones of six rats in its stomach. In good years, the consumption of rodents, big and small, by cats might have been a kind of pleasantness for humans ("Ah, fewer mice"). In years when food was short, it likely saved lives. It also may have saved lives when diseases carried by rodents, or the fleas upon them, killed humans — diseases such as the plague. Later, cats also played a heightened role on ships, where mice and rats were gloriously abundant and where grain was a precious and relatively scarce commodity.

Where scholars of cat domestication — yes, there are a few, though they'd fit at a long dinner table — begin to differ is whether the predation of cats on mice, rats, and snakes continued to matter as human settlements grew ever larger. This is a subject that could be partially addressed through mathematical models.

I hypothesize that in small settlements in the ancient Levant, or, later, in Mesopotamia, cats were probably successful in reducing the abundance of mice, and maybe rats, and so, too, their negative effects. But in big urban centers, such as those that emerged with the New Kingdom period in Egypt (1600 BCE), grain was being stored in immense quantities. Where there were whole buildings full of grain, in cities practically spilling over with grain, it seems unlikely that one could keep enough cats around the grain for the cats to matter.

It would have taken hundreds or even thousands of cats milling around the granary, meowing and acting pissy. It is entirely possible, then, that as early grain-​based settlements grew, the functional role of cats in rodent and snake control decreased.

It is in this very period that cats began to appear in new forms in Egyptian art. By 3,500 years ago, cats were no longer shown hunting. Instead, they lurked under tables or chairs, often alongside powerful Egyptian women. As Claudio Ottoni pointed out to me, typically, these "under-​chair" cats were leashed, perhaps an indication that they may have been tame but not yet so docile as to pose unrestrained for an artist. The under-​chair cats seem to indicate that as the human-cat relationship persisted, new kinds of bonds were forming, bonds that no longer related simply to the role of cats in controlling pests. But why?

"Hippie" bonobos are just as aggressive as "warrior" chimpanzees, according to a new study. However, the findings also reveal some key details about which sex is instigating the aggression. Bonobo females were more likely to attack males, while male chimps were more aggressive towards females. Female-on-female aggression in both species, they found, was significantly lower.

The work was in captive animals in zoos, so it may not apply to wild bonobos and chimps ‪—‬ but it adds to a growing body of recent research suggesting bonobos aren't as peace-loving as once described.

"I don't think that they're as peaceful as previously thought," study co-author Nicky Staes, a researcher at the Antwerp Zoo Centre for Research and Conservation in Belgium, told Live Science.

Bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) are our closest living relatives. The two species are geographically separated by the Congo River in Africa and evolved from a common ancestor between 1.5 million and 2 million years ago.

Although they are closely related, chimps and bonobos look and behave differently. Bonobos are smaller, with a more slender build, and the differences between the sexes are less pronounced than in chimpanzees. Bonobo communities are led by female coalitions; this is seen as a strategy for females to gain power over the larger males. Chimpanzees, on the other hand, have males at the top of their hierarchies.

Aggression is an important social behavior in apes, as it helps them protect territory, identify mates, assert dominance and secure resources. This aggression can range from vocal expressions of anger to physical attacks.

In the past, bonobos were seen as chimps' peace-loving "hippie" cousins because they were thought to be less warlike and more likely to use sex to resolve conflict. But recent studies have started to upend that idea. In one recently reported incident, five wild female bonobos viciously attacked a male in the Democratic Republic of Congo.

In the new research, published Wednesday (March 11) in the journal Science Advances, researchers show that bonobos are just as aggressive as chimps — but they target males and females differently.

Little difference in overall aggression

The team analyzed how 22 zoo-based groups of chimps and bonobos in Europe interacted. A researcher sat in front of the enclosure and noted each act of aggression, which ranged from shouting to physical violence, that occurred throughout the day. The team spent two to three months at each zoo, recording a total of 3,243 instances of aggression from all of the apes older than 7 years. Seven is the youngest age at which researchers have recorded a bonobo male reproducing, Staes said.

They found that there were 1,368 instances of directed aggression from bonobos and 1,875 from chimpanzees. About a third (1,193) of the instances were "contact" aggression, meaning there was physical violence between the individuals rather than just shouting or other less-violent forms of aggression. Once the data were controlled for sex, relationship and context, there was little difference in overall aggression between chimps and bonobos.

"You don't find that chimpanzees are more aggressive," Staes said. "Bonobos are equally aggressive." Among chimpanzees, males were mostly responsible for the conflicts. Male and female bonobos, on the other hand, were equally likely to pick a fight. "There's no difference between the sexes in bonobos, which was a bit surprising to us," Staes said.

However, there were differences in which sex got targeted. Male chimps were aggressive toward both females and other males, and they were also more likely to get physically violent. Female bonobos were more likely to be aggressive toward bonobo males. While there is male-male aggression in bonobos, there is seldom female-female aggression, Staes said.

But bonobos are better at making up, she said, adding that in an upcoming study, the team plans to describe how the different groups resolved conflicts.

There were also stark differences between the levels of aggression among the bonobo groups in different zoos — more so than in chimps. "Our findings contribute to a growing body of evidence suggesting that behavioral patterns in Pan, including aggression, may be more influenced by group identity than by species-wide traits," the authors wrote.

Zoos offer an interesting perspective on ape behavior. Some researchers argue that chimpanzees are more warlike because food was less available on their side on the Congo River and they had to compete with gorillas for resources. Conversely, bonobos had more food and fewer predators.

In zoos, these environmental factors are no longer at play. "The main benefit is that you take the two species out of their ecology and you really get the behavioral differences that are due to, for example, genetic changes that have occurred since the split from each other," Staes said.

Sonya Pashchevskaya, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany who was not involved in the research, said she welcomed the new insights. "This study is particularly important in light of the 'hippie' bonobos notion famously originating in the captive setting," she told Live Science. "It is great to see the myth methodologically challenged in such a setting and with multiple groups involved."

"Aggression, as a means to navigate conflict, is a normal part of life," Pashchevskaya said. While chimpanzees are more prone to taking it to violent extremes, bonobos may "reserve real violence for the worst dangers."

The new insight into bonobo aggression could provide more clues about conflict among our closest relatives. "While conflict is inevitable," Pashchevskaya said, "there exist varying aggressive expressions, and from both sexes."

Two marsupial species that were thought to have gone extinct at least 6,000 years ago have been found on the island of New Guinea.

The discovery was far from swift, with the first clues of the marsupials emerging in 1999 and requiring ample photographic evidence to confirm. But 27 years later, scientists are now sure that the ring-tailed glider (Tous ayamaruensis) and the pygmy long-fingered possum (Dactylonax kambuayai) are alive in the remote rainforests of the Vogelkop Peninsula in Papuan Indonesia.

"The Vogelkop is an ancient piece of the Australian continent that has become incorporated into the island of New Guinea," Tim Flannery, a professor at the Melbourne Sustainable Society Institute and a distinguished visiting fellow at the Australian Museum who led the research, said in a statement. "Its forests may shelter yet more hidden relics of a past Australia."

Marsupials are mammals with a characteristic pouch to hold newborns until they are fully developed. The pygmy long-fingered possum and the ring-tailed glider were previously known to scientists only from fossils in Australia dating to the last ice age and the first phase of the early Holocene epoch, which is the current period of geological time.

The pygmy long-fingered possum is a striped marsupial with one digit on each hand that is twice as long as the next-longest finger. The ring-tailed glider is a relative of Australia's three greater glider (Petauroides) species, which are named after their ability to soar through forest canopies using furry membranes that extend from their elbows to their ankles. The ring-tailed glider is smaller than its Australian cousins and has unfurred ears, as well as a tail adapted for grasping and wrapping around objects such as branches.

The pygmy long-fingered possum and the ring-tailed glider are what researchers call "Lazarus taxa," meaning they are animals that vanish from the fossil record and seem to go extinct for an extended period before reemerging as living species. Their recent discovery was possible thanks to Indigenous communities in Papuan Indonesia that helped Flannery and his colleagues track down the animals. Specifically, the researchers collaborated with local elders from the Tambrauw and Maybrat clans.

"The discovery of one Lazarus taxon, even if thought to have become extinct recently, is an exceptional discovery," Flannery said. "But the discovery of two species, thought to have been extinct for thousands of years, is remarkable."

Some local Indigenous groups consider the ring-tailed glider to be sacred and deserving of the highest protection, which might help explain why the species has remained hidden, New Scientist reported.

Ring-tailed gliders form lifelong pair bonds and raise only one young per year. Like greater gliders, they nest in tree hollows, which makes them extremely vulnerable to logging.

The pygmy long-fingered possum also faces threats from logging. Its ears may be adapted to detect low-frequency sounds, including noise from wood-boring beetle larvae, which the possums dig out from rotting wood with their fingers to eat, Flannery told New Scientist.

Much remains unknown about the specific range and ecological needs of each species. The exact locations where they were found is being kept secret to prevent wildlife traders from targeting them. What is known so far about the marsupials was published March 6 in two peer-reviewed studies in the journal Records of the Australian Museum.

"The findings underscore the critical importance of preserving these unique bioregions and the value of collaborative research in uncovering and protecting hidden biodiversity," Flannery said in the statement.

Striking first-of-its-kind footage has captured the moment a red fox preyed on a 1-month-old gray wolf pup at a nature reserve in Italy.

Scientists monitoring gray wolves (Canis lupus) in the Castelporziano Presidential Estate, a nature reserve about 15.5 miles (25 kilometers) from Rome, had noticed a female with a swollen abdomen. GPS monitors showed her repeatedly visiting a secondary den, suggesting she had already given birth.

Strategically placed cameras revealed two male pups exploring outside the den just days before the attack. Then on May 16, 2025, a red fox (Vulpes vulpes) was filmed entering the den. The first pup escaped, but within seconds the fox exited the den with a pup in its mouth.

At this point the clip cuts out, so the footage does not show the fox or pup leaving the den, but researchers believe the fox likely ate the wolf pup.

The study documenting the observation was published Feb. 13 in the journal Current Zoology.

Mortality rates in wolf pups are high, approximately 40% to 60% of wolf pups die every year. They usually die from starvation, disease, extreme weather and poor body condition. But this video shows predation may also play a small role in their high mortality rates.

The paper is part of a long-term project led by study co-author Marco Apollonio, a researcher at the University of Sassari, to understand more about wolves in Italy.

Tracking wolf pup birth and survival rates is important to help researchers better understand longer-term population dynamics, said study lead author Celeste Buelli, a doctoral student at the University of Sassari, who led the fieldwork and den monitoring. But it isn't easy.

Direct observations of wolf pup deaths are rare as they spend their time in hard-to-monitor dens, she said. The footage is "striking" as it shows an "intense event with a very young animal," she told Live Science.

Study co-author Rudy Brogi, a researcher at the University of Sassari, told Live Science it is likely that the fox ate the pup, as foxes are typically opportunistic feeders — meaning they do not rely on one specific type of prey and adapt their diet depending on availability. In later footage, only one pup can be seen.

It could also be that the fox was simply removing competitors from the area. But Brogi thinks this is unlikely given that foxes sometimes benefit from wolves by scavenging on their leftover kills.

David Macdonald, a zoologist at the University of Oxford in the U.K., has spent decades researching foxes and was not involved in the study. He told Live Science that competing species can kill or prey upon one another, but this behavior "generally involves larger canids harassing or even killing smaller ones."

Whether this behavior is common is unclear from a single video. Brogi said it is "plausible" that it occurs more often than is reported, but more research from "multiple dens and contexts" is needed.

Animal quiz: Test yourself on these fun animal trivia questions

Tigers will soon roam Kazakhstan for the first time in over 70 years as conservationists undertake a gargantuan effort to restore part of their lost habitat.

The last of Kazakhstan's Caspian tigers disappeared in the late 1940s, after years of hunting, habitat loss and declines in prey numbers. Now, the Central Asian country has an ambitious plan to reintroduce the world's largest cats to their historic lands.

So far, two captive tigers (a male and a female) are already in Kazakhstan as part of a breeding-and-release project, while the country is expecting its first wild tigers to be transported from Russia in the first half of 2026. However, for the program to be a success, the tigers need plenty of places to live. That's where an enormous tree-planting project comes in.

Last year, the Kazakhstan tiger reintroduction program — led by the government of Kazakhstan with support from the World Wildlife Fund (WWF) and the United Nations Development Programme — planted 37,000 seedlings and cuttings near a giant lake in southeast Kazakhstan's South Balkhash region, where tigers used to live, according to WWF Central Asia. This adds to the 50,000 seedlings planted between 2021 to 2024.

Tree planting is a key part of Kazakhstan's massive ongoing greening initiative. The country has planted around 1.4 billion trees since 2021, and officials say they are on track to reach 2 billion trees by 2027.

In South Balkhash, newly planted trees serve as a foundation for recovering ecosystems that sit alongside already-forested lands. The trees provide shelter and water access, as well as food for the tiger's prey: hooved mammals (ungulates) like boar and Bukhara deer (Cervus elaphus bactrianus, also called Bactrian deer).

"Already, wild ungulates have been seen foraging on the restored sites, indicating that the ecosystem is beginning to function," a spokesperson for WWF Central Asia told Live Science in an email. "Each planted seedling is therefore a direct contribution to the future of the tiger in Kazakhstan."

The planting zone encompasses around 2.5 miles (4 kilometers) of shoreline along Lake Balkhash, which covers roughly 6,500 square miles (17,000 square km) and is the largest lake in Central Asia and the 15th-largest lake in the world. The new vegetation — which includes 30,000 narrow-leaf oleaster seedlings, 5,000 willow cuttings and 2,000 turanga poplar seedlings — creates growing "islands" of forest that regulate the flow of water to stabilize floods and overflows.

WWF Central Asia attributes the increase in planting in 2025 to the accumulated experience of the staff, as well as to factors like improved planting techniques and expanded partnerships. However, the pace of the ecosystem's recovery and its suitability for tigers will depend on a variety of factors, including the climate, stability of water resources, and growth of vegetation.

Bringing back tigers

The tigers that used to live in Kazakhstan were part of a now-extinct Central Asian population known as Caspian tigers. However, the living Amur tigers found in the Russian Far East and China (and potentially North Korea) can serve as suitable replacements. A 2009 study published in the journal PLOS One found that Caspian and Amur tigers were likely part of the same population until human activity forced them apart in the 19th century, meaning they're essentially the same animal.

The reintroduction program welcomed two captive Amur tigers in 2024, and they appear to have adapted well to life in Kazakhstan. These tigers, a female named Bodhana and a male named Kuma, came from an animal sanctuary in the Netherlands in 2024 and are currently living in an enclosure within the Ile-Balkhash Nature Reserve. Bodhana and Kuma are used to life in captivity, so they'll never be released, but the hope is that their offspring will form part of a new founder population of Kazakhstan tigers.

However, as there's no guarantee that Bodhana and Kuma will breed or produce suitable offspring, so the bulk of the new population will be made up of wild tigers imported from Russia.

Kazakhstan officials are expecting to receive the first tigers from Russia in the coming months. WWF Central Asia told Live Science that it hasn't been confirmed where the Russian tigers are coming from, but "based on publicly available information and recent media reports, it is understood that the Amur tigers expected in the first half of 2026 are from the wild."

Reintroducing large predators is a delicate and risky process, particularly when those predators are capable of harming humans and livestock. But it can be done; a 2024 study published in The Journal of Wildlife Management found that a tiger reintroduction attempt in Russia was largely a success. Researchers cared for six orphaned wild cubs and prepared them for re-release into their natural habitat. The tigers caught their own prey and survived.

However, the study noted that one rehabilitated tiger killed multiple domestic animals, including more than 13 goats in a single event, and failed to demonstrate adequate fear of humans. That tiger was subsequently recaptured and placed in a zoo.

