Why is human hair so wild?

[blutoski]

One important thing to remember when considering evolutionary 'stories' for human features is to be mindful that we have been evolving while developing technologies, rather than developing technologies only after becoming anatomically modern.

Hair could have evolved like this because we already had the tools necessary for maintenance (fire, twine, blades...) and it's not unlikely that the decorative application fed into sexual selection.

Observe that Australopithecines were tool users, too. The ability to cut long head hair became part of our technological inventory millions of years before the emergence of long head hair itself.

Myriad mentioned dog breeds, but this is a bad comparison - dogs are intensely domesticated, and cannot be considered an example of a wild type species.

They're a better example of domesticated species like humans: dogs get poor eyesight; wild Canus spp do not. It's a property that emerged in the familiaris species over time because pre-existing technology mitigated the consequences and it was not continuously culled out of the allele pool.

 

[Verde]

A mutation to have long hair would result in more interest from males.

More to grab on to, to drag the woman around.

Or is that just a caveman stereotype?

V.

 

[HansMustermann]

Just caveman stereotype.

You'd actually get a proper civilized kidnapping at dagger point by a warrior, and be informed that now you're his wife and have to gather berries for him and supply sex on a regular basis. Nothing as messy as being bonked on the head and dragged by the hair. I mean, good grief, you wouldn't want to damage a perfectly good piece of nookie in a society which has a chronical shortage of it

 

[blutoski]

More to grab on to, to drag the woman around.

If I had to guess, I would speculate that it was females attracted to males with full heads of hair, rather than men attracted to women with long hair.

Male pattern balding is a sign of senescence. Long hair may be an unconscious indicator of youth.

 

[John Jones]

Evolution my dear males, in humans, is a function of desire as much as utility.

Male scientists, they don't understand the source of human evolution.

What species of male scientists are you referencing?

Male scientists of the species homo sapiens sapiens seem to have a good grasp of human evolution.

Aside: It's considered polite to refer to adult males of the Homo sapiens sapiens species as 'men'.

 

[r-j]

Isn't long hair on the head an advantage? Because of our large brains? And the fragility of our skulls?

 

[Illustronic]

It's like wondering why a rich man's daughters are so good looking. Ever notice that?

It happens so often, with such regularity, you might think there is some natural selection going on.

The rich guys land the foxy babes. That's not science.

 

[r-j]

You think it's a new thing?

 

[Elaedith]

Hair doesn't stop growing, but it does reach a maximum length, because each individual hair follicle only grows its hair strand for a certain time and then enters a dormant cycle that causes the strand to fall out. The duration of the cycle and the rate of growth differ on different parts of the body.

Some dog breeds such as poodles and miniature schnauzers also have hair that grows long unless cut (and not just on their heads but on their entire coats), which clearly would be a disadvantage in the wild.

It appears, therefore, to not take much of a genetic leap to cause such changes in hair growth behavior, which is not surprising considering that only a timing factor has to change. The change in some dogs happened during the span of recorded human civilization, so it wouldn't be surprising if changes in humans have occurred in the longer time period during which humans have had knives.

Respectfully,
Myriad

And not just dog breeds either.

http://www.flickr.com/photos/bivoir/313539556/

 

[HansMustermann]

Isn't long hair on the head an advantage? Because of our large brains? And the fragility of our skulls?

That's a fascinating idea. Please elaborate.

The way I know it,

1. The human skull isn't particularly fragile. E.g., one reason why brain-damage and even deaths in boxing rose dramatically after they added gloves, was that previously people actually avoided punching at the head or jaw. You can supposedly actually break your hand by punching someone in the head.

Of course, it's not hard as in "will stop slap from a grizzly bear", but still...

2. The skull is actually not all that important there. One can sustain severe, and even lethal, brain damage without the skull even cracking. I mean, it's important as in, it's some protection, but you'd need a whole more cushioning to actually avoid damage when it goes all the way up to a broken skull.

3. Hair doesn't actually cushion blows all that well. To paraphrase the Billy Connoly skit about airplanes, I don't think I've ever heard in the news "an unknown assailant tried to mug John Doe at a heavy metal concert with a brick in a sock. Luckily John Doe had long hair and damage was minimal"

4. The other problem is that it doesn't cover the front part, where actually impacts are more likely in a fight or even when tripping. So if nature actually intended it as some protection, it sure made a ridiculously poor job of it.

5. Actually it seems to me that for cushioning blows, length would be rather irrelevant past a relatively short length, wouldn't it? If it's going to cushion an impact to the head, whether you have hair down to your shoulders or down to your knees, won't actually make much of a difference. If the purpose was to cushion blows, density of hair would have been more important than length.

Of course, that's just my personal opinions and I could be wrong. If any evidence points otherwise, I'm fully prepared to learn.

 

[r-j]

it would only take a minor mutation for such a thing to happen and that because it did happen in a species that happened to have technology to control it there wasn't any natural selection pressure to get rid of it--I really couldn't think of a reason why natural selection might have led this to happen in the first place.

Why is it assumed long hair happened after civilization? Is there any evidence that early humans didn't have long hair?