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

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

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

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

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

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

It’s all about ice

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

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

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

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

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

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

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

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

Scientific and Indigenous observations

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

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

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

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

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

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

Something surprising has been happening to polar bears. Those living in Svalbard, a Norwegian archipelago, have been gobbling up hundreds of birds' eggs and looking healthier than they have in the past. And in warmer parts of Greenland, the bears are showing signs of genetically adapting to climate change.

The discoveries seem to be unexpected bright spots for the beleaguered species, which for decades has been photographed clinging to vanishing sea ice and has become a "poster animal" for the effects of climate change. So what do the promising signs mean for polar bears? Could they actually survive the rapid melting of Arctic sea ice?

Experts told Live Science that the new findings show there may be unexpected refuges where some polar bear populations cling on or even do well for longer than models suggest. Alone, these discoveries won’t be enough to save polar bears from extinction, but they might buy these iconic creatures a little more time as the world attempts to do the one thing that could save them — cutting emissions.

An icebound creature

The future for polar bears (Ursus maritimus) has looked precarious for a long time. The animals depend on sea ice, on which they hunt ring seals (Pusa hispida) and bearded seals (Erignathus barbatus), which can outswim the bears in the water. As the climate warms, sea ice is melting, shrinking this key hunting ground. A 2020 study projected that if greenhouse gas emissions continue as usual, all but a few polar bear populations will collapse by 2100, with the remaining ones clinging on for longer in a handful of "last refuges" such as the Queen Elizabeth Islands, Canada's northernmost Arctic archipelago.

Yet the recent positive findings raise the tantalizing prospect that polar bears might be able to survive climate change after all.

A January study in the journal Scientific Reports looked at the body condition of 770 adult polar bears in Svalbard between 1995 and 2019. They found that, on average, the bears became thinner until 2000 but grew fatter afterward, despite a rapid loss of sea ice there.

That was a surprise, because a fat polar bear is a healthy one, lead researcher Jon Aars, a research scientist at the Norwegian Polar Institute in Tromsø, told Live Science. "We expected to see a decline in body condition because of the rapid loss of sea ice."

And a study published in the journal Mobile DNA in December 2025 revealed that polar bears in southern Greenland are using "jumping genes" to rapidly rewrite their own DNA, potentially allowing them to more readily adapt to warmer habitats by changing how they handle heat and process fats.

Mixed picture

So do these findings really mean the picture is looking less bleak for polar bears?

Andrew Derocher, a biologist at the University of Alberta who worked with Aars on the Svalbard bear study, told Live Science that there are 20 unique polar bear populations around the Arctic, and each lives in a slightly different environment and faces a different level of sea ice loss.

"The basic premise is that if you lose the sea ice, the bears are losing habitat," he said. "They're forced on land for longer. They use up more energy, and then they get in poorer condition, with knock-on effects on survival and reproduction." But there is an incredibly productive ecosystem between the islands in the Svalbard area and those in the Russian Arctic near Franz Josef Land.

Because the area is on a continental shelf, the water off Svalbard is relatively shallow and warm, with nutrient-rich water flowing in from the North Atlantic, he said. This means polar bears have lots of prey options. They are eating walruses, birds and even birds' eggs, and they're staying in good shape.

"In dense colonies of ground-nesting birds like ducks and geese, bears have been seen taking a couple of hundred eggs during a single day," Aars said. "They just raid quite a lot of the nests, eating absolutely everything."

And although seal numbers in Svalbard are down, where there is ice, the seals sit on it in higher density, which may make them easier to catch, Derocher said. Sometimes the Svalbard bears have even been spotted catching reindeer (Rangifer tarandus platyrhynchus).

Unfortunately, there are not enough reindeer to sustain a population of polar bears, he said. "So, no matter how wonderful those pictures look when they're scarfing down a reindeer, it's not going to help them."

The new insights highlight polar bears' resourcefulness, said Louise Archer, a polar bear scientist at the University of Toronto Scarborough.

"What we're seeing happening in Svalbard is really interesting in terms of all the different behaviors that polar bears can employ to deal with their changing environment," Archer told Live Science.

But their shift to hunting birds' eggs, walruses and reindeer doesn't mean they are developing evolutionary adaptations to an ice-free world.

"They've always done that," Derocher said. "They're just being forced to do it more."

It's clear that a permanent land relocation is unlikely, because they move onto the ice as soon as it reappears, he added. "Sea ice is what makes a polar bear possible," Derocher said. "It's the high fat diet from the abundance of seals that allows them to exist in an incredibly cold environment."

Body condition also isn't the whole story, he said. Svalbard's polar bears may be in good shape, but they reproduce on ice. Because large areas of Svalbard's west coast are now free of sea ice, key areas in which they build dens have disappeared. A December 2025 modeling study estimated that reproduction and cub survival will decline around Svalbard in low-ice years. "The ice just doesn't come in time," Derocher said.

Genetic adaptation?

But is there hope in the news that some polar bears seem to be genetically adapting to warmer climes? Alice Godden, a bioscientist at the University of East Anglia, and her colleagues looked at genetic elements that can copy and paste and jump around the genome, causing mutations, in subpopulations of polar bears in northern and southern Greenland. They found more of this genetic activity in the southern population, where it is warmer.

Many of the changes in gene expression were in metabolic pathways that govern fat processing, so they could be reactions to warmer weather and a changing diet. It's a promising sign that the bears are adapting, Godden said, but the time scale required for such changes to make a meaningful difference is longer than the time polar bears are thought to have left.

The majority of the Arctic Ocean could be ice-free during summer by 2050, but as the length of a polar bear generation is about 11.5 years, genetic adaptations to an ice-free ecosystem will likely take many hundreds or thousands of years, Godden said.

"They're adapting as best they can, but without human intervention, the odds aren't looking great," she said.

Derocher, for his part, suspects the genetic changes may not be adaptations at all but rather a sign the bears are more stressed, which can lead to DNA damage and thus more mutations, essentially causing faster biological aging.

Patches of hope in an overall bleak picture

Ultimately, some polar bear populations may do better than others, depending on local geography, food availability and sea ice dynamics. "We suspect that it's going to be 20 different subpopulations, 20 different scenarios, all kind of following the same trajectory but at different sort of time scales," Derocher said.

Aars agreed. "I think the likely thing is that polar bears will disappear from much of the Arctic as sea ice recedes further and further north, but it's very, very difficult to say how fast it goes," he said.

Archer expects populations to plummet earlier in regions like Western Hudson Bay, Southern Hudson Bay and western Canada, which lacks a rich ecosystem and where bears already spend several months without sea ice.

But as the Svalbard news shows, there are potential refuges where the bears could hold out for longer. In other parts of the High Arctic, such as around the Canadian Arctic Archipelago, there is still very thick sea ice, which allows little light to penetrate to the water and therefore little energy to support a food chain. As this ice starts to thin, more algae will grow, supporting communities of invertebrates, fish and seals that can feed polar bears, which may allow them to remain in these areas beyond the end of the century, Archer said.

How long Svalbard could sustain a viable population of bears isn’t certain. “Are the Svalbard bears going to get hit by a devastating warm year next year, the year after, or can they go like this for 20 more years before things get really bad?” Derocher said.

Ultimately, the odds of these iconic bears surviving beyond the end of the century will depend mainly on reducing emissions. "There are some changes that are already baked into the system, but there's a lot that we can do to alter what the future looks like for them."

For example, if we limit global warming to 3.7 degrees Fahrenheit (2 degrees Celsius) above pre-industrial levels then adult polar bears could survive to 2100, even at the southern end of their range in Hudson Bay, Archer said.

“We are not on an unstoppable trajectory towards a tipping point where sea ice disappears for good,” Archer said. "It’s absolutely in our hands how the future plays out.”

Stunning images showing a deer carrying a rival's rotting head and a lynx playing with its food are among the shortlisted entries for an annual wildlife photography competition's people's choice award.

The Wildlife Photographer of the Year Nuveen People's Choice Award 2026 is hosted by the Natural History Museum in London. Anyone anywhere in the world can now vote for their favorite photograph online.

Other image highlights include a "superpod" of spinner dolphins (Stenella longirostris) driving their food to the ocean surface, and a tiger (Panthera tigris) with a rare genetic condition resulting in wide, dark stripes.

Two heartbreaking images of polar bears (Urus maritimus) are also among the shortlist: One photo shows a mother and her three cubs napping on the bare ground in Canada's summer heat, and the other captures a cub on a hunting trip in Svalbard that took a tragic turn when the cub and its mother roamed too close to a human settlement.

Voting closes March 18, and the winning photograph will be announced March 25. It will be displayed along with 100 images from last year's Wildlife Photographer of the Year competition in an exhibition at the Natural History Museum, London open until July 2026.

Wildlife Photographer of the Year is developed and produced by the Natural History Museum, London. Don't forget to let us know in the comments which image is your favorite.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Bears are a type of mammal that can be found in many parts of the world. From the tiny, silly-looking sun bear to the iconic polar bear, these animals are specially adapted to different environments, including forests, mountains, icy tundra, deserts and swamps. Though there are different types of bear, all bear species have similarities. They all have stocky, fur-covered bodies; short legs; and a round head with a long snout. Whether the word "bear" makes you think of a fierce predator or a cuddly stuffed toy, there's plenty to discover about the science behind this diverse group of mammals.

5 fast facts about bears

• Panda bears poop 40 times per day.
• When they're first born, bear cubs weigh less than 2 pounds (0.9 kg).
• Bears that snack on honey have thick skin and fluffy fur that protects them against bee stings.
• Because polar bears spend so much time on the water, they're classified as marine mammals.
• Bears have a great sense of smell that helps them sniff out food.

Everything you need to know about bears

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—Polar bears: The largest land carnivores

—Black bears: The most common bear in North America

—Sun bear: The little carnivores that look so similar to humans they've been mistaken for people wearing costumes

Researchers have captured extremely rare footage of polar bear cubs leaving their snowy dens for the first time.

The footage, taken on the Norwegian archipelago Svalbard, shows a mother polar bear (Ursus maritimus) plodding through the Arctic island's frozen landscape and her three cubs emerging one after another from a hole in the ice, before slipping and sliding around the frozen terrain.

The scene is from one of 13 den sites on Svalbard that scientists have been monitoring for nearly a decade to shed light on denning behavior, which is notoriously difficult to study because polar bear moms build the dens underground in hard-to-access areas.

The researchers described new aspects of denning behavior in a paper published Thursday (Feb. 27) in The Journal of Wildlife Management.

"It's a pretty special thing to see polar bear cubs emerge into this vast, white landscape that appears so inhospitable," lead author Louise Archer, a Polar Bears International postdoctoral fellow at the University of Toronto Scarborough, told Live Science in an email.

Related: Polar bears are getting horrific injuries and huge 'ice balls' on their paws because of climate change, researchers say

"In Svalbard, polar bears build their dens on the slopes of steep mountainous areas, and it's hard to imagine how cubs could find their feet in this severe terrain," Archer said. "Watching them sliding, tumbling, and even climbing up on their mother was truly remarkable."

The new study offers a glimpse at one of the most vulnerable and critical periods of a polar bear's life, researchers said in a statement.

Polar bears spend the winter in their dens. Pregnant females give birth around early January and nurse their cubs through spring, when the family emerges to slowly make its way to the sea ice. Newborn polar bears are hairless and weigh just 1 pound (0.5 kilograms). However, they grow quickly thanks to their mother's fatty milk and reach 22 pounds (10 kg) by the time they emerge as cubs.

Maintaining healthy polar bear populations depends on cubs' survival, which is only around 50%, according to the statement. Cubs survive only if their dens remain undisturbed throughout the winter and they can roam the surrounding area after emerging. Human activity jeopardizes both of these requirements.

"Polar bear mothers are having increasing difficulties reproducing due to climate-driven changes, and are likely to face further challenges with the expansion of the human footprint in the Arctic," Archer said in the statement.

To assess human influence on polar bear reproduction, researchers need to better understand denning behaviors and timings. A decade ago, Archer and colleagues fitted 13 female bears with GPS collars that recorded the animals' locations, body temperatures and levels of activity. The researchers used this data to locate the bears' dens, before traveling to Svalbard to install camera traps outside them.

The study is the first to combine collar data with camera footage of polar bears. "Every den we monitored had its own story," Archer said.

Throughout the study period, the moms and cubs first emerged in early March, sometimes venturing out for just a few minutes before returning to their dens. The families abandoned their hideouts earlier than previously recorded on Svalbard, but more observations are needed to confirm if this is a new trend, according to the statement.

The bears remained near their dens for an average of 12 days before heading off toward the sea ice, where mothers teach their cubs to hunt. The cubs stayed with their moms 95% of the time, rarely leaving the den alone. On Svalbard, cubs remain with their mother for 2.5 years after birth, according to the statement.

The researchers couldn't follow the bears once they left the den site. "I would love to know how the polar bear families we monitored fared once they departed the den," Archer told Live Science by email. "How soon does the mother catch a seal, [and] do her cubs manage to survive those initial few weeks when they venture out on the sea ice?"

Polar bears are currently snuggled up their dens, but it won't be long before they emerge again. Archer and colleagues are in Svalbard now, collecting information that may help them fill these gaps.

"We're excited to introduce new tools to monitor bears during this vulnerable time and to gain insight into their behavior across the Arctic," Archer said in the statement.

This striking satellite shot shows a pair of simultaneous phenomena painting parallel swirls in the sea and sky surrounding Bear Island. The isolated land mass, also known as Bjørnøya, is located in Norway's Svalbard archipelago and is surrounded by highly radioactive waters that may endanger local wildlife — which, ironically, does not include many bears.

In the upper left corner of the image, a gap in the clouds is trailed by a series of interlinked cloud swirls that appear to have been platted together like a pretzel. These swirls, known as von Kármán vortices, are formed when clouds get caught up in an airflow that has been disrupted by a tall landmass, most often above an ocean, according to NASA's Earth Observatory.

In this case, the vortices are created by clouds passing over Miseryfjellet, the largest mountain on Bear Island. Miseryfjellet, which translates to "misery mountain," has three peaks: Urd, Verdande and Skuld, named after a trio of deities from Norse mythology, known as the Norns. The tallest peak, Skuld, stands around 1,759 feet (536 meters) above sea level.

In the center of the image, a gigantic bloom of photosynthetic algae, or phytoplankton, can be seen swirling near the surface of the Barents Sea. The light green hues of the algal artwork are the result of chlorophyll — the pigment in algae and plants that allows them to convert sunlight into energy, via photosynthesis. The spiraling shapes of the bloom, which spans up to 250 miles (400 kilometers) across, are the result of ocean currents.

Related: See all the best images of Earth from space

The simultaneous appearance of von Kármán vortices and the algal bloom is a complete coincidence and the two phenomena are in no way connected, according to Earth Observatory.

Bear Island

Dutch explorers first discovered Bear Island in the late 16th century and named it after a polar bear (Ursus maritimus) that was seen swimming nearby. However, polar bears are rarely seen on the island, which is one of the most southern points in Svalbard and is rarely accessible to the white bears via Arctic sea ice.

For example, in 2019, researchers stationed at the Bjørnøya weather station spotted a polar bear for the first time in more than 8 years, according to PolarBearScience.com.

Instead, the island's most abundant residents include foxes, seals and seabirds. In total, around 1 million seabirds gather along the island's cliffs every year during the breeding season, according to Earth Observatory.

However, in recent years, fears have been raised about how these birds and the rest of the island's ecosystem could be impacted by an unusual spike in radioactivity leaking from a Cold War-era nuclear submarine, K-278 Komsomolets, which sunk to the seafloor in 1989 roughly 115 miles (185 km) southwest of Bear Island.

In 2019, the BBC reported that the levels of radiation in the water surrounding the submarine were 800,000 times higher than normal, thanks to continued leakage from the vessel's reactor. However, it is still unclear whether this could be impacting the wider marine environment.

Polar bears are developing horrific wounds on their paws due to changing ice conditions in the Arctic, a new study reports.

In the most severe cases, researchers describe two bears with crippling, dinner plate-size balls of ice stuck to their feet. Beneath the ice balls, the bears' paw pads were covered in deep, bleeding cuts.

"I'd never seen that before," study lead author Kristin Laidre, a marine ecologist and associate professor at the University of Washington, said in a statement. "The two most-affected bears couldn't run — they couldn't even walk very easily."

This is the first time scientists observe such injuries in polar bears, according to the study, published Oct. 22 in the journal Ecology.

The debilitating ice balls likely formed due to slushy snow sticking between bumps on the pads that provide the grip polar bears need to walk on slippery surfaces. Snow accumulated on the pads and then froze solid, the researchers suggest, forming blocks of ice measuring 12 inches (30 centimeters) across.

Related: Bleak photo of polar bear with plastic in its jaws in the remote Arctic shows pollution's 'pervasive grip'

"The chunks of ice weren't just caught up in the hair," Laidre said. "They were sealed to the skin, and when you palpated the feet it was apparent that the bears were in pain."

Researchers say roughly one in four polar bears (Ursus maritimus) from two populations in northern Greenland whose feet they examined suffered from ice-related injuries. Affected bears were mostly adult males, which tend to travel longer distances and are much heavier than females or cubs.

Laidre and study co-author Stephen Atkinson, a wildlife biologist and veterinarian, examined polar bears from populations in East Greenland and Kane Basin — a waterway between Greenland and Canada's northernmost island, called Ellesmere Island — between 2012 and 2022. They captured the animals as part of standard population assessments, sedating them before conducting routine health checks.

Thirty-one of 61 bears in the Kane Basin population had laceration, skin ulceration, hair loss or ice buildup on their paws. Between 2012 and 2013, 73% of adult males in this population were affected, according to the study. In the East Greenland population, between 2018 and 2022, 15 of 124 polar bears displayed similar injuries.

The researchers proposed several explanations for the wounds and interviewed Indigenous hunters to identify potential causes. Ice buildup and lacerations may result from rising temperatures in the Arctic, with warm spells leading to wet snow and freeze-thaw cycles that create brittle ice on which polar bears cut their feet, the scientists suggested.

Climate change is leading to more frequent rainfall in the Arctic, turning snow into slush that becomes lodged in polar bears' paws, where it freezes, they wrote in the study. Warmer temperatures also cause the surface snow to melt and then refreeze into a hard crust, which heavy polar bears break when they trample over it, injuring themselves.

Indigenous hunters in Kane Basin knew about the lesions on polar bears' feet and attributed them to increased movement during the mating and hunting season. But the hunters also recognized these injuries as a recent phenomenon. They mentioned that wet snow conditions negatively impact sled dogs, too. According to the study, the hunters noted they now have to trim the hairs between their dogs' pads to prevent ice buildup and lameness.

John Whiteman, an assistant professor of biology at Old Dominion University in Virginia and chief research scientist at the non-profit organization Polar Bears International, said he has never seen or heard about these types of injuries before.

"This report is definitely surprising," Whiteman, who was not involved in the new study, told Live Science in an email. "If the conditions that encourage ice clumps become a common occurrence across a large area, more bears would be at risk for foot damage."

An image capturing a polar bear with plastic hanging from its jaws has been shortlisted for the Ocean Photographer of the Year 2024 award. The image, taken on Kiepert Island in the Svalbard archipelago off Norway, by photonaturalist Celia Kujala serves as a "a stark reminder that even the uninhabited reaches of the Arctic are not exempt from the pervasive grip of plastic pollution," competition representatives wrote in a statement emailed to Live Science.

The photograph is shortlisted in the Ocean Conservation Photographer of the Year (Impact) category, which also includes a photo of a dead fin whale waiting to be butchered at a facility in Iceland, shark fins drying on a roof in Indonesia and a gannet, a large white seabird with a yellowish head, trapped in discarded fishing gear hanging from a cliff.

