NASA's Robert O. Ambrose has co-authored a new research paper titled Primate Anatomy, Kinematics, and Principles for Humanoid Design (PDF format). The paper investiages the theory that kinematics, musculature, perception, and cognition can be optimized for specific tasks by varying the proportions of limbs. Known as the Bifurcated Chain Hypothesis, the idea is that the proportions of humans made them superior to other primates and animals at specific tasks such as tool-making. Ambrose has studied body articulation and its application to robotics for some time. You may also recognize his name from the NASA Robonaut project.