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
Egyptian slit-faced bat a few to thousands of other members. Because they can maneuver in crowded habitats, they are able to occupy caves and holes that cannot be accessed by other bat species. While the bats do form a communal roost, individuals do not huddle together to conserve energy and warmth. They occupy two roosts, using the daytime roost to rest, while only spending a few hours in the night roost before going out to forage. They have a long-night foraging period, lasting several hours. The bats use high-frequency and low-intensity echolocation calls to locate prey. The low wing loading and low aspect