Men have evolved to grow beards in order to protect their jaws from incoming punches from foes, a study has found.
Facial hair is the most evident manifestation of s.e.xual dimorphism —
physical differences between males and females in humans.
But its actual purpose has long remained an enigma, with some
researchers claiming its purpose is to appeal to women and enhance their
University of Utah researchers set out to see if they could prove a beard was good at softening blows sustained in a melee.
They created analogues of the human jaw made from epoxy resin and
covered it in sheep skin covered in various levels of fur: hairless,
trimmed and a full-blown beard.
Skin was kept moist to simulate real skin while the fur, which imitates the beard, was kept dry during the experiments.
Researchers produced 20 of each type and then dropped a 10.3lbs (4.7 kg) metal weight onto the skin which was fixed to an anvil.
Writing in their study, the scientists say the experiment would be
improved if they could use actual human skin with facial hair still in
place, however admit it ‘was not practical’.
As the weight fell on the imitation human chin a machine detected how
much force went through the bone and how much was absorbed.
‘We found that fully furred samples were capable of absorbing more
energy than plucked and sheared samples,’ the researchers write in their
study published in the journal Integrative Organismal Biology.
‘For example, peak force was 16 per cent greater and total energy
absorbed was 37 per cent greater in the furred compared to the plucked
The energy of an impact, whether from a falling weight on an anvil or a
well-aimed uppercut, is spread out by the bushy facial hair
The scientists add: ‘The results of this study indicate that hair is
indeed capable of significantly reducing the force of impact from a
blunt strike and absorbing energy, thereby reducing the incidence of
‘If the same is true for human facial hair, then having a full beard may
help protect vulnerable regions of the facial skeleton from damaging
strikes, such as the jaw.
‘Presumably, full beards also reduce injury, laceration, and contusion, to the skin and muscle of the face.’
A study published earlier this year from the same team of researchers in
Utah also found further evidence that male bodies evolved with a focus
on hand-to-hand combat, and besting another man in a fistfight.
This study revealed that men throughout all of time have been forced to
scrap in order to win the affections of women and have children.
This pressure has caused male bodies to change, becoming more powerful and explosive when throwing a punch.
Over thousands of years, men unable to fight were slowly weeded out of
the gene pool and, as a result, modern males are accomplished at
The end result is that male bodies became specifically tailored by evolution to be good at punching.
For example, researchers in the US found that the weakest man punches harder than than the strongest woman in tests