Behaviour 2019
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Within and between group agonism in male mantled howler monkeys living in a fragmented forest in Costa Rica
Lisa C Corewyn. Ithaca College, Ithaca, New York, United States

Understanding the nature and extent of a species’ behavioral flexibility is important as primates are increasingly impacted by anthropogenic change such as habitat fragmentation. Yet, we know little about how habitat fragmentation may affect primate sociality, particularly among males who are expected to remain competitive to structure access to females. I compared intergroup encounter (IE) and agonistic interaction (AI) rates among males in two large A. palliata groups within a fragmented habitat at La Pacifica, Costa Rica. I collected 1751 H of behavioral data on adult males from Jan-Dec 2010. Both groups were of similar size and sex ratio, but inhabited upland forest fragments of differing size, shape, and level of isolation. The group living in the smaller, irregular, more isolated fragment had fewer group neighbors, with lower IE (p=0.002), and higher AI rates (p=0.014) than the group inhabiting the larger, more intact, connected fragment. Results suggest that male A. palliata living in fragments may be under greater pressure to compete for resources compared to males living in more intact forests, but may adjust competitive relationships as fragment characteristics vary.