The Mexican free-tailed bat or Brazilian free-tailed bat (Tadarida brasiliensis) is a medium-sized bat native to North, Central, and South America and the Caribbean, so named because its tail can be almost half its total length and is not attached to its uropatagium. It has been claimed to have the fastest horizontal speed of any animal, reaching top ground speeds over 99 mph (160 km/h). It also flies the highest among bats, at altitudes around 3,300 m (10,800 ft).
It is 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. For instance, up to 1.5 million bats reside under just one bridge in Austin. The Texas Legislature recognized the Mexican free-tailed bat as the "Official Flying Mammal" of the State of Texas in 1995.
