The term ‘knuckle dragger’ colloquially describes a person who exhibits a lack of intelligence. That expression is used to evoke the imagery of a gorilla or chimpanzee as a lesser evolved form (I take issue with that generalization, but more on that later). Still, it is accurate to observe that gorillas do walk on their knuckles. The question is why?

That’s a two-part question. Why does an ape walk on all fours as opposed to standing upright? The short answer is because their bodies have evolved that way. Take a look.

Skeletally and muscularly, gorillas are built to move quadrupedally. If you want to read more about the specific ways that gorillas and humans differ, there’s an excellent post that addresses this question on Anthropology.net here.

Fine, but why does a gorilla walk on it’s knuckles as opposed to it’s open hands? Again, it comes down to physical advantage…