Question: why do men go bald?

Hi – whoever finds out and works out how to stop baldness will become very rich!

Some people can lose their hair through illness, which affects both men and women. Men are more often affected by something called male pattern baldness, which is the ‘normal’ baldness that men get even from their ealy 20s (though there was someone in my school who was bald by 16). Because this is something that we observe in males rather than females, this is apparently largely a sex-linked phenomenon. But since not all males go bald, we can’t say that is purely sex-based. As with so many things it is probably to some degree genetically determined. But it may also serve some function from an evolutionary perspective, as some kind of social cue (like for example a long-lived individual would have needed to be quite smart to live to old age, and the accumulated knowledge of older age offsets some of the loss of physical power of youth. But it is very hard to test things like this, so I won’t go on).

What is a really interesting question in evolutionary anthropology is why humans are hairless. All the other primates are covered in a lot of hair, including the other apes. It is very interesting why humans aren’t covered in hair, and why are we only left with a tuft of hair on our heads (regardless of whether we go bald or not at some point) and some pubic hair which is clearly related to sexual maturity. Some of the hypotheses are that hairlessness evolved as a way of demonstrating our fitness, because it lets other humans see our skin. When we get infections, like parasites, these can have an effect on our skin, and can make us less attractive to potential mates. But for really healthy individuals, showing off your lack of infection would make you really attractive, and you would have more chances for reproductive success.

Other hypotheses for our relative lack of hairlessness include that it evolved for thermoregulation, which is controlling our temperature. As we evolved to stand upright, losing hair and sweating more may have been a good strategy to keep our body temperatures constant. Being upright meant that the top of our heads we exposed most to the sun throughout the day, and so we retained the hair on top of our heads. There are some ways to test these ideas, but at the moment there are no definitive answers. But this is why science is so interesting, we accumulate evidence, and try to ask better questions so that we can find out interesting things like why we go bald!

Log in to Reply