This research project will focus on the distribution, habitat selection and behavior of two lemur species, Lemur coronatus and Lemur fulvus sanfordi, in northern Madagascar. The investigators will attempt to determine whether significant differences exist in the resource use of these two morphologically similar, yet co-occurring, primate species. The proposed research situation is unique. It represents one of the few opportunities available to test theories of competition between primate species. The information gathered in this project will help answer questions concerning the interrelationships between ecology, morphology, social behavior and evolution in primates.