“Cub adoption is relatively rare in polar bears. We’ve documented 13 cases in our study population over the last 45 years,” said Evan Richardson, a scientist with Canada’s ministry for environment and climate change.

The footage of a bear caring for an adopted cub was captured during the annual polar bear migration along the Western Hudson Bay in Churchill, Manitoba, widely known as the polar capital of the world.

Canadian researchers encountered the mother in the spring as she left her maternity den. She had only one cub, which was tagged — a common practice to aide study of the population.

They encountered the same mother again weeks ago but saw a second cub with no ear tag, Richardson told AFP.

“When we went back and looked at the data, we realized that she had adopted a second cub,” he said.

Video footage collected by the researchers shows the cubs surveying a snow-covered landscape, with the mother pacing behind, and one sequence where one cub hurries to join the others.

Both cubs are 10 to 11 months old, and will likely stay with their mother until about 2.5 years of age.

Researchers currently have no information as to what happened to the adopted cub’s biological mother.

But having a maternal figure increases the chances of the cub’s survival into adulthood, Richardson said.

“It’s really a feel-good story to know that this female bear is looking after this cub and that it has a chance at survival,” he said.

“These female polar bears are such good moms, they’re maternally primed to take care of offspring, and when there’s a lone cub out on the tundra, bawling and crying, they just take them under their wing,” he added.

bs/sla