Using laser scanning technology to peer beneath the dense canopy of the Amazon rainforest, archaeologists have discovered hundreds of ancient earthworks that were made by a complex, enigmatic society over two millennia ago, a new study finds.

This ancient civilization, called the Aquiry, arose 2,500 years ago in Brazil. Based on the large number of earthworks, called geoglyphs, the Aquiry may have had 3 million people before the society collapsed, the researchers suggested in the study.

"The cultures and societies that composed the Aquiry shared a common worldview and constructed ceremonial centers in a variety of monumental geometric forms, characterized by deep ditches and high outer embankments, commonly known as Amazonian geoglyphs," Martti Pärssinen, an archaeologist at the University of Helsinki, told Live Science in an email.

In the new study, published Wednesday (July 29) in the journal Nature, Pärssinen and co-authors presented findings from their survey of nearly 1,740 square miles (4,500 square kilometers) of Amazonian rainforest, which revealed 396 new geoglyphs and allowed them to approximate the geographical extent of the Aquiry civilization.

Pärssinen has been investigating geometric earthworks in Brazil's Acre state for more than two decades. In a 2021 study, he officially introduced the name Aquiry for the multicultural ancient civilization, named after the Acre River, which flows from Peru and Bolivia through the present-day states of Acre and Amazonas in Brazil. Aquiry means "river of caimans" in the language spoken by the Indigenous Arawakan people.

Because of the dense canopy of trees in the rainforest, archaeological investigation in the area has been limited. Most of the evidence for the Aquiry civilization comes from lidar and airborne laser scanning of monumental geoglyphs that were constructed between 600 B.C. and A.D. 850, according to the study. People lived in multifamily longhouses around the earthworks, and they farmed crops like maize and squash.

"According to native oral traditions, the Aquiry centers were built to foster relations among communities" and with significant otherworldly beings, Pärssinen said. These centers also served as venues for gatherings and political decision-making, and they enabled chiefs to display their generosity, he added.

To date, archaeologists have identified around 1,700 known geoglyphs in the area. But the researchers think the total is significantly higher, with more than 20,000 Aquiry earthworks waiting to be found in places that haven't yet been surveyed. And based on an estimate of 300 people needed to build and maintain each geoglyph on average, the researchers estimated that the Aquiry civilization likely peaked at 1.25 million to 3 million people between A.D. 100 and 300.

Similar geoglyphs dating to between 200 B.C. and A.D. 500 have been found in Peru. Known as the Nazca Lines, these earthworks are shaped like animals, humans, plants and fantastical figures, in addition to having geometric motifs. The Nazca were an interconnected regional society of precolonial farmers who were able to survive in a forbidding geographic region, but they lived roughly 1,050 miles (1,700 kilometers) from the Aquiry.

"The Nazca geoglyphs represent a different phenomenon and were probably unrelated to the Aquiry civilization," Pärssinen said. "Nevertheless, in both cases, the straight roads and lines, as well as the geometric forms and motifs, are best appreciated from the air."

The presence of thousands of geoglyphs in the southwest Amazon region is leading archaeologists to rethink assumptions about precolonial civilizations and urban development — but it's also bringing up questions about the fate of the Aquiry.

"We do not know why the geoglyphs were suddenly abandoned between A.D. 850 and 950," Pärssinen said. "The available evidence points to a relatively rapid collapse" that may be related to the disappearance of other major precolonial powers, he said, "including the Classic Maya in Central America and the Tiwanaku and Wari civilizations in the Andes."

How much do you know about the first people to reach the Americas? Find out with our First Americans quiz!

The Amazon is the largest rainforest in the world, spanning more than 2 million square miles (5.2 million square kilometers) — an area 12 times the size of California. It influences global water cycles, stores years of global carbon emissions, supports 47 million people, and is home to the greatest concentration of biodiversity on Earth.

But the Amazon rainforest is also disappearing, with 17% of it already cut down or destroyed and largely replaced with agriculture. Other grave threats, such as oil drilling and illegal mining, continue to whittle it down. The next century may have outsize importance, as the forest could reach a "tipping point."

So what will the Amazon rainforest look like in 100 years?

The answer depends on a number of compounding threats, Bernardo Flores, a researcher with the EqualSea Lab at the University of Santiago de Compostela in Spain, told Live Science.

Encroaching farmland and organized crime are a couple of the problems chipping away at the Amazon. But those work in tandem with what he considers the three main threats: climate change, which can lead to extreme weather events, "like wetter wet seasons and drier dry seasons," deforestation and fire.

As the Amazon loses more of its forest, it triggers a feedback loop. "You have less rainfall; then you have less forest, [then] less rainfall, less forest," Flores explained. "That ultimately leads to "a global scale feedback involving the Amazon: More forest loss [leads to] more global warming. More global warming, more forest loss."

As forests get drier, it becomes easier for wildfires to burn more areas. Roads also degrade the forest, and "wherever you have roads, you have people doing illegal activities, illegal logging … then this leads to [more] forest fires," Flores said.

The "arc of deforestation" — a roughly 310,000-square-mile (800,000 square km) border along the Amazon considered the largest deforestation frontier in the world — offers a preview of what much of the Amazon could ultimately look like, according to Flores. The forests that remain there have higher tree mortality and more canopy gaps, and they are often "covered with lianas," or woody vines, that become an ecological problem, he said. Lianas compete with trees for light and nutrients in the soil, and significantly reduce not only a tree's chance of survival but also the overall diversity of trees in a forest. "When the whole forest is covered in lianas, you don't see the forest anymore," he added.

Invasive grasses introduced by cattle farmers will likely proliferate in the decades ahead, but "only a few parts" of the Amazon could become "a savanna, because a savanna is a native, biodiverse ecosystem," he said. Invasive grasses "exclude native species, reduce biodiversity" and would not allow native savanna grasses to replace the forest, Flores said. Instead, one possibility is a "degraded open-canopy ecosystem," where native, naturally fire-tolerant trees, combined with invasive grasses, vines and ferns, proliferate, Flores told Live Science.

Wildlife would quickly be affected as well. Aquatic species are especially vulnerable, Flores said. "When you start having these droughts that will simply last for one, two, three years," wetlands will dry out and become flammable, he explained. That could lead to "very quick extinctions in those areas."

The destruction of the Amazon rainforest would be disastrous for the Indigenous people living there, Christian Poirier, program director of Amazon Watch, an environmental and Indigenous rights advocacy group, told Live Science. "Imagine having your backyard bulldozed and your water source poisoned," he said. "You probably need to move from where you live, and that's exactly what's happening in the Amazon."

A devastated Amazon would also lead to "a more chaotic global climate system," Flores said. There could be less rainfall across parts of South America, and global warming will worsen. Earth could eventually reach a tipping point where ice sheets melt, ocean currents malfunction and the collapse of the Amazon accelerate warming all at once, pushing the planet to "cross the tipping point and transition to a much warmer climate," he said, leading to potentially irreversible consequences.

Unlike other major climate risks, such as the potential of the Greenland Ice Sheet melting and contributing to sea level rise, deforestation can in theory be reversed more easily by reforestation, said Arie Staal, an assistant professor of ecosystem resilience at Utrecht University in the Netherlands.

"That gives us a knob to turn that we don't have for other possible tipping points on Earth," he told Live Science. "It is clear that we really need to stop deforestation in the Amazon. And there's hope."

Editor's note: This article was updated at 6:23 p.m. EDT on June 22 to fix the conversion of roughly 310,000 square miles to 800,000 square kilometers.

Rainforest quiz: Can you sort the largest rainforests on Earth?

Rainforests are some of the most important and diverse ecosystems on Earth. Found across several continents, these vast forests are home to millions of plants and animal species, many of which can't be found anywhere else. Many rainforests, both tropical and temperate, also play a crucial role in regulating the planet's climate by absorbing carbon dioxide and producing oxygen.

Rainforests vary immensely in size. Some stretch across multiple countries and cover millions of square miles, while others are much smaller but still support incredible biodiversity. Understanding the relative size of these rainforests helps us appreciate their role on our planet and the challenges involved in preserving them.

In this quiz, you'll test your knowledge by sorting the top 10 biggest rainforests from largest to smallest. Click on and drag the blue rectangles to place them in the right order. Remember to log in to put your name on the leaderboard; hints are available if you click the yellow button.

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Around 1,000 years ago, a pre-Inca culture acquired wild parrots from hundreds of miles away in the Amazon rainforest and then kept them captive in what is now coastal Peru, all so people could access the birds' vibrant feathers, which were "prestigious symbols of status," a new study finds.

Researchers found some of these feathers in a 1,000-year-old tomb about 20 years ago. Now, a new analysis reveals the "complete journey of these feathers," including where the birds originated, what they ate, and which routes the live birds were likely carried on before being traded to the Yschma, a pre-Inca society that flourished from about A.D. 1000 to 1470.

While it's long been known that the Inca and other pre-Hispanic cultures traded and valued parrot feathers, the new study is one of the first to reveal that the "Ychsma culture, long before the Inca Empire, participated in a sophisticated trade network that spanned the Andes," the authors wrote in the study.

Researchers first discovered the burial in 2005 after a survey with ground-penetrating radar and a later excavation revealed two large, stone-lined tombs near the Temple of Pachacamac, 20 miles (32 kilometers) south of Lima. In one of the two Yschma tombs, the archaeologists found parrot feather ornaments with vivid colors that had been preserved for centuries.

Now, an international team of researchers has analyzed the feathers' DNA and chemical composition, and concluded that the feathers came from live Amazonian parrots that had been transported, and likely traded, across the mountains, before being kept in captivity on the Peruvian coast. Their new study was published Tuesday (March 10) in the journal Nature Communications.

"Our study proves that centuries before the Inca, societies like the Ychsma, the Chimú, and others were already managing sophisticated, organised, long-distance trade networks," study co-author Izumi Shimada, co-director of the Pachacamac Archaeological Project that originally found the tombs and a professor of anthropology at Southern Illinois University, told Live Science in an email. "They possessed profound ecological knowledge and negotiated trade agreements that connected the Amazon with the coastal deserts, revealing that these states [were] more interconnected."

The discovery shows how much effort these societies invested in what they deemed prestigious objects. At Pachacamac, these feathers were found adorning false heads — cloths filled with reeds and other plants — attached to 34 funerary bundles of deceased individuals who were also decorated with small cinnabar masks, suggesting that the feathers were used in ceremonial activities such as burial rites.

However, it appears that the captive birds weren't living at the temple.

"Our research actually suggests that the large-scale rearing of these captive birds may not have happened at Pachacamac itself (no parrot skeletons, eggshells, or signs of breeding houses were found), but further north maybe in the Chimú Empire, who then traded the harvested feathers south to the Ychsma," study first author George Olah, a research fellow at The Australian National University, told Live Science in an email. The proposed Chimú breeding site is based on the new paper's computer models, he added.

A sacred site

The Pachacamac temple and its oracle served as the heart of the Yschma society, which controlled the valleys around Lima before the Inca conquest around 1470. "Because of the widespread and longstanding reputation of Pachacamac, elites of diverse cultures in ancient Peru sought the privilege of being buried close to the temple," Shimada said. "It is believed that the site contained tens of thousands of burials of elites of different cultures and regions."

After the Spanish conquest in 1533, looters ransacked graves at Pachacamac for centuries, stealing and destroying countless Yschma artifacts. By the time the Pachacamac Archaeological Project began its work in the early 2000s, many researchers believed no intact elite tombs were left by the temple — so the discovery of the two tombs was an "exceptional event," the researchers wrote in the study.

Feather quest

In their investigation, the team looked at the mitochondrial DNA of 25 feathers found in the tombs and determined that the ornaments attached to the funeral bundles came from at least four tropical parrot species: scarlet macaws (Ara macao), red-and-green macaws (Ara chloropterus), blue-and-yellow macaws (Ara ararauna) and mealy Amazons (Amazona farinosa). All of these birds are native to lowland tropical forests east of the Andes, not to the Peruvian coast.

These birds lived hundreds of miles from the Ychsma, which suggests the society traded with others to acquire the birds.

"The fact that they ended up more than 500 kilometres [310 miles] away, on the other side of South America's highest mountain range, proves human intervention," Olah said in a statement. "They do not naturally fly over the Andes."

An analysis of the feathers' isotopes (variations of elements with varying numbers of neutrons in their nuclei) shed light on the birds' diets.

Unlike modern wild parrots' diets, which are rich in fruits and seeds, the ancient feathers from Pachacamac showed diets rich in plants like maize and possibly food linked to coastal agriculture enriched by seabird feces.

"Because they showed a coastal diet, it proves the birds were brought to somewhere along the coast alive and kept in captivity long enough to moult and grow new feathers with the isotopic signature we detected," Olah told Live Science in an email.

The macaw feathers also showed a higher genetic diversity in their DNA, unlike the low diversity expected from a small captive breeding colony. This suggested that local breeding was happening near Pachacamac and birds were being repeatedly sourced from Amazonian populations and moved through trade routes in the mountains.

"While it is tempting to think of them as pets, the archaeological evidence suggests they were maintained primarily for their feathers, which were valuable prestige items used in elite tunics, headdresses, and funerary bundles," Olah said.

Finding the routes across the Andes

To determine how these birds moved across the Andes, the team turned to computational models. They plugged in ancient topography, river systems and ocean conditions, and then ran a "least cost" path analysis to determine which routes would have demanded the least energy from human caravans.

The more efficient routes pointed to two likely corridors: one through northern networks tied to coastal regions where the Chimú Empire was located and another through central Andean passages connecting the coast to eastern lowlands.

"The recommended best paths actually made good sense and also aligned well with historical and archaeological evidence," Olah said.

Bird quiz: How much do you know about our feathered friends?

The biggest trees in the Peruvian Amazon store disproportionately more carbon than smaller trees do, a new study finds. But these larger trees are also the ones most likely to be harvested, which means more carbon is being released into the atmosphere, thereby reducing these forests' ability to act as carbon sinks, the researchers say.

Almost 60% of Peru’s land is covered by forests, the vast majority in the Amazon region where it accounts for around 11% of the total Amazon rainforest. Peru's current forestry law allows trees to be selectively harvested when they reach a minimum diameter, which ranges from 16 to 24 inches (41 to 61 centimeters) depending on the species. The terrain in the Peruvian Amazon makes accessing and removing trees difficult, so forestry companies prefer larger trees because they yield the most wood, which reduces transportation costs, labor and time. These trees also tend to be older and more mature, with denser, harder and more stable wood.

But these large trees also store the most carbon, and removing them returns much of that carbon to the atmosphere, study co-author Geomar Vallejos-Torres, an agricultural scientist at the National University of San Martín in Peru, told Live Science in a translated email.

To determine how much carbon is stored in these large trees, Vallejos-Torres and his colleagues measured hundreds of trees across five forests in the country, recording variables such as diameter, height, crown area and wood density to estimate aboveground and belowground biomass and stored carbon.

They found that carbon storage, both aboveground and belowground, increased disproportionately with increasing trunk diameter, with 16 inches being an important threshold. The forests they studied sequestered up to 331 metric tons per hectare (148 U.S. tons per acre) aboveground and 47 metric tons per hectare (21 U.S. tons per acre) belowground. The majority of that carbon — between 88% and 93%, depending on the species — was concentrated in trees larger than 16 inches in diameter. Breadnut trees (Brosimum alicastrum), for example, stored 11.4% of their total aboveground carbon in trees smaller than this cutoff point, compared with 88.7% in larger trees.

The work was published Jan. 25 in the journal Frontiers in Forests and Global Change.

The results show that Peru's forestry policy targets the trees that store the most carbon and suggest that the country should shift its forest policy to protect them, Vallejos-Torres said.

"Given the urgency of keeping carbon reserves out of the atmosphere, it is necessary to conserve trees larger than 41 cm," he said. "This also allows for the conservation of forest biodiversity and microfauna, buffering the microclimate in the face of future climate changes."

Size isn't everything

But some researchers say tree size is not always the most important consideration for carbon sequestration. Ulf Büntgen, a professor of environmental systems analysis at the University of Cambridge who was not involved in the research, said the length of time the carbon is stored is more relevant.

"The paper talks not much about tree ages and thus ignores carbon residence time, which is overall low in the tropics," he told Live Science.

Vallejos-Torres countered this argument, however, saying that the largest trees continue to accumulate carbon for centuries, while smaller ones grow too slowly to make up the difference.

"The regeneration of smaller trees is slow, uncertain and often limited by degradation, disturbance and microclimatic changes, so the lost carbon is not recovered on timescales relevant for climate mitigation," he said.

The relationship between tree diameter and carbon stocks highlighted in the study is both empirically valid and relatively intuitive, said Martin Perez Lara, director of forest climate solutions impact and monitoring for the World Wildlife Fund. But he added that focusing only on tree size is not the best way to design a climate-friendly forestry system.

"A large share of research shows that well-designed management systems, including selective harvesting forests — including some trees around 40 cm — can contribute positively to climate mitigation and reducing degradation risks, and support long-term carbon dynamics," he told Live Science.

Despite the urgent need to preserve carbon sinks in the Amazon, Vallejos-Torres does not have much faith that the necessary changes to Peru's forestry policy will be forthcoming. "A legal reform that protects the largest trees would directly affect the economic interests of the timber sector, which depends on the extraction of these individuals of high commercial value and has an important weight in forestry policy decisions in the country," he said.

In 2024, scientists announced the discovery of a newfound anaconda species in the Ecuadorian Amazon. Now, in a new nature series, filmmakers have released nail-biting, never-before-seen footage of the moment they encountered the snake in the wild.

The footage transports viewers to the Baihuaeri Waorani Territory in the Amazon rainforest, where researchers were sampling anacondas in 2022 for a snake genetics study. In the video, venom expert Bryan Fry and actor Will Smith travel by boat with Indigenous Waorani guides along the banks of a murky river. In a small clearing, the group spots a gigantic anaconda, which the guides manage to immobilize so that Fry and Smith can take a piece of its scales.

The anaconda in the footage — which features in an episode of National Geographic's upcoming "Pole to Pole with Will Smith" docuseries — is a female measuring 16 to 17 feet (4.9 to 5.2 meters) long, Fry estimates in the show. There is a danger she might bite, says one of the Waorani guides who helps pin down the snake, even if green anacondas aren't venomous. Anacondas are constrictors, meaning they kill prey by wrapping their bodies tightly around it, suffocating the animal before swallowing it whole.

The scale sample and others taken in 2022 revealed that green anacondas, which were previously thought to all belong to one species, actually form two separate species: Eunectes murinus, the already-identified southern green anaconda, and Eunectes akayima, the newfound northern green anaconda.

"Finding a new species is so often not a case of actively searching but rather having rigorous scientific process in place so that serendipity can strike," Fry, who is a professor of toxicology at The University of Queensland in Australia, told Live Science in an email. "The research into the genetics of the iconic green anaconda is textbook in this regard."

Genetic analyses indicate that E. murinus and E. akayima diverged 10 million years ago. Since then, northern and southern green anacondas have accumulated thousands of genetic differences adding up to a whopping 5.5% of their total DNA. By comparison, the level of mismatch between human and ape DNA is about 2%.

As its name suggests, the northern green anaconda inhabits the Amazon's northern basin, which includes parts of Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname and French Guiana. The southern green anaconda, on the other hand, is found in the Amazon's southern basin, which stretches across Brazil from Peru and Bolivia to French Guiana. Both species live in wetlands and rivers, spending most of their time submerged in water. Their olive-green coloring blends into their surroundings, which helps green anacondas ambush large prey such as capybaras (Hydrochoerus hydrochaeris), caimans and deer.

Green anacondas are the world's heaviest snakes, with some specimens weighing more than 550 pounds (250 kilograms) and exceeding 12 inches (30 centimeters) in girth. Female northern green anacondas grow the largest and heaviest, while their male counterparts have more slender bodies. This means female and male northern green anacondas hunt different prey and occupy different positions in the food chain, Fry said.

"Females and males live in the same environment, but they feed differently," he said.

The northern green anaconda is the fifth described anaconda species in the world — and there may be more hiding out there, Fry told Live Science. "Despite anacondas having a state of fame exceeding that of any other reptile, they are really poorly known," he said.

Knowledge of the northern green anaconda's existence is important in and of itself, but the difference in male and female diets could also give clues about the health of the ecosystem — and the people who live in it, Fry said. Female northern green anacondas feed lower in the food chain than males do, preying on animals such as deer. The males eat more predatory fish and caimans, meaning they accumulate more toxins leftover in the environment from events like oil spills than females do, he said.

