At birth, polar bears are blind, nearly hairless and weigh just over a pound—about the same as a loaf of bread. But they spend their first few months snuggled inside a snowy den, fattening up on their mother’s milk.

Researchers use remote camera footage and satellite collars to gain new insights into polar bear denning behavior and cub survival. The denning period is the most critical time in a polar bear’s life.

Every wondered why polar bears don't freeze in the extreme temperatures of the Arctic? Well, scientists finally have the answer.