Why Do We Still Have Pubic and Armpit Hair?

Stefan asks: Why do we still have pubic and armpit hair when we lost most of the rest of the hair on our bodies? What purpose does it serve?

armpit2It’s a biological mystery that has perplexed humanity through the ages – especially in recent times when so many of us go to such great lengths to remove it. What useful purpose could pubic and armpit hair possibly serve? Is it just Mother Nature playing a sick joke on us? Does she own stock in Gillette?

Although there’s no definitive answer, plenty of theories abound as to why human beings have hairy armpits and pubic regions, one of which seems pretty reasonable.

One theory that’s not quite as reasonable, though still slightly plausible, is that the hair’s purpose is to reduce friction. Skin constantly rubbing against skin can cause major discomfort to our sensitive bits, and armpit hair is thought to act as a barrier against such rashes and irritation and perhaps even reducing the chances of acquiring an STD by providing something of a buffer. Sounds logical enough, but how many people complain about armpit irritation that is not caused by shaving itself? And the STD thing doesn’t really come in play with the pits… at least, not in most cases. (We don’t judge.)

As far as pubic hair acting as friction protection during sexual intercourse as some suggest – it would take an awful lot of, um, enthusiastic sex to warrant a permanent buffer. If this is necessary in your case, we at Today I Found Out salute you.

Another suggestion as to the reason for pubic hair in particular is that it acts as a genital blanket of sorts. This seems plausible until you consider the location of male pubes, which really don’t keep the important bits all that cozy. Also, females would have hairy lower torsos to keep their internal reproductive organs toasty, and that’s not the case, thankfully.

It seems Mother Nature did a great job of providing women with perfectly placed pubic hair to keep dirt from entering the vagina, but the guys have no such protection around the urethra. At least for females, genital tresses perform the same protective function that cilia do for the nose, and brows and lashes do for the eyes.

But, as with many things in nature, the leading theory as to why we still have pubic and underarm hair is to increase the chances of getting lucky. This is perhaps backed up by the fact that unlike hair on your head, armpit and thick pubic hair tend to show up during puberty, around the same time your apocrine sweat glands become active and begin secreting an oily substance containing a variety of proteins and the like. These apocrine glands are, among a few other places, concentrated in your armpits and genitals, unlike your other main type of sweat gland, eccrine glands, which are distributed pretty well throughout your body. Pubic and armpit hair also usually begins to thin out significantly starting around when people hit their fifties, perhaps another indicator it’s all about finding a compatible mate.

More specifically, it is theorized by some that the hair exists for the purpose of getting soaked in potent mate-attracting pheromones. This initially odorless secretion turns into a musky smell after various microbes have their way with it; a potential mate picks up the scent and their body uses it as an indicator that you are ready to make the beast with two backs, or whatever the kids are calling it these days.

Further, whether consciously detected or not, each individual gives off a slightly different scent thanks to something known as the Major Histocompatibility Complex (MHC).  Studies, such as one having women smell the armpits of t-shirts previously worn by various men who in turn wore no deodorant or the like, have shown that people with dissimilar MHC feel more attracted to each other (and, in fact often become aroused when catching a whiff of such a person). While the research is not yet wholly conclusive, there is even some evidence that when these two with such differing MHC make a baby, they can expect a lower than average rate of miscarriage. It is also thought that greater genetic diversity results in offspring being less susceptible to disease, both suggesting an evolutionary benefit to heading what your nose is telling your brain about a person based on apocrine secretions.

Thus, the theory goes that because the hair naturally wicks these secretions away from the skin, it allows for better ventilation and a more prominent smell than you’d achieve without it.

If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (iTunes, Spotify, Google Play Music, Feed), as well as:

Bonus Facts:

  • Shaving one’s pubic region is nothing new in history, from the Ancient Egyptians to modern day times the trend has come and gone and then come again.  For instance, in the 15th century it was commonplace for women particularly to shave pubic hair for hygienic reasons, particularly as a defense against lice. Now imagine doing that with little more than a really sharp knife…
  • While the practice of shaving one’s private bits has been around for ages, the 19th century British took it to another level.  It was common at this time to cut off some of your pubic hair and give it to a lover as a gift.  Men would even affix this hair to their hats. When not displaying it in such ways, keeping a collection of it from one’s various lovers was a thing.  For instance, King George IV kept his collection of women’s pubes from his various mistresses in a snuff box.  St. Andrews University in Scotland currently possess this snuffbox filled with pubic hair.
  • There are more microbial cells on and in you than there are cells of you… a lot more. In your gut alone, you have about 10 times more microbial cells than your whole body has human cells. Think about it.
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  • The cilia argument for female pubic hair doesn’t really stand up too well. cilia in the bronchial tubes actively direct contaminant upward to be expelled, pubic hair just sits there. You also touch on why public hair would be undesirable in both men and women, lice and other nasty things find hairy regions of humans and other animals as lovely homes and playgrounds.

    • Daven Hiskey

      @RCCJr: Yep, we agree completely. We just included it as it is a commonly touted explanation and really every explanation here is just a guess by researchers. We thought the last one concerning the smell made the most sense and had the most evidence backing it up, though still not conclusively proven by any means.