Male northern green anacondas' diet resembles that of humans living in the Amazon. Therefore, the concentration of toxins in these anacondas provides an estimate of the pollution that people are exposed to — and that pollution is high, Fry said.

"The concentrations of the heavy metals cadmium and lead, potent endocrine disruptors that are the signature of oil spills, were over 1000 percent higher in males than females," he said. "That is not a subtle difference. That is a warning flare."

In light of these findings, Fry is developing a wild food guide for the Waorani. "Recommendations will include pregnant women and young children avoiding top-level predators likely to carry higher contaminant loads, such as arapaima and arowana [two types of predatory freshwater fish]," he said.

"Pole to Pole with Will Smith" premieres Jan. 13 on National Geographic, and Jan. 14 on Disney+ and Hulu.

How to watch "Pole to Pole with Will Smith" in the U.S.

"Pole to Pole with Will Smith" premieres in the U.S. on National Geographic and will be available to stream on Disney+.

The first two episodes will air from 9 p.m. ET / 6 p.m. PT on Tuesday Jan. 13 on TV. Then, on Jan. 14, all seven episodes will be available to stream in one go on Disney+.

How to watch "Pole to Pole with Will Smith" in the U.K.

"Pole to Pole with Will Smith" will also air on the National Geographic TV channel and the Disney+ streaming platform in the U.K.

The premiere is a day later than the U.S. release, landing on Jan. 14 at 8 p.m. GMT. All seven episodes will be available to stream on Disney+ for U.K. subscribers from Jan. 14.

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The Amazon rainforest is inching toward a "hypertropical" climate regime that has not existed on Earth for at least 10 million years, new research suggests.

Scientists predict this regime will cause more frequent and extreme droughts, which could lead to mass tree dieoffs. By 2100, hot droughts could bake the Amazon for 150 days of the year, extending even into the wet season, according to a study published Wednesday (Dec. 10) in the journal Nature.

"When these hot droughts occur, that's the climate that we associate with a hypertropical forest, because it's beyond the boundary of what we consider to be tropical forest now," study lead author Jeff Chambers, a professor of geography at the University of California, Berkeley, said in a statement.

Scientists think a hypertropical climate last existed between 40 million and 10 million years ago, during the Eocene and Miocene periods. The average global temperature during the middle Eocene was 82 degrees Fahrenheit (28 degrees Celsius) — 25 F (14 C) warmer than the average today — and previous research suggests forests near the equator had fewer mangroves and evergreen trees.

Currently, the Amazon rainforest experiences hot drought conditions a few days or weeks of the year. But due to climate change, the region's dry season — which typically lasts from July to September — is getting longer, and the annual proportion of hotter-than-normal days is increasing.

Chambers and his colleagues analyzed 30 years of temperature, humidity, soil moisture and sunlight intensity data from a patch of forest north of Manaus, a city in the heart of the Brazilian Amazon. The researchers also examined information from sensors that measured water and sap flow inside tree trunks at this site, which helped them understand how the trees coped with drought conditions.

During droughts, trees struggled to access water and stopped absorbing carbon dioxide (CO₂), the researchers found. That's because evaporation rates surged during droughts, reducing soil moisture. Trees responded by closing the pores on their leaves that control water and gas exchange with the atmosphere, so they preserved water. But this simultaneously blocked CO₂ absorption, which in plants is necessary for tissue growth and repair.

As a result, when drought conditions were extreme, a proportion of the trees died from CO₂ starvation. And when soil moisture dropped below a threshold of 33% — meaning only one-third of the soil's pores were filled with water — trees also developed bubbles in their sap that were akin to clots in human blood vessels, preventing normal circulation inside the plants' fluid-filled xylem.

"If there are enough embolisms, the tree just dies," Chambers said. The soil moisture threshold leading to this collapse was remarkably consistent across two El Niño years in 2015 and 2023, and it matched thresholds measured at another study site in the Amazon. "That was really surprising to everyone," he said.

Annual tree mortality in the Amazon rainforest is currently just above 1%, but it could rise to 1.55% by 2100, the researchers found. This may seem insignificant, but it makes a huge difference on the scale of the entire rainforest, Chambers said.

Fast-growing trees were more vulnerable to hot droughts than their slow-growing counterparts, because they needed abundant water and CO₂ to sustain this growth. This suggests slow-growing trees, such as the yellow ipê (Handroanthus chrysanthus) and the Shihuahuaco (Dipteryx micrantha), will eventually dominate the Amazon as temperatures rise — if these trees can cope with increasing water stress and the rate of temperature change, that is.

The results indicate that rainforests in other parts of the world, such as western Africa and Southeast Asia, may also be transitioning to a hypertropical climate regime. This shift has dramatic implications for Earth's carbon cycle, because rainforests absorb huge amounts of CO₂ that would otherwise end up in the atmosphere.

The predictions of what could happen to the Amazon by 2100 assume negligible reductions in CO₂ emissions, so "it's up to us to what extent we're actually going to create this hypertropical climate," Chambers said. "If we're just going to emit greenhouse gases as much as we want, without any control, then we're going to create this hypertropical climate sooner."

Trees of all sizes across the Amazon rainforest are getting fatter due to climate change, a new study shows.

Rising carbon dioxide (CO₂) concentrations in the atmosphere have created a more resource-rich environment for plants in the Amazon, leading to an average 3.3% increase in the circumference of trees at their base every decade since the 1970s, researchers have found.

"We knew that the total amount of carbon stored in the trees of intact Amazonian forests has increased," study co-author Tim Baker, a professor of tropical ecology and conservation at the University of Leeds in the U.K., said in a statement. "What this new study shows is that all sizes of trees have grown larger over the same period — the whole forest has changed."

This fattening is "good news," because it suggests Amazonian trees are more resilient to global warming than previously thought, study co-author Beatriz Marimon, a professor and tropical plant ecologist at Mato Grosso State University in Brazil, said in the statement.

Previous studies indicate that rising temperatures and CO₂ levels are pushing the Amazon rainforest ever-closer to a tipping point that could transform the ecosystem into a savanna in the next 100 years — but in the meantime, trees are making the most of the climate by locking away massive amounts of carbon and bulking up, the new research finds.

For the study, the researchers collected data from 188 plots across the Amazon rainforest, measuring what is known as the trees' basal area, or how much space their trunks occupy on the forest floor. Monitoring began in 1971 and ended in 2015, but different plots were observed for varying lengths of time during this period, with the longest continuous plot monitoring time being 30 years.

The team, made up of almost 100 tropical plant scientists, designed the study with several possible outcomes in mind. One of these outcomes, known as the "winners-take-all" response, described a scenario where only larger trees benefit from rising CO₂ levels. Large trees have more access to light and nutrients than smaller trees do, meaning they are more resilient to changing conditions, according to the study.

Another outcome, dubbed the "carbon-limited benefit" response, described a case where smaller trees benefit more from rising CO₂ because they are so resource-limited to begin with that any increase would have a stronger effect overall than in larger trees.

A combination of these outcomes, dubbed the "benefits shared" response, was also possible, the scientists wrote in the study.

The results, published Thursday (Sept. 25) in the journal Nature Plants, suggest the "benefits shared" response prevails — for now. "The trees in intact forests have grown bigger," Marimon said, adding that even the largest trees, which are typically more vulnerable to climate-related events such as drought and lightning, are thriving in places without deforestation.

However, the researchers noted that over time, increases in basal area could become more pronounced in large trees, which would then dominate the ecosystem at the expense of small trees.

"Large trees are hugely beneficial for absorbing CO₂ from the atmosphere and this study confirms that," study joint-lead author Adriane Esquivel Muelbert, an associate professor of tropical plant ecology at the University of Cambridge, said in the statement. "Despite concerns that climate change may negatively impact trees in the Amazon and undermine the carbon sink effect, the effect of CO₂ in stimulating growth is still there. This shows the remarkable resilience of these forests, at least for now," she said.

None of the studied plots showed declines in basal area, indicating that negative climate effects have so far been outweighed by rising CO₂ availability. But this could change soon, the researchers warned in the study, with a slowing of tree growth and a bump in mortality expected in the coming decades.

Slowing growth and higher mortality may arise from a combination of factors — including heat stress, water stress, wildfires and storms — which are already increasing in frequency and severity. Other than diminishing our carbon emissions, the best way to buffer the Amazon rainforest against these factors is to leave it intact, the researchers said.

"These results underscore just how important tropical rainforests are in our ongoing efforts to mitigate against man-made climate change," Esquivel Muelbert said.

Even a small slowdown to one of Earth's major ocean currents could nearly halve the rainfall over parts of the planet's rainforests, fueling droughts that could accelerate climate change, a new study warns.

The Atlantic Meridional Overturning Circulation (AMOC), which includes the Gulf Stream, plays a key stabilizing role in climates around the planet. Yet a number of studies indicate that the current is slowing, with some even suggesting its heading toward a disastrous collapse.

Now, a new study has analyzed 17,000-year-old climate records to connect the current's weakening with its effects on the planet's tropics. Published Wednesday (July 30) in the journal Nature, the research suggests that the possible impact presents "a stunning risk" that could send swathes of usually humid regions, in the Amazon rainforest and elsewhere, into drought.

"This is bad news, because we have these very important ecosystems in the Amazon," study lead author Pedro DiNezio, an atmospheric and ocean scientist at the University of Colorado Boulder, said in a statement. "The Amazon rainforest contains almost two years of global carbon emissions, making it a major carbon sink on Earth. Drought in this region could release vast amounts of carbon back into the atmosphere, forming a vicious loop that could make climate change worse."

The AMOC acts as a planetary conveyor belt, bringing nutrients, oxygen and heat north from tropical waters while moving colder water south — a balancing act that keeps both sides of the Atlantic 9 degrees Fahrenheit (5 degrees Celsius) warmer than it would otherwise be.

But research into Earth's climate history shows that the current has switched off in the past, and some studies have hinted that glacial meltwater released by climate change is causing the AMOC to slow. The worst-case scenarios predicted by some models suggest that the current may outright collapse sometime this century, leading to devastating and irreversible impacts felt across the globe.

Related: Atlantic ocean currents are weakening — and it could make the climate in some regions unrecognizable

These predictions remain controversial, yet the risks are large enough for scientists to have called for urgent investigation. The effects of a diminished AMOC would include plummeting temperatures in Europe and storms proliferating around the equator — but scientists have also pointed to other, less foreseeable, impacts in Earth's tropical regions.

To investigate these possible outcomes, the researchers behind the new study pooled data of ancient rainfall patterns preserved in cave formations and lake and ocean sediments. They then plugged them into climate models to simulate the shifts in the past and how they may change in the future.

These models predict that a weakening AMOC would cool the northern Atlantic, causing temperatures to drop in the tropical Atlantic and Caribbean. This change, accompanied by rising global temperatures due to climate change, would lead to a drop in precipitation over regions in the rainforest belt, with rainfall dropping by up to 40% over parts of the Amazon rainforest.

Yet despite this alarming prediction, the researchers stress that the situation isn't hopeless: Though the tropics may remain sensitive to small shifts in the AMOC's strength, they say it is unlikely to collapse completely.

The fate of the current, and how severely it slows, depends on tackling climate change now.

"We still have time, but we need to rapidly decarbonize the economy and make green technologies widely available to everyone in the world," DiNezio said. "The best way to get out of a hole is to stop digging."

Seven giant funeral urns dating to pre-Columbian times have been found deep in the Brazilian Amazon rainforest. A fisher who works in this little-known waterlogged area of the middle Solimões region, along the upper course of the Amazon River, made the discovery after a 50-foot-tall (15 meters) Paricarana tree fell over, revealing the urns buried beneath it.

The age of the urns is currently unknown; being Pre-Columbian, they're either centuries or millennia old. But their burial place — a human-made island — is extraordinary, although it's unknown if the culture that created the islands also crafted the urns, according to archaeologists at the Mamirauá Institute for Sustainable Development (IDSM) in Brazil.

Two of the larger ceramic urns — which measure up to 35 inches (89 centimeters) in diameter — contained human bones, while the others held a mixture of seeds and the remains of fish, frogs and turtles, said Geórgea Layla Holanda, an archaeologist at the IDSM who co-led the excavation. These seed and animal remains were likely part of the funeral ritual.

The finds are "unprecedented," she said in a translated statement from the Brazilian Ministry of Science, Technology and Innovation. The large urns do not have ceramic lids, "possibly because they were sealed with organic materials that decomposed," Holanda told Live Science.

However, somewhat similar ceramic finds have been made elsewhere in the middle Solimões area. In these cases, urns would have lids "representing the head, with structures on the sides imitating limbs," she said.

"The greenish clay pottery is rare but has been seen at other sites in the region," Holanda said. "We also found fragments with applied layers of clay on the exterior and painted red bands, though it is not yet possible to link these to any known ceramic styles."

Related: Why are there no bridges over the Amazon River?

Archaeologists already know that funerals involving urns generally included multiple stages, she added.

"After death, the body was left in a basket in the river so that fish would consume the soft tissues, or it was buried in the ground," Holanda said. "Afterwards, the disarticulated [jumbled] bones were cremated and placed inside funerary urns, which symbolized a new body, a new skin. Finally, many Amazonian cultures buried these pots beneath their homes."

Archaeology in the Amazon rainforest

The month-long fieldwork was planned in coordination with residents of the nearby community of São Lázaro do Arumandubinha, who first alerted researchers to the finding.

"This was a community-driven demand, which understood the historical importance of these objects," Márcio Amaral, an archaeologist at IDSM who co-led the excavation, told Live Science. The São Lázaro do Arumandubinha community advised the excavators when to avoid seasonal river flooding, since the archaeological site, called Lago do Cochila (or Cochila Lake), lies in a flooded zone with no access to firm ground.

To reach this remote area of the Brazilian Amazon, the research team traveled more than 24 hours by boat along the winding Amazon River from the institute's base in Tefé to the community, canoed 11 miles (18 kilometers) through flooded areas, and then walked for one hour through the forest along a trail the guides hacked out with machetes.

Because of the difficult conditions where the urns lay, excavations were carried out on a platform raised 10 feet (3 m) above the ground, built with wood and vines by community members.

The funeral urns were buried about 15 inches (40 cm) deep on an artificial island built by ancestral Indigenous people. These people used earth to make this island as well as others in the region, primarily to protect the community from river floods, Amaral said.

Now that the excavation is done, the researchers plan to date the urns. They also have additional local reports of urns at other archaeological sites in the region, including on nearby artificial islands.

Gold mining is literally sucking the Amazon rainforest dry, creating an environment where trees cannot grow, according to a new study.

Researchers found that suction mining not only degrades the soil, it also drains moisture and traps heat, creating extreme conditions where even seedlings cannot survive.

"It's like trying to grow a tree in an oven," study co-author Josh West, a professor of Earth sciences and environmental studies at the USC Dornsife College of Letters, Arts and Sciences, said in a statement.

Throughout the Amazon, gold mining accounts for nearly 10% of deforestation, and it's increasing significantly. The amount of land in the Amazon used for mining gold has doubled since 2018 following a sharp increase in the price of the precious metal, according to the Amazon Mining Watch. In 2023, an estimated 5,000 square miles (13,000 square kilometers) was being mined for gold.

The impact on the landscape is devastating, with ground temperatures reaching 145 degrees Fahrenheit (60 degrees Celsius) and several meters of dry sand, natural regeneration of the land is nearly impossible, except in areas near water sources.

In a study published Monday (June 2) in the journal Communications Earth & Environment, researchers were looking to find out why trees fail to regrow on land that has been mined for gold.

Related: Tropical rainforests could get too hot for photosynthesis and die if climate crisis continues, scientists warn

The scientists studied two abandoned mining sites in the Madre de Dios region of southeastern Peru.

This mining practice used at the sites, run primarily by small-scale ventures, uses a dredge that requires large volumes of water to suction sediment and sand from river and stream beds in search of gold particles.

The effect of "water cannons," as lead author Abra Atwood, a researcher at the Woodwell Climate Research Center, describes them, is that they wash away the clay- and nutrient-rich topsoil. The landscape is transformed into dry ponds, some as large as soccer fields, surrounded by mounds of sand up to 22 feet ( 7 meters) high.

The team used remote sensing methods; electrical resistivity analysis, a technique that measures how easily moisture moves through soil; soil property measurements; and thermal imaging cameras to assess the impact of mining on the land.

They discovered that mining waste acts like a sieve, allowing water to seep through much faster than in primary forest soils (nearly 50 feet (15 m) per day compared to just 0.2 feet (0.074 m) per day in the forest). This leaves the soil with less moisture and more heat, exacerbated by the lack of shade due to deforestation, making it virtually impossible for new roots to take hold. Replanted seedlings "simply die," Atwood told Live Science.

However, areas near the edges of the dry ponds and in low-lying zones have higher soil moisture, lower temperatures, and therefore better natural regeneration.

To gauge the magnitude of this problem, the team found that between 1980 and 2017, small-scale mining destroyed more than 367 square miles (950 square km)) of rainforest in this territory — an area more than seven times the size of San Francisco — and operations continue to grow, putting biodiversity and Indigenous territories at risk. "The current landscape in the suction mining areas where we worked provides very little in terms of ecosystem services beyond gold mining. Habitat loss will also deeply impact long-term biodiversity," Atwood said.

In response, the researchers propose specific recommendations for redesigning the landscape and improving water retention in the affected areas. The first step would be to fill the mining ponds to restore flat terrain. This would bring tree roots closer to groundwater, increase moisture retention, and stimulate plant regeneration. Then, the topsoil should be restored.

However, Atwood cautioned that these actions face significant financial, logistical, and even political challenges. Illegal gold mining impacts many Amazonian regions, including Peru, Brazil, Suriname and Guyana.

"Our message is to focus efforts on natural water sources to give reforestation initiatives the greatest chance of survival," she noted. "To address a large-scale problem, you need a large-scale solution, even if the financial costs are high."

"There's only one Amazon rainforest," West said in the statement. "It's a living system unlike anything else on Earth. If we lose it, we lose something irreplaceable."

Cerro El Cono is a 1,310-foot-tall (400 meters), pyramid-like formation in the Amazon rainforest. It rises steeply from the relatively flat jungle landscape of eastern Peru, making it visible from as far west as the Andes — 250 miles (400 kilometers) away — on a clear day.

The formation, whose name translates to "cone hill," is located in a mountainous region on the border between Peru and Brazil known as the Sierra del Divisor. The mountains are visible in the background of most photographs of Cerro El Cono, but the formation is isolated from the other peaks and has an unusual pyramidal shape, making it stand out from the rest of the mountain range.

The origins of the strange peak have remained mysterious due to its remote location. While some sources suggest that the cone could be an extinct volcano, others say it might simply be an unusual rock formation.

Related: Mount Roraima: The 'lost world' isolated for millions of years that Indigenous people call the 'house of the gods'

Indigenous people have another explanation for the bizarre mountain: According to the Peruvian newspaper La República, Cerro El Cono is a spiritual entity for local tribes and groups, some of which revere the peak as an "Andean Apu" — a sacred mountain god or spirit. In the mythologies of Peru, Bolivia and Ecuador, Apus emerged from Earth to guide and protect the people living close by.

A fourth explanation — one for which there is no evidence — is that Cerro El Cono sits on the ruins of a pyramid built by ancient Indigenous tribes, according to La República.

Cerro El Cono stands adjacent to the Ucayali River, which is a major tributary of the Amazon River. The surrounding jungle is a biodiversity hotspot and home to several vulnerable species, including giant armadillos (Priodontes maximus), jaguars (Panthera onca) and various types of monkeys, according to The Guardian. The peak itself is forested and forms part of a large area that has been considered a biodiversity conservation priority since the 1990s.

Concern that this ecosystem may become degraded by infrastructure, illegal logging and gold mining prompted the creation of the Sierra del Divisor National Park in 2015. But recent surveys indicate that the protected park, which is 1.5 times the size of Yellowstone National Park, has not removed threats from illegal deforestation and wildlife poaching.

Discover more incredible places, where we highlight the fantastic history and science behind some of the most dramatic landscapes on Earth.

The green anaconda has long been considered one of the Amazon's most formidable and mysterious animals. Our new research upends scientific understanding of this magnificent creature, revealing it is actually two genetically different species. The surprising finding opens a new chapter in conservation of this top jungle predator.

Green anacondas are the world's heaviest snakes, and among the longest. Predominantly found in rivers and wetlands in South America, they are renowned for their lightning speed and ability to asphyxiate huge prey then swallow them whole.

My colleagues and I were shocked to discover significant genetic differences between the two anaconda species. Given the reptile is such a large vertebrate, it's remarkable this difference has slipped under the radar until now.

