Behavioral diversity and agonism are higher in larger groups among wild Costa Rican capuchins.

This article investigates how group size influences behavioral diversity and agonistic interactions in wild white-faced capuchin monkeys (Cebus imitator) in Costa Rica, testing predictions of the Resource Distribution Hypothesis (RDH). Analyzing over 65,000 behavioral scans from 214 individuals across eight social groups over 15 years, the study found that larger groups exhibited higher behavioral richness and diversity both cross-sectionally at the group level and longitudinally within individuals. Additionally, larger groups showed increased frequencies of agonistic behaviors at the group level, indicating heightened competition, though individual-level agonism did not vary significantly with group size or dominance rank. These findings suggest that behavioral diversification may mitigate intragroup competition in larger groups, providing insights into social dynamics and potential constraints on group size in this primate species.