Bats are the only mammals capable of true flight. They have membranes between the toes of their forefeet. The toes are very long, which gives the hand the look of a wing. They have no feathers, just bare skin.
Most bats feed on small insects, some eat fruits. Some tropic bats feed the blood of other mammal, like cows. This is very rare, but so strange, that it may have be the seed of the connection vapires-bats.
Bats live in very large families. In Carlsbad Cavern the amount of bats is exremely high, the sky darkens when thy leave the cave entrance in the dusk.
Bats hunt at night. At day theay sleep in caves, hollow trees and the roofs of old houses. But at night they hunt insects. They orientate with a unique sonic system. Their nose is able to produce ultrasonic impulses. The big and very sharp ears are able to hear the echo of objects. So the bats are able to orientate in absolute darkness.
But the sounds has an additional function: The unique sound of every bat allows the mothers to find their child in a family of ten thousands of bats when she comes back from the hunt!