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
Bats of Canada their ability to fly, and rarely become aggressive. Careless handling of bats is the main cause of rabies transmission, which has resulted in five human cases in Canada since 1925. Fewer than 2% of bats in Canada are rabid, 95% of which are big brown bats. Testing bats for rabies is usually performed by the Canadian Food Inspection Agency. Inhalation of dusty bat manure may result in histoplasmosis, which will present as a mild respiratory infection. There are no pesticides that may be used on bats in Canada. In 2011, the Nature Conservancy of Canada received a $50,000 grant from