The hoary bat (Lasiurus cinereus) is a species bat in the vesper bat family, Vespertilionidae. It occurs throughout South America, with disjunct populations in the Galapagos and Hawaiian Islands. The bat normally roosts alone on trees, hidden among foliage, but on occasion has been seen in caves with other bats. It prefers woodland, mainly coniferous forests, but hunts over open areas or lakes. It hunts alone and its main food source is moths. With the major exception of the underside of the wing, most of the bat is covered in fur.
Ten Facts about Hoary Bat
- Average measurements of adults are; total length, 136 mm (5.4 in); tail, 60 mm (2.3 in); ears, 17.5 mm (.7 in); wingspan, 403 mm (16 in); weight, 26 g (.9 oz). Maximum wingspan is 415 mm (16.5 in) and weight is 36 g (1.25 oz).
- Its pelage is long, dense and silky. The individual hairs have four bands of colours; beginning from the base, slate-coloured, then tawny-yellow, followed by dark brown and ending with silver tips. This results in an over-all effect of a dark mahogany brown with a silvery frosted back, suggesting its name, Hoary.
- Normally a solitary tree-dweller, roosting in the leaves, it has on occasion been seen hunting in groups and roosting in caves. It usually emerges very late, so is seldom observed. Its flight is strong, direct and swift, 14.5-21 kph (9-13 mph).
- The Hoary Bat migrates south for the winter, beginning in late August. Our population likely ends up in the southern USA. During migration, they may be seen flying in daylight hours. They return in late May.
- During summer, there is a total segregation of the sexes. Males seem to wander erratically.
- The two to four young are born in late June. The young are carried by the female during her hunting forays until they are about half-grown.
- One female was "grounded', carrying two young whose combined weight was 25 5 greater than her own. By 28 days of age, most young have learned to fly and become independent.
- It prefers to feed on insects flying over streams, bays, or along the seacoast, and it can eat up to 40% of its own body weight in a single feeding.
- The Hawaiian hoary bat is listed as endangered under the Federal Endangered Species Act. They are the only bat and the only land animal native to Hawaii.
- Loss of the trees in which the bats roost may be the main reason for their declining numbers, according to the U.S. Fish and Wildlife Service. Hoary bat populations outside Hawaii are not considered threatened.
