Abstract
Studies of primate locomotions have clarified the characteristics of human orthograde bipedal walking and have presented models of pre-habitual bipedal locomotion. Among nonhuman primates, chimpanzees have many characteristics of bipedal walking similar to those of humans. In order to investigate these similarities, development of chimpanzee bipedal locomotion was kinesiologically studied. The data were obtained semi-longitudinally from six chimpanzees of the age of two months through nineteen years. Voluntary bipedal walking of the infant chimpanzee until one year of age showed some patterns different from those of human walking. From two years of age, chimpanzees started to adopt a type of walking which economizes energy expenditure as in humans. From four years of age, their walking presented many similarities to those of humans, though there were many varieties of patterns in the chimpanzee bipedal locomotion among individuals and from step to step in an individual. The living chimpanzee after four years of age is useful for making models of the evolution of human bipedalism.
