Idionycteris phyllotis (Allen's Big-eared Bat)

Weight: 8-16 grams

Wingspan: 31-35 centimeters


Southwestern United States to central Mexico.


[Call File1] [Call File2] [Call File3] [Call File4] [Call File5] [Call File6]
[Call File7] [Call File8] [Call File9] [Call File10] [Call File11] [Call File12]

[Spectrograph1] [Spectrograph2]

Ecology and Behavior:

A rather large bat with enormous ears and a unique pair of lappets projecting from the median bases of the ears over the top of the snout. When at rest, the huge ears lie along the back, often curled into the shape of a ram's horn. Allen's big-eared bat usually inhabits forested areas of the mountainous Southwest, and is relatively common in pine-oak forested canyons and coniferous forests, but it also may occur in non-forested, arid habitats. At most sites where this species occurs, cliffs, outcroppings, boulder piles, or lava flows are nearby. Day roosts may include rock shelters, caves, and mines. It leaves the roost only after complete darkness, and usually flies about 10 meters (33 feet) above ground. It emits loud calls at about 1-second intervals. Flight is slower than the free-tailed bats, but swifter than most other bats. In close quarters, this species flies slowly, is highly maneuverable, able to hover, and can fly vertically. In more open situations, it uses fast, direct flight. The sexes segregate geographically during summer months, with females gathering into maternity colonies and males possibly remaining solitary, roosting elsewhere. Seasonal movements and winter whereabouts and activities are unknown.

Food Habits:

Primarily small moths, but soldier beetles, dung beetles, leaf beetles, roaches, and flying ants also are eaten.

Reproduction and Longevity:

One baby is born in June or July.

Status of Populations:

Locally common, but rare over most of range.

Text, in its original form, provided by T. L. Best, M. J. Harvey, and J. S. Altenbach. Printed spectrographs provided by M. J. O'Farrell. Distribution maps, call descriptions, and AnaMusic sound clips produced by W. L. Gannon. Accounts assembled by T. C. Sanchez-Brown.