A group of bats is a colony and the offspring are pups. Despite a reputation for carrying rabies, bats are extremely beneficial because they control night-flying insect populations, including moths, beetles, termites, flies and mosquitoes, according to the Washington Department of Fish & Wildlife.
Bats roost in several locations, including hollow trees, buildings, caves or underground, and they establish separate roosts for hibernation and maternity. Roosts protect bats from predators, and hanging upside down from structural roosts facilitates a swift and smooth flight take-off. Some bats hibernate for five or six months, while others migrate to moderate weather regions where food is plentiful. In Washington state, less than one in 20,000 bats contracts rabies.