purpose of pubic hair ...

Cecil's Columns/Staff Reports
21

IANAB, but no. Concepts of “less evolved” and “more evolved” imply a directionality in evolution that is not there. Humans genotypically are the one species. We are a different species from our predecessors. That is, we are all much closer genetically to each of the rest of us than we are to any pre H. sapiens creature. Within any species there is a wide range of variation, but that does not mean any one trait in any particular individual makes any individual “closer” to the ancestor species.

This is not like breeding dogs for smooth coats, where within a few generations, one trait is artificially selected, and relatively rapid apparent change (still within the one species) can be seen. Concepts like “throwbacks” are sometimes used in this context where a woolly-coated dog appears after a few generations of selective breeding for smoothness.

All that is happening is that the genetic variability of the group of dogs being targetted for artificial selection is reduced with respect to the genes for coat texture over a few dozen generations. Inevitably, however, the genetic lottery throws up cases of the relatively rare variant which was being selected against. From a breeder’s point of view, this earns pejorative language, because he has artificially imposed arbitrary criteria for desirability on the process. But all the animals produced are still domestic dogs.

We are thousands of generations from our ancestor species. Any variation within humans hairiness has nothing to do with being “closer” to prehumans, no more than being pigeon-toed means the individual is somehow genetically closer to a duck.

22

Whether it’s pheromone secretions, or sweat (or actually both) hair wicks up the fluids and vastly increases their surface area. Ths helps the evaporation of sweat, and exposes more of the volatiles in scents to evaporation too. It also acts like a sponge in catching that sweat so that it evaoprates quicker. Notice that black people, who evloved in areas where evaoporatin is more a necessity than insulation, have frizzy hair on the head too, to assist in the wicking and evaporation process. (I assume - I never asked one what they thought of insulative vs. evaporative properties of afros.)

I suspect hair has evolved along with our upright posture and the human body’s ability to run endurance marathons. That activity can generate a lot of heat, so insulation was an undesirable trait, especially in latitudes where snow does not fall. The result is a compromise. The warmer, less fat-insulated areas of the body have coverings that can both insulate and evaporate, and also some serve as pheromone evaporators.

We don’t have hair on our feet or hands? Ever had an ingrown hair or infected root? The rubbing that happens when you walk or grab things hard would make you prone to infections. There’s a survival advantage in hairless palms and soles. Something that gets 5 minutes workout a week (knowing most married couples’ modus operandi) hair can be a nice chafe preventor. Continuous stressing is not good for hair roots.

As to whether the hairiness indicates evolutionary level? There’s a level of variability in any trait. Some have more, some have less. When the slight difference becomes a selective trait it will become more dominant. For example, in the days of arranged marriages, the woman’s appearance was irrelvant to her ability to find a mate. Now that we have Coors and Budweiser, it still doesn’t matter. Women won’t get prettier - we’ll just consume more beer.

Don’t confuse fertility indicators as in “can make baby today” with fertility indicators as in “mature enough to have children”. there’s a whole different, equally long discussion on the role of recreational sex and why female fertility is concealed. OTOH, the order things appear may have some relevance. Women (girls) tend to develop the outer appurtrenances of womanhood before being capable of bearing children. (Except with modern nutrition, that delay is much shorter) After all, it is was good idea to have ready ahead of time somewhere for the baby to feed in the days before baby bottles. For males, OTOH, the later you could delay the obvious sign that the child was now a rival breeder, the better for his survival.

Whether pubic hair falls out as a fertility indicator was probably irrelevant in the days when survival into your 40’s was a major accomplishment. Even so, there are visible signs of aging that probably compensated for this.

23

I believe that there is hair in the pubic area to keep dirt from getting in. Think about it…anywhere there’s an orifice, there’s hair around it, or the potential (as in mustaches). I don’t know why women don’t have them… something to do with hormones, I suppose. Maybe they had them a long time ago.

katwoman
P.S. I’m sorry if someone said this already. I didn’t have time to read all of them, also sorry about font size. I can’t change it. (Mod note: I did. --Rico)

24

Natural selection doesn’t select for survival, it selects for success in passing on our genes. (Obviously, living long enough to procreate is an important prerequisite for this.) So in principle there’s nothing wrong with saying “This trait evolved because it helped us reproduce successfully.”

25

I have also theorized the correlation between how seed/pollen sticking to fur.

One way plants disperse their seeds or pollen is by sticking to the fur of passerby animals. One of my theories is that this can be the same for pubic hair. Sperm has an uncanny ability to stick to pubic hair–this would seem to be a good way to increase chances for the sperm to reach its target.

Just a theory.

26

Sperm on pubic hair is a lousy way for it to reach its target. It has to get on things that actually get inside the vagina, and then travel up through the uterus to the fallopian tubes. And it’s not like it stays viable for extended periods of time.

27

I agree that insulation is not a function of pubic hair, but your reasoning is wrong. Heat loss is proportional to temperature–we lose more heat through the hottest parts of our body because there’s more heat there to lose. Ignoring all other factors, the hottest parts of our bodies should be hairier, if preventing heat loss is important.

I think the most telling evidence that pubic hair is not for thermal insulation is the fact that when a (naked) cold human curls up, the pubic hair is not on the exterior. It gets folded in on itself between limbs and the body, where it’s not preventing any external heat loss. Hair for preventing heat loss would be on the exterior skin: head, back, buttocks, shins, arms.

28

Hey if it looks like a duck sounds like a duck and flys like a duck…

But seriously I also like the “Filters out dust and debris” idea … I have a lot less dust on my hairy ass then most of my girlfriends. :smiley:

Signed The PhilosoRaptor

29

Female apes (and some monkeys) develop conspicuously hairless genital swellings when they’re sexually receptive, and as far as I know they’re not especially vulnerable to dirt. They seem to reproduce just fine.

Signalling in sexual selection seems to be a better explanation in their case, and possibly in ours (the smelly hypothesis.)