As a proud beard-wearer throughout my adult life, I’m not about to test a new theory that early male humans evolved the ability to grow full, bushy beards in order to protect their jaws from at least some of the force of a punch. Do you have time to grow one before your next family reunion? How did they test this? Let’s find out.
“As is the case in other species of great apes, human males perpetrate the vast majority of violence and most of these acts of aggression are directed at other. When human males fight hand-to-hand, the face is usually the primary target. Consequently, it is not surprising that human males suffer substantially more injuries to the face from interpersonal violence than do females. Epidemiology studies of interpersonal violence indicate that males suffer 68–92% more injuries to the face from fights than do females.”
That’s the first punch delivered by University of Utah researchers E A Beseris, S E Naleway and D R Carrier in their paper, “Impact Protection Potential of Mammalian Hair: Testing the Pugilism Hypothesis for the Evolution of Human Facial Hair,” published in the journal Interactive Organismal Biology. They point out that this tendency to rearrange faces has resulted in male facial bones evolving much differently than females. It’s long been assumed that facial hair was strictly a sexual device to show masculinity, social dominance and strength to females who already have other, different ways to attract males. However, the beard covers the mandible — one of the most commonly fractured facial bones in fights and one that brought grave consequences before the advent of modern surgery. Could a bushy beard block blows to the mandible? If only those Duck Dynasty guys were boxers.
“Human bone tissue was modeled using a short fiber epoxy composite bone analog (manufactured by Pacific Research Laboratories, Inc., Vashon, WA), which has material properties similar to human cortical. Because it was not practical to obtain fully bearded skin samples from human cadavers, and loose human hair was anticipated to not distribute the force of impact the way in situ hair may, we used skin samples from domestic sheep (Ovis aries) purchased from a local slaughterhouse.”
The researchers used sheep fleece to simulate full beards because they have approximately the same volume. They shaved some to mimic a smooth face. What about the punches? An angry ram with a horn fitted with a fist?
“This test involves dropping a blunt striker (diameter ∼3 cm, mass = 4.70 kg), from a known height toward a material sample mounted on an anvil. The anvil had a 55 mm × 50 mm hole to allow free suspension of the sample and to avoid effects of the contact between the anvil and sample that could alter the results.”
An anvil jaw – think actor Jon Hamm or football’s Tom Brady (there’s a lot of people who would like to take a swing at Brady’s jaw). The force of the striker was set to match the force of the average punch. So, how did the bearded (furred) anvil chins take a blow?
“Our results show that on average the furred samples absorbed nearly 30% more energy than the sheared and plucked samples.”
Thirty-percent absorption just might be enough to give a bearded cave man the edge he needed to protect his cave and his woman. The beards may have also reduced cuts and bruises, so it seems like a pretty solid argument in favor of hairy male mandibles, especially for early humans who could grow bushy beards like modern Middle Eastern and Northern European men, not like clean-faced East Asian and American Indian males.
While this is an obvious advantage for prehistoric males, what about today’s boxers and mixed martial artists? Boxing has long accepted this, which is one reason why beards are banned – the other is that hairs could get into a cut and infect it. Many MMA fighters have beards, but that’s more of a sign of lax regulations than a preference. And there’s no indication that beard-pulling is used as a tactic.
So, if you’re worried about getting into fisticuffs at your next family reunion … stay home. You’ve got bigger problems that facial hair won’t help. And your grandma probably wouldn’t like the way you look anyway.