Family: Vespertilionidae, Vespertilionid Bats view all from this family

Description Tawny above, with hairs dark brown at base; underparts slightly paler. No fur on wings or membranes. Tragus 5/8" (16 mm) long. White patches behind enormous ears; flap projects forward from base of ear. L 4-4 5/8" (103-118 mm); T 1 3/4-2 1/8" (46-55 mm); HF 3/8" (10-11 mm); FA 1 5/8-1 7/8" (42-48 mm); E 1 5/8" (40 mm); Wt 3/8 oz (10.4-13.2 g).

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.

Similar Species No other big-eared bat has similar ear flaps.

Breeding 1 young born in maternity colony in early summer.

Habitat Forested mountains. Roosts in caves and mines.

Range Southeastern California west through Arizona and w New Mexico.

Discussion Like other big-eared bats, this species emerges long after dark to feed. Its ears lie back when it is resting, becoming erect if it is disturbed. Females separate from males and form maternity colonies in protected places in rocks or mines. Three colonies observed had 25, 30, and 97 individuals.