WWF Central Asia said Kazakhstan's program is prepared to resolve any incidents that involve human conflict with its released tigers. Measures include creating a special team that will continuously track released individuals and respond to any potential human-wildlife conflicts.

"The group's main tasks include regular patrols, monitoring tiger movements via satellite collars, early detection of potential approaches to settlements, and rapid response measures," the WWF Central Asia spokesperson said.

The program is also working with local communities to raise awareness about tigers and how to behave in their presence, as well as promoting sustainable development in those communities by offering grants for agriculture and ecotourism, according to WWF Central Asia.

"All of this forms part of a long-term strategy for peaceful coexistence between people and predators," the spokesperson said. "A compensation scheme for local residents is also planned in cases where tigers cause livestock losses."

For the first time, scientists have experimentally shown bonobos (Pan paniscus), our closest living relatives along with chimpanzees (Pan troglodytes), can engage in pretend play — something previously assumed to be unique to humans.

Just like 2-year-old children can, Kanzi, a unique bonobo who could understand English, kept track of imaginary juice and grapes during pretend tea parties, according to a study published Thursday (Feb. 5) in the journal Science.

Although Kanzi, who died in March 2025, did not initiate the pretend play, his ability to follow along shows he had some of the mental building blocks needed to imagine pretend objects and scenarios.

"We were really in awe at this finding," study co-author Christopher Krupenye, an assistant professor of psychological and brain sciences at Johns Hopkins University, told Live Science. "What we're seeing in this case is that … something that seems to be fundamentally human and is emerging early in our human development is also shared with our closest relatives," he said.

This suggests the human capacity to imagine objects that aren't really there could have evolved before humans and bonobos split from our last common ancestor over 6 million years ago, Krupenye said.

Imagined realities

Previous anecdotal evidence has hinted that captive and wild great apes engage in pretend play. For example, a wild 3-year-old chimpanzee in Guinea was observed playing with a discarded human-made leaf cushion by placing it on his head. A captive bonobo also "picked" and "ate" blueberries from a photograph of real blueberries.

But because the anecdotal examples could be explained by alternative explanations, such as the apes believing the pretend objects were actually real, Krupenye and his colleague Amalia Bastos, a comparative psychologist at the University of St Andrews in the U.K., wanted to bring the question of "can animals really pretend?" into a controlled, experimental setting.

Because Kanzi could understand and respond to English, he was the obvious first animal to study, Krupenye said.

First, Kanzi was trained to point to the vessel containing juice. He was shown two see-through bottles, one containing juice and the other empty, and he was asked to point out where the juice was. If he answered correctly, he was rewarded with some of the juice. Kanzi got a perfect score over the 18 repeats of this training phase.

In the test trials, an experimenter placed two transparent empty cups side-by-side on a table in front of Kanzi. Next, they pretended to pour juice from an empty jug into each cup, then poured the pretend juice from one of the cups back into the jug. Kanzi was then asked to point to the location of the cup with the juice, but he was never told if he was correct, and wasn't rewarded.

Kanzi correctly identified the location of the pretend juice 68% of the time, which suggested he could keep track of the imaginary liquid.

But the possibility remained that he simply thought the empty cup actually contained real juice. To check if this was the case, the team ran a second experiment where they placed a juice-filled cup and an empty cup on a table. They pretended to pour juice into the empty cup and then held the empty jug over the full cup without doing the pouring motion.

Krupenye said that if Kanzi really thought there was juice in both cups, he would have chosen them at equal frequency. But, when asked which cup he wanted, Kanzi selected the cup containing real juice 77.8% of the time, suggesting he could clearly distinguish real from imaginary juice.

"That sort of gave us confidence that we were really looking at some ability to track imaginary or pretend objects," Krupenye said.

Bastos said she was still a little skeptical at this point — Kanzi's ability to point out where the pretend juice was could have been a fluke. So the team repeated the same procedure but with a pretend grape. Kanzi correctly identified the location of the imaginary grape in 68.9% of trials.

"By the time we finished experiment three, I was very confident that what we saw was what we saw," Bastos said.

The research is limited as only one bonobo was tested, but is nonetheless the first clear evidence that great apes can engage in pretend play, Laura Simone Lewis, an evolutionary anthropologist and psychologist at the University of California, Santa Barbara, who was not involved in the research, told Live Science in an email.

"This is a huge development for our field, because it provides direct evidence to support the anecdotal reports from the wild that our great ape cousins can use their imaginations for all sorts of activities, including pretend play," she said.

This research demonstrates that Kanzi could understand shared pretense created by humans, but not that he could produce pretend scenarios himself.

"I think it would be a big leap to say that, because of this, in some sense we're seeing something comparable to what we see in 2-year-old children, where you typically routinely see pretense production including things like drinking from empty cups and so forth," Paul Harris, a psychologist at Harvard University who was not involved in the study, told Live Science.

Krupenye and Bastos hope that pretend play can now be explored in other great apes. "If the anecdotes are right, it should be the case that other apes also share this capacity," Krupenye said.

Primates Quiz: What do you know about our closest relatives?

A bleak photograph shows a mother polar bear and her three cubs resting on bare ground and moss, their coats brown with mud.

The image is on the shortlist for this year's Wildlife Photographer of the Year Nuveen People's Choice Award — a contest in which members of the public vote for their favorite among 24 images that have been selected by the Natural History Museum, London, and a panel of photography and wildlife experts.

Photographer Christopher Paetkau captured the slumbering polar bears along the Hudson Bay coast in Canada as they traveled north toward the Arctic. The family paused in the summer heat to nap, the mother and one of the cubs falling asleep while the two other cubs kept watch with their heads resting on their mom's furry back.

The touching new photograph is a reminder that global warming endangers polar bears by shrinking their sea ice habitat, forcing them to find new sources of food elsewhere. Unlike other bears, polar bears (Ursus maritimus) do not hibernate. Previously, most polar bears spent the entire year on the ice hunting their favorite prey of ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus). But with sea ice declining each year, polar bears now have to seek out more land-based prey, such as reindeer.

Another image of a polar bear is also shortlisted for this year's People's Choice Award. It captures a cub during a hunting trip on the Norwegian archipelago of Svalbard that ended in tragedy when the baby bear and its mother approached a human settlement. The mother bear was found dead shortly after, and police officers shot the cub because it seemed aggressive.

Voting for the Nuveen People's Choice Award is now open online until March 18 for anyone to select the winner of the people's choice award.

The winning image and four runners-up will be announced March 25.

"Whether showcasing fascinating behaviour or platforming a powerful story, this year's selection of images is truly exceptional, and we can't wait to see which one will be chosen as the public's favourite," Douglas Gurr, the director of the Natural History Museum, said in a statement shared with Live Science.

The winning image will be displayed along with 100 images from last year's Wildlife Photographer of the Year competition in an exhibition at the museum that's open until July 2026. Wildlife Photographer of the Year is developed and produced by the Natural History Museum.

You can see the images that made it onto the shortlist here.

After wolves were reintroduced to Yellowstone National Park, cougars — that had only regained a foothold a few decades earlier — were able to coexist due to their diets changing and the varied landscape of the park, according to new research.

Run-ins between wolves (Canis lupus) and cougars (Puma concolor, also called mountain lions and pumas) in Yellowstone National Park happen when wolves steal prey from — and sometimes kill — cougars, and this dynamic becomes more harmonious when cougars shift to eating smaller prey, according to a new study published Jan. 26 in the journal PNAS. Successful wolf and cougar coexistence in Yellowstone, the findings suggest, depends more on the diversity of prey and the availability of escape terrain for cougars than it does on the overall abundance of prey.

"Yellowstone is a fascinating system because it's got the full complement of large carnivores and migratory ungulates that North America used to have," Chris Wilmers, a wildlife ecologist at the University of California, Santa Cruz who was not involved in the new study, told Live Science. "A lot of these species are coming back –– wolves were reintroduced, mountain lions and grizzly bear numbers have been recovering –– so it's also a system that's in flux. As these populations restore themselves, it's super interesting to look at these species' effects on each other."

Cougar and wolf habitats are increasingly overlapping in the western United States. Throughout the first half of the 20th century, both species were nearly eradicated from the U.S. due primarily to hunting. Cougar populations began to rebound in the 1960s under new protections, and wolf reintroduction began in the 1990s and benefited from expanded legal protection.

Both species are now prevalent throughout the western U.S., but scientists are still working to understand the animals' population dynamics and their impacts on the broader Yellowstone ecosystem.

The new study analyzed nine years of GPS data from collared wolves and cougars, combined with field observations at almost 4,000 sites throughout Yellowstone. The researchers found that wolves occasionally kill cougars, but cougars do not kill wolves.

These findings align with previous work that showed wolves were the more dominant large carnivore in this food web, even though the two species have similar body sizes. Wolves likely dominate because they move in packs, whereas cougars are solitary, which means wolves can run cougars off and steal their prey, said lead study author Wesley Binder, a doctoral student in the Department of Fisheries, Wildlife, and Conservation Sciences at Oregon State University.

"These interactions are very one-sided," Binder told Live Science. "But cougars have the ability to adapt in some ways."

Both cougars' and wolves' diets are changing, according to the new findings: Between 1998 and 2024, elk went from constituting 95% to 64% of wolf diets, and from 80% to 53% of cougar diets, likely because Yellowstone elk (Cervus canadensis) populations are decreasing more broadly.

This decline led to changes in wolf and cougar interactions. "If cougars kill larger prey like elk, that gives wolves more time to find the cougar sitting on that kill," Binder said. "We found that wolves and cougars were six times more likely to interact when cougars killed elk, compared to deer. Deer are less than half the size of elk, so cougars eat them a lot faster, and wolves have a lot less opportunity to discover those kill sites."

Shifting cougar diets from declining elk numbers led to fewer interactions with wolves overall. Instead of elk, cougars began eating smaller prey, like deer. Wolves, they found, started eating more bison.

"It's important to realize that's why the cougars switched, but in doing so, it made them less vulnerable to scavenging and potentially getting killed by wolves," Wilmers said.

The terrain, the findings showed, also shapes the animals' encounters. When surrounded by rugged terrain or trees they can climb, cougars had fewer dangerous encounters with wolves.

Yellowstone's diversity of both prey and landscapes seems to be a sweet spot for wolf-cougar coexistence. Both species' populations are currently stable. "Wolves and cougars prefer different habitat, and Yellowstone has different habitat that suits each of these carnivores," Binder said.

The findings reveal the ideal landscape and prey characteristics for the stable coexistence of two large carnivore species — and how clashes between predators can have a ripple effect on the whole ecosystem.

"We're always trying to understand what the impact is of large carnivores on prey [populations]," Wilmers said, "and what the interactions are between the large carnivores, and how they might combine or cancel out each other's influence on prey. … It's the beginning of unraveling that story between wolves and [cougars]."

Same-sex sexual behavior among primates could be shaped partly by specific environmental and social conditions, according to a new study comparing 59 species.

Same-sex sexual behavior (SSB) in animals is increasingly recognized in the scientific community as widespread, as it's documented across the animal kingdom in about 1,500 species. Untangling how and why it emerged across so many diverse species is challenging, however. The new study, published Jan. 12 in the journal Nature Ecology & Evolution, found SSB may be beneficial — at least for primates — when ecological conditions are harsh and social conditions are complex.

While the study authors emphasized that this research on SSB in nonhuman primates does not address modern human sexual orientation or identity, they hope the findings will foster open discussion about the benefit of sexual diversity in nature and society.

"[The findings] do suggest that the orientation toward individuals of the same sex has a very strong evolutionary history, and it's nothing bizarre or derived or unnatural," said Durham University primatologist Zanna Clay, who was not involved with the new study. "In fact, it's likely part of the evolutionary fabric of our societies."

Primate same-sex bonding to navigate harsh conditions

Research suggests SSB facilitates bonding in socially complex animals. In bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), it is associated with reduced tension, conflict resolution and the strengthening of alliances. For golden snub-nosed monkeys (Rhinopithecus roxellana), SSB and grooming strengthen social bonds in harsh, cold climates with scarce resources.

Genes also seem to play a role. In a 2023 study of rhesus macaques (Macaca mulatta), Vincent Savolainen, a biologist at Imperial College London, found SSB to be about 6.4% heritable, meaning the tendency toward this behavior can be passed down genetically from parents to offspring. But such a small percentage leaves a lot of uncertainty around what else might cause it to arise.

To explore the ecological and social context, Savolainen and colleagues conducted a meta-analysis of SSB studies across primates. Of the 491 species, they found the behavior documented and prevalent in 59 species. SSB is more likely to occur when species face a drier environment, scarcer resources, and a lot of predators, according to the study. It is also more common in species with complex social systems, greater size differences between males and females, and longer lifespans.

These trends suggest SSB might serve as a social strategy to reinforce bonds, manage conflict or build alliances, driven by the ecological and social pressures a group faces. "Species that have particularly challenging environmental and social pressures have evolved, independently of common ancestry, same-sex sexual behavior as a way to manage the pressure and navigate the social dynamic," Savolainen said, "forming coalitions, bonding, helping them deal with the challenges they face."

If predators are especially abundant, for example, having a socially close group that can trust each other's alarm calls is beneficial, Savolainen said; SSB offers one way to form or maintain relationships.

Chimpanzees and bonobos are known to engage in SSB when navigating ecological challenges, said Clay. "In a resource-poor situation, you need to cooperate and learn to tolerate each other," Clay said. "If there's food scarcity, having techniques to maintain and keep social bonds going is important."

However, while the trends are notable, it's not so simple to draw parallels across species that display SSB. "It points to some common explanations that might cut across deep taxonomic divisions, but there is a risk you're obscuring some of the nuance in individual lineages," said Nathan Bailey, an evolutionary biologist at the University of St Andrews who was not involved with the new study. "Does this behavior emerge for different functional reasons, under different selective pressures, in different lineages? They're starting to scratch the surface of that."

Savolainen said SSB has been traditionally underreported, so the new findings highlight its significance in a broader understanding of primate behavior. "Same-sex behavior is as important as feeding, fighting, or looking after young," he said.

The research could help paint a more complete picture of social and sexual behavior in primates. "People tend to separate reproductive sex and social sex, whereas actually I think the social element of both is very important and should be integrated," Clay said.

But can these findings shed any light on human behavior? Our early hominin ancestors likely experienced various ecological and social pressures, including those linked to SSB for the primates in this study, the study authors pointed out –– but it's unclear whether these pressures would have contributed to the evolution of same-sex sexual orientation in hominin species in a similar way.

Generalizing the results to humans is tricky, according to the researchers and experts, without behavioral data from our hominin ancestors, and considering modern human culture and identity is so complex.

"I don't think this tells us much about what's going on in humans," Bailey said. "There seems to be a huge diversity of explanations [of SSB] across animals, even in closely related lineages, so it doesn't stand to reason to me that any one particular explanation in animals would map onto human beings."

The study also points to a key reason primates, including humans, have succeeded so well across the globe: adaptability. "We're not fixed to one mating system, one behavioral system," Clay said. "To me, the fact that sexual behaviors can expand [under different conditions] reflects that behavioral flexibility which is really important for primate success."

Prisoners on Alcatraz once risked the perilous waters in San Francisco Bay to escape the island's high-security prison. Now, a wily coyote has been filmed doing the opposite: swimming to Alcatraz Island for the first time.

Videos posted to social media show the coyote (Canis latrans) paddling to the southern edge of Alcatraz Island as the sun sets over the bay. The coyote then struggles onto the island's rocky shoreline, visibly shaking and fatigued.

Stanley Gehrt, a professor of wildlife ecology at The Ohio State University and author of "Coyotes Among Us," said he was shocked and astonished at the footage.

