Positive and Negative Interactions with Humans Concurrently Affect Vervet Monkey (Chlorocebus pygerythrus) Ranging Behavior

Many nonhuman primates adjust their behavior and thrive in human-altered habitats, including towns and cities. Studying anthropogenic influences from an animal's perspective can increase our understanding of their behavioral flexibility, presenting important information for human-wildlife cohabitation management plans. Currently, research on anthropogenically disturbed wildlife considers either positive or negative aspects of human-wildlife encounters independently, highlighting a need to consider potential interactions between both aspects. Vervet monkeys (Chlorocebus pygerythrus) are a suitable species to address this gap in research as they tolerate urbanization; however, they are understudied in urban landscapes. We conducted this study in KwaZulu-Natal, South Africa, where vervet monkeys are commonly found throughout the anthropogenic landscape. Here we determined, from a monkey's perspective, how the frequency and nature of human-monkey interactions, both positive (human food availability) and negative (human-monkey aggression), affected vervet monkey ranging patterns in an urban environment. We assessed the movement patterns of three groups of urban vervet monkeys over 1 year, analyzing both 95% and 50% kernel density estimates of their home ranges alongside daily path lengths and path sinuosities every month using generalized linear mixed models. Overall, we found that human interactions within the urban landscape affected all measures of ranging to some degree. The core home ranges of vervet monkeys increased with a higher rate of positive human encounters, and their total home range increased with an interaction of both positive and negative human encounters. Furthermore, vervet monkeys were less likely to respond (i.e., increase daily path length or path sinuosity) to human aggression when food rewards were high, suggesting that effective management should focus on reducing human food foraging opportunities. Our results highlight the complex interplay between positive and negative aspects of urban living and provide guidance for managers of human-nonhuman primate interactions.