Rethinking Tolerance to Tourism: Behavioral Responses by Wild Crested Macaques (Macaca nigra) to Tourists

Abstract

There is an assumption that apparent tolerance of tourists at long-running primate tourism sites indicates habituation and that as a result primates no longer experience negative consequences of prolonged exposure to visitors. We examined effects of tourist presence on stress-related behavior in three groups of critically endangered, wild crested macaques (Macaca nigra) exposed to different intensities of tourism in Tangkoko Nature Reserve, Sulawesi, Indonesia. Group R2 has been exposed to research + intensive tourism for over 3 decades, R1 to research + less intensive tourism (1 decade), and PB1 to research only. Almost 740 h of data were collected from 33 adults via focal animal, all occurrence, and 1/0 sampling. All data were analyzed with general linear mixed models. Behavior appeared to be inhibited when tourists were in the forest, but not within groups; all groups vocalized less, exhibited fewer sexual behaviors and displayed fewer self-directed behaviors in months with greater numbers of tourists. When tourists were present vs. absent within groups, females displayed less affiliation, and males and females displayed more aggression, consistent with responses to uncertainty in the presence of tourists. Our results indicate that crested macaque groups exposed to tourism even for decades may not fully habituate to tourists. We tentatively suggest that their behavioral responses to tourists resemble typical responses of primates to perceived predators posing varying degrees of risk.