"There's a reason why people have had a difficult time making that swim," Gehrt told Live Science.

The videos were captured by an unidentified person visiting the island on Jan. 11. They then shared the footage with Aidan Moore, a guest relations employee for Alcatraz City Cruises, who alerted park rangers, San Francisco news website SFGATE reported.

"Coyotes can be commonly seen throughout our San Francisco and Marin parklands but never before on Alcatraz," Julian Espinoza, a spokesperson for the Golden Gate National Recreation Area, told SFGATE. "This was the first time our park biologists observed anything like this."

Coyotes are intelligent and versatile creatures that are known to swim. Gehrt said he has seen coyotes swimming across lakes in the Chicago region as part of his long-term research program, the Urban Coyote Research Project.

"In some cases, they prefer to swim across a lake rather than run around it," Gehrt said.

However, Gehrt typically only sees coyotes swim a few hundred yards in relatively calm lake conditions, which are nothing like the waters surrounding Alcatraz. The island sits in the middle of a cold estuary with strong currents — one of the reasons Alcatraz was seen as a good spot for its now-decommissioned prison.

Some prisoners are presumed to have drowned trying to escape the island, which is more than a mile (1.6 kilometers) from the mainland, and while humans do make the swim recreationally today, they do so with the benefit of wetsuits, training and guides.

It's uncertain how the coyote came upon Alcatraz Island. The videos begin with the animal already in the water with no sign of where it originated. However, Gehrt thinks the coyote must have had a tough journey. "Once it emerged from the water, it certainly looked like it had been swimming for a very long time," he said. "The animals I've seen come out of the water from their swims don't look as distraught as that or as tired and worn out, so it clearly was a pretty extensive swim."

Coyotes have previously been filmed swimming to Angel Island, another island in the bay, which coyotes have inhabited since 2017, KCRA 3 television station previously reported. Angel Island is closer to a mainland shore than Alcatraz. However, Angel Island is north of Alcatraz, so while it's closer to the mainland north of the Golden Gate Bridge, a coyote on Angel Island would have to swim farther to reach Alcatraz than a coyote on the San Francisco mainland south of the Golden Gate Bridge.

SFGATE reported that the Alcatraz City Cruises' boat captain had told Moore of unusual currents in the bay, likely the result of runoff from recent storms. It's possible that the coyote may have been swept up during a shorter swim and ended up near Alcatraz.

Gehrt said that coyotes don't always go into the water voluntarily. They sometimes use it as a means of escape from humans and other coyotes, which are very territorial. However, Gehrt also speculated that this coyote may have been motivated by opportunity, including the potential for food resources and territory.

Coyotes were once confined to the prairies and deserts of central and western North America. But in the 1800s, humans facilitated their expansion by creating more open habitats through logging, agricultural development, and by hunting their competitors — wolves and cougars.

As humans took over more and more land, coyotes became regular city slickers. Their flexible nature and diet now helps them thrive in cities like San Francisco, where they favor fragments of woody and shrubby habitat, as well as parks and golf courses.

Christine Wilkinson, a conservation scientist who has studied Bay Area coyotes for the University of California, Santa Cruz and the California Academy of Sciences, told SFGATE that the coyote in the video was likely trying to establish its own territory.

Wilkinson suspects that the coyote came from a pack in the Coit Tower, which is on the mainland south of Alcatraz, and where there is little green space for coyotes. Furthermore, coyotes wanting to disperse south of Coit Tower would face Interstate 280 and the risk of being struck by a vehicle, so taking to the water might have seemed like a safer option.

Coyotes typically look for new territory in the fall and early winter, but it's not unheard of for this to happen in January, Wilkinson said. The coyotes are also now in mating season, which runs from January to March.

There haven't been any sightings reported since the swimming coyote was filmed arriving on Alcatraz. Wilkinson told SFGATE that she thought the animal looked "pretty weak" but added that coyotes are "incredibly resilient." Wilkinson also noted that the island has plenty of food for a coyote, including eggs, chicks, rats and mice.

Coyotes live in small family groups, made up of an alpha male, an alpha female and their close relatives. Solitary coyotes are typically young individuals, between around 6 months and 2 years old, of either sex, that are looking to find another group or establish their own territory, according to the Urban Coyote Research Project. Gehrt has recorded a coyote traveling more than 150 miles (240 km) across the southern part of Ohio as part of its natural dispersal, which included crossing the Ohio River.

"It speaks to the animal's ability to overcome a number of different challenges and their ability to explore and take advantage of whatever opportunities they can find," Gehrt said.

For the first time ever, a cow has been documented not only using a tool but selecting which part to use when scratching at different parts of her body.

Witgar Wiegele, an organic farmer and baker in Austria amid the slopes of the Eastern Alps, sometimes saw Veronika, his Braunvieh or Swiss brown cow (Bos taurus) picking up sticks in her mouth and using them to scratch herself.

She'd been doing it on and off for about nine years without any training when he sent the footage to Alice Auersperg, a cognitive biologist at the University of Veterinary Medicine, Vienna.

"People tend to think that anything an animal does with an object is tool use and sometimes you get sent videos of animals randomly interacting with objects, like 'My cat is using a tool because she's using my Amazon box as a house.' But this particular video was different," Auersperg told Live Science. "It showed the kind of a behavior I would expect from the stricter definitions of tool use, where you see a tool is an embodied part of the animal and it is used as a direct elongation of her body."

After seeing the video, Auersperg and her colleague, Antonio Osuna-Mascaró, an animal cognition researcher also at the University of Veterinary Medicine, set out to meet Veronika and put her to the test. They repeatedly placed a deck brush, or broom, on the ground in front of her in a random orientation to see what she would do.

"We decided to use a broom because a broom has a functional end and a non-functional end. So our prediction was that if Veronika is really sensitive to the functional properties of the tool, she will prefer to use the broom end," Osuna-Mascaró told Live Science.

Veronika picked up the object by the handle end and scratched herself with the broom end about 2.5 times more often than doing it the other way round, he said. But after a while, a more nuanced pattern emerged.

After 70 sessions, if Veronika was going to scratch the thick skin of her back, she generally picked up the broom in her mouth by the thin end and gave herself a good rigorous scratch with the big, abrasive brush. If she wanted to scratch a more delicate area, like her navel or udder, she would pick up the broom by the brush end and rub herself gently with the thin handle.

The study was published in Current Biology on Monday (Jan. 19).

Veronika's behavior also indicated that she knew which body part she intended to scratch before picking up the broom, rather than just using a tool in whatever orientation she happened to pick it up, Osuna-Mascaró said.

For example, she would raise her tail in anticipation when she was going to scratch her delicate anal region and readjust her grip on the tool to ensure she could reach it, he said.

The readjustment was no easy matter. To pick up the brush, Veronika would roll out her tongue, wrap it around the tool, bring it up to her mouth and press it between her lower teeth and the hard dental pad at the top of her mouth, said Auersperg. This means the tool sits there very firmly and can't be easily adjusted. Sometimes, Veronika would let go of the tool before scratching, then grab it again in a different place and then direct the tool at the body region that she wouldn't have been able to reach with the previous grip.

This behavior is very different from a cow just using a scratching pad, Auersperg said. Scratching yourself against something is just an interaction between an animal and an object. To qualify as tool use, the animal has to be responsible for the orientation of the object, as Veronika is.

"I have absolutely no doubt that this is tool use," Josep Call, a comparative psychologist at the University of St Andrews in Scotland, who wasn't involved in the study, told Live Science. "They clearly show that the cow uses the brush, the one end or the other, depending on the area that it is scratching. That's very nice."

Gloria Sabbatini, an animal biologist at the National Research Council of Italy's Unit of Cognitive Primatology and Primate Center in Rome, who wasn't involved in the research, agrees.

"Veronika shows an egocentric form of tool use, that is the use of a tool toward herself. This kind of tool use is simpler than tool use toward an external object or surface for many reasons," she told Live Science via email. "One is that she directly perceives the effects of tool using on herself and then she can quickly correct and modify the position of the tool."

The findings represent the first documented case of tool use in cattle and use of a multi-purpose tool, Osuna-Mascaró said. The behavior can be partly explained by the fact that Veronika is kept as a family pet. She experiences different meadows and stables in the winter, and many objects fall into the meadow for her to interact with.

"Veronika was lucky to have the possibility to experience a day-a-day reality more complex and stimulating than the one usually offered to cows. Through the daily interaction between mind, body and environment, animals develop and improve their abilities and skills," Sabbatini said.

However, it doesn't mean this is a one-off. Osuna-Mascaró has also identified videos on social media of a Brahman bull (Bos indicus) using a stick to scratch an itch.

Given that the two species diverged more than 500,000 years ago and have been separately domesticated since, Osuna-Mascaró suggested that Veronica is showing a latent capability for innovation that could have been in cattle for thousands of years.

"We do not mean that ancient oxen were tool users, but that these animals have the capacity to innovate spontaneous solutions to complex problems," Auersperg said. "When they are little, cows play with objects, they love playing with balls, with ropes and also with sticks. So, if they have a rich environment, perhaps they will show these innovations more often."

Scientists have successfully extracted the DNA of ancient mummified cheetahs discovered in a cave in Saudi Arabia. This is the first time scientists have been able to extract genetic information from ancient naturally mummified big cats, researchers say, and it could lead to the animals' reintroduction to the region.

In 2022 and 2023, researchers discovered seven desiccated cheetahs and the skeletal remains of 54 others in the Lauga cave network the Arar area of northern Saudi Arabia. The remains date to between 100 and 4,000 years ago.

In a new study, published Thursday (Jan. 15) in the journal Communications Earth and Environment, scientists analyzed genetic data from the big cats and found that the older ones are most closely related to modern-day cheetahs in western Africa rather than Asian cheetahs.

Cheetahs (Acinonyx jubatus) are under threat globally. Populations have plummeted, and there are now only about 7,100 cheetahs left. The big cat, which is the world's fastest land mammal, once roamed through most of Africa and in Asia from the Arabian peninsula to India, but it now lives in about 9% of its historic range.

Today, there are five recognized sub-species of cheetah, four of which are in Africa and one (A. j. venaticus) in Asia. This Asian population is restricted to a small group of cheetahs in Iran.

No one is sure how many cheetahs once roamed in the Arabian peninsula, or how widely they were distributed. Similarly, there is little evidence about why or when they disappeared. Scholars speculate that it was a mixture of habitat loss and fragmentation, hunting and human-wildlife conflict.

However, the discovery of the hoard of ancient cheetah remains — which includes cubs and adults — proves that they once did roam the region — and could offer a blueprint for their return.

"The research provides strong evidence for the historical presence of cheetahs in Saudi Arabia and supports the potential for rewilding in this region to help expand their current range and restore part of their former distribution," Desire Dalton, a forensic scientist at Teesside University in the U.K., who studies the use of genomic tools to inform conservation and was not involved in the study, told Live Science.

In the study, researchers dated samples from two of the mummified cheetahs and five of the skeletons. The oldest skeletal remains belong to a cheetah that died about 4,000 years ago, while the two desiccated cheetahs are 130 and 1,870 years old respectively.

The team found evidence that prehistoric cheetahs in Saudi Arabia are genomically the closest to the West African A. j. hecki subspecies. Only the youngest specimen analyzed had closer links to the Asian subspecies A. j. Venaticus.

"Using advanced archaeological, radiological and genomic technique, the authors have established that the mummified cheetahs have two lineages," Kumarasamy Thangaraj, a forensic geneticist at the CSIR Centre for Cellular and Molecular Biology in Hyderabad, India, who was not involved in the study, told Live Science.

Dalton said that the identification of these unique lineages suggests that cheetah diversity loss may have been greater than scientists previously thought.

But the research gives conservationists a starting point to potentially reintroduce cheetahs to Saudi Arabia. The authors argue that cheetahs for rewilding in the Arabian peninsula can be sourced from the closest subspecies of the discovered cheetahs — A. j. Hecki — which is much more abundant than the Asian subspecies.

The DNA discovery could prove useful for ongoing rewilding efforts. In 2023, Saudi Arabia launched a program to reintroduce the Arabian cheetah. A year later, its National Center for Wildlife reported the birth of four cheetah cubs and the launch of its National Cheetah Conservation Strategy, which includes the creation of specialized breeding facilities, and the establishment of a wild breeding population.

The idea of using ancient DNA to reintroduce animals is not far-fetched, Dalton said. "Genetic studies have guided several successful rewilding projects." For example, genetic data for European bison (Bison bonasus) have informed breeding and translocation strategies for these animals. This reduced the risk of animals struggling to adapt to their new environment, she said. There is also a project underway to conduct ancient DNA analysis of European wolves (Canis lupus lupus) to develop targeted management strategies to preserve the biodiversity of European wolves, she said.

The study authors think that caves around the world could yield more secrets about ancient species. Caves in arid environments, such as Saudi Arabia, can generate hot, dry microclimates that are ideal for drying out animal remains, which can lead to mummification.

"The arid cave environments of Saudi Arabia, and elsewhere, may yet hold further important insights that can inform ecological histories, evolutionary insight, and actionable intelligence for rewilding and conservation," the authors wrote.

Scientists have analyzed the genome of a 14,400-year-old woolly rhino from a piece of its flesh found in the stomach of an ancient wolf pup. The results are giving experts insight into the woolly rhino's extinction, which probably happened rapidly due to climate change.

The woolly rhino (Coelodonta antiquitatis) tissue was found inside the mummified remains of a wolf pup, which was initially discovered in the Siberian permafrost in 2011. A subsequent necropsy of the pup revealed its final meal: It dined on one of the last woolly rhinos on Earth. But now, scientists have worked out how to sequence the animal's full genome from the undigested bits of rhino flesh.

"Sequencing the entire genome of an Ice Age animal found in the stomach of another animal has never been done before," Camilo Chacón-Duque, a bioinformatician at Uppsala University in Sweden and co-author of the new study, said in a statement.

In the new research, published Wednesday (Jan. 14) in the journal Genome Biology and Evolution, researchers analyzed the woolly rhino muscle tissue and compared it with older examples to investigate the species' population size and level of inbreeding just prior to its extinction. That chunk of meat has provided unprecedented information about the demise of the woolly rhino.

Many species that go extinct leave clues to their decline in their geographic range, their population size, and their genomes. As populations of an animal decrease, they can become concentrated in a particular area. For example, woolly mammoths (Mammuthus primigenius) persisted until about 4,000 years ago on a remote island in Siberia. But their small population contributed to inbreeding, and this lack of genetic diversity may have ultimately doomed the mammoth. (Although another study suggests that these island mammoths died in a random mystery event.)

The woolly rhino, however, was widespread across northern Eurasia until about 35,000 years ago. Its geographic range contracted over time, and the species became concentrated in northeastern Siberia, before going extinct around 14,000 years ago. The piece of woolly rhino tissue discovered in the wolf pup's stomach was carbon-dated to 14,400 years ago, meaning the woolly rhino was likely one of the last of its kind.

Researchers generated the woolly rhino's genome from the preserved muscle tissue and compared it with two older genomes dated to 18,000 and 49,000 years ago. They discovered that the three rhinos had similar levels of inbreeding and genetic diversity, suggesting that there was a relatively stable woolly rhino population in northern Siberia until at least 14,400 years ago, and that their extinction must have happened rapidly after that.

"Our results show that the woolly rhinos had a viable population for 15,000 years after the first humans arrived in northeastern Siberia, which suggests that climate warming, rather than human hunting, caused the extinction," study co-author Love Dalén, an evolutionary genomics professor at the Centre for Palaeogenetics in Sweden, said in the statement. The results build on previous work by several of the same researchers.

