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
Echolocation jamming produce ultrasonic clicks in response to the echolocation calls bats use while attacking prey. For most species of tiger moth these clicks warn bats that the moths have toxic compounds that make them distasteful. However, the tiger moth "Bertholdia trigona" produces clicks at a very high rate (up to 4,500 per second) to jam bat echolocation. Jamming is the most effective defense against bats ever documented, with jamming causing a ten-fold decrease in bat capture success in the field. The possibility that moths jam bat echolocation arose with an experiment report published in 1965 by Dorothy Dunning and Kenneth Roeder.