What accounts for the skeletal differences between chimpanzees and humans?

Answer 1

Starting from the top, the skulls of Chimps have a smaller brain pan and much larger jaws. Their rib cage is bell shaped to accommodate their high fiber diet; they eat lots of plants, fruit, nuts, and seeds. Their shoulders are positioned on the back as opposed to the sides. Their arms and hands are much longer, and their hands do not bend backwards at the wrist like ours do because that would inhibit the strength needed for swinging through the forest. Plus, this would lessen their ability to walk on their hands. Their necks, spines, and pelvises provide them with their characteristic bent at the waist, head forward posture, which compliments their partial arboreal lifestyle. Their legs are much shorter in comparison with their arms. And lastly, their feet are much different than ours, very hand-like. These are of course used for climbing trees and grasping branches.