Rapid changes in the world's climate happened toward the end of the Pleistocene epoch (the last ice age), and many large mammals went extinct. The disappearance of the woolly rhino lines up with a period called the Bølling-Allerød interstadial, which involved an abrupt warming of the Northern Hemisphere's climate from around 14,700 to 12,900 years ago. This dramatically warmer climate may have wiped out the favored foods of the cold-adapted, herbivorous woolly rhino and thus contributed to their swift decline.

While the new genome does not resolve all the mysteries surrounding the extinction of the woolly rhino, the researchers demonstrated that it is possible to recover the DNA of one animal from inside another one.

"It was really exciting, but also very challenging, to extract a complete genome from such an unusual sample," study lead author Sólveig Guðjónsdóttir, a researcher at Stockholm University, said in the statement.

The researchers hope their achievement will pave the way for future DNA and genomic analysis of animal tissues from "unlikely sources."

Mammoth quiz: Test your knowledge of the ice age beasts

Of the more than 600 million cats across the globe, less than 10% belong to a specific breed. But are these purebred cats the result of human intervention, or did some develop naturally?

The answer is more complicated than it might seem. According to Leslie A. Lyons, a cat geneticist at the University of Missouri College of Veterinary Medicine, most cat breeds developed in the past 140 years as a result of human selection for specific physical traits.

However, a select few are known as "natural" cat breeds because they are derived from a population of cats that evolved due to factors in their natural environments over thousands of years. These natural cat breeds include some of the most beloved breeds today, such as Maine coons, Siberians, Russian blues, Norwegian forest cats, Turkish Vans and Egyptian maus.

According to Sarah Hartwell, a cat genetics hobbyist and founder of the cat resource MessyBeast, the progenitors of natural breeds form under the same conditions as wild species do.

"Natural breeds could be considered a step along the road to speciation," she told Live Science. In most cases, they form as a result of environmental adaptation. In Western Russia, cold and snowy conditions favored thick-furred, big-boned cats that became the foundation of the Siberian forest cat breed. In Southeast Asia and the coastal areas of the Indian Ocean, warm and humid conditions favored short-haired, slender-bodied, big-eared cats that set the stage for the Abyssinian.

In some cases, natural breeds begin as a result of geographic isolation. This phenomenon, known as the founder effect, occurs when a gene that is not advantageous to the animals' survival spreads because the population has a small, isolated gene pool. On the Isle of Man (a self-governing British Crown Dependency in the Irish Sea), a mutation that caused a short tail spread as a result of inbreeding, resulting in the ancestors of the Manx cat. Unfortunately, Manx cats can suffer from spinal defects due to this tail mutation.

Although the ancestors of natural breeds evolved under natural conditions, modern-day cats of these breeds are not so "natural" anymore.

"All breeds, no matter what species, have human influence," Lyons told Live Science. According to a study in the journal Animal Genetics that she co-authored, the selective breeding of cats has increased exponentially in the past century, which, in turn, has removed the environmental pressures that shaped natural breeds.

The Manx breed, for example, likely would have died out naturally due to a lack of genetic diversity and the detrimental effects of the short-tail mutation. In the modern day, the breed is still widespread as a result of intentional breeding by humans. However, there are some who are trying to eliminate it.

"The thought is to retire this breed, or find a way to make them healthier," Lyons told Live Science. "Maybe we [work toward] a tailed Manx."

Some of the once-natural breeds are more closely connected to their roots than others are. Modern Siberian cats, for example, are genetically and physically similar to their ancestors because breeders regularly bring in new cats, found as strays or as pets in the breed's home region, to add to breeding programs.

Other breeds have been altered both genetically and physically from their original appearance. Russian blues, for example, were crossbred with Siamese cats to prevent the breed's extinction after World War II, and breeders have since divided them into specific "types" that look different from the original cats.

So yes, "natural" cat breeds do exist, but they are not entirely natural. The traits that are quintessential of a Maine coon purchased from a breeder — such as large size, square jaw, and often feet with six or more toes — may resemble the Maine coons discovered back in the 1800s, but they have been preserved — and, in some cases, exaggerated — through artificial selection.

"It all depends on popularity and what people prefer," Lyons told Live Science. "One lineage of cats might become very popular and change what the breed looks like, and then it might swing back another direction depending on the next new craze."

Cat quiz: Can you get a purr-fect score?

One of my favorite activities is going to the zoo where I live in Knoxville when it first opens and the animals are most active. On one recent weekend, I headed to the chimpanzees first.

Their breakfast was still scattered around their enclosure for them to find. Ripley, one of the male chimpanzees, quickly gathered up some fruits and vegetables, sometimes using his feet almost like hands. After he ate, he used his feet to grab the fire hoses hanging around the enclosure and even held pieces of straw and other toys in his toes.

I found myself feeling a bit envious. Why can't people use our feet like this, quickly and easily grasping things with our toes just as easily as we do with our fingers?

I'm a biological anthropologist who studies the biomechanics of the modern human foot and ankle, using mechanical principles of movement to understand how forces affect the shape of our bodies and how humans have changed over time. Your muscles, brain and how human feet evolved all play a part in why you can't wiggle individual toes one by one.

Comparing humans to a close relative

Humans are primates, which means we belong to the same group of animals that includes apes like Riley the chimp. In fact, chimpanzees are our closest genetic relatives, sharing almost 98.8% of our DNA.

Evolution is part of the answer to why chimpanzees have such dexterous toes while ours seem much more clumsy.

Our very ancient ancestors probably moved around the way chimpanzees do, using both their arms and legs. But over time our lineage started walking on two legs. Human feet needed to change to help us stay balanced and to support our bodies as we walk upright. It became less important for our toes to move individually than to keep us from toppling over as we moved through the world in this new way.

Human hands became more important for things such as using tools, one of the hallmark skills of human beings. Over time, our fingers became better at moving on their own. People use their hands to do lots of things, such as drawing, texting or playing a musical instrument. Even typing this article is possible only because my fingers can make small, careful and controlled movements.

People's feet and hands evolved for different purposes.

Muscles that move your fingers or toes

Evolution brought these differences about by physically adapting our muscles, bones and tendons to better support walking and balance. Hands and feet have similar anatomy; both have five fingers or toes that are moved by muscles and tendons. The human foot contains 29 muscles that all work to help you walk and stay balanced when you stand. In comparison, a hand has 34 muscles.

Most of the muscles of your foot let you point your toes down, like when you stand on tiptoes, or lift them up, like when you walk on your heels. These muscles also help feet roll slightly inward or outward, which lets you keep your balance on uneven ground. All these movements work together to help you walk and run safely.

The big toe on each foot is special because it helps push your body forward when you walk and has extra muscles just for its movement. The other four toes don't have their own separate muscles. A few main muscles in the bottom of your foot and in your calf move all four toes at once. Because they share muscles, those toes can wiggle, but not very independently like your fingers can. The calf muscles also have long tendons that reach into the foot; they're better at keeping you steady and helping you walk than at making tiny, precise movements.

In contrast, six main muscle groups help move each finger. The fingers share these muscles, which sit mostly in the forearm and connect to the fingers by tendons. The thumb and pinky have extra muscles that let you grip and hold objects more easily. All of these muscles are specialized to allow careful, controlled movements, such as writing.

So, yes, I have more muscles dedicated to moving my fingers, but that is not the only reason I can't wiggle my toes one by one.

Divvying up brain power

You also need to look inside your brain to understand why toes and fingers work differently. Part of your brain called the motor cortex tells your body how to move. It's made of cells called neurons that act like tiny messengers, sending signals to the rest of your body.

Your motor cortex devotes many more neurons to controlling your fingers than your toes, so it can send much more detailed instructions to your fingers. Because of the way your motor cortex is organized, it takes more "brain power," meaning more signals and more activity, to move your fingers than your toes.

Even though you can't grab things with your feet like Ripley the chimp can, you can understand why.

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

Over the last three decades, Yellowstone National Park has undergone an ecological cascade. As elk numbers fell, aspen and willow trees thrived. This, in turn, allowed beaver numbers to increase, creating new habitats for fish and birds.

The shift has largely been attributed to the reintroduction of wolves to the park — as predators, they helped control the elk numbers. But their return may not have reshaped the entire ecosystem in the way that scientists thought, and has sparked a fierce debate among scientists over exactly why and how Yellowstone has rebounded.

According to a study published in January, the reintroduction of gray wolves (Canis lupus) in the 1990s created a trophic cascade — a chain reaction in the food web — that benefitted the entire ecosystem. The study linked wolves in the area to a reduction in the elk population, which in turn reduced browsing and allowed willow trees to grow. Between 2001 and 2020, this led to a 1,500% increase in crown volume, the total space filled by upper branches of the willows.

But now, scientists have written a response letter to the editor, published in Oct. 13 in the journal Global Ecology and Conservation, in which they argue that the original study's methodology was flawed, and that Yellowstone wolves' effect on willow shrubs is not so clear.

Large predators were targeted in Yellowstone from the end of the 1800s. By the 1920s, wolves were largely extinct from the park. Their disappearance created an ecological imbalance — the elk population exploded, which decimated plant populations and in turn threatened beavers, among other impacts. This is known as a trophic cascade, where the removal of one species causes ripples throughout the food web.

While the reintroduction of wolves to Yellowstone has led to changes within the park, the authors of the response letter claim the original study reinterpreted existing data to fit an oversimplified story.

The study converted willow height measurements collected and published by another research group into a metric called crown volume, response author Daniel MacNulty, a wildlife ecologist at Utah State University, told Live Science in an email. Crown volume was used as a proxy for willow size, meant to capture the shrub’s entire three-dimensional growth more than simply measuring its height.

"Because crown volume was built directly from height, [the study] only showed that height predicts height," MacNulty said. "They did not reveal anything new about how willow growth changed after wolf reintroduction."

The response letter suggests other inconsistencies in data analysis, like comparing willow measurements from different locations across years. This is problematic because it shows a misleading time series of willow growth, and MacNulty's research group has previously published research noting sampling biases in other studies supporting this same trophic cascade theory.

"There is substantial scientific evidence of a definitive effect of wolf recovery on the rest of the Yellowstone ecosystem," MacNulty said, like wolves increasing the supply of carrion to bears, coyotes, eagles and other meat-eating species. But the effect of wolves on vegetation is less clear because it operates through the decline of elk populations, which wolves were likely not solely responsible for. As MacNulty points out, humans, grizzly bears and cougars also hunt elk. "A major problem with the simple trophic cascade story is that it ignores the role of these other predators."

William Ripple, an Oregon State University wildlife ecologist and author of the original paper, stands by the original conclusions of the paper, maintaining that a large carnivore, elk, and willow trophic cascade occurred in Yellowstone. "Our methods are sound, the modeling approach is standard," Ripple told Live Science in an email. "So we reject the idea that there are fatal flaws."

The debate about Yellowstone wolves and the impact of their reintroduction goes beyond this study and the latest response. While scientists widely agree that there is a trophic cascade in Yellowstone, its strength — and which predators are most responsible for it — form the center of the disagreement, MacNulty said.

Some scientists argue the story is more complex. "There are reasons other than trophic cascades by which carnivores and plants can be positively associated," Jake Goheen, a wildlife ecologist at Iowa State University told Live Science in an email. Goheen, who was not involved in the research or response, said he doesn't believe that the authors of the original study provided enough evidence to support their conclusion that reintroducing wolves in Yellowstone caused a strong trophic cascade that affected willows.

"There is a growing body of literature at this point that has scrutinized the hypothesized cascade in Yellowstone," Goheen said. He adds that this does not mean there's no wolf-to-elk-to-willow trophic cascade in Yellowstone, only that the evidence presented so far is not clear enough.

To establish a clear trophic cascade from Yellowstone wolf reintroduction to willows, researchers would need to account for other predators and herbivores, said MacNulty. The ideal study would then analyze how much more total willow biomass there is now compared with before wolf introduction, to identify the strength of the effect; then calculate how much of that increase can be attributed solely to wolves, to identify its cause.

Ripple and his research team are now preparing a detailed reply, which explains that criticisms of the original study come from misunderstandings of what they did, Ripple said. "The basic scientific logic of the paper is solid," Ripple said.

Conservation priorities might be fueling the controversy over large carnivores' beneficial effects on ecosystems, said Goheen, adding that even if wolves are not definitively causing a trophic cascade to willows, they are still important to conserve.

Primates — the mammalian group that includes humans — are found pretty much everywhere on Earth, from equatorial rainforests to scientific research stations in Antarctica. This hugely diverse order appeared before the dinosaurs went extinct, with wild populations of non-human primates evolving to live in niches across three continents — Asia, Africa and Central/South America.

Primates don't just live in lots of places; there are also hundreds of species and subspecies. In fact, the order primates is the fourth most biodiverse mammal order in the animal kingdom — yet the majority (62.6%) of primates are threatened with extinction.

Scientists researching primates, called "primatologists," have learned a lot over the years about our closest evolutionary relatives. For example, did you know that chimps have opposable big toes, or that not all monkeys can swing through the trees? Or even that there are some primates that are neither monkeys nor apes?

Fancy yourself a primatologist? Put your knowledge to the test below!

Remember to log in to put your name on the leaderboard; hints are available if you click the yellow button. Good luck!

More science quizzes

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In late December 1985, a worker opened the door to a remote cabin in the Virunga Mountains of Rwanda and encountered a horrific scene: Gorilla researcher Dian Fossey, whose aggressive approach to conservation had pitted her against the local community, had been hacked to death with a machete, and her cabin had been ransacked.

Fossey had been working with an endangered gorilla population in Rwanda's Volcanoes National Park since the late 1960s. Along with Jane Goodall and Biruté Galdikas, she was one of the three "trimates" chosen by Louis Leakey to study primates in their natural habitat.

Fossey had no formal training in ethology, the science of animal behavior, when she set out for Africa. She began her field work in Kabara, Congo, living in a tiny tent and venturing out to study mountain gorillas (Gorilla beringei beringei) there. After civil war broke out in 1967, she escaped to the Rwandan portion of the mountains and set up a new research project near Mount Karisimbi in Rwanda.

Fossey was inspired by the work of George Schaller, a biologist who, in 1959, had also studied the gorillas of the Virunga Mountains.

"I knew that animals try to stay out of your way. If you go quietly near them, they come to accept your presence. That's what I did with gorillas. I just went near them day after day, which was fairly easy because they form cohesive social groups. Soon, I knew them as individuals, both their faces and their behavior, and I just sat and watched them," Schaller said in a 2006 interview.

Fossey operated on this same principle of patient, unobtrusive observation. Still, the gorillas initially fled from her, and she spent hours tracking and trailing them across the misty forest.

After a year, they stopped fleeing at her presence and started beating their chests and vocalizing. It was a bluff meant to scare her off, but it was still far from their ordinary, natural behavior, she said in a 1973 lecture. After two years, she received two young gorillas, Coco and Pucker; rehabilitated them; and learned about gorilla young by observing them.

"I came to know the gorillas' need for love and affection, and the young gorillas' need for constant play," she said.

It would take three years before the gorillas came to accept her presence and reveal more naturalistic behavior, she said in the lecture.

During her decades in Virunga, Fossey described and learned to mimic the vocalizations of gorillas, including the "belch vocalization" that signifies contentment. She also elucidated their tight-knit family structures, courtship and mating rituals, as well as documented the occasional murder of infant gorillas by rival males.

Although she would eventually earn her doctorate in zoology from the University of Cambridge, Fossey spent her first years studying the gorillas with no formal training. Perhaps because of her initial lack of training, she formed close bonds with individual animals and tended to ascribe more humanlike motivations and descriptions to their actions than is typically accepted in formal zoology. She often described gorillas as more altruistic than humans.

"You take these fine, regal animals,'' she told an interviewer, as reported by The New York Times. ''How many fathers have the same sense of paternity? How many human mothers are more caring? The family structure is unbelievably strong.''

