One of the primary purposes of this study is to assess physiological stress responses of free-ranging Sykes monkeys (Cercopithecus mitis) under different degrees of human influence at two different sites in Kenya. Frequent human-animal interactions range from indirect provisioning by making various crops available for monkeys to raid seasonally (maize, beans, various fruits) to direct feeding of monkeys by visitors with small amounts of energy-rich foods (bananas, mangos, sweets). Similar conditions are typical worldwide in places where humans encroach the habitat of non-human primates, including in protected areas where tourists come in close contact with wildlife. The clumped distribution of high quality food resources have previously been shown to lead to increased levels of competition between animals, which in turn is known to increase social stress. Chronic stress has been related to serious health problems in primates and other mammals, and therefore presents a feasible way of assessing the long-term consequences of human-wildlife interactions for the viability of populations in a human dominated landscape. At each site, the study includes one social group with little or not contact to humans, so that the magnitude of effects of human activities relative to more natural conditions can be assessed.

This research will enable us to assess and help predict impacts of human - wildlife interactions on the health and survival of non-human primates. Although the species under investigation is itself not classified as endangered, Sykes monkeys can serve as an ideal model for how similar, endangered species will respond physiologically and behaviorally to human encroachment of their habitat. About half of guenon species are currently considered endangered to some degree, and many will face a significant reduction of their forest habitats in the near future. The populations that survive in protected areas, forest islands, or community managed forests will face increasing contact to humans, followed by alterations of their habitats and food sources, the effects of which are currently largely unknown. It is vital for conservation biologists to know how surviving wildlife populations will cope with these less dramatic environmental changes brought about by human activities or simply human presence in and around their home ranges.