Townsend’s Big-eared Bat, Corynorhinus townsendii

Townsend’s big-eared bat (Corynorhinus townsendii) is one of a large number of species in the vesper bat family. It is found in Mexico, Canada, and the United States. The habitats of these bats include abandoned buildings and mine tunnels and caves. There are three recognized subspecies of the Townsend’s big-eared bat.

The Townsend’s big-eared bat has an average body length of four inches with a wingspan of up to eleven inches. The body weight of this medium sized bat averages between .2 to .4 ounces. It has exceptionally long ears that are flexible. The color of the Townsend’s big-eared bat varies from each part of the body, consisting of shades of brown. Although the browns are slightly different, this bat can be recognized by its virtually uniform body color.

Fall is mating season for the Townsend’s big-eared bat, and males will perform the courtship rituals. As with many bats, the female stores the male’s sperm in her reproductive tract until spring, and the baby is born fifty to sixty days later. Ninety percent of female big-eared bats are able to reproduce, and each mother can have one pink, hairless pup a year. Females and males will roost separately throughout the summer, and females will form “maternity colonies” that can consist of twelve to two-hundred adult bats and pups. In the United States, colonies of over one thousand bats have been found.

Hibernating during the winter occurs in packed groups, with males hibernating in warmer areas than females. They tend to wake easily, and can be seen moving from one cave to another, or to different areas of one cave. Big-eared bats will tightly group together, which may help maintain body heat. These bats will eat as much as they can and increase their body weight before they go into hibernation. Their diet can comprise of moths, sawflies, dung beetles, lacewings, and other small insects. The lifespan of Townsend’s big-eared bats can reach up to sixteen years, and they have a conservation status of least concern.

Image Caption: Big eared townsend bat (Corynorhinus townsendii). Credit: Wikipedia