She formed a particularly close bond with a gorilla she nicknamed Digit — so named for his damaged finger — who did not have playmates his age. Digit was killed by poachers in 1977.

The last years of Fossey's life were increasingly focused on conserving the gorillas' dwindling habitat and combating poachers. She used confrontational methods, such as burning snares, wearing masks to scare poachers, and spray-painting cattle to prevent herders from bringing them into the national park, according to the Dian Fossey Gorilla Fund.

She also shot over the heads of tourists to scare them away and told her graduate students to carry guns, according to The Washington Post.

Given that many of the people living on the fringes of the park lived in poverty and resorted to expansion and herding to survive, this did not earn her good will with many of the locals.

Fossey's murder was never solved. Many think poachers were responsible for the killing, but other theories have been floated as well.

Over 10,000 years of domestication, cats have learned to meow to get exactly what they want from their human servants. Now, researchers in Turkey have found that cats greet men far more vocally than they do women — and this could be another way they manipulate us to get the attention they deserve.

The new research reveals "cats' ability to categorize bonded individuals and modulate their responses," said study co-author Kaan Kerman, principal investigator of the Animal Behavior and Human-animal Interactions Research Group at Bilkent University in Turkey. "This shows that cats are not automata and possess cognitive abilities that enable them to live alongside humans in an adaptive manner," he told Live Science in an email.

Despite their reputation for being aloof and unfriendly, cats are actually highly communicative and masters at fitting into different social groups.

"Both the public imagination and the scientific community for a time viewed cats as loners with little need for social bonds," Kerman said. However, "cats are more social than previously assumed. They do not interact with humans solely to obtain food. They actively seek social contact and form bonds with their caregivers."

Greeting is a key part of that sociability, as it helps reinforce bonds between domestic cats (Felis catus) and their humans, the researchers wrote in the study, which was published Nov. 14 in the journal Ethology.

To find out more about how cats greet humans, the researchers fitted 40 cat owners with cameras. They were asked to film the first 100 seconds of their interactions with their cat after returning home. The participants were told to act normally so they could capture typical interactions. The researchers then analyzed the footage to assess whether certain behaviors are related, and whether different demographic variables influenced the cats' behaviors.

Nine people were excluded from the study for various reasons, but videos from the remaining 31 participants revealed that the cats were far more vocal toward men than women when their humans first walked in. "No other demographic factor had a discernible effect on the frequency or duration of greetings," the researchers wrote.

The researchers then accounted for different factors, such as the animals' sex, pedigree status and number of cats in the household — but found that the sex of the human was the only significant influence on cat vocalizations.

The researchers suggest this could be because women are typically more verbally active with their cats and better at interpreting what their cats want. Men, on the other hand, may need a lot more prompting before they pay sufficient attention to their cats, the researchers hypothesized in the study.

The team also speculate that cultural factors may have influenced their findings. Previous research shows that people in different cultures interact with cats in different ways — and that this also impacts how cats interact with humans. In this case, the participants were in Turkey, and it may be that men in Turkey are less likely to be chatty with their cats, the team wrote. "However, this interpretation remains speculative and warrants further exploration in future research," the team wrote.

The team also found that meowing and other vocalizations didn't fit into a specific pattern of behavior — meaning these vocalizations were not a sign of a specific emotional state or need.

The team acknowledged that the study has several limitations, including the small sample size and the participants being from the same region. The researchers also noted that the study did not control for other potentially important factors, such as how hungry the cats were when their humans returned, the number of other people in the household or the length of time the animals were alone. Previous research suggested that cats react differently to humans — such as by purring and stretching more — when they are separated for longer periods of time, so the results don't necessarily reveal that cats always meow more at men.

"One important next step is to replicate the findings in different cultural contexts. This would help us understand how generalizable the results are," Kerman said.

Dennis Turner, director of the Institute for Applied Ethology and Animal Psychology in Switzerland who was not involved in the study, said he was impressed by the team's findings.

"I liked the authors' speculation about the reason for this finding and suspect that the men either were less attentive to the cats' vocalizations on other occasions or reacted differently (more or less strongly, different voice frequency) to the greeting vocalizations than women," he told Live Science in an email.

"Much of my team's research [h]as shown that men and women (and children) interact differently with cats in the household." For instance, women speak more to cats and are likelier to go down to the cats' level to interact with them, he noted.

However, cats likely have no preference towards men or women, Turner added. Instead, he agreed with the researchers' view that more meowing toward men is a sign of cats' social flexibility.

Cat quiz: Can you get a purr-fect score?

Pumas in Patagonia are preying on penguins — and it's changing how the big cats interact with each other.

The pumas in question reestablished themselves in an Argentinian national park that housed a penguin breeding colony — and the cats promptly began eating the birds. Now, it turns out the normally solitary cats that eat the penguins are tolerating each other more often than expected, new research published Wednesday (Dec. 17) in the Proceedings of the Royal Society B reports.

The findings suggest that reintroductions like these can have surprising knock-on effects.

"Restoring wildlife in today's changed landscapes doesn't simply rewind ecosystems to the past," said study co-author Mitchell Serota, an ecologist at Duke Farms in New Jersey. "It can create entirely new interactions that reshape animal behavior and populations in unexpected ways."

Sheep ranchers in Patagonia forced pumas out of the region in the 20th century. After Monte Leon National Park was established in 2004, pumas have started making their way back. But in the pumas' absence, other species had adapted to the reduced hunting pressure. For example, a group of Magellanic penguins (Spheniscus magellanicus), usually confined to offshore islands, established a mainland breeding colony consisting of some 40,000 breeding pairs.

Shortly after the park was established, researchers started noticing penguin remains in puma scat. The pumas were taking advantage of the changed ecosystem.

"We thought it was just a couple individuals that were doing this," said Serota, who conducted the research while he was a doctoral student at the University of California, Berkeley. "But when we got there … we noticed a ton of puma detections near the penguin colony."

In the new study, researchers used cameras to estimate how many pumas lived near the penguin breeding colony, a 1.2 mile (2 kilometers) stretch of beach inside the national park. They also tracked 14 individual pumas with GPS collars and investigated penguin kill sites across several field seasons between 2019 and 2023. Nine of the pumas they tracked hunted penguins, while five did not.

Pumas that ate penguins had bigger variation in their ranges from season to season, the study found. The penguin-eating cats stuck close to the penguin colony when the birds were in the national park during breeding season. But they ranged about twice as far when the birds migrated offshore during the summer.

Penguin-eating pumas also interacted with each other more often than pumas who relied on other prey. The researchers documented 254 encounters between any two of the pumas who both ate penguins, and just four encounters between pumas where neither ate penguins. Most meetings between pumas occurred within 0.6 miles (1 km) of the penguin colony.

Because multiple pumas were using the colony as a food source, this disparity suggests that penguin-eating pumas tolerate other pumas better than those that rely on other prey, likely because they don't have to compete as much for the plentiful food. In fact, the researchers found that the density of pumas within the park was more than twice the highest previously-recorded concentration within Argentina. Usually, adult pumas are solitary and establish large ranges to ensure they have enough prey to feed themselves and their kittens.

Understanding how large carnivores behave when they return to ecosystems impacted by humans "is essential for conservation planning because it allows managers to … design management strategies that are grounded in how ecosystems actually function today, not how we assume they should function based on the past," Juan Ignacio Zanon Martinez, a population ecologist at Argentina's National Scientific and Technical Research Council (CONICET) who was not involved in the study, wrote in an email to Live Science.

Knowing how the pumas' behavior affects both the cats and the penguins could aid future conservation efforts in the park.

For example, puma predation might not have a big effect on large breeding colonies, but it could affect the growth of new, smaller colonies. It's a "complex situation for the people who do the management of the area, because you have two native [species] interacting," in a way that's different from before human activities changed the ecosystem, said Javier Ciancio, a biologist at CONICET who was not involved in the new study.

In future work, Serota says the team will investigate how the relationship between pumas and penguins affects pumas' other prey, such as the guanaco (Lama guanicoe), a relative of the llama.

Temperature stress may be driving genetic mutations in polar bears in southern Greenland, a new study reports.

The species is struggling in the face of a changing global climate. Global sea ice levels dropped to a record low in February, and the warming planet is pushing up sea levels. These changes threaten polar bears, which live and hunt on the shrinking ice sheets.

But a group of polar bears (Ursus maritimus) in southern Greenland may be evolving to cope with their challenging environment. Researchers have found a link between changes in polar bear DNA and rising temperatures.

The study, published Dec. 12 in the journal Mobile DNA, "shows, for the first time, that a unique group of polar bears in the warmest part of Greenland are using 'jumping genes' to rapidly rewrite their own DNA, which might be a desperate survival mechanism against melting sea ice," lead author Alice Godden, a senior research associate at the University of Anglia in the U.K., said in a statement.

Jumping genes, also known as transposons or transposable elements, are pieces of DNA that move from one location on the genome to another. Depending on where they insert themselves into the organism's genetic code, transposons can change how other genes are expressed. More than one-third of the polar bear genome is made up of transposable elements, while in plants it can be as much as 70%. By contrast, transposons make up about 45% of the human genome.

Transposons appear to be helping polar bears adapt to climate change, the authors of the new study argue.

A 2022 study published in journal Science described an isolated population of polar bears in southern Greenland that was less reliant on sea ice. The group split from a community of bears in northern Greenland about 200 years ago, and their DNA was different from that of bears in the North. The new research builds on these earlier findings.

The researchers analyzed the DNA of 17 adult polar bears in Greenland — 12 from the cooler northeast and five from the group in the warmer southeast. They compared transposon activity in the two populations, and then linked that with climate data.

In the Southeastern population, there were changes to genes linked to heat stress, aging, and metabolism, as well as fat processing, which is important when food is scarce. According to the study, this suggests the bears "might be adjusting to their warmer conditions."

"By comparing these bears' active genes to local climate data, we found that rising temperatures appear to be driving a dramatic increase in the activity of jumping genes within the southeastern Greenland bears' DNA," Godden said. "Essentially this means that different groups of bears are having different sections of their DNA changed at different rates, and this activity seems linked to their specific environment and climate."

Despite the bears' potential ability to adapt to warmer climates and less ice, Godden warned that climate change remains a real threat to polar bears.

"We cannot be complacent; this offers some hope but does not mean that polar bears are at any less risk of extinction," she said. "We still need to be doing everything we can to reduce global carbon emissions and slow temperature increases."

Humans were living alongside leopard cats in settlements in ancient China more than 3,500 years before domestic cats arrived, new research shows.

The findings reveal that people in the region had an enduring and complex relationship with such animals for thousands of years before domestic cats arrived with merchants along the Silk Road 1,400 years ago.

"Now, they [leopard cats] are our hidden neighbors, but thousands of years ago they lived in a closer relationship with people," study co-author Shu-Jin Luo, principal investigator at Peking University's School of Life Sciences in Beijing, China, told Live Science.

The work was published Thursday (Nov. 27) in the journal Cell Genomics.

Modern domestic cats (Felis catus), which are descended from African wildcats (Felis lybica), have adapted so successfully to living with humans that they are now found on every continent except for Antarctica.

Yet when and where they were originally domesticated is uncertain, with researchers previously suggesting the Levant 9,500 years ago and Egypt about 3,500 years ago. One of the main hypotheses is that they spread to Europe with Neolithic farmers about 2,500 years ago and then were eventually taken along the Silk Road through Eurasia into China.

However, in 2013, evidence of cats living alongside humans in western China thousands of years before that, in about 3300 B.C., came to light, casting doubt on that idea.

In 2022, analysis of the cat DNA revealed that these ancient cats in China weren't domestic cats but were leopard cats (Prionailurus bengalensis), a small wild cat native to South, Southeast and East Asia.

Rather than clearing everything up, the result led to more questions: how long the leopard cats had lived alongside humans, when and how domestic cats reached China, and what drama played out when the domestic cats turned up and found that they weren't the only felid in town.

To find out more, researchers behind the new study used radiocarbon dating and DNA sequencing of nuclear and mitochondrial genomes from samples of 22 ancient felid bones, which were unearthed in 14 archaeological sites across China dating from about 3500 B.C. to A.D. 1800. The scientists then compared their results with previously published ancient and modern cat genomes from around the world.

Of the 22 individuals, 14, dated to between about A.D. 730 and 1800, were domestic cats. The earliest domestic cat was excavated from Tongwan City, a key hub along the Silk Road in western China. Previous research identified another domestic cat farther west along the Silk Road in Kazakhstan, dated to between A.D. 775 and 940.

The earliest known depictions of domestic cats in China are painted motifs in two tombs in central China dating to about A.D. 820 and 830, and there is also a written account from about the same time of the empress presenting a pet cat to her ministers.

These records hint that domestic cats arrived in China via the Silk Road relatively recently, in about A.D. 700, and as a recent introduction were thought of as exotic pets and likely kept among the ancient Chinese elite, Luo told Live Science. The cats were often white, which was considered a sacred color in animals, she said.

All the earlier remains belonged to leopard cats, dating from between about 5,400 years ago to approximately A.D. 150.

When the researchers studied the cats, they realized that the close relationship between humans and leopard cats was not a transient and occasional thing but instead a shared history lasting for over 3,500 years, Luo said.

She added that leopard cats in ancient China may have once occupied a similar niche to domestic cats, entering a commensal relationship with humans by preying on small rodents in villages and fields.

"I think in ancient times, people would keep the cub and try to raise it so they can catch rodents. I don't think it's ever been fully domesticated, but it was definitely a more intimate relationship than with today's leopard cat," Luo said.

Eva-Maria Geigl, a paleogeneticist at the Jacques Monod Institute of the French National Centre for Scientific Research (CNRS) who wasn't involved in the study, told Live Science the findings reflect the domestication process of cats around the Mediterranean. "It's a commensal relationship, taking advantage of the human niche and this was very welcomed by the Neolithic farmers as they really had to struggle with the rodents and with venomous animals," she told Live Science. "Such cats were not domesticated in the sense as we see it now — these couch potatoes — they were real wild cats still."

Records compiled between the fifth and third centuries B.C in China provide further evidence of this relationship, Luo said, indicating that people welcomed wild cats on their farms for pest control. This means leopard cats may have had a relationship with humans that lasted approximately 3,500 years, she said.

However, this relationship eventually ended, and there is a nearly 600-year gap between the last uncovered leopard cats and the earliest appearance of domestic cats in China.

Luo said this lack of cats coincides with the Period of Division (A.D. 220 to 589) after the collapse of the Han dynasty and before the rise of the Tang dynasty. It was a time of war and colder, drier conditions with declining agricultural yields, social unrest and a shrinking population. A similar temporary population decline was seen in black rats (Rattus rattus) in Europe after the fall of the Roman Empire.

This means the leopard cats likely lost their hunting grounds, Luo said. When the Tang dynasty was established in A.D. 618, and agriculture and the human population rebounded, the leopard cats were no longer so welcome, because of the rise of keeping chickens.

Leopard cats still have a bad reputation for killing chickens, she said, so the cats would have become unwelcome animals. In southern parts of China, the leopard cat has the nickname the "chicken-killing tiger," Luo said.

Domestic cats took their place because they are cute, tame and generally catch smaller prey like mice and rats, not chickens, Luo suggested.

Geigl said the crucial shift that led domestic cats to gain widespread acceptance probably came in Egypt in the first millennium B.C., when people bred cats in temples and fed many cats together, and a genetic mutation led to behavioral change. "This is not normal behavior for a cat. A cat is a territorial solitary animal, just the opposite of what the Egyptians had," she noted.

Cat quiz: Can you get a purr-fect score?

Most modern dog breeds have small amounts of wolf ancestry from long after dogs were domesticated, according to a new study.

