Big Brown Bat
(Eptesicus fuscus)
Colonial
Weight
1/2 - 5/8 oz. (13-18 g)
Body Length 4 - 5 1/8 in. (103-130 mm)
Wingspan
13-16 in. (32-40 cm)
Forearm 1 3/4 - 1 7/8 in. (45-48 mm)
Recognition Glossy brown-copper fur.

Belly paler.

Wings/interfemoral membrane black.

Tragus short, broad and rounded.

Face/ears broad and black.

Keeled calcar.
Similar Species Evening Bat much smaller.

Myotines (genus Myotis) usually smaller, with 2 tiny premolars behind canine and longer, thinner tragus.
Summer Roosts Buildings, under bridges, hollow trees, beneath loose bark, behind shutters.
Winter Roosts Buildings, caves, mines.
Eats Beetles, ants, flies, mosquitoes, mayflies, stoneflies, other insects.
Call

.wav file

Courtesy of Bat Call: Acoustic Call Library and Species Accounts

Spectrograph

Courtesy of Bat Call: Acoustic Call Library and Species Accounts


Photo of Big Brown Bat

Big Brown Bat

Photo by:
Dr. J. Scott Altenbach

Return to Field Guide to Maryland Bats