Infant Mortality and Stress Indicators Linked to Tourism Management of Tibetan Macaques

Here we summarize research on the impact of tourism management on a population of wild Tibetan macaques. We compared long term data on infant mortality and adult aggression rates before, during and after a single group was used for tourism, and investigated short term effects of tourist presence and behavior on the behavior of the monkeys in the same social group and in an additional group. Long term results strongly suggest causal links between infant loss and management for tourism, and raise the hypothesis that artificial range restriction jeopardized infants by raising levels of aggression in the provisioning area. Infant mortality was significantly higher in the 11 years of tourist management than in the 6 preceding years, but was similar before and after management. Although few infanticides were witnessed, many infant corpses were found with wounds, and serious attacks on infants by adults were observed following outbreaks of aggression among adults in the provisioning area. Yearly rates of infant mortality were positively correlated with adult aggression rates in the provisioning area, and both factors were strongly associated with the degree to which the group’s range was artificially restricted. Analysis of immediate responses of monkeys suggested multiple ways in which tourist behavior may cause monkeys stress and aggression in the provisioning area. Threat rates increased when tourist noise levels were high and when tourists directed behavior towards the monkeys, especially when tourists pointed or slapped the rail. Increases in tourist density were associated with increases in self-directed behavior by the monkeys, a behavioral index of stress. Collectively these results suggest that tourism leads to high levels of stress, aggression and infant loss at this site. We offer several recommendations to minimize harmful effects and help ensure that natural behavioral patterns are fostered.