The polar bear (Ursus maritimus) photograph highlights the scale of plastic pollution in the Arctic and the impact it has on regional species. Considered vulnerable by the International Union for Conservation of Nature Red List of Threatened Species, polar bears face multiple threats. A 2016 study predicts their numbers will fall by 30% by the middle of the century.

Climate change is the primary threat, reducing the sea ice on which they hunt. However, plastic is compounding the problem. Polar bears are increasingly turning to landfills for food. An analysis of polar bear stomach contents from the population in the Southern Beaufort Sea off Alaska and Canada found 28% contained plastic. Half of the bears that had eaten plastic also had acute gastritis, potentially leading to painful blockages in their digestive system.

Related: Polar bear sleeping on tiny iceberg drifting in Arctic sea captured in heartbreaking photo

"There are not enough data to get a clear picture, but it is probable that bears are more likely to ingest plastic when they find human trash as they seek food on shore," John Whiteman, chief research scientist at Polar Bears International and assistant professor of biology at Old Dominion University in Virginia, told Live Science in an email.

"Sea ice loss, and the resulting increase in time spent on land, is making it ever more important to find safe, long-term ways to manage trash — an issue that multiple Arctic communities have tackled with success," he added.

The winners of the Ocean Photographer of the Year 2024, presented by Oceanographic Magazine and Blancpain, will be announced on Sept. 12. Shortlisted images for the Ocean Conservation Photographer of the Year (Impact) category can be seen below.

A heart-wrenching image captures a young polar bear napping on the melting scraps of a tiny, drifting iceberg.

British amateur photographer Nima Sarikhani captured the scene off the Norwegian archipelago of Svalbard, which sits deep inside the Arctic Circle, around 500 miles (800 kilometers) from the North Pole. The image was crowned the winner of this year's Wildlife Photographer of the Year People's Choice Award.

After three days of desperately searching for polar bears (Ursus maritimus) through thick fog, the expedition vessel that Sarikhani was on changed course and sailed southeast toward some sea ice. There, the crew spotted two polar bears — a younger and an older male. Just before midnight, as the ship hovered close to the bears, the younger one climbed onto a small iceberg and carved out a bed with his paws before drifting off to sleep. 

"This photograph has stirred strong emotions in many of those who have seen it," Sarikhani said in a statement shared with Live Science.

Members of the public voted "Ice Bed" as the competition winner from a shortlist of 25 images curated by a panel of judges and the Natural History Museum in London.

"Nima's heartbreaking and poignant image allows us to see the beauty and fragility of our planet," Douglas Gurr, director of the Natural History Museum, said in the statement. "His thought-provoking image is a stark reminder of the integral bond between an animal and its habitat and serves as a visual representation of the detrimental impacts of climate warming and habitat loss."

Related: 'This is unlikely to be an isolated event': 1st polar bear death from bird flu spells trouble for species

Climate change is considered the biggest threat to the survival of polar bears in the wild, as rising temperatures melt away the sea ice these animals depend on. An estimated 26,000 polar bears remain in the wild, according to the International Union for Conservation of Nature Red List of Threatened Species, and they are considered vulnerable to extinction. 

"Whilst climate change is the biggest challenge we face, I hope that this photograph also inspires hope," Sarikhani said. "There is still time to fix the mess we have caused."

The winning photograph will be displayed alongside four other "highly commended" images both online and in the Wildlife Photographer of the Year exhibition at the Natural History Museum until June 30. The shortlisted photographs can be seen below.

Wildlife Photographer of the Year is developed and produced by the Natural History Museum, London.

The world's unofficial polar bear capital, could see a record number of the white-furred visitors this year. Residents of Churchill, Canada, have already spotted an unusually high number of the bears in and around  town, likely because of low sea ice.

Around 900 people live in the Manitoba town. But every year, between July and November, several hundred polar bears (Ursus maritimus) descend on the town and the surrounding Hudson Bay area, which also brings in thousands of tourists hoping to catch a glimpse of the Arctic predators. 

Conservation officers from the town's government-funded Polar Bear Alert Program (PBAP) respond to calls from people who spot bears by either shooing the bears away or capturing them and holding them in Churchill's polar bear holding facility, commonly referred to as the "polar bear jail," before later releasing them into the wild.

As of Aug. 16, PBAP officers had received 76 calls from residents about polar bears, which have led to three bear detentions. By comparison, the officers had received only 18 calls and captured zero bears by the same time last year, CBC News reported.

"There are so many polar bears in and around the town of Churchill," Chantal Maclean, a Manitoba conservation officer with the PBAR, told CBC News. It's going to be a "very busy bear season," she added. "We are [potentially] looking at record numbers this year."

Related: In 'extremely rare' attack, polar bear killed mother and child in Alaska. Now we know why.

On average, officers receive around 250 calls from residents and detain around 50 bears every year, according to statistics provided to Live Science by the Manitoba government. The record number of bears captured in a single year was 176, in 2003. Most sightings occur in October and November, which means the number of sightings this year could easily surpass the average if the current trend continues.

Two people in Churchill have been killed by polar bears — one in 1968 and another in 1983. The last polar bear attack was in 2013, when two people were severely injured but survived. The rise in polar bear numbers does not necessarily mean chances of attacks increase, especially if people follow polar bear guidelines, officers said.

Rising numbers

Polar bears spend the winter hunting for seals on Hudson Bay's frozen surface. When the ice melts during spring, the bears head inland to mate and search for alternative food sources. In the fall, the bears head back out to sea. Normally, around half of the roughly 600 bears that live along Hudson Bay's western coastline pass through Manitoba as they return to the frozen waters in fall — and a majority of those make a pit stop in Churchill to look for food. The rest pass through Ontario and Nunavut.

But this year, almost all of the Hudson Bay bears that conservation officers monitor are in Manitoba, which may be why so many bears are being spotted in Churchill.

The likely cause of the change in behavior is the way sea ice is forming and melting, which has been impacted by human-caused climate change. Experts believe that the sea ice near Churchill is now freezing earlier than other parts of Hudson Bay, which makes it the best place to start hunting when winter arrives, CBC News reported.

Polar bear numbers in Churchill may be on the rise, but in general polar bear numbers are declining. The species is currently listed as vulnerable on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. Studies have predicted that polar bears could be wiped out by the end of the 21st century if current warming trends continue.

Over the last five years, Hudson Bay's population of polar bears has declined by around 27% after falling by around 11% in the five years before that, according to Polar Bears International. 

Polar bear twins have been reunited in a zoo after more than two years apart. The siblings were separated shortly after birth when one of them developed severe health problems and was later rejected by their mother.

The female polar bears (Ursus maritimus), named Astra and Laerke, were born at Detroit Zoo on Nov. 17, 2020 to mother Suka and father Nuka. But two days later, Laerke was separated from the den she shared with her mother and sister due to a medical emergency, which required keepers to hand-feed her and monitor her around the clock. After making a full recovery, zoo staff attempted to slowly reintegrate Laerke with Suka and Astra — but it did not go to plan. 

"Suka was very protective of her cub, Astra, and acted aggressively toward the cub she no longer recognized as her own," Detroit Zoo representatives told Live Science in an email. Laerke remained in a separate enclosure during the reintegration process and "was never at risk of being injured" by the mother, they added.

Astra and Suka were moved into separate enclosures in January this year after Astra reached the age when polar bears leave their mothers in the wild. This gave zoo staff the opportunity to reunite Astra with her twin, who grew up alongside an abandoned grizzly bear named Jebbie.

Related: Secret population of polar bears found living in seemingly impossible habitat

After a brief period of reintegration, where the pair met and interacted with one another in adjoining cages, zoo keepers let Laerke into Astra's new enclosure on April 11. The reintroduction went extremely well and "the sisters appear to enjoy sharing a space," the zoo representatives said. They hope the pair can remain together full-time, the representatives added. 

On April 17, the zoo shared heartwarming images of Astra and Laerke playing together on Facebook along with the caption "sister, sister — never knew how much I missed ya."

Keepers will continue to closely monitor the pair in the coming weeks. They expect that after becoming familiar with one another, the twins may spend less time together, which is normal because adult polar bears tend to keep to themselves in the wild.

Laerke's story is quite a common one in zoos. 

On Feb. 27, Born Free — a U.K.-based charity that advocates for relocating captive animals to the wild, as well as improving their quality of life — released a report into the issues associated with keeping polar bears in captivity. Along with concerns about reduced lifespans, improper diets and a lack of space to roam, the report said captive cubs are more likely to die or develop health complications in captivity, with less than half surviving past 30 days. 

When humans step in to save them, mothers can end up rejecting their babies. This is likely because mothers are more stressed when giving birth in captivity than in the wild, according to the report.

However, Polar Bears International, a non-profit conservation organization, says zoos and aquariums also play an important role in conserving polar bears. 

Captivity will also play an important role in preserving the species for future generations to appreciate because climate change is expected to wipe out most wild populations, potentially as early as the end of this century. 

Last month, a polar bear killed a woman and her 1-year-old child in Alaska. It was the first fatal polar bear attack recorded in the U.S. in more than 30 years. Now, a new report sheds light on what may have caused the tragic event. 

Experts analyzed the animal's tissues, which revealed that the male bear was in poor physical shape and likely elderly. However, it's unknown exactly what triggered the polar bear's (Ursus maritimus) aggressive behavior. 

Summer Myomick, 24, and her infant son, Clyde Ongtowasruk, were mauled to death Jan. 17 in the coastal town of Wales, the westernmost city on the mainland of North America. The pair were leaving a school when a polar bear attacked them in the middle of the street: A heavy snowstorm at the time meant that Myomick did not see the bear coming until it was too late. School staff attempted to stop the bear by hitting it with shovels, but the bear turned on the staff and forced them to retreat back into the school, which was full of pupils at the time. The school remained in lockdown until a village resident arrived with a gun and shot the polar bear dead, AP News reported.

"Polar bear attacks on people are extremely rare," Lindsey Mangipane, a wildlife biologist with the U.S. Fish and Wildlife Service's Polar Bear Program in Alaska, told Live Science in an email. The last U.S. attack happened in 1993, and the last fatality occurred in 1990, in Point Lay, Alaska, she added. 

So what caused the rare attack?

Dr. Kimberlee Beckmen, a vet with the Alaska Department of Fish and Game's Division of Wildlife Conservation (DWC), conducted tests on tissue samples collected from the dead polar bear to learn more about why the animal behaved so aggressively. The results were released Feb. 3 in a statement by the DWC.

Related: Move over polar bears, there's another top predator along the Arctic coast

At the time of the attack, there was speculation in the media that the bear may have had a brain-altering disease, such as rabies, toxoplasmosis, distemper or bird flu. "These conditions could impact bear behavior," Mangipane said, "but because we don't generally encounter affected bears in [the] wild, we are unsure how symptoms would impact the way bears interact with people."

However, the tests carried out by Beckmen came back negative for any brain-altering pathogens. Instead, the bear's sex and physical condition were likely to be the "key factors" that influenced the attack, Mangipane said.

The bear in the Wales attack was an adult male in "poor body condition" and was likely elderly, according to DWC. (A tooth was sent for a separate analysis to determine the bear's age, but the results haven't been released at the time of publication.)

In a 2017 study, published in the journal Wildlife Society Bulletin, researchers analyzed data from 73 polar bear attacks between 1870 and 2014 across Canada, Greenland, Norway, Russia and the U.S. and found that "nutritionally stressed adult male polar bears were the most likely to pose threats to human safety." This latest attack is consistent with these findings, Mangipane said.

There was "no definitive explanation as to why the bear was in poor body condition," DWC representatives wrote in the statement. But it is possible that human-caused climate change played a role. 

"Sea ice loss is resulting in polar bears having less access to their primary prey," such as seals, Mangipane said. "This means that polar bears may increasingly be in poor body condition, especially when encountered on land." 

Climate change could also be elevating the risk of attacks occurring in other places.

"Historically, polar bears spent most of their time on the sea ice which resulted in minimal spatial overlap with people," Mangipane said. "As the open-water season becomes longer [due to increased melting], some areas are experiencing more bears on land for longer periods of time, increasing the probability of human-bear interactions."

In coastal ecosystems around the Arctic peninsula, polar bears have long been considered the top predators. But a new study suggests that sea stars could be surprising contenders to rival the famous white bears at the summit of the local food web.

A food web is a sprawling map of ecological connections that combines all the different food chains within an ecosystem. Individual food chains contain primary producers, which derive energy from the sun or by recycling dead organic material; primary consumers that graze upon the primary consumers; and then secondary or tertiary consumers that prey upon all the consumers beneath them. But the organisms in one food chain can also have a place in another, or multiple others, so the best way to see how an ecosystem functions is to link these chains together.

In marine food webs, researchers often focus on pelagic, or open water, food chains that contain tiny, surface-dwelling plankton all the way up to large predators such as polar bears (Ursus maritimus), which often sit at the top of multiple food chains. But the seafloor, or benthic, realm is often overlooked in marine food webs because scientists believed it has no real top predators of its own. 

But in a new study, published Dec. 27, 2022, in the journal Ecology, researchers took a more in-depth look at a coastal marine ecosystem in the Canadian Arctic and found that the benthic component of the region’s food web had been majorly underappreciated. The research team created a detailed map of the various food chains surrounding Southampton Island, in the mouth of Hudson Bay in Canada's Nunavut territory, and found that the benthic part of the web had just as many connections as its pelagic counterpart, as well as its own equivalent of the polar bear — predatory sea stars.

Related: Swarm of rainbow-colored starfish devour sea lion corpse on seafloor 

"It’s a shift in our view of how the coastal Arctic marine food web works," study lead author Rémi Amiraux, a marine ecologist at Laval University in Canada who was with the University of Manitoba when the study was conducted, said in a statement. "We proved that the wildlife inhabiting the seawater and those inhabiting the sediment form two distinct but interconnected subwebs."

The researchers analyzed data on 1,580 individual animals living in the Southampton Island coastal ecosystem to create the new food web. They found that the benthic and pelagic components each had a similar number of steps, or trophic levels, in their respective food chains. 

Sea stars were a key part of the benthic food web, occupying various trophic levels, but one family,  Pterasteridae, was consistently at the top of most individual food chains. The researchers discovered that these sea stars feed on a range of secondary consumers including bivalves, a group of mollusks whose bodies are protected by a hinged shell, sea cucumbers and sponges. This means Pterastidae sea stars were hunting on an equivalent scale to polar bears, which preyed upon walruses, gulls, beluga whales (Delphinapterus leucas) and ringed seals (Pusa hispida). The key difference between the polar bears and sea stars was the size of their prey. 

In addition to being among the most successful predators in the entire ecosystem, the Pterasteridae sea stars and polar bears also shared the ability and willingness to scavenge, which researchers believe has enabled both groups to thrive in the Arctic. 

The sea stars opportunistically fed on dead pelagic organisms that sank to the seafloor, meaning they had to hunt less often. Similarly, polar bears can scavenge on whales that wash up dead, which can sustain them for weeks or even months, researchers wrote in the study.

The team believes that the new findings highlight the importance of seafloor food chains in many other marine food webs. Pterasteridae sea stars are found in almost all marine ecosystems, and if they are as successful elsewhere as they are in the Arctic, they could turn out to be one of the ocean's most successful predators, researchers wrote.

As climate change diminishes Arctic sea ice, polar bears (Ursus maritimus) are being forced to ransack towns and garbage dumps in ever greater numbers, a new study in the journal Oryx finds. 

While bears eating human garbage is not a new phenomenon, the frequency and severity of human-bear interactions in the Arctic are increasing steadily, the study authors wrote, with some encounters ending in polar bears being shot and killed.

"What we have seen is an increase in intensity (of encounters) and increased occurrences in places where polar bears don't normally occur," study co-author Geoff York, a researcher with Polar Bears International, told The Globe and Mail.

In the new study, the researchers described six case studies that showed above-average (and occasionally deadly) polar bear encounters with Arctic communities in the United States, Canada and Russia. In each town or community, the number of polar bear sightings has increased steadily over the past several years or decades, leading to some dicey situations.

In 2019 in Russia, for example, ravenous bears overran garbage dumps in two Arctic villages. The town of Belushya Guba (population roughly 2,000) reported a "mass invasion" of 52 polar bears beginning near the town's open landfill, with some of the bears later venturing further into town and attempting to access buildings. Meanwhile, in the village of Ryrkaypiy (population 600), 60 polar bears took over the town's garbage dump for several weeks. 

In Arctic Canada, two polar bears were shot and killed — one in 2015 and one in 2016 — after venturing too close to human settlements, the study added.

It's likely that human-made climate change is at least partially responsible for the increase in human-polar bear interactions, the study authors wrote. 

All six case study communities are located near coasts where sea ice forms in late autumn, which gives polar bears a platform from which to hunt prey like seals and walruses, according to the study. As warming temperatures diminish the available sea ice each year, bears may be forced to venture inland and seek alternate food sources from towns and landfills, the researchers wrote.

It doesn't matter that the nutritional value of human garbage is less than ideal — or that dumpster-diving bears may be ingesting everything from batteries to dirty diapers to ceramic containers coated with food, York told The Globe and Mail.

"Polar bears will come a long distance if they can smell food," York said. "If they can find a reliable source of calories, they will go to extraordinary measures to come back."

One solution to the problem is to replace open landfills with composters or incinerators to dispose of organic waste, thereby minimizing opportunities for polar bears to come into contact with humans, York added. However, even with landfills closed, polar bears will likely continue venturing into Arctic towns in search of food so long as sea ice diminishes. This challenge is just one more unforeseen consequence of climate change, and underscores the importance of taking meaningful global action.

Originally published on Live Science.

A secret population of polar bears in Greenland has been discovered in a seemingly impossible habitat — one that, for most of the year, lacks the floating platforms of sea ice the beasts use to hunt. The unusual group, which scientists previously thought was part of another nearby population, has been hiding in plain sight for hundreds of years.

The bears live on the steep slopes around fjords — long and narrow coastal inlets, where glaciers meet the ocean — and hunt on a patchwork of glacial ice that breaks up in these inlets. The new discovery suggests that some polar bears, at least, may be able to adapt to sea ice disappearing as climate change worsens, the study suggests.

Still, that's no silver bullet for the species at large.

"Glacier ice may help small numbers of polar bears survive for longer periods under climate warming, but it is not available for the vast majority of polar bears," lead researcher Kristin Laidre, a wildlife scientist at Polar Science Center at the University of Washington, told Live Science in an email. That's because this type of glacier ice is only found near a small fraction of other polar bear populations.

Related: Why aren't there polar bears in Antarctica?

Until recently, scientists had identified 19 known subpopulations of polar bears (Ursus maritimus) living in the Arctic Circle. One of those populations spans a 1,988-mile (3,200 kilometers) stretch of the eastern coast of Greenland. But when researchers took a detailed look at this group to monitor their numbers, they realized the bears actually comprised two completely separate populations. 

Researchers analyzed 36 years' worth of tracking data from bears tagged with GPS collars and found that bears from southeast Greenland did not pass above a latitude of 64 degrees north, and bears from the northeast did not pass the same line in the other direction. Genetic sampling from individual bears confirmed that the southeastern bears were distinct from their northeastern neighbors. 

"We present the first evidence for a genetically distinct and functionally isolated group of polar bears in southeast Greenland, which meet [the] criteria for recognition as the world’s 20th polar bear subpopulation," the researchers wrote in their new study, which was published June 16 in the journal Science.

The new southeastern population contains around 300 individuals, although determining an exact number is tricky, the researchers said. The newfound group is the most genetically diverse out of all 20 populations in the Arctic, and genetic comparisons suggest that they have been isolated from the northeastern population for around 200 years, the researchers said.

