In the fall, when the days shorten and temperatures become colder, black bears look for a den to hibernate. They choose an old tree stump or a place where roots form a cave-like structure. This den will be large enough for the male or for the female with its cubs. The female covers the ground with grass or leaves. The female starts to winter sooner than the male, which often waits for the first snowfalls in November to enter the den.

The bear’s body temperature goes down slowly, while its heartbeat slows down. It gets the calories it needs for its basic metabolism to work from its fat reserves. During the winter, it doesn't eat, urinate nor defecate. If the temperatures go up during the winter, the bear can wake up and walk around its den a little.

When spring arrives, the bear gets out of its den and looks out for food. Its clothes (its skin) have become too big for the bear, since during its wintering, it lost 30% to 35% of its weight.

To winter means to spend the winter in a shelter, while to hibernate means to spend the winter in a state of deep sleep.