Stuff You Should Know - Why do humans have body hair?

Episode Date: May 5, 2009

Humans aren't truly naked apes, but other primates put us to shame when it comes to body hair. Why? Tune in to hear Josh and Chuckle discuss the theories and hypotheses behind human hair growth and distribution. Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

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Buffalo Park and Zoo, and sports and literary attractions too. Expand your sense of wonder today at visitmississipi.org slash family fun. Mississippi, Wanderers Welcome. Brought to you by the reinvented 2012 Camry. It's ready, are you? Welcome to Stuff You Should Know from HowStuffWorks.com. Hey and welcome to the podcast. I'm Josh Clark. Chuck Bryant, how you doing man? I am well. That sounded very unsure. Yeah, I'm feeling the same way. Chuck and I are recording on a Monday. Jerry's forcing us to. Usually we record on Fridays. It's the last thing we do in the week which is why we're so chipper and up and drunk and you know this is a shift. It's different. Yeah, it's like a funeral. It's hard to on our bus. Plus it's kind of cloudy out

in the weather. I know. It affects me. I have a sad seasonal affective disorder. Do you really? Yeah, a little bit. Like diagnosed? No, no. Self-diagnosed? Yeah, yeah. Are you also self-medicating? Uh, no. Okay. I'm not into that. Good for you. Good for you, Chuck. All right, well I have a question for you. Far away. Did you ever, when you were a kid, did you have one of those little plastic shavers, little razors? Yes. Did you? Did you use it or did you just leave it around? Yeah, I remember getting into my dad's shave cream and playing around like I had facial hair. Me too. Right. And now we do have facial hair. I know. It's kind of like when I was a kid, I, when I was like seven, all I wanted to do was mow the lawn. Right. More than anything else. Oh,

yeah. And then come eight, I actually got to mow the lawn the first three times were heaven. Right. Then after that, I was like, you are such a chump. Yeah. Same thing with shaving. It was, it was like really exciting. And now it's, things just get kind of mundane after you do a number of times, huh? Yeah. I was pretty late to the, uh, a late bloomer to the facial hair too. So later on in high school, like my friend, uh, Jim that you've met. Yes. He, uh, is of Arabic descent and Jim literally had a mustache when he was like the eighth grade. Yeah. It was one of the thin ones. And he was, he's a drummer and a band. And so he had the little, like the mullet and the mustache. Yep. I knew it. I knew a kid like that too. Uh, his name was Ron. He, uh, was a Polish descent

and he actually, his voice was deep in the third grade and his stash started coming around a little, a little after that. I developed a little later. I'm still developing. Oh yeah. Yeah. Your voice is still changing. And it is the very nice Chuck sexy. Um, have you ever wondered though why, how about this first segment? Have you ever wondered, Chuck, why humans even have body hair? I hadn't until I read this article and then it kind of occurred to me. Yeah. That's kind of weird. Why do we have hair? Actually, this, this isn't the, this isn't the first time I've thought of this. Really? Yeah. Did you think that when you were a little kid? No, anthropology student. Oh, okay. Yeah. I didn't, I wouldn't down with anthropology.

I remember how we were just talking about, um, uh, shaving the face. Did you know that you were, I will probably spend about a month out of our lives, uh, shaving average less than that. But yeah, I'm below average. I shaved once a week. I shaved once a week too. God, we are made for each other. I know. Wow. All right. Well, let's get to this. All right. Yes. Why, why why does your hair grow the hair on your head, uh, grow longer than the hair on your arms? Chuck Bryant. Well, I, before we go there, Josh, we need to understand a little bit about hair. Can we go there? Uh, what happens is when you're talking hair growth, you have cells inside the hair follicles. They divide and they multiply. Right. And then space fills up

