Through the Looking Glass: Effects of Visitors on Primates in Zoos

Daily exposure to visitors as well as caretakers makes the zoo environment a unique setting for primates in human care. Understanding how visitors impact zoo-housed primates is key to continually improving their welfare. Herein, we review decades of research on visitor effects in primates, many of which report a combination of effects. The majority of studies suggest visitors are a negative or neutral stimulus, although nearly a third also report some positive effects. Limitations in existing research impede our ability to fully understand how primates perceive visitors. Furthermore, a reliance on negative indicators of welfare and the continued assumption of negative impacts due to early research is likely to bias how results are interpreted. We discuss a need to critically reevaluate our assumption that visitors are inherently negative, especially in modern zoos which have larger, more spacious habitats that allow animals to express greater choice and control and provide potential mitigation strategies if some visitor stimuli are found aversive.