The vocal repertoire of the black-horned capuchin (Cebus [Sapajus] nigritus): an acoustic and contextual analysis

DI BITETTI, M. S.; WHEELER, B. C.

Primatology in Argentina - SAREM Series A - Mammalogical Research - Volume 2

Sociedad Argentina para Estudio de los Mamíferos SAREM

Lugar: Mendoza; Año: 2017; p. 171 - 199

We describe the vocal repertoire of black-horned capuchins (Cebus [Sapajus] nigritus) at Iguazú National Park, Argentina, in terms of the calls' acoustic structure and the contexts in which different calls are emitted. Audio recordings of vocalizations obtained in natural contexts were supplemented with calls recorded when subjects were presented with food or predator decoys. We conducted spectrographic analysis of digitized calls to describe their acoustic structure. Multivariate analyses revealed over 30 distinguishable call types. Some of these are discrete types but other calls grade with other forms. An examination of the contexts of production provided insights into the functions of the calls. The most commonly-produced call is a ?contact note? that apparently serves to regulate within-group spacing. Two varieties of loud calls (?whistle series?) are used by lost individuals, as well as for communication between groups. Food-associated vocalizations are produced by animals feeding on clumped resources. Playback experiments showed that these calls attract listeners towards the food source. Black-horned capuchins give distinct call types to aerial and terrestrial predators; listeners respond to these different call types with predator-specific behaviors. Calls associated with terrestrial predators are frequently used in the absence of predators in a functionally deceptive manner. Vocalizations given in social contexts include several calls given by aggressors and in response to aggression, estrous vocalizations and copulation calls, vocalizations directed to newborn infants, calls that are used to coordinate group movement, and vocalizations associated with a reunion display among males. Infants appear to go through a babbling period; their calls develop into adult-like calls as they mature. The black-horned capuchin vocal repertoire is consistent with suggestions that a large number of call types are favored in closed habitats and in complex social milieus, and provides insights into some of the under-studied aspects of the socioecology of this Neotropical primate.