Polar bears sleep on the open ground, dig pits in gravel and sand at shorelines, or dig shallow areas in the snow or beneath protected ridges. Once inside these protective depressions, they turn their backs to the wind.
During blizzards, the snow covers and insulates the bears from the cold. Polar bears sleep seven to eight hours a day, and they take numerous naps. In the Arctic, where darkness lasts 24 hours in the winter and light lasts 24 hours in the summer, whether the bears sleep during the day or night is of little significance. However, a polar bear's main prey, the seal, is most active at night. Hunting takes energy, so polar bears nap often to help conserve energy.