When Did Our Ancestors Lose Their Hair?

[shawnhcorey]

Does anyone have any references to this? I'm asking because it seems to me that when our ancestors' hair started to thin out, they had to start carrying their babies. Their hair was too thin for the babies to grip onto. I'm curious because of an article I read on big babies shaping society where they state that no-one seems to know when our babies started to get big. It seems to me that they could get big if they were relying on their own strength to hold on to their mothers. So when our ancestors hair started to thin out, they had to carry their babies and the barrier to big babies was gone. So I was wondering how far back in time this might be.

[michel123456]

When Did Our Ancestors Lose Their Hair?

That was exactly after the invention of marriage.

[insane_alien]

Our ancestors din't suddently give birth to kids that were bald. it was and still is a gradual process with some individuals being balder than others.

 

There are some very hairy people still around and there are some people who will never really grow much body hair.

 

so the answer should be 'some time in the future'

[JustinW]

Shawnhcorey, You are also basing this on the assumption that this was the reason babies stopped hanging onto there parents after birth. How do we know if it was the same time frame as when the ancestrial paths split between apes and humans? The babies could have already stopped hanging from there parents before the gradual loss of hair do to other reasons.

[Santalum]

Does anyone have any references to this? I'm asking because it seems to me that when our ancestors' hair started to thin out, they had to start carrying their babies. Their hair was too thin for the babies to grip onto. I'm curious because of an article I read on big babies shaping society where they state that no-one seems to know when our babies started to get big. It seems to me that they could get big if they were relying on their own strength to hold on to their mothers. So when our ancestors hair started to thin out, they had to carry their babies and the barrier to big babies was gone. So I was wondering how far back in time this might be.

 

Probably at about the same time that our ancestors became persistence hunters and evolved sweat glands.

 

I believe we are unique in the animal kingdom in having seat glands in our skin that enables us to cool ourselves while still running.

 

All or most other animals have to stop in order to pant or throat flutter etc, as sweat glands would simply not work in a full coat of fur or feathers.

 

Sweat glands give us a major evolutionary edge over them when it comes to hunting and sweat glands are probably genetically linked to hairlessness.

Edited January 17, 2012 by Santalum

[JustinW]

Sweat glands give us a major evolutionary edge over them when it comes to hunting and sweat glands are probably genetically linked to hairlessness.

Good point.

[Dekan]

Perhaps we lost our human body hair, when we started to become very good hunters.

 

As efficient hunters, we readily caught other animals, killed them, and stripped them of their body-hair, or fur. Then used it to make warm coats or clothes for our own bodies. This ability to make warm clothing, must have been a huge survival advantage. Especially in cold regions, during the Ice Ages.

 

The Ice Ages were very strong in Europe. There, people would be glad of warm fur coats. A man who could present such a coat to a woman, would find favour in her eyes. She would regard the offered garment, as proof of the man's hunting prowess. And hence, of the man's fitness to be her mate.

 

Just consider: what was, until recent PC times, considered an irresistable gift, to win the heart of a European woman?

 

Wasn't it - a fur coat?

[Santalum]

Perhaps we lost our human body hair, when we started to become very good hunters.

 

As efficient hunters, we readily caught other animals, killed them, and stripped them of their body-hair, or fur. Then used it to make warm coats or clothes for our own bodies. This ability to make warm clothing, must have been a huge survival advantage. Especially in cold regions, during the Ice Ages.

 

The Ice Ages were very strong in Europe. There, people would be glad of warm fur coats. A man who could present such a coat to a woman, would find favour in her eyes. She would regard the offered garment, as proof of the man's hunting prowess. And hence, of the man's fitness to be her mate.

 

Just consider: what was, until recent PC times, considered an irresistable gift, to win the heart of a European woman?

 

Wasn't it - a fur coat?

 

That 's confusing cause and effect. WE started wearing animal skins because we became hairless. We did not become hairless because we started wearing animal skins.

[JohnB]

I have to agree with Santalum. There is probably a genetic linkage that prevents sweat glands and large amounts of body hair. As one turns "on" the other turns "off".

