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Updated: Mar 31, 2026
08:04
Conditions Affecting Social Space in Drosophila melanogaster
Published on: November 5, 2015
13.1K
Optimal group size in a highly social mammal
A Catherine Markham1, Laurence R Gesquiere2, Susan C Alberts3
1Department of Anthropology, Stony Brook University, Stony Brook, NY 11794; Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544; markham.catherine@gmail.com altj@princeton.edu.
Summary
Intermediate baboon groups optimize space use and stress levels. Both smaller and larger groups face ranging challenges, contrary to previous assumptions about group size effects.
Area of Science:
- Behavioral Ecology
- Primatology
- Animal Social Systems
Background:
- Group size significantly impacts social animal behavior, influencing individual fitness and group cooperation.
- The ecological constraints model predicts how environmental factors shape group size and social dynamics.
Purpose of the Study:
- To investigate the relationship between group size, ranging patterns, and stress hormone levels in wild baboons.
- To test predictions derived from the ecological constraints model regarding group size effects.
Main Methods:
- Longitudinal study of five wild baboon groups over 11 years.
- Analysis of ranging patterns (home range area, daily travel distance, space use evenness).
- Measurement of adult female glucocorticoid (stress hormone) concentrations.
Main Results:
- A U-shaped relationship was observed between group size and home range area, daily travel distance, and evenness of space use.
- Glucocorticoid concentrations also exhibited a U-shaped pattern with group size.
- Intermediate-sized groups demonstrated energetically optimal space-use strategies.
Conclusions:
- Group size influences space-use efficiency and physiological stress in baboons.
- Within-group competition may constrain large groups, while between-group competition and predation pressure affect small groups.
- Findings offer hypotheses for group-size constraints in other social species.
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