Food-washing among wedge-capped capuchin monkeys (cebus olivaceus)

2001 ◽  
Vol 16 (3-4) ◽  
pp. 225-228 ◽  
Author(s):  
B. Urbani
Keyword(s):  
Capuchin Monkeys ◽  
Cebus Olivaceus ◽  
Food Washing

Demography and Group Structure in Wedgecapped Capuchin Monkeys, Cebus Olivaceus

Behaviour ◽  
1988 ◽  
Vol 104 (3-4) ◽  
pp. 202-232 ◽  
Author(s):  
John G. Robinson
Keyword(s):  
Sex Ratio ◽  
Life Table ◽  
Group Structure ◽  
Age Distribution ◽  
Capuchin Monkeys ◽  
Demographic Parameters ◽  
Adult Size ◽  
Sex Composition ◽  
Cebus Olivaceus ◽  
Age And Sex

AbstractThe extent to which population demography determines the age and sex composition of primate groups was examined using data from a population of wedge-capped capuchin monkeys Cebus olivaceus in central Venezuela. Demographic parameters were derived from censuses of individually recognized, aged, and sexed individuals living in nine groups over a ten year period. Animals were aged by extrapolation from census data. Animals of both sexes were classed as infants during their first year, and juveniles until they reached six years of age. Females reach sexual maturity at this time, while males were classed as subadults until they reached full adult size at age 12. Adulthood lasts at least 30 years in females, at least 24 years in males. Age-sex class specific mortality and fecundity rates generated a life table which indicated that the population was increasing (r = 0.087) between 1977 and 1986. The age and sex composition of the nine groups was described annually. On average, non-adults made up 60% of a group, with this percentage increasing with group size. There were more females than males in all groups in all years. The strong female-biased adult sex ratio (1:4.4) was a consequence of a biased birth sex ratio (1:1.9), higher female than male survivorship especially between the ages of 3 and 7 when males were dispersing, and a pronounced sexual bimaturism. The stable age distribution derived from the life table successfully predicted the observed average distribution of age-sex categories in groups. This suggests that the group structure of Cebus olivaceus groups is not a consequence of intragroup social interactions, but results from demographic parameters.

The Influence of Group Size On Predator Scanning and Foraging Behaviour of Wedgecapped Capuchin Monkeys (Cebus Olivaceus)

Behaviour ◽  
1986 ◽  
Vol 98 (1-4) ◽  
pp. 240-258 ◽  
Author(s):  
Jan R. De Ruiter
Keyword(s):  
Group Size ◽  
Foraging Behaviour ◽  
Group Formation ◽  
Food Competition ◽  
Food Sources ◽  
Capuchin Monkeys ◽  
Time Budgets ◽  
Large Group ◽  
Cebus Olivaceus ◽  
Travel Distances

AbstractThe behaviour of two groups of wedgecapped capuchin monkeys, Cebus olivaceus, a small one (n = 8) and a large one (n = 25) was recorded. Time budgets and other aspects of behaviour depended on group size. The differences can be explained as: adjustment to predation risk and intra-group food competition. In order to evade predation, members of the small groups scan more and stay at greater heights than those of the large group. Higher food competition within the large group was reflected in the composition of its diet, in longer travel distances, and higher levels of social behaviour. In particular during the dry season, the large group exploited unattractive and risky food sources. These results support ALEXANDER'S hypothesis on the causes of group formation.

Patterns of individual diet choice and efficiency of foraging in wedge-capped capuchin monkeys (Cebus olivaceus).

1995 ◽  
Vol 109 (4) ◽  
pp. 339-348 ◽  
Author(s):  
Dorothy M. Fragaszy ◽  
Sue Boinski
Keyword(s):  
Capuchin Monkeys ◽  
Diet Choice ◽  
Cebus Olivaceus

Spontaneous Use of Tools by Wedge-Capped Capuchin Monkeys (Cebus olivaceus)

1999 ◽  
Vol 70 (3) ◽  
pp. 172-174 ◽  
Author(s):  
Bernardo Urbani
Keyword(s):  
Capuchin Monkeys ◽  
Cebus Olivaceus

Syntactic Structures in the Vocalizations of Wedge-Capped Capuchin Monkeys, Cebus Olivaceus

Behaviour ◽  
1984 ◽  
Vol 90 (1-3) ◽  
pp. 46-78 ◽  
Author(s):  
John G. Robinson
Keyword(s):  
Discriminant Analysis ◽  
Animal Communication ◽  
Internal State ◽  
Time Spectrum ◽  
Total Sample ◽  
Capuchin Monkeys ◽  
Cebus Olivaceus ◽  
Internal States ◽  
Call Classification

AbstractCapuchin monkeys, Cebus olivaceus, combine different types of calls to form compound calls. These compound calls are syntactically organized (i. e. , there is a predictable ordering of call types in the compound call). The analysis of the syntax of animal communication necessarily includes: (a) Accurate classification of types of calls, and a demonstration that calls that occur both alone and in compound calls are structurally similar. (b) Description of the syntactic rules generating compound calls or call sequences, and classification of types of compound calls or call sequences. (c) Examination of the social circumstances or contexts in which both single and compound calls occur. I followed these steps using a large sample of Cebus olivaceus calls, recorded in riparian gallery forest in central Venezuela. The calls were initially screened using a real-time spectrum analyzer, and a group of structurally related call types was selected for further analysis. Temporal and frequency characteristics of 868 of these calls were measured from sound spectrograms produced on a sound sonograph. Call classification involved first defining a very large number of possible call types on the basis of these characteristics, and then using a discriminant analysis to identify which types should be lumped together. A stepwise procedure was followed, using only calls which occurred singly, until five call types (squaws, chirps, trills, whistles, screams) were statistically separable. Two of these types (trills, whistles) showed considerable within-type variation and were further subdivided into four variants each. Discriminant analysis was then used to demonstrate structurally similarity between calls produced singly and those in compound calls. Social circumstances were defined using similarities in the vocalizer's actions, arousal, orientation to and distance from the presumed receiver. Use of call types, when given singly, covaried predictably with social circumstances and presumably with the internal state of the vocalizer. Different calls expressed different internal states on a continuum from contact-seeking to contact-avoiding. Use of trill and whitle variants also covaried with social circumstances. Different variants expressed different states on a continuum from affiliation or submission to aggression. Combinations of internal states, in theory, might be expressed as intergradations or intermediates between different call types. However, such intermediate states are often coded syntactically. Syntactically organized compound calls accounted for 38% of the total sample. The distribution of social circumstances in which compound calls are given was intermediate between the distributions of the constituent call types, which presumably indicates an intermediate internal state. Compound calls are generated by syntactic rules closely analogous to lexical rules of human language. Specifically they act like compounding rules that combine two lexical entries to form a third. They are not analogous to the grammatical rules that generate human sentences.

Infanticide in Wedge-Capped Capuchin Monkeys, Cebus olivaceus

1990 ◽  
Vol 54 (3-4) ◽  
pp. 171-176 ◽  
Author(s):  
Ximena Valderrama ◽  
Sompoad Srikosamatara ◽  
John G. Robinson
Keyword(s):  
Capuchin Monkeys ◽  
Cebus Olivaceus
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