Conservation strategies for green anacondas must now be reassessed, to help each unique species cope with threats such as climate change, habitat degradation and pollution. The findings also show the urgent need to better understand the diversity of Earth's animal and plant species before it's too late.

An impressive apex predator

Historically, four anaconda species have been recognised, including green anacondas (also known as giant anacondas).

Green anacondas are true behemoths of the reptile world. The largest females can grow to more than seven meters long and weigh more than 250 kilograms.

The snakes are well-adapted to a life lived mostly in water. Their nostrils and eyes are on top of their head, so they can see and breathe while the rest of their body is submerged. Anacondas are olive-coloured with large black spots, enabling them to blend in with their surroundings.

The snakes inhabit the lush, intricate waterways of South America's Amazon and Orinoco basins. They are known for their stealth, patience and surprising agility. The buoyancy of the water supports the animal's substantial bulk and enables it to move easily and leap out to ambush prey as large as capybaras (giant rodents), caimans (reptiles from the alligator family) and deer.

Green anacondas are not venomous. Instead they take down prey using their large, flexible jaws then crush it with their strong bodies, before swallowing it.

As apex predators, green anacondas are vital to maintaining balance in their ecosystems. This role extends beyond their hunting. Their very presence alters the behaviour of a wide range of other species, influencing where and how they forage, breed and migrate.

Anacondas are highly sensitive to environmental change. Healthy anaconda populations indicate vibrant ecosystems, with ample food resources and clean water. Declining anaconda numbers may be harbingers of environmental distress. So knowing which anaconda species exist, and monitoring their numbers, is crucial.

To date, there has been little research into genetic differences between anaconda species. Our research aimed to close that knowledge gap.

Untangling anaconda genes

We studied representative samples from all anaconda species throughout their distribution, across nine countries.

Our project spanned almost 20 years. Crucial pieces of the puzzle came from samples we collected on a 2022 expedition to the Bameno region of Baihuaeri Waorani Territory in the Ecuadorian Amazon. We took this trip at the invitation of, and in collaboration with, Waorani leader Penti Baihua. Actor Will Smith also joined the expedition, as part of a series he is filming for National Geographic.

We surveyed anacondas from various locations throughout their ranges in South America. Conditions were difficult. We paddled up muddy rivers and slogged through swamps. The heat was relentless and swarms of insects were omnipresent.

We collected data such as habitat type and location, and rainfall patterns. We also collected tissue and/or blood from each specimen and analysed them back in the lab. This revealed the green anaconda, formerly believed to be a single species, is actually two genetically distinct species.

The first is the known species, Eunectes murinus, which lives in Perú, Bolivia, French Guiana and Brazil. We have given it the common name "southern green anaconda". The second, newly identified species is Eunectes akayima or "northern green anaconda", which is found in Ecuador, Colombia, Venezuela, Trinidad, Guyana, Suriname and French Guiana.

We also identified the period in time where the green anaconda diverged into two species: almost 10 million years ago.

The two species of green anaconda look almost identical, and no obvious geographical barrier exists to separate them. But their level of genetic divergence — 5.5% — is staggering. By comparison, the genetic difference between humans and apes is about 2%.

Preserving the web of life

Our research has peeled back a layer of the mystery surrounding green anacondas. This discovery has significant implications for the conservation of these species — particularly for the newly identified northern green anaconda.

Until now, the two species have been managed as a single entity. But each may have different ecological niches and ranges, and face different threats.

Tailored conservation strategies must be devised to safeguard the future of both species. This may include new legal protections and initiatives to protect habitat. It may also involve measures to mitigate the harm caused by climate change, deforestation and pollution — such as devastating effects of oil spills on aquatic habitats.

Our research is also a reminder of the complexities involved in biodiversity conservation. When species go unrecognised, they can slip through the cracks of conservation programs. By incorporating genetic taxonomy into conservation planning, we can better preserve Earth's intricate web of life — both the species we know today, and those yet to be discovered.

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

Climate change could be gradually making the world's tropical rainforests too hot for photosynthesis to occur, and it may eventually trigger their collapse, a new study has warned. 

Using data collected from the International Space Station (ISS), scientists found that a small yet growing percentage of tree leaves in tropical forests are approaching the maximum temperature threshold for leaves to photosynthesize. 

The average critical temperature beyond which photosynthetic machinery in tropical trees begins to fail is 116 degrees Fahrenheit (46.7 degrees Celsius). Currently, only 0.01 % of all leaves surpass this critical temperature every year. But scientists warn that air temperature rises of 7.2 F (4 C) could push trees in tropical forests beyond a tipping point and into mass death. 

Related: Amazon nears 'tipping point' where rainforest could transform into savanna

If this were to happen, it would spell disaster for Earth's climate systems and biodiversity, researchers report in a study published Wednesday (Aug. 23) in the journal Nature.

"It's concerning from our perspective that you see nonlinear trends. So you heat the air by, let's say, 2, 3 degrees Celsius [3.6 to 5.4 F], and the actual upper temperature of these leaves goes up by 8 degrees [Celsius; 14.4 F]," Christopher Doughty, an associate professor of ecoinformatics at Northern Arizona University, said during a press conference on Monday (Aug. 21). "Even though a small percentage of leaves are currently doing this, our best guess is that a 4 degrees Celsius increase in temperature could cause some serious issues for certain tropical forests."

How to take a rainforest's temperature

Tropical rainforests are vital regions for our planet. They encompass 3 billion acres (1.2 billion hectares), or around 6%, of Earth's surface area, and are home to half of the world's animal and plant species. They are also vital stores of the world's fresh water — with the Amazon Basin alone storing one-fifth. Photosynthesis in rainforests produces 32% of the planet's oxygen and helps stabilize global climates by sucking billions of tons of carbon dioxide from the atmosphere each year.

To build up a picture of the temperatures in the world's tropical forests, the researchers turned to the Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) sensor on the ISS.

The scientists combined ECOSTRESS temperature readings from 2018 to 2020 with thousands of ground measurements made from infrared-sensing pyrgeometers in rainforests across South America, Central Africa and Southeast Asia.

Aggregating these results revealed that canopy temperatures peaked at around 93.2 F (34 C) on average, and a small proportion exceeded 104 F (40 C). Moreover, every season, 0.01% of leaves exceeded a critical temperature beyond which their photosynthesis is likely to shut down, resulting in their deaths.

This number may sound inconsequential, but the researchers noted it could increase rapidly. "While the number is small it has large implications — it's not going to go 0.01 to 0.02. It's going to jump nonlinearly, it's going to increase potentially much faster," Joshua B. Fisher, an associate professor of environmental science at Chapman University in California said at the press conference.

By performing laboratory leaf experiments at 3.6, 5.4 and 7.2 F (2, 3 and 4 C) of warming, the researchers found that temperatures around some of the leaves peaked much higher than the air temperature — by up to 14.4 F (8 C).

Plugging these peak temperatures into a mathematical model, the scientists found that an average 7 F (3.9 C) increase in the air temperature surrounding the leaves caused those most exposed to the heat to have their water-carrying stomata closed off by the tree, leading to their deaths. This triggered a cascade effect, increasing the temperature around the remaining leaves and potentially killing them, their branches and the trees in turn.

"If you have 10% of the leaves dying, the whole branch is going to be warmer because a critical part of that branch can no longer cool the broader branch. Likewise you can make that assumption across the whole forest when a tree dies," Doughty said.

Yet in spite of their findings, the scientists are optimistic that humanity has enough time to curb emissions and avoid potential tipping points in tropical forests.

"This is a glimpse into a potential tipping point. It is not saying that the tropical forests are now going to be savannas tomorrow," Fisher said. "If you think about human health, you want to know if you're sick or have cancer so you can deal with it before it takes over."

Incredibly rare footage of a fight between a sloth and an ocelot has been captured deep in the Amazon rainforest.

Sloths are better known for their super-slow lifestyles than their fighting prowess — the common name "sloth" is derived from the Old English for "laziness." They clamber through the trees of Central and South American rainforests slowly and deliberately, taking their time as they pluck the leaves, fruits and insects they feed on. Sloths are so slow that algae grows in their fur and moths lay their eggs on them.

But the recent footage, captured by primate researchers in the Yasuní Biosphere Reserve in eastern Ecuador, indicates that sloths are not total doormats. The team, studying monkeys, had set up camera traps around a mineral lick — an area of exposed substrate that is frequented by rainforest animals in need of nutrients not otherwise available in their diets.

"It's as pristine of a place as you’ll find in the western Amazon," co-author Anthony Di Fiore, a biologist at the University of Texas at Austin, told Live Science.

Their motion-triggered cameras captured video of a Linnaeus’s two-toed sloth (Choloepus didactylus) defending itself against an ocelot (Leopardus pardalis) attack. The researchers described their findings in the September edition of the journal Food Webs.

Mineral licks are dangerous spaces. They provide essential nutrients — but at a cost. Arboreal animals such as sloths, monkeys and porcupines have to risk being on the ground to get to the minerals.

There, predators may lie in wait. Previous research has shown that jaguars and pumas stake out mineral licks in the hopes of easy access to prey animals. In this case, an ocelot, a small cat native to South America, attempted to prey on a sloth trying to get its vitamins.

This mineral lick is unusually visible, enabling the researchers to capture uniquely clear footage. "It's a more open area," Di Fiore noted. The other licks in the region are secluded, in caves or along river banks.

Related: Jaguar kills another predatory cat in never-before-seen footage

Ocelots have been recorded preying on sloths before — though observations of both mammals are scarce due to their secretive lifestyles. Sloths and ocelots are largely nocturnal, though this recent footage occurred during daylight hours. In the video, the ocelot attempts to bite the back of the sloth’s neck — a strategy typical of the species. A previous study of sloth predation by an ocelot demonstrated that the cats tend to target the back of the skull.

But in this case the sloth pries itself from the jaws of its predator, rolls onto its back and swipes at it with its formidable set of claws. It then clambers onto a log spanning the pool filling the mineral lick. The ocelot follows, attempting to dislodge its dangling prey. Then, the footage ends, due to the inability of the stationary cameras to follow the exchange.

The brief footage provides a window into the little-known habits of these elusive species. "We have not picked up any other evidence of predation, or attempted predation in the tens of thousands of pictures and videos that we've gotten," Di Fiore said.

Though ocelots have been known to eat sloths, they are not a staple. Rare observations like this one help to shed more light on the behaviors of the rarely seen species.

"It's hard to get a grip on their natural history," Di Fiore said. But camera traps are "one one way to do that: taking advantage of the fact that you're not there, scaring them away. These things that we don't know about are going on right under our noses."

Earth's ecosystems may be careering toward collapse much sooner than scientists thought, a new study of our planet's warming climate has warned.

According to the research, more than a fifth of the world's potentially catastrophic tipping points — such as the melting of the Arctic permafrost, the collapse of the Greenland ice sheet and the sudden transformation of the Amazon rainforest into savanna — could occur as soon as 2038. 

In climatology, a "tipping point" is the threshold beyond which a localized climate system, or "tipping element," irreversibly changes. For instance, if the Greenland ice sheet were to collapse, it would also reduce snowfall in the northern part of the island, making large parts of the sheet irretrievable. 

Yet the science behind these dramatic transformations is poorly understood and often based on oversimplified models. Now, a new attempt to understand their inner workings, published June 22 in the journal Nature, has revealed that they may happen much sooner than we thought. 

Related: Could climate change make humans go extinct?

"Over a fifth of ecosystems worldwide are in danger of collapsing," co-author Simon Willcock, a professor of sustainability at Bangor University in the U.K., said in a statement. "However, ongoing stresses and extreme events interact to accelerate rapid changes that may well be out of our control. Once these reach a tipping point, it's too late."

Unlike the well-established link between the burning of fossil fuels and climate change, the study of tipping points is a young and contentious science. 

To understand how rising temperatures and other environmental stressors could cause complex ecosystems to break down, scientists use computer models to simplify ecosystems' dynamics, enabling them to predict the fate of those ecosystems — and when their tipping points could be reached.

But if these simulations miss an important element or interaction, their forecasts can land decades off the mark. For example, the Intergovernmental Panel on Climate Change (the United Nations' most important body for evaluating climate science) said in its most recent report that the Amazon rainforest could reach a tipping point that will transform it into a savannah by 2100. 

The researchers behind the new study say this prediction is too optimistic.

According to the researchers, most tipping-point studies build the math in their models to focus on one predominant driver of collapse, for example deforestation in the Amazon rainforest. However, ecosystems aren't contending with just one problem but rather a swarm of destabilizing factors that compound one another. For example, the Amazon also faces rising temperatures, soil degradation, water pollution and water stress.

To investigate how these elements interact and whether these interactions can, in fact, hasten a system's demise, the scientists behind the new study built computer models of two lake and two forest ecosystems (including one which modeled the collapse of civilization on Easter Island) and ran them more than 70,000 times while adjusting the variables throughout.

After testing their systems across multiple modes — with just one cause of collapse acting, with multiple causes acting and with all of the causes plus the introduction of random noise to mimic fluctuations in climate variables — the scientists made some troubling findings: multiple causes of collapse acting together brought the abrupt transformation of some systems up to 80% closer to the present day.

And even when the main cause of collapse was not allowed to increase with time, 15% of the collapses occurred purely because of the new elements.

"Our main finding from four ecological models was that ecosystems could collapse 30-80% earlier depending on the nature of additional stress," co-author John Dearing, a professor of physical geography at Southampton University in the U.K. told Live Science in an email. "So if previous tipping points were forecast for 2100 (i.e. 77 years from now) we are suggesting these could happen 23 to 62 years earlier depending on the nature of the stresses."

This means that significant social and economic costs from climate change might come much sooner than expected, leaving governments with even less time to react than first thought.

"This has potentially profound implications for our perception of future ecological risks," co-author Gregory Cooper, a climate systems researcher at the University of Sheffield in the U.K., said in the statement. "While it is not currently possible to predict how climate-induced tipping points and the effects of local human actions on ecosystems will connect, our findings show the potential for each to reinforce the other. Any increasing pressure on ecosystems will be exceedingly detrimental and could have dangerous consequences."

Millions of lasers shot from a helicopter flying over the Amazon basin have revealed evidence of unknown settlements built by a "lost" pre-Hispanic civilization, resolving a long-standing scientific debate about whether the region could sustain a large population, a new study finds.

The findings indicate the mysterious Casarabe people — who lived in the Llanos de Mojos region of the Amazon basin between A.D. 500 and 1400 — were much more numerous than previously thought, and that they had developed an extensive civilization that was finely adapted to the unique environment they lived in, according to the study, published online Wednesday (May 25) in the journal Nature.

The study researchers used airborne lidar — "light detection and ranging," in which thousands of infrared laser pulses are bounced every second off the terrain to reveal archaeological structures beneath dense vegetation — and discovered several unknown settlements within a network of roads, causeways, reservoirs and canals that was centered on two very large Casarabe settlements, now called Cotoca and Landívar.

"In one hour of walking, you can get to another settlement," study lead author Heiko Prümers, an archaeologist at the German Archaeological Institute in Bonn, told Live Science. "That's a sign that this region was very densely populated in pre-Hispanic times." Prümers and his colleagues have studied the Casarabe ruins in the region, now part of Bolivia, for more than 20 years.

Related: Archaeologists find vast network of Amazon villages laid out like the cosmos

Ancient landscape

The Llanos de Mojos region is a lowland tropical savanna in the southwest of the Amazon basin. It has distinct wet and dry seasons each year — the driest months have no rain, but during the rainy season between November and April much of the area is flooded for months at a time.

Spanish missionaries in the 16th century found only isolated communities living there, and scientists had supposed that the area's pre-Hispanic population was the same, Prümers said. Earthworks were found in the 1960s, but many scientists disputed whether they were ruins or natural features.

But the latest discoveries finally refute the idea that the region was sparsely populated, and show that the Casarabe people had instead instituted a "low-density tropical urbanism" across a vast area, he said.

Smaller Casarabe settlements could have been home to thousands of people, and 24 are now known — nine of them were found for the first time in the recent lidar study, Prümers said.

The settlements were joined by roads and causeways, and had been built in roughly concentric circles around the two major Casarabe sites at Cotoca and Landívar; both were known of before, but their true extent has only now been revealed by lidar, he said.

Cotoca and Landívar were each centered on ceremonial sites that had huge raised platforms of earth, topped by enormous pyramids. The religious beliefs of the Casarabe people are unknown, but the study reveals the platforms and pyramids were orientated to the north-northwest — the same direction as the Casarabe burials that have been found. "So there must've been a 'world view' but nothing is known about that," Prümers said.

Lost civilization

An unusual feature of the settlements is that the Casarabe built them within a massive infrastructure of canals and reservoirs for the management of water. 

Along with roads and causeways, these waterways radiated out in all directions from the major settlements like Cotoca and represented a major investment in landscape management and labor mobilization, the researchers wrote in the study.

Prümers said the system may have been used to control the seasonal flooding of the region, to allow the farming of maize and other crops in raised areas; and it's possible some reservoirs were used to farm fish, which would have been an important source of protein for the Casarabe people.

And he speculates that water scarcity may have played a role in the demise of the Casarabe civilization in about A.D. 1400, more than 100 years before the arrival of the Spanish. It's possible that because the water management system relied so heavily on the floods or other sources of water that it — and the civilization that relied on it — fell apart during a prolonged dry period due to a changing climate, he said.

Michael Heckenberger, an anthropologist at the University of Florida, who wasn't involved in the research but who has extensively studied the archaeology of the region, said the findings verify that the Casarabe people were organized into a type of low-density urbanism. "The archaeology, chronology and dating are extremely well-described and locked down," he said. 

He notes that similar civilizational structures have now been found in other tropical regions that were once thought to be unsuitable for ancient civilizations, such as among the Maya in pre-Hispanic Mesoamerica.

What's more, the use of lidar to reveal the extent of the archaeological record in such regions is a major advance. "Lidar is able to create a really clear synthetic picture of what a full-scale urbanized Amazonian landscape might look like," Heckenberger told Live Science. "That is a truly remarkable achievement."

Originally published on Live Science.

If deforestation continues, the Amazon rainforest could reach a critical tipping point where most of it transforms into a dry savanna, a new study warns. 

The study, published Monday (March 7) in the journal Nature Climate Change, suggests that more than 75% of the rainforest has steadily lost "resilience" since the 2000s, meaning those portions of the rainforest now can't recover as easily from disturbances, such as droughts and wildfires. Regions of the rainforest that show the most profound losses in resilience are located near farms, urban areas and areas used for logging, Inside Climate News reported.  

Climate change, rampant deforestation and burnings conducted for agriculture and ranching have left the Amazon far warmer and drier than in decades past, and since 2000, the region has endured three major droughts, The New York Times reported. 

Related: 10 signs that Earth's climate is off the rails 

By examining satellite images taken between 1991 and 2016, the researchers determined how long the rainforest took to bounce back after such events, The Guardian reported. The researchers determined that, since the turn of the 21st century, the rainforest has been taking longer and longer to recover biomass, meaning the mass of living trees and other vegetation, after droughts and fires.  

"That lack of resilience shows that, indeed, there is only so much of a beating that this forest can take," Paulo Brando, a tropical ecologist at the University of California, Irvine who was not involved in the study, told The New York Times. 

The new study adds to existing evidence that the world's largest rainforest is hurtling toward a tipping point, beyond which large swaths of the forest could suddenly die off. The study cannot pinpoint when this tipping point might be reached, but the forest could hit it within decades, the study authors told Inside Climate News. 

If the rainforests surpasses this tipping point, the ecosystem could swiftly change into a vast savanna, unleashing tens of billions of tons of carbon dioxide during the transformation, The Guardian reported.

That said, some scientists don't agree with the use of the term "tipping point" in this context, according to Inside Climate News. 

"It's sort of a mischaracterization that the scientists are certain that the Amazon is going to die" and that, in a snap, the whole forest could suddenly be lost, Scott Denning, a climate scientist at Colorado State University, told Inside Climate News. While Denning doesn't agree with this description of the situation, he said there's ample evidence that large portions of the forest are in rapid decline, particularly along the southern and eastern margins that have been ravaged by deforestation.

"It's not bouncing back. It's letting carbon out. It's drying out. It's dying," he said.

At this point, can anything be done to prevent the Amazon rainforest from turning into the Amazon savanna? Experts say there is.

"These systems are highly resilient, and the fact that we have reduced resilience doesn't mean that it has lost all its resilience," Brando told the Times. "If you leave them alone for a little bit, they come back super strongly."

But it requires key steps to be taken, experts said.

