That is some overt bipedalism there :) Many (most?) monkeys like chimpanzees have opposable thumbs on their “feet” so they’re more like a second pair of hands,

That is some overt bipedalism there :) Many (most?) monkeys like chimpanzees have opposable thumbs on their “feet” so they’re more like a second pair of hands, which get exercised as such by gripping tree branches. Humans, on the other hand, keep their bottom hands in rigid clothing so they never get any real exercise.