🔗 Share this article

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

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

"It's unusual," remarked 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."

It's only the 13th known case of fostering out of nearly five thousand bears studied for almost fifty years in the area.

The female bear was initially tagged as she emerged from her maternity den this spring. At the time, she had a single offspring, which scientists marked for research.

In the fall, she was spotted once more, but this time with a pair of cubs - the initially tagged cub and another that was untagged. Researchers aren't sure what happened to the new cub's birth mother, but they are trying to identify her using genetic samples.

"The bears need every advantage they can get in the current era with climate change," noted a polar bear scientist. "When mother bears have the opportunity to pick up another cub and raise it and successfully wean it, it's a good thing for the population."

Polar bears in the wild only have a 50% chance of surviving into maturity, but having a mother caring for them boosts their odds.

The young bears are reported as healthy, researchers said, and they will likely remain with their mother until they are about two-and-a-half years old.

Following this, the bear family is expected to head out to the frozen ocean, where the youngsters will learn from their mother how to hunt seals and live on their own.

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