Bearded capuchin (Sapajus libidinosus) predation on a rock cavy (Kerodon rupestris) followed by prey sharing

An exploratory study of cooperation: food-sharing behaviour in wild varied white-fronted capuchin monkeys (Cebus versicolor) in Central Colombia

Food-sharing is a cooperative behaviour related to the transfer of resources between conspecifics, and it is considered a complex prosocial behaviour because of its associated costs. It is more likely that an individual cooperates with closely related kin (e.g., in food sharing), and particularly with close maternal kin. In female philopatric species, such as Cebus spp., mother–offspring bonds likely explain patterns of maternal kin biases. On the other hand, the explanation of the evolution of food-sharing among non-kin is diverse. Capuchin monkeys (genera Cebus and Sapajus) are interesting to study cooperation since this is a critical behaviour to gain and protect ecological and reproductive resources in the wild, including care of their offspring. We performed an experimental protocol to induce behavioural observations with a provisioning technique using chicken eggs in a wild group of white-faced capuchin monkeys (Cebus versicolor). We aimed to test whether this white-faced capuchin monkeys engaged in food-sharing in the wild, describing the pattern of this cooperative behaviour. Furthermore, we also described some conditions that might affect this behaviour. We observed that these capuchins shared the eggs in passive exchanges, meaning that possessors let other individuals to eat from their egg. Our results further suggest that these exchanges may be due to mainly maternal kin biases. This study offers a preliminary observation of a little-studied capuchin species in the wild and adds information about how cooperation works in the wild.

Wild robust capuchin monkey interactions with sympatric primates

Examining interactions among sympatric primate species can provide interesting information about competition, cooperation, and avoidance between those species. Those interactions can be neutral, positive, or negative for the species involved. Capuchin monkeys are medium-sized primates that can encounter both larger and smaller primates in their varied habitats. Gracile capuchins (Cebus) are reported to present different types of interactions with other primates. Interactions with howler monkeys frequently include physical aggression, while interactions with spider monkeys are mostly threats and chases. Moreover, interaction types are not consistent across populations. Among robust capuchins (Sapajus spp.), however, no reports have been published. Here we describe and classify encounters of Sapajus libidinosus and S. nigritus with Alouatta caraya, A. guariba, Brachyteles arachnoides, and Callithrix jacchus in three sites in the environments of Cerrado, Caatinga (savannah-like), and Atlantic forest, and compare the interaction patterns among sites and different group sizes. The latter is a factor that can influence the outcome, and we expected capuchins in larger groups to be more aggressive toward other primates. Our results of 8421 h of total contact with the capuchin groups show that, indeed, capuchins in sites with larger groups presented aggressive interactions with higher frequency. However, the other species' body size also seems important as smaller primates apparently avoided capuchins, and interactions with the larger muriquis were mostly neutral for the capuchin. Capuchins showed neutral or aggressive behaviors toward howler monkeys, with differences between the rainforest and savannah groups. We found that robust capuchins can present aggressive interactions even to primates larger than themselves and that aggressive behavior was the most common response in populations living in larger groups and drier environments.