The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)

Impact of anthropogenic factors on affiliative behaviors among wild bonnet macaques


1Population Health and Reproduction, University of California at Davis, 2Department of Human Evolutionary Biology, Adam Mickiewicz University, 3Department of Biomedical Science and Physiology, University of Wolverhampton, 4Department of Psychology, University of California at Davis, 5Centre for Research and Education in Ecology and Evolution, Indian Institute of Science Education and Research

April 16, 2020 8:30AM, Diamond 8-9 Add to calendar

In nonhuman primates, allogrooming confers many benefits, and may be influenced by many socioecological factors. Despite increasing conflict between humans and wild primates, the impact of anthropogenic factors on grooming remains understudied. We tested two contrasting hypotheses regarding how anthropogenic factors may influence macaques’ grooming and other affiliative interactions. We asked whether interactions with humans decreased macaques’ affiliative behaviors by imposing time-constraints, or increased affiliation on account of macaques’ consumption of anthropogenic foods culminating in more free-time. We collected data (11 months) on human-macaque and macaque-macaque interactions using focal-animal sampling on two groups of wild bonnet macaques (Macaca radiata)in Southern India. For each macaque, we calculated frequencies of human-macaque interactions, rates of foraging on natural/anthropogenic food, rates of monitoring humans, dominance ranks, grooming duration, grooming partner diversity, and frequencies of short-duration affiliative interactions (e.g., coalitionary-support, lip-smacking).We found strong evidence for time-constraints - macaques that monitored humans more groomed for shorter durations, and groomed fewer partners. These effects were independent of group ID, sex, dominance rank, and climatic season. However, monitoring humans had no impact on frequencies of short-duration affiliation. We found no evidence for the free-time hypothesis - foraging on anthropogenic food predicted neither grooming nor affiliation. Our results are consistent with recent findings on other macaque species/populations in human-impacted environments. Macaques in urban environments may rely more on short-duration affiliative behaviors for maintaining social bonds. More broadly, conservation research should evaluate inter-individual differences in primate/wildlife behavior.

This work was supported by the American National Science Foundation Coupled Natural and Human Systems grant (NSF-CNH #1518555) awarded to the PI Dr. Brenda McCowan.

Slides/Poster (pdf)