"We have to get to zero deforestation, zero forest degradation," Carlos Nobre, a senior scientist at the National Institute of Amazonian Research in Brazil, who was not involved in the study, told the Times. "We still have a chance to save the forest."

Originally published on Live Science. 

Although rainforests cover only a small percentage of Earth's total surface area, they're home to half of the world's plant and animal species. As the name suggests, rainforests are also very wet: They receive more than 70 inches (178 centimeters) of rain each year, on average.

There are many types of rainforests, but they can be split into two general categories: tropical and temperate. Tropical rainforests are hot, lush forests located close to the equator, while the rarer temperate rainforests are found farther north or south of the equator, near coastal areas, according to the NASA Earth Observatory. All of the biggest rainforests on Earth fall into the former category, but we've included the largest temperate rainforest as an honorable mention.

It's tricky to compare rainforest sizes because where they start and finish is not always clear; a single forest can span several countries and may be broken up. Rainforest sizes also fluctuate over time due to climate change and deforestation. There's no doubt about the largest and second-largest rainforests on this list, but the remaining two are based on estimates and expert opinion.

4. Sundaland rainforest

The Sundaland rainforest is the fourth-biggest rainforest in the world, at about 197,000 square miles (510,000 square km), according to Mongabay, a nonprofit news website for environmental science and conservation. The rainforest includes the Malay Peninsula on mainland Southeast Asia and the nearby islands of Sumatra, Java and Borneo. It spans Indonesia, Malaysia, Brunei, Thailand and Singapore.

The Sundaland rainforest is home to many species, including orangutans, Bornean rainbow toads (Ansonia latidisca) and corpse flowers (Rafflesia arnoldi), the world's largest flower. Indonesia's primary rainforest has declined by more than 37,000 square miles (97,000 square km) since 2001, according to data from Global Forest Watch, a nonprofit that monitors forests around the world. Nonetheless, Elizabeth Goldman, a research manager for Global Forest Watch at World Resources Institute, told Live Science she considers the country one of the brighter spots when it comes to deforestation.

"Historically, there has been a lot of commercial oil palm plantation establishment or timber extraction," Goldman said. But in recent years, she added, "we've seen decreasing primary forest loss in Indonesia and Malaysia." The Indonesian government has been very active in trying to reduce deforestation, especially since the country was badly affected by fires in 2015, she added.

3. New Guinea rainforest

The third-largest continuous rainforest in the world is on the island of New Guinea, which is split into two countries: The eastern half is part of Papua New Guinea, and the western half belongs to Indonesia. This island covers about 303,000 square miles (786,000 square km) and is home to at least 5% of the world's plant and animal species, including tree kangaroos and crowned pigeons, according to the WWF.

The New Guinea rainforest can also be mapped to include the forests of northern Australia as they were once connected; New Guinea and Australia became separated by ocean about 11,700 years ago, according to the Australian government's Geoscience Australia website.

Commercial logging and agriculture are rapidly deforesting New Guinea. The process usually starts with selective logging of commercially valuable timber, with the area then more likely to be converted to industrial plantations to grow crops such as oil palm trees, according to Mongabay.

2. Congo Basin

The Congo Basin rainforest in Central Africa is the second-largest rainforest, spanning more than 780,000 square miles (2 million square km), according to the WWF. The rainforest encompasses six countries in West and Central Africa: Cameroon, Equatorial Guinea, Gabon, the Central African Republic, the Republic of the Congo and the Democratic Republic of the Congo (DRC). The DRC has more than 383,000 square miles (992,000 square km) of primary rainforest — more than any other country except Brazil, according to Global Forest Watch data.

Gorillas, forest elephants and thousands of other species call the Congo rainforest home. Many of these species, such as bonobos (Pan paniscus) and okapi (Okapia johnstoni), are found nowhere else on Earth. The Congo Basin is threatened by deforestation, primarily for agriculture. In contrast to the industrial agriculture deforestation in the Amazon, the Congo rainforest is typically cut down for smaller-scale agriculture — for example, by subsistence farmers who grow food to feed their families or to supply local markets, Goldman said.

"It's often cultivated for a few years until soil nutrients are depleted, and then it's left fallow for a number of years," Goldman said. "And oftentimes, the forest will actually come back as secondary forest and then will get cut again. So you see this shifting cycle of loss and regrowth in those areas." The forest is also threatened by expanding urban areas, mining and industrial logging, according to Mongabay.

1. Amazon rainforest

The Amazon rainforest in South America is, by far, the largest rainforest in the world. It covers about 80% of the Amazon basin, which spans at least 2.3 million square miles (6 million square kilometers), according to the NASA Earth Observatory. That's more than half the size of the U.S. and three times bigger than the next-largest rainforest. The Amazon is spread across nine countries in South America: Brazil, Peru, Colombia, Ecuador, Bolivia, Venezuela, Guyana, French Guiana and Suriname.

According to the WWF, the forest includes at least 10% of Earth's total biodiversity, or variety of plants, animals and other living things. This includes many species, such as sloths, harpy eagles (Harpia harpyja), Brazil nut trees (Bertholletia excelsa) and jaguars (Panthera onca).

Brazil has the largest chunk of the Amazon rainforest, with more than 1.2 million square miles (3.11 million square km) of primary rainforest. These are mature forests that haven't been disturbed in recent times. However, that forest is rapidly deteriorating; Brazil is also the No. 1 country for forest loss, with a decline of more than 100,000 square miles (260,000 square km) since 2001, according to data from Global Forest Watch.

"A lot of this is due to agricultural expansion," Goldman said. "Fires will be set to clear land, and oftentimes, those fires will escape into neighboring forests."

Amazon clearing is typically for larger-scale industrial agriculture — for example, for growing animals such as cattle and crops like soy, according to Goldman. Fires contribute to climate change, which causes the forests to become hotter and drier. That makes them more flammable, thus creating a destructive feedback loop. Data from the World Wildlife Foundation suggests that nearly 20% of the Amazon forest has been completely destroyed, and more of the forest has been degraded.

Related: The Amazon rainforest is officially creating more greenhouse gases than it is absorbing

Honorable mention: Tongass National Forest

The largest temperate rainforest in the world is the Tongass National Forest in Alaska. It is much smaller than any of the tropical rainforests on this list, at about 26,250 square miles (68,000 square km), according to the U.S. Department of Agriculture (USDA). Temperate rainforests cover less land than tropical rainforests and are found in cooler climates, usually next to oceans.

Stretching along the coastline of southeast Alaska, the Tongass National Forest is home to wildlife such as salmon, brown bears (Ursus arctos), black bears (Ursus americanus) and bald eagles (Haliaeetus leucocephalus). The Tongass National Forest has declined over the past century due to logging and continues to be threatened by it today, according to the National Audubon Society, a nonprofit bird and habitat conservation organization. The forest is also vulnerable to climate change and threatened by drought, according to the USDA.

More than 100 world leaders have agreed to a commitment to halt and reverse deforestation by 2030, in the first major deal of the 2021 U.N. Climate Change Conference (COP26) in Glasgow, Scotland. 

The commitment, called the Glasgow Leaders' Declaration on Forest and Land Use encompasses 85% of the world's forests and offers $19.2 billion in public and private funding to end both the legal and illegal destruction of forestland. 

Leaders such as President Joe Biden, China's Xi Jinping and Brazil's Jair Bolsonaro have signed on to the deal. But the signatories have not yet determined how the commitment will be enforced, leaving scientists to warn that previous legally nonbinding deforestation deals — such as the 2014 New York Declaration on Forests, which pledged to halve deforestation by 2020 and end it by 2030 — failed to meet their objectives.

Related: The world has a serious deforestation problem. These 7 images prove it.

"It is good news to have a political commitment to end deforestation from so many countries and significant funding to move forward on that journey," Simon Lewis, a professor of global change science at University College London, told the BBC. But he added that the world "has been here before" with the 2014 declaration, "which failed to slow deforestation at all." 

Jo Blackman, head of forests policy and advocacy at environmental human rights NGO Global Witness, said that while the pledge's list of signatories is "impressive," it risks reiterating past failed commitments if it "lacked teeth" in the form of legal commitments.

In addition to being crucial ecosystems, forests absorb and store carbon dioxide — which makes up around 80% of the greenhouse gases that drive climate change. Deforestation and land clearing account for 23% of global human-caused greenhouse gas emissions, according to a 2019 Intergovernmental Panel on Climate Change (IPCC) report. 

The main drivers of land clearing are pasture for cattle (41%), commercial cropland to grow palm oil and soy (18%) and logging for paper and wood (13%), according to a 2019 study published in the journal Global Environmental Change.

Satellite data compiled by Global Forest Watch shows that one-third of the tropical deforestation that occurred in 2019 happened in Brazil. In fact, Brazil and Indonesia accounted for 52% of the 20,850 square miles (54,000 square kilometers) of lost forestland globally.

At the COP26 news conference, Bolsonaro said his government was committed to "eliminating illegal deforestation by 2030."

In fact, many of the Bolsonaro regime’s actions have actually made it easier to seize, cut and clear rainforest via legal means, according to Human Rights Watch. And the Amazon is already on the brink. A July 2021 study showed that the Amazon has switched from producing more carbon than it absorbs, Live Science previously reported. Another study, published in October 2020, showed that as much as 40% of the Amazon rainforest could be at a tipping point where it could transform into savanna.

Although there may be challenges ahead, reforestation successes aren't unprecedented and can be achieved. Despite the losses to precious tropical rainforest, one study using NASA satellites shows that in recent decades the world has become a visibly greener place. This is due, in large part, to efforts by China and India, which account for one-third of Earth's greening over the past 20 years; 42% of China's greening is made up of the planting of new forests and expanding old ones through programs that aim to mitigate air pollution, land degradation and climate change.

Of the pledge's new funding, $1.7 billion will be used to support Indigenous communities in protecting rainforests by securing their rights to land. According to Global Witness, of the record 227 people killed while protecting ecosystems in 2020, one-third belonged to indigenous communities.

Originally published on Live Science.

Billions of lasers shot from a helicopter flying over the Brazilian Amazon Rainforest have detected a vast network of long-abandoned circular and rectangular-shaped villages dating from 1300 to 1700, a new study finds. 

The round villages all had remarkably similar layouts, with elongated mounds circling a central plaza, like marks on a clock. 

"These latter elongated mounds, when seen from above, look like the rays of the sun, which gives them the common name of 'Sóis,'" the Portuguese word for "suns," the researchers wrote in the study.

Related: Amazon photos: Trees that dominate the rainforest 

The discovery is part of a new archaeological focus on the pre-Columbian Amazon. Within the past 20 years, researchers have learned that the rainforest's southern rim was home to a great diversity of soil-sculpting cultures that engineered the landscape before the Europeans arrived. Within the past decade, scientists have uncovered the remnants of so-called "mound villages," which are shaped as circles or rectangles, and connected by road networks. 

Archaeologists, however, had yet to look for mound villages in the Brazilian state of Acre, so an international group of researchers teamed up to survey the area with lidar — or light detection and ranging. With this technique, billions of lasers shot from overhead (in this case, from a helicopter) penetrate the rainforest's canopy and map the landscape below. 

The lidar survey, combined with satellite data, revealed a remarkable 25 circular mound villages and 11 rectangular mound villages, the researchers said. Another 15 mound villages were so poorly preserved, they could not be categorized as either circular or rectangular, the team added. 

The circular mound villages had an average diameter of 282 feet (86 meters), while the rectangular villages tended to be smaller, with an average length of 148 feet (45 m). Further analysis of the "sun" villages revealed they had carefully planned roads; each circular mound village had two "principal roads" that were wide and deep (up to 20 feet, or 6 m, across) with high banks, and smaller "minor roads" that led to nearby streams.

Most of the villages were close to each other — just about 3 miles (4.4 km) apart, the researchers found. The principal roads often connected one village to another, creating a vast community network in the rainforest, the researchers said.

The distinctive and consistent way Indigenous people arranged these villages suggests that they had specific social models for the way they organized their communities, the researchers said. It's even possible that this configuration was meant to represent the cosmos, they noted.

The intricate road system, however, "is hardly a surprise for Amazonian archaeologists," the researchers wrote in the study. "Early historical accounts attest to the ubiquity of road networks across the Amazon. They are mentioned since the 16th-century account of [the Spanish Dominican missionary] Friar Gaspar de Carvajal, who observed wide roads leading from the riverine villages to the interior." Later, in the 18th century, Col. Antonio Pires de Campos, "described a vast population inhabiting the region, with villages connected by straight, wide roads that were constantly kept clean," the researchers added. 

Little is known about the culture practiced by the people in these mound villages. But preliminary research suggests that this culture's ceramics were "cruder" than those of the culture that preceded them, known as the Geoglyphs, who lived in that region from about 400 B.C. to A.D. 950. 

The study was published in April in the Journal of Computer Applications in Archaeology, and was just featured on Channel 4's "Jungle Mystery: Lost Kingdoms of the Amazon," in the U.K., which also featured other ancient findings from the Amazon, including a sprawling, 8-mile-long 'canvas' of rock art in Colombia dating to the last ice age.

Originally published on Live Science.

An 8-mile-long "canvas" filled with ice age drawings of mastodons, giant sloths and other extinct beasts has been discovered in the Amazon rainforest. 

The gorgeous art, drawn with ochre — a red pigment frequently used as paint in the ancient world — spans nearly 8 miles (13 kilometers) of rock on the hills above three rock shelters in the Colombian Amazon, a new study finds.

"These really are incredible images, produced by the earliest people to live in western Amazonia," study co-researcher Mark Robinson, an archaeologist at the University of Exeter, who analyzed the rock art alongside Colombian scientists, said in a statement. 

Related: 10 extinct giants that once roamed North America 

Indigenous people likely started painting these images at the archaeological site of Serranía La Lindosa, on the northern edge of the Colombian Amazon, toward the end of the last ice age, about 12,600 to 11,800 years ago. During that time, "the Amazon was still transforming into the tropical forest we recognize today," Robinson said. Rising temperatures changed the Amazon from a patchwork landscape of savannas, thorny scrub and forest into today's leafy tropical rainforest.

The thousands of ice age paintings include both handprints, geometric designs and a wide array of animals, from the "small" — such as deer, tapirs, alligators, bats, monkeys, turtles, serpents and porcupines — to the "large," including camelids, horses and three-toed hoofed mammals with trunks. Other figures depict humans, hunting scenes and images of people interacting with plants, trees and savannah creatures. And, although there is also ice age animal rock art in Central Brazil, the new findings are more detailed and shed light on what these now-extinct species looked like, the researchers said.

"The paintings give a vivid and exciting glimpse into the lives of these communities," Robinson said. "It is unbelievable to us today to think they lived among, and hunted, giant herbivores, some which were the size of a small car."

Many of South America's large animals went extinct at the end of the last ice age, likely through a combination of human hunting and climate change, the researchers said. 

Excavations within the rock shelters revealed that these camps were some of the earliest human-occupied sites in the Amazon. The paintings and camps offer clues about these early hunter-gatherers' diets; for instance, bone and plant remains indicate that the menu included palm and tree fruits, piranhas, alligators, snakes, frogs, rodents such as paca and capybara, and armadillos, the researchers said.

Scientists excavated the rock shelters in 2017 and 2018, following the 2016 peace treaty between the Colombian government and FARC, a rebel guerrilla group. After the peace agreement, researchers spearheaded a project known as LastJourney, which aimed to find out when people first settled the Amazon, and what impact their farming and hunting had on the biodiversity of the region. 

"These rock paintings are spectacular evidence of how humans reconstructed the land, and how they hunted, farmed and fished," study co-researcher José Iriarte, an archaeologist at the University of Exeter, said in the statement. "It is likely art was a powerful part of culture and a way for people to connect socially."

The findings were published in April in the journal Quaternary International, and the University of Exeter released a statement today (Nov. 30) to coincide with a new TV documentary on the finding called "Jungle Mystery: Lost Kingdoms of the Amazon," which will air in the U.K. in December.

Originally published on Live Science.

To celebrate the 50th anniversary of Earth Day, Live Science asked a dozen scientists to share their favorite facts about our home planet. These researchers marveled at everything from backward flowing rivers in Antarctica to the Giant Crystal Cave of Naica in Mexico, which one geologist called the "Sistine Chapel of crystals."

Read on to learn about Earth's wonders. If you've got one of your own to share, write about it in the comments below.

1. Mountainous changes

"The top of Mount Everest is limestone from an ancient ocean floor formed 470 million years ago — before life had even left the ocean! I love this fact, because it reminds us of the tremendous changes our Earth has gone through to bring us to this moment in time, from mass extinctions to asteroid impacts and vast movements of the very ground we stand on. Just as humans are one small speck in a vast universe (thanks, Carl Sagan!), so too are we a tiny blip of time in the long arc of Earth's history," said Jacquelyn Gill, an associate professor in the School of Biology and Ecology and the Climate Change Institute at the University of Maine.

That fact can be sobering, but it provides a message of hope for our species as well. 

"When we lose species because of our actions, we're cutting threads in a tapestry that has taken billions of years to weave, and it records stories of vulnerability and loss, but of survival and resilience, too."

So while our planet's past may provide warnings of upheavals, it can also provide hints for charting the future.

"The clues to surviving global change are in the rocks, for those who can read them," Gill said.

2. Giant Crystals of Naica

Juan Manuel García-Ruiz, a geologist at the Spanish National Research Council, has spent a good portion of his career crawling into underground vaults of pure crystal. Last year, García-Ruiz authored a paper on the history of the largest geode on Earth — a jagged, crystal chamber in a Spanish mine that can comfortably fit several scientists inside at once. But his favorite spot on Earth is where the Giant Crystal Cave of Naica lays buried, about 1,000 feet (300 meters) below the town of Naica, Mexico.

"This is the 'Sistine Chapel of crystals,'" García-Ruiz told Live Science. Giant gypsum pillars, most of which are as large and thick as telephone poles, slash through the basketball-court-size cavern in a brilliant display of Earth's slow-motion alchemy. The crystals are hundreds of thousands of years old, and still actively growing in the hot, humid cave. For now, the largest one measures 39 feet (12 m) in length and 13 feet (4 m) in diameter, and it weighs 55 tons (50 metric tons).

3. Earth's mysterious synergy

"My favorite fact about Earth is that all parts of it, from the center to the atmosphere, appear to be dynamically and chemically interactive, over a wide range of time scales and spatial scales," Ed Garnero, a professor at Arizona State University's School of Earth and Space Exploration, told Live Science.

As an example of this planet-wide synchronicity, Garnero sent an image (which he made) depicting the mysterious underground structures that some researchers have labeled "the blobs." These lopsided, continent-sized mountains sit inside Earth's mantle about halfway between your feet and the center of the planet. While scientists know from seismic imaging that these blobs exist, nobody is exactly sure what they are or what they do.

One intriguing feature of the structures, Garnero said, is that plumes of exceptionally hot rock (depicted here in yellow) appear to rise off the blobs and feed certain volcanoes on the surface — essentially creating a chemical pipeline that connects the deep Earth to the high atmosphere.

"I guess an addendum to this fact is that there is SO MUCH that we do not know about Earth — from the internal structures to the climate," Garnero said. "It is an exciting time to monitor, measure and model the observations."

4. "Stained glass" diatoms

One of the most amazing facts about Earth is that "around 20-50% of the Earth's oxygen is produced by diatoms," said Sarah Webb, a biologist and associate professor of life science at Arkansas State University-Newport. 

"Diatoms are microscopic algae with a shell made of glass," Webb told Live Science in an email. Diatoms are pretty to look at, too, she said. "They look like stained glass when viewed under a microscope." 

Life as we know it wouldn't be around were it not for an abundance of lung-friendly oxygen gas in our atmosphere. Earth has been oxygenated for about 2.3 billion to 2.4 billion years, but the tiny, delicate diatoms of today likely evolved around 250 million years ago. These unicellular organisms are ubiquitous in Earth's oceans, and scientists estimate that there are more than 100,000 species of diatoms. 

5. Rivers that flow backward

Antarctica, Earth's southernmost continent, is one of the driest places on the planet. But there's a surprising amount of liquid water lurking below the continent's frozen surface that doesn't behave as you might expect.

"Beneath the ice in Antarctica there are mountain ranges where rivers flow backward and lakes [that are] the size of New Jersey," said Robin Bell, president of the American Geophysical Union and a professor at Lamont-Doherty Earth Observatory of Columbia University in Palisades, New York.

"The weight of the overlying ice makes the water flow backward while the heat of the Earth keeps the water in the subglacial rivers and lakes from turning into ice," Bell said.

