Scientists have revealed the main function of a man's beard

Charles Darwin suggested that a man's beard could have appeared during sexual selection on approximately the same principle as a peacock's bright tail.: as an ornament that can attract the opposite sex. However, modern research shows that the story could have been much more interesting. A beard doesn't necessarily make a man more attractive to women, but it does make him look older, more statuesque, and more aggressive in the eyes of others. Why men need a beard and other details can be found in the Izvestia article.

The beard could not have appeared at all for the sake of women

In 2012, anthropologists Barnaby Dixon and Paul Vasey tested one of Darwin's ideas on men from New Zealand and Samoa. The women were shown the same men with full beards and after shaving and asked to rate their attractiveness. The beard did not give an advantage — in the study, women did not find bearded faces more attractive.

But there was another effect. Both men and women rated bearded versions of the same faces as more mature and having a higher social status. Men's faces with beards and aggressive expressions were also perceived as more threatening.

David Poots, a professor of anthropology and psychology at the University of Pennsylvania, explained to Popular Science that facial hair visually enlarges the lower part of the face and jaw and simultaneously signals puberty, strength and potential danger. Therefore, one of the modern hypotheses is that a beard could develop primarily in the context of men's competition with each other, and not solely due to women's preferences.

The more competitors there are, the more beards there are.

Researcher Nigel Barber studied the popularity of mustaches, beards and sideburns among British men between 1842 and 1971 and compared it with the demographic situation. Facial hair was more common during periods when there were more single men on the marriage market.

The authors of more recent works consider this as a possible sign of increased male competition: when there are more rivals, it may be more beneficial for men to emphasize the signs of maturity, masculinity and status more strongly.

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Barber also pointed out that a beard can become more attractive simply because it is rare. In the experiment, the subjects were first shown samples dominated by either bearded or clean-shaven men. A full beard and thick stubble received higher ratings of attractiveness when they were less common among the shown faces.

The same thing worked in the opposite direction: clean-shaven faces were rated slightly higher if there were a lot of beards around. The researchers attributed this effect to the advantage of rare features — an unusual image stands out more strongly from the rest.

A beard is like armor

There is also a much tougher hypothesis: a beard could not only make a man visually more dangerous, but also physically protect his face a little during a fight.

In 2020, researchers from the University of Utah decided to test this idea experimentally. The scientists used a material with mechanical properties similar to human bone and covered it with pieces of sheep's skin with or without wool.

After that, the load was dropped on the model and the impact force was measured. The wool samples absorbed about 30% more energy, and the maximum impact on them was lower. In comparison with the completely hairless samples, the peak impact force was about 16% less.

The authors suggested that dense vegetation could theoretically reduce the likelihood of damage to the skin and bones of the lower face upon impact. However, the study does not prove that this is why humans evolved beards.

Moreover, the scientists used sheep's wool, which is much thicker than human facial hair, so the authors themselves warned that the result should be taken as confirmation of the physical possibility of such a protective effect, and not the final answer to the question of the evolution of the beard.

In a real fight, a beard doesn't give you superpowers.

The hypothesis was also tested in a more practical way. In 2018, researchers examined the results of 600 fights between 395 UFC fighters to see if bearded athletes were less likely to lose by knockout and generally win more often.

No advantage could be found. Having a beard was not associated with fewer knockout defeats, nor with higher combat effectiveness.

The authors allowed for another interesting possibility: a beard may be more a signal of strength than a real weapon or armor, and it can make an opponent perceive a person as more dangerous, even if it does not make him stronger by itself.

A beard is like sunscreen

Facial hair also had a more peaceful advantage. Australian researchers measured the amount of ultraviolet radiation that reaches the skin under the beard and mustache.

It turned out that hair really reduces UV exposure. In the experiment, the UV protection coefficient, depending on the length of the hair and the position of the sun, ranged from 2 to 21, and the effect on hair-covered areas could decrease to about a third of the level of exposed skin.

However, the researchers separately emphasized that protection is unstable and not always high. Therefore, it is impossible to consider a beard as a full-fledged substitute for sunscreens.

Is it true that there are more bacteria in the beard?

Another persistent stereotype is that a beard is automatically dirtier than a clean—shaven face. At least one major study among medical professionals has not confirmed this.

The researchers examined 408 men who worked in two American hospitals. In general, bearded employees did not carry more potentially dangerous bacteria on their faces than clean-shaven ones. Moreover, Staphylococcus aureus was detected in 41.2% of workers with facial hair versus 52.6% of those with clean shaven hair.

There is still no definitive answer from science as to why men need beards. Darwin's version of jewelry that is attractive to women is not completely excluded, and even many studies do show that vegetation affects the perception of attractiveness, and preferences change depending on the length of the beard, culture, and even how often beards are found around.

However, today, more and more data points to a different function. A beard reliably enhances the perception of a man's age, masculinity, social status, and aggressiveness, that is, characteristics that are especially important when competing with other men.