Residents and RCMP in Deline, N.W.T., described the three polar bears that wandered into their community April 2 as being thin and hungry. ((Photo courtesy Les Baton))

Polar bears in the southern Beaufort Sea are starving as they struggle to adapt to a warming Arctic climate, according to the latest research by a Canadian polar bear expert.

Changing spring sea ice is making it more difficult for the bears to hunt their primary prey, the ringed seal, said Ian Stirling of the Canadian Wildlife Service.

In an article published in the March issue of Arctic, the journal of the Arctic Institute of North America, Stirling documents finding three bears starving to death on the Beaufort Sea ice.

He told CBC News that he also found bears resorting to extreme measures to stay alive.

"We found four different incidents where the bear had been killed by an adult male to eat — in other words, cannibalism," Stirling said Wednesday.

"I thought that was very unusual. I've never seen it, anywhere."

Ringed seals usually make homes of snow on the large, smooth expanses of sea ice during the spring. But Stirling's research has found that global warming has caused thin ice to layer and bunch together to create ice formations in which seals can hide.

Those new hiding places have meant that the bears must claw through thick layers of ice to get to the seals, he added.

Bears may not survive wandering inland

Stirling said hunger has also likely driven some polar bears to leave the Arctic Ocean and wander hundreds of kilometres south — as was the case last week, when a mother bear and two cubs arrived in Déline, N.W.T., about 400 kilometres south of their usual habitat.

"The cubs were leading their Mom. It looks like they were pretty hungry," said Walter Bayha, one of about 100 Déline residents who saw the trio of polar bears in the community on April 2. RCMP shot and killed the bears out of safety concerns.

Stirling said that if the Beaufort Sea ice keeps changing, people should expect more polar bears to wander inland. However, he warns that polar bears will have a hard time surviving there.

"Some people say the bears, in terms of climate warming, will just adapt and go on to land. That's simply not going to happen," he said.

"There isn't enough food on the land to start with. And even if there was tonnes of berries, polar bears are too large to be able to maintain themselves on that kind of a diet."

The number of polar bears will also continue to decrease as long as the ice continues to change, he added.