Human Hands Evolved to … Punch?

If you've seen Stanley Kubrick's 1968 sci-fi masterpiece "2001: A Space Odyssey," then the idea of humanity's violent evolutionary ascension isn't news. In the film's iconic "Dawn of Man" segment, early hominids discover the power of tool use — specifically the you-go-smash-now technology of braining a tapir with a chunk of bone.

As we cover in the video, University of Utah biologist David Carrier's theory paints an equally blood-soaked picture of human evolution, only violence enters the picture much sooner.

Carrier posits that our tool-using hands evolved to punch each other in the face. In its current form, the closed fist protects the hand's delicate bones, muscles and ligaments during impact. So, the biologist says, there could have been a mating and survival advantage for the males who could out-punch the competition and still use their fingers. Furthermore, he also suggests that our prehuman ancestors evolved the sort of broad-jawed, stub-nosed faces that could endure the punishment.

This latest study, published in the Journal of Experimental Biology, tests the theory out by flaying some human cadaver arms, stringing the tendons up with puppet string and launching them via pendulum into a padded, force-detecting dumbbell.

Carrier and his team found that a clinched fist did provide significant protection for the puncher's metacarpal bones. Specifically, a clinched fist can safely strike with 55 percent more force than an unclenched one — and 200 percent more force than an open-hand slap.

Sadly, we'll have to keep waiting for a study on prehistoric super kicks.