The Hoary bat is an insectivorous species of bat that lives in the Americas. Its coat is dense and dark brown, with white tips to the hairs that give the species its 'hoary' appearance for which it is named. The body is covered in fur except for the undersides of the wings.
Hoary bats are found throughout most of North America and much of South America, with disjunct populations in the Galápagos Islands and Hawaii. They live in woodlands, mainly coniferous forests, but hunt over open areas or lakes.
Hoary bats are generally solitary and typically roost alone on trees, hidden in the foliage; however, they may sometimes roost in caves with other bats and form groups during migration and the breeding season. They hunt alone and can cover an impressive 39 km (24 mi) in one night while foraging. Hoary bats are long-distance migrants. They spend the winter in Central America and the southwestern United States and the spring and summer in more northern latitudes in the United States and Canada. However, some northern populations are believed to remain in their native region and hibernate for the winter.
The reproductive cycle of Hoary bats is not yet fully documented. It is thought that they mate in August and births usually occur in June of the following year. It is thought that the gestation period is only 40 days and the female bears a single pup, or sometimes twins. The young are born blind and partially furred, and spend about a month with the mother before dispersing.
Hoary bats are not listed as threatened or endangered, however, they suffer significant mortality from wind turbines. Most bat deaths occur during migration in the spring and fall. It is suggested that bats are attracted to the tall structure, possibly believing them to be trees that can be used for rest. In some areas of their range, Hoary bats also suffer from deforestation and human disturbance.
According to IUCN, the Hoary bat is common throughout its range but no overall population estimate is available. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.
Hoary bats are important predators of insects in their ecosystem and thus keep populations of their prey species in check.