Deer in Spring Landscape

Photo of Big Brown BatBig Brown Bat
(Eptesicus fuscus)


Description:

  • Recognition:
    • Glossy brown-copper fur;
    • Belly paler; Wings/interfemoral membrane black;
    • Tragus short, broad and rounded;
    • Face/ears broad and black; Keeled calcar.
  • 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)

Roosts:

  • Summer Roost: Buildings, under bridges, hollow trees, beneath loose bark, behind shutters.
  • Winter Roost: Buildings, caves, mines.

Diet:

Beetles, ants, flies, mosquitoes, mayflies, stoneflies, other insects.

Similar Species:

  • Evening Bat much smaller.
  • Myotines (genus Myotis) usually smaller, with 2 tiny premolars behind canine and longer, thinner tragus.

Sounds:

Big Brown Bat Call
Courtesy of Bat Call: Acoustic Call Library and Species Accounts

Big Brown Bat Spectrograph
Courtesy of Bat Call: Acoustic Call Library and Species Accounts

Return to Field Guide to Maryland Bats

Photo by: Dr. J. Scott Altenbach