inside the follicle and it pushes older cells out. Right. Because hair is actually just like the protein keratin and dead cells. Yep. Right. That have hardened. Right. Yeah. That sounds kind of gnarly when you put it like that. Did you know like something like 98% of all dust is dead skin cells? Oh, really? Uh-huh. It's like, uh, bed bugs, not to get off on another tangent, but all that stuff grosses me out. Sure. Never bring a black light into a hotel room. That's all I have to say. Right. So, uh, as space fills up, uh, it pushes the older cells out like I was saying, and those cells harden and exit the follicle and forms a hair shaft. Right. Which you said is mostly dead tissue and keratin. Correct. Yes. So that's basically what's going on,

but it happens in spurts. It rests and it, uh, active in resting phases. So the, the active phase, the growth phase is called the antigen phase. Yes, sir. And then there's the telegen phase and those are resting phases. And as strangely enough, these, the, your different parts of your body go through different phases at different times. Right. Which is what you're talking about with the arm and the head. Right. So your arm hair has a much longer telegen or resting phases than your hair head or your head hair. Head hair. Yes. Which I usually just call hair, which is why this is going to be a really confusing podcast. I know because there's different types of hair on different parts of your body. So yeah, let's, let's caveat

that right now. If we just say hair, we're talking about the head, the scalp. Okay. Okay. Sure. Everything else is facial hair, arm hair, you know, there's a qualifier, but let's go ahead and get the different types of hair out of the way. Let's do it. What you have in the womb, um, are little tiny hairs called, uh, lanugo. That's, that's how I pronounced it too. Good. Uh, then after you're born, uh, babies grow vellus, which is fine unpigmented hair. It's like peach fuzz. Yeah. That's what I got. Yeah. Little baby's heads are all soft. It's just so cute there. Um, and then you hit puberty, most of us. And the vellus hairs give way to terminal hairs and they're a little more coarse.

And that's what you find underneath your armpits and around your genital area or on my back, on your shoulders. Sure. You've seen that hairy back. Holy cow. Really? Yeah. I've never seen you with your shirt off. I'm like a class four or Robin Williams level of Harry. Wow. I'm not quite there. It's up there. Yeah. Sure. Yeah. I'm not that bad. I have the creepers that come around on the collar, but, uh, Emily, um, waxes me from time to time. Does she? Yeah. My brother-in-law is shaved by my sister down to where the, uh, collar of his undershirt comes. Uh-huh. And if you ever see him with his, his shirt off, it's like hair, no hair. It's really hilarious. It's like the red neck tan. Kind of. Yeah. That's nice. So then back to the hair that we all think about, the hair on

the scalp, uh, the thicker hair, eyebrows, eyelashes. That's also terminal hair, which is the same as, um, what a lot of people call pubic hair. Yes. It's actually the same type of hair. You might not think so, but it is. It's terminal. Okay. So, and then, uh, the different kind of hair, this is distribution, not the type of hair, uh, is androgenic. Yes. And that's like your facial hair, your chest hair, your arm hair. And it's usually stimulated by, um, the hormone testosterone. Right. So there you have it. And then you add all that up together, Josh, and you get about five million individual hairs for an average adult. Which is strange because that's about the same density as a chimpanzee. Did you know that? I did. And this is where it gets a little more interesting.

I'll get all the science stuff. Thank God. Get all those terms out of the way. Um, now we're talking about chimps. And this is something that I did not know until I read this. Uh, we actually don't have, uh, fewer hairs than a chimpanzee. It's the size of the hair, actually. Yeah. They're shorter and less coarse. Yeah. So we have about the same number of hair follicles, or at least the same density of them as a chimp. Yeah. I bet no one would answer that unless they knew. No, but we could. Well, sure. We should totally go to Trivdenite. And now the dozens of people who listened to our podcast could know that, too. Exactly. Um, but we also, uh, on the chimps, we also share the same, uh, hairless parts, which is, uh, lips, palms, and soles of the feet. No

