Townsend's Big-eared Bat

Townsend's Big-eared Bat

Phylum : Chordata
Class : Mammalia
Order : Chiroptera
Family : Vespertilionidae
Genus : Corynorhinus
Species : C. townsendii 

Body Length : 4in (10cm)
Wingspand : 11in (28cm)

IUCN Status : Least Concern

The ears of a Townsend's Big-eared Bat can grow as long as 2.5cm, which is astounding considering that that is 25% of their body length! These flying mammals can be found throughout western North America, ranging from southern Canada down into Mexico.

Townsend's Big-eared bats are phenomenal fliers, and feed almost exclusively on moths that they pick off of trees. Echolocation and low frequency sounds play a major role in their hunting and bat-to-bat communication. They are able to receive sound thanks to their massive ears, that they can swivel about to focus in on moving targets. Young bats also make unique chirping calls that their mothers use to locate them.

Mating takes place in the fall, and fertilization is delayed until the following spring. Females group up into maternity colonies at that time, and these groups can number over 1,000 bats! They each give birth to only one pup at a time, and infants are quite large, up to 25% of the mothers size. The species is rather long lived if the pups can survive their first year. Adults as old as 30 have been identified.

During the winter Townsend's Big-eared Bats go into hibernation, and during warmer months they often go into torpor when the temperate cools.

The species overall is not threatened, though localized populations  have had their numbers reduced due to habitat loss, pesticides, and disturbance of hibernation sites. Some subspecies, including Ozark and Virginia Big-eared Bats, are federally endangered.