A bat hanging on the ceiling of the cave. Bats are mammals of the order Chiroptera; with their forelimbs adapted as wings, they are the only mammals naturally capable of true and sustained flight. Bats are more manoeuvrable than birds, flying with their very long spread-out digits covered with a thin membrane or patagium. The largest bats are the flying foxes and the giant golden-crowned flying fox, Acerodon jubatus. Most bats are nocturnal, and many roost in caves or other refuges. In many cultures, bats are popularly associated with darkness, malevolence, witchcraft and death. Cave wall sleeping resting hanging upside down. 4K UHD 3840×2160.