Polar bears are listed as vulnerable to extinction, according to the International Union for Conservation of Nature (IUCN) Red List, and there are around 36,000 individuals left in the wild. But some studies have suggested that the species could vanish by the end of the century due to the effects of climate change.

Despite being the world's largest land predator, polar bears are actually listed as marine mammals because they rely on a predominantly aquatic diet, consisting mainly of seals. But in order to hunt for food, the snow-white bears rely on sea ice as a platform to stalk their prey from above. Unfortunately, rising temperatures caused by climate change are reducing the amount of sea ice available, shrinking their natural habitat.  

Sea-ice extent waxes and wanes in the Arctic. The temporary ice sheets form on the ocean's surface during autumn and then melt away in spring. Polar bears normally survive for between 100 and 180 days without food as the sea ice disappears over the summer. But warming temperatures in the Arctic mean that sea ice is melting sooner and freezing later, pushing polar bears to the brink of starvation.

The fjords that are home to the southeastern polar bears lie at the southern edge of the Arctic Circle and, as a result, the region is sea ice-free for more than 250 days a year. These sea ice conditions mimic those predicted for the rest of the Arctic by the end of the 21st century, based on previous studies, which should make the fjords unlivable for polar bears, the researchers said. But the southeastern bears seem to be managing surprisingly well without the sea ice.  

The researchers think that the bears are taking advantage of glacial mélange, or the bits of ice that break off the fjords' glaciers and into the sea. The bears likely use these freshwater ice patches in the same way they use sea ice to hunt, which allows them to feed themselves during the long spells when sea ice is absent from the region. "This suggests that marine-terminating glaciers may serve as previously unrecognized climate refugia," the researchers wrote.

The southeastern population also lives nowhere near any human populations, and the area is believed to be too hard to reach for most hunters, which adds an extra layer of security for the bears. However, the steep slopes of the fjords can also be quite tricky for the polar bears to traverse, which may limit their movements. The birth rate among the new population is also very low compared with other populations, which researchers suspect is because potential mates struggle to reach one another.

In the new study, the researchers used genetic data to identify two individuals that could be immigrants from the northeastern population. These immigrant bears appear to have adapted very well to hunting on glacial mélange, which suggests that other populations might be able to follow suit as sea ice conditions deteriorate in other areas. The researchers identified other similar locations where glacial conditions could support polar bears in northern Greenland and Svalbard. However, moving to these locations may not be possible for a majority of bears. 

Although the study does provide a glimmer of hope for some polar bears, the researchers insist that this does not make climate change any less of a threat to the Arctic predators. "Loss of Arctic sea ice is still the primary threat to all polar bears," Laidre said. "This study does not change that." Sea ice will continue to decline across the Arctic, which will decrease the survival odds for most polar bears, she added.

Originally published on Live Science.

Spanish police have seized more than 1,000 taxidermy animals that were part of a private collection worth around $32 million in what they have described as "one of the largest ever" illegal wildlife busts in Europe. Almost half of the specimens recovered are either listed as endangered or have already been declared extinct.

Officers from Spain's Civil Guard seized the collection o from a massive warehouse in the town of Bétera near Valencia in Eastern Spain, according to a statement released on April 10. 

In total, officials recovered 1,090 taxidermy specimens, including entire elephants, white rhinos, cheetahs, leopards, lions, crocodiles, tigers and a polar bear, as well as 198 elephant tusks. The team also found other items, including stools that appeared to be made from elephants' feet and chairs upholstered with crocodile skin, according to a video by ABC News. 

Related: Man caught at Mexican border allegedly had more than 50 reptiles stuffed into his clothing

The officials said 405 of the specimens belong to species that are illegal to trade internationally under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The collection also included a scimitar oryx, which was declared extinct in 2000, and an addax, a type of antelope that is functionally extinct in the wild, which means there as so few left that it is almost a certainty they will eventually disappear.  

The collection is estimated to be worth around $31.6 million (29 million euros) on the black market, according to the statement. 

The interior of the warehouse, which is around 538,000 square feet (50,000 square meters), looks like a natural history museum in images; some of the walls are painted with vistas from some of the animals' natural habitats, and some specimens were housed in glass display cases. The warehouse also contained basic living quarters and two boats, according to the statement.

The owner of the property has been the target of a major international investigation since November 2021 but has not been arrested. However, he continues to be investigated for wildlife smuggling, according to the statement. 

Originally published on Live Science.

Grizzly bears are a type of brown bear that live in North America. The name "grizzly bear" is typically given to members of the subspecies Ursus arctos horribilis, but the scientific classification of American brown bears is not settled, and some people use "grizzly bear" and "brown bear" interchangeably. 

Grizzly bears are named after their grizzled hair, which can be streaked with strands of gray or silver. However, people commonly believe the word "grizzly" comes from "grisly," which means to cause horror, according to the Center for Biological Diversity. Despite their imposing size and appearance, grizzly bears rarely attack humans. 

Are grizzly bears and brown bears the same?

Brown bears (Ursus arctos) are the most widely distributed bears in the world and can be found in North America, Europe and northern Asia, according to the International Union for Conservation of Nature (IUCN). North America's brown bears are split into two main groups; grizzly bears and Kodiak bears (Ursus arctos middendorffi). While Kodiak bears are only found on the Kodiak Archipelago in Alaska, grizzly bears live across the rest of their North American range, according to the National Wildlife Federation (NWF). This includes mainland Alaska, three other U.S. states and Canada. 

Grizzly bears can be grouped together under the subspecies Ursus arctos horribilis, but some sources recognize multiple subspecies. For example, the Integrated Taxonomic Information System (ITIS) recognizes eight brown bear subspecies in North America, including extinct California grizzly bears (Ursus arctos californicus). These grizzlies inhabited California until humans wiped them out in the 1920s, according to the Pacific Grove Museum of Natural History in California. 

"Grizzly bear" is a common (rather than a scientific) name, so it doesn’t necessarily correspond to a specific subspecies. According to the NWF, many North Americans use "grizzly bear" to describe smaller and lighter-colored bears that live in interior areas, and "brown bear" for larger and darker bears in coastal areas. Regardless of how the name is used, all grizzly bears are members of the only brown bear species. 

Related: Mountain goat kills grizzly bear by stabbing it with razor-sharp horns

What do grizzly bears look like?

Grizzly bears are typically 3 to 5 feet (0.9 to 1.5 meters) tall at the shoulder when standing on all fours and can reach almost 9 feet (2.7 m) tall when standing on their hind legs. Males are heavier than females and weigh up to 860 pounds (390 kilograms), while females weigh up to 455 pounds (205 kg). Grizzlies are smaller than Kodiak bears and polar bears, which can both stand more than 10 feet (3 m) tall.  

Grizzly bears’ coat color can be anything from blond to black, according to the National Park Service. This wide variation in size and coat color means that these two features alone aren't surefire ways to tell grizzly bears apart from American black bears (Ursus americanus), which are typically smaller and darker — but not always.  

A more reliable method to distinguish grizzly bears from black bears is to look at a bear's body shape and tracks. All brown bears, including grizzly bears, have a pronounced shoulder hump that is higher than their rump. Black bears lack a hump, and their rumps are higher than their shoulders. Furthermore, grizzly bears have dish-shaped faces and short, round ears, while black bears have straight faces and taller, more oval-shaped ears, according to the NPS. Brown bears also have longer and straighter claws that leave marks in tracks more often than black bear claws do. 

Are grizzly bears dangerous?

Grizzly bears typically avoid people unless they perceive them as a threat to their cubs, food or territory. However, bears do sometimes attack and kill humans. Brown bears have killed 84 people in the U.S. and Canada since 1900, according to the Florida Museum of Natural History. The same records show that black bears have killed 78 people and polar bears have killed 11 people during the same period. 

The NPS recommends that people keep their distance from bears, make an effort to be noticeable when in a bear's environment and avoid surprising them. Bear behavior can be unpredictable, and there isn't a strategy to deal with bear attacks that will work in every situation.

According to the NPS, if attacked by a grizzly or brown bear, you should leave your backpack on (if you have one) and play dead by lying flat on your stomach with your hands clasped on the back of your neck and legs spread — this makes it harder for the bear to turn you over. Grizzlies usually attack with greater intensity if you fight back, so it's best to stay still until the bear leaves you alone. However, you should fight back vigorously if the attack persists by striking the bear in the face with anything available to you, according to the NPS. The NPS advice differs for black bear attacks: During a black bear attack, it is never advisable to play dead. Victims of black bear attacks should try to escape or fight back if no escape is possible. 

People who are in a tent when attacked by any bear, or stalked and then attacked, should not play dead and should instead immediately fight back. In this scenario, the bear sees humans as prey, the NPS says. 

Related: Woman killed in unusual grizzly bear attack

Where do grizzly bears live?

The vast majority of North American brown bears, which includes most grizzly bears, live in Alaska. The state is home to an estimated 30,000 brown bears, or about 95% of the total population, according to the Pacific Grove Museum of Natural History. Grizzly bears also live in Canada and the U.S. states of Washington, Idaho, Montana and Wyoming, according to the International Association for Bear Research and Management. 

Grizzly bears are adaptable and occupy different habitats across their range, including coastal areas, mixed-conifer forests, grasslands, mountainous forests and Arctic tundra, according to the Center for Biological Diversity. Individual bears live within home ranges that cover 50 to 150 square miles (130 to 390 square kilometers) for females and up to 600 square miles (1,555 square km) for males, and their ranges can overlap with other bears’ territories, according to the University of Montana's Grizzly Bear Recovery Program. 

Grizzlies are solitary but do sometimes interact with other bears. When grizzly bears rub trees with their backs, they're not trying to scratch an unbearable itch. Rather, they are communicating with one another by leaving their scent. They also use urine to mark their territory, and they communicate with other bears using sounds and movement, according to the Pacific Grove Museum of Natural History.

Grizzlies can be diurnal (active during the day) or nocturnal (active during the night), and they may switch their activity patterns if disturbed by humans. A 2013 study of bears in Yellowstone National Park, published in the Journal of Mammalogy, found that grizzly bears' peak period of activity varied from midday to evening depending on the season, suggesting that they also change their activity patterns based on food availability.  

What do grizzly bears eat?

Grizzlies are omnivores, which means they eat a mixed diet of vegetation and meat. A grizzly bear's diet can consist of fruit, nuts, leaves, roots or animals, which can be as small as insects or as large as ungulates, such as moose. 

The 2013 study of Yellowstone bears found that 70% of the bears’ elk calf kills took place at dusk or night, when the calves were likely easier to catch; the bears were therefore nocturnal during the calving season in late spring and early summer and became diurnal during the summer and early fall, when their diet shifted to roots, berries and nuts. A 2006 study into grizzly bear diet published in the Canadian Journal of Zoology found that grizzly bears eat more meat in areas where ungulates and spawning salmon are more abundant. 

Grizzly bears eat as much food as they can in the summer and fall to build up fat reserves before they enter dens and hibernate over winter. Grizzlies are excellent diggers and use their front claws to dig dens into hillsides, or they make their dens in rock caves, tree hollows or brush piles, according to San Diego Zoo. During hibernation, a grizzly's heart rate slows from 70 beats per minute to only 10 beats per minute;  metabolic activity also decreases, and the bear stops defecating. Hibernation time varies with the length of winter across the grizzlies' range, but they can stay in their dens for up to seven months living off their fat reserves. Captive grizzly bears that have access to food all year round, such as the bears in San Diego Zoo, may not hibernate at all. 

How do grizzly bears reproduce?

Grizzly bear mating season takes place from May to July, according to the University of Michigan's Animal Diversity Web (ADW). During that time, fertilized eggs start to develop in females, but implantation in the uterus is usually delayed until November when the female is hibernating. After a gestation period of six to eight weeks, a mother gives birth to between one and four grizzly bear cubs. Newborn cubs weigh between 12 and 24 ounces (340 and 680 grams) and are cared for by their mother in the den. 

Mothers stay with their cubs for at least two years before separating. Most grizzly bears live for up to 25 years in the wild, according to the NWF. However, some bears may live beyond 30 years. In 2020, a 34-year-old male grizzly bear monitored by scientists was caught in the Yellowstone region — although it was subsequently euthanized as it was in extremely poor physical condition and had begun attacking cattle, the Jackson Hole News & Guide, a newspaper in Wyoming, reported. 

Related: During Fat Bear Week, bears compete in a battle of the bulge

Are grizzly bears endangered?

The IUCN doesn’t consider brown bears to be an endangered species, and they are listed as Least Concern. However, this assessment covers all brown bears around the world and not grizzly bears in North America specifically. 

There were an estimated 50,000 grizzly bears spread across what is now the western U.S. until they were annihilated en masse in the 1800s by settlers, who tried to eradicate the bears. Thousands of grizzlies were shot, poisoned and trapped, and by the 1930s they were restricted to about 2% of their former range, according to the U.S. Fish & Wildlife Service. 

Grizzly bears became protected as a threatened species in the Lower 48 states in 1975, and it is illegal to kill them unless a person is defending themselves or another person. Grizzly bear hunting is legal but regulated in Alaska, where licensed hunters are permitted to kill bears with certain restrictions, such as not being allowed to target bears with cubs, according to the Alaska Department of Fish and Game. Today, it is estimated there are between 20,000 and 26,000 grizzly bears in Canada. There are about 30,000 grizzly bears in Alaska and an estimated 1,900 in the lower 48 states.  

Additional resources

To learn more about where the "grizzly bear" name came from, read parts 1 and 2 of "A Bear by Any Other Name: The Many Monikers of Ursus arctos" on the Alaska Department of Fish and Game website. For more information about bear attacks, check out "Bear Attacks: Their Causes and Avoidance" (Lyons Press, 2018), available to buy at Amazon. To see grizzly bears catching salmon, watch this short YouTube video by BBC Earth.  

Bibliography

Alaska Department of Fish and Game, "Black Bear Hunting in Alaska," 2021. https://www.adfg.alaska.gov/index.cfm%3Fadfg%3Dblackbearhunting.blackbrown

Dewey, T, and Ballenger, L. Animal Diversity Web, "Ursus arctos," 2002. https://animaldiversity.org/accounts/Ursus_arctos/

Center for Biological Diversity, "Grizzly bear." https://www.biologicaldiversity.org/species/mammals/grizzly_bear/natural_history.html

Fortin et al. "Temporal niche switching by grizzly bears but not American black bears in Yellowstone National Park," Journal of Mammalogy, Volume 94, Aug. 16, 2013. https://academic.oup.com/jmammal/article/94/4/833/895215

Florida Museum of Natural History, "International Shark Attack File: Bear Attacks," updated Feb. 11, 2021. https://www.floridamuseum.ufl.edu/shark-attacks/odds/compare-risk/bears/

Grizzly Bear Recovery Program, University of Montana, "Grizzly bear biology." https://www.cfc.umt.edu/grizzlybearrecovery/grizzly-bears/biology.php

Integrated Taxonomic Information System, "Ursus arctos Linnaeus, 1758," reviewed 1993. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=180543

International Association for Bear Research and Management, "Brown bear." https://www.bearbiology.org/bear-species/brown-bear/

McLellan et al. "Ursus arctos," The IUCN Red List of Threatened Species, 2017. https://www.iucnredlist.org/species/41688/121229971

Koshmrl, M., Jackson Hole News & Guide, "Grizzly 168 brushes up against longevity records for North American bears," Jan 20, 2021. https://www.jhnewsandguide.com/news/environmental/grizzly-168-brushes-up-against-longevity-records-for-north-american-bears/article_d1786f9b-cd62-5ef4-ad53-7d0b3efdee5b.html

Mowat, G., and Heard, D. C. "Major components of grizzly bear diet across North America," Canadian Journal of Zoology, Volume 84, March 28, 2006. https://www.researchgate.net/publication/237973703_Major_components_of_grizzly_bear_diet_across_North_America

National Park Service, "Bear Identification," updated Oct. 26, 2021. https://www.nps.gov/articles/bear-identification.htm

National Park Service, "Grizzly Bear," updated Nov. 1, 2021. https://www.nps.gov/yell/learn/nature/grizzlybear.htm 

National Park Service, "Staying Safe Around Bears," updated April 13, 2018. https://www.nps.gov/subjects/bears/safety.htm

National Wildlife Federation, "Grizzly Bear." https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Grizzly-Bear

Pacific Grove Museum of Natural History, "Brown Bears." https://www.pgmuseum.org/brownbear

San Diego Zoo, "Brown Bear," 2022. https://animals.sandiegozoo.org/animals/brown-bear

U.S. Fish & Wildlife Service, "Ursus arctos horribilis," 2021. https://www.fws.gov/species/brown-bear-ursus-arctos-horribilis

This article was originally written by Live Science contributor Alina Bradford and has since been updated.   

Editor's note: The numbers of grizzly bears in the U.S. and Canada was corrected at 3.26 a.m. on May 21, 2024.

The Arctic and Antarctica, while similar habitats in some ways, are home to very different creatures. Both poles host a variety of seal and whale species, but only the Arctic is home to Earth's largest bear, the polar bear.

Polar bears (Ursus maritimus) and their tumbly cubs can be found around the Arctic Circle in Alaska, Canada, Greenland (part of Denmark), Norway, Russia and, occasionally, Iceland. A polar bear's fur is specially suited for temperatures that can dip below minus 22 degrees Fahrenheit (minus 30 degrees Celsius). They live on ice for most of their lives, feeding on fat-rich seals that keep them energized for long periods between meals.

Antarctica also has sea ice, cold temperatures and seals. So why aren't there any polar bears on the southernmost continent?

The answer has to do with evolution and the geologic history of Earth.

Related: How do emperor penguin dads stop their eggs from freezing?

"Bears are largely a Northern Hemisphere phenomenon," said Andrew Derocher, a professor of biological sciences at the University of Alberta in Canada who has studied polar bears for nearly 40 years. Aside from the Andean bear (Tremarctos ornatus) of South America, bears appear only in the Northern Hemisphere. There's no specific reason for this, just that some species evolve in some places and some don't. "Biogeography is full of oddities," Derocher said. "Some species made it to new places and some didn't."

For polar bears specifically, there was never a time in their evolutionary history when the North and South poles were connected by ice (or land, for that matter). People say polar bears are the "biggest terrestrial carnivore in the world, and yet they're not a terrestrial species at all," Derocher told Live Science. The big, white bears live on sea ice for almost their entire lives, only occasionally coming ashore to breed.

Polar bears are, evolutionarily, a relatively young species. They evolved from a common ancestor of the brown bear (Ursus arctos) sometime between 5 million and 500,000 years ago, Derocher said. But even 5 million years ago, the continents were in similar positions to where they are today, so polar bears never got the opportunity to travel from pole to pole. The closest landmass to Antarctica is the southern tip of South America, which includes Chile and Argentina. To get to Antarctica, polar bears would have to cross the treacherous Drake Passage. The area is also known for powerful storms and rough seas as cold water from the south runs into warm water from the north.

But if polar bears got the opportunity, would they survive on the South Pole?

To Derocher, the answer is simple: "They would have so much fun in Antarctica."

In the Arctic, polar bears feed on seals and the occasional bird or egg. Antarctica is abundant in all three, with six seal species and five penguin species. Plus, none of those animals have evolved to be wary of large, land-roving predators. The Antarctic landscape would be a free-for-all buffet for a polar bear — which is why no one should ever bring polar bears there. Their voracious appetite, combined with the local faunas' ignorance of large land predators, would likely lead to ecological collapse. It's probably best for the great white bear to remain in the north.

Originally published on Live Science.

