A little brown bat by Ann Froschauer, USFWS.

A colony of bats exit Bracken Cave in Texas. Photo by by Ann Froschauer, USFWS.

The Townsend's big-eared bat by Ann Froschauer, USFWS.

California leaf-nosed bats by Kristen Lalumiere, National Park Service.

A colony of bats by Alan Cressler, USGS.