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Group fusions and minimum group sizes in vervet monkeys (Cercopithecus aethiops)
Lynne A Isbell1, Dorothy L Cheney2, Robert M Seyfarth3
1Animal Behavior Group, Department of Anthropology, University of California, Davis.
American Journal of Primatology
|January 19, 2020
Summary
Adult vervet monkeys (Cercopithecus aethiops) are crucial for maintaining group cohesion. Group fusions in Amboseli National Park were triggered by the loss of adults, not juveniles, suggesting competition influences group dynamics.
Area of Science:
- Primatology
- Behavioral Ecology
- Conservation Biology
Background:
- Vervet monkey (Cercopithecus aethiops) populations in Amboseli National Park, Kenya, have experienced declines.
- Understanding the social dynamics and factors influencing group stability is crucial for this species.
Purpose of the Study:
- To investigate the causes and timing of group fusions in vervet monkeys.
- To determine the role of adults versus juveniles in maintaining group cohesion.
Main Methods:
- Observation of six cases of group fusion in vervet monkeys between 1984 and 1988.
- Analysis of the relationship between group composition (adults vs. juveniles) and the timing of fusion events.
Main Results:
- Group fusions occurred after the loss of the penultimate adult, regardless of the number of juveniles present.
- Adults, both male and female, appear essential for maintaining group cohesion.
- Juveniles did not influence the timing of group fusions.
Conclusions:
- The loss of adult vervet monkeys is a primary trigger for group fusions.
- Intergroup competition may be a more significant factor than predation avoidance in driving group fusions.
- Adults play a critical role in the social stability of vervet monkey groups.
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