Researchershave discovered a unique group of polar bears who’ve survived in the -组卷网

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Researchers have discovered a unique group of polar bears who’ve survived in the absence of sea ice: by hunting from the ice that breaks off glaciers (冰川). The bears live in southeast Greenland and are a genetically(基因地) distinct subpopulation, which suggests they’ve been separated from other polar bears for around 200 years, according to a paper published this week in Science.

“The findings show us how some polar bears might survive under climate change. but I don’t think glacier habitat is going to support huge numbers of polar bears,” said Kristin Laidre, a polar research scientist at the University of Washington. “There’s just not enough of it. We still expect to see large declines in polar bears across the Arctic under climate change.”

When temporary ice sheets form on the ocean during each fall’s freeze, the bears walk across it in search of food, often by sitting next to gaps in the ice and waiting for seals to come up for air. When the ice melts (融化) in spring, polar bears typically survive between 100 and 180 days without food until the ice forms again. As temperatures rise, however, that period is becoming longer, which is harming the bears and pushing them toward starvation. The bears living in southeast Greenland go even longer without sea ice—around 250 days. But they’ve been able to continue bunting during that period by using large pieces of ice that break off from glaciers into the water.

There are roughly 26, 000 polar bears remaining across the globe. Though the southeast Greenland bears have adapted to surviving in their surroundings, rising temperatures may ultimately cause their glacial ice to shrink, too. As Steve Armstrup, a scientist with Polar Bears International says, the study “is not some kind of effective rescue for polar bears”. While the southeast Greenland bears are able to hunt through glacial ice today, he says, “In the future, that will change unless we arrest the rise of global greenhouse gases.”

【小题1】What do we know about the newly- found polar bears?