The impact of tourist visits on mountain gorilla behavior in Uganda

Tourism can play a significant role in the conservation of mountain gorillas (Gorilla beringei beringei) by financing the protection of their habitat, but few systematic studies have focused on the impacts of tourist presence on gorilla behavior. We assessed stress-coping mechanisms (Prosocial behaviors), behavioral indicators of stress (Self-scratching), and Human-directed behavior, in the presence and absence of tourist groups visiting one group of mountain gorillas living in Bwindi Impenetrable National Park, Uganda. Generalized linear mixed models were used to analyse differences in gorilla behavior as a function of (a) presence vs. absence of tourists and (b) proximity to tourists (3 m). Contrary to guidelines, tourists spent 60% of their viewing time within 3 m of the gorillas, and 96% of the tourist groups had more than 8 people. During tourist visits, gorillas increased time spent in Prosocial behavior and in rates of Self-scratching and Human-directed behavior. When tourists approached gorillas within 3 m, Prosocial and Human-directed behavior increased while Feeding decreased, but only adult males increased Self-scratching rates. We conclude that tourists are influencing gorilla behavior. We recommend following and enforcing the IUCN guidelines by keeping a minimum 7 m distance when viewing gorillas.