Bears also hibernate, but this hibernation behavior is not as pronounced in bears as it is in snakes and tortoises. Bears' hibernation is often referred to as the "hibernation period" or "dormant period," a period in which bears reduce their activity and enter an energy-saving mode in response to food scarcity and cold climates.
Different species of bears have different hibernation habits. For example, North American black bears and grizzly bears enter burrows or dug hibernation burrows during the winter months, where they enter a semi-dormant state. During this time, their metabolism slows down and their body temperature, heartbeat, and respiratory rate decrease, but they still wake up occasionally and sometimes leave their burrows in search of food during the warmer months.
However, brown bears (including polar bears) usually do not fully hibernate during the winter months and will continue to forage for food, albeit with reduced activity. Polar bears are particularly adapted to extreme cold conditions, and they will continue to move on the ice during the winter months in search of food such as seals.
During hibernation, bears consume the fat they store in the fall, which helps them stay alive during the winter months when food is scarce. When spring arrives, the temperature rises and food becomes abundant, bears leave their hibernation grounds and begin to search for food and resume their activities.