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
Shrew orientation. In contrast to bats, shrews use echolocation only to investigate their habitats rather than additionally to pinpoint food. Except for large and thus strongly reflecting objects, such as a big stone or tree trunk, they probably are not able to disentangle echo scenes, but rather derive information on habitat type from the overall call reverberations. This might be comparable to human hearing whether one calls into a beech forest or into a reverberant wine cellar. The 385 shrew species are in 26 genera, which are grouped into three living subfamilies: Crocidurinae (white-toothed shrews), Myosoricinae (African shrews) and Soricinae (red-toothed