Why did humans evolve long hair?

Hi, I’m not attacking the theory of evolution - I’m not a creationist any more.

Anyway, people’s body hair is generally thinner and less pigmented than apes body hair. But what about head hair? What is the survival advantage of having some hair that is about 90cm in length? And some people have extremely thick head-hear - they would have an “afro” if they let it grow freely.

Did it evolve to make males or females appear more attractive? Well I guess females do appear more attractive with long hair than with ape-like hair… though that doesn’t explain why males have long hair as well.

I saw show about human evolution on Discovery that said when we started walking upright we lost our body hair to cool us down better but kept our head hair to protect our heads from the sun.

It started as just a little mutation, but when nature tried to change it back, she COULDN’T, because they looked to fantastic!

I am not really sure, it could be because since we lose a lot of heat through our head, we required more hair to keep us warm. Or it could have been religious. ;j
Give me a head with hair, long beautiful hair…

Someone brought this up before, but I guess that was one of the threads that disappeared in the Great Hacking Incident. Anyway, in addition to the aforementioned protective functions, what we came up with was something like, “Hello, look at my long beautiful hair, proof that I manage to consume lots of nutritious food in this hostile environment, God what genes I have, come mate with me!” An over-simplification, but not by much.

I wonder if we start going bald and/or gray because at that point most of us are around the age when creating offspring would be more likely to have birth defects of one kind or another? Just a thought.

quick google yields

http://www.keratin.com/aa/aa004.shtml (keratin.com?)

Mephisto has it. Long hair is a hassle if you are struggling against nature to survive. It gets in the way. It hides nits and other infections. It requires nutrients if it’s not going to look disgusting or fall out.

So if you have beautiful long hair you must be doing well for yourself, whether through youth, health, genes, environment, status or whatever. An ideal mate.

The idea arose from study of the evolution of the birds of paradise in Papua New Guinea. They are an extreme example. The colours and feathers these birds have would, you’d think, be a distinct disadvantage to survival. Yet for some reason rather than being evolved out, they had got ever more elaborate and ridiculous. This was particularly the case with male birds. It was concluded that these features survived and thrived because it allowed the male birds to show off and attract mates. What they were saying by bearing these colours and feathers was “Look how strong and healthy I am. Despite having all the overheads of maintaining all these fine feathers and standing out in the jungle to all preditors like a beacon, I am here and in fine fettle. Mate with me and you will have top-notch offspring.”

Things are a little more involved and complex in human behaviour and evolution, but long hair works in much the same way.

If you don’t comb and wash your hair, doesn’t it soon form dreadlocks and pretty much stop growing? In pre-comb times (when we did most of our evolution) I don’t think people had long and flowing hair, even if they were in good health.

Also, what about blacks? Their hair in it’s natural state doesn’t get long like that. It basically just provides some cushioning for the head and helps to radiate heat.

I think humans probably started off with hair much like modern blacks, since we evolved in Africa. Some of us migrated to colder climates where straighter hair was an advantage as it was better at trapping heat and keeping your head warm (VERY important, we lose a large percentage of our body head through our heads).

Well what about beards then…? They can also grow to long lengths, like head-hair. And they can get in the way of your mouth if you have a curly beard and irritate your lips (until your skin gets used to it). It would be a sign that the male has hit puberty of course, and there are other signs like armpit hair and pubic hair. What is the survival advantage of arm-pit hair? And chest hair?


Well many animals, like camels, seem to have quite thick hair and yet they don’t have much trouble coping with a lot of heat. And a full head of hair is a lot of extra baggage. It grows to about 90cm so it would weigh quite a bit. And if you look at blacks on documentaries, you’d see that they cut their hair super-short… I think this keeps them much cooler. (Thick head hair just traps heat I think). Anyway, they do fine without 90cm long hair and by looking at them you’d never know that they are capable of growing long hair. In the Islands they grow their hair longer and they grow it the longest where people have thin hair (American Indians, etc) - well something like that.

Obviously Badtz Maru never saw Clan of the Cave Bear. :slight_smile:

Seriously though, Badtz Maru has some very good points. However, I still suspect that the mating aspect has more to do with our long hair than anything else, mostly for the reasons Futile Gesture mentioned. I imagine that we’ve been grooming ourselves for longer than most people think. And even before the days of the comb, we might have tried to pick the snarls out with our fingers. I know monkeys and some other apes have something akin to grooming behavior, although in their case I think it’s more a matter of picking tasty little bugs out of their hair.

Regarding the comment about early African humans having kinky hair like modern black people–why? I’m not being argumentative (at least not on purpose), but am seriously interested. The other primates, as well most modern human ethnic groups, have straighter hair. Couldn’t kinky hair have appeared on African heads after we started moving into other parts of the world? It’s too late for me look up any evolutionary charts or early human migratory maps in an attempt to figure this out (and perhaps disprove my idea), but I don’t see why the first humans necessarily looked like the majority modern Sub-Saharan Africans.

