Zoo visitors as a source of enrichment to reduce abnormal behavior in captive rhesus macaques (Macaca mulatta) in the Central Zoo, Kathmandu, Nepal

Overexpression of abnormal behavior among captive primates indicates poor management practices. The type, frequency, and contributing factors of abnormal behaviors vary highly across individual animals in captive settings. This study explored if sex, rearing history, the number of visitors, and type of visitor-monkey interactions affected the behaviors of captive rhesus macaques (Macaca mulatta) housed at the Central Zoo in Kathmandu, Nepal. Behavioral observations of six adult rhesus macaques (ages 4-12 years; two were rescued from the wild, and four were born in the zoo) were conducted using the focal animal sampling method. Observations were collected daily in two conditions (7:00-10:00 AM, without visitors present; and 10:00 AM-1:00 PM, with visitors present). During the visitor presence condition, instantaneous scan sampling also was implemented every 10 minutes to record the number of visitors and the type of visitor-monkey interaction. Resting, feeding and grooming were the most prevalent activities, and abnormal behavior ranked fifth throughout the observation period. Significant differences were observed in abnormal or stress-related behavior by sex and rearing history: females engaged in abnormal behavior more than the males, and rescued monkeys engaged in more abnormal behavior than the captive born. Abnormal behavior decreased, begging behavior increased as the number of zoo visitors and the extent of visitor-monkey interaction increased. We conclude that captive rhesus macaques respond to zoo visitors as a source of enrichment, and visitors' presence helps decrease abnormal or stress-related behavior levels.