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General Information

Habitat and Diet

Social Spacing

Foraging Behavior

Social Group

Mating Behavior

Grooming Behavior and Cooperative Altruism

Maternal Care and Alloparenting

References

Capuchins live in multi-male, multi-female groups of 8 to 14, consisting of adult females and their offspring, one breeding male and several nonbreeding subadult and (rarely) adult males (O’Brien and Robinson, 1993; Jolly, 1985). DiBitetti (1997) suggests that a group of non-tufted capuchins could be as large as 30 individuals. There is usually a 1:1 ratio of males to females, with the one breeding male serving as the dominant member of the group. The sex ratio may differ as a result of late maturation among male juveniles, resulting in more males than females within the group. Upon reaching maturity, male capuchins migrate directly from their natal group to another; solitary individuals are infrequent among the capuchin monkey (Robinson and Janson, 1987). Despite the fact that they live in mixed-sex groups, females form the core of the group because they remain in their natal groups and develop female-bonded groups (www.wellingtonzoo.com).

Capuchin monkeys are organized based upon a linear dominance hierarchy that is determined by size among males and by matrilineal inheritance for females (O’Brien and Robinson, 1993; Silk, 1993). Each capuchin group is lead by a dominant male who protects the rest of the group from predators and other monkey groups and controls access to food resources through methods of aggression (DiBitetti and Janson, 2001). The dominant male alerts the rest of the group of the presence of a predator by sending alarm calls that the subordinates answer by following suit behind the dominant male to drive the predator out of their home range. In all Cebus species, the dominant male gets the first choice in both feeding and mating while the subordinate males wait for their turn to feed (animaldiversity.ummz.umich.edu). However, the C. apella is the least aggressive towards other monkey species than other species of Cebus as C. apella often are found feeding with spider monkeys.

Stable linear dominance hierarchies are found only in species that form female-bonded groups, such as the capuchin (Silk, 1993). Welker, Höhmann, Schäfer-Witt (1990) found the presence of matrilines within their colony of capuchin monkeys that they established. It is suggested that individuals within a matriline support each other during aggressive encounters and aid in raising each other’s offspring (Welker et al, 1990). The dominant female of a group oftentimes forms a coalition with high-ranking juveniles, who gain their dominance based on age, not aggression. Coalitions usually form according to the matrilineal lines, as dominant females will form coalitions with their sister and/or daughter (O’Brien and Robinson, 1993). As a result of her central position within the group, the dominant female is often the only female nearby when a juvenile needs support. When conflict arises between two juveniles, the higher-ranking juvenile will receive support and assistance from older females within his or her coalition while the lower-ranking juvenile is not supported (O’Brien and Robinson, 1993). Dominant individuals (no matter their age) are highly valued as reciprocators, so would more likely receive aid from subordinate, non-matrilineal members. The reciprocal altruism displayed by lower ranking matrilineals is thought to be a major factor maintaining the high rank in a matriline over stable periods. Matrilineal power is primarily impelled by the number of females in the matriline. This factor also predicts matrilineal rank in newly structured matrilineal dominance hierarchies. Rank order is established by age among juveniles and since there is such an elongated interval between births (24 months), it is rare for kin to be infants at the same time (O’Brien and Robinson, 1993). Thus, related juveniles will be close in rank, as it is inherited matrilineally. Inheritance of matrilineal rank seems to be an evolutionarily stable strategy adapted to a set of ecological and social situations requiring the prominence of large groups, including related and unrelated females, and a positive correlation between reproductive success and dominance rank

Intergroup relations are relatively civil among the four species of capuchin monkeys, as conflicts usually involve the adults and subadult males within the same species. All members of the group play a role in resource defense, yet intergroup conflict increases when resources are concentrated as opposed to abundantly scattered (Robinson and Janson, 1997). In brown capuchins, intergroup conflict arises when multiple groups are foraging in or near fruit trees, as this is the primary (and most desired) resource of all of the capuchins. Agonistic interactions within a group occur predominantly between the dominant male or the dominant female (Robinson and Janson, 1997).