Vertebrate Predation and Food-Sharing in Cebus and Pan

Capuchins and chimpanzees are the only nonhuman primates apart from baboons known to prey systematically upon relatively large vertebrates. Vertebrate predation is common and well documented in Pan troglodytes, rare in Pan paniscus, and commonly reported but infrequently studied in Cebus. Food-sharing is common in both Pan species but rarely reported for wild capuchins. I present data on vertebrate predation and food-sharing by white-faced capuchins (Cebus capucinus) from ongoing field studies at Santa Rosa National Park, Costa Rica. We have observed 106 successful predation events resulting in the capture of 156 prey items during 2929 observation hr (5.35 prey per 100 hr). Squirrels and nestling coatis comprised half of the prey taken; the remainder were mainly nestling birds and eggs. Adult males took 52% of all prey and 67% of squirrels. Squirrels are actively hunted and about 65% of them are adults. I estimated that the average capuchin group kills 43–50 squirrels annually, mostly during the dry season. Capuchins hunt squirrels in groups 81% of the time, and 17% of hunts are successful. There is no evidence for cooperative hunting, but occasional collaboration is suggested. Rates of food-sharing were low (1.7 per 100 hr), and meat was the only food shared between adults. I compare predation and food-sharing in C. capucinus with published data for Pan troglodytes, primarily in Gombe and Taï National Parks. I discuss sex differences, hunting strategies, the relationship between hunting and food-sharing, and various ecological and social factors that may promote vertebrate predation in Pan and Cebus.     

The use of naturally-occurring copper and iron tools by monkeys: Possible implications for the emergence of metal-tool technology in hominids

This research examined the use of naturally-occurring metal tools by monkeys. We presented groups of capuchins (Cebus apella) with copper nuggets and apparatus that accommodated the use of tools to crack open nuts and penetrate barriers. Six of fourteen monkeys placed copper nuggets in forceful contact with hard surfaces. Five of these animals used copper nuggets to crack open nuts and penetrate acetate. In follow-up tests capuchins preferred stone tools over copper tools, and used an iron meteorite as a multi-purpose tool. We hypothesize that human metal-tool technology probably came about as a consequence of existing stone-tool practices.     

Grooming,rank, and agonistic support in tufted capuchin monkeys

Studies investigating the relation between allogrooming and social rank in capuchin monkeys (genus Cebus) have yielded inconsistent results. In this study, we investigated the relation between grooming, agonistic support, aggression and social rank in a captive group of tufted capuchin monkeys (C. apella). Differently from most previous studies, we based our analyses on a relatively large database and studied a group with known genealogical relationships. Tufted capuchin females did not exchange grooming for rank‐related benefits such as agonistic support or reduced aggression. Coherently with this picture, they did not groom up the hierarchy and did not compete for accessing high‐ranking grooming partners. It is suggested that a small group size, coupled with a strong kin bias, may make the exchange of grooming for rank‐related benefits impossible or unprofitable, thus eliminating the advantages of grooming up the hierarchy. We provide several possible explanations for the heterogeneity of results across capuchin studies that have addressed similar questions. Am. J. Primatol. 71:101–105, 2009. © 2008 Wiley‐Liss, Inc.     

Postnatal growth allometry of the extremities in Cebus albifrons and Cebus apella: A longitudinal and comparative study

Cebus albifrons and Cebus apella, partially sympatric capuchin monkeys from South America, are known to differ substantially in adult body mass and bodily proportions. C. apella possesses a robust, stocky build in contrast to the more gracile, relatively longer limbed body design of C. albifrons. Average birth weights and adult body lengths of these two congeners, however, are remarkably similar and do not serve to distinguish them. This study examines longitudinal growth rates and patterns of ontogenetic scaling in the extremities (humerus, radius, hand, femur, tibia, foot) in order to document the nature and magnitude of skeletal changes associated with increasing age and body mass. Our data indicate that the growth rates of the six skeletal components of the limbs differ only slightly and somewhat inconsistently between the two species. Body mass, however, increases at a consistently faster rate in C. apella. Relative to body mass, therefore, the extremities of C. albifrons scale much faster than those of C. apella. This implies that at any given postnatal body mass, C. albifrons is longer limbed than C. apella. Conversely, C. apella is heavier than C. albifrons at any given limb length or age. We suggest that such differences in body mass distribution are causally related to differences in locomotor behavior and foraging strategies. Specifically, the relatively long-limbed C. albifrons is probably more cursorial and tends to travel longer distances each day than C. apella. C. apella is a much more deliberate quadruped and is also characterized by especially vigorous and powerful foraging and feeding behaviors. We also compare our results to other (mostly cross-sectional) studies of skeletal growth allometry in nonhuman primates.     

