Bats are mammals of the order Chiroptera (/kaɪˈrɒptərə/; from the Greek χείρ - cheir, "hand" and πτερόν - pteron, "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, can only glide for short distances. Bats do not flap their entire forelimbs, as birds do, but instead flap their spread-out digits, which are very long and covered with a thin membrane or patagium
Bats are placental mammals. Bats were formerly thought to have been most closely related to the flying lemurs, treeshrews, and primates, but recent molecular cladistics research indicates that they actually belong to Laurasiatheria, a diverse group also containing Carnivora and Artiodactyla.
The two traditionally recognized suborders of bats are:
Microbats use echolocation; with the exception of the genus Rousettus, megabats do not.
Microbats lack the claw at the second finger of the forelimb.
The ears of microbats do not close to form a ring; the edges are separated from each other at the base of the ear.
* Microbats lack underfur; they are either naked or have guard hairs.