Adaptations for Flight in Bats

Flight developed independently in three groups of vertebrates. From reptilian ancestry arose the pterosaurs and the birds, and bats evolved from primitive mammals. Pterosaurs became extinct, together with their relatives the dinosaurs, more than 75 million years ago, whereas both birds and bats are still remarkably successful today. Pterosaurs probably used mostly gliding flight, but birds and bats use primarily flapping flight. Birds and bats use different styles of flight, probably as a result of the different ways in which these animals perceive their environments. Vision, which is used by birds for orientation, allows the recognition of obstacles at considerable distances. Bats, in contrast, use echolocation for orientation; this system enables primarily short-range perception of obstacles and necessitates fairly slow flight with high maneuverability. Although each group of flying vertebrates utilized somewhat different styles of flight, each met the same basic mechanical demands of flight. Each developed lifting surfaces, a means of propulsion, and each concentrated weight near the center of gravity. This paper will discuss these basic adaptations to flight as they occur in bats, and will consider selected structural and functional refinements that have served to perfect bats as flying animals. The following discussions will be based primarily on advanced members of the suborder Microchiroptera, in which the distinctive chiropteran adaptations to flight are well developed