The theory is being proposed by a new study that found the more competition a man has to deal with, the more flamboyant he gets - at least in the world of primates.
Dr Cyril Grueter from the University of Western Australia said this was especially the case in big, multilevel societies where male primates have developed more ostentatious "ornaments".
These include the elongated noses of proboscis monkeys, the upper-lip warts in golden snub-nosed monkeys, capes of white and silvery hair in hamadryas baboons - and beards in humans.
At least some of these badges may enhance male sexual attractiveness to females.
For instance, male rhesus macaques with darker red faces receive more "come-ons" from more females during the mating season.
But as well as aesthetics, male-male competition could even be a stronger reason for the evolution of badges.
The researchers believe men with beards could be seen as more aggressive and dominant - and might also be attractive to women drawn to seemingly powerful men.
In their study of 154 species of primates representing 45 genera, the authors flamboyant badges were of benefit to males in large and complex social organisations to signal their identity, rank, dominance and attractiveness.
Species that live in smaller groups, on the other hand, had less need of badges as individual recognition and more frequent interactions allowed animals to better assess the social status, strength and quality of their contemporaries.
The authors explain that primate group-sizes vary dramatically: Bornean orangutans are non-gregarious, whereas mandrills move in hordes of up to 800 animals.
The team found the popularity of moustaches and beards among British men from 1842 -1971 rose when there were more males in the marriage pool and beards were judged to be more attractive.
"When you live in a small group where everyone knows everyone because of repeated interactions, there is no need to signal quality and competitiveness via ornaments," said Dr Grueter.
"In large groups where individuals are surrounded by strangers, we need a quick reliable tool to evaluate someone's strength and quality, and that's where these elaborate ornaments come in.
"In the case of humans, this may also include phenotypic extensions such as body decoration, jewellery and prestige items."
Scientists reveal the maths behind beards, man buns and bicycles
Bearded hipsters, with fix gear bicycles and hand-knitted beanies, seem to be everywhere.
While they may strive for individuality, they have instead been caught up in one of the greatest mysteries of our time; the hipster paradox.
Now mathematicians believe they have developed an equation to explain why the phenomenon takes place.
Professor Paul Smaldino, in a paper just published in the journal Royal Society Open Science, has created a model of how human behaviour always ends up in "collective conformity".
The University of California professor discovered our common desire to be different means we will always converge toward conformity.
The only exception is when our definition of "different" varies widely from one person to another. In this case, everyone splits off from each other other time, with no conformity taking place.
Last year, Professor Jonathan Touboul, a mathematical neuroscientist at the Collège de France in Paris developed a similar equation to explain the "hipster paradox."
He claims there is always a delay between the time a trend begins to gain traction, and the time hipsters begin following it.
This delay is caused because people can't be aware of what others are deciding, in real-time. As a result, hipsters gradually realise that the trend, and the decision has been made while making the same decision separately.
This leads to them gradually conforming towards what then becomes the mainstream.
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