Among many unique animals and plants on the island of Madagascar are more than forty species of lemuriform primates. In terms of skeletal anatomy these animals represent the best living analogues for the earliest euprimates (Eocene Adapidae and Omomyidae). Thus, a study of the positional behavior (posture and locomotion) of these animals is crucial for a thorough understanding of the locomotor system of early primates. Although aspects of social behavior and ecology of Malagasy lemurs have been the subject of several studies, positional behavior has not received the detailed, objective, quantitative scrutiny it needs in order to generate the kinds of data most useful for integration with morphological and historical studies. The purpose of this project is to collect such data for six species of Malagasy lemurs living among a community of 12 species at Ranomafana National Park. The number of species, ranges of body sizes, phylogenetic diversity, and microhabitats represented by these animals allow many crucial comparisons to be made which test the influence of various factors on the expressions of positional behavior. The results generated from this study will be compared with similar studies on other primates, with the aim of generating and testing the nature and regularity of the influence of body size, habitat structure, and heritage on primate positional behavior.