Yeah, it naturally forms dreadlocks though I don’t think it stops growing. I’ve seen people with quite long dreadlocks and I think those with shorter dreadlocks haven’t been growing their hair for long or have trimmed it.

Well maybe using your fingers makes a fairly good comb. And apparently homonids have been using stone-age tools for about 2 or 2.5 million years…

Those in Africa would cut their hair - probably because it is too hot and hard to maintain. (Water is often scarce) I mean the hair of African Americans grows long if it isn’t cut and their ancestors lived in Africa a few centuries ago.

Yeah it can be a pretty good cushion but I think it just absorbs heat… I mean people I’ve known with long hair often complain about the heat and then have their hair cut short. And I’ve had longish thick hair and have been almost bald in hot weather and it is better being bald… the sweat can evaporate on the skin and I can feel breezes straight-away. Shortish hair (like many Africans have as well as animals who live in hot weather) would radiate heat, but not long hair. I mean in Australia all the mammals have fur even though many of them live in very hot harsh environments.

I think you are all looking at it wrong. Not every trait that an organism has HAS to be benificial. We only loose traits if they somehome impeed passing on that gene.

Changes don’t occur to “help us” or for some purpose. They just happen. If the organism that has that change is able to reproduce, regardless of whether the trait is good or bad, then the trait may survive.

Long hair very well could have been a mutation that didn’t help us at all, but was very dominant genetically, so it spread fast.

Evolution doesn’t always only make “the strongest” survive. Look at panda bears. They are built to do one thing. Eat Bamboo…BUT bamboo isn’t very nutritious to them, so they eat it all day. if a virus came in and killed all the bamboo…dead pandas.

Cecil Adams on How does body hair know it’s been cut and grow back?

Theory 1: We used to live in trees (picture Tarzan). Kids were likely to fall since they’d lost their prehensile tails. Long hair provided a great means for Moms to snatch their kids out of mid-air as they fell.

Theory 2: We used to live in the water (so says the Aquatic Ape Theory). Kids would start to drown because they’d lost their webbed feet. Moms would use the long hair to snatch them up out of the water.

::ducks and runs::

My hair’s about two feet long, and very curly. I haven’t used a comb or brush (or hairdryer) on it in five years. I just use my fingers. No knots, no dreadlocks, just long, thick, beautiful hair. The babes love it. :slight_smile:

I was gonna add a nitpick, but I see sghoul beat me to it. Still, it bears repeating, because it’s gone otherwise unremarked in the thread.

Evolutionarily speaking, just because a trait exists doesn’t mean there has to be a reason for it. There just has to be a lack of a reason against it.

Male pattern baldness in humans, for example. If you buy that it makes the sufferer unattractive and less likely to reproduce (which is by no means a certainty), you may wonder why it arose in the first place. But if you notice that most men have reproduced by the time the baldness becomes really noticeable, then you realize that it provides no barrier to reproduction, and that therefore there’s no reason it should be selected against.

So even though the comparison to the bird of paradise is valid, it isn’t necessarily the case that long hair in humans serves and is reinforced by a positive evolutionary purpose.

Carry on.

Elaborate facial and head hair and other facial adornments are typical of many primates, not just humans. Most likely these characteristics are there because they assist in species and individual recognition, or function in sexual selection. Human head hair is probably no different.

Check out some of these:

Emperor Marmoset

Golden Lion Tamarin




Thank you, that is the funniest critter I have seen in a long time.

I signed up to post this.

I am a caucasian man and I lived out in the woods for several years during which I didn’t cut my hair and only washed with lake water, didn’t brush my hair and it grew perfectly straight and un-knotted. I massaged my scalp regularly and ran my fingers through my hair to spread the oil around.

Dreadlocks and knots actually appear actually caused by washing with hot water and/or soap. Since my hair has the natural oils it doesn’t knot up at all. When I came away from living in the woods to work on a farm instead, at first I would wash my hair with warm water, and very quickly it started knotting and snapping, and lost its sheen and colour. It was quite upsetting for me. The hair also became loose/separated and got in my eyes and stuff, and since it snapped easily there were short bits which wouldn’t tie back.

Now I just wash it with luke-warm water and keep soap away from it, and it is starting to get its colour and sheen back very slowly, whilst knotting and snapping less and less.

With the natural oils I expect I can synthesise vitamin D in my hair, which would be one advantage, especially since most of our skin is covered up by clothes. Furry animals synthesise vitamin D in the oils on their fur.

I really have long hair just because ‘what if’: what if there is some benefit to having it which outweighs the downsides. I’ve chosen to take that gamble so far. I’m a logical, scientific person, but there has just been virtually no study into possible benefits of long hair. Since I was into the natural stuff, growing long hair seemed an appropriate thing for me to try out.

Does zombie hair continue to grow?

“Aquatic Ape” is a hypothesis, not a Theory.