The human face may have evolved over time because of violence, new research suggests. Researchers from the University of Utah Health Sciences found that human faces likely evolved to minimize injury from punches.

According to researchers, specific forms of violence included prehistoric versions of bar fights, with possible motivations for violence  ranging from women to resources, according to  the journal Biological Reviews on June 9.

David Carrier, University of Utah biologist, and Michael H. Morgan,  University of Utah physician, believe human faces, particularly of our australopith ancestors, evolved to help minimize injuries from facial punches in fights between males.

The findings, outlined in the paper “Protective buttressing of the hominin face,” provide an alternative to the previously held belief that the human face evolved primarily according to  the demand food foods that are difficult to crush, such as nuts.

According to Carrier, the study’s lead author, “The australopiths were characterized by a suite of traits that may have improved fighting ability, including hand proportions that allow formation of a fist; effectively turning the delicate musculoskeletal system of the hand into a club effective for striking.” He continued, “If indeed the evolution of our hand proportions were associated with selection for fighting behavior you might expect the primary target, the face, to have undergone evolution to better protect it from injury when punched.”

According to the Centers for Disease Control and Prevention, the number of emergency department visits for assault is approximately two million per year.