The faces of today's men would be different if our ancestors hadn't spent countless thousands of years slugging it out with their newly evolved fists, scientists say. Researchers studying australopiths, human predecessors who lived 4 million to 5 million years ago, found that male faces evolved to become stronger in areas most likely to be hit during a fist fight, including the jaw and structures in the eye, nose, and cheek areas, the Telegraph reports. The researchers earlier determined that australopiths were the first primates able to form their hands into fists—thereby becoming able to throw a punch.
The facial bones that grew stronger among the australopith males are still very different between men and women today. "In humans and in great apes in general ... it's males that are most likely to get into fights, and it's also males that are most likely to get injured," the lead researcher tells the BBC, noting that a broken jaw millions of years ago would probably have led to death by starvation. But since the time of the australopiths, the faces of their descendants, including humans, have displayed less and less of what the researchers call "protective buttressing." The researchers say that is probably the result of a decreased need for protection, as our "arms and upper body are not nearly as strong as they were in the australopiths." (Read more evolution stories.)