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
Crawford's gray shrew Instead, it builds small nests in pack rat houses or under dead agaves. This species also conserves water by being nocturnal, unlike other shrews, which hunt day and night to avoid starvation. Crawford's gray shrew has poor vision, so it uses its highly sensitive ears and long nose to hunt down its prey. It will also use an echolocation, similar to bats, with high-pitched squeaks to locate prey. It will also store food during the night so it will not have to go out during the day. To keep from losing any water from its victims, it will bite off