Animal echolocation in the external ear. There are two hypotheses about the evolution of echolocation in bats. The first suggests that laryngeal echolocation evolved twice in Chiroptera, once in the Yangochiroptera and once in the horseshoe bats (Rhinolophidae). The second proposes that laryngeal echolocation had a single origin in Chiroptera, was subsequently lost in the family Pteropodidae (all megabats), and later evolved as a system of tongue-clicking in the genus "Rousettus". Individual bat species echolocate within specific frequency ranges that suit their environment and prey types. This has sometimes been used by researchers to identify bats flying in an area simply by
Bulldog bat are long and narrow and their ears are large and funnel shaped. Unusual among bats, they have cheek-pouches for storing food. They also have full lips divided by a fold of skin giving a 'hare lip' look which together with the cheek pouches gives them their bulldog-like appearance. The species of lesser bulldog bats are insectivorous and whilst the greater bulldog bats also eat insects their chief food is fish. They use their echolocation to pinpoint the ripples they make on the surfaces of water. The greater bulldog bat trawls the water with its long, curved talons approximately 2–3 cm