Allen's big-eared bat

Idionycteris is a bat with large ears, weighing 8 to 16 grams. On the dorsal side they possess long and soft pelage,[3] also referred to as fur. Their fur is basally blackish in color with tips that are a yellow-gray color. Idionycteris, has a black patch on each shoulder, a tuft of white hair on the backside of the ears, as well as, ventral hairs that are black with pale tips.[3] The calcar possesses a low keel. The uropatagium has 12 to 13 transverse ribs. The rostrum is flattened and broad.[3]

Idionycteris phyllotis has an external morphology like that of gleaning bats, which means they have adaptions required for plucking stationary insects from surfaces.[3] To do this, they have long tragi and ears, wings adapted for maneuverability and hovering flight, and a gracile jaw.[3] Allen’s big-eared bat (Idionycteris phyllotis) is the only species in North America known to emit long, constant frequency-frequency modulated echolocation calls.[2]

The Allen’s big-eared bat inhabits the southwestern mountainous regions of Mexico and the United States. This species, occupies a wider range in elevation, ranging from 855 m to 3,225 m, while most specimens reside at altitudes between 1,100 m and 2,500 m.[3]