The primary objective of this research is to establish the relationship between finger and toe bone structure and the amount of time monkey species spend on the ground and in the trees. Researchers have predicted that stress on the finger and toe bones of animals living on the ground ought to be greater than those spending most of their time in the trees. To test whether this prediction is correct, the investigator will calculate the strength of toe and finger bone shafts using structural engineering equations. The values used in the equations will be obtained from measurements of radiographs of hand and foot bones of ten monkey species. Captive and free-ranging individuals of each of the monkey species will be filmed walking and running. The films will be used to determine the hand and foot postures each species commonly uses when walking on the ground and branches. It is thought that the human lineage evolved from arboreal ancestors and, over several million years, evolved to spend more and more time on ground. Results from this study may help in reconstructing the degree of arboreality characteristic of early hominoids.
