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
Daubenton's bat also always near water. Daubenton's bat hibernates in the same type of locations from September to late March or April. Daubenton's bat is insectivorous and uses echolocation to find prey and orient itself at night. Bats emit sounds too high in frequency for humans to detect, and interpret the echoes created to build a "sound picture" of their surroundings. Daubenton's bat emits echolocation calls at frequencies between 32 and 85 kHz, though typical calls peak at 45 to 50 kHz; the calls have a duration of 3.3 ms. The bats emerge at twilight to hunt for insects over the water.