Egyptian fruit bat their days roosting in trees or caves, often with large groups of other bats, sometimes numbering in the thousands. They emerge from the roost to forage for food in the late evening, and return just before dawn. They hang upside down, with their wings folded closely around their bodies. Egyptian fruit bats, along with other species in the genus "Rousettus", are the only megachiropterid bats to use echolocation, which they accomplish by emitting a series of sharp clicks with their tongues. The clicks are normally slow and constant, but these clicks speed up dramatically when the bats approach an object.
Animal echolocation be received though fatty lobes surrounding the ears with a similar density to water. Some researchers believe that when they approach the object of interest, they protect themselves against the louder echo by quietening the emitted sound. In bats this is known to happen, but here the hearing sensitivity is also reduced close to a target. Oilbirds and some species of swiftlet are known to use a relatively crude form of echolocation compared to that of bats and dolphins. These nocturnal birds emit calls while flying and use the calls to navigate through trees and caves where they live. Terrestrial