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Big Brown Bat Eptesicus fuscus


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Big Brown Bat
credit: Calliopejen1

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Family: Vespertilionidae, Vespertilionid Bats view all from this family

Description As the name suggests, this is a large brown bat with naked, dark membranes. The tail is enclosed in interfemoral membrane. It has short ears, a keeled calcar, and a forearm length of 39-54mm. They use hollow trees, but are equally common in buildings, including barns and churches. Although hibernacula in caves are common, this species also sometimes hibernates in cold buildings.

Dimensions 87-138mm, 34-56mm, 11-23g

Warning Bats are susceptible to rabies, a serious viral disease that results in death if untreated. Rabid bats rarely attack humans or other animals, but bats found lying on the ground may be rabid. Never touch or pick up any bat. Stay away from any animal that seems to be acting strangely and report it to animal-control officers. If you are bitten by a possibly rabid animal, you must immediately consult a doctor for a series of injections; there is no cure once symptoms emerge.

Breeding Males are solitary in spring and summer, but females gather in small maternity colonies of 20-75 individuals and their young.

Habitat Forests & woodlands, Cities, suburbs & towns, Canyons & caves

Range Plains, Great Lakes, New England, Mid-Atlantic, Rocky Mountains, Southeast, Southwest, Florida, Texas, California, Northwest, Eastern Canada, Western Canada

Discussion Widely distributed throughout North America, this species occurs in a wide variety of habitats, and frequently roosts in man-made structures.