  • As a man, I do not profess to understand certain things of the female kind, but I think the more important question is not why do we have such hair, but why do women want to remove it?

    • Because men ask them to because they saw it in porn.

    • It started during the Pin-up Girls age of history. They were clean-shaven, so other women wanted to start doing it, and it’s been like that ever since. Personally I stopped. I got tired of the broken, bleeding, chafed skin. And tired of the itching a day later as the hair started growing back. Women shouldn’t be hairless to be beautiful. There’s actually a foot condition I was reading about and its sign is losing hair around your calves. In many cases losing hair is a sign of being unwell. It’s why you lose hair during cancer treatment. Hard to know if something may be wrong with your body if you keep shaving off the hair..

  • I believe the question we need to ask is why does hair grow just about anywhere on ones body yet, it disappears off of many men heads”?

    • Because in the animal kingdom losing hair or fur is a sign of weakness, the body stops fueling the growth of hair follicles as you get older. And we are animals.

      • The answer relies on the climate of the male. Which can be altered in a various amount of ways,
        1: Growing a beard on the face
        2: In a hot or cold area
        3: Drastic stress changes

        You say animals lose hair when they grow older, yet you can look at any other animal in the animal kingdom when they are in their elder years and they retain almost all of their hair or keratin structures and never bald. Its about maintaining core body temperature.

        i.e If a man in a temperate forest region grows a beard, the body will be hotter than normal. So in order to maintain that 98.6F temperature, they have to lose hair first. And since the hair on the head is denser, they lose that first.

        Or if a man lives in the arctic and has few hairs. The first thing that will happen is hair on the head, feet, and legs — As those are the major spots for heat loss. The next step is the face, and body hair.

        Pubic hair exists mainly as a barrier behind friction, as humans up until now just started wearing clothing that cut deep into the pits (T-shirts and underwear) that stop friction for us. So shaving the hair completely may leave exposed cuts in the skin, but TRIMMING the hair may help to keep the groin cooler and much more comfortable as the clothes in modern day Earth actually cut most of the friction for us. Women are different species entirely than men when it comes to hair. Women were never the hunters or gatherers in human society up until now. So it would be natural for you to lose hairs more from stress than a man. But if you get to that point where stress causes hair loss you need to evaluate your life and ask yourself “What stresses can I put away and help myself?”

        • True point about the hair as you age. But I have to disagree with you on the idea that women were never hunters or the gatherers. In some native American tribes and probably in some African or aboriginal tribes still today, some women actually do hunt with the men. It depends on the tribes and what their individual set of rules are.

      • Dorthea Freeman

        mammals not animals

  • One wonders if King George IV’s collection has names to go with it.

  • The armpits and the genitals contain the most pheromones of the body, thus the hair is present to protect and house the scent. (Whether to attract mates or keep it in check) Armpit and pubic hair also help regulate body temperature.. Keeping one’s body temp warmer when we are cold and cooler (by repelling sweat) when hot. Scrotal hair aides testicular temp as well.

  • You have to look at human evolution. The testicals need to be considerable cooler 98.6* in order for semen to thrive. This is the reason they drop around puberty. So yes the hair protects the important bit, the penis. Then you’d ask your self about circumcision. Well before we domesticated ourselves as some may put it, before clothing the body, that extra skin was nesseccary because while cold the penis needed to shrivel in the more the better/more protected. So that excess skin was need to aid in erection size for mating. The white man black man natural inequality debat solved. Lol. That really is why though because after the great continental divide those that stayed in the mother land remained in heat and sun and those in colder regions had to cover there bodies more. This also explains why us white folk are melanin deficient from lack of vitamin D the sun provides. So back to the hair. Our bodies where covered in hair and it will take the more important hair longer to evolve away. This is easily seen also. I don’t care how straight the hair on your head is your pubes are considerably more coarse and darker. Coarse hair insulates better. The armpit in those days would have been a vulnerable body part for vascularity and sweet gland reasons. But hey I could be wrong and I’m sure I’m at least partly inaccurate. Good topic

    • Jessie – the foreskin was not designed to “shrivel in” and keep the penis warm during paleo times. The foreskin protects the penis from abrasions, infections, and it also lubricates and promotes a self cleaning organ because intact men produce smegma much like women. The penis loses all those benefits when its foreskin is circumcised. I don’t buy that it helped “keep the penis warm” because research has proven the foreskin helps in balancing a comfortable temperature for man’s genitals. That whole “sweaty balls” thing? Is much less likely to happen on a day to day basis, to an intact man than a circumcised one.

  • So, what about all of that hair on my back? Any working theories on that mystery yet?

  • Sex with two shaved partners is considerably noisier in various ways (smacking and, in many positions, “flatulent” sounds from skin-skin). You can imagine that noisy sex in various historical situations (wild animals nearby, one-room huts shared with extended family) is, on the average, less successful sex. There doesn’t need to be a connection between armpits and pubic areas, but hairy pubic areas are very good silencers which make for a more profitable union.