Dozens of polar bears have been making themselves at home in abandoned buildings on an Arctic island, and a Russian photographer recently captured remarkable photos of the bears peering through windows and standing on porches.

When photographer Dmitry Kokh traveled to the remote Russian region of northern Chukotka in late summer 2021, he was hoping to find polar bears to photograph on Wrangel Island, a natural reserve and World Heritage site that's protected by the United Nations Educational Scientific and Cultural Organization and is located above the Arctic Circle. 

What he found instead was a strange and unexpected sight: On the smaller Kolyuchin Island to the south of Wrangel Island, more than 20 polar bears had taken up residence in buildings that were once part of a Soviet weather station. Kokh photographed the polar bears in their dilapidated homes and shared the photos on his website and on Instagram, alongside other examples of his dramatic marine wildlife photography, and the images struck a chord with viewers and quickly went viral, Kokh told Live Science.

Related: Polar bear photos: Stunning shots capture Earth's icons of climate change 

As Kokh sailed 1,200 miles (2,000 kilometers) north to the islands from his starting point at Anadyr, the capital of Chukotka, he noticed that there was far more sea ice than is typical for Chukotka's northern coastline during the summer months. Abundant sea ice could explain why the bears were visiting Kolyuchin Island instead of sticking to their usual summer territories farther north, as polar bears use sea ice for hunting their seal prey, he said. 

Kolyuchin is so small, "you can see almost the whole island from your boat," he said, and while there was once a Russian weather station on the island, it was abandoned in 1991 after the Soviet Union collapsed. Shortly after Kokh's boat docked near Kolyuchin to wait out a storm, "we saw some movement in the window of this weather station — and then we saw that it was a bear," Kokh said. "We saw one, then we saw another one, then 20 of them. And they all were inside this building."

To capture the photos, Kokh used a camera mounted on an aerial drone that had been modified with low-noise propellers, making it quiet enough to slowly approach the bears without disturbing them. In the photos, the bears appear unconcerned about the camera and photographer — but when it comes to polar bears, looks can be deceiving, Kokh warned.

"Polar bears are very clever — and sometimes tricky — hunters," he said. "Sometimes they pretend they are not looking at you, and they are relaxed; at this moment, they are ready to attack." 

A nature reserve employee was with the group at all times, carrying a rifle and flares as precautionary measures to ensure the team's protection. Polar bears weigh up to 1,700 pounds (770 kilograms), but for all that bulk, they are surprisingly quick, capable of galloping up to 24 mph (40 km/h), according to McGill University.

Polar bears usually inhabit remote parts of the Arctic that are far from humans, but climate change is reshaping their habitat and has even driven bears to invade towns in the Russian Arctic in search of food. Since 1979, the sea ice that the bears depend on for hunting has shrunk and grown thinner, and researchers predict that summer sea ice could vanish from the Arctic by the end of the century, Live Science previously reported.

Though polar bears face an uncertain future, these images of the bears peering out from ramshackle buildings are a reminder that life on Earth can persist even as human-made objects and structures break down, Kokh told Live Science.

"But life will exist forever only if we care about it," he added.

Originally published on Live Science.

People have smuggled hundreds of bear body parts — including polar bear parts — into Australia and New Zealand, a new study reveals. 

Enforcement agencies seized bear teeth, rugs, bile and embryos suspended in honey from passengers arriving in Australia and New Zealand from 2007 to 2018.

Most of the bear parts and derivatives, such as gallbladder bile, were ingredients in traditional medicines. The goods were most often seized from people traveling into Australia and New Zealand from China, but they also came from other countries such as the U.S. and Canada. 

"We knew we would find some records, but we never expected them to be in the hundreds or the diversity of products and number of countries from which they were being sourced/transported," lead author Phill Cassey, head of ecology and evolutionary biology at the University of Adelaide in Australia, told Live Science in an email. 

Related: Polar bear photos: Stunning shots capture Earth's icons of climate change 

Trade in wildlife threatens many species around the world, according to World Wildlife Fund (WWF). Bears are traded for their gallbladder bile, which is used in traditional Asian medicines, as well as their meat and body parts, such as those used as hunting trophies, according to the study. 

To gain a greater understanding of the bear trade, the researchers looked at countries that don't have their own wild bears. "We were intrigued to know how much of a role countries without native bears were playing in this trade," Cassey said. 

The research team found records of 781 seizures; 369 in Australia and 412 in New Zealand. They involved five of the eight bear species and all seizures were declared for "personal use." The number of seizures declined in Australia during the study period, from a peak of 74 in 2011 to 12 in 2018. There was no such decline in New Zealand. Though  2009 was a peak for seizures with 52 and 2018 was a low point with 13 seizures, the overall trend was more variable than Australia, with more than 40 seizures in 2017 for example.   

The items seized came from 33 countries spread around the world, with China being the reported origin of 37.7% of seizures in Australia and of 71.2% of seizures made in New Zealand, according to the study. The most common items seized were traditional medicines made out of bear bile, the researchers reported in the study published Nov. 4 in the journal Pacific Conservation Biology. 

Humans obtain bear bile by killing bears or by keeping them alive in cages in bear farms, where handlers regularly extract the bile, such as through a catheter inserted in their gallbladder, according to Animals Asia, a nonprofit working to end bear bile farming. 

Bear bile contains ursodeoxycholic acid, which can be used to reduce the absorption of cholesterol and  dissolve gallbladder stones in people, according to the Chemical Entities of Biological Interest (ChEBI) database. However, herbal and synthetic alternatives exist with the same properties and bear bile is used to treat many conditions that it does not benefit, such as hangovers, according to Animals Asia. 

The U.S. and Canada were the biggest source of bear body parts, such as teeth, claws and trophy heads. "North America is popular with trophy hunters," Cassey said. "Some legal hunting is still permitted in North America and Europe, and clearly Australians and New Zealanders are partaking in these activities." 

Travelers had legally procured some of these seized items, which were returned to them. That was the case far more often for trophies than it was for medicines, teeth and claws, the majority of which were illegal. The study highlights the demand for bear parts and their derivatives in countries without wild bears.

"The illegal wildlife trade is a global problem, which needs global solutions," Cassey said. "Just because Australia and New Zealand don't have any native bears doesn't mean they aren't part of the problem.

Originally published on Live Science.

Picture a polar bear stalking an unsuspecting walrus in the frozen Arctic: The predator slowly inches closer, camouflaged by ice and snow, until it's close enough to pounce. And then it delivers the killing blow — by bopping the walrus on the head with a large rock.

That might sound like something you'd see in a cartoon, rather than in nature. But for centuries, Inuit people in the Arctic have shared such stories with non-Native explorers and naturalists, describing polar bears killing or stunning prey with stones and chunks of ice that the bears grasp in their paws (or throw off cliffs onto animals at the bottom, according to a memorable 19th-century engraving).

A new study looked at Inuit anecdotes describing this behavior — "from a diversity of locations and over a long period of time" — and found they were so widespread and consistent that they suggested that in rare cases, polar bears likely wield such objects as weapons. However, until scientific researchers actually catch the Arctic bears in the act of bludgeoning walruses, it's hard to say for sure.

Related: Polar bear photos: Stunning shots capture Earth's icons of climate change

"I have always been impressed with the accuracy and reliability of the observations of animals reported by experienced Inuit hunters, so I thought it was likely the accounts might not just be myths but the result of reporting of actual observations, even though the behavior itself is likely quite rare," study lead author Ian Stirling, a member of the Scientific Advisory Council for Polar Bears International and an adjunct professor in the Department of Biological Sciences at the University of Alberta, told Live Science in an email.

Inuit descriptions of polar bears (Ursus maritimus) hoisting — and sometimes hurling — hefty blocks of rock or ice date to the late 1700s, according to the study. In a description that naturalist Otto Fabricius wrote in 1780 in the book "Fauna Groenlandica," polar bears grab sizable ice chunks and launch them at walruses' heads.

"The bear makes it [the walrus] lose its balance (or 'stagger' is more literal) and thus kills it easily," the scientists wrote in the June issue of the journal Arctic.

An Inuit account from 1883 described another ice-chucking bear that "seized a mass of ice in his paws, reared himself on his hind legs, and threw the ice with great force on the head of a half-grown walrus." A 1925 record of another Inuit report noted that a polar bear "carefully selected a young walrus and threw the ice block down upon it with such a force that it became immobilized," the study authors wrote.

In one astonishing example, illustrated by the 19th-century Arctic explorer Charles Francis Hall, a polar bear allegedly threw a boulder onto a walrus's head from atop a tall cliff. Hall published an engraving of the scene in 1865, basing it on a description by his Inuk guide from Baffin Island.

"The bear mounts the cliff, and throws down upon the animal's head a large rock, calculating the distance and the curve with astonishing accuracy, and thus crushing the thick bullet-proof skull," Hall wrote in the book "Arctic researches, and life among the Esquimaux" (Harper & Brothers, 1865).

"If the walrus is not instantly killed — simply stunned — the bear rushes down to the walrus, seizes the rock, and hammers away at the head till the skull is broken," Hall concluded, according to the study. 

Tools in captivity

The scientists also reviewed more recent reports, by Inuit and non-Inuit witnesses, that suggested the bears used rocks and ice for hunting and for disabling human hunters' traps. But these conclusions were based on the placement of rocks and ice that the bears had left behind and did not reflect observations of the bears actually using the objects as tools, the scientists wrote.

However, in 2010, photos showed a captive male polar bear named GoGo at the Tennoji Zoological Gardens in Osaka, Japan, using "tools" in his enclosure to reach a piece of food. Caregivers had hung a piece of meat about 10 feet (3 meters) above GoGo's pool — too high for him to grab — "to provide stimulation and distract his attention" by challenging GoGo with solving this puzzle, according to the study. 

At first, GoGo tried jumping at the meat. But after a month of failure, he "invented" two tools: a piece of plastic pipe that he chucked at the food, and a branch measuring around 7 feet (2 m) that he used to smack the meat and knock it off its hook. Initially, GoGo took several hours to succeed, but he was soon able to knock down the meat in just 5 minutes, the researchers reported.

GoGo's example, together with centuries of anecdotes and other recent observations, hints that tool use for hunting among wild polar bears — though likely not a common occurrence — is certainly possible, according to the study. 

"An occasional adult polar bear might be capable of mentally conceptualizing a similar use of a piece of ice or a stone as a tool," the study authors reported. However, such extreme measures are probably used only for the biggest prey that polar bears hunt: walruses.

Polar bears prey on walruses and seals, but walruses are much more formidable targets. While an adult ringed seal (Pusa hispida) may weigh up to 165 pounds (75 kilograms), a 2-year-old walrus (Odobenus rosmarus) can weigh a whopping 750 pounds (340 kg) and full-grown adults may weigh as much as 2,000 pounds (907 kg), according to the Alaska Department of Fish and Game. What's more, walruses have long tusks to defend themselves during melee encounters, and their skulls are denser and harder to crack than seal skulls, Erica Hill, a professor of anthropology at the University of Alaska Southeast, reported in 2017 in the journal Études/Inuit/Studies. (Hill was not involved in the recent study.)

The targets of occasional boulder hurling by adult polar bears are therefore most likely to be walruses, the researchers concluded.

Originally published on Live Science.

Endangered polar bears are breeding with grizzly bears, creating hybrid “pizzly” bears, and it's being driven by climate change, scientists say. 

As the world warms and Arctic sea ice thins, starving polar bears are being driven ever further south, where they meet grizzlies, whose ranges are expanding northwards. And with that growing contact between the two species comes more mating, and therefore increased sightings of their hybrid offspring.

With features that could give them an edge in warming northern habitats, some scientists speculate that the pizzlies, or "grolars", could be here to stay.

Related: Polar bear photos: Stunning shots capture Earth's icons of climate change

"Usually hybrids aren't better suited to their environments than their parents, but there is a possibility that these hybrids might be able to forage for a broader range of food sources," Larisa DeSantis, a paleontologist and associate professor of biological sciences at Vanderbilt University in Tennessee, told Live Science. Polar bears have longer skulls, which makes them experts at grabbing seals out of the sea, DeSantis said. "But their molars are smaller than is typical for their body size because all they eat is blubber all day. Grizzlies, on the other hand, can eat whatever they want. We don't know yet, but perhaps the intermediate skull of the pizzly could confer a biomechanical advantage."

Grizzly bears and polar bears only diverged 500,000 to 600,000 years ago, so the two species can mate and produce viable offspring. Observations made in captivity and a study conducted in the wild also suggest that the hybrids are fertile and have themselves produced young.

Wild sightings of hybrid pizzly bears began in 2006, when a hunter shot what he thought was a polar bear in the Northwest Territories of the Canadian Arctic. 

When he took a closer look he found an altogether more unusual animal: A bear with the cream-white fur of a polar bear but the long claws, humped back, shallow face and brown patches of a grizzly. DNA tests confirmed that the animal was a hybrid — the first documented wild offspring of a polar bear and a grizzly bear.

Since then, sightings of the hybrids have been increasing, with a 2017 study in the journal Arctic showing eight hybrids springing from a single female polar bear who mated with two grizzly bears.

The rise of the pizzlies coincides with polar bears’ decline: their numbers are projected to decrease by more than 30% in the next 30 years, according to a 2016 study in the journal Biology Letters. This precipitous fall is linked partly to the encroachment of grizzly bears into polar bear ranges, where they outcompete them for alternative food sources, but also to polar bears' highly specialised diets, as DeSantis highlights in research published on April 1 in the journal Global Change Biology.

According to DeSantis, generalist animals such as coyotes and cougars are the best survivors of rapid change to their environment, not highly specialized apex predators like polar bears and saber-toothed cats. 

"Polar bears consumed soft foods even during the Medieval Warm Period, a previous period of rapid warming. Their diets haven't changed much at all." DeSantis said, referring to blubbery meals such as seals. "It's why what we're seeing now — all of these starving polar bears trying to find alternative food sources — could really represent a tipping point."

According to a statement from the National Snow and Ice Data Center (NSIDC), Arctic sea ice, which the bears use as their hunting grounds, decreased by about 336,000 square miles (870,000 square kilometres) this year from its 1981 to 2010 average maximum. That represents the loss of an area about twice the size of California. Although polar bears can adapt their diet to include sea bird eggs and caribou when on land, a 2015 study published in the journal Frontiers in Ecology and the Environment found that the calories they gain from these sources do not balance out those they burn from foraging for them, Live Science previously reported.

All of this could result in a habitat ready for the hybrids to move in and take over, leading to a loss in biodiversity if polar bears are replaced. 

"We're having massive impacts with climate change on loads of species right now," DeSantis said. "The polar bear is the canary in the coalmine telling us how bad things are."

In some sense, pizzly bears could be a sad but necessary compromise given current warming trends, DeSantis said.

"Apex predators help stabilize ecosystems, and looking forward I really hope the Arctic still has a polar bear. But, with that all being said, could the pizzly allow for bears to continue to exist in intermediate regions of the Arctic? Possibly, yes. That's why we need to continue to study them." 

 Originally published on Live Science. 

The Trump administration announced today (Aug. 17) that it plans to open up part of Alaska's Arctic National Wildlife Refuge (ANWR), a 19 million acre (7.7 million hectares) refuge about the size of South Carolina, to oil and gas leasing — a move that paves the way for drilling in the region, according to news reports.

ANWR has long been a battleground between environmentalists and industry. In 1960, the U.S. government began setting aside land for ANWR, "the only conservation system unit that protects, in an undisturbed condition, a complete spectrum of the Arctic ecosystems in North America," according to a 1987 report. 

However, while ANWR is home to Arctic animals such as polar bears, caribou, fish and 135 species of migratory birds, it's also rich in oil and gas. In particular, the so-called 1002 Area, a 1.5-million-acre (607,000 hectares) zone located along the refuge's Arctic Ocean coastline, is thought to hold about 10.4 billion barrels of technically recoverable oil, according to a 1998 report by the U.S. Geological Survey. This makes it the largest onshore oil reserve in North America, The New York Times reported. 

Related: Why is there so much oil in the Arctic?

U.S. Secretary of the Interior David Bernhardt made the announcement today, saying that the government will likely begin leasing parts of ANWR to oil and gas companies within months, according to Arctic Today. "There certainly could be a lease sale by the end of the year," Bernhardt told reporters during a news conference, as reported by Arctic Today, adding that he would "move forward expeditiously."

Bernhardt said the decision was based on the Republican-passed tax bill in 2017, which mandated that the federal government approve at least two leases of 400,000 acres (162,000 hectares) each by the end of 2024, according to the legislation. In December 2018, the Interior's Bureau of Land Management permitted that drilling could be conducted in the 1002 without harming wildlife, USA Today reported.

Alaskan Gov. Mike Dunleavy (R) and the state's congressional leaders lauded the decision, saying that it would create jobs and help Alaska's economy, Arctic Today reported. That includes potential money for the Inupiat, a group of Alaska Natives who live in Kaktovik, a village of 5,000 to 7,000 people located within the refuge, who often use money from oil revenues to pay for necessities such as schools, infrastructure and health services, Alaska Rep. Don Young (R) wrote in The Hill.

"This is a capstone moment in our decades-long push to allow for the responsible development of a small part of Alaska's 1002 Area," U.S. Sen. Lisa Murkowski (R) said in a statement issued today. 

"I thank all Alaskans who have worked for more than 40 years for responsible resource development in the 1002 Area of ANWR," U.S. Sen. Dan Sullivan (R) said in the same statement. "I particularly applaud the tireless advocacy of the many Alaska Natives — who call the area home — and who know firsthand how responsible oil production can provide enormous economic and social benefits while having minimal impact on the environment."

Environmental responses

However, oil and gas extraction can harm the environment, studies show. For instance, as the Exxon Valdez oil spill demonstrated, oil spills can coat the feathers and fur of animals, disrupting their ability to repel water and stay warm, which increases the creature's risk of hypothermia. Oil can also be poisonous if ingested, and it's challenging to clean up, Natalie Boelman, an Earth scientist at Columbia University's Lamont-Doherty Earth Observatory in New York, who has done research in ANWR, told State of the Planet, a blog of Columbia's Earth Institute. 

Moreover, companies searching for oil can disrupt the land, driving tractors that rip up vegetation and destroy permafrost, which releases the potent greenhouse gas methane, Boelman noted. Industry can also bring increased traffic, construction and, as a result, noise and dust, that can harm the area. People who drill for oil have no way of detecting and avoiding polar bear dens, so these mammals and their young are also put at risk, The Washington Post reported. 

In the past, Democrats have worked to preserve ANWR lands. A congressional deal nearly made it through in 1989, but the Exxon Valdez oil spill upended its momentum, according to The Atlantic. In 1995, then-President Bill Clinton vetoed a budget bill that would have opened the refuge to oil drilling, according to the Oil & Gas Journal. Then, in 2005, the Republican-led Senate tried to open ANWR to drilling, but that movement was stopped by a Democratic filibuster.

In response to today's announcement, environmentalists were quick to say that oil and gas drilling would harm the Arctic's wildlife and ecosystem, and that the move made no sense given today's low oil prices. "Our climate is in crisis, oil prices have cratered, and major banks are pulling out of Arctic financing right and left," Adam Kolton, executive director at Alaska Wilderness League, said in a statement, in reference to Goldman Sachs' December 2019 decision to become the first large U.S. bank to put explicit restrictions on financing for the oil-and-gas industries, especially when it came to protecting ANWR. What's more, Morgan Stanley, Wells Fargo, JP Morgan Chase and Citigroup said they would not finance oil drilling in the 1002 Area. 

"And yet the Trump administration continues its race to liquidate our nation's last great wilderness, putting at risk the Indigenous peoples and iconic wildlife that depend on it," Kolton said.