The wolf DNA isn't left over from when dogs and wolves diverged; instead, it most likely came from interbreeding in the past few thousand years. That wolfish influence may be linked to certain characteristics, such as size and personality traits, in different dog breeds, researchers reported Nov. 24 in the journal PNAS.

"Dogs are our buddies, but apparently wolves have been a big part of shaping them into the companions we know and love today," study co-author Logan Kistler, curator of archaeobotany and archaeogenomics at the Smithsonian National Museum of Natural History in Washington, D.C., said in a statement.

Wolves and dogs genetically split more than 20,000 years ago. Since then, there has been some gene flow between dogs and wolves, thanks to their genetic compatibility. To measure the extent of intermixing and its effects on both animals, researchers studied the previously published genomes of nearly 2,700 dogs and wolves from the Late Pleistocene (the last ice age) to the present. This group included 146 ancient dogs and wolves, 1,872 modern dogs and about 300 "village dogs" that lived around humans but weren't pets.

At least 264 modern dog breeds have wolf ancestry passed on from mating that occurred an average of 900 dog generations ago, which equates to about 2,600 years ago — long after dogs became domesticated at least 20,000 years ago, the team found. The most wolfish dogs had up to 40% wolf ancestry in their genomes, but most had between zero and 5% wolf ancestry.

"Prior to this study, the leading science seemed to suggest that in order for a dog to be a dog, there can't be very much wolf DNA present, if any," study co-author Audrey Lin, an evolutionary biologist at the American Museum of Natural History in New York City, said in the statement. "But we found if you look very closely in modern dog genomes, wolf is there. This suggests that dog genomes can "tolerate" wolf DNA up to an unknown level and still remain the dogs we know and love."

Czechoslovakian and Saarloos wolfdogs had the highest degree of wolf ancestry, which is perhaps unsurprising, since they were intentionally bred by crossing domestic dogs with wolves in the 20th century. Larger dogs and certain working breeds — such as Arctic sled dogs, hunting dogs and certain guardian dog breeds from west and Central Asia, such as Anatolian shepherds — tended to have higher levels of wolf ancestry.

But plenty of breeds didn't fit these patterns. Some large guardian dogs, such as bullmastiffs and Saint Bernards, didn't have any detectable wolf ancestry. And some smaller dogs had small amounts of wolfish DNA. For instance, 0.2% of the Chihuahua's genome can be traced back to wolves, the team found.

"This completely makes sense to anyone who owns a Chihuahua," Lin said in the statement. "And what we've found is that this is the norm — most dogs are a little bit wolfy."

Meanwhile, every tested "village dog" had wolf DNA in its genome, the scientists found. And the reason why might be related to their survival. "The stretches of wolf DNA we found in village dog genomes contained genes related to olfactory receptors," Lin and Kistler wrote in The Conversation. "We imagine that olfactory abilities influenced by wolf genes may have helped these free-living dogs survive in harsh, volatile environments."

Some personality traits that kennel clubs use to describe certain breeds also tracked with the amount of wolfish influence. Breeds with lower wolf ancestry were frequently described as "friendly," "easy to train" or "lively," while breeds with more wolf DNA were pegged as "suspicious of strangers," "independent" and "dignified." It's not yet clear if wolf genes are directly responsible for these traits.

Footage of a hungry wolf performing a complex sequence of behaviors on the coast of British Columbia could potentially mark the first case of tool use in wild canids.

The wolf swam into deep water to retrieve a floating buoy attached to a submerged crab trap. It couldn't see the crab trap, but seemed to know the trap was there and how the human tool worked — once back on shore, the wolf began to reel in the line that led to the trap, scientists explained in a new research paper. Finally, when the trap emerged from the water, the wolf broke it open and devoured the bait inside.

Wolves (Canis lupus) have been recorded interacting with human objects before, but this behavior was much more sophisticated than anything previously documented in these animals, according to the study, which was published Nov. 17 in the journal Ecology and Evolution.

"This is a new dimension of wolf behaviour we had not seen before," study lead author Kyle Artelle, an assistant professor at the State University of New York College of Environmental Science and Forestry, told Live Science in an email. "It shows how we have likely only scratched the surface of what the other species we share this world with can do, what and how they think, and what they can teach us."

The bait-snatching wolf lives within the Indigenous Haíɫzaqv Nation Territory on the central coast of British Columbia. These wolves spend a lot of time on the coast, with many relying on the sea for their food, according to the Haíɫzaqv Wolf and Biodiversity Project, which was responsible for the new research and which Artelle helps coordinate.

The new behavior was spotted because Haíɫzaqv Guardians, Indigenous people who conduct research and monitoring on behalf of their nation and the project, kept finding their crab traps damaged by an unknown predator. The crab traps are part of an attempt to eradicate invasive European green crabs (Carcinus maenas), which outcompete native crabs and generally disrupt Canada's marine ecosystems, so it's important for the traps to remain intact.

Initially, it was suspected that seals, sea lions or otters may have been responsible for the damage. A lot of the traps are placed in deep water and don't get exposed even at low tide, so it seemed likely that the culprit was a marine animal. However, within a day of the researchers deploying camera traps in May 2024 in attempts to identify the culprit, the wolf was caught red-pawed.

Wolves have long had a reputation for being smart, but this footage could be the best example yet of their cognitive prowess, the researchers said.

"We realized this was important on the first watching," Artelle said. "Folks who know wolves well have always recognized how intelligent they are, but here is a video that really speaks for itself, that really highlights this clever behaviour, and shows us another aspect of the kinds of behaviours they can exhibit that we had not seen before."

The wolf's seemingly advanced intellect might not come as a surprise to owners of their domesticated pet cousins. Sophisticated behavior is well documented in dogs (Canis lupus familiaris), helped by the fact that we spend so much time with them. Researchers have even compared some dog behaviors, like learning the meaning of human words and gestures, to those of our famously quick-witted relatives, chimpanzees (Pan troglodytes), according to the study.

Researchers have also considered that dogs may be tool users, evidenced by behaviors such as moving chairs to [then jump on to in order to] access food. The same is potentially true for dingos, which have similarly been observed manipulating furniture in captivity. However, the authors couldn't find any reported tool use by a canid (member of the dog and wolf family) in the wild, which could make the wolf's clever feat the first case of wolf tool use captured on camera.

Tool use was once considered a unique trait of human intelligence. However, scientists have steadily dismantled this idea by documenting various nonhuman animals — including chimpanzees, capuchin monkeys and New Caledonian crows (Corvus moneduloides) — using tools. Of course, plenty of animals don't need to use tools, so the behavior is not necessarily the most reliable indicator of superior intelligence.

Precisely what constitutes tool use is debated among scientists, which muddies the new findings. Researchers generally accept that tool use involves the manipulation of an external object to achieve a specific goal with intent. However, some behaviors, like the pulling of a rope, can be excluded from definitions when the animals aren't deemed responsible for the rope's orientation, according to the study.

The wolf's use of a line to retrieve crab traps might be complex enough to be an exception to some researchers' rope exclusion rule. The problem is that the authors of the new study aren't sure what mechanisms are driving this newly observed behavior.

While the wolf appeared to have a sophisticated understanding of the unseen trap and its connection to the floating buoy above — potentially stemming from watching the Haíɫzaqv Guardians interact with the traps — the study doesn't rule out that the animals used a much simpler cognitive process: trial and error.

The camera traps, which are now a permanent feature in the Haíɫzaqv crab-hunting areas, have yet to capture a second incident of a wolf hauling up submerged bait. However, the researchers did retrieve some earlier clips that suggest one camera got tantalizingly close. The camera's footage opens with a dark wolf walking toward an exposed crab line that disappears off-screen. Once the wolf is out of shot, the line wobbles, and the next time the camera is triggered, the wolf is seen investigating the bait cups of two traps that have somehow made it to shore.

Killing neighbours and taking over their lands led to a baby boom for a chimpanzee community in Uganda — potentially showing why it can be advantageous for chimps to start wars.

Chimpanzees (Pan troglodytes) have long been known for violent conflict or "warfare." It was first documented by English primate researcher Jane Goodall, who in 1974 observed the chimpanzee community in Gombe National Park in Tanzania splinter into two warring groups, leading to a four-year battle that resulted in the deaths of all the males in one group. But why the animals persisted with the violence for so long wasn't clear.

To shed light on this, the lead author of a new study Brian Wood, an anthropologist at the University of California, Los Angeles, and his colleagues examined data collected on chimpanzees in Kibale National Park in southwestern Uganda over more than three decades.

Between 1998 and 2008, the Ngogo chimpanzees of Kibale engaged in violent clashes with their neighbors. During this decade of conflict, at least 21 chimpanzees from neighboring groups were killed, and in 2009, the Ngogo chimpanzees expanded into an area previously inhabited by their rivals, boosting their territory by 2.5 square miles (6.4 square kilometres) or 22%.

The records revealed that in the three years before the territorial expansion, the female Ngogo chimps gave birth to 15 offspring. But in the three years after it, they gave birth to 37 youngsters, more than doubling their fertility rate.

What's more, the infants born after the expansion were more likely to survive: they went from having a 41% chance of dying before the age of 3 to just an 8% chance of it. The study was published Nov. 17 in the journal PNAS.

"At the time, it was very obvious to the field workers that the chimpanzees were experiencing a baby boom. We expected to see that in the data, but not the boost to survivorship," Wood told Live Science.

The work provides the best evidence yet that, for chimpanzees, expanding territory after killing off rivals can directly boost reproductive success, he said. The chimpanzees’ territorial expansion gave them access to more food, and the subsequent improvement in nutrition and health probably led to higher female fertility and better survival rates among the young, Wood added.

The boost to survival rates could come down to two factors. The first, Wood said, is an improvement in the health and energy of the mothers, and the other the removal of rival males.

"The survival being higher makes sense because a major source of mortality for chimpanzee babies is getting killed by their neighbours," Michael Wilson, who studies the behavior and biology of chimpanzees at the University of Minnesota and wasn't involved in the study, told Live Science. "What this study supports is the idea that under certain conditions, it is adaptive to defend group resources and kill members of neighbouring groups. The chimpanzees are looking out for their own group, essentially."

Yet, if there is a benefit for the winners, there will be a cost to the losers, Wood said. He thinks it is likely to be a zero-sum game and there would probably be no overall gain in chimpanzee numbers because while the victors benefit, others lose.

The scientists behind the study claim that the findings could help shed light on the evolution of violence in humans. Because there is lethal violence in our closest living relatives — chimpanzees and bonobos (Pan paniscus) — some scientists have previously suggested this trait may have been present in our shared common ancestor, which probably lived six or seven million years ago, Wood said.

Competition over access to land and resources is still an ever-present part of the human condition, he said, but it is generally transformed by the human ability to mediate and avoid conflict.

"Ongoing conflict in the world over resources has echoes of what chimps are up to, but I don't think that's a favourable comparison if you happen to be involved," Wood said.

In general, there's a striking difference between humans and chimpanzees when it comes to intergroup relations, Wilson said. "If a chimpanzee sees a male from a neighbouring group, the only way he can benefit is by imposing some cost on that male, taking his territory or taking his life."

When people see a stranger from another group, there is a chance that they can benefit from interacting with them, he said.

It is this that has allowed humans to create multi-level societies with ties of trade, kinship and ritual forming larger units of social organization.

"In the modern world, the benefits from intergroup interactions have grown so enormous and the costs of war have also multiplied so enormously that it's generally a pretty dumb idea to start a war," Wilson said.

If you've ever seen a litter of kittens, you may know that many of them barely look related. With coats ranging from black to white, tortoiseshell to tabby, and even long-haired to short-haired, littermates can look quite different from each other.

So why do kittens often not resemble their close relations, whereas most human siblings look similar to each other? The answer comes down to the complicated nature of cat coat genetics and a phenomenon in cat ovulation.

The genetics of cat coat color

The Cat Fanciers' Association recognizes dozens of coat colors and patterns, including everything from basic solid colors to more distinctive patterns, like the Bengal's rosetted tabby coat or the Abyssinian's ticked fur. All of those variations stem from a complex system of interacting genes.

"There are a number of different genes involved in cat color and pattern, and it's particularly complicated because some genes overwrite other genes," Jonathan Losos, a professor of biology at Washington University in St. Louis and author of "The Cat's Meow: How Cats Evolved from the Savanna to Your Sofa" (Viking, 2023), told Live Science.

Different genes control solid coat colors, spotting, patterns and hair length. According to Losos, these genes come in a "hierarchy" — for example, one gene mutation for white fur, called dominant white, will override any other colors. Other genes control patterns such as tabby fur, and these work in combination with genes for color to produce a coat. Some cat coat colors are also sex-linked, meaning the gene is contained on the X chromosome, so the range of colors and patterns for male and female cats is different. In general, only female cats have calico or tortoiseshell patterns.

If all of these gene variations are hard to keep track of, that's the point. Even a few different combinations of a handful of genes can have drastically different outcomes for coat color, pattern and length, and that's one big reason cat littermates can look so different even when they have most of the same genes. But there's another factor that makes the genetics of cat litters even more complicated.

Multiple paternity

Female cats are induced ovulators, which means their reproductive system doesn't release eggs until they've already mated with a male. This increases the chance of successful fertilization, but it also comes with a catch: The female can release multiple eggs during this time, so if she mates with another tomcat in the next few days, she can become pregnant by multiple males.

That means kittens in the same litter can have more than one father, so some siblings are only 25% genetically related to each other, leaving a lot more room for variation in their appearance. This phenomenon is called heteropaternal superfecundation, and it's actually not that rare in the animal kingdom; dogs, sheep and cows can also have multiple births with more than one father. In extremely rare cases, heteropaternal superfecundation has even been documented in humans.

"I don't think it's unusual that cats do this," Losos said.

Scientists don't know exactly why heteropaternal superfecundation is so common in cats, but there are theories.

For one, induced ovulation could be a more resourceful way to go about mating, and heteropaternal superfecundation is a side effect of induced ovulation. "It might be an evolutionary adaptation that allows the mating process to be more efficient," Bruce Kornreich, director of the Cornell Feline Health Center, told Live Science. He explained that releasing eggs only after mating prevents eggs from being "wasted" so that the female cat's reproductive system doesn't use energy on unneeded eggs.

Multiple paternity within a litter could even have its own advantages, Losos noted. When littermates have different fathers, it increases the genetic diversity of cat families, which is generally good for survival.

Heteropaternal superfecundation is much more likely to occur in urban areas, where the concentration of cats is high and tomcat territories are likely to overlap. In fact, one 1999 study found that 70% to 83% of urban cat litters had more than one father, whereas only zero to 22% of rural litters had more than one father, making diverse litters the norm rather than the exception.

Cat quiz: Can you get a purr-fect score?

Scientists have discovered a new type of lion roar — the intermediate roar — which is shorter and lower-pitched than the animal's iconic, full-throated roar.

The researchers found that these intermediate roars always follow full-throated roars. The discovery reveals that lion vocalizations are more complex than previously thought, said study lead author Jonathan Growcott, a doctoral student in mathematics and statistics at the University of Exeter in the U.K.

"The full-throated roar is an explosion of sound. Loud and complex and arcs in pitch," Growcott told Live Science in an email. "The intermediary roar differs by being a flatter sound with less variation."

The discovery, published Friday (Nov. 21) in the journal Ecology and Evolution, challenges the long-held belief that there is only one kind of lion roar, and it could help researchers estimate lion population sizes more accurately, he said.

Lions roar to communicate with their pride and establish their territory. Previous research has indicated that lions' full-throated roars are unique, individually identifiable signatures that contain information about an animal's sex, age and other characteristics. This suggests sound recordings can help scientists count the number of lions in a landscape and thus make population density estimates, Growcott said.

