A large male polar bear with the remains of a cub he caught from a female polar bear and killed in the Churchill Wildlife Managment Area on Nov. 20. (Daniel J. Cox/NaturalExposures.com)The late formation of Arctic sea ice may be forcing some hungry and desperate polar bears in northern Manitoba to resort to cannibalism.

Eight cases of mature male polar bears eating bear cubs have been reported this year among the animals around Churchill, according to scientists.

Four cases were reported to Manitoba Conservation and four to Environment Canada.

Some tourists on a tundra buggy tour of the Churchill wildlife management area on Nov. 20 were shaken and started crying after witnessing a male bear eating a cub, said John Gunter, general manager for Frontiers North Adventures, an area tour operator.

"A big male polar bear separated a young cub from its mother and had its way with the cub," he said. "But the whole time, while that mother polar bear watched and witnessed, and actually after the big bears left, she still tried to take care of it.

"It was difficult for our guests to witness and it was difficult for me to hear about and learn about. It was a sombre day on the buggy that's for sure."

'It's a normal normal occurrence. '—Jose Kusugak,Kivalliq Inuit Association

In recent years, Manitoba Conservation has received one to two reports each year about bear cannibalism.

Retired Environment Canada biologist Ian Stirling, who has studied bears all over the arctic, said evidence suggests the cubs are being killed for food, not just so the male can mate with the sow. The Hudson Bay sea ice, which the bears use to get at the seals they need to fatten up for winter, isn't appearing until weeks later than it used to, he said.

However, an Inuit leader in Rankin Inlet, Nunavut said the incidents are non-events and that it's wrong to connect the bear's behaviour with starvation.

"It makes the south — southern people — look so ignorant," said Kivalliq Inuit Association president Jose Kusugak.

"A male polar bear eating a cub becomes a big story and they try to marry it with climate change and so on, it becomes absurd when it's a normal normal occurrence," Kusugak said.

Kusugak admitted some communities are having polar bear problems because warmer than average temperatures means sea ice hasn't yet formed properly.

But he disagrees that their numbers are dwindling or that polar bears are in other danger because of climate change.

Bears trying to survive longer on fat reserves, conservationists say

A male polar bear drags away the remains of a cub that he caught and killed in the Churchill Wildlife Managment Area on Nov. 20. (Daniel J. Cox/NaturalExposures.com)Infanticide occurs among all species of bears but can become accentuated among polar bears when they run low on fat reserves and become hungry enough to resort to cannibalism, according to Polar Bears International, a non-profit organization dedicated to the worldwide conservation of polar bears and their Arctic habitat.

Scientists predict that with later formation of ice in the fall and earlier breakup in the spring because of climate warming, polar bears in places like western Hudson Bay will have to survive on land for longer on their diminishing fat reserves instead of hunting seals.

"At this time of year, polar bears are hungry because they have been surviving on their stored fat reserves since the ice cover of Hudson Bay broke up a few months ago. Thus, days they spend waiting for the sea ice to return, they are losing weight and eventually get quite hungry," said Stirling, who has studied the western Hudson Bay polar bear population for over 35 years.

'Days they spend waiting for the sea ice to return, they are losing weight and eventually get quite hungry.'—John Gunter, Frontiers North Adventures

"During the summer and autumn, polar bears lose up to 30 per cent of their body mass because they burn up to one kilogram of stored body fat every day while they are waiting for the ice to freeze.

"We have observed that the average body condition of the western Hudson Bay polar bears has been declining for almost 30 years. By mid-to-late November, if they can't get on the sea ice to feed on seals, males may seek out alternate food sources."

Killing of a cub for food by an adult male has also been recorded in Svalbard, in the Norwegian Arctic, said Stirling.

And in the southern Beaufort Sea, where the body condition of polar bears has also declined apparently because of deteriorating ice conditions, there have been four cases of cannibalism by adult male bears in the last few years.

In those four cases, the victims were three adult females and one yearling, according to Stirling.

Ice breaking up earlier than ever

The average date of breakup of the sea ice in western Hudson Bay is about three weeks earlier than it was 30 years ago, although there is a lot of variation between years, said Robert Buchanan, president of Polar Bears International.

'While these images are very difficult to look at, we need to remind people that there is hope and each of us can help save polar bears and their habitat.'—Robert Buchanan, Polar Bears International

In 2008, the breakup was later, in early August, so the bears came ashore in better condition than in most recent years.

But that advantage has been lost due to the current delay in freeze-up, Buchanan said.

This year may be an even longer wait for the bears to return to the sea ice to hunt as the current long range forecast calls for above average temperatures in the region until the second week of December.

Twenty years ago, the average date the bears returned to the ice was Nov. 8, Buchanan noted.

"While these images are very difficult to look at, we need to remind people that there is hope and each of us can help save polar bears and their habitat," he said about the photos provided by the organization of the Nov. 20 incident of cannibalism.

With files from The Canadian Press