I don’t remember when, but at some point in my life I was taught that the places on our bodies that had dense hair, armpits, pubic and head, were the places that our bodies lost the most heat and the hair acted as insulation.
So when humans are young they have a a high SA/Vol ratio, and this is the time of life when hypothermia is the greatest problem. At this time they have no hair at all.
And when they become adults their SA/Vol ratio is small and hypothermia becomes much less of an issue. And at this point there is suddenly an evolutionary reason to develop insulation.
Does this sound plausible to anybody?
Seriously. Do the people teaching this stuff not understand that children lack pubic hair? Any explanation needs to account for that fact. The idea that children some how have less need for insulation than adults just boggles the mind.
This is no explanation at all.
How does this explain the pattern of hair growth, both temporally and geographically? How does it explain the unique features of pubic and axillary hair?
Why did our ancestors develop this trait? That is the question at hand. Saying that they did develop it is not an answer.
**Blake **- Can you answer this?
Nope, but the fact that I have never heard of it suggests that it doesn’t exist.
Other primates don’t usually have anything like our pubic hair. They are more likely to have hair there that’s finer than elsewhere on their furry bodies, or even be conspicuously bald around their genitals.
Yellow-tailed woolly moneys (rare Peruvian species) are described as having pubic hair - in their case it’s long, luxuriant, and brightly colored. Both males and females have it.
Does that work for anything? If so, I don’t think we need the rest of the internet.
Unfortunately it only works for topics that I keep some sort of eye on.
It’s a bit like asking an avid dog lover if she knows whether salmon can poison dogs. She almost certainly won’t be able to give you a definite answer, simply because it’s hard to prove a negative. But the fact that she has never heard of such a thing before is itself indicative that it’s not true, since if it was true it’s the type of thing that would be be common knowledge amongst dog enthusiasts.
Evolution doesn’t really work like this. It’s not like some cave man noticed he had no pubes and thought to himself - boy, it’s sure chilly down there. It’d be awfully nice if we spent the next million years gettin some bush going. And, then, blamo - pubes.
Mutations occur randomly. Traits that are beneficial have a good chance of sticking aorund because they help the mutant survive and breed. Traits that get you killed tend to get weeded as the bearers don’t live long enough to breed as often as those without the trait. Traits that are neutral - well - sometimes they stick around and sometimes they don’t. So, it may be that pubes helped some dudes get funky and they stuck around - or it could be that the genes are tied to something else that’s beneficial - or it could be that Johny No Pubes got hit with a brick. World may never know.
How could an individual develop pubic hair in just one generation? It’s not like the difference between pubic hair and no pubic hair is a point mutation.
You may be taking that sentence too literally.
It’s a mistake to assume that every human genetic trait appeared because it provided an evolutionary survival advantage. Traits are simply the result of mutation or genetic drift, and remain because they didn’t kill people before they were able procreate. But that doesn’t by any means necessarily indicate that all genetic traits actually enhanced survival or made it more likely to reproduce successfully. Many do, but not all.
‘Why’ is the wrong question to ask about these things. But it’s reasonable to ask ‘What reproductive advantage do we gain by having pubic hair’ instead of ‘Why do we have pubic hair’. Now when you mention pubic hair people immediatly think of hair around our naughty bits, and that leads me to believe it is no accidental trait. Sexual selection and fruitfulness are primary evolutionary forces, and I suspect that is the reason. Why pubic hair makes one more sexually attractive is hard to pinpoint. Modern people have different attitudes about this, but our ancestors, naked on the plains, may have found pubic hair to be a better identifier of reproductive success than the unadorned genitalia found in contemporary pornography. It could all be about dispersal of scents, or covering up our shortcomings instead, but one way or another it’s likely to be about sex. I don’t see any convincing evidence that pubic hair makes people more intelligent or better hunters.
