The Townsend’s big-eared bat is easily identifiable by its extremely large ears which measure nearly half its body length. Other distinguishing features include a long, pointed tragus and a short snout with pronounced lumps on either side. Its pelage is variable, with dorsal fur ranging from gray to reddish- or blackish-brown; and gray ventral fur showing brown or buff tips. It is a wide-ranging species, found from southern Canada to southern Mexico, occupying diverse habitats including coniferous forests, oak-hickory forests, and grasslands. Townsend’s big-eared bats typically roost in cliffs, caves, and rock ledges, hibernating in areas with substantial airflow. The species feeds mostly on moths but occasionally preys on other small insects. Females produce a single pup per reproductive cycle. The oldest recaptured Townsend’s big-eared bat was 21 years old. Townsend’s big-eared bats are one of a handful of low-intensity echolocation species colloquially referred to as "whispering bats." Two subspecies of Townsend's big-eared bat, the Ozark big-eared bat and the Virginia big-eared bat, are on the US federally endangered list.