The Sanje mangabey (Cercocebus sanjei) is an endangered primate (IUCN 2011) endemic to the Udzungwa Mountains of south-central Tanzania, part of the Eastern Afromontane Biodiversity Hotspot (Mittermeier et al. 2004). Its current population, estimated at fewer than 1,500 individuals (Ehardt et al. 2005), is limited to two isolated forest blocks of the Udzungwa Mountains: Mwanihana Forest and the Udzungwa Scarp Forest Reserve (USFR). The population in the Udzungwa Scarp is threatened by illegal hunting, logging and agricultural encroachment, making it more likely that this population may disappear in the near future (Ehardt et al. 2005). Conversely, the Mwanihana Forest population is relatively well protected, as it is located within the Udzungwa Mountains National Park (UMNP). Nonetheless, there are rising tensions between neighboring villages and the national park. As of June 2011, villagers have been banned from entering the UMNP to collect firewood, which they had been allowed to do every Thursday for more than a decade. As a result, local perceptions towards UMNP vary significantly from that of the conservation community (Bancet 2007). In addition, conflicts between local farmers and villagers and the crop-raiding elephants and baboons have further widened this division (Joram 2011).

Despite first being described 30 years ago (Homewood and Rodgers 1981), studies on the Sanje mangabey have been limited; therefore, little is known about its behavior and demography (exceptions are Ehardt. et al. 2005, Ehardt and Butynski in press). At present, there are two habituated groups of Sanje mangabey, both within the Mwanihana Forest: the Mizimu group which is reserved for research; and the Njokomoni group which has been set aside for the sole purpose of promoting tourism. Initial research on the Mizimu group focused on ranging and feeding ecology (Ehardt et al. 2005). As of September 2008, research on the reproductive behavior and ecology of this group has been collected continuously as the Mizimu group has been monitored without interruption. This has allowed researcher to collect over three years of information on demography and life history parameters of the Sanje mangabey. Such information, previously unknown for this endangered primate, is essential for developing informed measures of population viability and sustainable conservation plans.

To continue monitoring the Mizimu group. In particular, research project will continue collecting data on the demography and life history parameters of the Sanje mangabey, to prevent disruption of our continuous data set which began September 2008.