A hibernaculum plural form: hibernacula (Latin, "tent for winter quarters") is a place in which a creature seeks refuge, such as a bear using a cave to overwinter. The word can be used to describe a variety of shelters used by many kinds of animals, for instance, insects, toads, lizards, snakes, bats, rodents, and primates of various classes.
Hibernaculum (zoology) Wikipedia
Like other animals, mammals hibernate during seasons of harsh environmental conditions and resource scarcity. As it requires less energy to maintain homeostasis and survive when an individual is hibernating, this is a cost-effective strategy to increase survival rates. Hibernation is usually perceived as taking place during winter, as in the most well-known hibernators bears and bats, but can also occur during the dry season when there is little food or water, as in the mouse lemurs of Madagascar. Given that mammals can spend anywhere from 1–9 months hibernating, their choice in hibernaculum in essential in determining their survival.