A small fold, or "pocket" in the wing membrane of the free-tailed bat, near its knee, gives this bat its common name. Pocketed free-tailed bats have large ears and long wings, and fly rapidly, generally pursuing insects on the wing. Learn more about the Nyctinomops femorosaccus, more commonly known as a Pocketed Free-tailed Bat, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.