By Will Dunham
Current theory about the shape of the human face just got a big punch in the mouth.
Two University of Utah researchers proposed on Monday that the face of the ancestors of modern humans evolved millions of years ago in a way that would limit injuries from punches during fist fights between males.
Their theory, published in the journal Biological Reviews, is presented as an alternative to a long-standing notion that changes in the shape of the face were driven more by diet – the need for a jaw that could chew hard-to-crush foods such as nuts.
“Studies of injuries resulting from fights show that when modern humans fight, the face is the primary target,” biologist David Carrier said. “The bones of the face that suffer the highest rates of fracture from fights are the bones that show the greatest increase in robusticity during the evolution of early bipedal apes, the australopiths.”
These are also the bones that show the greatest difference between women and men in early human ancestors and modern humans, Carrier added.
In both apes and humans, males are much more violent than females, and most male violence is directed at other males, Carrier said. The violence underpinning the need for a more robust facial structure may have involved fist fights over females, resources and other disputes.