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 trigona" moths when they had the opportunity, thus refuting the hypothesis that the clicks were warning the bats of moths’ toxicity. Moth clicks also disrupted the stereotypical pattern of the bats echolocation, confirming the clicks’ jamming function. Humans may jam echolocating animals deliberately or accidentally. Recent efforts have been made to develop acoustic jamming deterrents to exclude bats from buildings or bridges, or to keep bats away from wind turbines where large numbers of mortalities occur. These deterrents have been shown to reduce bat activity over a small area. However, scaling up acoustic deterrents to large volumes for applications such