The Mexican free-tailed bat (Tadarida brasiliensis) is just one of many species of bats to inhabit the Southwest. Their fur is reddish to dark brown or gray in color. They have broad, black, forward pointing ears, and wrinkled lips. Their tails extend more than one third beyond the tail membranes; most other bats have tails that are completely enclosed within the tail membranes. Their wings are long and narrow.
Mexican free-tails prefer to roost in caves, but can also choose attics, under bridges or in abandoned buildings. They mostly roost near water, which attracts the insects they eat, as well as allowing them the opportunity to drink. Free-tail bats consume enormous amounts of moths and other insects. In the larger colonies, it is estimated that the bats can consume over 250 tons of insects in a single night.
During the winter months, the bats migrate to Mexico and Central America. In the spring, they return in vast quantities to inhabit caves all over the southwest. The largest concentration is Bracken Cave near San Antonio, Texas, where the colony numbers over 20 million. Another popular roosting point is in Carlsbad Cavern in New Mexico, but any cave or abandoned mine will do. Well, it will do for almost all the population. While most of the colonies are mixed populations of males, females and young, Orient Mine in Colorado houses only male bats. It’s the only known all-bachelor bat pad in the Southwest.