Chimpanzee feet are quite different from human feet and there is much to be gleaned from the difference. Conventional wisdom has always claimed that the human mid-foot is rigid, which allows more efficient walking while chimpanzees and other apes have flexible feet better suited to grasping branches as they move through the trees.

The foot of non-human primates, such as chimpanzees, has an opposable hallux that faces the other four digits to allow the grasping of objects. By contrast, the hallux of the human foot is aligned in parallel with the other four digits; as such, the prehensile function is not afforded.