Humans routinely assess other people by relying on information gained during previous experiences with a particular individual (?individual recognition?). Indeed, individual recognition is the primary means of assessment for most primate species. However, a growing body of evidence indicates that humans also use physical characteristics (?quality signals?) as a way to evaluate others ? particularly in the context of competition and mating. One reason why humans might utilize quality signals is because they live in extremely large social groups where they frequently encounter individuals they do not recognize. However, this hypothesis is difficult to test because quality signals are rare among primates, and little is known about the function and use of signaling in non-human primates. Thus, the main objective of this research is to determine how primates living in large groups ?size up? potential rivals and mates ? a task that involves mapping the boundary of where individual recognition ends and where other short-hand means of assessment begin. The subjects for this research are wild geladas (Theropithecus gelada), a monkey that lives only in the highlands of Ethiopia. Geladas are an ideal species for this research for two reasons. First, while the vast majority of primates live in small groups where individuals recognize every group member, geladas (like humans) live in extremely large groups where individual recognition may not extend beyond a small subgroup. Second, male geladas are unusual among primates in having 2 conspicuous traits that may serve as quality signals, a red patch of skin on the chest and neck, and ritualized display vocalizations. By combining behavioral observations, experimental playbacks, and laboratory analysis of fecal steroid hormones, this research addresses 3 questions: (1) What are the limits of individual recognition in gelada society? (2) For recognized individuals, do they base reproductive decisions on this information? (3) Alternatively (or additionally), do geladas use quality signals, such as chest color or vocal displays, to evaluate potential competitors or mates?
The PI and co-PI of this project are committed to integrating research goals with education and conservation at several levels. First, over the course of this three-year project, a post-doc will receive training in playback experiments and hormone analysis, 4-6 graduate students will gain summer field experience, and 6-8 undergraduates will gain experience analyzing data for senior theses. Second, it is expected that 1-3 Ethiopian graduate students in primate behavior will join the project. Third, an Ethiopian counterpart will be sponsored for graduate training in wildlife management. Finally, this project's research presence in the Simien Mountains National Park (currently on the list of World Heritage Sites in Danger) is assisting conservation efforts. Conservation projects that have been initiated thus far include: a census of geladas living in the area, a survey for tourists on park conservation, and a survey for the local people to gauge the degree of human-wildlife conflict. Both the PI and co-PI will continue to dedicate a fraction of their field time to conservation efforts in the area.
