My head is an evolutionary mystery

I'm a bald man. Aside from a greater-than-average yearly outlay on sunscreen, I like it all right. I can wear hats with impunity, people like touching my scalp for some reason ("It's like a baby's head!"), and I am gangbusters in a wind tunnel. But I would be lying if I said I hadn't gazed skyward on occasion and wondered, "Why me, universe? Why have you chosen me for this unique follicular condition, shared by approximately 25 per cent of men?" But before the universe can answer, my head usually gets to cold or hot and I have to go inside and put on a hat. But the questions remain.

As usual, science is no damn help at all. Over at the New Scientist (registration required), Rob Dunn ask a provocative question:

Baldness is extremely rare in nature. It remains unclear why, and when, our ancestors lost most of their fur but there is general agreement that the few hairy bits we retained serve particular purposes. 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?

My glib response is that I'm awesome, and I can use the light reflected from my scalp to stun predators and escape. But it turns out that no one really knows why bald guys are still kicking around. It was thought for a long time that men inherit the male pattern baldness gene from their mothers. Since the mother wouldn't experience the evolutionary downsides of baldness, they would face no barrier in passing on their genetic material. But as Dunn notes:

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. We now know that a tendency to baldness can be inherited from both parents, though it is not clear what genetic variants are involved. What is safe to say, is that multiple genes influence the probability that a son will one day have to perform a comb-over.

Dunn offers some tantalizing alternative explanations: baldness is an 'authority signal' that denotes dominance and status; it conveys wisdom, maturity, and nurturance to potential mates, useful in producing successful offspring; and it may even prevent prostate cancer by promoting greater vitamin D production through increased sun absorption. I would like to think that all three are true, and that I am shining (pun intended) example of all of them. Then again, there is scant evidence to support these theories, either in the general population or in my day-to-day life.

It could be that baldness is not adaptive or maladaptive at all:

It could be due to genetic drift - the capriciousness by which some genes flourish by chance. Or maybe baldness is not adaptive itself but is instead genetically linked with some attribute of our ageing bodies that is adaptive. The genes that make men bald might also give them super powers of some yet-to-be-noticed variety.

This is a compelling idea, and one borne out by numerous cultural examples: Martian Manhunter, Professor X, and the Bruce Willis character from 'Unbreakable'. There's also Lex Luthor, so, you know, prepare to bow to your bald overlords.

Check out the whole article if you get a chance- it's a great summary of the state of bald science, which apparently is a hopping area of inquiry. We're so vain.

*Graeme may not appear as pictured.