Mammals
Western Mastiff Bat
Eumops perotis · also called greater mastiff bat
As dusk falls over a desert canyon, a western mastiff bat drops from a high cliff crevice and starts to fly, a bat big enough that its calls can sometimes be heard by human ears.
Overview
The western mastiff bat, Eumops perotis, is a Least Concern bat of the deserts and rocky canyons of the southwestern United States and Mexico. Its large size, audible calls, and need for high cliff roosts make it the most imposing bat in North America.
A bat that needs height
To take off, the western mastiff bat needs to drop from a high perch, so it depends on tall cliffs and rock faces for its roosts.
Status
Least Concern, widespread but uncommon and dependent on a limited number of roosts.
Western Mastiff Bat: common questions
How big is the western mastiff bat?
It is the largest bat in North America, with a wingspan of around half a metre.
Can people hear the western mastiff bat?
Its echolocation calls are pitched low enough that people can sometimes hear them.
Why does it roost high on cliffs?
It needs to drop from a high crevice to gain flying speed.
Where is the western mastiff bat found?
It lives in desert, scrub, and rocky country in the southwestern United States and Mexico.