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‘Showy’ big beards linked to having smaller testicles

‘Showy’ big beards linked to having smaller testicles

A model with a beard has fun with a friend

A new study undertaken by researchers at the University of Western Australia and the University of Zurich suggests males with ‘showy’ masculine attributes, such as beards, may have smaller testicles than the males of other species.

The study explored the link between the sizes of testicles and other physical male attributes linked to mating.

Across the animal kingdom, many male animals compete for females when it comes to mating. Some males of their respective species fight over females. Because of this, the size of their antlers or teeth may be of great relevance.

Other alpha males will demonstrate their superiority to others by growing large manes or other attributes specific to their species.

For example, male proboscis monkeys with larger noses have a greater number of female partners than those with smaller noses.

However, this doesn’t mean males lacking these attributes never get to mate or pass on their genes. The researchers say that one way of competing is to produce more sperm. Producing more sperm increases the likelihood of a male passing on his genes and fathering offspring. To produce more sperm, their testicles may be larger.

They conclude that male primates are likely to be, ‘Well-adorned or well-endowed – but not both.’

Conserving energy – big balls or thick beards

In short, developing large testicles and growing showy alpha-male traits – such a lots of body hair and big, thick beards, may take up too much energy. Species will go for one or the other.

‘And if males can’t keep other males off their females,’ says a press release from the University of Zurich, ‘they will try to outcompete them at the level of sperm. By swamping the sperm of others, they can increase their chances of fertilization. But producing a lot of sperm requires large testicles.’

‘Ornament elaboration comes at the expense of testicle size and sperm production,’ says one of the study’s authors, Stefan Lüpold. ‘In a nutshell, the showiest males have the smallest testes.’

Although the bulk of the research looked at primates such as monkeys, the study also looked at humans. It drew upon previous research that suggests ‘men with more masculine faces are perceived as being more attractive and report a greater number of sexual partners than men with less masculine faces.’

‘Big testicles come with large weapons but less ornamentation,’ says Lüpold in a press release. ‘It’s hard to have it all.’

It’s uncertain how the research might be impacted by factors such as fashion and culture – both of which can influence whether humans grow beards or not. Gay Star News has reached out to Lüpold for further comment.

UPDATE: 11 April

Researcher Stefan Lüpold responded to questions from Gay Star News about the study.

‘All our analyses, and so our results, were across species, not within species. We basically had average values per species for all our traits. In this regard, we did not compare men with or without a beard. We focused on variation between different primate species.

‘What our results show is that species with exaggerated badges of status have smaller testes than species that are less adorned.’

Asked about how humans differ to other species, in regards to the reasons they grow bears, Lüpold said we do different to other species but our evolution also makes comparisons valid.

‘Today’s humans are certainly different from other primates in many ways, particularly in terms of beards in the context of religion or fashion.

‘But we need to consider how long we’ve been around and when we started shaving our facial hair. For much of our history, men didn’t shave, and this is a crucial aspect.

‘Finally, in the context of our study, the mere fact that men naturally grow a beard (whether or not they shave it), whereas women don’t, makes this trait comparable to other hairy traits in other primate species.

‘Culturally we have also moved away from just relying on body adornments in our mate choice, using all kinds of materialistic objects to woo partners or express status and power among men. So yes, we are different, but the evolution of beards most likely followed similar rules as the evolution of manes, capes or other hair tufts in primates that are expressed by males but not by females.’

See also

Meet the Mexican artist who loves drawing hairy men and penises

Gay rugby players go naked to raise awareness around testicular cancer

14+ photos of bears, bears and more bears at BeefDip in Mexico