Millions of Brazilian free-tailed bats spend their summers in the southwestern United States. Gigantic colonies summer in Bracken Cave, Texas; Carlsbad Caverns, New Mexico; and even within the city of Austin, Texas, under the Congress Avenue Bridge. Learn more about the Tadarida brasiliensis, more commonly known as a Brazilian Free-tailed Bat, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.