December 8, 2022

The discovery of a strange and isolated group of polar bears in Greenland

The discovery of a strange and isolated group of polar bears in Greenland

A polar bear in southeast Greenland on ice, or freshwater, on ice at 61°N in September 2016.

A polar bear in southeast Greenland on ice, or freshwater, on ice at 61°N in September 2016.
picture: Thomas W. Johansen/NASA Greenland’s oceans are melting

Researchers have identified a previously unknown group of polar bears that live in isolation in southeastern Greenland. Bears hunt seals in fjords, on icy freshwater cliffs, rather than the rapidly retreating sea ice like other polar bear species.

New report in the magazine Sciences describes the population, which now raises the total number of known populations of polar bears from 19 to 20. Scientists were aware that some polar bears could be in this area based on historical records and knowledge from indigenous communities in the Arctic, and were finally able to confirm that these A separate group of people. group consists Of a few hundred bears, the females tend to be smaller than those in other populations.

“Polar bears in southeastern Greenland are the most genetically isolated polar bears on the planet. They differ from all of the other 19 polar bear subpopulations in the polar region,” said Kristin Lieder, a polar scientist at the University of Washington and lead author of the study, in an email to Earther. Northern and more divergent from neighboring subpopulations than any other pair.“They separated a few hundred years ago, and are likely always a small population.”

Scientists have worked for years to establish research centers in Greenland, collar the bears, and monitor them for their adaptability and isolation. This new group was tracked from 2015 to 2021, Leader said.

Three adult polar bears in southeast Greenland in April 2015. They use sea ice during the limited time when it is available.

Three adult polar bears in southeast Greenland in April 2015. They use sea ice during the limited time when it is available.
picture: Kristen Leader/University of Washington

Elizabeth Peacock, an assistant professor at Emory University School of Medicine and a polar bear expert, wrote a perspective article to accompany Lidri’s research in the journal Science. She explained that some online posts had hinted that this isolated group of bears could be a “thriving” group because they had found a new way to hunt. But Peacock is not sure that is the case.

She said, “Plasticity generally refers to an individual having the ability, you know, to use different behaviors…so, ‘I can figure out how to kill a walrus or I can figure out how to catch fish.’” Natural selection is about adapting over time… which assumes that polar bears have enough time to change what they do in response to natural selection.”

Unfortunately, the effects of Climate change They occur faster than many polar bears are able to reproduce.

Points on the left map indicate locations where samples of polar bears have been collected in Greenland.  The population of Southeast New Greenland, as indicated by the red dots, is located between 60 and 64 degrees north latitude.

Points on the left map indicate locations where samples of polar bears have been collected in Greenland. The population of Southeast New Greenland, as indicated by the red dots, is located between 60 and 64 degrees north latitude.
picture: Lidri et al. / Sciences

In her article, Peacock referenced other known polar bear populations that have shown signs of plasticity, such as nesting far inland away from depleting sea ice or foraging for different types of prey when their usual diet is not plentiful. There are questions about whether glacier fishing will continue in the future, as the ice at both poles melts. Polar bear generations are about 10 yearsBut climate change is affecting ice at a much faster rate than that. Researchers are concerned that this new behavior may not be inherited, because the climate crisis is rapidly depleting ice in the Arctic.

“We have no idea if they’re thriving. We don’t know if the population is stable or in trouble. This will require more research,” Lieder said in an email. To determine how this group performs in the face of climate change, scientists will have to study The survival of female polar bears through identification and study over a period of three or four years.

“Ice ice may help small numbers of polar bears survive for longer periods in a warming climate, and may be important to species continuity (meaning preventing extinction), but is not available to the vast majority of polar bears,” she said. “Future observation of these bears could tell us a little more about the future of the species.”