They have furry bodies and wings with no hair. Bats are the only mammals that can fly. Because they are mammals, bats are born alive. Baby bats are called pups, and have to be taken care of for an extended period of time. The females possess mammary glands where milk is produced to feed the young.
Bats have arms, wrists, and hands with a thumb and four fingers.
The bones of the hands and fingers are very long and form the structure of the wing. Their wings are really webbed hands. Thin, elastic skin stretches right across their very long fingers to their hind legs. There are over 950 different kinds of bats. They vary greatly in size, color and habits.