Bat, the only mammal capable of sustained flight. Bats are divided into two suborders—larger bats or megabats and smaller bats or microbats—and 17 families. One of these families includes all megabats (more than 150 species); the other 16 families are microbats. In all, 850 to 900 species of bats exist, far more than in any other mammalian order except the order of rodents, and bats probably exceed even rodents in total abundance.