How do bats fly?

Bats fly using powered flight with wings that are very different from birds' wings, making them the only mammals capable of true sustained flight. A bat's wing is made of a thin, flexible membrane called patagium stretched between greatly elongated finger bones, similar to a human hand with long fingers, with the thumb being short and clawed for climbing. The membrane is supported by the second to fifth fingers and extends to the legs and tail, forming a large surface area for lift. Bats generate lift and thrust by flapping these wings with powerful chest muscles, and they can control flight with incredible agility by adjusting wing shape, tension, and angle, allowing them to turn sharply, hover briefly, and catch insects in mid-air. Unlike birds that flap mainly up and down, bats use complex wing motions that include folding and unfolding during each stroke. They also use their tail membrane called uropatagium for steering and catching insects. Bats take off by dropping from a roost or launching from a height because their wings cannot generate enough lift from the ground alone. Some larger fruit bats can take off from the ground with a jump. Their flight is highly maneuverable, allowing them to navigate through dense forests and catch insects using echolocation to detect prey while flying in complete darkness at speeds up to 20 to 60 miles per hour depending on species.