There are winter records only from southern Arizona, California, and Texas. The ears are large and rounded, and the upper lips have numerous vertical wrinkles. It is common in southern and southwestern U.S. and north to Nebraska, Colorado, Utah, Nevada, and Oregon. Mexican free-tailed bats may form nursery colonies that include anywhere from a few hundred to several million bats. Nursery colonies are found in caves, under bridges, and in buildings.
Males form smaller bachelor colonies.
These bats also use bat houses. They are not capable of true hibernation and most western populations migrate to caves in Mexico and Central America during the winter, although some colonies overwinter in buildings or bat houses in warmer sections of their range. Populations in the southeastern U.S. remain active in the area year round. Absolutely no rights of distribution by sale or other transfer of ownership or by rental, lease or lending, preparation of derivative works, or reproduction, in whole or in part, is granted. BCI reserves the rights to actively protect against infringement.