hibernator

A hibernator is an animal that enters a state of dormancy known as hibernation. This state is characterized by significantly lowered body temperature, slowed breathing and heart rate, and a reduced metabolic rate. Hibernation is typically a response to cold environmental conditions and a scarcity of food resources during winter months. Animals that hibernate often gain a large amount of weight before entering this state, storing fat reserves that will provide energy during dormancy.

During hibernation, the animal's physiological processes slow down to conserve energy. Body temperature can drop to just a few degrees above freezing, and heart rate might decrease from dozens of beats per minute to a mere handful. Breathing becomes shallow and infrequent. While in hibernation, animals are largely unresponsive to external stimuli. They may periodically wake up for short periods, during which their body temperature returns to normal, and then re-enter hibernation.

Common examples of hibernating animals include bears, groundhogs, bats, and certain species of mice and squirrels. However, not all animals that reduce activity in winter are true hibernators. Some may enter a less profound state of dormancy called torpor, which is shorter in duration and involves less extreme physiological changes. The ability to hibernate is an evolutionary adaptation that allows certain species to survive harsh winter conditions when food is scarce and temperatures are low.