Polar bears usually want sea ice to hunt seals, however an remoted group of polar bears dwelling on the rugged, mountainous coast of southeast Greenland have discovered methods to eke out a dwelling, although the ocean ice there melts away early within the 12 months.
These bears have discovered a solution to complement their restricted sea ice provide by searching on freshwater ice that comes from glaciers on land. The glacial ice falls off in chunks into fjords, the place the items glom collectively right into a jumbled, floating platform that the polar bears use to stalk seals, in accordance with a report within the journal Science.
Local weather change is making sea ice an increasing number of scarce. Lack of sea ice is “the first risk to polar bears,” says Kristin Laidre of the College of Washington, the lead writer of the brand new examine. However, she says, this new work suggests some bears would possibly have the ability to address a diminished quantity of sea ice — not less than for awhile — in locations the place they’ll reap the benefits of floating glacier ice, like Greenland and Svalbard, an archipelago within the Arctic Ocean.
“Glacial ice principally would possibly assist small numbers of bears survive for longer intervals beneath local weather warming,” she says.
Bears discover a approach
Whereas indigenous individuals have lengthy recognized that that bears lived in southeast Greenland, it is a distant, difficult setting that is not frequented by people. “It is a shoreline with enormous mountain peaks, numerous winds, excessive circumstances, numerous fog,” says Laidre, who has spent years working with colleagues to survey polar bears dwelling on Greenland’s 1,800-mile-long east coast.
To see what they may discover within the southeast, the group needed to take helicopters from the closest settlement and fly for 2 hours in a straight line to the coast. “We arrived in these fjords, very remoted fjords, and there is basically no sea ice or very poor sea ice off shore,” says Laidre, explaining that the researchers anticipated to search out few bears.
“However there have been a number of bears in these fjords,” she says. “It was clearly only a distinctive habitat.”
The ocean ice continued in these fjords for under round 100 days a 12 months, she notes, which means that bears haven’t got a lot time to make use of it as a searching floor. “It disappears in Might, and that is actually early,” says Laidre. “It isn’t sufficient time for a polar bear to get fats sufficient and survive.”
However the geography of this space makes it in order that glaciers pour freshwater ice down over the mountains and into the fjords, she says. Icebergs break off from the glacier and congeal into an irregular floor that the polar bears can use as a platform for seal searching. “They complement their searching time through the use of this freshwater ice,” says Laidre.
When it was secure to land their helicopter, the researchers would briefly seize bears to take genetic samples or placed on location trackers. “We might gather info on their actions, their physique situation, their well being, their genetics,” says Laidre.
A tightknit clan
She estimates that not less than few hundred polar bears dwell in southeast Greenland, and it seems that they are probably the most genetically remoted polar bears on the planet. They’re distinct from all different 19 polar bear subpopulations that scientists at present acknowledge within the Arctic.
Which may be as a result of these bears are homebodies. The entire tracked bears just about stayed of their dwelling fjord or fjords. Sometimes, the bears obtained caught by a quick sea present that rips down the coast in direction of southern tip of Greenland, says Laidre, however the bears would rapidly swim to shore. “After which they’d stroll dwelling over the ice sheet to get again to their fjord.”
“The discovering of a possible new subpopulation in southeast Greenland is absolutely attention-grabbing,” says Todd Atwood, a polar bear researcher on the U.S. Geological Survey Alaska Science Heart in Anchorage. He thinks the bears’ genetics, patterns of motion, and searching habits “makes a fairly compelling case” that that is certainly a definite subpopulation.
The way in which that these bears hunt utilizing freshwater ice “would possibly purchase bears in that space somewhat bit extra time, as pack ice continues to say no, as a result of they aren’t solely reliant on the pack ice,” says Atwood.
However most polar bears are fully depending on the ocean staying frozen for a very long time annually, says Atwood, including that analysis means that greater than 180 days of ice-free circumstances ends in steep declines in polar bear populations, because the bears cannot eat sufficient seals to outlive and reproduce.
“The bears themselves have a primary job to perform. They have to be on the ice for lengthy sufficient to have the ability to kill sufficient seals to retailer sufficient fats to dwell for a 12 months,” says Ian Stirling, a polar bear biologist on the College of Alberta.
The uncommon areas the place polar bears have entry to glacier ice, like southeast Greenland, will not function a possible refuge from local weather change ceaselessly, says Stirling.
“If the local weather continues to heat because it’s projected to do, these areas too will turn out to be of no use or not sufficient use to the bears,” says Stirling, noting that ultimately the ends of the glaciers will soften away till they’ve retreated up on the land somewhat than extending out into the water. By that point that occurs, he says, a lot ice may have disappeared that “the bears shall be lengthy gone.”