The rapid melting of sea ice in the Arctic poses a threat to the survival of polar bears, which use it as a platform to hunt seals. But scientists have identified a new population of these animals in southeastern Greenland, which uses the boulders detaching from freshwater glaciers.
Their discovery, described in a study published Thursday, June 16, in the prestigious journal Scienceopens the possibility that at least a few representatives of this species could survive during the century, knowing that the Arctic sea ice should eventually completely disappear in summer.
A previously unidentified population of polar bears documented on the southeast coast of Greenland uses glacier ice… https://t.co/jtoa5z6SWm
“One of the big questions is where are the polar bears going to be able to stay?explained to Agence France-Presse (AFP), Kristin Laidre, professor and scientist at the University of Washington (State of Washington) and at the Greenland Institute of Natural Resources. I think bears in a place like this can tell us a lot about where this might be. »
A homebody temperament
She and her colleagues first spent two years interviewing Inuit hunters. Then they began their fieldwork, conducted between 2015 and 2021, in an understudied region due to its unpredictable weather, heavy snowfall and mountains. Each year, the researchers spent a month there, in the spring, staying as close as possible to where these polar bears live.
This population has a priori several hundred individuals. Bears have been fitted with satellite tracking devices, and DNA samples have been taken, either by capturing some of these animals or by using darts to sedate them for biopsies.
“This is the most genetically isolated population of polar bears on the planet.according to Beth Shapiro, co-author of the study and geneticist at the University of California, Santa Cruz. We know that this population lived separately from other polar bears for at least several hundred years. »
Unlike their cousins, these polar bears tend to be homebodies, and don’t go far to hunt. Their isolation is explained by the fact of their place of life: a territory of fjords on the southern tip of Greenland, well below the Arctic Circle, with nowhere to go. To the west rise impressive mountains, and to the east unfold the waters of the Denmark Strait, with a rapid current along the coasts in a southerly direction.
“When they get swept away by this current, they jump off the ice and walk back to their fjords”, explained Kristin Laidre. According to the researchers, some bears had to travel more than 150 kilometers to return home.
Act fast to save polar bears
While the pack ice – made up of seawater – provides an ideal hunting platform for most of the approximately 26,000 polar bears in the Arctic, it is only formed for four months – between February and the end of May. – in this part of southeastern Greenland. The rest of the year, these animals rely on chunks of freshwater ice, breaking off from glaciers and ending up directly in the sea.
“The combination of fjords, high ice production, and the large reservoir of ice from the Greenland Ice Sheet, is what currently provides a continuous supply of ice”explained in a press release Twila Moon, co-author of the study.
There are still many studies to be done on polar bears in this part of Greenland. Measurements have shown that adult females are somewhat smaller than average, and they seem to have fewer young. But it is difficult to draw conclusions in the absence of long-term data.
Kristin Laidre warns that we must beware of placing too many hopes in this study. Polar bears – iconic animals in their own right, but also a precious resource for the people of the region – will not be saved without urgent action to combat climate change. But this population may have a better chance of survival than the others. Other parts of Greenland have glaciers flowing directly into the sea; they could, in the future, become small climatic refuges.