Related: The Alaskan Arctic oil drilling controversy explained (infographic)

However, during the press call, Bernhardt said that potential investors weren't concerned about the region's short-term prospects, but were focused on its long-term potential, according to Arctic Today.

It remains to be seen how the oil and gas industry will affect wildlife in the 1002 Area, which is designated as critical habitat for polar bears under the Endangered Species Act, according to the 1987 report. That report also called the 1002 area "the most biologically productive part of the Arctic Refuge for wildlife," including caribou, musk oxen, wolverines, Arctic foxes, lemmings, gyrfalcons, ptarmigans and marine mammals. Surveys show that the 1002 Area is home to 700 kinds of plants, 47 species of mammals and 42 species of fish, according to the Wildlife Conservation Society.

Originally published on Live Science.

It's International Polar Bear Day! To celebrate the wonders of the largest of the bear species, one that has become an icon of global warming and polar ice melt, here are some stunning photos that reveal just how magnificent these creatures are.

Big bears

Male polar bears can reach 8 to 11 feet (2.4 to 3.4 meters) from nose to tail and weigh up to a whopping 1,700 pounds (771 kilograms), according to the Center for Biological Diversity. 

Arctic cubs

Polar bears live across the Arctic. They are found in Alaska, Canada, Greenland, Russia and Norway. Alaska polar bears live along the Bering, Chukchi and Beaufort seas.

Following the trail

Between April and late June, male polar bears find mates by following scent trails left on the sea ice by females' foot pads. Even though the actual mating happens at this time, the eggs don't implant until the following fall, according to Polar Bears International. Polar bear cubs tend to be born in December, when the mama bear gives birth to one, two or three cubs, though twins are the most common. 

Sweet cubs

Infant polar bears are just 12 to 14 inches (30 to 35 centimeters) and weigh just a pound (half a kilogram). The little ones are blind, toothless furballs at birth.

A mother polar bear will stay in the den with her cubs until March or early April. During those months, she doesn't eat and focuses all of her energy on feeding her cubs. The newborns grow quickly while feeding on their mom's milk, which is 31% fat, according to Polar Bears International. 

Shown here, a polar bear named Gerda and a cub playing at Novosibirsk Zoo in Russia. 

Leaving the den

These polar bear families leave the den in the spring, as soon as the cubs are strong enough to survive in the harsh Arctic environment. There, the mother can teach them survival skills, such as how to hunt, swim and feed. The cubs can stay with their mother for up to about 3 years.

Built for the cold

Polar bears are built to withstand the bone-chilling temperatures in the Arctic. For instance, their bodies are covered in a dense layer of underfur that's topped with so-called guard hairs, which are longer and coarser than the underfur, according to Polar Bears International. That layering system keeps them from losing any body heat. And even though their fur looks snow-white, it's actually clear (and their skin is a black hue): It just takes on a white appearance because of its structure. Each hair is like a hollow tube, and when sunlight hits each tube it gets scattered in such a way that the fur looks white, according to a report in The Washington Post. 

Top predators

Polar bears are extreme carnivores, feeding mainly on ringed seals, which are chockfull of fat. Apparently the bear's stomach can hold about 15-20% of its body weight, according to the World Wildlife Fund (WWF). And its digestive system, according to the WWF, can absorb about 84% of the protein and 97% of the fat it eats.

Life on ice

Sea ice is a polar bear's life blood in some sense, as they need it for hunting (that's how they catch ringed seals), finding mates and traveling. 

The long hunt

Polar bears are masters of the hunt. And they're patient: Sometimes, they will stay completely still by a seal breathing hole, where they will wait like that for hours or even days, according to the World Wildlife Fund. However, since seals are slippery and designed to escape such a predator, polar bears catch only about 10% or so of what they go after in this way, the WWF explained.

Losing footing

The sea ice that polar bears depend on is vanishing. And while sea ice cover does grow and shrink with the seasons, the cover has been diminishing during both winter and summer months, scientists have found. For instance, in 2019, Arctic sea ice hit its maximum extent on March 13, when it extended some 6 million square miles (15 million square kilometers), which was lower than most of the 40 previous years, according to the National Snow and Ice Data Center (NSIDC).

Where's the ice?

In 2019, the Arctic sea ice cover hit its lowest extent on Sept 18, when it spanned about 1.6 million square miles (4 million square km); that cover tied with 2007 and 2016 as the second lowest since the 1970s, according to NASA. 

Bath time

Turns out, polar bears like to keep their fur clean. And they're not trying to impress a potential mate, but rather clean fur is more efficient at insulating their bodies. When their fur gets dirty and matted, it loses its insulating properties, according to the World Wildlife Fund. 

And so, to keep clean, polar bears take baths. Typically after they feed, a polar bear will wash off by taking a swim or rolling in the snow. 

Swim champs

And when polar bears hop into the ocean to take a bath, they know what they're doing. They are agile swimmers, able to sustain a speed of 6 mph (9.7 km/h) by using their front paws (which are somewhat webbed) to paddle and holding their back legs flat as if a rudder, the WWF noted. Since they spend most of their lives on the ice covering the Arctic Ocean, polar bears are categorized as marine mammals. 

 Polar bears are considered talented swimmers and can sustain a pace of six miles per hour by paddling with their front paws and holding their hind legs flat like a rudder. Their paws are slightly webbed to help them swim. Polar bears are actually classified as marine mammals because they spend most of their lives on the sea ice of the Arctic Ocean.

Originally published on Live Science. 

Fifty-two hungry polar bears have occupied Guba, a work settlement in a remote Russian Arctic archipelago. The animals reportedly attacked locals, ransacked garbage dumps and barged into residential buildings, according to a government statement translated from Russian and released this weekend.

The massive invasion of polar bears prompted regional officials to declare a state of emergency on Saturday (Feb. 9).

"People are scared, afraid to leave the house … afraid to let their children go to school," Zhigansha Musin, a local school administrator, said in the statement. "Constantly in the village are from six to 10 polar bears."

Belushya Guba is a settlement of about 2,000 people in Russia's remote Novaya Zemlya archipelago, which is best known for its spooky plankton blooms and apocalyptic nuclear bomb tests. It's not uncommon to see polar bears near the area's southern coasts, where they regularly converge in winter for seasonal seal hunts, according to Russia's state-run news site TASS. [The Frozen North: Stunning Images of Russia from Above]

However, thinning sea ice caused by global warming likely drove the bears inland in search of more readily available meals, researchers from Moscow's A.N. Severtsov Institute of Ecology and Evolution, a branch of the Russian Academy of Sciences, told TASS. The allure of edible waste in Belushya Guba's garbage bins and dump sites likely stopped the bears from migrating farther north, the researchers said.

But dumpster diving isn't all the beasts are doing. Photos and videos posted over the weekend show the bears traipsing through empty schoolyards and even infiltrating the corridors of office buildings in search of food.

To protect the town, locals have built extra fences around schools and other sites, while special patrols try to scare off the bears with cars and dogs. These measures have shown "no tangible results" in spooking the bears and a special task force of "experts" is en route to assess the worrisome situation, TASS reported

Shooting or killing polar bears is prohibited by the Russian government — however, culling the most aggressive bears might become "the only and necessary measure to ensure safety" in Belushya Guba if an alternative isn't found quickly, the government statement said.

The bears, meanwhile, are enduring a crisis of their own. Polar bears are considered a vulnerable species around the world as global warming continues to diminish their sea ice habitats. In the Arctic, where the world's estimated 22,000 to 33,000 polar bears live, average temperatures are warming twice as fast as the rest of the world, resulting in huge declines in sea ice every year, according to a December 2018 report released by the National Oceanographic and Atmospheric Administration (NOAA).

As sea ice melts, polar bears have to travel farther and work harder to catch seals, causing some to starve to death in the process. Others — like those that crashed Belushya Guba — would rather eat garbage, it seems.

• The Reality of Climate Change: 10 Myths Busted
• 10 Species You Can Kiss Goodbye
• The World's Biggest Beasts: Here and Gone

Originally published on Live Science.

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Polar bears live in a remote and inhospitable environment far from most human settlements. For most biologists, opportunities to observe these animals are fleeting. In fact, scientists' main resources for understanding basic behaviors of polar bears on sea ice are observations of polar bear behavior and foraging rates made by Canadian biologist Ian Stirling more than 40 years ago, combined with local traditional knowledge from Arctic indigenous peoples.

With ongoing and forecasted declines in Arctic sea ice, there is a greater need to understand how polar bears use sea ice and will respond to anticipated environmental changes. To answer this question, I have been studying polar bears’ physiology and foraging behavior in the Arctic since 2013 with colleagues from the U.S. Geological Survey, the University of California at Santa Cruz, the San Diego Zoo Institute for Conservation Research and Dr. Stephen Atkinson, an independent research wildlife biologist.

In a newly published study, we provide metabolic data showing, for the first time, how many seals bears need to catch while they forage on sea ice to survive. In doing so, we found they expend more energy than scientists had previously thought. This highlights their reliance on a diet of fat-rich seals in the energetically demanding Arctic.

How much energy do foraging polar bears need?

In the Beaufort Sea, where the USGS conducts research, polar bears have shown declines in abundance, survival rates and body condition. But it has been hard to directly quantify the mechanisms driving these declines.

Research suggests that bears are catching fewer seals and moving greater distances than they did historically, resulting in an energy imbalance that negatively affects their condition and reproductive success. But scientists have struggled to quantify how much energy free-ranging polar bears need and how many seals they need to catch to avoid this negative energy imbalance.

Improvements in animal research technology gave us an opportunity to gain insight into the metabolism, behavior, foraging success and movement patterns of polar bears on sea ice. However, these technologies were not designed to be used on polar bears in minus 30 degrees Celsius conditions, so it took several years to collect the information that we were seeking.

Sub-zero temperatures and wide-ranging bears

In 2013 we deployed collars equipped with GPS and video cameras on two polar bears to examine the bears’ behaviors and foraging success rates on sea ice. We managed to recover the collars 10 to 13 days later, but to our disappointment the camera lenses were covered with a solid block of ice. Still worse, the camera batteries had failed, probably due to cold temperatures, and no video had been recorded.

A year later we deployed four GPS video camera collars that had been custom-designed for us by wildlife video camera engineer Mehdi Bakhtiari to handle extreme Arctic conditions. We attached high-tech triaxial accelerometers, similar to the technology used in Fitbits, to the collars to help us measure the bears’ behavior and activity rate. We also analyzed measurements in blood samples that enabled us to determine their energy expenditure.

This time, the video cameras worked. When we recovered them, we had collected eight to 11 days of footage showing polar bears’ behavior on sea ice from a bear’s point of view, which we could link with the animals’ energy expenditures. But three of the four accelerometers had failed, again due to battery issues resulting from extreme cold conditions.

In 2015, after working with the accelerometer manufacturer, we managed once again to deploy 4 GPS video camera collars with triaxial accelerometers on polar bears. However, one bear had her heart set on moving to Canada and traveled roughly 175 miles (280 kilometers) in nine days after we collared her. To reach her, we flew in a helicopter to a village near the Canadian border, where we then were fogged in for 12 days. During that time the bear crossed into Canada, having walked nearly 270 miles (430 kilometers) since her collar had been applied. We remotely released her collar via satellite, and then waited for it to drift back into U.S. waters before making a dash to locate it.

Feast or famine

Despite these challenges, we were able to collect a remarkable suite of data on polar bears’ metabolism, behaviors, foraging rates and movement patterns. Our measures of metabolism were considerably higher than previous estimates of polar bear metabolic rates. In other words, we found that polar bears require more energy in their daily activities than scientists had previously believed – about 1.6 times more.

The video collars provided remarkable footage of polar bears’ feast-or-famine lifestyles. A bear could walk for hours before finding a seal breathing hole that interested her, and then spend minutes to hours waiting for a seal to come up for air. If that happened, the bear would stand up on its hind legs and pounce through the ice into the water to try to stun the seal, then grab its prey with its jaws and bite it at the neck. More often than not, the seal would get away and the bear would search for another breathing hole.

Of the 9 bears we studied, 5 lost mass over the eight to 11 days that we monitored them. Four of the bears lost almost 10 percent of their body mass – about 40 pounds (18 kilograms). In contrast, the four bears that actually caught and ate ringed seals gained almost 10 percent of their body mass. These large changes in body mass over such a short period of time were striking demonstrations of how heavily polar bears rely on an energy-dense diet of seal blubber.

Significantly, we also found a strong relationship between the bears’ activity levels and their metabolisms. Polar bears that were more active and moved greater distances used much more energy than less active bears.

Our findings reinforce the physiological challenges that polar bears face as sea ice shrinks and becomes increasingly fragmented. Their seal prey becomes less available, and the bears have to become more active and cover more distance to feed. While there has been much speculation about how loss of sea ice may affect polar bears, our research shows just how dramatically these animals may be affected if they have to range farther to find the food they need.

Anthony Pagano, PhD Candidate, University of California, Santa Cruz

This article was originally published on The Conversation. Read the original article.

A hard-to-watch video from Canada's Baffin Islands shows an emaciated polar bear in what were likely the last few hours of its life.

National Geographic photographer Paul Nicklen captured the sad sight on video and posted it online Dec. 5. The video shows the bear staggering toward a trash can and searching in vain for something to eat. It ends with the bear resting on the ground, exhausted. [Gallery: Stunning Photos of Polar Bears in the Arctic]

Nicklen told National Geographic he wants the footage of the dying bear to communicate the consequences of climate change.

"When scientists say bears are going extinct, I want people to realize what it looks like. Bears are going to starve to death," Nicklen said. "This is what a starving bear looks like."

Ice-bound hunters

Polar bears depend on sea ice to hunt seals, which fuel the bears with their blubbery, energy-rich meat. As the climate warms, the Arctic has been particularly hard-hit. Arctic sea ice reaches its maximum extents in late winter, typically around March, and melts in the summer, hitting its minimums around September. In recent years, ice has been forming later, melting sooner and covering less area. Record or near-record lows in ice extent have become standard each March, when the Arctic should be at its most frosted-over.

In March 2016, NASA scientist Walt Meier told Live Science that the Arctic has lost about half its volume at its maximum extents since record-keeping began. November 2017 saw an average sea-ice extent of 3.65 million square miles (9.46 million square kilometers), according to the National Snow and Ice Data Center, the third-lowest November extent on average since 1979.  

For polar bears, the loss of sea ice means the loss of hunting grounds. The International Union for Conservation of Nature lists the bears (Ursus maritimus) as "vulnerable," largely because of the loss of sea ice. Already, scientists have found that the loss of ice means polar bears must swim farther for food, a fact that puts cubs, in particular, at risk. Bears must also travel longer distances on foot over sea ice as the drift of the ice increases alongside melt, according to a 2017 study by the U.S. Geological Survey. Another study of bears fitted with tracking collars near Hudson Bay found that bears now spend more time on land, arriving earlier in the summer and leaving later in the fall, a pattern that means their seal-hunting season is limited.

Though polar bears do shift their diet to snow goose eggs, caribou and other terrestrial meals when on land, a 2015 study published in the journal Frontiers in Ecology and the Environment found that the calories from these sources aren't enough to offset what the polar bears burn in foraging.

Representative bear?

Of course, there is no way to know whether any given bear would have starved without climate change, or what the history of the bear in the video is.

Shrinking sea ice is causing polar bears to starve more often, but "[y]ou can't say that any one individual is starving because of climate change," Steven Amstrup, chief scientist at Polar Bears International, told Live Science in 2015 after a heart-wrenching photo of a skeletal polar bear circulated online. That's because polar bears do starve in the wild on a regular basis. As apex predators, they have no natural enemies to put them out of their misery when they become too old or injured to hunt, Amstrup explained.

Nevertheless, Nicklen's video shows what this looks like for bears that have an increasingly hard time hanging on in warming conditions. He filmed the video with tears rolling down his cheeks, he told National Geographic.

He's been asked why he didn't do something to help, he said, but it's illegal to feed wild polar bears in Canada, and there was little he could have done even if it weren't.

"[I]t's not like I walk around with a tranquilizer gun or 400 pounds of seal meat," Nicklen said.

Original article on Live Science. 

Hundreds of hungry polar bears were treated to a whale of a buffet last week when the carnivores descended on a whale carcass on the coast of Russia's Wrangel Island.

The incredible sight was photographed by tourists on a boating expedition that was traveling through the Northeast Passage.

"We were cruising down the coast and saw a 'herd' or 'convention' of polar bears on/near the beach," on Sept. 19, Rodney Russ, the expedition leader, wrote on his blog. Russ is the owner and founder of Heritage Expeditions, the New Zealand-based company that co-led the trip. [In Images: Polar Bears on Google Street View]

Russ immediately realized why the polar bears (Ursus maritimus) "of all ages, sexes and sizes" had congregated there: They were feasting on a dead bowhead whale (Balaena mysticetus), he wrote in the blog post. Russ counted more than 150 polar bears, although a statement issued by the Wrangel Island State Nature Reserve put that estimate at closer to 230 bears.

Intrigued, the tour group left their boat, the Akademik Shokalskiy (the same vessel that got stuck in Antarctic sea ice in December 2013) and boarded smaller vessels known as zodiacs to get a closer look at the seemingly ravenous bears.

"That is the memory we will all carry with us," Russ wrote. "There are no words to describe it."

It's possible so many bears attended the impromptu picnic because they smelled the rotting whale. Polar bears can smell seals up to 20 miles (32 kilometers) away, according to the San Diego Zoo. When they're not eating beached whales, the bears are known to eat ringed seals, walrus, caribou, grass and seaweed, the San Diego Zoo says.

Polar bears are listed as vulnerable to extinction, largely because human-made climate change is melting the Arctic sea ice where they live, according to the International Union for Conservation of Nature (IUCN).

It's unclear, however, whether climate change had made these particular bears hungrier than usual. The frequency of starving polar bears is expected to increase as the climate warms and sea ice declines — not just because of climate change directly, but because ice loss is taking away seals, their main food source, Steven Amstrup, chief scientist at Polar Bears International, a nonprofit research organization dedicated to studying polar bears, told Live Science in 2015.

The bowhead whale is listed as an "animal of least concern," meaning it is not at risk, the IUCN says.

This isn't the only bear-on-whale banquet in the books. In June 2016, a naturalist guide for a lodge in Alaska spotted a brown bear snacking on a sperm-whale carcass in the southeastern part of the state.

If you want to glimpse a polar bear on your own, watch the polar bear cam at the San Diego Zoo — just know these bears won't be eating any whales.

Original article on Live Science.

Often photographed clinging to Arctic ice floes as its habitat melts away into warming waters, the polar bear is the poster child for U.S. efforts to save wildlife on the brink of extinction using the Endangered Species Act.

But the act is quickly becoming a target of the Trump administration and Congressional Republicans who have introduced at least 11 pieces of legislation that could weaken it or prevent some threatened wildlife from being protected.  

The Endangered Species Act, or ESA, was signed into law by President Nixon in 1973 and helps to protect more than 1,600 plant and animal species considered threatened or endangered. Thanks in large part to the signing of that act, many iconic wildlife species on the brink of extinction have recovered over the past 40 years, including the bald eagle, American alligator, peregrine falcon and gray wolf.

The act also promotes resiliency to climate change by protecting habitat and helping maintain natural systems, benefitting both humans and wildlife — even those that are not listed as endangered or threatened, said Dave Owen, a professor of natural resources law at the University of California-Hastings.  

Related:

U.S. Lists First Bumble Bee Species as Endangered Not All Species Will Be Endangered by Climate Change Polar Bear Numbers to Fall as Arctic Ice Shrinks

"Wildlife habitat is also human habitat," he said. "Wild areas provide us with recreation, clean air, clean water, flood control, scenic beauty, and more."