Scientists discovered clues to a backward-flowing river in Antarctica's Gamburtsev Mountains after they examined the shape of the icy layer atop the hidden river; that layer aligned with the direction of the water's movement.

6. Glowing sea creatures

More than 70% of Earth is covered with water, so it's no surprise that scientists such as David Gruber find inspiration in exploring these great depths. Gruber, a presidential professor of biology at City University of New York and an explorer with the National Geographic Society, studies glowing marine animals. He snapped the above photo, which shows the first biofluorescent seahorse known to science.

"Knowing how much magic is happening beneath the sea that we've yet to even learn about yet," is Gruber's favorite Earth fact. "It's perhaps my main inspiration as a scientist that maintains my child-like curiosity."

There's so much to learn. "How we are connected to other life and what our place is on this amazing planet is still in its early stages," Gruber told Live Science.

7. Route 66

"The boundary between Earth’s mantle and core is roughly 3,000 km [about 1,865 miles] below our feet, a little less than the total length of America’s 'Mother Road,' Route 66," said Jennifer Jackson, a professor of Mineral Physics at Caltech.

Initially, researchers thought that this region was a simple interface between solid rocks and liquid iron-rich metal. But, in reality, "this remote region is almost as complex as Earth’s surface," she said. 

While it's impossible to reach this Route-66-long place in person, "geophysical and experimental studies of this distant region reveal a fascinating landscape of chemical and structural complexity that influences what's happening on Earth’s surface," Jackson said. "For example, the complex dynamics of Earth’s core-mantle boundary affects Earth’s protective geomagnetic field and the motion of tectonic plates."

8. Life on our planet

Our planet harbors magnificent life-forms, from tiny, near-invisible organisms to giant, ferocious beasts. Billions of years ago, conditions became just right for the tiniest particles to combine together and form the very first life-forms. 

These life-forms are nearly as ancient as Earth itself. "The Earth is over 4.6 billion years [old], and life has been present on the Earth continuously since at least 3.5 billion years ago," Shuhai Xiao, professor of geobiology in the Department of Geosciences at Virginia Tech. The earliest evidence for life on our planet comes from the marks these organisms left on rocks, according to a previous Live Science report.

Photosynthetic organisms called cyanobacteria were some of the earliest life-forms on our planet. Here is a photo of fossilized Cambrian mounds formed by cyanobacteria in Newfoundland, Canada.

9. Climate feedback

Another amazing feature of our planet is how various processes interact in so-called negative climate feedbacks, which act to dampen temperature changes if they get too extreme, meaning too cold or too hot, said Jonathan Overpeck, dean of the School for Environment and Sustainability at the University of Michigan. (In general, "feedbacks" occur when one process causes a change in a second process, which in turn influences the first.)

"It’s amazing how [negative] climate feedbacks have maintained a habitable planetary climate for hundreds of millions of years — right in the sweet spot of not too cold, not too warm," said Jonathan Overpeck, dean of the School for Environment and Sustainability at the University of Michigan.

On the other hand, processes known as "positive" feedbacks can make the effects of climate change worse, because they may further amplify the planet's already increasing temperatures, according to NASA.

"We need to fight climate change harder, to keep our planet habitable and flourishing," Overpeck said. "That’s what we all need to rededicate ourselves to on this 50th anniversary of the first Earth Day."

10. The past influences the future

An amazing fact is that "historical legacies often dictate how Earth will respond to modern change," said Merritt Turetsky, the director of the Institute of Arctic and Alpine Research at the University of Colorado Boulder. 

"A legacy can be thought of as [a] memory of an ecosystem with regard to past events," Turetsky said. "One example is permafrost, frozen soils that have accumulated at high latitudes over millennia. Today, permafrost soils store so much carbon — derived from ancient plants, animals and microbes that existed on the surface of our planet — that they will be a major player in how Earth responds to future climate change."

"The past often is the key to understanding our planet's future," Turetsky told Live Science.

Caption: Merritt Turetsky's team samples frozen permafrost soils in Alaska and Canada to understand how past soil types influence the ability of Arctic ecosystems to cope with modern environmental change.

11. Fascinating dimensions

Our planet is a dynamic and ever-evolving giant orb, with earthquakes shifting the rocky plates that make up its surface, volcanoes that exude fiery lava from the planet's innards, and even deep-sea hydrothermal vents that gurgle out sizzling mineral water that supports bizarre forms of life. All of this can be enchanting to scientists who immerse themselves in the planet's geology.

Glacial geologist Johann Philipp Klages said his favorite aspects of Earth are "its fascinating dimensions and unexpected forces, which pleasantly tell us, again and again, how small and insignificant we are in the context of Earth's history." 

Klages is a research scientist in the Marine Geology section of the Alfred Wegener Institute Helmholtz Center for Polar and Marine Research in Bremerhaven, Germany. An expedition on the institution's icebreaker RV Polarstern took Klages to the Amundsen Sea Embayment in West Antarctica in 2017, where he captured this gorgeous image of the ship in front of the Pine Island ice shelf edge.

12. Natural healing

What is Earth's greatest feature? That "it supports life!" Marcia Macedo, an associate scientist and director of the Water Program at Woods Hole Research Center (WHRC) in Massachusetts, told Live Science.

"What amazes me is that most natural systems have the capacity to heal themselves after big disturbances," she said. "This is as true for a human body recovering from disease as it is for a tropical forest growing back after an intense fire."

Macedo added, "sometimes that healing is facilitated by surprising heroes," such as the tapir, which can restore degraded forests in the Amazon. The tapir does this by munching on fruit from healthy trees and then depositing their seeds in areas that have been previously burned, according to a WHRC statement and a recent webinar presentation by Macedo.

Editor's note: This caption of fact nine was updated at 11:15 am E.DT. to note that the animal is an elk, not a moose. Also, fact nine was fixed to clarify the difference between negative and positive climate feedback.

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Originally published on Live Science. 

Mysterious geoglyphs and a host of other earthworks in the Amazon rainforest suggest that the now-sparsely populated region was home to up to 1 million people before the arrival of Columbus, a new study finds.

The Amazon, the world's biggest river basin, contains the largest rainforest on Earth, covering about 2.6 million square miles (6.7 million square kilometers) across nine countries. This area, known as Amazonia, has an extraordinary array of life, harboring 1 in 10 known species in the world and 1 in 5 of Earth's birds.

Amazonia is often thought of as pristine nature, but over the past few decades, archaeologists have discovered evidence of numerous large, complex societies that may have inhabited Amazonia before the arrival of Columbus. Although these newfound discoveries contrast with the small Amazonian societies anthropologists studied in the 20th century, they are in line with initial eyewitness accounts of Europeans from the 16th and 17th centuries. [Aerial Photos of Mysterious Amazon Earthworks]

For example, previous research excavated large earthworks along the southern rim of the Amazon rainforest. These included mysterious geometrical structures known as geoglyphs that combined square, circular and hexagonal earthworks.

"The geoglyphs are interesting for several reasons," said study lead author Jonas Gregorio de Souza, an archaeologist at the University of Exeter in England."Despite the impressive architecture of these features, and the effort and planning that must have been involved in their construction, archaeologists have actually found very few remains of habitation inside the enclosures. That means they were probably not settlements, and the most likely explanation is that they were used for ceremonial gatherings, although their exact function is still a mystery."

The earthworks that scientists have found so far in the southern rim of Amazonia are typically far apart from each other. However, this region was occupied by peoples that shared common lifestyles, suggesting the earthworks might have actually formed a chain about 1,100 miles (1,800 kilometers) long.

To see how widespread human settlements were in the Amazon, scientists focused on the basin of the upper reaches of the Tapajós River, a major tributary of the Amazon. They concentrated on this area because of the dearth of archaeological research in this previously uncharted region.

The researchers used satellite images to discover 81 new archaeological sites in the upper Tapajós basin with a total of 104 earthworks. This suggests there is no gap in the network of earthworks spanning across Amazonia's southern rim, they said.

"We filled the last piece of a puzzle in Amazonian archaeology," de Souza told Live Science. "Thanks to our research in the Upper Tapajós river, now we can speak of a whole 1,800-kilometer [1,100-mile] stretch of rainforest occupied by these earth-builders."

The scientists then conducted ground surveys of 24 of these sites. "When you go to the field, not everything is like you planned," de Souza said. "In this region, the greatest difficulty is access. The distances involved are huge, and you may not always get permission from the land owners to get in, if you are lucky enough to be able to speak to them. Some very interesting earthworks we saw on the satellite imagery could not be visited because we were not granted access, though in general, people were very nice to us."

The researchers unearthed evidence, such as ceramics, polished stone axes, garbage dumps and soil rich in charcoal, that the sites they visited were once inhabited.

These sites dated to A.D. 1250 to 1500, and ranged from about 100 to 1,300 feet (30 to 400 meter) wide, mostly found on relatively flat landscapes with gentle hills. The smallest had circular ditches, often with interruptions suggestive of an entrance. The largest were typically hexagonal fortified settlements, suggesting a certain degree of planning and uniformity in their construction, with multiple mounds around circular plazas, as well as sunken roads radiating in many directions and stretching for up to 0.87 miles (1.4 km).

Based on the size and distribution of the earthworks, the researchers suggested that similar settlements may have extended over about 154,000 square miles (400,000 square kilometers) of the southern rim of the Amazon, supporting a population of between 500,000 and 1 million people in late pre-Columbian times.

The scientists plan more excavations in the upper Tapajós basin to refine their understanding of the cultural developments there "and how they compare to similar sites in the surroundings," de Souza said. "For example, what were the functions of different types of sites? Was the whole region occupied by a single culture? Were there different peoples established in the area in different time periods? In the case of the most elaborate earthworks, were they built all at once or were they gradually enlarged over the centuries?"

However, the new study doesn't mean Amazonia was ever a teeming megalopolis, de Souza said.

"People may misinterpret our results as indicating that the entirety of Amazonia was very densely settled in the past, and that environmental impact by pre-Columbian peoples was enormous, with not a single patch of pristine forest left standing," de Souza said. "This may have been the case in some regions where archaeologists have now uncovered evidence of extensive pre-Columbian occupation, but the truth is that most of the Amazon is uncharted. Only when more research like ours is done in parts of the basin which are still unexplored we will have an adequate understanding of how pre-Columbian populations were distributed across Amazonia."

The scientists detailed their findings online March 27 in the journal Nature Communications. The project was funded in part by National Geographic and by the European Research Council project Pre-Columbian Amazon-Scale Transformations, and was coordinated by José Iriarte at the University of Exeter.

Original article on Live Science.

A rare, vivid green bird with radiant yellow head feathers is actually a unique hybrid species that lives in the Amazon rainforest, researchers have found.

The small, golden-crowned manakin was first discovered in Brazil in 1957, but then it was not seen again until its rediscovery 45 years later in 2002. A new study of the bird's origins shows that the golden-crowned manakin is a cross between the snow-capped manakin and the opal-crowned manakin, representing the first hybrid-bird species found to date, according to a statement from the University of Toronto.

"While hybrid plant species are very common, hybrid species among vertebrates are exceedingly rare," Jason Weir, senior author of the study, said in the statement. [In Photos: Amazing Amazon Animal 'Selfies']

Hybridization occurs when two species interbreed to produce a third. While the three related species of manakins all have radiant yellow-green upper bodies with golden undersides, each has distinctively colored feathers on their head.

Although hybridization among vertebrates in the wild is rare, it has been recorded in some animal populations. For example, the red wolf of eastern North America is a possible hybrid between the coyote and grey wolf, Live Science previously reported.

Even rarer, however, is when a hybrid species becomes reproductively isolated and forms a stable population that no longer freely mixes with its parent species. This is what the golden-crowned manakin accomplished: It established its own new species with unique characteristics in a remote area of the south-central Amazon Rainforest, the researchers said. This area is separated from the parent species' habitat by wide rivers that act as natural barriers.

"Without geographic isolation, it's very likely this would never have happened because you don't see the hybrids evolving as separate species in other areas where both parental species meet," Weir said. "This is what makes the golden-crowned manakin such a novel animal."

The researchers collected feather samples and performed genetic tests that revealed that about 20 percent of the golden-crowned manakin's genome came from the snowy-crowned manakin and about 80 percent came from the opal-crowned manakin, according to the study.

Using a technique called coalescent modeling, the researchers were also able to determine that the golden-crowned manakin emerged about 180,000 years ago, when the two parental species originally mated. Furthermore, the researchers found that both parental species diverged from a common ancestor about 300,000 years ago.

"Most Amazon bird species diverged from their most recent relative around 1.5 [million] to 4 million years ago, so these are all young birds by comparison," said Weir, who is an expert on the biodiversity of New World birds.

Colorful keratin

While the snow-capped manakin has bright, snowy-white crown feathers, the opal-crowned manakin has brilliant, iridescent crown feathers. Male birds use these highly reflective colors to attract female mates in the dark interior of the rainforest. Hybrid and parent species generally have similar characteristics, but the golden-crowned manakin somehow evolved with a distinctive golden head that doesn’t resemble the crown feathers of either of its parents. [Real or Fake: 8 Bizarre Hybrid Animals]

To better understand why the golden-crowned manakins have such a strikingly different coloring, the researchers examined the keratin structure of the crown feathers of all three of the bird species. Their analysis showed that the two parent species have very different structural arrangements of keratin that create the snowy-white and brilliant iridescent crown feathers.

As a result of hybridization, golden-crowned manakins have a mix of keratin structures from both parental species. It is believed that the members of the species originally had duller white or grey feathers as a result of their keratin structure and then later evolved yellow feathers to increase their visibility in the forest and attract female mates, the researchers said.

Their findings were published Dec. 26 in the journal Proceedings of the National Academy of Sciences.

Original article published on Live Science.

You can explore the Amazon rainforest's spectacular beauty and biodiversity right from the comfort of your home, thanks to a new 360-degree virtual-reality film from Conservation International.

The film, called "Under the Canopy," brings viewers into the depths of the Amazon, with the region's diverse environment on full display. But beyond the picturesque views, the film also shares a message with viewers: This incredible landscape is threatened and needs to be protected. The annual forest loss due to deforestation in the Amazonia region is more than 1.5 times the size of Yellowstone National Park, according to Conservation International, the nonprofit environmental organization that developed the virtual-reality experience.

The film begins at the top of a 200-foot-tall (60 meters) Ceiba tree. After descending to the rainforest floor, viewers set out on a journey with an indigenous guide named Kamanja Panashekung. Panashekung's family has lived in the region for generations, and he shows viewers how the rainforest supplies everything his people need to survive, according to Conservation International. [Beyond Gaming: 10 Other Fascinating Uses for Virtual-Reality Tech]

"Kamanja's community is one of over 350 indigenous communities throughout Amazonia that depend on the rainforest, as we all do, for the air we breathe and the water we drink," M. Sanjayan, Conservation International's executive vice president and senior scientist, said in a statement. "'Under the Canopy' gives those who may never visit the Amazon rainforest an opportunity … understand what is at risk. Sustaining the Amazon is not an option; it is a necessity."

However, the impact of deforestation is not limited to the 30 million people who call the Amazon home. Trees in the Amazon act as a carbon sink — absorbing and storing carbon dioxide, which helps lower greenhouse gas levels in the atmosphere.

The Amazon region also supports more flora and fauna species than any other environment, playing an important role in global biodiversity, scientists have said. Throughout the film, viewers will encounter tropical birds, butterflies, sloths and more.

Using either a virtual-reality headset for an immersive experience or watching the 360-degree video, viewers will see firsthand what the people, plants and animals of Amazonia experience. The film addresses how deforestation and climate change impact their ecosystem, said Chris Holtz, director of conservation and sustainable development at the MacArthur Foundation, which supported the production of the film.

"Intact forests play a unique role in mitigating climate change and regulating the functioning of the planet. Yet, many are at risk," Holtz said in the statement. "The virtual reality experience of 'Under the Canopy' allows anyone to immerse themselves in the rainforests of Amazonia and walk alongside members of an indigenous community in Suriname who conserve these forests as part of their traditional lands and, importantly, for the benefit of all humanity."

Original article on Live Science.

Enormous geometrical earthworks found in the Amazon rainforest were built after humans had already begun altering the forest ecology, but the purpose of these huge ditches remains mysterious, according to new research.

The geoglyphs — trenches as big as 36 feet (11 meters) wide and 13 feet (4 m) deep — were dug at various times between the first and 15th centuries. The geoglyphs were discovered in the 1980s, when deforestation for cattle ranching and other agricultural purposes exposed the earthworks, said Jenny Watling, an archaeologist at the University of São Paulo in Brazil, who led the research while she was a doctoral candidate at the University of Exeter in the United Kingdom. The question, Watling told Live Science, was how the landscape looked when the geoglyphs were built.

"There's been a very big debate circling for decades now about how pristine or man-made the Amazonian forests are," Watling said. The new study suggests that humans have been altering these forests for about 4,000 years. [See Aerial Photos of the Amazon Earthworks]

An altered Amazon

Watling and her colleagues dug soil samples from holes 5 feet (1.5 m) deep at two geoglyph sites, called Jaco Sá and Fazenda Colorada, in the state of Acre in far western Brazil. They analyzed these soils for charcoal, which indicates burning activity, as well as for stable carbon isotopes, molecular variations of carbon that can reveal whether the plants that used to grow there were grassland or forest species. Finally, the researchers examined the samples for phytoliths, microscopic plant remains that can help scientists identify specific ancient species.

The researchers found that the forest has been bamboo-dominated for at least 6,000 years, indicating a certain level of resiliency to climate change and human activity. Whereas the rainforest in nearby Bolivia converted to savanna about 6,000 years ago during a dry period in the climate, the forest in Acre state stayed strong, Watling said.

The analyses showed that charcoal layers appeared about 4,000 years ago, around the same time that archaeological evidence shows that humans moved into the region, the researchers report today (Feb. 6) in the journal Proceedings of the National Academy of Sciences.

The charcoal indicates fires, most likely human-set, that would have been used to clear the forest. After humans started altering the landscape, palm trees became more common in the forest, the analysis showed.

People likely encouraged palms to grow because they provided both food and building material, Watling said. Palms are some of the first trees to come back after the forest is cleared, the researchers wrote, though they're eventually outcompeted by larger, slower-growing trees. Because palms remained plentiful for around 3,000 years, humans were likely altering this cycle, preventing newer trees from overtaking the useful palms. After the geoglyphs were abandoned about 650 years ago, palms became less common again, the researchers said.

Geoglyph mysteries

With human activities beginning about 4,000 years ago, the 2,000-year-old geoglyphs were relative newcomers to the archaeological scene, the researchers found.

"The geoglyphs were actually built within forest that had already been altered," Watling said. "People were already there, changing the composition of the forest."

Maize and squash were grown near the earthworks, Watling found in earlier research, but archaeologists have not seen evidence of villages, or even persistent dwellings, there. However, there are signs that rituals were conducted there, Watling said, namely smashed, decorated pots found near the entrances to some geoglyphs. People might have come to the geoglyph sites sporadically, perhaps during harvest seasons, to gather food from the "prehistoric supermarket," Watling said.

"There's loads of them," she said. "And we don't really know why."

Geoglyphs are found all over the world; famous examples include the Nazca Lines in Peru, dozens of geometric shapes in Kazakhstan and wagon-wheel designs in Jordan.

Original article on Live Science.

Diamond in the Rough

The Brazilian state of Acre is home to more than 450 mysterious earthworks called geoglyphs, most built sometime between 2,000 and 650 years ago. Archaeologists have found that these sites weren't villages and probably weren't fortifications; more likely, they were ritual sites where people gathered temporarily, perhaps during harvest times. New research reveals that humans built these geoglyphs in forests that they had already been altering for hundreds or thousands of years. [Read full story about the mysterious Amazonian geoglyphs]

Earthworks revealed

Acre's geolgyphs were hidden by forest until ranching and other activities led to massive deforestation in the 1980s. An analysis of the ancient vegetation at two sites, Jaco Sá and Fazenda Colorada, found that humans started clearing the forests by burning at least 4,000 years ago. The sites were dominated by bamboo forest for at least 6,000 years, but humans encouraged useful species like palms to grow in cleared areas. The geoglyphs were likely constructed in small temporarily cleared areas, University of Sao Paulo archaeologist Jenny Watling and colleagues reported Feb. 6 in the journal PNAS.

Hidden shapes

Circular geoglyphs are visible from the air in deforested areas of Acre state in western Brazil. Researchers were surprised to find that when the geoglyphs were built around 2,000 years ago, the forest canopy was present, meaning that there had not been widespread deforestation by ancient people. Instead, people seem to have cleared small areas to encourage colonization by useful species like palm trees, which provided food and building material.

