Why Haven't Bald Men Gone Extinct?

Lots of men worry about losing their hair. But instead of fretting about their beauty, it might make sense for them to count their blessings — because bald men should probably be extinct by now. So why aren't they?

New Scientist has taken a look at that particularly interesting question in a wonderful feature that tries to get to the bottom of why baldness should still be so widespread amongst the males of our species. From the article:

The hair on our heads may protect us from the noonday sun, maintain body heat when it is cold, and even attract a mate. If so, men who lose their hair are at a disadvantage, and you would expect natural and sexual selection to have weeded them out. So why haven't bald men like me, or at least our versions of genes, gone extinct?

One early stab at answering this question rested on the idea that a man's genetic predisposition to baldness is found in genes he inherited from his mother. Since she would not have suffered baldness and its concomitant ill effects, natural selection would have no cause to remove these genetic variants. But think about it carefully and the logic fails - mothers are just as likely to have sons as daughters and every time they do, if these males are less likely to procreate, these variants should become rarer. In any case, science has shown that this mother-based hypothesis is wrong.

Instead, scientists have recently been positing many theories about why baldies aren't dying out — and most revolve around making some attempt to argue that baldness offers some kind of evolutionary advantage. Some researchers suggests, for instance, that it signals dominance and status, while others suggest that it shows people that they offer maturity, wisdom and nurturance.

Or maybe, just maybe, there's a physiological explanation. One recent study rather boldly suggests that baldness allows more sun to penetrate through the skulls of ageing men, in turn diminishing the odds of developing prostate cancer. That's interesting, sure, but also completely unproven.

In all honesty, nobody knows for certain why bald men still exist, any more than they can account for your pinky toe hanging around. But I can heartily recommend the New Scientists article as a fascinating — and entertaining — journey through some of the more interesting hypotheses. [New Scientist]

Image: Maxim Kalmykov/Shutterstock


Comments

    Isn't a much more simple explanation possible? Baldness usually occurs after the age that one has children. Since the genes have already been passed on, baldness has no effect.

      I was going to comment and say the same thing

      I thought this was the most obvious solution.
      500 years ago most men would have had plenty of kids by the age of 25.

      Was also going to say this, so obvious... especially looking back when people were having kids at a younger age than today

      I was thinking the exact same thing.. I actually thought I'd misread the article, as my answer seemed too obvious.

      Again, the first thing I thought off. The article and study seems rather pointless. Maybe all those sex selection reasons are valid for why we have so few men who are born completely bald or who go bald at a young age- most of those HAVE been weeded out.

      Add to that and 2 out of 3 of the genes confirmed to contribute to the condition are passed on the X from the mother, so this can be passed from daughter to daughter to daughter and a son down the line could get it without a male in the recent ancestry being bald.

    These fluff studies into things like this overlook the excruciatly obvious. Human beings are no longer subject to evolutionary forces and haven't been so pretty much since we moved from huntering gathering clans to settled agrarian communities. Further to that, human beings are immensley complicated - to boil one's chances of finding a "mate" down to a single phenotypic trait is nonsense.
    More baldness allows the sun to penetrate skulls?!? These days I think New Scientist should carry a sticker on the front saying "Warning - No Actual Science Content"...

      skin cancer..

        Generally hits you after your reproductive age - in terms of evolution, anything that affects you after 40 is irrelevant, and as a previous poster noted, until recently you'd start reproducing at 20 or even earlier

    Or alternatively, and certainly my experience, bald men have no trouble procreating, cause there are enough women who aren't worried about (or even prefer) baldness!
    ie the starting hypothesis is incorrect.

      Absolutely this. I started losing my hair at 19. Just shaved my head and got on with life. I've never had a problem attracting women. I'm now married with three children at 38. The starting hypothesis is just silly. Bad science indeed!

    As a bald man I chuckle at these articles...

      Do you chuckle because you have a woman, or because the alternative is suicide?

        Alternative suicide? You my friend are a puppet

    Surely the answer is obvious, every Aussie knows that a bald pate is actually a solar panel for a love machine.

      I wouldnt be sucking much juice then..

    I have a few friends who went prematurely bald, since they have had no trouble getting girlfriends/wives.
    If you want to debate genetics lets talk about why gay men have not gone extinct, since their 'single phenotypic trait' excludes them from procreating naturally.

      mainly because homosexuality isn't genetic.

        Really?

        @ dasg. Exactly. How can being gay be genetic when there are documented instances of genetically identical twins where one is gay and the other is not??

