🔗 Share this article

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

The half-decade-old maternal bear and her 10- to 11-month-old cubs were observed and filmed during the yearly polar bear migration along the Hudson Bay's western shore near Churchill, Manitoba, an area renowned for its concentration of Arctic bears.

"It's unusual," stated a researcher with a polar bear conservation group. "The reasons are unclear why it happens...but we know it doesn't happen often at all."

This represents only the 13th known case of fostering out of 4,600 bears studied for nearly five decades in the area.

The female bear was initially tagged as she came out from her maternity den this spring. At the time, she had a single offspring, which researchers tagged for study.

In the fall, she was spotted once more, but this time with two cubs - the initially tagged cub and another without a tag. Scientists are uncertain what became of the second cub's biological mother, but they are trying to identify her using genetic samples.

"The bears need every advantage they can get these days with climate change," noted a wildlife biologist. "If females have the chance to take in another cub and care for it and see it to independence, it's a good thing for the population."

Polar bears in the wild only have a 50% chance of living into maturity, but having a maternal figure providing care improves their odds.

The young bears appear to be in good condition, according to experts, and they will likely stay with their mother until they are about 30 months of age.

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

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