Digging ditches

The Brazilian geoglyphs are huge. Many of the ditches are as wide as 36 feet (11 meters) and as deep as 13 feet (4 m). They can be between 330 and 980 feet (100 to 300 meters) in diameter. There are few artifacts found within the geoglyphs, but archaeologists have discovered decorated pots, smashed in place, near some entrances to the earthworks. These discoveries suggest that offerings were made or rituals conducted within and around the geoglyphs, the University of Sao Paulo's Watling told Live Science.

Double Circle

In the new PNAS study, researchers took soil samples from holes 5 feet (1.5 m) deep and analyzed chemical traces of the ancient vegetation that once grew near two geoglyph sites. They found that the sites had been dominated by bamboo forest for 6,000 years at minimum, and that humans began clearing areas of forest with fire 4,000 years ago. Palm trees moved into the cleared areas, and persisted for thousands of years, suggesting that humans were clearing away the slower-growing trees that typically take over from palms in a natural forest progression.

Ancient remnants

Little is known about the people who built these impressive earthen designs. Archaeologists believe that networks of loosely affiliated peoples gathered at these sites sporadically. The new research on forest clearing suggests that the Amazon has been altered by humans for thousands of years and that the forests are not pristine. (Though modern deforestation dwarfs what ancient people did with stone axes and fire.)

Fazenda Atlantica

Geoglyphs at a site known as Fazenda Atlantica in Acre state, western Brazil. Ancient people may have practiced "agroforestry" here, a method of encouraging useful species to colonize cleared areas while removing less-useful plants that compete with those species.
These findings should "serve to highlight the ingenuity of past subsistence regimes that did not lead to forest degradation, and the importance of indigenous knowledge for finding more sustainable land-use alternatives," to modern-day clear-cutting, the University of Sao Paulo's Watling said in a statement.

Dots mark the spot

Archaeologists found that after humans abandoned the geoglyphs around 650 years ago, palm species declined and a more natural forest ecology returned. However, there are still signs of human management echoing in the forests. The forest near the Jaco Sa geoglyph has a higher-than-average proportion of species useful to humans today, Watling and her colleagues found — nine out of its 10 most abundant species are used by people. This may be the ecological remnant of thousands of years of human forest management.

A scientist studying in Peru recently found a strange bulb bursting out of a tree in the Amazon jungle. It turned out that the bulb was actually a parasitic plant that flowers just a few weeks a year, and was the backbone of a tiny ecosystem of creatures that survived on it. [Read the full story on the weird parasitic plant]

Yellow dots

While walking in the Amazon in southeastern Peru, Aaron Pomerantz, an field biologist at the Tambopata Research Center, came across a bizarre site: strange yellow bulbs that seemed to burst from the bark of a tree. (Photo credit: Aaron Pomerantz)

Caterpillar interloper

When he took a closer look, he realized that a caterpillar was actually feeding on the bulb. The caterpillar belonged to the family Lycinadae, which is the second-largest family of butterflies. (Photo credit: Aaron Pomerantz)

Fungus or plant?

Though he initially thought the yellow bulb was a fungus, after consulting a number of botanists around the world he realized the bulbs came from a parasitic plant. The plant, which is part of the family Apodanthaceae, is a cryptic species that spends most of its life lurking hidden inside the tree. The yellow bulbs were actually the flowers of this plant, which emerge just a few weeks a year. (Photo credit: Aaron Pomerantz)

Friends with benefits

The caterpillar wasn't the whole story, however. A second look revealed that an ant fed on nectar secreted by the caterpillar from a special organ on its back called the dorsal nectary organ. This relationship may seem like a raw deal for the caterpillar: after all, producing nectar only for someone else to eat it is costly. However, the ant does bodyguard duty, shielding the defenseless caterpillar from hungry wasps and spiders that might otherwise eat it. The relationship may look like symbiosis, but it's actually a more complicated and fraught form called myrmecophily. (Photo credit: Aaron Pomerantz)

Caterpillar morphology

Here, a closeup of the caterpillar's body. The organ on its back, called the dorsal nectary organ, doesn't release nectar all the time. The ant makes the drumming motion on the caterpillar to release a droplet of nectar. (Photo credit: Aaron Pomerantz)

Small scale interaction

The whole drama takes place on a small scale. Here, Pomerantz shows the size of the caterpillar in comparison to his finger. (Photo credit: Aaron Pomerantz)

Butterfly wings

Interestingly, when Pomerantz returned to film the interaction, he noticed a small gray butterfly landing on the bark of the tree. The butterfly had a strange yellow dot on its wing and blended into its background on the tree. That suggested the butterfly had evolved a camouflage that mimicked the tree bark and its parasite, implying that the trio of creatures had a long-term evolutionary relationship. (Photo credit: Aaron Pomerantz)

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Scientists have found a bizarre food triangle between three different organisms lurking deep in the Peruvian Amazon.

The cast of characters includes a yellow parasitic plant that bursts forth like boils from tree bark, a caterpillar that feeds on that plant, and an ant that drinks the sweet liquid that the caterpillar produces in a special gland near its neck. And at least one of these critters seems to have evolved specific adaptations that allow it to better take advantage of this complex relationship. [See Images of the Strange Amazon Love Triangle]

"It's really a weird relationship, I've never seen anything like it before," said Aaron Pomerantz, an entomologist who works with a rainforest expedition company at the Refugio Amazonas near the Tambopata Research Center in Peru.

Tree boils?

Pomerantz was walking in the jungle when he spied strange, yellow bulbs that looked almost like dot candy bursting from a tree trunk. When he took a closer look, he realized that a caterpillar was feeding on the yellow bulbs.

But it got even weirder. As the caterpillar gorged on the bulb, an ant seemed to be drumming on the caterpillar's back. This drumming motion spurred the caterpillar to secrete a sugary liquid from a specialized organ on its back, called the dorsal nectary organ, which the ant then devoured. 

It turned out that the caterpillar and the ant had an "I scratch your back, you scratch mine" relationship. The ant does bodyguard duty, warding off spiders, wasps or other ants that eat defenseless caterpillars, while the caterpillar provides snacks for the ant, a relationship known as myrmecophily, Pomerantz said.

"It's multiple layers," Pomerantz told Live Science. "You've got a tree, you've got a parasite inside the tree, you've got caterpillars eating the parasites and then ants taking care of the caterpillar."

Mysterious relationship

Pomerantz emailed several botanists to see if any could identify the plant with the odd-looking bulbs, and they were all stumped. Then a few identified the bulbs as a rare parasitic plant in the family Apodanthaceae. These plants burst from a tree's bark only to flower and be pollinated, Pomerantz said. As for the caterpillars, they are the larvae of butterflies from the family Lycaenidae.

As far as he knew, this is the first time anyone has documented this strange and intricate web of interactions before, Pomerantz added. [See a Video About the Weird Symbiotic Relationship]

Interestingly, when Pomerantz went back to film the strange interactions, he noticed a nondescript gray butterfly with a little yellow dot on its wing laying eggs on the tree. With its coloring, it seemed to blend into the background of the tree and its yellow-bulb interloper.

He said he suspects the caterpillar grows into the gray butterfly, and that the butterfly uses its camouflage coloring to hide from lizards and birds. In other words, both the larval stage and the adult stage of this butterfly species have evolved changes to best take advantage of the tree and its parasitic plant.

"This really points to this long-term relationship," Pomerantz said.

That's especially baffling, considering that the parasites emerge from the trees just a few weeks every year to be pollinated, he said.

Follow Tia Ghose on Twitterand Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

A tiny, foldable microscope that can fit in anyone's shirt pocket is revealing stunning images of nature in the jungle.

The microscope, aptly named the Foldscope, uses paper, miniscule round beads of glass, LED lights — and just a few other materials. Even crazier, the origami microscope can be placed on top of a smartphone to transmit the images it captures, so the photos can be stored and saved.

The Foldscope can magnify objects up to 2,000 times — enough to view an individual bacterium such as an E. coli. What's more, it's fairly rugged and versatile: It requires no power and can be stomped on or dropped from a three-story height without breaking, according to the Foldscope website. [See Stunning Images from the Origami Microscope]

So far, the folded-paper device is just being tested by about 10,000 early "beta testers" all around the world, but the researchers are hoping to roll out commercial development soon.

Tiny but mighty

Manu Prakash, a biophysicist at Stanford University, and his colleagues were able to develop the pocket microscope by taking advantage of the fact that a microscope is, in essence, a very simple device.

At heart, optical microscopes use a curved glass surface to focus light beams and magnify objects. To accomplish this task, the origami microscope uses tiny glass balls with different curvatures, which are placed in a tiny glass capillary tube.

The paper body of the origami microscope can be assembled in just 10 minutes and the instructions are visual, meaning that in theory, anyone can assemble it regardless of what language he or she speaks. The materials to make a Foldscope also cost less than a dollar, meaning it could be distributed eventually to kids in the developing world, allowing them to get a closer look at nature.

Childlike rediscovery

One of the earliest users of the technology is Aaron Pomerantz, an entomologist who works with a rainforest expedition company at the Refugio Amazonas near the Tambopata Research Center in Peru.

"Some of the coolest things are from just scooping the soil up with your hands," Pomerantz told Live Science. "If you just stop and look at a tiny soil sample, it's just crawling with stuff that you have no idea what it is."

Pomerantz has taken the pocket-size device into the jungle on his nature walks, and has been amazed at the hidden beauty lurking around him in the Amazon jungle. So far, he has found a species of mite he was able to identify thanks to the microscopic images, and he used the Foldscope to pinpoint the parasite that infected an Amazon spider.

The Foldscope also revealed the larval insect responsible for bizarre, bumpy, bulblike structures on a plant known as leaf galls. Leaf galls form when insects burrow into leaves to lay eggs, which spurs leaves to release their own growth hormones, forming a makeshift home for the larva.

From teensy, alienlike insects crawling in the sand to the gorgeous pebbly texture on a flower petal, the experience has changed how Pomerantz looks at things when he goes exploring, he said.

"You say, 'Oh, I bet I can look at that under a microscope, I bet that will look weird," Pomerantz said.

Additional images from the microscope can be found at the site Microcosmos.

Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

Researchers at Stanford University have developed a tiny, foldable microscope that is made of paper, but can magnify objects up to 2,000 times their original size.The origami microscope, called the Foldscope, has already been sent to 10,000 testers in dozens of countries. So far, it has revealed the hidden life of tiny objects lurking in the Amazon jungle. [Read the full story on the Foldscope microscope]

Mysterious mite

Aaron Pomerantz, an entomologist with the Tambopata Research Center in Peru, took the pocket-sized microscope out when exploring the Amazon jungle. When he encountered a mysterious looking, tiny mite, he was able to send the ultra-closeup images to other researchers and have it identified. (Photo credit: Aaron Pomerantz)

Cheap parts

The Foldscope can be made with parts that cost less than one dollar. The innovative design takes advantage of the fact that all a microscope really needs is a curved glass surface to bend light, so the Foldscope uses tiny glass beads to create the desired magnification. When people want to share their photos of their tiny discoveries, they can place their phone on top of the microscope to transfer the images. (Photo credit: Aaron Pomerantz)

Weird plant growth

One of the strange things Pomerantz encountered were leaf galls, or strange growths that dot some plant leaves. Leaf galls form when insects chew through or burrow through leaves to place their eggs or larvae. This can stimulate the plants to produce a local excess of growth hormone, leading to the strange, bumpy growths. Here, Pomerantz was able to identify the type of larvae responsible for these leaf galls.

Skipper wings

Here, the origami microscope reveals some of the texture on Skipper Butterfly wings. Though Skippers may fly worldwide, they are in abundance in the Amazon Rainforest. Because the Foldscope is pocket-sized and can be assembled in less than 10 minutes even by a child, Pomerantz has gotten in the habit of taking it with him on nature walks.

Hidden beach secrets

When he returned home to the Los Angeles area, Pomerantz also managed to take some photos of the hidden life that lurks near the sea. Here, he captured some of the kelp spotted at the beach closeup, as well as some of the sea creatures, such as a worm, that ride the waves.

Milkweed plant

Here, Pomerantz used the origami microscope to show the strange texture underlying the Milkweed plant.

Rough surface

Even the smoothest of flower petals may look different up close. Here, Pomerantz used the foldscope to reveal the dotted texture of a flower petal.

Insect infection

The origami microscope also revealed the parasite Cordyceps which had infected a spider. Though the black spots are so miniscule that they are barely visible to the naked eye, with the Foldscope, the fine structure of the fungus is revealed.

Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

The Peruvian government plans to make its first contact with the Mashco Piro, an isolated tribe that live in the Amazon rainforest.

Reaching out to "uncontacted" tribes is controversial, particularly because isolated tribes lack immunity to common diseases, which can quickly turn deadly. But officials say they need to contact the Mashco Piro because the group has recently been emerging from the forest, and have had contact with villagers, tourists and missionaries.

In September 2014, for example, the advocacy group Survival International reported that Adventist missionaries had left food and clothes for the tribe near the border of Manu National Park. Gestures like this have spread diseases to uncontacted people in the past, causing epidemics.

Tour companies also advertise "human safaris," promising glimpses of Mashco Piro tribespeople along riverbanks. [See Photos of the Uncontacted Amazon Tribes] 

As a result of these largely unplanned, uncontrolled contacts, some anthropologists argue for deliberate contact with isolated peoples. (Most uncontacted tribes do have limited interactions with their neighbors and are aware of the outside world, but choose to maintain an isolated and nomadic lifestyle in the forest.)

"Unless protection efforts against external threats and accidental encounters are drastically increased, the chances that these tribes will survive are slim," anthropologists Robert Walker of the University of Missouri and Kim Hill of Arizona State University wrote in an editorial in the journal Science in June.

Controlled contact — with medical treatment available for inevitable disease transmission — is safer, Hill and Walker argued.

"A well-designed contact can be quite safe, compared to the disastrous outcomes from accidental contacts," they wrote. "But safe contact requires a qualified team of cultural translators and health care professionals that is committed to staying on site for more than a year."

Organizations such as Survival International strongly oppose contact, arguing instead for strict protections of native land. Given activities such as illegal logging and drug trafficking, however, those protections can be hard to enforce.

The Mashco Piro have been making their own forms of contact, according to Reuters. Members of the tribe attacked a settlement of the Machiguenga tribe in May 2015, killing one man. Another clash in 2011 between locals and the tribe reportedly left one dead and a park ranger injured. Two groups of uncontacted Peruvians approached Brazilian authorities in July and August 2014, saying they had been attacked by non-Indians, possibly drug runners or illegal loggers.

Peruvian policy usually calls for leaving isolated tribes alone, but these incidents have led to an exception. The goal of the planned contact is to find out why the Mashco Piro have been emerging from the forest more frequently, in hopes of preventing more clashes.

"In 2014, there were 70 sightings of Mashco Piro on the beaches of the river," Patricia Balbuena, the deputy minister of multiculturalism in Peru, told the newspaper El Comercio. In 2015, she said, there have already been five raids on local communities by the group.

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

The Amazon rainforest, often thought to have been pristine wilderness before the modern era, was once domesticated, and was reclaimed by the wild only in recent centuries, research increasingly suggests.

The Amazon, the world's largest river basin, is home to the largest rainforest on Earth, covering about 2.6 million square miles (6.7 million square kilometers) across nine countries. This area, known as Amazonia, holds an extraordinary array of life, harboring one in 10 known species in the world and one in five of Earth's birds.

Although the Amazon is often thought of as pristine nature, over the past few decades, archaeologists have discovered evidence of numerous large, complex societies that may have inhabited Amazonia in the past. While these findings contrast with the small Amazonian societies anthropologists investigated in the 20th century, they are in line with initial eyewitness accounts of Europeans from the 16th and 17th centuries. [Images: One-of-a-Kind Places on Earth]

To investigate what Amazonia was like before the European conquest, lead study author Charles Clement, a crop geneticist and historical ecologist at Brazil's National Institute of Amazonian Research in Manaus, and his colleagues collected data on the plants, soil and landscape of Amazonia, as well as projections of population sizes and maps of where Amazonian languages are spoken.

"It is consensus that central and southern Amazonia were well populated, with abundant domesticated plants, forests, landscapes and soils," Clement told Live Science.

At least 83 native Amazonian species were domesticated to some degree by the time of contact with Europeans, including sweet potato, cacao, tobacco, pineapple, cassava and hot peppers, as well as numerous fruit trees and palms. Another 3,000 to 5,000 plant species that were not domesticated were nevertheless used in some way, the researchers said. Although many present-day Amazonian forests may seem natural, research suggests they are domesticated to varying degrees, possessing different populations of plants than one would expect in a naturally biologically diverse forest.

Prior research also had discovered Amazonian dark earths — soils that are rich in nutrients and carbon resulting from human waste and fires, mulching and composting on farms. Sites rich in Amazonian dark earths may cover more than 0.1 percent of Amazonia, first appearing in parts of the Amazon 6,000 years ago and increasingly rapidly in number and size about 2,500 years ago, the researchers said.

All together, farming on sites rich in Amazonian dark earths may have supported at least 8 million people in 1492, the researchers said. "When most people think about the grandeur of past Native American societies, they think of the Aztec, Maya and Inca pyramids," Clement said. "Native Amazonians did not have pyramids, perhaps because there was no stone. What most impressed the first Spanish adventurers were the large numbers of healthy, well-fed people, and the abundance of food in every community they visited in Amazonia. This convinced them that the soils were rich and that the native peoples knew how to manage them for food production."

Amazonia reverted to wilderness after Columbus arrived in the New World, Clement said. "The Colombian Encounter, as it is often called, resulted in the introduction of European, African and Asian diseases to which Native Americans had no immunity," he added.

For instance, smallpox, which is thought to have arrived in the Americas via a Spanish ship that landed in Mexico, devastated the Inca Empire, paving the way for its conquest by a handful of Spaniards, Clement said. "Within a century after the beginning of conquest, disease had wiped out 50 percent of the Native American populations," he said.

Although Amazonia reverted to wilderness after the decimation of its native peoples, Clement stressed that it doesn't mean the Amazon rainforest will return wherever modern society allows it to. "This is a fallacy because Native Amazonians did not clear-cut the forest, nor plant pastures and soy," Clement said. "We are not saying that modern society can clear-cut the forest for food production."

Future research can investigate "how the Native Amazonians could support complex societies without destroying the environment," Clement said. "We might learn something from Native Amazonians."

The scientists detail their findings online July 22 in the journal Proceedings of the Royal Society B.

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Harpy eagles nesting high above the understory of the Peruvian rainforest have been captured in a series of stunning new photos.

One of the eagles is a mama bird, while the other is an adorable eagle chick.

Because the giant bird of prey lives in the darkest portions of the rainforest and hunts its quarry in dead silence, many Peruvian Amazon birders can go their entire lives without seeing one, said nature photographer Jeff Cremer, who photographed the eagles. [See Gorgeous Images of the Adorable Harpy Eagle Chick]

"It's about as rare as seeing a unicorn," Cremer told Live Science.

Rare creatures

Harpy eagles (Harpia harpyja) are imposing creatures. The massive birds can be up to 3 feet (0.9 meters) tall, with wingspans reaching 6 feet (1.8 m), Cremer said. Like stealth bombers, the birds of prey glide silently; they move through the shadows of the rainforest, hunting sloths, monkeys and even an occasional deer, Cremer said. To better hunt their prey, the eagles can turn their heads 180 degrees to face upward while flying through the dense rainforest, and can also fluff up their white head feathers, creating an acoustic funnel to direct sound to their ears.

When they do capture an unsuspecting animal, the eagles crush it, killing it instantly with their huge talons, which can produce hundreds of pounds of force, Cremer added.

"They have claws the size of an adult grizzly bear," Cremer told Live Science.

But the eagles are tough to spot, because they build their nests in the dark region between the forest's understory and canopy, high up in the trees, where the limbs just begin to branch out. In addition, logging and illegal mining have sharply reduced the harpy eagle's natural habitat and the majestic hunter is now considered near threatened by the International Union for the Conservation of Nature. As a result, seeing a harpy eagle chick in the wild in this region is incredibly rare, Cremer said.

Baby bird

Guides at the Tambopata Research Center in Peru first became aware of the birds of prey after noticing a nest high up in the trees. The guides also saw a harpy eagle fly over their heads, carrying the head of a half-eaten sloth to the nest, which contained a single chick. After monitoring the nest, Cremer and his colleagues decided to climb up to take photos.