 

@ Dekan. Even today, few and far between are the women who will say "No" to a mink coat.

[Suxamethonium]

I'm am curious about the sweat glands/loss of hair thing... It seems that it would make sense, except that people sweat under their arms, where there is a significant amount of hair? I've never much been interested in evolutionary biology, but I strayed here, and now I'm curious.

[Sergeant Bilko]

Hormones have a lot to do with it as well, it would be interesting to examine the evolution of our bodies hormonal responses to the differing challenges faced by us as a species through time.

[shawnhcorey]

Hormones have a lot to do with it as well, it would be interesting to examine the evolution of our bodies hormonal responses to the differing challenges faced by us as a species through time.

 

The problem is that no-one knows what those challenges were. The other problem is that things people read in high-school textbooks are taken as absolute truths. For example: we lost our fur so that we can sweat better. There is no evidence that this is true; it's all conjecture. Questions like "Why did we have to sweat so much?" "Where did this occur?" "When in the evolution of our ancestors did this happen?" None of them have answers.

[michel123456]

In relation to another thread: maybe evolution wanted to get rid of us. Maybe we lost our hair because we are degenerated beings, we should have died. Fortunately we were clever enough to wear the fur of other animals and later to use vegetation transforming it into textile.

The other thread is about dinosaurs, maybe they lost their feathers and went extinct before getting intelligent.

Edited January 19, 2012 by michel123456

[shawnhcorey]

Evolution does not have a will of its own and it's not intelligent. Evolution is a process and that which survives does so because of its abilities and is not the will of something else.

[JohnB]

One idea that I did hear on this quite some time ago was different.

 

Our ancestors weren't the big strong cavemen until relatively recently, for most of our history we were more prey than predator. Did we start to have a semi aquatic existence to avoid predators? This would also explain the rudimentary webbing between our fingers and toes.

 

It's just a thought.

[Keenidiot]

One idea that I did hear on this quite some time ago was different.

 

Our ancestors weren't the big strong cavemen until relatively recently, for most of our history we were more prey than predator. Did we start to have a semi aquatic existence to avoid predators? This would also explain the rudimentary webbing between our fingers and toes.

 

It's just a thought.

 

 

Escaping to the water to escape land predators ignores the number of aquatic predators and aggressive herbivores.

 

Many aquatic or semi aquatic mammals retained their fur (like for example otters, seals, ect.) which is part of the biggest claim of the aquatic ape hypothesis. Hairlessness is not linked to being aquatic. If anything, it's linked more to body size and thermo regulation.

 

Our skin doesn't support this idea either. If it were to be believed, we'd see similarities between our skin and the skin of aquatic mammals that provide adaptions to an aquatic life. Yet, we don't.

 

Most animals have the webbing between their digits, this a result of cell death of skin cells that connects digits together at a early stage in development.

 

Aquatic Ape Hypothesis

Aquatic Ape Critique

[shawnhcorey]

Hairlessness is not linked to being aquatic. If anything, it's linked more to body size and thermo regulation.

 

Or it was cause by sexual selection rather than natural selection. That is, our ancestors thought lack of fur indicated a better mate. The question becomes why would that be?

[Keenidiot]

Or it was cause by sexual selection rather than natural selection. That is, our ancestors thought lack of fur indicated a better mate. The question becomes why would that be?

 

My apologies for vague sentence structure. I meant that in aquatic species, hairlessness was linked to size and thermo regulation. Thanks for the correction.

[Moontanman]

Probably at about the same time that our ancestors became persistence hunters and evolved sweat glands.

 

I believe we are unique in the animal kingdom in having seat glands in our skin that enables us to cool ourselves while still running.

 

All or most other animals have to stop in order to pant or throat flutter etc, as sweat glands would simply not work in a full coat of fur or feathers.

 

Sweat glands give us a major evolutionary edge over them when it comes to hunting and sweat glands are probably genetically linked to hairlessness.

 

 

This is easily demonstrated not to be true, ever ride a horse? Horses sweat as do many other hairy and hairless mammals...