While no legislation proposing to outright abolish the ESA has been introduced in Congress, a variety of bills introduced since January seek to weaken it and its ability to address climate change.

Some of the most significant bills that have been introduced this year that would impair the ESA include:

• The Stopping EPA Overreach Act. this bill would require federal agencies to make public all scientific data forming the basis for the government's decision to list wildlife as threatened or endangered. The bill is the result of Republicans' claim that poorly conducted science forms the basis of government determinations that a species is threatened or endangered, a position vigorously disputed by ESA supporters who say critics are trying to politicize science.

• Federal Land Freedom Act. A House bill sponsored by four Republicans, the Listing Reform Act aims to reduce the economic impact of listing a species as endangered by preventing the federal government from considering proposals for protecting a species based on how urgent it is to protect it from extinction. Instead, the bill requires the government to consider proposals in the order they were received.

Biologically diverse ecosystems are more stable than less diverse ones. So when temperatures rise, disease breaks out or invasive species spread, diversity protects and buffers against the changes, said Bradley Cardindale, director of the Cooperative Institute for Limnology and Ecosystems Research at the University of Michigan-Ann Arbor.

"Habitat loss is the single largest cause of species extinction worldwide, so the ability to preserve the habitat needed by species is the most powerful tool of the Endangered Species Act," he said. "Conservation of biological diversity provides people with insurance that the world will be able to produce their air, water and food even as the climate changes." When the George W. Bush administration listed the polar bear as threatened in 2008, it helped raise public awareness about the connection between global warming and the plight of iconic wildlife. But the Bush administration stipulated that the listing could not be used to regulate the greenhouse gas emissions that are causing the polar bear's habitat to melt away.

"The polar bear was the first species protected under the Endangered Species Act solely because of threats from global warming," said Shaye Wolf, climate science director for the Center for Biological Diversity, an environmental group. "The listing not only raised public awareness that climate change is already driving vulnerable species like the polar bear toward extinction, but also forced the Bush administration to adopt the consensus view of the world's scientists on global warming."

Listing the polar bear also highlighted the political limitations placed on the ESA to address climate change.

Few other laws have been as politically polarizing as the Endangered Species Act. Its critics say the law has a reputation for halting development projects on private land and dictating how public and private land is used in areas with endangered or threatened wildlife, ringing up high costs to local communities.

"Most of these costs are difficult or impossible to measure," said Jonathan Wood, an attorney for the Pacific Legal Foundation, which represents opponents of the act. "They're the homes that were never built, the businesses that were never started and the jobs that were never created because plans were dashed at an early stage when the person who would have created them learned of the challenges that ESA regulations would pose for her plans."

One of the most vocal anti-ESA members of Congress, Rep. Rob Bishop, R-Utah, told the Associated Press in January that he wants to "invalidate" the law because it has been "hijacked" by environmental groups.

"It has never been used for the rehabilitation of species," Bishop told the AP. "It's been used for control of the land."

Legislation weakening the ESA in the new Congress is alarming environmental groups that are pushing to keep the act intact.

Aimee Delach, a climate adaptation policy analyst for Defenders of Wildlife, an environmental group, said Congress could reduce the effectiveness of the ESA by removing the science that underpins it, or reducing the funding for the federal agencies that enforce the act. "Talk of 'modernizing the ESA' in the current Congress is doublespeak for 'weakening the ESA,' " Delach said.

The Senate held a hearing in February about modernizing the ESA, during which lawmakers criticized the act for failing to remove protections from imperiled species as they recover. But they said that the primary ways the government attempts to recover animals and plants on the brink of extinction threaten private property rights.

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Original article on Climate Central.

This article was originally published at The Conversation. The publication contributed the article to Live Science's Expert Voices: Op-Ed & Insights.

Our Earth has unimaginable diversity, from seascapes 8,000 meters below the ocean's surface to landscapes 8,000 meters above it. Its physical beauty comes in inconceivable living varieties. Some mammals lay eggs; some lizards are legless. Bats catch fish. Birds catch bats. Wood frogs in Alaska survive through winter even as two-thirds of their body tissues turn to ice.

But as climate alters habitats to which animals have spent thousands of years adapting, snow disappears more quickly now in some places and deepens in others. Receding sea ice strands polar bears on land and reduces the length of their hunting season. As permafrost at the bottom of Siberian lakes cracks, water drains into the ground; fish die.

My research focuses on conserving large species adapted to life in cold places, including the Northern Rockies, Central Asia, and on permafrost in both Asia and Alaska. This winter, for the 11th straight year, I am returning to the Arctic. I want to understand how changing temperatures may be impacting muskoxen – animals that once roamed with extinct woolly mammoths.

To address this issue, I need to discern population trends and possible stressors, and to gain insights into these animals' physiology, reproduction, predators and food sources. The overarching umbrella is a story of ice, snow and temperature.

A vulnerable Arctic

Earlier this year scientists from NASA and the National Oceanic and Atmospheric Administration released a sobering finding: According to independent studies by both agencies, 2016 was the third year in a row to set a new record for global average surface temperatures. Warming patterns are most extreme in the polar regions, particularly in the Arctic.

NASA animation of warming trends shows that polar regions are warming faster than lower latitudes.

One of the most striking trends we are observing in the Arctic is an increasing occurrence of winter days when temperatures never drop below freezing. Precipitation falls as rain, melting snow on the ground. This can be more serious than it sounds. In 2002 a winter rain-on-snow event on Canada's Banks Island encased the ground in ice and prevented muskoxen from reaching their food supply. Some 20,000 animals died.

Cold-adapted species are feeling the heat. Moose experience more ticks, caribou more pathogens from the south. As northern vegetation grows more profuse, some species lose habitat. Red foxes displace Arctic foxes.

We know of the enormous changes in polar environments because of creative interdisciplinary collaborative studies by teams of scientists from dozens of countries. But at fine-scale levels, we know less about how these changes are affecting individuals, or how much flexibility many species have to adapt.

Research on American ice

Logistics related to traveling in the Arctic are significant year-round, and especially complex in winter. In Alaska, I work with two assistants and we travel light. Typically, it is just Fred Goodhope Jr. (a Native Alaskan whose ancestors survived here for 12,000 years), a bio-technician, and me. Fred knows these lands like the back of his hands, whether he is fixing the throttle of a snowmachine with dental floss at 10 degrees below zero or navigating ground blizzards without GPS.

Muskoxen occur in tightly knit herds, at times 50 kilometers apart. We navigate the tricky ice and tundra between the groups and gather data. For years, my colleagues and I used helicopters to pursue, tranquilize and radio-collar muskoxen. This was a very useful way to garner biological insights, but I abandoned it five years ago because about 5 percent of the animals that we radio-collared failed to reconnect with their herds when the drugs wore off. Instead they sheltered alone in snow-holes for safety for up to two months.

I wanted more compassionate ways to collect data, so I continue to gather and analyze frozen poop sans radio-collaring. It contains iced hormones that we can assess to infer stress levels (gluco-corticosteroids) and pregnancy rates (progestagens). We know from these data that isolated females experienced stress levels three to six times greater than their companions back in the herd. The change to gentler tactics has been well worth it.

We also use a method called photogrammetry, or making measurements from photos. When muskoxen perceive a threat, they stand clumped together in defensive formations rather than fleeing. Working with animals the size of a Volkswagen has benefits: They stand out in the vast Arctic. We can approach them when they group up this way and photograph them at known distances and angles, then use these shots to develop algorithms and estimate their sizes.

By comparing our estimates with data on the growth and size of captive animals, we can explore how factors like winter and summer temperatures, availability and health of vegetation, and rain-on-snow events affect wild muskoxen's growth and size.

Poorly fed or otherwise stressed juveniles from many species tend grow slower, achieve puberty later in life and have reduced survival. I want to learn about these parameters in muskoxen. For example, during rain-on-snow events, pregnant females cannot eat because their food is locked under impenetrable ice. My colleagues and I expect that their growing fetuses deplete the resources that are available to them in utero, and that these stores are not replenished because food is unavailable to the mothers. We are now developing our first estimates of how warming temperatures may be affecting this little-studied species.

Research on Asian ice

In both Greenland and the High Canadian Arctic there have been limited reports of polar bears eating muskoxen, but we do not know whether they are feeding on dead animals or hunting live ones. We know that polar bears are foraging more frequently on land as the Arctic warms, melting the sea ice where they normally hunt, rest and breed. To determine whether polar bears are a threat to muskoxen, we need to know whether they are feeding on animals that have died from other causes such as disease, or are attacking live muskoxen.

I use a common experimental technique: simulations, which requires a fake polar bear and, as a control, a fake caribou. I take these two costumes, fashioned from cloth and Styrofoam, into the field and do approaches to muskoxen to see how they will react. This research follows in the footsteps of Nobel Laureates Niko Tinbergen and Konrad Lorenz, who were interested in animal behavior and manipulated the perceptual worlds of gulls and geese.

Now such field deployments are more common. Recently they have been used in the gas fields of Wyoming to assess how sage-grouse react to increased noise generated by fracking. I have also used acoustic and olfactory models in Alaska and the Yellowstone region to sort out how naïve prey like moose respond to reintroduced wolves and recolonizing grizzly bears.

On Wrangel Island in the Arctic Ocean, my apprehension heightens as I approach muskoxen herds on all fours. There is always a possibility of being gored, yet for my protection I can't carry a gun, and it's too cold to pepper spray when they charge. But I can leap from the ground onto my feet, which confuses them and halts any charges.

At the edge

Across Earth's vastness, humans have done a marvelous job of erasing or threatening the living magnificence that has come before. Field research gives me opportunities to look at the world through the eyes of animals, and to work with many other scientists to configure plans to do better for all living beings who rely on our planet's life support systems.

Cold-adapted species have figured out how to survive across thousands of generations. To dampen climatic challenges, we humans need to modify our behavior in a far shorter time frame.

Joel Berger, Barbara Cox Anthony Chair in Wildlife Conservation, Colorado State University

This article was originally published on The Conversation. Read the original article.

New footage from a polar bear body cam shows how these ursine inhabitants of the Arctic play, swim and hunt.  

Just released by the U.S. Geographic Survey, the footage is from a point-of-view camera around the neck of a female polar bear from the southern Beaufort Sea, just north of Alaska. According to the USGS, scientists fitted the female with the camera to track her daily activities, behaviors and feeding rates.

The footage captures a bear's-eye-view of the world as the female plods across the ice, chows down on a seal, has a play fight with another polar bear and swims in the ocean. The goal of the project, according to the USGS, is to better understand how polar bears are responding to declines in sea ice in the Arctic.

Polar bears (Ursus maritimus) were listed as threatened under the Endangered Species Act in 2008. The main reason for the listing, according to the U.S. Fish & Wildlife Service, was the continuing loss of sea ice, which threatens the bears' ability to hunt for seals during the winter. A 2015 study in the journal Ecological Applications found that polar bear populations in the southern Beaufort Sea declined between 25 percent and 50 percent from 2001 to 2010.

The International Union for Conservation of Nature (IUCN) estimates that there are about 26,000 polar bears split into 19 different populations across the Arctic. The bears prey mostly on ringed seals and bearded seals, according to conservation organization Polar Bears International, which is what makes them so vulnerable to Arctic melt. As the fall freeze comes later in the Arctic and the spring melt starts sooner, bears are stuck on solid ground, unable to hunt seals, according to a 2013 review article in the journal Topics in Companion Animal Medicine.   

"Polar bears have few alternatives if their habitat (the sea ice) and their access to their ringed seal prey rapidly disappear," the author wrote.

And sea ice is rapidly disappearing. Scientists have been observing record lows in ice extent for years and now predict that the Arctic may be entirely ice-free in the summerby the middle of the century. This year, sea ice in the Arctic actually retreated briefly in November, an event scientists said was virtually unprecedented. Winter sea ice has been seen to retreat only once before, in November 2013, but that drop was 5,400 square miles (13,986 square kilometers) compared to 2016's 19,300 square miles (49,987 sq km).

Original article on Live Science.

SAN FRANCISCO – Santa Claus better stock up on reindeer, because he may have trouble scrounging up replacements in the not-too-distant future, new research suggests.

Reindeer populations in northern Russia are falling, according to a new study. The new findings dovetail with other research showing that reindeer populations are falling in other parts of the Arctic as well.

But Santa's trusty steeds aren't the only iconic wintry beasts facing worldwide declines. Polar bear populations could decline by about one-third over the next 30 or 40 years based on sea ice estimates, another study found. [6 Surprising Facts About Reindeer]

And hotter, drier conditions in the western U.S. could mean steep reductions in mountain lion and mule deer populations.

Worldwide changes

For a while now, scientists have documented many changes in the Arctic that suggest trouble is brewing.

"The reindeer population in the world, and caribou, are declining pretty rapidly," study co-author Andrey Petrov, a geographer at the University of Northern Iowa, said here today (Dec. 12) at a news briefing at the annual American Geophysical Union Meeting. "We don't know why it's happening."

To get a better understanding of why, Petrov looked at reindeer populations in the Taimyr Peninsula in Far North Russia. The Taimyr reindeer population, at 600,000 animals, makes up 24 percent of the global reindeer population. The population peaked in 2000 at more than 1 million creatures, after the dismantling of the Soviet management system led to dramatic reductions in hunting. However, since then the population has been falling.

Petrov used satellite views of the region's vegetation, along with the vegetation and the corresponding presence of reindeer. The herds of reindeer are clearly visible in land satellite imagery, which allowed Petrov to map reindeer movement across the Arctic during the winter, their spring calving season and summer. He found that, overall, the reindeer have a strong tendency to return to the same places over and over again.

But there were some changes. Warming conditions meant that mosquitoes flourished at lower latitudes, so reindeer were venturing farther north during the summer season, possibly to avoid mosquito harassment, Petrov said. That meant they had a longer migration from their southern winter grounds.

Climate change also had other impacts, especially on the vulnerable young calves.

"Rivers that are historically frozen solid were melting earlier in the season," Petrov said at the briefing. "They have to swim across open rivers. That's one of the reasons we believe the population is declining."

Another study, presented Dec. 12 at the British Ecological Society meeting in Liverpool, England, found that adult reindeer living on Svalbard, a Norwegian archipelago located between Norway and the Arctic, are shrinking in size, likely due to climate change. 

Polar bear plunge

Polar bear numbers will also likely fall in the next several decades, said Kristin Laidre, a principle scientist at the Polar Science Center at the Applied Physics Laboratory in Seattle. Laidre and her colleagues used satellite imagery to map sea ice in different regions of the Arctic over time.

Past studies have looked at individual populations, and in many areas, data is poor, with just a few years of population data rather than annual trends, making it hard to create a global prediction of polar bear trends. However, because polar bears require sea ice for hunting, declines in sea ice extent can be a strong predictor of animal population declines in the future, Laidre said.

Her team found that sea ice declines around the world lead to about a 70 percent chance that the polar bear population will drop from 26,000 bears to about 17,400 over the next 35 to 40 years.

Shrinking wild spaces

Changes in the climate will also affect the western desert area of the U.S., said David Stoner, a researcher with the Department of Wildland Resources at Utah State University.

Stoner used satellite imagery to map the vegetation changes from 2000 to 2014 in the western United States. He found that during the drought of 2002, the abundance of available vegetation that mule deer eat contracted to the mountainous regions, and less of the Mojave Desert and other dry regions had enough greenery to sustain the population.

At the same time, the actual abundance of mule deer dropped by about 20 percent, with the deer occupying a smaller area. Even though mountain lions don't eat grass (mule deer make up about 60 percent of their diet), the declines in vegetation also led to a dramatic drop in mountain lion populations as well, Stoner said.

"We were very surprised that the vegetation indices were very good predictors of mountain lion abundance as well, even though they exhibit only an indirect relationship with vegetation," Stoner said.

Paradoxically, the dwindling mountain lion population may mean more conflicts with humans. As fewer mule deer survive in the wild, they may venture out into the manicured greenery of human landscapes.

"Agriculture and urban landscapes are irrigated and fairly consistent. As conditions in native habitat diminish, it makes those human landscapes all the more attractive and appealing," Stoner said.

Mountain lions, meanwhile, may have to roam farther to find food, which also increases the risk of clashes with humans, he added.

Original article on Live Science.

Five meteorologists surrounded by polar bears at a research station on a remote island in high-Arctic Russia have been rescued, according to the Guardian. A Russian research vessel happened to be close by and has arrived on scene, supplying dogs and flares that have since scared the polar bears away from the research facility.

The scientists had been trapped in their facility by a pack of polar bears that had staked out the area.

According to the Russian news agency TASS, approximately ten adult bears, along with some cubs, were stalking the grounds around the Izvestia CEC weather station, on the Troynoy island in the Kara Sea, about 93 miles (150 kilometers) off the coast of Siberia.

RELATED: Are Polar Bears Saving Themselves?

The researchers were trapped at the site for two weeks, NBC News reported. Their only defense against the enormous creatures was the used of flares to frighten the large, potentially deadly, animals. But their flare supply had run out, and the researchers were forced indoors.

It was originally thought that help might not reach the scientists for another month, when a scheduled supply boat would arrive.

TASS reported the bears were so close that some of them were sleeping under the windows of the research facility.

"The bears live in the Arctic, you know. We can't ban them from hanging around," the station's supervisor told NBC.

TASS noted that polar bear hunting has been banned in Russia for more than 50 years, due to the animal's worldwide endangered status. Russia's Minister of Natural Resources and Environment, Sergey Donskoy, ordered that every measure possible be adopted to protect both the bears and the scientists.

RELATED: Hungry Polar Bears Decimating Seabird Colonies

The scientists had halted all outdoor observations. They were stocked for work in year-long shifts, according to NBC, and were not in any immediate peril.

"Things like this have happened before on the Troynoy island because bears inhabit the area and people work there," Vassiliy Shevchenko, the head of the Sevgidromet State Monitoring Network, which owns the weather station, told TASS. "At the end of October, or in the beginning of November the near-shore waters will freeze and the bears will leave the island in search for food," Shevchenko said.

Original article on Discovery News.

While the iconic images of polar bears in a warming world are arguably of starving bears shivering on ice floes, or of bears swimming great distances as those floes disappear, a different scene may be a more accurate portrayal of the animal's near future: hungry polar bears decimating colonies of nesting seabirds.

"Picture instead," writes Daniel Grossman in a post for Yale Climate Connections, "a cream-colored bear loping on land, across tundra, and along the pebbled shores." Forced to venture ashore in search of sustenance, this hypothetical bear is fighting off hunger by snacking on bird eggs.

The image is fully grounded in fact. As Grossman notes, polar bears have increasingly been observed marauding through colonies of seabirds as they seek alternate sources of sustenance in the absence of sea ice.

Polar Bears Found Rock Climbing in the Arctic

A 2010 study, for example, documented four cases of polar bears eating snow goose eggs, and the chicks and eggs of thick-billed murres, in Arctic Canada – with the bears in some instances even clambering up cliff faces to reach the nests.

And just last year, a team of European researchers reported that, in Greenland and the Svalbard Archipelago, bear raids on colonies of common eiders, glaucous gulls and barnacle geese, rarely if ever seen before 2000, are now commonplace.

Some scientists have argued this shows that concern over polar bears' future is overstated and that the species may be able to survive the absence of their usual sea-ice-dwelling seal prey by switching to birds and to coastal Arctic land mammals such as caribou.

Video: Why Polar Bears Don't Hibernate

Theirs, however, is very much a minority position; others have calculated that such terrestrial food intake is "insufficient to offset lost ice-based hunting opportunities," although they warn that it "can have ecological consequences for other species."

