This tendency to form and maintain herds suggests that some degree of communication occurs between individuals. This may well be auditory in nature. Australian aboriginals report the presence of “whistlers” whom they regard as dominant individuals. These animals are considered to control herds and have been named for the sounds they apparently emit. Sounds have been recorded from the dugong (see Addendum).
The Florida manatee (7’richechus manatus latirosb-is) produces fundamental tones that are mostly 2.5-5 kHz. They may be as low as 0.6 kHz and as high as 16 kHz (Schevill & Watkins, 1%5). The Amazonian manatee (Z’richechus inunguis) is known to emit sounds with a fundamental frequency between 6 and 8 kHz (Evans & Herald, 1970) (see Addendum).