you characterized human walking as controlled falling--does animal walking take more effort because they have 4 legs, they have to push off each one? what about the relative stresses of human vs animal running? is there an example of a well-muscled animal that doesnt have such trouble with fragility, or a social animal that can care for wounded members of its group? we've sort of gotten away from anthropology huh lmao Sorry! I guess... what pressures selected for the above in humans?