This article summarizes recent findings on the evolution and adaptation of primate locomotor behavior, and discusses the current status and future prospects of this field of study. Japan once led the world in this field of study, but currently the Japanese research community is not very active, partly because of the limited availability of facilities where experimental studies can be conducted. In addition, it has become more difficult to keep and breed primate species in the laboratory, especially in the last five years. By contrast, in the US and Europe, the numbers of researchers and papers in this field are increasing rapidly. This is partly because there are more facilities for experimental studies, but more importantly because they are developing various new approaches. These include sophisticated analyses of limb joint function using computer simulations based on computed tomography images and the statistical shape atlas. Collaboration with researchers in other fields of study, such as physiology, has also begun. In addition, some researchers have taken advanced kinematic apparatus to zoos to collect motion data, since zoos have many species and are now enriching the habitats of their animals. Although it is now more difficult to undertake experiments in the laboratory using living animals, there is still much that we can do. Locomotion is one of the most basic animal behaviors, and reflects both body structure and natural habitat. To discuss primate and human adaptation and evolution, information on locomotor behavior is essential. The various techniques introduced in the studies in this article will make the coming decades exciting and fruitful, and I really hope that this wave of activity spreads to Japan and reverses the recent decline of primate locomotion research.