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
Human echolocation It had seemed that he would become a successful flautist until he had to give up playing music in 2005. De Witte has been completely blind since 2009 due to additional problems with his eyes. He was taught echolocation by Daniel Kish and was given the nickname "Batman from Belgium" by the press. Scadden has written of his experiences with blindness. He was not born blind, but lost his sight due to illness. As a child, he learned to use echolocation well enough to ride a bicycle in traffic. (His parents thought that he still had some sight remaining.) He