Greenland polar bears learn to hunt glacier ice: NPR


A female bear and two 1-year-old cubs walk on the snow-covered freshwater glacier ice of Southeast Greenland.

Kristin Laidre


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Kristin Laidre


A female bear and two 1-year-old cubs walk on the snow-covered freshwater glacier ice of Southeast Greenland.

Kristin Laidre

Polar bears often need sea ice to hunt seals, but an isolated group of polar bears living on the rugged, mountainous coast of southeastern Greenland have figured out how to make a living, despite the ice. sea ​​there melted early in the year.

These bears have found a way to supplement their limited supply of sea ice by hunting for flat ice that comes from land glaciers. Glacial ice is crashing into fragments into fjords, where the fragments shine on a floating, floating platform used by polar bears to stalk seals, according to a journal report. Science.

Climate change is making sea ice less frequent. The loss of sea ice is “the main threat to polar bears,” it says Kristin Laidre at the University of Washington, was the lead author of the new study. But, he said, this new work suggests that some bears may be able to cope with a decrease in the amount of sea ice – at least for a while – in areas where they can take advantage of floating glacier ice, such as Greenland and Svalbard, an island in the Arctic Sea.

“Ice ice will primarily help small numbers of bears survive longer periods under warming climates,” he said.

The bears are looking for a way

While the natives have long known that those bears live in southeastern Greenland, it is a remote, challenging environment that is not often visited by humans. “It’s a beach with great mountain peaks, lots of wind, severe conditions, lots of fog,” said Laidre, who has worked with colleagues to survey polar bears that live 1,800-miles for many years. the length of the east coast of Greenland.


A fjord in Southeast Greenland, shown with marine-terminating glaciers in the distance. Polar bears here survive by hunting in the shallow ice water that flows into the sea from glaciers.

Kristin Laidre


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Kristin Laidre


A fjord in Southeast Greenland, shown with marine-terminating glaciers in the distance. Polar bears here survive by hunting in the shallow ice water that flows into the sea from glaciers.

Kristin Laidre

To see what they could find in the southeast, the team had to pick up helicopters from the nearest shelter and fly for two hours in a straight line to the coast. “We came to these fjords, very remote fjords, and there was no sea ice or bad sea ice on the coast,” Laidre said, explaining that the researchers were expecting to find some bears.

“But there are a lot of bears in these fjords,” he said. “It’s clearly just a unique residence.”

Sea ice persists in these fjords for only a hundred days a year, he said, which means bears don’t have much time to use it as a hunting ground. “It disappeared in May, and that was early,” Laidre said. “Not enough time for a polar bear to grow fat and survive.”

But the geography of this area makes it so that glaciers for flat water ice under the mountains and into the fjords, he said. Icebergs break from the glacier and collapse into an irregular surface that polar bears can use as a hunting platform and seals. “They increase their hunting time by using this freshwater ice,” Laidre said.

When it was safe to land their helicopter, the researchers would catch the short bears to take genetic samples or place them on location trackers. “We collect information on their movements, on their physical condition, on their health, on their genetics,” Laidre said.

A tight clan

He estimates that at least a few hundred polar bears live in southeastern Greenland, and it is the most genetically isolated polar bear on the planet. They are different from the other 19 polar bear subpopulations now identified by Arctic scientists.

That’s probably because these bears are homebodies. All tracked bears remain in their fjord or fjord home. Sometimes, bears are caught in strong sea currents that flood the coast toward the southern tip of Greenland, Laidre said, but the bears swim immediately toward shore. “And then they walk back over the ice sheet to get back to their fjord.”

“Finding a potential new subpopulation in south-east Greenland is very interesting,” he said. Todd Atwood, a polar bear researcher at the U.S. Geological Survey Alaska Science Center in Anchorage. He thinks the bears ’genetics, movement patterns, and hunting habits“ make a compelling case ”that they are a distinct subpopulation.

The way these bears are hunted using freshwater ice “can buy bears in the area in less time, because pack ice continues to decline, because they don’t just rely on pack ice,” Atwood said. .

But most polar bears rely entirely on the sea that stays frozen for long periods of time each year, according to Atwood, adding that research suggests more than 180 days of ice-free conditions. result in a severe reduction in the polar bear population, as can bears. do not eat enough seals to survive and reproduce.

“The bears themselves have a basic job to do. They have to be on the ice for a long time to kill enough seals to store enough fat to survive a year,” he said. Ian Stirlinga polar bear biologist at the University of Alberta.

Unique areas where polar bears have access to glacier ice, such as southeastern Greenland, will not serve as potential refuge from climate change forever, according to Stirling.

“If the climate continues to warm as planned to do, these areas will also become useless or inadequate for bears,” Stirling said, noting that eventually the ends of glaciers melt until they retreat. on the ground instead of reaching into the water. By the time that happens, he said, so much ice will have disappeared that “the bears will be gone for a long time.”

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