Behaviour 2019
Associated Emotional Expressions in Capuchin Monkeys
Natalia Albuquerque, Marina Belli, Ana Clara Varella, Patrícia Izar. Institute of Psychology, University of Sao Paulo, Sao Paulo, Sao Paulo, Brazil

Primates present a rich repertoire of facial expressions that are used in a variety of contexts, ranging from externalizing motivations to communicating ecologically relevant information. In fact, more than one facial expression may be displayed at the same time. However, the role of such elaborate emotional tactic is still unclear. During lipsmacking (LS), monkeys often use this strategy. Aiming at unfolding the function of these combined expressions, we investigated 94 events of LS displayed towards four 2-month-old bearded capuchin monkeys from a wild population of Brazil. We also coded emotional displays (ED; tongue protusion, tongue out, open mouth, scalp lifting). LS showed a mean of 4.6±6.1 seconds and ED 0.13± 0.25 seconds. We used a GLMM, including infant as random factor, LS as dependent variable and ED as fixed factor (regressor), and we found a significant positive relation (F1,94=2.636; p=0.001) between ED and LS. Even though these associated ED occur only for around 3% of the duration of LS, they contribute to the maintenance of the behavior. Moreover, it is possible that these ED may be related to a greater emotional engagement during the interaction with the infant.