[Mike Waller]

This is easily demonstrated not to be true, ever ride a horse? Horses sweat as do many other hairy and hairless mammals...

 

A controversial idea put out about 20 years ago was that the use of fire was the key event; the point being that hairy creatures playing with fire are quite likely to incinerate themselves. Many on the the list I was then on were very strongly opposed to this (to a degree that was well beyond the merits or otherwise of the suggestion) but when I experimentally put a match to the hair on my forearm I was surprised at how much it flared up. I should say that I suffered no permanent harm!

[Tres Juicy]

A controversial idea put out about 20 years ago was that the use of fire was the key event; the point being that hairy creatures playing with fire are quite likely to incinerate themselves. Many on the the list I was then on were very strongly opposed to this (to a degree that was well beyond the merits or otherwise of the suggestion) but when I experimentally put a match to the hair on my forearm I was surprised at how much it flared up. I should say that I suffered no permanent harm!

 

 

Very doubtful.

[Mike Waller]

Very doubtful.

 

Thank you for your detailed contribution to the scientific debate!!!!!!

[Tres Juicy]

Thank you for your detailed contribution to the scientific debate!!!!!!

 

 

I could elaborate by saying that it is highly unlikely that fire and people incinerating themselves could possibly cause enough selection pressure to make us lose most of our hair as a result

 

But do I really need to?

[shawnhcorey]

A controversial idea put out about 20 years ago was that the use of fire was the key event; the point being that hairy creatures playing with fire are quite likely to incinerate themselves. Many on the the list I was then on were very strongly opposed to this (to a degree that was well beyond the merits or otherwise of the suggestion) but when I experimentally put a match to the hair on my forearm I was surprised at how much it flared up. I should say that I suffered no permanent harm!

 

I think this is unlikely. That our hairy ancestors played around with something as hazardous as fire until their descendants could evolved a means to reduce the hazards seems unlikely. It's more likely they would stop the first time they were burnt and their descendants would never need to get less hairy. In other words, our ancestors were pretty much hairless when they started using fire.

[Mike Waller]

I could elaborate by saying that it is highly unlikely that fire and people incinerating themselves could possibly cause enough selection pressure to make us lose most of our hair as a result

 

But do I really need to?

 

It might perhaps be considered a matter of good list etiquette.

 

I think this is unlikely. That our hairy ancestors played around with something as hazardous as fire until their descendants could evolved a means to reduce the hazards seems unlikely. It's more likely they would stop the first time they were burnt and their descendants would never need to get less hairy. In other words, our ancestors were pretty much hairless when they started using fire.

 

I have no strong views either way but was very annoyed on the occasion on which I first hear the idea aired to see the guy who had the imagination to put it forward simply given, as we say, a good kicking for his troubles. This has never seemed to me a good way to progress the scientific debate. There may, of course, be incontravertible evidence of some kind that proves the two events were wholey unrelated; but failing that it seems to me obvious that the interplay between proto-humanity and fire would be a lot subtler that that of the more hairy individuals simply getting burned to death.

 

Off the top of my head I would say that fire confers at least four major advantages: the cooking of food stuffs which, I think, aids digestion; the giving of illumination at night so that work can be done at a time when it would otherwise be impossible; providing some protection against predators who either fear the fire itself or the lighted brands that can be taken from it; and land clearance. Assuming as you say, that hairier individuals, having be burned by it, chose to avoid it altogether, the adaptive advantage on those who decided to stick with it would be substantial, And it would seem to me obvious that the less hairy would be prominent amongst the stickers.

 

Incidental years ago I read a folk tale from China which gave an account of how the Chinese came to eat pork. It turned upon a pre-pork eating society (but why would they have pigs?) in which a particular peasant's pig house burned down. Experimentally trying the meat, he found it so delicious that he had to have more and thus the world received the gift of sweet and sour pork! . Whatever the truth of that, it does seem to me pretty likely that groups of hominids coming across burned corpses following forest fires would find meat not entirely charred very much to their taste and would seek out way of producing this to order. Certainly I have never know a dog turn its nose up at cooked meat.

Edited January 28, 2012 by Mike Waller