“Polar bears have been getting fatter even as sea ice disappears in Norway’s Svalbard archipelago, the fastest-warming place on Earth…

The average size and weight of the Svalbard bears have increased since 2000, a finding that surprised Jon Aars at the Norwegian Polar Institute, who led the study…

The Barents Sea population, which was estimated at 1900 to 3600 bears two decades ago, is thought to be stable or perhaps even growing. Starting in 1995, Aars and his colleagues tranquilised 770 bears with dart guns from helicopters. They hopped out onto the snow or ice to measure their length and, to estimate weight, their girth at the chest.

Trend analysis showed this body condition decreased until 2000, then increased until the end of observations in 2019.

In the spring, when ringed seals give birth to pups on the sea ice, polar bears hunt them to build up stores of fat for the ice-free months. Aars and his colleagues believe the shrinking ice area may be making these seals easier to find.

The bears are also exploiting new food sources. The approximately 250 individuals that remain on the islands when the ice recedes may be hunting more bearded seals along the coast, as well as harbour seals, which are spreading to Svalbard as the climate warms.

These ‘local bears’ are increasingly ransacking duck and geese colonies for eggs, and they have been seen chasing down reindeer from a growing cervid population. The carcasses of walruses, another species that is increasing there, can provide weeks of feasting.”

From New Scientist.