Rare polar bear cub adoption captured on video

The polar bears of Western Hudson Bay are the best studied in the world, but researchers there still encounter surprises from time to time. During the annual polar bear migration near Western Hudson Bay in Churchill, Manitoba, a wild female polar bear was filmed exhibiting a rare and surprising behaviour: the adoption of a cub that is not her own.

How do we know the cub is adopted?

Researchers from Environment and Climate Change Canada first encountered the mother, known as bear X33991, in the spring of 2025 as she emerged from her maternity den with a single cub. When the team observed her again in the fall, she was accompanied by two cubs — the one they had tagged, and an unknown cub. This new addition strongly suggested an adoption.

To confirm this, the researchers took genetic samples from the new cub and are currently analyzing them in hopes of identifying its biological mother.

The cubs are likely around 10 to 11 months old and look healthy. “Polar bear cubs will stay with their moms for between two and two and a half years”, according to Alysa McCall, Polar Bears International’s director of conservation outreach and staff scientist. “It's not a lot of time to learn how to be a polar bear. But they do soak up a lot of lessons in that short period of time.”

How rare is polar bear adoption?

Polar bear adoptions are considered very rare. The Western Hudson Bay subpopulation has been studied for over 45 years, with researchers tracking more than 4,600 individual bears. This recent observation marks only the 13th known case of adoption in this vast dataset.

The identity and fate of the adopted cub's biological mother is currently unknown. However, evidence from previous adoption cases has shown that the biological mothers were sometimes still alive. That suggests that adoption can sometimes be a "switching of litters" rather than a cub being completely orphaned.

How did we identify the mother?

The mother bear is part of an ongoing research program led by Environment and Climate Change Canada and the University of Alberta, and is wearing a GPS tracking collar. These collars are vital tools that help scientists monitor polar bear movements, habitat use, survival rates, denning areas, and time spent on the sea ice for feeding. Thanks to this data, researchers and policymakers get critical information to better protect the species in a changing climate.

Follow the movements of polar bears, including X33991, on our Polar Bear Tracker.

What’s next for these polar bears?

X33991 and her two cubs have now moved out onto the sea ice, where the mother will hunt seals and teach both cubs essential survival skills. While only about half of polar bear cubs make it to adulthood, having a mother significantly improves the adopted cub’s chances. 

In Western Hudson Bay, researchers have seen 3 out of the 13 known adopted cubs survive to adulthood. Currently, they don't think cub adoption is linked to climate change but instead is likely tied to strong maternal instincts.

“The fact that this cub got adopted and has a chance to learn lessons about being a bear and to be taken care of for a couple years really does give it a shot at making it to adulthood”, says Alysa.

“It's just another reason why the species is so incredible, why they're so fascinating and interesting. It gives you a lot of hope when you realize that polar bears maybe are looking out for each other out there.”