Allen's Big-eared Bat - Illustration by George Maleski
Allen's Big-eared Bat
Idionycteris phyllotis


The Allen's big-eared bat is a tawny colored bat about two inches in length with a wingspan ranging from 12 to 14 inches. The bat has large ears, one and one half inches, with two fleshy lobes, called lappets, projecting forward from the base of the ears. The bat can protect its ears by folding and coiling the ears into "ram's horns" which lay along the sides of the bat's neck.

Habitat: In Arizona, this bat is known to roost in abandoned mine shafts, most often in ponderosa pine, pinyon juniper Mexican woodland, and riparian areas of sycamores, cottonwoods and willows. This species is often found near boulder piles, cliffs, rocky outcroppings, or lava flows.

Range: The bat is found in elevations from 2,600 to 9,800 feet, though most individuals are found between 3,500 and 7,500 feet. Allen's big-eared bats are known to range from the Colorado River Valley of Arizona to New Mexico and the central highlands of Mexico. Within Arizona, this species is best known to occur along the Mogollon Rim and adjacent mountain ranges. Records of occurrence exist in the following counties: Mohave, Coconino, Yavapai, Gila, Graham, and Cochise.

Diet: This species of bat is primarily insectivorous, feeding primarily on soft-bodied insects such as small moths, soldier beetles, dung beetles, leaf beetles, roaches, and flying ants.

Reproduction: Little is known about the reproductive history of this species. In Arizona, females form maternity colonies in early summer. Young are born in mid- to late July, and begin to fledge by the end of July. Maternity roosts are known in the Kingman area and in the vicinity of Aravaipa Canyon.

Status: The Allen's big-eared bat is a Federal Species of Concern. The Western Bat Working Group rates this species as imperiled or at high risk of imperilment.

Allen's Big-eared Bat in Pima County: There are no records for this species in Pima County. It has been included in the Sonoran Desert Conservation Plan because of the possibility that it may be found here. A likely place to look for this species would be the San Pedro River and mine tunnels along the river side of the Catalina Mountains in northeastern Pima County.



1. Recon. 2001. Draft Priority Vulnerable Species. Analysis and Review of Species Proposed for Coverage by the Multiple-Species Conservation Plan. Pima County Administrator's Office.


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