A medium-sized bat that is native to the Americas, regarded as one of the most abundant mammals in North America. Its proclivity towards roosting in huge numbers at relatively few locations makes it vulnerable to habitat destruction in spite of its abundance. The bat is considered a species of special concern in California as a result of declining populations. It has been claimed to have the fastest horizontal speed of any animal, reaching top ground speeds of over 100 mph. They roost primarily in caves. However, they will also roost in buildings of any type as long as they have access to openings and dark recesses in ceilings or walls. The bats can make roosting sites of buildings regardless of "age, height, architecture, construction materials, occupancy by humans and compass orientation".
Mexican free-tailed bats are nocturnal foragers and begin feeding after dusk. They travel 50 km in a quick, direct flight pattern to feed. This species flies the highest among bats, at altitudes around 3300 m.