Of course there’s an argument for an accidental trait also. The genetic changes that gave humans finer hair than our ancestors, may have had left certain areas unaffected. It certainly left plenty of hair on top of our heads, and plenty of other hair develops with puberty. So it may have been a mutation that reduced our hairiness in the first place, which was unable to work sufficiently to keep hair growth down post-puberty.
In that case the post makes no sense.
I’m sorry, but you are partially mistaken. Women grow hair there just as they do here. A large subpopulation has much finer hair on their legs than is typical of humans in general, but they all have it. What you are claiming is nonsensical, like claiming that children have no leg hair. It is just not dark and coarse. Those asian and Japanese women that do have coarser body hair do not have a cultural need to remove that hair with razors, however. When removing the hair, they tend to sand with paper strips designed for the purpose, thread their hair, or sugar/wax. There are entire salons in Japan dedicated to the sanding of the body and other hair removal procedures. Laser hair removal has become very popular in recent years, as well, in Japan. Traditional methods of hair removal such as sugaring, threading, and sanding have been around in the near, middle, and far east for many centuries. Fastidious removal of body hair also sometimes has religious significance, especially in regards to cleanliness or purity.
To add:
In the interests of accuracy, the only locations on the human skin that lack hair of any type are the palms of the hands, the soles of the feet, the lips on the face, and portions of the genitals. Saying that someone doesn’t have hair on any other location indicates either the removal of that hair or a genetic anomaly. What I believe most people are trying to say is that the body hair on the legs or other locations for certain non-shaving individuals or populations is pale, short, and fine, like the hair normally on the back of one’s hand.
OK.
"Various theories have been advanced regarding the purpose of pubic hair. For example, I have a Smithsonian monograph — nothing like a little light reading in the john — that presents the thesis that pubic and axillary (armpit) hair gives babies something to grab onto. True, my baby does this, but she’s 27 years old.
Others think pubic hair helps retain glandular secretions that are a powerful aphrodisiac. According to the nation’s monkey testers, armpit perfume has a direct stimulatory effect on the primate libido. Undoubtedly explains why your SO is driven wild with desire when you come in smelling a little ripe."
— Cecil Adams
Personally I think smell is big with us primates—It’s just that most people don’t talk about it or maybe even think about it. We are ‘trained’ by society to consider the armpit a dirty thing, but y’know (provided he’s fairly clean) there is nothing like nuzzling up to my hubby’s glandular areas and that scent—it really turns me on. When he’s been gone for a couple of days I grab his pillow and I can at least feel like he’s there with me, by his scent.
Here’s a way to explore scent–Why do we say ‘Just not the right chemistry?’ Have you ever met someone who was attractive, nice, smart interesting and yet that “Chemistry” wasn’t there.
Or this—Somebody who isn’t really great looking, okay personality, but not stunning, not that witty or brilliant, yet every member of the opposite sex seemed to chase them. Was it something we couldn’t see about that person, did they just smell hot?
[quote=“Knorf, post:72, topic:349490”]
It’s a mistake to assume that every human genetic trait appeared because it provided an evolutionary survival advantage. Traits are simply the result of mutation or genetic drift, and remain because they didn’t kill people before they were able procreate.
[quote]
Mutation and genetic drift are not the primary factors maintaining traits in populations; selection in many cases is far more important. And so it makes sense what selective forces caused a trait to develop and become widespread in a population; or conversely, what selective forces maintain it afterward.
There are some traits that may effectively be “neutral” with respect to selection. But in such a case you would expect fairly random variation in the presence or absence of such a trait. Since nearly all adults in most human populations develop pubic and axillary hair, this suggests this is not a neutral trait.
How did the trait appear in the first place?
Why does it persist?
My only argument is that pubic hair could well be a “neutral” trait, and I would add that the ubiquity of a trait is not necessarily evidence that it was selected for.
Absent a compelling explanation–and none in this thread qualify as compelling in my layman’s opinion–I remain skeptical.