Humans are very efficient walkers, and a key component of being an efficient walker in all kind of mammals is having long legs,” Webber said. “Cats and dogs are up on the balls of their feet, with their heel elevated up in the air, so they’ve adapted to have a longer leg, but humans have done something different. We’ve dropped our heels down on the ground, which physically makes our legs shorter than they could be if were up on our toes, and this was a conundrum to us (scientists).
Turns out heel-to-toe rolling gives longer *effective* leg length. Our lower legs are exquisite.