hair. I have hair on my palms. Well, I'm not going to go there. Okay. In 1968, five black girls dressed in oversized military fatigues were picked up by the police in Montgomery, Alabama. I was tired and just didn't want to take it anymore. The girls had run away from a reform school called the Alabama Industrial School for Negro Children, and they were determined to tell someone about the abuse they'd suffered there. Picture the worst environment for children that you possibly can. I believe Mt. Megs was patterned after slavery. I didn't understand why I had to go through what I was going through and for what. I'm writer and reporter, Josie Duffy Rice. And in a new podcast, I investigate how this reform school went from being a safe haven for

black kids to a nightmare and how those five black girls changed everything. All that on unreformed. Listen to unreformed on the I Heart Radio app, Apple podcasts, or wherever you get your podcasts. In 1980, cocaine was captivating and corrupting Miami. Miami had become the murder capital of the United States. They were making millions of dollars. I would categorize it as the Wild Wild West. Unleashing a wave of violence. My God, talk about walking into the devil's den. The car sales, they just killed everybody that was home. They started pulling out pictures of Clay Williams' body taken out in the Everglades. A world orbiting around a mysterious man with a controversial claim. This drug pilot by the name of Lamar Chester.

He never ran anything but grass until I turned over that load of coke to him on the island. Chester would claim he did it all for this CIA. Pulling many into a sprawling federal investigation. So Clay wasn't the only person who was murdered? Oh no, not by a long shot. I'm Lauren Bright Pacheco. Join me for Murder in Miami. Listen to Murder in Miami on the I Heart Radio app, Apple podcasts, or wherever you get your podcasts. Hello. So Josh, do we need to talk about some theories? Yeah, I like this. This is why I've thought about this before, because we were taught this kind of stuff in anthropology, my anthropology class. You're the whiz. Okay, so my favorite theory, this is the one that makes the most sense to me, is that we started losing our hair when we

became bipeds. If you look at most primates, they have a tendency to walk on their knuckles as well as their feet. That's how they move most quickly, which would require you have a lot of hair on your back, because then that whole area is exposed to the sun. Exactly. The whole point of hair, well actually there's two points, right? One is to regulate body heat, to keep your body warm, sure, and the other is to protect from UV radiation from the sun. Okay, pretty cool. So once we started walking upright, we needed hair on our head, some on our shoulders maybe, a little on our back, some on the chest, and then everything else is kind of sexual, right? Absolutely. I think about one-third of our bodies are exposed to sunlight once we started walking upright. Right,

so that's the one that makes most sense to me, but that's pretty far from the the only theories. What else you got? Well, there's another one I thought was kind of cool, that one theory was that early man was a water-dwelling ape. So since they were in the water, you know, you don't need hair in the water, you don't see a lot of hairy fish. No, nor hippopotamide or rhinos or anything like that. Elephants, yes. It's been a lot of time. And they're all mammals, they have very sparse hair growth, right, because they're in the water a lot. Absolutely, so I kind of like that one. Yeah, that one makes sense. The other one that makes sense to me is that about 1.7 million years ago, we went from a basically a forest-dwelling species to kind of moving more out in the open, right?

Mm-hmm. And since we're in the forest, we would not be exposed to the sun as much, and it'd be cooler because we're out of the sun, so we would need more hair to keep our body temperatures higher, right? Right. Once we move out into the open savanna, we don't need the hair anymore. Why'd we move out there? Was that when we started developing weapons and stuff? Probably food, we always move for food. Okay. That's usually food when, is the basis of migration. That's where all the good meat was. Yeah. Okay, so the thing is, is if we lose our hair and we're now exposed to the sun chuck, we still need to protect ourselves from UV rays, but we need to use a method that doesn't keep us hot, right? Sure. Enter skin pigment. Okay, this is news to me.