This is what concerns Jouke Prop, a Dutch ornithologist who was one of the team that reported its findings from Greenland and Svalbard. He has observed polar bears eating more than 200 eggs in two hours; in 2014, no chicks or eggs of any of the three species species at his study sites survived.

According to a 2012 study, the combined effects of polar bear predation and parasitism by mosquitoes (itself likely also increasing as a result of higher temperatures) reduced the overall productivity of a thick-billed murre colony in Canada's Hudson Bay by 20 percent in one year, and also increased adult mortality by 20 percent.

Arctic Grizzlies Bully Polar Bears

"If this effect happens every year," the study's authors concluded, "it will have population consequences."

Originally published on Discovery News.

He spawned millions of fuzzy toys, garnered media attention on everything from his cod-liver diet to his lack of mates and even inspired his own song before his untimely death in 2011.

He was Knut the polar bear, the star of the Berlin Zoo.

Now, new research shows how the adorable white beast really died.

It turns out that Knut was killed by an autoimmune disorder called anti-NMDA receptor encephalitis, a kind of brain inflammation. Past work implicated encephalitis in his death, but hinted that a virus or bacteria was to blame.

The new discovery suggests that a disease previously identified only in humans could be a leading cause of encephalitis deaths in other animals, study co-author Alex Greenwood, a veterinary physiologist at the Leibniz Institute for Zoo and Wildlife Research in Berlin, said in a press briefing. [See Images of the Adorable Polar Bear Knut]

A life full of drama

The twists and turns of Knut's life captured the popular imagination. His mother Tosca rejected him at birth (Dec. 5, 2006), and his brother, who was born the same day, died just four days later. So the zookeeper Thomas Dörflein bottle-fed Knut, forming a deep bond with the cub. Videos of Dörflein swimming and snuggling with Knut were Internet sensations.

"You had this immediate charismatic contact between human and animal," Greenwood said.

When Dörflein died suddenly of a heart attack in 2008, it was as if Knut was orphaned again. And Knut had a difficult time as a grown bear. He was rejected by potential mates and constantly fought with other polar bears and was separated from them.

Even his death was spectacular. On March 19, 2011, Knut had a seizure and collapsed, falling backward into his pool, dying in front of hundreds of zoo visitors.

Encephalitis

A tissue sample taken from Knut shortly after his death revealed he had encephalitis, with a 2014 study hinting at an infectious virus as the cause. But a closer analysis revealed antibodies, or immune cells, to the influenza virus, but no actual flu virus particles present. None of the inflammation seemed tied to an active infection, the researchers said.

"We basically had ruled out any pathogen imaginable with a very comprehensive search using all the most modern methods and next-generation sequencing and all the classic methods of serology, and we just didn't find anything," Greenwood said. (Serology refers to the study of body fluids, often the identification of antibodies in blood serum.)

But when Harald Prüss, a neurologist at the German Center for Neurodegenerative Disorders (DZNE) Berlin and Charité, read the report on Knut's death, he thought the case sounded a lot like the human disease he treats in his clinic, known as anti-NMDA receptor encephalitis. [Top 10 Mysterious Diseases]

The rare disease occurs when antibodies, the immune cells designed to recognize foreign agents, bind to glutamate (NMDA) receptors in the brain, causing them to malfunction. Anti-NMDA receptor encephalitis affects about one in 200,000 people, and initially causes fever, headaches and psychosis before progressing to motor problems, seizures and death if undiagnosed and untreated. It is the major cause of encephalitis in humans when no virus or bacteria can be blamed, yet it was only discovered in 2007.

Luckily, the disease can be mostly reversed if caught early enough, Prüss said in the briefing.

"We usually try with high-dose steroids during the first days, and then in some patients, plasma exchange — plasmaphoresis — is quite efficient in removing these antibodies," Prüss said.

The team analyzed Knut's brain and found signs of NMDA antibodies at his glutamate receptors, the researchers report today (Aug. 27) in the journal Scientific Reports. It's not clear exactly why his body began to attack his brain, but in humans, a recent case of influenza or herpes can sometimes trigger the body's friendly fire, Prüss said.

Widespread animal disease

The new results raise the possibility that anti-NMDA receptor encephalitis is relatively common across the animal kingdom. So theoretically, zoo animals and even some endangered species in the wild could potentially get treatment, Greenwood said.

Of course, animals can't talk, so veterinarians only suspect encephalitis when they start to have seizures or motor problems. Veterinarians would likely give sick zoo animals a cocktail of antivirals, antibiotics and immune-suppressing drugs as soon as they show those symptoms, to try to eliminate the antibodies, Greenwood said.

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

Margaret Williams, managing director of the Arctic program at World Wildlife Fund (WWF), contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

Living in Alaska, I have seen firsthand that the Arctic is rapidly changing. It's always been a land of extremes (weather, daylight, terrain), but now even the tundra can catch fire.

Warming air and sea temperatures are wreaking unprecedented havoc on the landscape around the state, shrinking sea ice, increasing coastal erosion and fueling fires across Alaska's landscapes. Fires can easily start due to the increase in dry weather. The residents of this region are at serious risk of losing their homes and ways of life. This environment has also put the Arctic's unique wildlife in trouble, particularly ice-dependent species such as polar bears.

In 2008, polar bears were listed under the U.S. Endangered Species Act (ESA), specifically because of the projected effects of climate change on their habitat. Recent modeling by the U.S. Geological Survey (USGS) has also shown the need to reduce greenhouse gas emissions in the atmosphere to prevent declines in polar bear populations.

In a crucial development, on July 2 the U.S. Fish and Wildlife Service (FWS) released its draft plan to conserve polar bears, calling for timely and decisive reduction of greenhouse gas emission levels to curb climate change. Emissions reductions are the only way to curb the threat to polar bear habitat , and it is essential for the public to call for immediate action on the FWS recovery plan. 

The natural need for ice

As an ice-dependent Arctic species, polar bears are especially vulnerable to changes in sea ice , which is predicted USGS to disappear before 2050. The ice-free period is expected to lengthen after that. 

Polar bears use sea ice as a platform for hunting seals, the bears' primary prey, and when sea ice disappears in the summer, the bears must retreat to land away from those hunting areas. [Polar Bears Now Eat Dolphins, Thanks to Global Warming ]

These longer, ice-free periods mean that during the summer, polar bears will have to rely on their stores of fat. They may find a few things on land to eat, but as animals that have a huge energy requirement, they depend on the fatty, high-calorie marine mammals that also live on the sea ice. Polar bears are good at feasting while there's food, and fasting while there's not, but their fat reserves can only last so long. 

Ice-free periods longer than four months will likely cause declines in polar bear populations.

Those hungry bears will look for food wherever they can, including the towns and villages of the Arctic. A polar bear's keen sense of smell will lead it to garbage dumps, stored meat and sometimes even sled dogs. These visits will often end badly for polar bears. 

Drilling into the polar bear population

Aside from the threat of climate change, another immediate threat to polar bears is the growing push for offshore oil and gas development across the Arctic Ocean. 

The U.S. government, under the Bureau of Ocean Energy Management, has just given preliminary approval for Royal Dutch Shell to conduct exploratory drilling in the Chukchi Sea, where one of the two U.S. polar bear populations lives. 

The potential for spills from offshore oil and gas development is concerning. Oil spills can travel for miles in harsh Arctic waters, fouling key polar bear habitat, harming polar bear prey and stressing the entire Arctic food chain. 

Unfortunately, the FWS draft polar bear recovery plan does not adequately address the clear and present threat offshore drilling poses to the Arctic, an omission that requires re-evaluation.

The plan rightly outlines actions for sustainable co-management of subsistence harvest, protecting habitat for denning, when the females dig maternity dens in late fall to have their cubs, managing human-polar bear conflicts and conducting further research on polar bear populations. The plan will not only be used for polar bear conservation in the United States, but will also be part of an Arctic-wide conservation action plan being developed by the five polar bear "range states:" the United States, Canada, Denmark, Norway and Russia.

A team of more than 30 polar bear experts, including WWF staff, has collaborated with FWS over the past several years to map out a path toward polar bear resiliency in the Arctic. 

By recognizing and calling for the need to first address climate change, we have a chance to reduce the threats to polar bears and other Arctic inhabitants currently suffering from the regions seeming disorder. The newly announced plan will now serve as a roadmap for collective action by multiple U.S. agencies toward recovery of polar bear populations. 

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

For the first time, scientists have reported polar bears preying on white-beaked dolphins in Svalbard. The sighting, described in the journal Polar Research, is important because shrinking polar bear habitat is expected to change where the animals can live, particularly in the area of Svalbard and the Barents Sea, the researchers say. Images captured of the Svalbard polar bears reveal their lives in the Norwegian High Arctic. [Read the full story on polar bears eating dolphins]

First bite

On April 23, 2014, scientists observed an adult male polar bear preying on two white-beaked dolphins (Lagenorhynchus albirostris) that were trapped in the ice on a small fjord in Svalbard, Norwegian High. (Photo Credit: Jon Aars / Norwegian Polar Institute, Polar Research (http://dx.doi.org/10.3402/polar.v34.26612))

Dolphin Head

Here, the adult male polar bear feeds on the head of the white-beaked dolphin on a fjord on Svalbard, a group of islands in the Norwegian part of the Barents Sea area. (Photo Credit: © Samuel Blanc / www.sblanc.com)

Cover up

When the scientists spotted the male polar bear, he had eaten most parts of one dolphin (labeled dolphin B by the researchers) and was in the process of covering the second dolphin, this one mostly intact, with snow. (Photo Credit: Jon Aars / Norwegian Polar Institute)

Caching behavior

The researchers noted that such "caching behavior" is not typical for polar bears, since the animals consume most of the fat from their kills within a day, which isn't a lot of time during which they need to keep the carcass away from competitive scavengers. (Photo Credit: Jon Aars / Norwegian Polar Institute)

White-beaked dolphin

"White-beaked dolphins are frequent visitors to Svalbard waters in summer, but have not previously been reported this far north in early spring," the researchers write online June 1 in the journal Polar Research. "We suggest they were trapped in the ice after strong northerly winds the days before, and possibly killed when forced to surface for air at a small opening in the ice." (Photo Credit: Jon Aars / Norwegian Polar Institute)

A wide fjord

The dolphin-carcass eating occurred on Raudfjorden, a wide fjord on the coast of Spitsbergen, which is the largest island of the Svalbard archipelago. Here, Magnus Andersen with the white-beaked dolphin carcass. (Photo Credit: Jon Aars / Norwegian Polar Institute)

Dolphin pod

During the following summer and fall, which were both ice-free for Svalbard, researchers saw seven white-beaked dolphin carcasses around the same area. And at least six different polar bears were seen scavenging on the carcasses. The researchers think the dolphins were likely from the same pod as the earlier one, due to their locale and level of decay. These dolphins probably also got trapped in the ice in April. Here, the remains of the dolphin eaten by an adult polar bear. "Little more than the spine, rib cage and skull of dolphin B remained when we found it," they wrote in the journal article.

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Even though some polar bears are hunting on land more often in areas hit by climate change, a diet of bird eggs and berries can't sustain these huge animals, a new study finds.

Only a handful of polar bears have been spotted snacking on land-based foods to supplement their traditional, blubber-rich diet of seals and marine mammals. But researchers have wondered whether the high-protein, high-carbohydrate foods polar bears eat on land — such as caribou and berries — could help these symbols of the perils of climate change survive, as sea-ice loss makes seals harder to snatch.

It turns out the calorie trade-off isn't worth it, according to the study, a review of previous research on bear diets published today (April 1) in the journal Frontiers in Ecology and the Environment. The biggest bears on the planet, polar bears spend so much energy searching for berries or chasing down caribou that they reap little caloric reward from these meals. [In Images: Polar Bears' Shifting Diet]

"A really large bear has high energetic costs when they get up to forage, and these [terrestrial] resources are typically lower in calories or widely dispersed," said Karyn Rode, lead study author and a U.S. Geological Survey research wildlife biologist in Anchorage, Alaska.

Polar bears get all the calories, vitamins and minerals they need from their traditional diet, which is the fattiest of any animal on Earth. But their nearest geographic cousin, the Arctic grizzly, struggles to find enough food.

Rode points out that Arctic grizzlies are the smallest of all grizzlies. These aren't the giant brown bears that gorge at Southeast Alaska salmon streams. Arctic grizzlies are just a quarter the size of polar bears, Rode said. "The first time I saw an Arctic grizzly I was laughing, it was so small," she told Live Science.

Polar bears typically spend 85 percent of their time on land, resting and fasting. A grizzly, on the other hand, forages all the time, Rode said.

Finally, even if a few polar bears do make bird eggs and other terrestrial foods an important part of their diet, the bears may gobble so many eggs that they might decimate the Arctic seabird population. "Terrestrial foods can't offer polar bears what they need at a population level," Rode said.

Global warming has reduced the amount of Arctic sea ice near shore, especially in the late spring when polar bears hunt for seal pups before moving onto land for the summer. Polar bears mainly hunt for seals on the sea ice. The shrinking sea ice is sending the bears to shore earlier in the season in some areas of the Arctic, such as Hudson Bay, Canada, and their arrival overlaps with hunting opportunities for geese, eggs and caribou.

However, polar bear populations are stable in other Arctic areas, such as the Chukchi Sea between Alaska and Russia, Rode said. And the availability of marine prey could change as new species move north to claim warming ocean waters.

"If terrestrial feeding can't help, there are other things we need to be thinking about," Rode said.

Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.

As the largest land carnivores currently on the planet, polar bears are fearsome predators and the masters of their Artic domain. But do these hulking animals also have a softer side toward each other, or are their mating behaviors just as cold and unforgiving as their frozen habitat?

Polar bears (Ursus maritimus) are generally solitary creatures that only come together to mate during the breeding season, which typically runs from late March to early May. 

"In spring, what the males do is just roam around and try to pick up females," said Jon Aars, a polar bear researcher with the Norwegian Polar Institute, adding that the animals have powerful noses and likely track potential mates by scent. "They have little problem locating females."

It's not unusual for a male to track and follow a female for many miles, and males may even try to herd a female to isolated areas on the top of islands, in small bays or up on high cliffs, in an attempt to monopolize mating and reduce competition from other mates. 

However, observational studies suggest these attempts fail more often than not, given that females are frequently seen among groups of competitive males. 

Polar bears are sexually dimorphic and males are, on average, are about twice the mass of females. They also have "guard hairs" on their forelegs that are noticeably longer than those on females. 

These hairs are probably ornamental, but just what purpose they serve is unclear. Scientists hypothesize males' long guard hairs may help them appear larger, making them more attractive to females and seem tougher to rival males.

But males do more than just size each other up and wait for a female to choose her mate — they engage in fierce battles, which can result in broken canines, temporary wounds and permanent scars, and typically end when the dominant male chases all its rivals away. 

"When we've captured bears in spring, they have lots of scars, both old scars and new scars," Aars said, explaining that male-male fights aren't exactly rare occurrences. 

Once the female goes into estrous (heat), she and her male champion will mate, with the male mounting the female from behind. Studies of captive polar bears suggest pairs copulate for around half an hour, but copulation times may differ in the wild. In a 2015 study in the journal Polar Research, Aars and his colleague Thomas Smith reported observations of a pair mating for 65 minutes.

Mating induces ovulation in the female, and a male will guard and repeatedly mate with a female for up to 10 days to better his chances of fathering cubs. "He will stick around for however long he thinks it's worth it to guard the female," Aars said. 

After a pair separates, they may go on to mate with other polar bears. Male and female polar bears may have multiple mates in a single breeding season and, as Aars and his colleagues reported in a 2009 study in the Canadian Journal of Zoology, this can sometimes result in litters with multiple paternities.

Female polar bears undergo delayed implantation; that is, their fertilized eggs don't implant until the fall, when the mothers-to-be have gained considerable weight. About two months later, by early January, they give birth. They won't mate again for another 2.5 to three years, after the cubs have been weaned. 

But if a female's cubs die prematurely — whether by environmental factors or at the claws and teeth of adult males — she may go into estrous early, and even mate during the summer if she's already missed the spring breeding season, Aars said.

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Satellite photos could be a promising way to track the habits of wildlife in remote, inaccessible parts of the Arctic, a new study finds.

By snapping satellite images of polar bears in the Canadian Arctic, researchers found they could gather information about the mammals almost as accurately as ground surveys, and at a decreased cost.

"The key finding and why we think [satellite technology] has a potential use as a tool is that there's pretty high concordance between the abundant estimate derived from aerial surveys and from satellite," said study co-author Todd Atwood, a wildlife biologist at the U.S. Geological Survey's Alaska Science Center in Anchorage. [Photos of Polar Bears Swimming in the Arctic]

With Arctic sea ice melting at a quicker pace in recent years, animals living in the region are losing the habitats they have relied on for years. Organizations have struggled to monitor the migrations of these animal populations, resulting in a lack of long-term data for species like the walrus, ribbon seal and polar bear, according to the International Union for Conservation of Nature (ICUN). This deficiency highlights the need to find alternative ways to monitor these animals.

Biologists at the University of Minnesota use satellites to capture images of polar bears in Foxe Basin, Nunavut, in the Canadian Arctic. Using these photos, the researchers identified 92 bears — a number that roughly matched the 77 bears counted in an aerial survey.

The researchers chose to focus on polar bears because the mammals are categorized as a threatened species by the IUCN; climate change, pollution and human activities have encroached on their natural living habitats.  

But using satellite technology to monitor wildlife has its limitations. Aerial surveys can identify specific demographics, such as family groups and polar bear cubs, since planes can fly close to the ground. One aerial survey counted 28 polar bear family groups, while the satellites in orbit could spot only five.

"I think we don't know if [satellite imagery] will change how we monitor mammal populations yet," Atwood told Live Science. Nevertheless, he says, the findings show satellites have their advantages.

"It's suggestive that we can use finely resolved satellites in some of the more remote parts of the planet where there are logistical issues that constrain or prohibit monitoring — this satellite image approach allows us a tool to monitor areas that we'd have a difficult time getting to," Atwood said.

And, while aerial surveys can be used to reach remote places, they are extremely costly.

In the past, researchers used satellite technologyto track populations of Weddel seals and the emperor penguins in Antarctica. But these previous studies lacked a way to compare data gathered by satellite compared to data gathered on the ground — making it hard to discern how promising satellite technology could be.  

"I think the next step is to expand the scope of the area," Atwood said. "We chose Arctic Canada because there’s little topographical character, so it's easy to see the bears. So if those satellite techniques need to expand, we need areas with more complex topography and where bears aren't so easy to see.”

Atwood said researchers will also need to develop an algorithm or method to better analyze the satellite images. The findings were published online today (July 9) in the journal PLOS ONE.

Follow Jillian Rose Lim @jillroselim & Google+. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Polar bears nuzzle potential mates and play soccer with a frozen seal carcass in an amazing new video captured by collar cameras attached to the iconic animals.

This rare peek at Arctic life is part of an ongoing research project led by the U.S. Geological Survey that aims to track the health of Alaskan polar bears. The USGS said this is the first point-of-view video ever recorded from free-ranging polar bears.

"None of us have ever seen anything like this before," said Todd Atwood, leader of the polar bear research program at the USGS' Alaska Science Center in Anchorage. "It's a 'gee-whiz' feeling, seeing through the eyes of a polar bear."

The collar cams also serve as fitness trackers for the polar bears: Each collar is equipped with an accelerometer, a device similar to the gadget in a fitness tracker that records a person's movement.

When combined with video, scientists can decode the collar's movement data — whether the bears are eating, hunting, swimming or walking. The information will help researchers gauge how much energy the bears expend during their daily activities. [Gallery: Stunning Photos of Polar Bears in the Arctic]

But the videos revealed more than the bears' calorie count. Some of the behaviors recorded on camera had never been seen before — for instance, one polar bear plunked its frozen seal carcass into the sea.

