A statewide summer resident of Arizona, the Mexican, Brazilian or American free-tailed bat occurs south through Central America and tropical South America. This is a highly colonial species with some colonies numbering in the millions. The Mexican free-tailed bat is an inhabitant of mines, caves, buildings and bridges.
Females are apparenly already pregnant when they come into Arizona in the spring.
While winter records exist for this bat in Arizona, there are no records of this species hibernating Arizona. The Mexican free-tailed bat is a highly migratory species with much of the United States population going south to hibernate. Most banding studies have shown that those from eastern and central Arizona travel about 600 miles to spend the winter in Sonora and Sinaloa, Mexico. These bats are high flying foragers, leaving their roost en masse to forage up to 40 miles away. It appears that the population numbers of this species have declined across its range.