For the study, the researchers deployed 50 custom-built microphones in Tanzania's Nyerere National Park and attached acoustic sensors to collars on five lions in Zimbabwe's Bubye Valley Conservancy area. In total, the team recorded 3,149 African lion (Panthera leo) vocalizations.

The team then used artificial intelligence (AI) to analyse the sounds, which revealed the intermediate roar.

Without AI, understanding full-throated roars and identifying lions based on their vocalizations has always been subjective, Growcott said. Lions also make other sounds — including grunts, snarls, chuffs, moans and mews — but only full-throated roars have been shown to hold identifiable signatures, so it is important to identify these roars correctly and extract as much information as possible from them.

The researchers' AI model enabled them to classify lion vocalization types with over 95% accuracy, largely removing the bias that is introduced when researchers try to characterize lion calls manually. This approach also made it easier to identify individual lions based on their full-throated roars, and highlighted the previously unknown intermediate roar — knowledge of which will help researchers to isolate full-throated roars in the future.

"This new method which proves that intermediary roars exist and are different to the full-throated roar is an important first step for ensuring consistency in selecting full-throated roars," Growcott said.

There are only about 23,000 African lions left in the wild, making the species vulnerable to extinction, according to the IUCN Red List. Traditional methods to estimate lion population sizes include camera traps and spoor surveys, but these require large resources and may be less accurate than acoustic surveys.

"I hope that using data-driven predicted full-throated roars will lead to more accurate acoustic population density estimates which can better inform the pressing needs of conservation," Growcott said.

Big cats quiz: Can you get the lion's share of these questions right?

Five wild female bonobos in the Democratic Republic of the Congo brutally attacked one of their male group mates, disfiguring his face almost beyond recognition, ripping off one of his ears, and biting his testicles in an unprecedented act of violence for the species, scientists report.

Researchers arrived a few minutes late to the scene, so they aren't entirely sure what sparked the ferocious act, which lasted around 30 minutes. However, they suspect the male bonobo may have tried to harm one of their infants, the authors reported Oct. 6 in the journal Current Biology.

"We didn't see the onset of the attack, but it's hard to explain in other ways, like what's the function of this remarkably extreme violence," study lead author Sonya Pashchevskaya, a doctoral researcher at the Max Planck Institute of Animal Behavior in Germany, told Live Science.

There has been only one other documented case of such an attack, in a different bonobo population around 186 miles (300 kilometers) away, and that appeared to be punishment for attempted infanticide, she explained.

This recent assault, which happened Feb. 18 in the LuiKotale bonobo community in Salonga National Park, is the most extreme case of violence in a wild bonobo population to date and challenges the stereotype of bonobos being the nonviolent "hippies" of the primate world.

Bonobos (Pan paniscus), along with chimpanzees (Pan troglodytes), are our closest living relatives. But unlike chimpanzees, bonobos have a reputation for "making love, not war," with individuals frequently using sex to relieve tensions.

However, male-male aggression is still common, and female bonobos are known to team up to fight males who threaten them or their young. This female "coalitionary" behavior seems to underpin the female dominance hierarchy in the species and could explain the "lack of lethal aggression or infanticide" in bonobo societies, the authors noted in the study.

There was nothing untoward on the morning of the attack. "It was a usual data collection day," Pashchevskaya noted. The team, which included local field assistants and research assistants, were following small subgroups of bonobos from the roughly 60-strong LuiKotale community through the forest.

Suddenly, bonobo screams erupted from roughly 0.3 miles (0.5 km) away. Pashchevskaya assumed the high-pitched screeches were excitement from catching small antelope prey.

"The bonobos who I was with at that time, they all just drop from the trees and start sprinting down there," she said. She followed in hot pursuit and arrived at the scene just a few minutes after it all started.

"First thing that immediately happens is, I smell blood," Pashchevskaya recalled. When the team spotted a group of five females stomping on, beating and biting a male lying head down on the ground, she realized this was not about an antelope hunt.

The male victim, a 19-year-old called Hugo, lost most of his hair in the assault, as well multiple toes, part of his ear, and the flesh on his knuckles. The assailants then licked his blood off their fingers.

No group member tried to intervene, despite the entire community being present. "Everybody is very silent. It's like a forest with bonobos has never been so quiet," Pashchevskaya said. "This is nothing I've ever seen before."

Two days before, Pashchevskaya noticed Hugo trying to grab one of the attacker's infants, which the team speculated may have sparked the attack as an act of retaliation.

"Of course, this is just one observation two days before, but if this kept happening, it could have potentially triggered an attack," she said. "Other females would join this potentially, because this is then someone they can also recruit [in the future]."

Hugo eventually managed to walk away, but has since been missing, leading the team to suspect he died from his injuries. "There's no way he survived," Pashchevskaya said.

Nahoko Tokuyama, a primatologist who researches bonobos at Chuo University in Japan but was not involved in the recent work documenting the attack, said that although she wasn't surprised by the group assault, she did not expect such grave injuries.

"I had previously believed that wild female bonobos, while sometimes becoming violent, would not injure an opponent to such a severe extent," Tokuyama told Live Science in an email.

However, she cautioned that Hugo may still be alive. "Bonobos have a fission-fusion society, and it is possible for a male to spend long periods alone," she said. "In our long-term studies, we have had cases where males who had not been seen for several months returned to the group, so the question of whether Hugo died needs to be considered more carefully."

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?

While often miscast as mysterious or hard to understand, cats are actually excellent communicators. In fact, in free-ranging cat colonies, physical fights are kept to a minimum through clever use of body posturing, scent exchange and vocalisations.

Cats have also adapted their communication for humans. For instance, adult cats don't usually meow at each other. But when around people, cats meow a lot, suggesting they have adapted this vocalisation for communicating with humans.

And it's not just the meow. Cats have a wide vocal repertoire for conveying different meanings, even for specific people. Bonded cats and humans often develop their own communication repertoires, similar to having a unique dialect.

Cats can understand human communication too. Studies show cats know their own names and the names of their companions, and can recognise human emotions, even changing their own behaviour in response.

Despite all this, humans still routinely misunderstand cats. Our new study, published in Frontiers in Ethology, shows just how little people understand the cues cats give. Try the quiz below to see how well you speak cat.

What we did

We asked 368 Australian participants to watch videos of human — cat play interactions. But not all the videos were "play" for the cat. Only half of the cats were playing, while the other half were actually showing signs they didn't want to play, or were feeling stressed by the interaction.

After each video, participants were asked if they thought the interaction was overall positive or negative for the cat, based only on the cat's behaviour. They were then asked how they would interact with the cat in the video they had just seen.

How well do you speak cat?

Watch the short videos below and decide: is the cat feeling positive or negative about the interaction? Remember to base your answers only on the cat's behavior.

What did our study find?

Results showed that participants struggled to recognize negative cues indicating discomfort or stress in cats.

For videos of cats who weren't playing and were showing subtle negative cues (such as sudden tension in the body or avoiding touch), participants only recognized the negative cues about as well as chance (48.7%).

Even when participants watched videos of cats showing overt negative cues like hissing, biting or trying to escape, they still incorrectly categorised these as positive 25% of the time.

Recognizing when a cat is stressed is only the first step. We also need to know how to respond to these cues.

Even when participants did successfully recognize negative cues, they often chose to engage with the cat in ways that would cause more stress and increase the risk of human injury, such as stroking, belly rubbing and playing with hands.

Stress is unhealthy

Stress can have serious consequences. Cats who experience regular or prolonged stress (including from unwanted interactions like those in the negative videos) are at higher risk of heath issues such as bladder inflamation.

They're also more likely to develop behaviours people find problematic, such as increased aggression or urinating outside of the litter tray. In turn, these behaviors increase risk of the cat being euthanised or rehomed.

Cat stress is bad for humans, too. If a person doesn't heed early warning signs, the cat may bite or scratch, depositing bacteria and microorganisms deep into the skin. Rapid infection follows 30% – 50% of cat bites. If not treated promptly, it can lead to serious complications including sepsis, chronic health issues and even death. Cat bites and scratches can also transmit zoonotic diseases such as cat scratch disease.

How to play safely with cats

Watch for early warning signs a cat isn't enjoying themselves and stop if you notice any. By the time cues are obvious, cats are already experiencing distress.

Early warnings include turning away, dodging or blocking attempts to touch, flinching, body tension, ears back or to the side, lip/nose licking and tail thrashing, slapping or tucking.

Touch

Avoid sensitive areas such as the belly, paws or the base of the tail. Cats prefer to be touched on the head and neck.

Avoid using hands to play. It teaches cats that hands are toys, and increases the risk of accidental injury. Instead, use toys that keep your face and hands away, such as a wand toy with a long handle.

Tail

Tail movements aren't always a negative sign — they just mean the cat is emotionally stimulated and that could be from stress or excitement. Cats also use their tails for balance. So it's best to consider the tail in combination with the whole body and the context.

Changes in tail movements can also give important clues to the cat's mood. Generally, the bigger the movement, the more intense the feeling. So, if the movements start to get bigger or faster during play, or if a tail goes from relaxed to swishing when you touch, that might be a sign to back off.

Ears

Cats' ears are like antennas that swivel and adjust to pinpoint sound, but they can also give us a clue to how they are feeling. If the ears move for a moment and then return to a relaxed position, that usually means they're listening to the world around them. If the ears remain flattened and back, that's a sign of distress.

Vocalisations

Trilling and chirruping both suggest a playful cat, while hissing, growling and yowling all indicate stress. Purring might seem positive but may indicate a cat is stressed and trying to self soothe.

Let them be

When early warnings don't work, cats may show overt signs such as hissing, growling, trembling, hiding and, ultimately, biting or scratching.

If you notice warning signs, give the cat plenty of space. When stressed, cats don't like being touched or having people too close. If the cat comes back and re-initiates contact, that's a good sign they're comfortable, but keep watch for warning signs returning.

If you pay attention to your cat's behavior and give them space when they need it, with a bit of practice you might just become fluent in cat.

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

Chimpanzees use a variant of the "scientific method" — discarding prior beliefs if convincing new evidence comes along to change their minds, new research suggests.

When tasked with finding a tasty treat hidden in one of two boxes, chimps (Pan troglodytes) evaluated several strands of evidence. And they switched their choices if new, contradictory evidence emerged, the study found.

The findings are evidence that chimps use metacognition, or thinking about thinking, to weigh evidence and plan accordingly.

"When they revise their beliefs, they actually explicitly represent the evidence they have, and they weigh different types of evidences," study co-author Jan Engelmann, a comparative psychologist at the University of California, Berkeley, told Live Science.

Humans routinely use metacognition to weigh different strands of evidence and create plans based on the information available. We also update our strategies when our plans don't go as we hoped.

Scientists have long known that primate species can assess evidence. Chimpanzees look for food by tracking crumb trails and will seek out more information if existing evidence isn't clear. But we didn't know if chimps could perform a key metacognitive task: changing beliefs in response to new evidence. Engelmann's team used several behavioral tests to answer this question, all of which involved food rewards placed in one of two boxes. In the first two tests, the chimps were trained to choose one of the boxes to receive the food inside and presented with two pieces of conflicting evidence as to which box contained the food. The chimps were presented with one piece of evidence, chose a box, and then given the other piece of evidence and allowed to choose again.

The evidence varied in strength. In one "strong" evidence condition, the team cut a window into the side of one of the boxes, which enabled the chimp to see the food inside. To give "weak" evidence, the researchers shook the other box to indicate something was inside it. The apes were far more likely to change their minds when the researchers presented strong evidence after their initial choice than when they presented weak evidence.

But these results didn't tell the researchers why the chimps changed their minds.

"You can revise your beliefs without really thinking about the evidence," Engelmann said.

The researchers arranged a third test in which they showed the chimps three boxes. One box had strong evidence that it contained food, the second had weak evidence, and the third had none. Before they could pick, the "strong evidence box" was removed. Left with a binary choice, the apes consistently picked the weak evidence over no evidence at all. This showed that the chimps considered both the strong and weak evidence in their decision-making, rather than just considering the strong evidence without reflecting on the other options available, Engelmann said.

In the final experiments, the researchers tested two further metacognitive abilities in the apes. This time, after the researchers presented the weak and strong evidence for the two boxes, they offered another piece of weak evidence. This was either the same weak evidence as before — the researchers rattling the box to show something was inside it — or a new piece of evidence: the sound of a researcher dropping a second piece of food into the box.

The apes were more likely to change their mind and choose that box when they heard two different pieces of evidence, rather than the same piece of evidence twice, showing that they considered how various pieces of evidence combined to strengthen an argument.

In the final test, the researchers again added extra evidence for the apes to consider after they had made their first choice. This time, the new evidence undermined the first piece of evidence; for example, by showing the chimps a pebble inside one of the boxes that could have made the rattling sound they had previously heard. The apes consistently responded to this contradictory evidence by changing their mind.

To Cathal O'Madagain, a cognitive scientist at the University of Mohammad VI Polytechnic in Morocco who was not involved with the study, this final experiment was key to proving the apes' metacognitive ability. "Study five is showing a kind of rationality that studies one and two are not showing," he told Live Science. Test five showed that the original and contradictory evidence were linked, and the apes' changed minds reflected that they were "keeping track" of the original information, he added.

O'Madagain said that the paper, in concert with other, earlier studies of chimpanzee rationality, shows that chimps passed what he called the "high bar" of rationality, making choices based on evidence and keeping that evidence in mind as their world changed. The new findings suggest that discoveries about other animals' minds aren't limited by their shortcomings, but by our own, O'Madagain said "The biggest constraint on our understanding of other animals' intelligence is our ability to come up with appropriate ways to check it."

Engelmann and his team now plan to extend their experiments to other non-human primates to see if they can pass this rationality test, too.

Lab monkeys initially thought to be carrying a range of diseases have escaped from a truck in Mississippi following a crash — prompting law enforcement officers to kill a number of the animals. However, it's still unclear just how dangerous they are.

The truck, which was carrying rhesus macaques (Macaca mulatta) from Tulane University, overturned in Jasper County on Tuesday (Oct. 28), with several monkeys breaking loose — although the exact numbers have yet to be reported.

At the time of writing, three monkeys are still on the loose, according to an update from the Jasper County Sheriff's Department. The authorities believed that the monkeys were aggressive to humans and carried herpes, COVID-19 and hepatitis C. But Tulane University has subsequently said that the monkeys weren't infectious.

"The primates in question belong to another entity & aren't infectious," Tulane University wrote in a post on X on Tuesday. "We're actively collaborating with local authorities & will send a team of animal care experts to assist as needed."

Following Tulane University's statement, the sheriff's department clarified that the driver of the truck had told law enforcement that the monkeys were dangerous.

"The driver of the truck told local law enforcement that the monkeys were dangerous and posed a threat to humans," Jasper County Sheriff's Department wrote in a post on Facebook. "We took the the appropriate actions after being given that information from the person transporting the monkeys. He [the driver] also stated that you had [to] wear PPE equipment to handle the monkeys."

Sheriff Randy Johnson has since said that the monkeys still needed to be "neutralized" because of their aggressive nature, the Associated Press reported on Wednesday (Oct. 29).

Are rhesus macaques dangerous?

Rhesus macaques are medium-sized monkeys, and they could pose a threat to humans if they decided to attack. However, it's unclear whether the escapees were likely to do that.

The sheriff's department wrote on Facebook that the escaped monkeys each weighed approximately 40 pounds (18 kilograms). This would be exceptionally large for a rhesus macaque and is likely an overestimate, unless the individuals were overweight. Male rhesus macaques, which are larger than females, typically weigh about 17 pounds (7.7 kg), according to the University of Wisconsin–Madison's Wisconsin National Primate Research Center, while the New England Primate Conservancy states that this species can weigh up to 22 pounds (10 kg).

