Calgary Herald

Early ice melt threatens polar bears

- RYAN CORMIER

The population of the North’s iconic polar bear could be dealt yet another blow due to climate change, the results of a new Canadian study suggest.

The study from the University of Alberta predicts that if the thaw in Hudson Bay occurred a month earlier, anywhere from 40 to 73 per cent of pregnant bears in the region would fail to give birth to cubs. And, if the ice breakup occurs two months earlier, 55 to 100 per cent of potential mothers would not give birth. At the same time, the average litter size could drop, with triplets becoming more rare and single births the new norm, the study says.

Whilethose­numberswil­l vary from year to year, says the man behind the study, they also will determine how quickly the polar bear population could drop.

“This is another piece of the puzzle of looking at how climate change could affect polar bears,” says biological science professor Andrew Derocher. “What should we be watching for in these population­s? There’s no indication this population is sustaining itself.”

For roughly eight months of the year, free to roam the Hudson Bay ice, female polar bears gorge on prey. The less time that ice holds, the less time bears have to accumulate the more than 200 kilograms of fat needed to carry a cub to term.

Polar bears mate in the spring, but the fertilized egg isn’t implanted in the womb until the fall. If a mother cannot carry the cub, or lacks the weight to lose nearly two kilos a day to feed one, her body will abort the pregnancy.

 ?? Courtesy, Andrew Derocher ?? U of A’s Andrew Derocher says fewer polar bear cubs would be born if ice on Hudson Bay thawed earlier.
Courtesy, Andrew Derocher U of A’s Andrew Derocher says fewer polar bear cubs would be born if ice on Hudson Bay thawed earlier.

Newspapers in English

Newspapers from Canada