Abstract # 92:

Scheduled for Thursday, August 18, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

A frog in the throat: The “gargle” vocalization of immature white-faced capuchin monkeys (Cebus capucinus) in Costa Rica

K. C. MacKinnon
Saint Louis University, Dept. of Sociology and Criminal Justice, and Center for International Studies, Saint Louis University, 3500 Lindell Blvd., St. Louis, MO 63103, USA
     The gargle vocalization is a unique call in capuchins. It is a raspy, throaty noise made by immatures, usually directed towards an adult male, particularly the alpha. This presentation examines the context of gargle vocalizations in infant (birth-1 year) and small juvenile (1-3 years) white-faced capuchin monkeys (Cebus capucinus) in northwestern Costa Rica. Data were collected for 11 months on two habituated groups of capuchins using focal animal sampling, and immatures were recognized individually. Immatures directed virtually all of their gargle vocalizations to adult males, and almost exclusively to the alpha male. In paired comparisons (two-tailed Mann-Whitney U tests), small juveniles gargled to adult males significantly more than to adult females (U = 0.0, W = 36, P = 0.0022), and among males, juveniles gargled to the alpha significantly more than to the beta (U = 0.0, W = 24, P = 0.0095). The calls elicited no discernable responses in the adult males, and males were not observed gargling towards any group members. Immatures, particularly small juveniles, are highly aware of the actions of alpha males, and visually monitor, follow, and often approach them. The function of this call may serve to ‘announce’ the approach of a younger, submissive individual, thereby guarding against any possible negative reaction by the adult male. Capuchin males are quite tolerant of immatures, and this call may facilitate affiliative interactions.