The Rise and Fall of Climbing in Human Evolution

Most primates live and move in the trees, but humans have evolved to move bipedally on the ground. Primates’ arboreal life-style has long been thought to have allowed the evolution of human beings’ unusual form of movement. We know much about how horizontal movement on branches (or simulated branches) differs in primates relative to most other mammals. But only recently have we begun to learn about how vertical movement (i.e. climbing) is accomplished by non-human primates, and how such movement may have permitted early human ancestors to move upright. However, climbing is a physically challenging activity, and not all primates (including humans) do it the same way. Body size plays a role in how muscles are able to accomplish overcoming gravity. But muscles consume energy to do this. What are the biomechanical and energetics costs of climbing? Key findings regarding the biomechanics of climbing, and what these data may mean for understanding human movement and exercise, are discussed.