Getting those pictures was no easy feat. The nest was perched high in the branches of an ironwood tree, about 100 feet (30 m) above the ground, so the team had to toss a slingshotlike rope up to the branches and then ascend using special climbing gear. 

Harpy eagles create just two eggs each laying season, but only one hatches; the other is a backup in case the first fails to hatch, Cremer said. Harpy eagle chicks typically stay in the nest for about a year. As that year goes on, the mama bird will come back to the nest with food less and less frequently, and the chick will gradually have to spread its wings and fly to find its own prey, Cremer said.

Follow Tia Ghose on Twitter and Google+. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.

A photographer recently captured stunning photographs of a rare harpy eagle and her chick in the rainforest of Peru. The expert hunter is an elusive animal to spot, because it flies silently in the darker regions of the Amazon rainforest. (Read the full story on the harpy eagle and her chick)

Bird of prey

The harpy eagle, (Harpia harpyja), lives in the Amazon rainforest. The elusive creatures can be up to 3 feet tall and have a 6-foot wingspan. (Photo Credit: Jeff Cremer photography/Perunature.com)

Watching and waiting

The eagle typically lives between the understory and the canopy of the jngle, in the darkest reaches of the forest.  Illegal mining and logging has dramatically reduced its habitat, and the elusive creatures are now considered near threatened by the International Union for the Conservation of Nature. (Photo Credit: Jeff Cremer photography/Perunature.com)

Silent hunter

The stealthy predator flies silently through the forest, looking for animals to eat. Here, a harpy eagle with the body of one its prey. The eagle kills its prey by crushing it in massive talons, which can produce hundreds of pounds of force. (Photo Credit: Jeff Cremer photography/Perunature.com)

Rare sighting

Harpy eagles live in shadows of the rainforest, and as such, can be hard to spot. Some Amazon birders can go their whole lives without seeing one. (Photo Credit: Jeff Cremer photography/Perunature.com)

Baby chick

Conservationists at the Tambopata Research Center noticed the nest of a harpy eagle high in an ironwood tree. Jeff Cremer, a nature photographer working at the center, climbed up the tree and managed to take photos of the adorable baby chick, along with its mama. (Photo Credit: Jeff Cremer photography/Perunature.com)

Adorable but deadly

The cute little bird will spend its first year of life in the nest, but even before it leaves for good, the baby is already learning the skills needed to hunt and kill. (Photo Credit: Jeff Cremer photography/Perunature.com)

Eagle updo

Though the fluffy head feathers on this harpy eagle chick may look funny, they actually serve a purpose: The upswept feathers create a kind of acoustic funnel, directing sound toward the chick's ears and providing it with a keen sense of hearing for finding prey. (Photo Credit: Jeff Cremer photography/Perunature.com)

Here, a photo of the mama bird with its chick. The harpy eagle typically lays two eggs each year, but only one hatches. The mama will spend the next year making sure the bird grows, bringing back food. As the chick grows, she will return with prey less and less often. (Photo Credit: Jeff Cremer photography/Perunature.com)

The vast jungles of the Amazon rainforest harbor tribes mostly isolated from the outside world, whose way of life, largely unchanged for millennia, is now increasingly threatened by intrusions from modern civilization.

Now, scientists reveal they can monitor these "uncontacted tribes" using satellites, which would allow safe, inexpensive and noninvasive tracking of these tribes in order to protect them from outside threats.

The Amazon is the largest and most diverse rainforest in the world— about 10 percent of all known species on Earth dwell there. The long-term survival of the estimated 50 to 100 isolated tribeswho live in the region is under increasing threat of disease and violence as the tribes encounter the rest of the world. [Gallery: Images of Uncontacted Tribes]

In order to help conserve these uncontacted Indians, researchers need accurate estimates of their populations. One way to collect this data involves flying over their villages, but such overflights are both expensive and invasive, and could instill fear among these indigenous peoples. Another strategy involves encountering individuals on the ground, but among other risks, scientists could accidentally spread disease to members of the tribes.

Instead, scientists investigated whether satellite imaging could monitor uncontacted tribes. "Since college some 15 years ago, I've always been fascinated by these isolated tribes," said lead study author Robert Walker, an anthropologist at the University of Missouri at Columbia. "I've always wanted to study them in a safe way, and remote sensing offers that."

The investigators focused on indigenous groups concentrated near the headwaters of the Envira River, located at the border of Brazil and Peru. These include the Mashco-Piro, nomadic hunter-gatherers who live in Peru's densely forested Madre de Dios region, and a number of Pano-speaking farming societies.

The researchers combed through satellite images to look at five isolated villages previously identified via overflights by Brazilian officials. They confirmed these locations and measured the sizes of their villages, houses and gardens. The villages ranged from a small one of about 50 people to a large and growing village of about 300 people.

"We can find isolated villages with remote sensing and study them over time," Walker told Live Science. "We can ask: Are they growing? Do they move?"

Surprisingly, based on the sizes of the houses and villages, the scientists find the population densities of these isolated villages is about 10 times greater, on average, than other villages of indigenous Brazilian peoples. This may be due to the fact that they have to live closer together because they are not as good at clearing the forest, since they lack steel machetes and axes as well as modern devices like chainsaws and tractors, the researchers said. The tribes may also be afraid of spreading out due to fear of being attacked by outsiders, Walker said.

The researchers now plan to focus on 29 more isolated villages to "look at their ecology — that is, elevation, distance from rivers and roads — and use this to model where else we can find more isolated villages," Walker said.

The scientists detailed their findings online today (Nov. 5) in the journal Royal Society Open Science.

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A series of square, straight and ringlike ditches scattered throughout the Bolivian and Brazilian Amazon were there before the rainforest existed, a new study finds.

These human-made structures remain a mystery: They may have been used for defense, drainage, or perhaps ceremonial or religious reasons. But the new research addresses another burning question: whether and how much prehistoric people altered the landscape in the Amazon before the arrival of Europeans.

"People have been affecting the global climate system through land use for not just the past 200 to 300 years, but for thousands of years," said study author John Francis Carson, a postdoctoral researcher at the University of Reading in the United Kingdom. [See Images of the Ancient Amazonian Earthworks]

Blemished Amazon?

For many years, archaeologists thought that the indigenous people who lived in the Amazon before Christopher Columbus arrived in the Americas in 1492 moved across the area while making barely a dent in the landscape. Since the 1980s, however, deforestation has revealed massive earthworks in the form of ditches up to 16 feet (5 meters) deep, and often just as wide.

These discoveries have caused a controversy between those who believe Amazonians were still mostly gentle on the landscape, altering very little of the rainforest, and those who believe these pre-Columbian people conducted major slash-and-burn operations, which were later swallowed by the forest after the European invasion caused the population to collapse.

Carson and his colleagues wanted to explore the question of whether early Amazonians had a major impact on the forest. They focused on the Amazon of northeastern Bolivia, where they had sediment cores from two lakes nearby major earthworks sites. These sediment cores hold ancient pollen grains and charcoal from long-ago fires, and can hint at the climate and ecosystem that existed when the sediment was laid down as far back as 6,000 years ago.

Ancient landscape

An examination of the two cores — one from the large lake, Laguna Oricore, and one from the smaller lake, Laguna Granja — revealed a surprise: The very oldest sediments didn't come from a rainforest ecosystem at all. In fact, the Bolivian Amazon before about 2,000 to 3,000 years ago looked more like the savannas of Africa than today's jungle environment.

The question had been whether the early Amazon was highly deforested or barely touched, Carson said.

"The surprising thing we found was that it was neither," he told Live Science. "It was this third scenario where, when people first arrived on the landscape, the climate was drier."

The pollen in this time period came mostly from grasses and a few drought-resistant species of trees. After about 2,000 years ago, more and more tree pollen appears in the samples, including fewer drought-resistant species and more evergreens, the researchers report today (July 7) in the journal Proceedings of the National Academy of Sciences. Charcoal levels also went down, indicating a less-fire-prone landscape. These changes were largely driven by an increase in precipitation, Carson said.

The earthworks predate this shift, which reveals that the diggers of these ditches created them before the forest moved in around them. They continued to live in the area as it became forested, probably keeping clear regions around their structures, Carson said.

"It kind of makes sense," he said. "It's easier to stomp on a sapling than it is to cut down a big Amazonian tree with a stone ax." [Gallery: Biodiversity of the Amazon (Photos)]

Questions answered

The discovery that the human activity came before the forest answers some questions, like how Amazonian people could have built in the rainforest with no more than stone tools (they didn't have to), how many people would have been necessary to construct the structures (fewer than if clear-cutting had been required), and how the population survived (by growing maize).

The study also has wider implications for the modern day, Carson said. The question of how to preserve the Amazonian rainforest is difficult to answer; some people say humans need to get out, and others believe people and the forest can coexist. Ancient history could provide a guide, as well as a greater understanding of how the forest has recovered from earlier perturbations. (The Amazon also drives climate as well as responds to it, thanks to its ability to take up carbon from the atmosphere.)

The new study suggests that the modern forest is a coproduction between humans and nature, Carson said. Natural cycles drove the rainforest to sprout, but humans stayed on-site for 1,500 years afterward, he said.

"It's very likely, in fact, that people had some kind of effect on the composition of the forest," Carson said. "People might favor edible species, growing in orchards and things like that, [or] altered the soils, changing the soil chemistry and composition, which can have a longer-lasting legacy effect."

Those long-range changes are next for Carson and his colleagues to investigate. "This kind of study has only just started in Amazonia," Carson said.

Follow Stephanie Pappas on Twitter and Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Ring ditches

Researchers have found that earthworks, consisting of an array of square, straight and ringlike ditches that dot the Bolivian and Brazilian Amazon existed before the rainforest sprouted up. Shown here, a ring ditch next to Laguna Granja in the Amazon of northeastern Bolivia. [Read full story]

Man-made structures

Scientists aren't sure the purpose of these man-made earthen structures of the Amazon, with ideas ranging from their use in defense, drainage or even ceremonial/religious purposes. Here, one of the ringlike ditches in the Amazon of Boliva. [Read full story]

Mysterious structures

But how were these structures created? For some time, archaeologists had thought prehistoric people barely touched the Amazon landscape before Christopher Columbus arrived in the Americas in 1492. Then in the 1980s, deforestation revealed these massive earthworks spanning some 16 feet (5 meters) wide and often just as deep. Here, one such ringlike ditch in the Bolivian Amazon. [Read full story]

Altering a landscape

The existence of these structures (shown here) suggested the people perhaps did "touch" the landscape more deeply. New research, detailed July 7, 2014, in the journal Proceedings of the National Academy of Sciences, aimed to figure how prehistoric people altered the landscape here before the Europeans arrived. [Read full story]

Amazon fieldwork

Here the researchers and field guides prepare their boat to one of the lake sites, where they examined sediment cores for ancient pollen grains.

Amazon boating

To figure our if the Amazonians had a major impact on the forests, researchers, including John Francis Carson (shown here) examined sediment cores from two lakes in the Amazon of northeastern Bolivia. Shown here, the larger of the two lakes called Laguna Oricore. (They also looked at sediment from the smaller lake, Laguna Granja. [Read full story]

Looking for pollen grains

Carson and his colleagues (with field guides who are pictured here) took sediment cores from the two Bolivian lakes, looking for ancient pollen grains and charcoal that might reveal the climate that existed as far back as 6,000 years ago.

Amazon campsite

Here the researchers (F. Mayle, J. Carson and J.D. Soto), as well as Bolivian field guides/rangers sit at their campsite in the Bolivian Amazon.

SACRAMENTO, Calif. — Peru's Amazon rainforest is extensively contaminated from decades of oil and gas drilling, researchers reported yesterday (June 12) here at the annual Goldschmidt geochemistry conference.

In the past decade, volatile demonstrations by indigenous groups and tangled lawsuits against oil companies have exposed the toxic legacy of decades of oil drilling in the Western Amazon. People living in the rainforest say they are suffering health effects from the nearby polluted drilling and waste sites, and from eating plants and wildlife laced with heavy metals and petroleum compounds.

But lax government regulations during the early years of oil exploration, combined with a lack of environmental monitoring, mean there's little data on the true extent of contamination in the richly diverse rainforest.

"I was surprised by how little has been published," said study co-author Antoni Rosell-Melé, an environmental chemist at the Autonomous University of Barcelona in Spain.

Now, using publicly available water sampling data, Rosell-Melé and his colleagues have built a comprehensive database of contamination levels during the past 30 years in Peru's remote rainforest. The team plans to publish the database so other scientists can use the data to better understand how oil exploration affects the Amazon rainforest. [See Stunning Photos of the Amazon Rainforest]

"We know a lot about the impacts of deforestation, but very little has been published about the impacts of oil exploration," Rosell-Melé said.

The results confirm the complaints from indigenous and green groups: Pollutant levels exceed government and international standards, the researchers said.

"When we extract oil, it has a very high price for the environment, and sometimes, it's not paid by those who use the oil," Rosell-Melé said.

The data comes from Peruvian public agencies, oil companies and non-governmental organizations, but has never been collected in one place. The database contains 4,480 samples from 10 major rivers, taken between 1983 and 2013.

Nearly 70 percent of the river water samples exceed Peru's limits for lead, and 20 percent exceed cadmium limits, Rosell-Melé said. "There's clearly been impacts from discharge into the rivers," he said.

During the early decades of oil mining, companies dumped their drilling waste into open pits or directly into rivers and streams. Leaky pipelines and wells, as well as accidental oil spills could also produce the contamination detected in the water samples. The heavy metals and other compounds tested were at higher levels downstream of the discharge sites, as compared with levels upstream, which suggests the oil discharges had caused the contamination, the researchers said.

Health effects

High levels of lead and cadmium have been found in blood taken from indigenous people living in the rainforest, and from the wildlife these groups hunt for food, according to earlier studies.

Activists believe the contamination results from such pollutants moving up the food chain, from wildlife to indigenous peoples who rely on the rainforest ecosystem for a subsistence lifestyle.

To confirm that rainforest animals eat in oil-contaminated areas, the researchers set up camera traps in the forest. The traps caught animals such as tapirs feeding directly on the chemicals from the spills, and researchers documented oil in the animals' feces. Rosell-Melé thinks the animals are attracted to the taste of salty wastewater and chemicals. Soils in the rainforest are low in salt, and animals may mistake the spills for natural salt licks, Rossell-Mele said.

According to the database, pollution levels in Peru's rainforest rivers started to drop after 2007, when the government ordered drilling companies to stop dumping toxic waste into rivers.

"The situation has improved over what it used to be, but it's not acceptable by Western standards," Rosell-Melé said.

The new environmental regulations haven't completely prevented new toxic waste spills, however. Peru's Environment Ministry declared an environmental emergency in the Corrientes and Pastaza River basins in March 2013 due to drilling contamination. [Photos: The 10 Most Pristine Places on Earth]

About 30 percent of the world's rainforests overlie fossil fuel reservoirs, Rosell-Melé said. Huge oil and gas reserves have been discovered under the Amazon rainforest in Bolivia, Colombia, Ecuador, Peru and western Brazil. Oil drilling in the Western Amazon peaked in the 1970s, with exploration funded by both private companies and national governments. The rise in oil prices during the 2000s sparked a new drilling boom in the area. More than 180 areas zoned for new exploration and development now cover a section of Amazon rainforest the size of Germany.

"The exploitation of these resources is a threat to biological and cultural diversity," Rosell-Melé said.

EmailBecky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.

The Amazon Rainforest

On May 21, 2014, the Brazilian government, World Wildlife Fund (WWF) and partners announced the creation of a $215 million fund to ensure long-term protection of the world's largest network of protected areas — 150 million acres of the Brazilian Amazon rainforest .

In the last ten years, this partnership effort has already resulted in almost 100 protected areas encompassing 128 million acres — a mix of tourist sites, biological research areas and sustainable use areas where local people can harvest natural resources. The challenge over the years, however, has always been long-term financing to properly manage these areas. The $215 million will be used as a transition fund to be paid out to Brazil over 25 years. During that time, Brazil will gradually increase its own contributions with the intention of establishing permanent financing.

Not only does a network of protected areas that size have immense conservation implications (carbon, freshwater, biodiversity, etc), it also presents a new model for large-scale conservation that can be applied in other countries.

Aerial View of Peru

By 2020, 150 million acres will be protected in the Brazilian Amazon. This is the equivalent of one and a half Californias or the size of Spain.

Blue and Yellow Macaw

The Amazon is home to more than 1,000 species of birds, including the vibrant and iconic blue-and-yellow macaw.

Cutting a Tree in The Amazon

This protected area network is slowing the spread of deforestation—down 75 percent from 2000 to 2012.

The Amazon RIver

The Amazon and its tributaries contain almost 20% of the river water on earth.

Amazon Jaguar

Jaguars need stretches of river bank and large areas of tropical rain forest and grasslands—like those protected under this program—to survive.

Woman Selling Rubber Shoes

This program supports community projects—like these sustainably-sourced rubber shoes for sale—for people in the region.

Kayapo Boy in Brazil

The Brazilian Amazon is home to 20 million people, many whose livelihoods depend on the region’s forests and other natural resources.

Pink River Dolphin

One in 10 of all known species lives in the Amazon. The pink river dolphin lives in the waters of more than half of the protected areas under this program.

Harvesting Nuts From The Amazon

Nearly half of these protected areas are set aside for sustainable uses that benefit local communities (e.g., harvesting rubber and nuts).

Palms in Brazil

This network of protected areas and funding mechanism can serve as a model for other countries seeking innovative means for creating and funding protected areas.

Pristine Amazon forests pull in more carbon dioxide than they put back into the atmosphere, according to a new study. The findings confirm that natural Amazon forests help reduce global warming by lowering the planet's greenhouse gas levels, the researchers said.

When scientists account for the world's carbon dioxide, their totals suggest some of the greenhouse gas disappears into land-based carbon traps. These natural carbon "sinks," such as forests, absorb and store carbon dioxide, helping to lower the greenhouse gas levels in the atmosphere. (Living trees take in carbon dioxide, which they need to grow. Dead trees release their stored carbon back into the atmosphere, through decay.)

But the model of a rainforest as carbon sink is based on small, heavily-studied tree areas called test plots, which means the concept could lose its accuracy when scaled up to the size of a continent. For example, in the Amazon forest, huge swaths of trees can die at once, which can't be accounted for by test plots. In 2005, a single storm killed half a billion trees in the Amazon forest. [Amazon Photos: Trees That Dominate the Rainforest]

To better measure the carbon on the rainforest's breath, researchers tracked tree death throughout the Amazon. Lead study author Fernando Espírito-Santo, a research scientist at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., combined satellite data, airborne lidar (laser surface imagery) and tree counts to compare carbon consumed by living trees with emissions from dead trees.

Espírito-Santo found that dead Amazonian trees emit an estimated 1.9 billion tons (1.7 billion metric tons) of carbon to the atmosphere each year. In a normal year, the Amazon rainforest absorbs about 2.2 billion tons (2 billion metric tons) of carbon dioxide, studies suggest. And the big storms that blow down millions of trees at once barely budge the forest's carbon output, the study found.

"We found that large natural disturbances — the sort not captured by plots — have only a tiny effect on carbon cycling throughout the Amazon," study co-author Sassan Saatchi of JPL said in a statement.

The study did not account for tree deaths from logging or deforestation, the researchers said.

The Amazon River basin is home to the largest rainforest on Earth, covering about 2.67 million square miles (6.9 million square kilometers) in seven countries. Each year, about 2 percent of the entire Amazon forest dies of natural causes. The researchers found that only about 0.1 percent of those deaths are caused by blowdowns.

The findings were published March 16 in the journal Nature Communications.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.

How long does it take to build a little more than 30,000 miles (50,000 kilometers) of new roads through the rain forest? A new study finds that, in the Brazilian Amazon, such development can happen in just three years.

While roads cover only a tiny fraction of the total land surface of South America's largest nation, their effect on local ecosystems — particularly rain forests — may be huge. In an attempt to better understand road-building's effect on the Amazon, researchers from Imperial College London used road maps and satellite images to track the recent development of the Amazon road network.

The team's report, which was published this month in the journal Regional Environmental Change, concluded that approximately 10,000 miles (17,000 km) of roads were built every year in Brazil between 2004 and 2007. Not surprisingly, road networks were found to spread the most quickly in newly settled areas, as well as in areas experiencing renewed economic growth.

This rampant road-building may be a major contributor to deforestation and habitat loss in one of planet Earth's most biologically diverse regions. But by mapping road construction, researchers think they can aid future efforts to stop destruction of the Brazilian rain forest.

