🔗 Share this article

Researchers monitoring free-roaming polar bears in northern Canada witnessed something remarkably uncommon this fall: a mother bear taking in a cub that was not genetically her own.

The five-year-old maternal bear and her nearly year-old cubs were observed and filmed during the annual polar bear migration along the Hudson Bay's western shore near the Manitoba town of Churchill, an area renowned for its concentration of Arctic bears.

"This is uncommon," remarked a researcher with a polar bear conservation group. "We don't really know why it occurs...but we know it doesn't happen often at all."

This represents only the thirteenth documented instance of fostering out of 4,600 bears researched for almost fifty years in the area.

The mother bear was first captured as she emerged from her maternity den this spring. Initially, she had a single offspring, which scientists marked for research.

In the autumn, she was seen again, but this time with a pair of cubs - the original cub and a second that was untagged. Scientists are uncertain what became of the new cub's biological mother, but they are trying to locate her using DNA analysis.

"These animals need every advantage they can get these days with a warming climate," noted a wildlife biologist. "If females have the chance to take in an additional youngster and care for it and successfully wean it, it's a positive development for the population."

Polar bears in the wild only have a fifty-fifty survival rate of surviving into maturity, but having a maternal figure providing care improves their odds.

The cubs appear to be healthy, researchers said, and they will probably stay with their mother until they are about 30 months of age.

Next, the family is expected to venture out to the frozen ocean, where the youngsters will be taught from their mother bear how to catch prey and live on their own.

"It is heartening to know that the animals are caring for each other," concluded the scientist.