The main goal of this project is to compare Sanje mangabey fecal parasite prevalence, species richness and diversity to levels of human disturbance in the Udzungwa Scarp Forest Reserve (USFR; see attached map). These data will be used to evaluate the effects of human activities within the USFR on the gastrointestinal health of the Sanje mangabey. Our team sampled an area of the USFR close to a highly populated village, Ikule, and a more isolated area within one-day walking distance to the village of Chita (see attached map). Data collection is ongoing; however, preliminary analysis of human encounter rates suggests that the Sanje mangabey population near Ikule is more heavily exposed to human activity compared to that of the Chita population. For example, during the second trip to Ikule, no mangabey groups were encountered. We suspect that the heavy presence of humans in the forest over those four days of transects may have influenced the ranging patterns of the Sanje mangabey groups in the area. In addition, the Endangered Iringa red colobus (Procolobus gordonorum), was neither seen nor heard on either trip (see Table 1) to the forest neighboring Ikule. Villagers in this area were observed harvesting firewood and the sounds of gunshots suggests hunting activity. In contrast, during two 4-day trips to Chita, our team encountered groups of both the Sanje mangabey and Iringa red colobus. Our team will complete one additional trip to Ikule (Mar. 2011) and Chita (Apr. 2011). Though data collection is ongoing at this time, preliminary observations support our initial claim that the mangabeys in the USFR are severely threatened by habitat destruction and human activities in the area. Villages surrounding the USFR have experienced a continuous increase in population size during the last decade. This increase has certainly intensified human pressure and disturbance in multiple areas within the reserve. Given the observable differences in human and monkey encounter rates between the Ikule and Chita transects, it is necessary to conduct a large-scale, systematic survey of the USFR to acquire an updated estimate on human disturbance, gastrointestinal health and population size of the Sanje mangabey and other endangered primates. The numbers currently available for these parameters were collected more than a decade ago and represent only a portion of the USFR. As such, results from these six trips will help us to determine how best to design and implement a large-scale survey of the area to gather more complete and up-to-date information on the impact of human disturbance on the Sanje mangabey and sympatric primate species.