A polar bear from southeast Greenland on ice from a glacier or freshwater at 61 degrees north in September 2016.Picture: Thomas W. Johansen / NASA Oceans Melting Greenland
Researchers have identified a previously unknown polar bear population that lives in isolation in southeastern Greenland. Bears hunt seals in the fjords, on the platforms of freshwater ice, instead of the rapidly retreating sea ice like other polar bear species.
A new report in the journal Science describes the population, which now brings the total number of known polar bear groups from 19 to 20. Scientists were aware that some polar bears may be in this area according to historical records and knowledge of the indigenous communities of the Arctic, and were finally able to confirm that this is a separate population. The group consists of a few hundred bears, and females are usually smaller than those in other populations.
“The polar bears in SE Greenland are the most genetically isolated polar bears on the planet. They differ from the other 19 polar bear subpopulations in the Arctic and diverge more from neighboring subpopulations than any other pair,” said Kristin Laidre. , a polar scientist at the University of Washington and lead author of the study, in an email to Earther. “They’ve been separated for a few hundred years, and they’ve probably always been a small population.”
Scientists worked for years to establish research sites in Greenland, collar bears and control them to confirm their adaptability and isolation. Laidre said this new group was tracked from 2015 to 2021.
Three adult polar bears in southeastern Greenland in April 2015. They are using sea ice for a limited time when it is available.Picture: Kristin Laidre / University of Washington
Elizabeth Peacock, an assistant professor at Emory University School of Medicine and an expert on polar bears, wrote a perspective paper to accompany Laidre’s research in the journal Science. He explained that some online posts have hinted that this group of isolated bears could be a “prosperous” population because they have found a new way to hunt. But Peacock is not sure.
“Plasticity usually refers to a person who has 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,'” he said. natural is about adapting over time … that means polar bears have enough time to change what they are doing to respond to natural selection. “
Unfortunately, the effects of climate change are occurring faster than many polar bears can reproduce.
The points on the left map show the locations where samples of the polar bears from Greenland were collected. The new population in southeast Greenland, shown as red dots, is between 60 and 64 degrees north. Image: Laidre et al./Science
In his article, Peacock pointed to other known polar bear populations that have shown signs of plasticity, such as nesting further in the sea ice depletion or hunting for different types of prey when their usual diet of seals is not so abundant. There are questions about whether glacier hunting will continue to be possible in the future, as the ice melts at both poles. Generations of polar bears last about 10 years, but climate change is affecting ice at a much faster rate than that. Researchers are concerned that this new behavior will not be transmitted, because the climate crisis is rapidly depleting the Arctic ice.
“We don’t have an IDEA if they’re thriving. We don’t know if the population is stable or in trouble. That will require more research,” Laidre said in an email. To really determine how this population copes with climate change, scientists will have to study the survival of adult polar bear females by marking and studying them for three to four years.
“Glacier ice can help a small number of polar bears survive for longer periods under global warming and can be important for the species’ persistence (i.e., prevention of extinction).” but it is not available to the vast majority of polar bears, “he said. “Future monitoring of these bears may tell us a little more about the future of the species.”