Why are we naked?

steddyeddy

Hey everyone sorry about the title im juust wonndering what are everyones opinions as to why humans have not got the same degree of hair than the other primates? (i know we have more than a chimp say but why are ours more puny).

I have heard various theorys like neoteny or the aquatic ape theory what theory do you most subscibe to or do you have your own?

seamus

I would attribute it to living/sleeping in sheltered dwellings and using animal skin for covering meant that we had an adaptability advantage over other primates.

That is, when it gets hot, an animal covered in hair will obviously find it tougher to cool down than a hairless animal. Crucially, when it rains, a hairy animal will get wet and stay wet for a lot longer than a relatively hairless animal. Particularly if it's cold or windy, this can be the difference between hypothermia and just being cold.
Hairy animals have a biological upper hand in cold weather, but with the use of clothing, a hairless animal like man can level the playing field.

Being hairless alone would not make humans any more successful than any other animal in a given enviroment, but it does make him more successful when the environment changes. Since humans are one of the few roaming primates, this made us exceptionally successful in all our environments, and thus is a trait which has been maintained.

fontanalis

Would sexual selection play a role?

looksee

seamus wrote: »

That is, when it gets hot, an animal covered in hair will obviously find it tougher to cool down than a hairless animal. Crucially, when it rains, a hairy animal will get wet and stay wet for a lot longer than a relatively hairless animal. Particularly if it's cold or windy, this can be the difference between hypothermia and just being cold.
Hairy animals have a biological upper hand in cold weather, but with the use of clothing, a hairless animal like man can level the playing field.
.

I can't see that those arguments would account for us being naked. How do animals survive if their fur/coat is going to cause hypothermia in wet cold weather? Wet fur is better than no fur in cold, wet conditions. Put a naked human and, say, a dog into those conditions and I reckon the human would get hypothermia first. And most animal fur, while it is on the animal, sheds water pretty well.

It seems likely that we were hairy like apes to start with, but our ability to use shelter, fire and eventually clothing could have made hair less important. And as fontanalis suggested, if less hair was considered more attractive then sexual preference would have played an important role.

steddyeddy

Well is it established at what period in our evolution we lost our hair?

rccaulfield

Sexual selection is the best theory for me!

looksee

steddyeddy wrote: »

Well is it established at what period in our evolution we lost our hair?

I have no idea, but its kind of interesting that different races have different amounts of hair, with northern europeans generally being the hairiest (I think) - and men more so than women.

opinion guy

fontanalis wrote: »

Would sexual selection play a role?

Well it does in modern times

fontanalis

opinion guy wrote: »

Well it does in modern times

Hey, leave Cavan women out of this

steddyeddy

Well among mammals were quite strange in the regards that we havent got excessive fur covering our bodies, if we lost our hair before we started wearing clothes that would make sense however i think the date given for when we lost our fur is well before the first accepted date given for wearing clothes.

opinion guy

Ok here is a random theory i've just thought of.

Perhaps by inventing and starting to wear clothes, we could then expend less metabolic energy growing hair/fur, and instead could use that energy for other things like growing bigger brains etc thus giving hairlessness an evolutionary advantage ??

Wibbs

steddyeddy wrote: »

Well is it established at what period in our evolution we lost our hair?

Well one theory has it that the clothes louse evolved about 80,000 years ago so this theory goes we started wearing clothes then. Personally I don't buy it. Recent discoveries of Neanderthal sites have shown the use of pigment as bodypaint. Not much use if one is hairy. Even cooler, they added crushed mica for sparkles like many of the ladies do today. Big jessies they were. If one was found today, he'd likely say "electric light is all very well, but show me to the makeup counter in BT's" Plus it looks like we caught the pubic louse from homo erectus. I'll leave that up to the readers imagination..... Ditto for the head louse. Now a head louse can live in body fur if thick enough, same for the pubic louse, but the differentiation between the two suggests wide open spaces of skin that precluded contact. If this theory is correct we were hairless going back about 500,000 years. Still hard to say. In the case of Neanderthals they had very low body fat and massive muscle bulk. They would make a modern natural bodybuilder look like a weed. Their forearm bones actually curved markedly by the time they reached adulthood from the force generated by their muscle bulk. Muscle generates a lot of heat, so even in a cold climate they would have been warm. Indeed heat may have buggered them up. So chances are they looked pretty waxed.

One other reason for loss of hair could be as a visual sign of health. All over conformity of skin tone and texture shows a lack of parasites and is a good indicator of general health. While beauty is in the eye of the beholder, over many disparate cultures examined one of the biggies is clear skin.

With walking upright sexual and social signalling could be at play. An adult male and female at a distance would be hard enough to make out. The adult males secondary sexual characteristic beard might stand out.

Aside/ What has always struck me as funny and Ive never seen an explanation for this, is the distribution of hair on humans compared to apes. OK pick the hairiest bugger you know. The lad who looks like he's wearing a sweater when stripped to the waist. OK now look at where the densities are higher and lower. Now look at a chimp.

In humans hair is much thicker on the chest, and much lesser on the back, even with "I've grown my own sweater" guy. In chimps and other apes its the complete opposite. They have pretty bare chests and much much hairier backs. I always wondered why the reversal? The male chimp face is pretty hairless too, by comparison to an adult male human(though the hairy lad above has similar amounts of grey in his beard as me ). But then again Asian men would have much less beard growth. Ditto for many african populations. Maybe europeans have it because Neanderthals looked like Ronnie Drew and the first African ladies over to europe thought "hmmm I like a bit of stubble on a man"

seamus

looksee wrote: »

I can't see that those arguments would account for us being naked. How do animals survive if their fur/coat is going to cause hypothermia in wet cold weather? Wet fur is better than no fur in cold, wet conditions. Put a naked human and, say, a dog into those conditions and I reckon the human would get hypothermia first. And most animal fur, while it is on the animal, sheds water pretty well.

Human, covered in clothing wins hands down over a dog in wet weather. It's a trade-off thing - evolution favours those traits which provide the best *general* chances of survival, not specific ones. So if a coat generally keeps an animal warm 90% of the time over no coat, then having a coat is the favourable trait.
If someone then uses clothing, which is 95% effective instead of 90% effective, then those using clothing will survive better than those without.

As someone else mentioned, there then may be more subtle survival traits at play - those who grew less hair conserved more energy and resources than those who grew more because clothing had levelled the playing field, and therefore those with less hair have a better chance of survival.

Clothing alone would be unlikely to be a sole cause. The nature of evolution is so mind-blowingly complex and circumstantial that it's next to impossible to look at a specific trait and map out its development, let alone come up with a comprehensive list of factors which lead to it being favourable.

Apple Butt

I thought the main reason hairlessness evolved was to allow the long distance runner Homo ergaster to sweat and keep cool under the scorching African sun.

Apple Butt

https://www.youtube.com/watch?v=fUpo_mA5RP8

Wild_Dogger

Wibbs wrote: »

In humans hair is much thicker on the chest, and much lesser on the back, even with "I've grown my own sweater" guy. In chimps and other apes its the complete opposite. They have pretty bare chests and much much hairier backs. I always wondered why the
reversal?

I think with chimps , they sleep in a more exposed manner than humans . A chimp will build a nest in the trees , where humans would have sought a more sheltered place of rest and saftey .
And also human would lose hair in areas frenquently covered by clothing etc

Also , the chimp will spend almost 2 years hardly leaving the clutched chest of the mother , and will often spend subsewuent years being carried with its chest tightly embracing the back of the carrier .
So all the time availing of body heat.

Just throwing it out there