Hibernation is a dormant state experienced by some animals that includes a slow metabolic rate, inactivity, lower body temperatures, and slowed respiratory rate. It is a method of energy conservation that typically occurs in winter when food is more scarce. Hibernation can last for days or even weeks. Some animals gestate their young during hibernation.
Examples of animals who hibernate include some species of bats, squirrels, some rodent species, hedgehogs, marsupials, and snakes. Some species of bears also hibernate but it isn't as deep as the animal species previously mentioned. Bears who hibernate have a higher body temperature and metabolic rate which means they can be wakened more easily.