Facial Displays in Young Tufted Capuchin Monkeys (Cebus apella): Appearance, Meaning, Context and Target

Abstract

Facial displays are important for communication, and their ontogeny has been studied primarily in chimpanzees and macaques. We investigated the ontogeny, communicative function and target of facial displays in Cebus apella. Our results show that facial displays are absent at birth and develop as infants grow older. Lip-smacking appears first (at about 1 month of age), followed by scalp-lifting, relaxed open-mouth, silent bared-teeth, open-mouth silent bared-teeth displays and finally the open-mouth threat face. Infants perform most facial displays in the same contexts as adults, with the exception of the silent bared-teeth display that young capuchins use primarily, or exclusively, in affiliative contexts. Interestingly, facial displays are exchanged very often with peers, less frequently with adults and almost never with the mother.

The Repertoire and Social Function of Facial Displays in Cebus capucinus

“…It is directed almost exclusively toward infants and juveniles; it is bidirectional, but often it is not reciprocated. In general, non-kin and far-kin exchange more lip-smacking displays than close-kin do, as in tufted capuchins (De Marco and Visalberghi 2007). Among white-faced capuchins, the mother is the partner that exchanges the smallest number of lipsmacking displays with her offspring.…”

“…Moreover, white-faced capuchins do not perform the scalp-lifting display (a quick raising of the scalp and the eyebrows) or exhibit movements of the scalp in association with other facial displays. Contrarily, scalp-lifting is one of the most common displays characterizing sexual behavior in tufted capuchins (Carosi and Visalberghi 2002), and scalp retraction often occurs in association with other facial displays (De Marco and Visalberghi 2007;Visalberghi et al 2006). For example, during threat displays tufted capuchins raise their eyebrows dramatically, whereas white-faced capuchins lower them into a mild frown (Freese and Oppenheimer 1981).…”

“…Researchers had not reported lip-smacking in white-faced capuchins (Oppenheimer 1973), in contrast to tufted capuchins (Weigel 1979;Visalberghi et al 2006;De Marco and Visalberghi 2007), probably because it is not easy to observe in white-faced capuchins, which perform it in a very mild form, typically when very close to their partners. In primates, the lip-smacking display may occur in a very wide variety of social circumstances, including grooming, copulation, greeting, and antagonism (Redican 1975).We noted that in white-faced capuchins lip-smacking conveys a positive message and promotes affiliative interactions.…”

“…The researchers who have investigated the repertoire of facial displays of Cebus have studied C. apella (De Marco and Visalberghi 2007;Visalberghi et al 2006;Weigel 1979), while systematic studies on facial communication in C. capucinus are very limited (Oppenheimer 1973). Although Weigel (1979) argued that all capuchin species are similar in their visual repertoires of signals, their great morphological variability suggests that morphological differences in facial displays could exist.…”

Monkey drumming reveals common networks for perceiving vocal and nonvocal communication sounds

“…That the subjects took the experimental setting for real is demonstrated by their spontaneous use of behaviorally relevant expressions. Many subjects attempted to communicate with the individuals shown onscreen, as demonstrated by social gestures like lip smacking (25)(26)(27). Indeed, lip smacking was more frequent during the presentation of drumming sounds (total time of lip-smacking across all animals tested: 240.57 s for drumming sounds and 180.85 s for cage sounds), suggesting that listeners escalate their affiliative and appeasing gestures to offset the threat signaled by drumming.…”