1Population Health & Reproduction, University of California Davis, 2Animal Behavior Graduate Group, University of California Davis, 3Anthropology, University of California Davis, 4California National Primate Research Center, University of California Davis, 5Anthropology, University of Notre Dame, 6, Gibraltar Ornithological and Natural History Society
April 14, 2016 , Atrium Ballroom A/B
The Barbary macaques of Gibraltar experience high levels of tourism. The steep terrain of the Upper Rock Nature Reserve allows individual macaques to choose whether to be near tourists or avoid them altogether (e.g. going down the cliffs). To examine how the anthropogenic environment may relate to social dynamics, we observed two groups of free-ranging Barbary macaques, Apes Den and Prince Phillips Arch. We examined whether individuals that chose to be near humans more often had different positions within their social networks. From activity scans (spanning the home range) we tallied the frequency each individual was present and the number of these scans with humans present. Grooming and aggression networks were constructed from focal sampling data across all adults. Poisson regression analyses showed that macaques that were more frequently near humans tended to be high ranking (b=0.017; p<0.001) and more peripheral in the grooming network (b=0.014; p<0.001) than those less often in the presence of humans. The rank effect may stem from high-ranking animals gaining priority access to food from tourists, though high-ranking individuals did not spend more time eating provisioned food than lower-ranking individuals. Further, the effect of groom network position may arise if individuals that are drawn toward humans have less inclination or time available to groom others. In fact, peripheral individuals in the groom network did spend less time grooming in their activity budgets (b=0.004, p<0.001). These results suggest that interaction with humans may impact macaque social dynamics in highly commensal groups of primates.