What term describes a cave or other site where bats hibernate?

A hibernaculum is a cave or other sheltered site where an animal spends the winter in hibernation. For bats, a cave, abandoned mine, cellar, or similar underground space can serve as a hibernaculum, providing the cool, stable, and humid conditions needed to conserve energy.

The word comes from Latin and originally referred to winter quarters or a winter shelter. It is broader than “roost,” which means a place where bats rest at any time of year. “Den” is also too general: it may describe a mammal’s shelter, but it does not specifically identify a site used for hibernation.

Many bats return to the same hibernacula year after year, sometimes gathering in large colonies. During winter, their metabolism, heart rate, and body temperature fall sharply. Disturbance can be dangerous because waking forces a bat to burn precious stored fat when insects are unavailable.

Hibernacula are important conservation sites. White-nose syndrome, a fungal disease, has devastated bat populations in some North American caves. As a result, entrances to important hibernacula may be gated or seasonally closed to protect sleeping bats from human disturbance.