How come we have hair on our heads?

Naked ape talking here.

I understand hair on you genitals and under your ams. As they are particularly hot and sweaty places. (Which can be combated with frequent showers and deoderant)

But why did we lose all our hair except for the aformention the top of our heads? What does it serve? Why for that matter did we shead our fur to begin with?

Seem rather odd. We could be growning hair out of our sholders. Why the head? bald guys seem to reproduse well enough.

I believe a lot of heat escapes from the head and hair on the scalp helps us to keep from losing that heat.

Wiki supports the idea that it is a factor in sexual selection:

I was wondering about the possibility of hair being part of sexual display, but that Wiki article lacks the citations.

It hides sticky-out ears.


Whattya mean we?

The hair keeps the top of the head from sunburning as well as losing too much heat. General insulation and protection.

Ok you two. But I have short hair but I don’t have sticky out ears. In fact I put little metal things in my ears just to draw attention to them.

And I could see the sexual thing. But in another universe couldn’t we get just as sexual about shoulder hair? Or being furry all over (but a swear, me and my cats it’s just a platonic realsonship)

And then why is it African guys have dense thick hair if it’s about sheading heat?

And what I really want to know is why we ended up naked except for the three places, particularly the top one, when all of our relatives are furry.

Judith Rich-Harris has a theory:

The link goes to the New Scientist website and features a discussion about this idea.

But why? Whhhhyyyy??? I mean mole rats arn’t very attractivie. Why should a hairless ape be more attractive? And why this stuff on top of our skulls? I want answers!!! Or more fur.

Look, you’re not going to get a straight answer, because while this topic has been theorized about extensively, no one knows for sure.

We have no idea at what stage in the human lineage we lost our body hair, and it is very likely that we’ll never know, because hair doesn’t fossilize. For all we know, only anatomically modern humans were hairless, and neandertals were as hairy as chimps. Or hairlessness could go all the way back to Lucy and the first australopithecines.

My own pet theory is that hairlessness is somehow connected to bipedalism. On the african savanna hair doesn’t protect you from cold, it protects you from the sun. But if you’re bipedal, the midday sun only hits your head and shoulders…so long head hair could protect you from 70% of the sun, and then hairlessness on the rest of the body could allow more effective sweating, humans are one of the sweatiest mammals. We sweat and drink much more than other apes. So maybe increased brainpower allowed our early ancestors to track down and/or store water that would have been unavailable to chimpanzee-level apes.

But this is all theorizing, and we’ll likely never know for sure.

Although I doubt very seriously that Neanderthals were hairless, if the were as hairy as chimps, that might be one significant factor in why there appears to have been little, if any, interbreeding between us and them.

For what it’s worth, most scientists depict Australopithecines as being hairy and show hairlessness (or the beginings of hairlessness) to appear in H. erectus. Recent evidence that H. habilis is not a direct ancestor would put them in the “hairy” camp, too, most likely.

And of course no thread on this subject would be complete without someone noting that we are not “hairless”, but that we just have very short hair. We don’t have significanlty fewer follicles per sq inch than other apes.

Well of course I’m not going to get a straight answer from a lemur…you already have fur.

But I still want to know why we have this stuff on the top of our heads. And just (almost) there. I mean black guys tend to pull off bald better than anyone. Why just our heads? Why not our bipedal shoulders?

Ah, just another question I’ll have for god right before he thows me into an abssy of eternal suffering. Makes note

I would agree with our prosimian friend about the basic reason for hairlessness: it is most likely associated with the human adaptation as a diurnal cursorial hunter in tropical savannas. The hairlessness plus abundant sweat glands help us shed heat when running in strong sun.

The brain is susceptible to overheating. I think under the given conditions it may have been more important to protect the top of the head from direct sunlight rather than for it to become hairless and shed heat directly. Most of the excess body heat can be shed from elsewhere in the body.

The shoulders may lack hair because 1) it is not nearly as crucial to protect them from overheating as it is the brain; 2) they may have been partly protected by long head hair anyway.

While this may have been the original reason we retained hair on our heads when we lost it elsewhere, I suspect there may have been subsequent selection for it as a species recognition signal and a sexual attractant. The latter may have become much more important once we adopted artificial ornamentation and clothing.

Of course all this is entirely speculative; as has been said we lack evidence for any of this.

After much research, it looks like there might be an answer.
If you though it was to keep your brain warm, your probably wrong.
From what I can tell, we have disabled powers, like telepathy and the hair has something to do with how these powers work, like antenna of some type.

I’m not sure reading the story of Samson should count as research.

(Shush, I know he wasn’t telepathic but come on, superhuman strength surely counts)

If anything, hair blocks this ability.
Ever notice how all supervillains are bald? And how about Dr. Manhattan?

Unfortunately, I have a lot less of it than I did in 2007!