High-speed photograph of a fruit bat (sub-order: Megachiroptera) in flight. Bats are the only mammals truly able to fly, with their front limbs elongated as supports for the membrane (patagium) which originates on both sides of the body as a continuation of the epidermis, pigment layer & corium. The elastic membrane is interlaced with fine muscle fibres, nerves & blood vessels. Wing motion during flight is in an elliptical pattern of rotation, with the down stroke from high at back to low in front. Frequency of strokes for a large fruit bat is 10-12 per second (smaller insectivorous bats may perform 18 per second).