Food-associated calls in capuchin monkeys (Sapajus libidinosus): research on casual factors and function

Author(s)

Luíza Gonzalez Ferreira

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Psicologia (IP/SBD)
• Defense date: 2016-03-03

Examining board members

Patricia Izar Mauro; Nicolas Gerard Chaline; Rogerio Grassetto Teixeira da Cunha

• Advisor: Patricia Izar Mauro

Abstract

Resource competition among animals can occur directly, through monopolization, or indirectly, through depletion. Communicative signals in competition contexts can regulate competition by manipulating behaviour of other individuals. Primate species that forage in stable and large groups, which experience intense food competition, may decrease food competition through food calls, which indicate either the willingness to be approached by other individuals or to announce the ownership of food, both decreasing the aggression against the caller. Alternatively, food calls may enhance the callers reputation. Capuchin monkeys emit different types of food calls according to food distribution in the habitat, decreasing or increasing the distance between individuals, which suggests the emission of specific vocalizations regulates each type of food competition. The aim of this study was to investigate the occurrence and the function of food-associated calls emitted by a group of capuchin monkeys (Sapajus libidinodus). Data were collected in Fazenda Boa Vista, Piauí, a transition between Cerrado and Caatinga. The characteristics of the caller, of the food resource and of the social context during a feeding bout were recorded according to focal animal method (60 minutes). In clumped resources, resource size and quantity of food were also registered. Vocalizations were continuously recorded during each focal and classified as: chihui, chihui2, contact note, grgr and FAWS. The probability of calling was higher in feeding contexts than in other contexts and, among the feeding contexts, FAWS and grgr calls were associated to provisioned and clumped foods and chihui was weakly associated to clumped foods and also emitted in forage context. FAWS and grgr calls had a higher probability of emission by subordinate individuals, in resources with a large quantity of food, and when the caller had a large number of neighbors. These vocalizations were emitted, then, in intense contest competition, in sources with low proportion of food, therefore, when sharing food would not be so costly for the caller, supporting the hypothesis of regulating contest competition by decreasing the probability of aggression. Chihui calls had a higher probability of emission in scramble and contest competition, in sources with medium quantity of food, which the proportion of consumed food is high, therefore, when sharing food would be more costly. The number of neighbors and the presence of dominant individuals did not affect the probability of call. These results support the hypothesis that food calls decrease scramble and contest competition by increasing interindividual distance. These results suggest that capuchin monkeys can regulate each type of food competition through different types of food calls (AU)

• FAPESP's process: 13/13226-7 - Food-associated calls in capuchin monkeys (Sapajus libidinosus): research on casual factors and function
• Grantee: Luíza Gonzalez Ferreira
• Support Opportunities: Scholarships in Brazil - Master