(Washington) The rapid melting of sea ice in the Arctic poses a serious threat to the survival of polar bears, who use it as a platform to hunt seals.
Published at 4:38 pm.
But scientists have identified a new population of polar bears in southeastern Greenland that uses chunks of ice that break off from the region’s freshwater glaciers.
Their discovery, described in a study published Thursday in the prestigious journal Scienceopens the possibility that at least some representatives of this species could survive during the century, knowing that the Arctic sea ice must eventually disappear completely in the summer.
“One of the big questions is where the polar bears can stay,” Kristin Laidre, a scientist at the University of Washington and the Greenland Institute of Natural Resources, told AFP. “I think bears in a place like this can tell us a lot about where this might be. »
She and her colleagues spent two years interviewing Inuit hunters. Then, they started the fieldwork, carried out between 2015 and 2021, in a region little studied due to unpredictable weather, heavy snowfall and mountains.
Each year, the researchers spent a month there, in the spring, getting as close as possible to where these polar bears live, two hours away by helicopter. Fuel reserves had to be placed on the road ahead of time.
This population has a priori several hundred individuals. The bears were equipped with satellite tracking devices and DNA samples were taken, capturing some of them or using darts to take biopsies.
“This is the most genetically isolated polar bear population on the planet,” said Beth Shapiro, study co-author 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 are more homely and don’t go very far to hunt.
Their isolation stems from the geography of where they live: a complex landscape of fjords in the southern tip of Greenland, far below the Arctic Circle, with nowhere to go.
To the west, impressive mountains, and to the east, the waters of the Strait of Denmark, with a rapid current along the coasts, towards the south.
“When they find themselves carried 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.
While sea ice (sea water) provides a hunting platform for most of the Arctic’s roughly 26,000 polar bears, in southeastern Greenland polar bears only have access to it for four months. , between February and the end of May.
For the other eight months, they rely on chunks of freshwater ice that break off from glaciers and end up directly in the sea.
“The combination of fjords, high ice production and the large ice reservoir of the Greenland Ice Sheet is what currently provides a continuous supply of ice from glaciers,” Twila Moon, co-author, said in a statement. studying.
There is still a lot to be studied in the polar bears of this part of Greenland. Measurements showed that adult females are slightly smaller than average and appear to have fewer young. But it is difficult to draw conclusions in the absence of long-term data.
Kristin Laidre cautions that we must be careful not to pin too much hope on 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 others. And other regions of Greenland have glaciers that end directly in the sea, which could, in the future, become small climate refuges.