Only females, especially pregnant females, enter into a state of carnivore lethargy, or "hibernation". They do so from about October or November through March or April. The female polar bear's heart rate slows to about 27 beats per minute from a normal resting heart rate of about 46 beats per minute.

Do polar bears hibernate during winter months?

A: Female and male black and brown bears hibernate over the winter months. ... Polar bears do not hibernate. Only pregnant polar bears den. Unlike hibernation, a polar bear's heart rate and temperate do not decrease, this ensures the cubs will stay warm.

Do polar bears hibernate in the summer?

Polar Bears Don't Go Into Hibernation-Like State in Summer, Researchers Say. Scientists have long considered the possibility that polar bears enter a kind of walking hibernation to cut down their energy demands during the summer, when food on land is scarce.