Getty Images

A strong jawline is generally considered one of a man's most attractive facial features*, and it serves a purpose beyond just looking good. "Robust" male facial features evolved to withstand punches during fistfights, according to a new paper published today in the journal Biological Reviews.

The bones that are most susceptible to impact during a fight are the same bones that became the strongest during early phases of evolution. These are also the bones that differ most in female faces.

Advertisement

"In other words, male and female faces are different because the parts of the skull that break in fights are bigger in males,” said Professor David Carrier, an evolutionary biologist at the University of Utah and lead author of the paper.

The "protective buttressing" theory goes against the long-held view that robust facial features evolved so that humans could chew tough foods, like seeds and nuts. In fact, Carrier says, our "nut cracker" ancestors were probably eating fruit instead.

Reconstruction of 'boisei', the “Nut Cracker Man,” by Cicero Moraes

"This reconstruction of boisei, the 'Nut Cracker Man,' does a very good job of illustrating the facial features we are discussing," Carrier told Fusion.

Advertisement

The strong brow, cheekbones and jaw all functioned to withstand punches during frequent hand-to-hand fighting, the research suggests. Further evidence that male faces were built to be punched relates to the evolution of our fists.

“Importantly, these facial features appear in the fossil record at approximately the same time that our ancestors evolved hand proportions that allow the formation of a fist," Carrier said.

So while humans evolved to throw punches, facial features simultaneously evolved to withstand them.

Photographs of skull reconstructions comparing chimpanzees with four hominins, courtesy David Carrier

The "protective buttressing" theory brings up questions about whether our distant past was, by nature, violent or peaceful. Carrier expects the paper to spark up the debate surrounding violence and human evolution.

“Our research is about peace," said Dr. Michael Morgan, co-author of the study. "We seek to explore, understand, and confront humankind's violent and aggressive tendencies."

*according to one of the creepiest videos on the internet and common knowledge.

Alexandra DiPalma is a producer for Fusion Lightworks, Fusion’s In-house Branded Content Agency.