Big Brown Bat, Eptesicus fuscus

The big brown bat (Eptesicus fuscus) is a vesper bat that can be found in many areas including Canada, Colombia, Guatemala, Jamaica, Panama, and the United States. It can be found roosting in many areas including tree hollows, caves, barns, abandoned buildings, and window shutters. It is thought that these bats prefer to roost in natural structures like caves for the winter. During this time, the bats will hibernate, but if the weather is warm, flying about and even breeding can occur. There are two subspecies currently recognized under this bat, both occurring in the United Sates.

The big brown bat can reach an average body length of up to five inches, with a wingspan of up to thirteen inches. The long fur is typically tan or light brown in color, while the wings, face, ears, and feet are darker brown in color. It can emit clicking noises while in flight that are distinct from echolocation calls.

The mating season for the big brown bat occurs between the months of November and March. Females will form a maternity colony at the end if the breeding season, separating from the males. The diet of the big brown bat consists of insects like beetles, moths, and wasps. These are caught in flight, giving the bats an erratic flight pattern when hunting.  The big brown bat appears on the IUCN Red List with a conservation status of “Least Concern”.

Image Caption: Big brown bat (Eptesicus fuscus). Credit: NPS/Wikipedia