Abstract: | The oceanic island of Simeulue, west of Sumatra, is inhabited by a distinct subspecies of the long-tailed macaque (Macaca fascicularis fusca) [Miller, 1903]. In January 1982 and March 1984, a survey was conducted to establish its population status. The monkey is morphologically different from other Sunda shelf M. fascicularis populations. In productive habitats, it lives in small groups (10–15 individuals) and reaches a density of more than one monkey/hectare (ha). The island's total population is estimated to be at least 50,000. The authors suggest that the location of a proposed reserve be shifted to include more of the most favorable habitat, i.e., alluvial forest. |