Aggression is a natural part of macaque behavior, and while they don't normally direct it at humans, they regularly scrap among themselves. The New England Primate Conservancy states that fights between monkeys can be frenzied and violent, with rhesus macaques aiming for the eyes, face, limbs and genitals in order to maim or kill their opponents.

In other words, rhesus macaques can be dangerous if they want to be. Although they also have a range of peaceful behaviors, such as grooming.

Rhesus macaques have the widest geographic distribution of any non-human primate and can frequently be found living in close proximity to humans across their native range of Asia. They are often considered pests because of their penchant for stealing our food. Macaque species do occasionally bite or attack people, but this is a consequence of them becoming too habituated to humans in our expanding urban environments and losing their natural fear of people.

Macaques in labs, like the ones that escaped in Mississippi, have historically had a reputation for being aggressive, but experts have also argued that this aggression can be brought on by poor husbandry and handling practices. Lab monkeys are sometimes hand-reared by humans, which can lead to a range of abnormal behaviors not typically seen in the wild or in captive monkeys raised by other monkeys, such as self-biting and more aggression toward humans. Each individual monkey also has its own personality. And captive monkeys can have relatively calm and gentle demeanors.

There aren't any reports of the escaped monkeys attacking humans before they were killed. Tulane University has also said that the monkeys had "not been exposed to any infectious agent," the Guardian reported.

There are still a lot of unknowns surrounding the monkeys, including who owned them, who was transporting them, where they were heading, and for what purpose they were being used, according to the Associated Press.

Lab monkeys

Rhesus macaques are the most common monkeys used for testing in labs. Experimenting on these monkeys can be extremely valuable to scientific research and has led to a plethora of breakthroughs, including the development of various vaccines, including mRNA vaccines against COVID-19.

The use of monkeys in labs is also controversial. For example, in 2023, hundreds of scientists called for an end to "cruel" monkey experiments at Harvard Medical School and elsewhere. These included visual recognition studies in which juvenile monkeys had their eyes sewn shut for their first year.

Macaques on the run

This isn't the first time lab monkeys have escaped. For example, in 2020, a group of macaques reportedly escaped from a lab in India and took several COVID-19 blood test samples after attacking a lab assistant, Sky News reported. More recently, 43 monkeys escaped from a lab in South Carolina and went on the run, the Associated Press reported.

The descendants of escaped rhesus macaques are also living in the Silver Springs State Park in Florida. In the 1930s, a commercial river boat captain put six macaques on an island as a tourism ploy, not realizing that rhesus macaques can swim. The monkeys soon left the island and spread along the river.

Two weeks on from Jane Goodall's death, many have been reflecting on her life, including her scientific legacy and how she changed humanity's connection to the natural world.

As a pioneering primatologist, Goodall was the first to spy many behaviors and characteristics in the chimpanzees (Pan troglodytes) of Tanzania's Gombe National Park that had been assumed to be unique to humans, including tool use, warfare and personalities.

Goodall’s observations revolutionized our understanding of chimps; and her unconventional approach, stemming from a lack of formal scientific training, enabled her to make several contributions that changed the face of animal research. Yet this would prove to be a double-edged sword, leading her to use methods that primatologists no longer consider helpful today.

So what were Goodall's contributions to primatology? And did any fall short? Live Science spoke to chimpanzee experts to unpack her enduring impact on chimp research, including how some of her initial observations biased our understanding of how chimps think and behave, and the ways scientists have learned from the unintended consequences of her early decisions.

One of the most notable examples of Goodall’s unwitting defiance of strict scientific conventions can be found in her giving individual names to the Gombe chimpanzees and remaining open-minded to their capabilities.

"She didn't know that she wasn't supposed to give them names. She didn't know that you weren't supposed to talk about feelings and emotions and personal histories," Elizabeth Lonsdorf, a professor of anthropology at Emory University who studies the Gombe chimps, told Live Science. "Her real gift to us was firmly planting that as a basic understanding of chimpanzees so that we can design better science with that in mind."

Recognizing the need to consider the personal histories of chimps was pivotal, and by establishing the first long-term study of chimps, Goodall ignited an entire research field. The Gombe chimps are now followed daily by a dedicated team of expert Tanzanian trackers, and, since 1960, scientists have collected over 165,000 hours of data on their behavior.

Researchers can now track chimpanzees' development from birth to old age using these data, watching how each generation transfers skills and knowledge onto the next. "Chimps live 60 years so you can't actually ask those questions without five, six decades of research," Lonsdorf said.

The Gombe community now contains the fifth generation of chimpanzees descended from the original chimps Goodall studied, with family lineages grouped according to the first letter of their mothers' names.

'Friendship' as the 'F'-word in primatology

Naming chimps goes beyond tracking, and has opened the door to new research avenues. Laura Simone Lewis, a primatologist at the University of California, Santa Barbara, told Live Science that while captive chimps clearly respond to their own names, she is currently investigating whether they also recognize those given to their groupmates.

Finding evidence that chimps keep track of each other's names would suggest that the underlying capacity to understand social labels could have emerged before the evolution of human language, Lewis said. "That comes directly from Jane's work of naming chimpanzees."

This research also carries on Goodall's work of investigating social bonds in chimps. Lewis noted that many of Goodall’s early observations about the social and emotional lives of chimps were anecdotal, and so were discounted.

In fact, "friendship" was considered the "f" word in primatology for over 40 years after Goodall's first observations. Lewis is still careful when using the term, yet its growing acceptance among primatologists is based on years of empirical research, and points to the validity of Goodall's first insights. "We often call them close social relationships, but what they really are are friendships. And they are long-lasting, very closely bonded relationships between animals that can last for decades."

This sentiment is echoed elsewhere. Liran Samuni, a primatologist at the German Primate Center who studies cooperation and intergroup relationships in chimps, said that despite chimps' bad reputation for aggression, she "cannot think of a primate species [aside from humans] that is also as cooperative and as dedicated to each other as chimpanzees are."

The distinction is that chimps are very friendly to their ingroup and "systematically hostile to the outgroup," Sylvain Lemoine, a primatologist at the University of Cambridge, told Live Science.

Chimpanzees' "social landscape is made of their own community and of the neighboring communities," Lemoine said. And at any time, they run the risk of being ambushed by hostile neighbors, he added.

Goodall’s observations on chimp aggression were also foundational. She was the first to observe lethal aggression between chimpanzee groups, and documented what has become known as the Gombe Chimpanzee War, which was a four-year-long conflict caused by the splintering of the Kasakela community.

At first, Lemoine said, researchers dismissed this as an artificial behavior that resulted from Goodall feeding the chimps bananas — called "provisioning." By plying the chimps with food, Goodall could entice the whole group to one central spot to observe their interactions more easily. However, this high concentration of sought after resources dangerously heightened the competition between the chimps.

It is now known that intergroup violence is common across chimp populations, and "whether this community in Gombe split because of the provisioning is another question," Lemoine said.

This exemplifies an important point, however. While Goodall's open-mindedness meant she ignored unproven presumptions made by experts during her time, such as warfare being unique to humans, she also made decisions that ultimately had unexpected negative repercussions.

Not all chimps are Gombe chimps

The fact that Goodall’s early work was centred on one community at one site, Gombe National Park, also created another unintended consequence: The long-lasting assumption that the behavior and social structure of the Gombe chimps was the same across all chimp communities. "This is something that people who study chimpanzees are still grappling with," Samuni said.

We now know that chimps across Africa can vary considerably from one another. For example, the intensity of intergroup competition among chimps varies depending on the animals’ social structures, Samuni told Live Science, with a 2014 large-scale study published in the journal Nature finding that East African chimps were more lethal than those in West Africa. They also found that groups with more adult males witnessed a greater number of killings.

Also, Goodall observed that female chimps were antisocial, generally sticking to themselves while males gathered to interact. This is true on its face: Females in East African chimp communities, like those in Gombe, do tend to be more peripheral members of the group, Samuni explained.

But this is far from true everywhere. Females in West African chimp communities are "extremely central to the social network," Samuni said. Nonetheless, the first impression made by Goodall’s observations left a long-lasting presumption that all female chimps were antisocial, a bias that took years to overturn.

However, Lonsdorf said that she never viewed Goodall's work as putting blinders on researchers. Goodall's observations simply lay the groundwork for studying variation by developing a "baseline framework of how a chimpanzee behaves," she said.

Times have changed

A lot has changed since Goodall's initial observations. These days, the Gombe chimps are given Swahili names rather than English ones, and naming individuals in the local language is common across sites. In addition, chimpanzees are no longer provisioned at any site.

Also, researchers can now collect data beyond observations. "Nowadays, our science is largely interdisciplinary or multidisciplinary," Alejandra Pascual-Garrido, a primatologist at the University of Oxford who works with the Gombe chimps, told Live Science. There is now a genetics lab in Gombe, making it possible for researchers to study paternity and the health of the gene pool.

The days of closely interacting with chimpanzees as Goodall did are likewise long gone. Researchers now wear masks to avoid getting animals sick and keep their distance to stay safe, and primatologists work to ensure photographs of people very close to primates aren't shared as they can undermine conservation efforts and encourage the pet trade. Pascual-Garrido noted that the old images of Goodall hugging chimpanzees would be considered "completely unacceptable" by primatologists nowadays.

It's important to remember that Goodall was doing what seemed to work at the time, and had no other site to learn from. Samuni said "the fact that she did not come with those predefined ideas and concepts actually allowed her to see things that other people may have missed or may have thought, 'okay, it cannot exist.'" Pascual-Garrido agreed. "She saw the world differently and she made the world see the world differently," she said.

A rat-shaped indent on a Chicago sidewalk went viral early last year, with troves of people venturing to the hole bearing coins and other offerings. However, a new study suggests the so-called "Chicago Rat Hole" wasn't actually made by a rat — it was probably the imprint of a squirrel.

By comparing characteristics of the hole with information about the local rodent populations, researchers determined that a squirrel most likely made the impression. The study was published Wednesday (Oct. 15) in the journal Biology Letters.

"Just like everyone else, I looked at it like, 'Yep, that's a rat,'" study lead author Michael Granatosky, an evolutionary biomechanist at the University of Tennessee, Knoxville, told Live Science. "But just assuming something is not the best way to actually do science."

The hole, a well-preserved imprint of a rodent's death in wet concrete, was around for decades before it went viral. It became a tourist attraction in 2024 after the Chicago-based artist and comedian Winslow Dumaine posted about its existence on the social platform X.

"Squirrels are a lot more TV-ready than rats are," Dumaine told Live Science. "But I do think the fact it was dubbed a rat hole was a key part in why it became popular."

As the researchers came across pictures of the hole on social media, some felt it didn't look "super rat-like," senior study author Edwin Dickinson, an archaeologist at the University of Calgary, told Live Science. It also seemed unlikely a rat could have made such a cast on wet concrete without also leaving footprints leading up to it. These suspicions drove researchers to analyze the hole more deeply.

Using the citizen science app iNaturalist, which catalogues local fauna, the study authors identified possible animals that could have made the hole. They knew, from the indent, that it had to be an animal with four legs, five-clawed feet and a tail.

Then, it was all a matter of proportion. The study authors didn't have a chance to measure the hole itself, which city officials removed in April 2024, citing the disturbance crowds were bringing to the Roscoe Village neighborhood. However, they were able to get precise measurements thanks to the many pictures people had posted of the imprint alongside coins and other items.

The researchers compared their measurements to specimens at the American Museum of Natural History. A statistical analysis of this data showed a 98.7% likelihood the hole was made by either an eastern grey squirrel (Sciurus carolinensis) or a fox squirrel (Sciurus niger) .

In light of this finding, the scientists suggested rechristening the rat hole as the "Windy City Sidewalk Squirrel" to better represent its origins.

The authors hope the study will help people see the fun in science.

"The rat hole might be the medium, but the idea that we're hoping to perpetuate in this study is… there's nothing too inherently complicated or scary about following the scientific method," Dickinson said. "It is something that we can all use in our lives."

Naked mole rats may have specific roles, including "toilet cleaners" and "garbage collectors," new research suggests.

The findings, published Wednesday (Oct. 8) in the journal Science Advances, hint that naked-mole-rat colonies are even more complex than scientists previously thought.

"Our findings reveal the distinct roles of breeders and the remarkable behavioral diversity among nonbreeders, underscoring the complexity of naked mole-rat social organization," Teruhiro Okuyama, a behavioral neuroscientist at the University of Tokyo, told Live Science.

Naked mole-rats (Heterocephalus glaber) are small, almost-hairless rodents that live in underground colonies of between about 20 to several hundred individuals. They are one of just two mammal species known to be eusocial, meaning they show advanced social organization, similar to bees or wasps. For eusocial mammals, the queen reproduces, while most of the other members of the colony — which can stretch across several miles of tunnels — are sterile workers.

These workers perform an array of jobs, including soldiers, tunnel diggers, foragers and caretakers.

But it was unknown whether individuals switched jobs or tended to stick to specific roles. To investigate, Teruhiro Okuyama, a behavioral neuroscientist at the University of Tokyo, and his colleagues created an artificial burrow in their lab. It was made up of nine chambers, each 5.9 by 5.9 inches (15 by 15 centimeters), and arranged in a three-by-three grid. The adjacent boxes were connected by 6-inch-long (16 cm) pipes.

The mole-rats designated different chambers for specific uses, including a nesting place, a garbage area, a communal "toilet" and several compartments without specific functions.

For 30 days, Okuyama and his colleagues studied five colonies, each of which contained about 20 individuals, by implanting microchips in the mole rats and installing detectors throughout the colony box. This allowed the researchers to continuously monitor where the animals went and which individuals they spent time with.

They found that the breeding animals — the queen and a few males — stayed close to each other most of the time and followed each other around.

But the workers, they discovered, could be divided into six groups based on their movements. "They were doing different jobs if they weren't breeding," Okuyama told Live Science.

One group moved a lot and spent the most time in the garbage chamber, so Okuyama speculated that they might be transport specialists. Another cluster mostly occupied the toilet chamber, so the researchers proposed that these individuals might be cleaners.

A third group was less active and generally remained in the nest box. These were often younger animals, or individuals that were older and perhaps past their peak. "I think the job is gradually changing just depending on the age," Okuyama said."

Complex colonies

By revealing that there might be distinct roles for naked mole-rats apart from breeding or being a generic worker, the work underscores how much more complex their social organization might be than we thought, he added.

"It's a really interesting study," Chris Faulkes, an evolutionary ecologist at Queen Mary, University of London who wasn't involved in the work, told Live Science. "Anyone who has spent time looking at naked mole rats would agree that there are loads of individual things going on and certain animals will be spending lots of time in the toilet chamber, sweeping up or digging. It's a good attempt to quantify these complexities further."

However, Markus Zöttl, a behavioral ecologist at Linnaeus University in Sweden who wasn't involved in the work, said it's hard to draw too many conclusions from the observations.

"This paper shows that there is variation in behavior between helpers. There are some helpers that are more active, some that are resting more," he told Live Science. "But that's what you expect from any social animal. Some would be more proactive; others would be more socially aggressive; others are more timid. Some people might call this animal personality, and others would call it a caste system."

We should also be wary of jumping to conclusions about what happens in the wild based on a relatively small and simple lab burrow with short tunnels, Zöttl noted. "If you think about the ecology of these species, a burrow can spread over the area of a football field," he said.

Different behaviors could emerge in a complex, natural burrow system with long tunnels where animals need to dig to find enough roots to feed dozens or more colony members, rather than having food supplied, he said.

While traveling through these long tunnels, the animals often establish their place in the social hierarchy by shoving, interacting or avoiding each other as they pass, Faulkes said, which would then influence their behavior within the colony. However, he still thinks the lab work gives us new insights.

"There is this hidden behavioral complexity, and you've got groups or individuals that do very different things and interact in different ways within the colony," he said.