Big brown bat

Big brown bat Eptesicus fuscus
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Chiroptera
Family:	Vespertilionidae
Genus:	Eptesicus
Species:	E. fuscus
Binomial name
Eptesicus fuscus (Palisot de Beauvois, 1796)
Regional distribution of the big brown bat (gray areas)

The big brown bat (Eptesicus fuscus) is native to North America, Central America, the Caribbean, and extreme northern South America.

Description

Vocalizations of the Big brown bat vary with behavioral context

This medium-sized bat ranges from 4 to 5 in (10–13 cm) in body length, with an 11- to 13-in (28- to 33-cm) wingspan, and weighs between 1/2 and 5/8 oz (14-16 g). The fur is moderately long and shiny brown. The wing membranes, ears, feet, and face are dark brown to blackish in color.

Big brown bats are nocturnal, roosting during the day in hollow trees, beneath loose tree bark, in the crevices of rocks, or in man-made structures such as attics, barns, old buildings, eaves, and window shutters. Big brown bats navigate through the night skies by use of echolocation, producing ultrasonic sounds through the mouth or nose. They are known also to produce audible sound during flight, a click or a sound like escaping steam.

Diet

Big brown bats are insectivorous, eating many kinds of night-flying insects including moths, beetles, and wasps which they capture in flight. This causes the sudden, frequent changes in direction.

Hibernation

Big brown bats hibernate during the winter months, often in different locations from their summer roosts. Winter roosts tend to be natural subterranean locations such as caves and underground mines where temperatures remain stable; where a large majority of these bats spend the winter is still unknown. If the weather warms enough, they may awaken to seek water, and even breed.

Big brown bats (Eptesicus fuscus) roost in a Minnesota barn.

Lifecycle

Big brown bats mate sporadically from November through March. After the breeding season, pregnant females separate themselves into maternity colonies. In the eastern United States, twins are commonly born sometime in June; in western North America, females give birth to only one pup each year.

Subspecies

The subspecies E. f. fuscus occurs in the entire eastern half of the U.S. except Florida. The subspecies E. f. pallidus occurs in Utah.

See also

• Bats of Canada
• Bats of the United States

External links

External audio
Bat Chirp
click here to listen to the Big Brown bat chirp

• Eptesicus fuscus Echolocation Lab at Brown University
• NewScientist.com Article from issue 2581 of New Scientist magazine, 6 December 2006, page 21- Claims bats can navigate by sensing Earth's magnetic field
• Identifying Big Brown Bats by Professional Humane Bat Removers in New England
• Video of Big Brown Bat from Boulder, CO