"Knowing where the roads are and the speed at which they are built is key to predicting deforestation," Rob Ewers, Imperial College London scientist and co-author of the study, said in a statement. "An understanding of road networks is the big missing gap in our ability to predict the future of this region."

The effects that roads have on local ecosystems extend far beyond the locations of the roads themselves. This includes changes in the temperature and humidity of air and soil and the movement of animals.

Past research suggests that certain configurations of road networks in the Amazon are more sustainable than others. A 2011 study, funded by the National Science Foundation, found that a "fishbone" configuration, for example, offers a solution that merges development with forest livelihood. Such a network allows roads to be built far enough away from one another that animals and connected ecosystems can continue to thrive despite the intrusion of human infrastructure.

But road construction is just one of many factors leading to the continued deforestation of the world's largest rain forest. Forest fires alone destroyed more than 33,000 square miles (85,500 square km) of forest between 1999 and 2010, according to a recent NASA release. That's an area larger than the state of South Carolina.

And a recent report from the Intergovernmental Panel on Climate Change found that forest fires in the Amazon are only going to get worse, as the region's annual dry season — also known as fire season — continues to extend every year.

Logging and farming also contribute to the continued destruction of the Amazon, with one expert attributing up to 90 percent of all cleared land in the region to the expansion of Brazil's cattle ranching industry.

Follow Elizabeth Palermo on Twitter @techEpalermo, Facebook or Google+. Follow us @livescience, Facebook & Google+. Original article on LiveScience.

Bacteria living in the Amazon River can digest woody materials shed by the surrounding rain forest by turning these pieces of tree bark and stems into carbon dioxide as they are washed down the river, according to a new study. The findings bolster the Amazon basin's reputation as being the lungs of the planet, taking in carbon dioxide and releasing oxygen, but show that the carbon dioxide doesn’t necessarily stay trapped in the trees.

Researchers at the University of Washington found that bacteria in the Amazon River can break down almost all of the tree and plant materials in the water, and this process is a major generator of the carbon dioxide breathed by the river.

"Rivers were once thought of as passive pipes," study co-author Jeffrey Richey, a professor of oceanography at the University of Washington in Seattle, said in a statement. "This shows they're more like metabolic hot spots." [The World's Longest Rivers]

To thrive, plants convert sunlight, carbon dioxide and water into food, in a process known as photosynthesis. As they grow, bits of wood and leaves are shed that eventually decompose on the ground, or get washed into the river during periods of rainfall.

Food for the river

Previously, it was believed that much of this plant matter floated down the Amazon River to the ocean, where it ultimately became buried in the seafloor. A decade ago, scientists at the University of Washington discovered that rivers exhale vast amounts of carbon dioxide into the atmosphere, but it was still not known if — or how — river bacteria could break down such tough materials, the researchers said.

"People thought this was one of the components that just got dumped into the ocean," Nick Ward, a doctoral student in oceanography at the University of Washington, and lead author of the new study, said in a statement. "We've found that terrestrial carbon is respired and basically turned into carbon dioxide as it travels down the river."

A compound called lignin forms the main part of a tree's woody tissue, and is the second most common component of terrestrial plants, the researchers said. But rather than flowing into oceans and settling on the seafloor for centuries or millennia, bacteria in the Amazon River can break lignin down within two weeks, the new study found.

In fact, only 5 percent of the Amazon rain forest's plant-based carbon ends up reaching the ocean, the researchers said.

The carbon cycle

While these findings have important implications for global carbon models, they also shed light on the ecology of the Amazon, as well as other river ecosystems.

"The fact that lignin is proving to be this metabolically active is a big surprise," Richey said. "It's a mechanism for the rivers' role in the global carbon cycle — it's the food for the river breath."

From their analysis, the researchers determined that about 40 percent of the Amazon's lignin breaks down in soils, 55 percent is digested by bacteria in the river system, and 5 percent is washed into the ocean, where it breaks down or sinks to the ocean floor.

"People had just assumed, 'Well, it's not energetically feasible for an organism to break lignin apart, so why would they?'" Ward said. "We're thinking that as rain falls over the land it's taking with it these lignin compounds, but it's also taking with it the bacterial community that's really good at eating the lignin."

The study's findings were published online May 19 in the journal Nature Geoscience.

Follow Denise Chow on Twitter @denisechow. Follow LiveScience @livescience, Facebook & Google+. Original article on LiveScience.com.

A battle is looming between one of South America's largest state-backed oil companies and an indigenous community of about 400 in the Ecuadorian rainforest.

The area is near Yasuni National Park, in eastern Ecuador, home to some of the richest variety of life on Earth. Studies have shown that a single hectare here contains a wider variety of life than in all of North America. 

The state-backed company, Petroamazonas, has told the Kichwa tribe that they plan to begin prospecting for oil tomorrow (Jan. 15) in the area, the Guardian reported. But the tribesmen say they are ready to die fighting to protect their land, which covers some 270 square miles (700 square kilometers) of pristine rainforest, an area about four times the size of the District of Columbia. 

The community secretary, Klider Gualinga, told the Guardian that more than 80 percent of the village opposes the oil deal, but that a small minority is pushing it through against their wishes and local rules.

"People think it is dishonest and the oil company is treating them like dogs. It does not respect the land or the planet. There is no deal, nothing is agreed. The people do not want the oil company," Gualinga said. "We have decided to fight to the end. Each landholder will defend their territory. We will help each other and stand shoulder to shoulder to prevent anyone from passing."

The community decided to reject an offer from the company late last year because they were concerned about the long-term environmental impact of mining, the Guardian reported. But the village recently learned that their chief signed a deal to allow the mining, despite not being granted approval. 

Earlier offers of a brand-new school, guaranteed college education of children and improved healthcare were dropped in the document, which promises only $40 per hectare, the Guardian reported.

The villagers stand no chance against Petroamazonas, which is backed by the Ecuadorian military, according to news reports.

Members of the community have started a last-ditch legal effort stop the company, and are being helped by a British businesswoman who is married to the village shaman and who was recently made the head of a local eco lodge (a facility for tourists interested in ecologically-friendly travel), the Guardian noted.

Yasuni National Park, near the tribe's land, is also home to two of the world's last uncontacted tribes. Other tribes without exposure to the outside world likely exist elsewhere in the Amazon, researchers believe.

Reach Douglas Main at dmain@techmedianetwork.com. Follow him on Twitter @Douglas_Main. Follow OurAmazingPlanet on Twitter @OAPlanet. We're also on Facebook and Google+.

Giving Thanks

This Thursday, Americans celebrate Thanksgiving, reflecting on the things in our lives we're thankful for.

In the spirit of Thanksgiving, OurAmazingPlanet is taking a look at some of the places on Earth that nature has given humanity and the benefits they bring, outside of their beauty that we are most thankful for.

Great Barrier Reef

The Great Barrier Reef is the largest living structure in the world and the only one that can be seen from space.

While its beauty is familiar to many, it also hosts an astounding array of species and an incredible amount of biodiversity coral reefs like it are often called the "rainforests of the ocean." The U.S. National Oceanic and Atmospheric Administration notes that coral reefs support the most species per unit area of any of the planet's ecosystems.

The Great Barrier Reef is home to, as a small selection, 400 types of coral, 1,500 species of fish and 4,000 types of mollusk spread among 2,500 coral reefs of various sizes and 900 islands, according to UNESCO, which listed it as a World Heritage Site in 1981.

The richness of species makes the reef important both to scientists studying its species and to humanity in general, as biodiversity is critical to maintaining healthy ecosystems. Such ecosystems also confer economic benefit to humans by filtering air and water, for example, or providing healthy fish stock, according to The Economics of Ecosystems and Biodiversity project (hosted by the United Nations Environment Program).

Galapagos Islands

This tiny archipelago that sits some 600 miles (1,000 kilometers) from the coast of South America in the Pacific Ocean is home to an astounding array of rare and unusual species, many of which are found nowhere else in the world.

The islands' separation from the South American mainland over the eons meant the species of the Galapagos evolved in isolation, adapting to their environment, even from island to island. When Charles Darwin visited the Galapagos in 1835, he noted the specialization of the 13 endemic species of finches found there. The finches looked similar except for their unique beaks; species on different islands evolved differently shaped and sized beaks to take advantage of different food sources.

Darwin closely observed these birds, and it was his notes of their adaptations to their environments, which happened over successive generations, that helped the theory of natural selection coalesce in his mind a theory that underpins much of modern biology to this day.

Coastal Wetlands

They aren't the most glamorous of Earth's ecosystems, but they are incredibly important and are found in coastal areas around the world.

Wetlands help to filter pollutants out of the waters that flow through them, giving humans and other animals access to clean water. Wetlands also provide habitat to many species, including some that are important to the seafood industry.

Wetlands also maintain coastlines and absorb the impacts of hurricanes and other storms, serving as something of speed bumps for storm surges. The loss of coastal wetlands in the New York City area contributed to the devastation wrought by Hurricane Sandy in 2012.

But wetlands are increasingly vulnerable to sea-level rise, human development and the rerouting and damming of tributary rivers.

Boreal Forest

The boreal forests of the Far North are the largest terrestrial ecosystem on Earth, according to the National Resources Defense Council, forming a ring of evergreen trees around the Arctic.

This forest, found across the northern reaches of North America, Asia and Europe, represents a third of all the woodlands left on Earth. The extent of the forest makes it a significant carbon sink, storing 30 percent of all the terrestrially stored carbon on the planet.

The Amazon

The iconic Amazon rainforest confers a number of benefits on humanity. Like the Galapagos and the Great Barrier Reef, the Amazon supports an astounding array of species and has an incredible degree of biodiversity. The rainforest is home to one in 10 known terrestrial species, many of which are found nowhere else on Earth and new species are discovered there all the time. Between 1999 and 2009 alone, researchers catalogued more than 1,200 new species there the equivalent of a new species every three days.

The Amazon is the world's largest remaining rainforest, and its trees under threat of deforestation by logging operations and agriculture store between 90 billion and 140 billion tons of carbon. This carbon-holding capacity makes the rainforest a valuable carbon sink at a time when greenhouse-gas levels have reached record highs.

The tremendous amount of photosynthesis that goes on in the rainforest produces some 20 percent of Earth's oxygen a very good thing for those of us who breathe it. All that oxygen production has earned the rainforest the moniker of the "lungs of the Earth."

The Juruá River snakes slowly through the half-flooded Amazon rainforest in western Brazil, leaving free-standing oxbow lakes in its wake, which form when a river changes course as it meanders through a floodplain.

The Juruá is the most winding river in the Amazon basin and one of the Amazon River's longest tributaries, exceeding 2,040 miles (3,283 kilometers) in length. Tropical rainforests have some of the largest rivers in the world because of the tremendous amount of precipitation their watersheds receive.

Given its size, remote sensing is the best way to study the Amazon Basin on a large scale — especially for assessing the extent and damage due to deforestation.

This image is a compilation of three images taken by the Envisat satellite on January 2, February 1 and March 3, 2012. The individual images are each assigned a color — red, green and blue — and when combined, reveal changes in the surface between the satellite's passes.

Satellite radar data can be manipulated to map forest height, 3D forest structure and their changes due to natural or man-made disturbances from deforestation.  

Since forests assist in removing carbon dioxide from the atmosphere, this could prove to be an important tool for assessing carbon stocks and monitoring our planet's resources.

Following ten years of service, Envisat stopped sending data to Earth on April 8 and after attempts to re-establish contact, the mission was declared over by the European Space Agency.

Follow OurAmazingPlanet for the latest in Earth science and exploration news on Twitter @OAPlanet. We're also on Facebook and Google+.

An underground river has now been discovered beneath the mighty Amazon River, flowing miles below the surface.

Scientists detected this river after they analyzed data from 241 wells that Brazilian oil company Petrobras drilled in the Amazon region in the 1970s and 1980s. The river was unofficially named the Hamza by scientists at Brazil's National Observatory in honor of their colleague, geophysicist Valiya Hamza.

"The name given to the underground flow is not official," Hamza said.

Thermal signatures of groundwater suggest that the Hamza flows west to east just like the Amazon, except at a depth of about 13,000 feet (4,000 meters) below the Earth's surface. Computer simulations suggest that at a higher depth of about 2,000 feet (600 meters), the river actually flows vertically.

Much less water flows down the Hamza than the Amazon — about 1 million gallons (3,900 cubic meters) per second as opposed to about 35 million gallons (133,000 cubic meters) per second for the Amazon. Water also crawls more slowly down the Hamza, with speeds of about 33 to 330 feet (10 to 100 meters) per year, as opposed to the Amazon's swift water speeds of about 20 to 390 feet (6 to 120 meters) in just one hour.

Still, the Hamza is nearly as long at about 3,700 miles (6,000 kilometers) compared to the Amazon's length of about 3,800 miles (6,100 km). The Hamza is also much broader at about 125 to 250 miles (200 to 400 km) wide, compared to the Amazon's width of about 0.6 to 60 miles (1 to 100 km).

The Hamza might not be the only such subterranean flow.

"It is possible that underground river systems of a similar kind exist in other parts of the Earth," Hamza told OurAmazingPlanet.

Altogether, these findings reveal "there are three kinds of 'river systems' in the Amazon region," Hamza said. In addition to the well-known Amazon River and its tributaries, there are "atmospheric rivers" where large amounts of water vapor flow through the local air and now this underground river system. Knowing about these three flows helps scientists better understand the total amount of water available in the Amazon region, which is a critical factor for investigating life there.

Hamza and Elizabeth Tavares Pimentel detailed their findings Aug. 17 at the International Congress of the Brazilian Society of Geophysics in Rio de Janeiro.

This story was provided by OurAmazingPlanet, a sister site to LiveScience.

Brazilian officials have confirmed the existence of approximately 200 Indians who live in the western Amazon with no contact with the outside world.

This uncontacted tribe is not "lost" or unknown, according to tribal advocacy group Survival International. In fact, about 2,000 uncontacted Indians are suspected to live in the Javari Valley where the tribe's homes were seen from the air. But confirming the tribe's existence enables government authorities to monitor the area and protect the tribe's way of life.

In 2008, Survival International released photos of another uncontacted tribe near the Brazil-Peru border. The striking images revealed men aiming arrows skyward at the plane photographing them. Uncontacted Indian groups are aware of the outside world, a Survival International spokesperson told LiveScience at the time. But they chose to live apart, maintaining a traditional lifestyle deep in the Amazon forest. The latest images reveal that the newly confirmed tribe grows corn, peanuts, bananas and other crops.

Because the tribes are so isolated, contact with the outside world can be deadly. Survival International's website, http://www.uncontactedtribes.org/, tells the story of the uncontacted Zo'e tribe. When missionaries contacted the tribe in 1987, 45 Indians died of common diseases that they had never encountered and thus had no tolerance for, including the flu. In Peru, half of the previously uncontacted Nahua tribe died of disease after oil exploration began on their land in the 1980s.

Nearby oil exploration in Peru also threatens the newly confirmed tribe, Fabricio Amorim of Brazil's Indian Affairs Department said in a statement.

"Among the main threats to the well-being of these groups are illegal fishing, hunting, logging, mining, cattle ranching, missionary actions … and drug trafficking," Amorim said.

You can follow LiveScience senior writer Stephanie Pappas on Twitter @sipappas. Follow LiveScience for the latest in science news and discoveries on Twitter @livescience and on Facebook.

This ScienceLives article was provided to LiveScience in partnership with the National Science Foundation.

Robert Walker is a professor of Geography at Michigan State University, with a Ph.D. in Regional Science from the University of Pennsylvania. He grew up in Florida, where he learned to value the wilds of nature, but also saw the price of poorly planned development. Walker studies land-cover change, and in particular the loss of tropical forests in Amazonia. His research approach is one of "boots on the ground," and he draws intellectual nourishment from grueling field campaigns in Amazonia (the Amazon rain forests). In conducting his research, Walker has spoken with thousands of frontier residents, including farmers, ranchers, loggers, gold-miners, Indians and fellow adventurers. In the process, he's traveled by jeep down many of the roads in the region, logging thousands of miles. Walker cannot imagine a summer without an opportunity to rough-it south of the border, but he is always thankful to return home to his wife and family in Michigan, and the rejuvenating waters of the Great Lakes. Read Walker's response to the ScienceLives 10 questions below.

Name: Robert Walker Age: 59 Institution: Michigan State University Field of Study: Geography and Environment

What inspired you to choose this field of study? I was inspired to study environmental problems by my personal experiences with environmental degradation in the State of Florida, where I grew up. I saw firsthand the obliteration of pine flatlands, mesic hammocks, mangrove estuaries, and coral reefs, and I could never understand why people would want to exchange the wildness of the landscape for a built environment. I also witnessed the channelization of the Kissimmee River to make way for Disney World, which seemed completely illegitimate to me as a child. Through the 1950s and 1960s, I saw Florida change from a beautiful tropical-subtropical paradise to a land of strip malls, theme parks and modular housing. It was enough to make me care, and leave. I know that people need to impose on nature for subsistence and livelihood. I also know that they need nature for other purposes. 

What is the best piece of advice you ever received? My best piece of advice was that one must never give up, or admit defeat, in pursuing a cherished objective. Someone once told me that success is the ability to persist in the face of continuous failure. This is my motto, and it has sustained me through proposal review cycles, manuscript rejections, and sleepless nights wondering where the funds will come from to continue my work.   

What was your first scientific experiment as a child? My first scientific experiment involved a science fair project examining the life cycle of shipworms. When all of them died in my aquarium, I changed my experiment to a study of the link between mortality and salinity.

What is your favorite thing about being a researcher? My favorite thing about being a researcher is being allowed to let my mind wander, and to see patterns and symmetry that I hadn't seen the day before. I often wake in the morning, wondering what new insights will greet me through the course of the day. I have the same sensation when sitting down to a manuscript in preparation, knowing that a blank page is also a field of thought, and therefore a pleasure. A researcher's life is a life of continuous imagination.

What is the most important characteristic a researcher must demonstrate in order to be an effective researcher? The most important characteristic is persistence, combined with single-minded purpose. Intelligence plays a role, but much less than one might imagined.

What are the societal benefits of your research? The societal benefits of my research are that it affords insight into a process of environmental change of global concern, namely the loss of our tropical forests. To be effective in addressing problems, policy must be based on an understanding of the human beings whose actions lie at their root. This is especially so with deforestation, for trees hardly fall down in massive clear-cuts of their own volition. Environmental policy, in this case, must incentivize people away from such actions, which can only be done if it is known why they engage in them in the first place. 

Who has had the most influence on your thinking as a researcher? I can mention three people here. The first was Howard Odum, the ecologist, who taught me that the world is a system of systems of systems, ad infinitum. The second was Daniel Vining, a social scientist at the University of Pennsylvania. He taught me to question everything and assume nothing, to approach problems from the ground up, to distrust received wisdom. The third was Ronald Miller, an operations research specialist, also at the University of Pennsylvania. He taught me mathematics, and gave me the desire to translate what I saw into logical structures.

What about your field or being a researcher do you think would surprise people the most? I think it would surprise people to realize how little is actually known about the world we live in, that there are research frontiers in every direction. I think it would also surprise people to realize that methodology is hardly fixed, that scientific approaches all have a seat-of-the pants component, that guess work and inspiration play huge roles in any scientific endeavor. I remember talking with a politician maybe ten years ago about deforestation. He was astonished when I told him there was controversy about rates of forest loss. He assumed that because it was such a global problem, the science would have been completely nailed down, end of story. He wasn't that interested in learning about measurement error, or problems with cloud-cover, either. Not to mention all the disagreements about what was causing the problem.   

If you could only rescue one thing from your burning office or lab, what would it be? I would quickly download all of my manuscripts and data onto an external drive, and run like hell. I know I'm only allowed to take one thing here, but on my dash from the office I'd also grab an armful of Brazilian books, documents, and maps that are impossible to come by in libraries or stores in the United States, stuff it's taken me years to collect through opportune encounters, or purchases in remote places.

What music do you play most often in your lab or car? I play Brega, which is a working-class Brazilian music from the Amazonian gold-mines. It's fast-paced and rather raunchy, and would never be aired in the United States if the songs were sung in English, because the lyrics can be crude. In fact, Brega is slang for "low-class." But, the music's great, whether by Banda Calypso, Banda da Lourinha or even Fruta Sensual.

To learn more about Walker's research in the Amazon, check out this National Science Foundation article and an article in the Michigan State University Alumni Magazine. Watch a video below describing Walker's research and experiences in the Amazon.

Editor's Note: This research was supported by the National Science Foundation (NSF), the federal agency charged with funding basic research and education across all fields of science and engineering. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. See the ScienceLives archive.