    • Why do you thing sex in one-room hut was a problem in pre-christianity era? (= 2k years are such a short time in case of evolution)

      • Pre- or post-christianity is irrelevant. Both pre- and post-christianity, the lower classes tended to live in much smaller houses, with everyone sharing the “bed” room (if they had a room exclusively for beds). In many places the main (and often only) room was the “living” room during the day and the “bed” room in the night. Most activities took place outdoors in the warmer months, and during the colder months a single room stayed warmer than trying to warm multiple rooms. Especially since in the colder months you were cooking inside, rather than outside like you would do in the summer.

        This is true both pre and post christianity. Pre-christian Celts lived in single room houses. Post-Roman christianized Celts went back to living in single room houses after hypocaust technology was lost. Early Anglo-Saxons lived in single room homes. Later christianized Anglo-Saxons still lived in single room homes.

        Early colonizers to the Americas lived in single room homes. Those who pushed westward later all lived in single room homes. The upper classes would eventually build multi-room homes, which middle class people copied – and in modern days we’ve all gotten used to multi-room homes and efficient heating.

        But for the most part, historically the general population could only afford single or two-room homes. And that’s how most children learned the “facts of life” – by listening to their parents in the dead of night. And farm animals.

        Though I don’t see where Brian said anything about christianity one way or another…

  • this article was hilarious in the way it was written, found it very funny and I thank you

  • Well personaly when I go down on a women ,Id rather not have a mouth full of hair .

  • Males absolutely DO have protection. Americans keep cutting it off 🙁

  • I don’t know how you guys can say men were born without protection for their urethra. It’s called foreskin or the prepuce and all boys are born with it. It unfortunately gets removed around the second day of birth due to incorrect stigma and outdated research. But the foreskin actually protects the urethra from bacteria and UTIs. Also, the placement of pubic hair on men does actually meet up with the pubic hair on a woman if the man is left intact. A man’s position during intercourse if he’s intact is different than a man’s position during intercourse if he’s circumcised. Look it up.

    • Men are sometimes born with a shorter foreskin,
      leaving the tip of their genitalia exposed,
      However all men are born with pubic hair.
      Also, during intercourse or arousement the foreskin will be pulled back which again will leave the penis exposed.
      Most men get what is called a “morningwood” almost every day especially during puberty
      This plus the dramatically increased erected state due to side effects from sleeping pills (melatonine) and Ritalin
      (methylfenidate), due to increased prescription of Attention Deficit Hyper Activity Disorder can make an erected state last for up to 8 hours, Since the average person is only awake for around about 12/18 hours a day if this person has prolonged sexual intercourse he will pretty much be unprotected for the whole day.
      Age: 16
      Sources: Research on ADHD, Being an ADHD patient, Struggling with the same problems, Basic Biology, Math.

      • All men are born with pubic hair yes. And during intercourse with an intact man the glans will actually be pulled back inside the foreskin during the out stroke. It’s why intact men typically “last longer” than circumcised men, because when the glans are pulled back inside the foreskin, it provides a brief rest from stimulation. Are you trying to argue that an intact penis still has its glans exposed to the elements the majority of the day? That is inaccurate. Most intact penises, even when erect, do not always retract its foreskin, that is entirely up to the man. Also some men are never able to retract any amount of their foreskin, ever. The rough guidelines to natural retraction are between 10-18 years of age. Sometimes never. So the glans actually spend the majority of every day within its foreskin, not outside of it.

        • A man’s urethra is protected by a thin layer of mucus in the inside. However that only protects from minor invaders such as vaginal fluid, minor dust, most bacteria.

      • All men are born with pubic hair?
        Gotta say, it took me more than a decade to get mine.

      • My foreskin doesn’t completely pull back when I’m errect. I still think what Jeniffer was saying is quite plauaible. Is it not possible that shorter foreskin is a recent evolutionary trait, and that foreskin initially served as protection for the urethra?

      • Don’t ever insult science again with this stupid shit.

  • If any girl likes sniffing body odor and finds it um attractive. That girl is a nutcase! Even the flintstones will find that gross!

  • Joseph E. Bowker

    I totally concur with the Wicking Virtue of Pubes. In Europe where less deodorant and less shaving of Pubes exist, the air was full of the desire to and attraction of a young nearby lady. Woman didn’t have to say, “Hey guy, wanna….., their pubic deodorant free bodies did it and you knew it. I learned to love it, although older working ladies on the way home put off a less friendly aroma.

  • Maybe the pubic hair protects against friction from clothing or from skin-on-skin contact? I don’t have any hair in the “crease” between the genitals and the leg, and I always get irritated skin from friction and sweat during the summer, or simply from having clothing rub it.

  • I couldn’t even finish this article because of this:
    “It seems Mother Nature did a great job of providing women with perfectly placed pubic hair to keep dirt from entering the vagina, but the guys have no such protection around the urethra.”

    Yes, YES, they do. It’s called FORESKIN, and people cut it off! A circumcised penis should NEVER be projected as “the norm.” It is not “normal” to mutilate the genitals of newborns. It has been normalized by culture in the United States, but violating the bodily autonomy of a non-consenting person for no good medical reason should be illegal.