Development of activity patterns,social interactions,and exploratory behavior in infant tufted capuchins (Cebus apella)

Early organization of activity states was studied in 17 tufted capuchin (Cebus apella) infants from birth to 11 weeks of age. Development of exploration and interactions with mothers and other group members were studied in 14 of these infants up to the age of 1 year. Activity profiles changed from 3 to 8 weeks as infants began to move off mothers and explore their environments. From 2 to 6 months time with mothers decreased; time alone increased correspondingly. Time spent with other group members did not vary significantly over the first year. By 7–9 months capuchin infants spent more time alone or with other group members than with mothers, although weaning was still not completed by the end of the first year. Simple environmental exploration began in the 2nd month and reached stable levels by 4 months. Complex manipulation of food and objects first began at 3–4 months and increased to stable levels in the second half of the first year. Some preliminary differences were evident between infants living in indoor cages and those living in indoor/ outdoor runs. Infants in cages spent less time in dorsal contact with mothers, and less time in social play and proximity to other animals than those in runs. Instead, infants in cages spent more time alone and engaged in more manipulation of food. Some measures of social and exploratory behavior showed a high degree of variability which may be useful in exploring individual differences in infant temperament or reactivity. © 1995 Wiley-Liss, Inc.     

Schistosoma haematobium: experimental infection in capuchin monkey, Cebus apella

South American capuchin monkeys (Cebus apella) have been included in a series of nonhuman primates under evaluation for their potential use as models in a study of the basic biology of Schistosoma haematobium. Emphasis has been given to involvement of the urogenital system, a prominent feature of infection in man. Preliminary observations on Cebus apella with moderate numbers of S. haematobium from Iran showed that there may be serious involvement of the urogenital system with development of pronounced hydronephrosis accompanied by pathobiological alteration of the urinary bladder, ureters, and kidneys. There were heavy deposits of parasite eggs in the major viscera.     

Cross-genus adoption of a marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus): case report

We report a case of interspecies adoption of an infant marmoset (Callithrix jacchus) by wild capuchin monkeys (Cebus libidinosus). The marmoset was an infant when it was first observed in the capuchin group on 3 March 2004. Since it first appeared it has been observed informally and frequently. In January 2005 systematic observations were made of the marmoset and a capuchin of similar age. Throughout its period of adoption the marmoset appeared to be socially integrated into the group, benefiting from nurturant behaviors exhibited by two successive adoptive "mothers" and pronounced tolerance from all members of the group. This case highlights the flexibility of both Callithrix and Cebus in accommodating variable social behaviors and other characteristics (including size) of social partners.     

Intimate social behavior in infant interactions in Cebus apella

The development and individual stability of three intimate social behaviors (Lipsmacking, Carrying Attempts, and Facial Inspection) were examined for 43 group-housed Cebus apella infants from birth to 2 years of age. Occurrence of these behaviors was scored from 10-min videotape samples recorded three times a week over that time. Frequency of Lipsmacking and Carrying Attempts by adult males, adult females, and juveniles were all highest in early months and decreased to low levels by the end of the first year. Facial Inspection of partners by infants, in contrast, first began at 3-4 months and increased over time, at least to adult males and juveniles. Correlational analyses indicated stable individual differences in these interactions with infants and outlined a relationship between these intimate behaviors and more general social patterns reported previously for these animals. Results suggest that adult males may play a special role in affording juveniles opportunities for social learning of foraging and manipulative skills.