Theories of the evolution of upright locomotion in primates (bipedal walking and suspensory arm-swinging) generally assume a starting point of adaptation to arboreal quadrupedalism. All these theories have assumed that quadrupedal locomotion in a complex, discontinuous arboreal habitat requires a unique pattern of flexible forelimb use accompanied by reduced weight support by the forelimb, and that together these factors allowed for the development of several specialized hominoid locomotor behaviors. However, no study exists to date that evaluates the differences in forelimb use between arboreal and terrestrial primate quadrupeds travelling in both sorts of environments. And no study in this area has examined the actual mechanics of forelimb use in these quadrupeds. This study, from the finest laboratory investigating the kinetics and kinematics primate locomotion, will provide such an analysis of a variety of primate species with different locomotor patterns. Preliminary studies already suggest very different sorts of forelimb use of a single species when involved in different sorts of locomotion. The results of this study will provide empirical data with which we may better understand primate quadrupedalism and be able to evaluate the accepted stereotype of arboreal quadrupedalism as a basis for erect locomotion. This project is also important in its contribution to the training of a promising young scholar in biological anthropology.
