Big brown bat

The Big Brown Bat (Eptesicus fuscus) is larger in size than comparative species of bats, from about 4 to 5 inches (10 – 13 cm) in body length, with a 11-13 inch (28 to 33 cm) wingspan and weighing 1/2 to 5/8 ounce. 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. Big brown bats are known also to produce audible sound during flight. Its voice is a click or a sound like escaping steam.

Diet

Big brown bats are insectivorous, eating many kinds of night-flying insects including mosquitoes, 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 than their summer roosts. Winter roosts tend to be natural subterranean locations such as caves and underground mines where temperatures remain stable; it is still unknown where a large majority of Big Brown Bats spend the winter. If the weather warms enough, they may awaken to seek water, and even breed.

Life cycle

Big brown bats mate sporadically from November through March. After the breeding season, pregnant females separate themselves into maternity colonies.

Subspecies

• Eptesicus fuscus fuscus (Palisot de Beauvois)
• Eptesicus fuscus pallidus (Young)

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

References

• Reader's Digest North American Wildlife Mammals, Reptiles and Amphibians (2nd Edition ed.). Reader's Digest. ISBN 0-7621-0035-4. 

External links

• Eptesicus fuscus Echolocation Lab at Brown University
• NewScientist.com Article from issue 2581 of New Scientist magazine, 06 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