        Although being gay is not a genetic trait, I believe it's an epigenetic trait, whereby gene expression is regulated by factors such as DNA methylation and acetylation. It's entirely possible that genetically identical twins could be exposed to slightly different hormonal environments in utero (particularly if one twin is dominant or there are complications), and in doing so this could affect gene regulation epigenetically and potentially explain how one twin could be hetero yet the other gay. At least that's just my thought on the matter as it explains how being gay is not a personal decision one makes, and yet it's also not genetic.

          Not saying that it definitely is or isn't genetic - but I think you're looking at 'genetic' a little simplistically. What you mean is that it isn't Mendellian.

          Identical twins can both have a set of genes that is predisposing to being 'gay' AND have epigenetic factors applied to one and not the other - I don't think that means that being 'gay' isn't genetic. Just that it is complex.

    Another answer is that humanity has gone soft. using the survival of the fitest theory would also mean that those who do things to get shunned, like steal, murder and rape, would no longer receive the protection from the rest of the group. by allowing these miscreants to survive we are poluting hte gene pool with bad genes.

      "survival of the fittest" is about individuals that best fit the circumstances at the time being more likely to pass on their genes.

      Raping and murdering actually makes it more likely for a individual to pass on their genes, especially in the past when humanity wasn't so "soft". Obvious examples like the Vikings and Mongols found that strategy pretty successful. I doubt there are murder or rape genes though or any "bad" genes really, at least not in a social sense.

    Slap, slap, slap *Benny Hill ;)

      http://www.youtube.com/watch?v=IU28GHMcYxM&feature=youtu.be

    Simple answer is that there is no such thing as natural selection and never has been. Otherwise we'd all look identical and be ultimate humans. If anything there is continually more variance among living creatures, not the other way around.

      It's a long road on this journey, we just haven't got there yet.

      Get 10 people to role a die. Weed out anyone who gets a 3 or lower. Not everyone who's left got a 6.

        So who's been 'weeded out' exactly?

      Mac, your understanding of evolution and natural selection is flawed. When genes mutate, it is a random mutation. Meaning it can be good or bad, or rather regressive or progressive.

      Mutation selection balance:
      Natural selection results in the reduction of genetic variation through the elimination of maladapted individuals and consequently of the mutations that caused the maladaptation. At the same time, new mutations occur, resulting in a mutation-selection balance. The exact outcome of the two processes depends both on the rate at which new mutations occur and on the strength of the natural selection, which is a function of how unfavorable the mutation proves to be. Consequently, changes in the mutation rate or the selection pressure will result in a different mutation-selection balance.

        Sorry to burst your bubble mate but there is not one example of a good, or progressive mutation.

        And your entire second paragraph is just a theory.

        People and animals are born with more and more problems every day. New diseases and disabilities appear at about the rate we cure or treat the last one. We have to be more and more careful about breeding animals like dogs due to so many health problems popping up with new breeds. There hasn't been one single recorded incident of a "progressive mutation" in the history of mankind.

          You don't know your subject. Certain people are born with resistance to certain diseases, people are born taller, shorter, with longer feet, small heads, the ability to live longer, whatever. All these things can help them have an advantage in certain situations, or could be a disadvantage in others. If they prove advantageous in a certain context then the chances that they will carry over in a greater amount than competing traits is increased.

          "Progressive", "positive", "negative" etc. are just different ways of describing things in a subjective way, they have NO bearing on the reality of the genes. Genetics, the universe, natural selection, and evolution doesn't care about anything. Life is not a race to develop the "perfect being", it's simply an uncontrolled on-going process and the only directive is to keep going for as long as possible.

    Errr.. Lots of women folk find bald heads attractive, so they'd be having kids to them.
    And it only takes a few to keep the trait going.
    Really a no brainer!

    It may shock you but some women like bald men, I know it's amazing and I'm the control test.

    I knew it - science is good for nothing. Quick, call the Vatican so they can celebrate!

      If only 'New Scientist' = 'Science', then the Vatican could celebrate.

    First comment nailed it...

    Genetics whatever......

    Random variables are merely another way to say, not enough information....

    Not a lot in our Universe is random.... Its just that there isn't a way to calculate and predict the actual outcome... Hence we deal in Probability, (Apriori, is a guess/prediction, Aposteriori, is the calculation (after the fact)), assuming that all possible outcomes are likely in some determined ratio (probability function).... If we could Directly simulate all of the molecules in the universe (or subatomic particles) and their interactions we could run a computer model of what the universe actually was and in all likelihood, nothing would end up being random... Unfortunately we don't have the "infinite' computing power it would take to perform this exercise... So is Evolution, genetic mutations, Survival of the fittest or whatever, truely random... Probably not. We are still having trouble finding Higgs' Boson.. God knows.

    ill tell you why, because we are f-ing amazing..

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