Kentucky Bat Working Group

Big Brown Bat (Eptesicus fuscus)

Description: One of Kentucky’s largest bats, the big brown sometimes attains a length of nearly 5 inches (127 mm) and can have a wingspan of more than 13 inches (330 mm).  These bats are glossy brown in color, slightly lighter below.  They have a large head with a broad nose, a rounded tragus and a keeled calcar.

Range: Occurs throughout most of North America from central Canada, south through Central America into northern South America.

Kentucky Occurrence Summary: The species is a year-round resident in Kentucky, in all likelihood not moving great distances between winter and summer roost sites. Big brown bats occur nearly statewide, although they appear to be absent from the Mississippi Alluvial Plain in the far western part of the state.

Distribution in Kentucky:  

Habitat and Life History: Big brown bats are associated primarily with human structures during the spring, summer, and fall.  Consequently, they are the bats most often encountered by humans.  All known Kentucky maternity sites have been found in buildings of some type or under bridges.  These hardy bats also roost in the eaves of buildings during winter unless the temperatures become too extreme.  In winter, big brown bats hibernate primarily in caves where they are usually found in the coldest sections near the entrance.  Big brown bats have adapted well to the changes that humans have brought to the landscape, and they are often found in association with settlement.  The species forages in a great variety of open and semi-open habitats, often around both urban and rural street lights.  These bats have relatively large teeth, which aid them in consuming their preferred prey -- beetles.  Maternity colonies typically consist of from several to more than a hundred females.  Each bat generally gives birth to twins in early June.  Males may join the maternity colonies or roost alone.  In winter, these bats typically roost singly or in small groups of less than a half-dozen individuals in caves, often in crevices in the rock.


Useful links:

Animal Facts: Big Brown Bat

Animal Diversity Web - Big Brown Bat

Bat Echolocation Station - Big Brown Bat

Big Brown Bat, Eptesicus fuscus

Mammals of Texas - Big Brown Bat

Ohio Division of Wildlife - Big Brown Bat

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