"These animals are hard to observe in a natural setting," Atwood told Live Science. "This gives us a very unique insight into what they do on a daily basis."

Researchers speculated that the seal-dipping bear might have been warming the icy seal to make it more palatable, or perhaps the bear was playing with its food as part of a mating ritual with a nearby male.

Watching a changing world

USGS scientists are studying Alaskan polar bears to see how the animals respond to changing sea ice conditions. The growing distance between the Alaska coast and summer Arctic sea ice means polar bears have to travel farther, and burn more energy, to reach their traditional hunting areas.

Studies from the research project have found that polar bears are swimming longer distances, fasting for longer periods and spending more time onshore because of the decline in summer sea ice, Atwood said.

The Arctic is warming rapidly due to climate change, and the climbing temperatures are having a complex effect on Arctic sea ice. In some regions of the Arctic, there is less winter sea ice, but in other spots — such as the Bering Sea — there is more winter ice. Overall, though, there is significantly less summer Arctic sea ice now compared to in past decades.

Polar bears were listed as threatened in 2008 on the endangered species list due to the ongoing loss of their sea ice habitat.

This April was the first time the USGS successfully recorded video from polar bears. A trial run in 2013 failed because the collar camera, from a commercial company, froze under Arctic conditions. The batteries failed, and the lens iced over, Atwood said.

When scientists returned this spring, Anthony Pagano, a University of California, Santa Cruz, wildlife biologist who is leading the study, used custom-built collar cameras designed by private contractor Exeye. Pagano attached four collars to female polar bears who live near the southern Beaufort Sea.

The cameras can store 38 hours of video, and are programmed to turn on when temperatures are above freezing, so the lens isn't iced over during filming. The collars drop off after eight to 10 days.

"They worked fantastically," Atwood said. The USGS plans to repeat the collar-cam research in 2015, he said.

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

Zak Smith is an attorney for the Marine Mammal Protection Project at NRDC. This Op-Ed is adapted from one that first appeared on the NRDC blog Switchboard. Smith contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

Most people don't know that Canada is the only country where polar bears are still hunted and killed to supply the world trade in polar bear skins and other parts (teeth, claws, skulls, etc.). But Canada's practice of allowing polar bears to be killed for profit when their very existence is threatened by climate change is now going to be scrutinized by the international community, which is expressing concern that such trade is not sustainable.

This critical issue came into focus at a meeting I recently attended in Veracruz, Mexico, of the Convention on International Trade in Endangered Species (CITES) — the international organization tasked with managing trade in endangered species.

The proposal to review Canada's trade in polar bear parts came at the urging of the United Kingdom and Norway, both of which raised questions as to whether the killing of polar bears from vulnerable populations may be detrimental to the species. Their concerns are well founded. The European Union already bans imports from two Canadian polar bear populations (Kane Basin and Baffin Bay) — believing that Canada's management of these populations is unsustainable — and the United States' listing of polar bears under the Endangered Species Act in 2008 bans all commercial and trophy imports from Canada into the United States.

In the review, Canada will have to show two things. First, how the killing of polar bears for profit is not harming threatened polar bear populations. And second, that the nation controls exports in a way that maintains polar bears throughout their range at levels consistent with their role in the ecosystem. But, with climate change impacts bearing down on vulnerable populations, paired with rising demand and prices, it will be difficult for Canada to justify trading polar bear parts. Canada's own experts have questioned whether Canada's management can withstand scrutiny. Andrew Derocher of the University of Alberta, a leading polar bear scientist, stated in February of this year that Canada's management is out of step with the rest of the world as hunter groups seek to increase harvest. He said, "There's very strong pressure across the Canadian populations to increase harvest levels," noting that, "[I]t is going to be a challenge to convince the international community that our science is strong enough to support these increases." [Is a Rhino Hunt Really Conservation? (Op-Ed )]

The international community's review procedure is designed to identify species that may be subject to unsustainable levels of international trade — as was done here in the case of polar bears — and to identify problems and solutions concerning effective management of trade. Recommendations can range from requiring the gathering of additional data (for example, many polar bear populations are "data deficient") to identifying specific export quotas to limit trade. Sometimes the process works and sometimes it doesn't. It can be unwieldy and disappointing. A lot depends on how aggressively the Animals Committee — the CITES committee that conducts the review — pushes back on self-serving submissions from states seeking to defend their management practices. Here for example, Canada's submission may be wanting. Canada's record on climate change has been rightfully criticized and reports continue to surface of territorial wildlife managers rejecting evidence that climate change is harming polar bears as they set quotas for how many polar bears can be killed.

It will be important for other polar bear states — like Norway, Russia and the United States —to push back on these kinds of unsubstantiated assertions and management decisions that veer from accepted conservation standards. Canada has a lot to answer for and the United States and Russia — strong advocates for polar bears at CITES — must continue pushing for greater polar bear protections through the review process, demanding that any trade is not detrimental to the survival of polar bear populations threatened with extinction from climate change.

Smith's most recent Op-Ed was "A Side of Dolphin with Your Shrimp Cocktail." This Op-Ed was adapted from the post "Serious Questions about Canada's Trade in Polar Bear Skins Trigger Review by International Body" on the NRDC blog Switchboard. Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google +. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

If humans ate the same fatty foods as polar bears, they would have heart attacks. But a new study reveals how these magnificent Arctic beasts survive on such a specialized diet.

It turns out the beasts have evolved genes that allow them to survive on a diet of mostly seals and the blubber those animals contain, not to mention their sky-high cholesterol levels, without developing heart disease.

The findings, detailed today (May 8) in the journal Cell, also showed that polar bears and brown bears diverged from each other much more recently than previously thought. [See Stunning Photos of a Polar Bear Expedition]

"In this limited amount of time, polar bears became uniquely adapted to the extremities of life out on the Arctic sea ice, enabling them to inhabit some of the world's harshest climates and most inhospitable conditions," study leader Rasmus Nielsen, a theoretical evolutionary biologist at the University of California, Berkeley, said in a statement.

In their study, Nielsen and his colleagues sequenced the complete genomes of 79 polar bears from Greenland and 10 brown bears from around the world. The researchers discovered that polar bears and brown bears branched off from a common ancestor sometime in the last 500,000 years, compared with previous data that suggested the two species diverged up to 5 million years ago.

Since splitting off from brown bears, polar bears have evolved quickly through mutations in genes that play roles in heart function and the metabolism of fatty acids, the study found. These same genes have been linked to human heart disease

The dramatic genetic changes in response to a fatty diet have not been reported before, suggesting that scientists should look beyond standard model organisms in studying the genetic causes of human heart disease, the researchers said.

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

Geoff York is head of Species Conservation for WWF's Global Arctic Program. He contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

There are only rolling swells on my last morning aboard this icebreaker as I enjoy breakfast at sea — a pleasant calm after a night of stormy turbulence. Over the past week, our craft has moved regularly among Svalbard's protected fjords and plowed through relatively thin ice, making for smooth sailing and easy sleeping. Once we turned south and headed out in the open Atlantic, though, it has not been so easy.

As we approach the southwestern shores of Spitsbergen, I survey the spectacular rugged mountains covered in snow and the glaciers reaching all the way to the contrasting dark ocean. Although I have enjoyed this view for the last 10 days, the scenery still takes my breath away.

I feel satisfied with the research accomplished on the voyage, but I can't help feeling a bit troubled about what we've observed. We came here in search of polar bears , expecting to encounter females with their cubs emerging from birthing dens and solitary male bears out hunting on the sea ice. Our research partners at the Norwegian Polar Institute (NPI) gathered data on 53 bears total, including seven females that are already transmitting from their new satellite collars.

However, our team found far fewer females with cubs than expected, along with several adult bears whose bodies were in poor condition. The researchers also found a dramatic lack of sea ice. The ice they did find had formed too recently to be of much use to bears or their primary food source, seals.

When we arrived, our Norwegian colleagues informed us that the ice conditions this year were so poor we would have to change our itinerary; we would need to head north where there was better ice if we hoped to see many bears.

Only 20 years ago, during the low-ice/summer season, a ship would have struggled to navigate the coast of Svalbard because of the sea ice. Today, the west coast of Svalbard is ice-free — even in winter. Areas in northern Svalbard have also changed, with fjords remaining unfrozen. Where there is ice, it is so thin that researchers cannot work there without the risk of falling through, into the water. This doesn't bode well for polar bears, who are inextricably tied to this frozen habitat. [Polar Bears on Thin Ice, Arctic Expedition Finds]

And the rapidly warming Arctic affects more than just polar bears. Ringed seals — polar bears' primary prey — are starting to show disturbing trends here as well. Changes in both the sea ice and in snow accumulation are harming the animals' reproductive ability, and failing to provide newborn pups with adequate protection from predators. While that may benefit bears in the short term, it will lead to long-term problems as ringed seal populations ultimately decline in number and potentially move to different locations. These same changes in the timing and extent of sea ice formation and snowfall will affect bear denning and seasonal movements, as well.

This research expedition aimed, in part, to look for polar bear denning sites and the distribution of family groups with new cubs, as early analysis of den data suggests a potential shift away from traditional denning areas. The researchers are pioneering work using geolocation ear tags that may help track movements and determine when bears go into dens. The dime-sized device records and stores a surprising amount of information on location, outside temperature and the amount of light.

Bears need to be close to sea ice when they emerge from dens so that they can hunt ringed seals found at the ice. During the last few years on southern islands, however, mothers and cubs emerged from the den in spring and found a totally open sea. The ice was already gone, and with it, most ringed seals, leaving the bears with a tough start to their new lives.

It's also become increasingly difficult for females to reach preferred denning areas. The winter-freezing period of sea ice — when the ice is at its greatest extent — has become increasingly delayed in recent years. Bears are ready to come ashore to den, but the ice edge ends up being too far away from land for the animals to make the trip. Do these females just den elsewhere, and what is their success rate? These are questions we hope NPI can answer in coming years.

The changes could certainly have an effect on polar-bear reproduction, but we really need better long-term monitoring to learn the overall impacts on populations. Even in the past, when conditions in the Arctic were more stable, there were always good and bad years for polar bears. Our challenge as scientists is to separate the short-term variation — what we would consider natural fluctuations — from significant, long-term trends. Then we need to combine this data on long-term trends with the best available projections on climate and sea ice. This will help to predict how polar bears will respond to the expected loss of their sea ice habitat in the coming years — no easy task for scientists.

Monitoring wildlife takes time, financial investment and a lot of manpower. Studying polar bears presents even greater challenges: remote and largely inaccessible habitat for much of the year; field conditions hostile to humans and equipment; and the animals' broad, circumpolar distribution. Despite such obstacles, data gathered on this trip and in the coming year from satellites will add considerably to the understanding of polar bears in this remote Arctic area.

Author's Note: You can track the bears and learn more about the expedition at this site.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.

Polar Bear on the Ice

In April, World Wildlife Fund (WWF), the Norwegian Polar Institute (NPI) and Canon photographers spent nearly two weeks on a research expedition to the islands of Arctic Norway. A former U.S. Coast Guard icebreaker ship served as their research vessel. Through aerial surveys and on-the-ground fieldwork, the team searched for polar bears on the ice and any females emerging from denning sites. The team collected biological samples as well, to learn more about the how the bears are doing. They also paid close attention to the sea-ice conditions, as sea ice is critical habitat for bears and their primary prey, seals. The following photos reveal the stunning scenery and realities of fieldwork in the harsh Arctic environment, and some of the initial findings from the expedition. [ Polar Bear Monitoring More Crucial as Ice Dwindles (Op-Ed)]

Pancake Ice Near Monaco Glacier

Chunks of sea ice — called pancake ice — litter the waters near Monaco glacier. During the sea-ice formation process, these chunks of ice would normally join together to eventually form ice sheets. Water temperatures, however, are not cold enough to allow ice to grow thick and solid, even though air temps are well below zero. The team was surprised by how little sea ice there was in the waters around Svalbard. Sea ice extent and thickness has changed a lot over the last couple decades, with more and more areas completely ice-free all the time. For one researcher, this was the least amount of ice he’d seen in the past eleven years.

Breaking the Ice

A member of the Svalbard expedition uses a rubber sledge hammer to knock off ice that is blanketing the icebreaker research vessel, the Lance. Such ship-keeping comes with the territory, this high in the Arctic. Frozen seawater covered every exposed surface in the frigid air. The researchers and crew had to wear helmets while on deck to protect themselves from falling icicles.

polar bear tagging expedition

A researcher fits a sedated polar bear with an ear tag. The Norwegian Polar Institute is pioneering work using geo-location ear tags that may help determine when bears go into dens. The dime-sized device records and stores a surprising amount of information on location, outside temperature and the amount of light. Such tags are one example of the exciting new technology being used in wildlife research.

Svalbard Research Team in Helicopter

The Svalbard research team heads out in a helicopter to conduct aerial surveys. The helicopter went out every day, as weather permitted, in search of bears on sea ice — where the team could find it, as there was far less this year than on previous surveys. The researchers were also looking for places where females were coming out of dens and trying to find family groups. If able, the team tried to capture the bears to assess their health, measure their size and fit them with satellite collars. Only females receive collars, as collars slip off the smaller necks of males and cubs. During the ten-day research cruise, there were not many females observed with cubs or yearlings, which is concerning. Sea ice is critical habitat for polar bears and their primary prey, ringed seals, and the lack of sea ice is already negatively impacting seal reproduction.

Polar Bear Prints

The crew found a trail of polar bear prints near where the ship was stationed. Samples of snow from the prints were collected to test out an innovative new genetic technique — collecting usable DNA from where polar bears have tread. This is being piloted in Norway and in the United States, in collaboration with a French genetics lab that has shown this is possible with other species. If it works, this technique has promising implications for research in more remote parts of the Arctic, where there is a lack of basic information on bears and lack of capacity for monitoring.

Ice on the Deck of the Lance

A clear sunny day reveals Svalbard’s spectacular rugged mountains covered in snow and the gentle glaciers which reach all the way to the sea. Frozen seawater covers all of the exposed surfaces of the Lance giving it a haunting look. The night before had been a rough one at sea, with water splashing over the ship as it crashed down between the waves.

A Polar Bear Paw

While humans rely on ice picks to navigate glaciers, polar bears are naturally equipped. Each nearly 12-inch paw has five sharp and strong claws, which are also perfectly designed for catching and holding seals. The paws are also very broad, and this helps the bear spread out more of its weight on thin sea ice to avoid breaking through.

Weighing a Polar Bear

Balancing a field scale on their shoulders, researchers weigh a sedated polar bear cradled in a sling. Bears can weigh between 350 pounds and 1,200 pounds, with males being larger than females. The team also measures bear length and estimate's each animal's age. They also collect samples of blood, fat, hair and other tissues. These samples are processed back on the ship, and will be analyzed in the coming year. Learn more about the expedition and tack the bears here.

Spotting Polar Bears

A polar bear is spotted from a helicopter’s aerial survey. Polar bears are well-camouflaged in this world of snow and ice, which is advantage if you are a predator and want to catch seals. Nonetheless, the research team was able to find 53 bears this season, and fitted 7 females with satellite collars during the cruise.

An expedition to the islands of Svalbard, Norway, to study how rising temperatures and melting sea ice are affecting polar bears concluded Monday (April 21).

Over the 10-day trek, researchers outfitted female bears with satellite tracking collars that will send back data, giving researchers a picture of how shrinking sea ice may be affecting the polar bears' movements and denning patterns.

"The bear denning habitats appear to be shifting further north," Geoff York, one of the expedition leaders, told Live Science via satellite phone from the team's ship in Svalbard Thursday (April 17). The team had so far deployed 11 of their 20 collars, York said. [Gallery: Polar Bears Swimming in the Arctic Ocean]

The 2013-2014 winter has seen record-low levels of sea ice — which the bears rely on to hunt — around Svalbard, said York, who is a polar bear researcher at the World Wildlife Fund. "The question is how the bears will respond as there's less and less sea ice."

Researchers at the Norwegian Polar Institute have been monitoring the polar bears in Svalbard for years using tracking collars. This year, the WWF and camera maker Canon joined the effort, allowing the team to stay longer and put out more collars.

The satellite data suggest there are two groups of bears: Those on the northern end of the archipelago mostly keep to the open water and sea ice, rarely coming onshore. Other bears stay mainly onshore in summertime, hardly ever leaving the islands.

One thing the researchers don't know is exactly how many bears there are, York said. Researchers estimate there may be about 2,600, plus or minus a few hundred.

Capturing a polar bear for tagging is no easy feat. A crew aboard a helicopter locates a bear and darts it with a sedative from the air. On the ground, the team measures the bear's length and weight, and takes blood and hair samples. The researchers only put collars on the adult females — the heads of male bears and cubs are smaller than their necks, so the collars don't stay on them.

"All of the movement data is from adult female bears," York said. "We have very little data on cubs and males."

The collars have sensors that record temperature, daylight, immersion in saltwater and depth. They tell researchers how much time the bears spend in the dens, and how often they go into the ocean to hunt.

The bears primarily eat ringed seal, but they also eat bearded seals, young walruses and sometimes even beluga whales or narwhal, though more often, they eat whale carcasses, York said. Polar bears have also been known to cannibalize other bears, and male bears have been documented committing infanticide for food.

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

Today is International Polar Bear Day, which celebrates everyone's favorite furry beasts of the Arctic. In honor of the occasion, Live Science brings you some wacky facts about the furry beasts.

1. Males can weigh as much as a dozen men

An adult male polar bear typically weighs between 775 and 1,200 pounds (351 to 544 kilograms), or the weight of about five to seven men. The largest polar bear ever recorded was a male weighing 2,209 pounds (1,000 kg), according to Polar Bear International. By contrast, adult females weigh only half as much as males, or 330 to 650 pounds (50 to 295 kg).

But the bears are tiny when they're born, weighing only about 1 pound (0.5 kg). Males reach their adult size between ages 8 and 14, while females reach full size between ages 5 and 6. [Photos of Polar Bears Swimming in the Arctic]

2. They can go days without eating

If a polar bear doesn't eat for seven to 10 days, it can slow its metabolism until it finds its next meal. They survive off of fat reserves from their diet, which consists mostly of ringed and bearded seals. (But climate change is making food more scarce and driving some bears to cannibalism.)

The bears don't hibernate, but mother bears live in dens while they raise their cubs. While mama bears are in their dens (generally between January and March), they don't eat, drink or defecate.

3. Polar bears sport see-through fur

Although polar bears appear white, their fur is actually transparent. It only appears white, because it reflects visible light. Under their fur, polar bear skin is actually black.

To humans and other animals that can see only in visible light, the bears appear to blend in with their snowy surroundings. But reindeer, which polar bears sometimes prey on, can see in ultraviolet light, which makes polar bears stand out from their snowy environment.

4. They have a razor-sharp sense of smell

Polar bears have a keen sense of smell, which they use to find prey. A polar bear can sniff out a seal on the ice 20 miles (32 kilometers) away, and can smell a seal's breathing hole in the ice more than half a mile away, according to the National Zoo.

5. Two-thirds of polar bears could disappear by 2050

Polar bears rely on sea ice to hunt, and studies predict that global warming could melt enough sea ice to lead to the disappearance of two-thirds of polar bears by 2050. The decline in sea ice has forced the bears to swim longer distances, consuming energy they cannot afford to use.

The United States listed polar bears as a threatened species under the Endangered Species Act in May 2008, and Canada and Russia have listed them as a species of special concern. Unless climate change slows, eventually there may not be any bears around to celebrate Polar Bear Day.

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