The over-reliance on living apes to study humans has stunted evolutionary theories, including how humans evolved bipedalism, the ability to walk on two hind feet.
With anatomy in perfectly aligned to bipedalism and lifestyles becoming increasingly static our muscles and airways may experience strain that good posture and movement can correct.
While many other primates are capable of bipedalism, you’ll see them moving around on all fours, known as quadrupedalism, a lot more than you will a human.
This suggests that upright posture could have been the starting point for bipedalism, instead of hanging ability—a theory that could not have emerged from studying living apes alone.