Crested macaques are one of seven macaque species endemic to the Indonesian island of Sulawesi. They are also most endangered and have recently been included in the catalogue of “The World's 25 Most Endangered Primates”. Loss of natural habitat and illegal hunting are the main threats for the survival of this species and have led to massive population declines in recent decades. Comprehensive genetic analyses of the remaining, potentially isolated populations are vital to assess the impact of increasing anthropogenic pressures on their genetic structure as well as the species’ risk of inbreeding depression. The exceptional case of a macaque population that has been introduced to the nearby island Bacan, outside the native range, about 150 years ago may provide the opportunity to reintroduce animals to the mainland, thereby increasing variability of genetically depleted populations. The aim of my project is to collect non-invasive samples of crested macaques across the province of North Sulawesi as well as on Bacan Island. By genetically characterizing crested macaques across their range it will be possible to draw direct conclusions about the specific conservation needs of this species.