APA Dictionary of Psychology

any call or sound produced by a nonhuman animal that can be said to communicate, that is, that can provide information about internal state or likelihood of subsequent action or can be used to assess or manage the behavior of others. Vocalizations are typically produced through vibration of an organ, such as the larynx in some mammals, the two syringes in birds, or the blowholes in whales. Frequently sounds are amplified through special organs, such as throat sacs in amphibians. See also vocal communication.