The vocal repertoires of the bush dog (Speothos venaticus), crab-eating fox (Cerdocyon thous), and maned wolf (Chrysocyon brachyurus)

The vocalizations of the bush dog (Speothos venaticus), crab-eating fox (Cerdocyon thous), and maned wolf (Chrysocyon brachyurus) were studied in a captive setting. The three species' repertoires were similar and included whines, long-distance calls, and growls. The whines and growls varied in amplitude, duration, and repetition rate; these variations and the frequencies of occurrence probably were influenced by both social organization and habitat characteristics. The bush dog, which lives in family groups and inhabits rain forests, had an elaborate whine-scream continuum that at close distances conveyed a wide range of moods. On the other hand, the maned wolf, which is solitary and frequents open pampas, used amplitude variations of the growl to signal hostile intentions over short, medium, and long distances.The long-distance vocalizations of the three species were the least variable in structure; the bush dog and crab-eating fox used the call to promote contact with separated pairmates or family members. Based on recordings during development, these two calls appeared to arise from the repetitive whine, a variant of the basic whine syllable. The maned wolf also had a contact-promoting howl, apparently an extended whine of high amplitude, but it was rarely recorded during the present study. More prominent was the maned wolf roar-bark, which functioned to space individuals over large distances, and appeared to be a growl of high amplitude.