Okay, so actually, there was this researcher in 2000, Dr. Rosalind Harding at Oxford, and she went back and traced the evolution of the MC1R gene. This is the gene that produces either a dark pigment or a lighter reddish pigment depending on where we live in our exposure to the sun. The closer you live to the equator, the darker pigmented you're going to be. Okay. Because it protects skin from sun cancer, skin cancer, that kind of thing, right? Sun cancer, I like that. Sun cancer, it's the worst kind. So Professor Harding or Dr. Harding, I'm sorry, traced the mutations on this gene as they're found in African populations, which strangely enough, there are no mutations or I'm sorry, there's no variation among Africans of

this gene. Okay. And if you go and you look at Asians, you look at people of Nordic descent, Native Americans, we all have the MC1R gene, but there's variations on it. In Africans, it doesn't matter where you go on the African continent, you find the same exact gene with the same exact mutations. And that's the birthplace of humanity. Yes. Many believe. Sure. So, which I was also surprised, we apparently only exited Africa within the last like 50,000 years. Really? I thought it was way further back than that. But I read an article in the New York Times that said different. Wow. And they know. Sure. So anyway, Dr. Harding traced the evolution of this gene through mutations back to about the last time it swept through the African population. And she

found that that was about 1.2 million years ago, right? Now, the point of this is that when this gene, when this mutation would have swept through, thus darkening everyone's pigment, we would have needed it then. So for at least the last 1.2 million years, Dr. Harding posits that we've been hairless. Gotcha. Pretty cool, huh? Yeah. Yeah. That all makes sense. It does. I love it when it comes together like this. It all makes sense. Sure. Yeah. But I also like biological and anthropological abnormalities that don't add up. I know you do. Let's hear about it. Well, now I don't have. Well, are you talking about the hairy guys? The very hairy guys. Yeah. That actually wouldn't have set up, but I'll take it. We are talking about hypertrichosis.

Okay. Which some people might have seen. They're called the wolf people. I don't know if they call themselves that. Well, they may not. But that's what they're called in the research I've done. All right. Victor Larry and Gabriel Danny Ramos Gomez are in a family of 19 that span five generations. Wait, wait, what? That's their name. No, no, no. A family of what? A family of 19. Holy cow. Yeah, exactly. Well, that's 19 over five generations. Well, there is bound to be some genetic mutations in a family of 19. Absolutely. So they all suffer from that rare condition. It's called congenital generalized hypertrichosis in their case. And basically what that means is a lot of body hair. We're talking 98% of their body is coming

here. Yeah. I was looking at that picture that you have and you can basically see their eyes. Yeah. And around the lips. Oh, yes. And around the lips. They look kind of like they're wearing hairy ski masks. Yeah. Yeah. And is that they're one of their little siblings? No, it says it's one of their fans. Oh, okay. They're taking a picture with one of their fans. Very cool. And there's also a man in China named Yu Xinhuan and his claimed fame. He has the same thing. He's called the hairiest man in China and hair covers 96% of his body and he is trying to become a singer apparently and make it big as a singer, which I thought was pretty cool. Yeah. I think the, uh, the Gomez brothers have him beat big time. Well, by 2%. Yeah, not much. And, um, and

Yu was actually made his entertainment debut at the age of six in a movie called a hairy child's adventure. So early on he was, he felt like he was exploited somewhat and I'm sure he was ashamed, but he's learned to live with it. And now, um, kind of embraces it, which is kind of cool. A hairy child's adventure. I'm looking that one up. Yeah. I'll bet it's riveting. So that is hyper trichosis in a nutshell. Um, you know, there's a lot more, maybe we should do a full podcast on this is pretty interesting. Yeah. But they, you know, shaving, plucking, uh, electrolysis and laser removal, they're different cosmetic things you can do to, uh, to help that out. You know, um, I also did a tab bit of research on that and, um, you can, there's an acquired version. There's

genetic version. Right. There's an acquired version and through malnutrition, you can, you can develop this. Well, so your starvation diet, you better watch out buddy. That explains the hair on the back. Yeah. Is it sprouting more and more lately? Yeah, it is. And it's getting kind of billy goat-esque. Ooh. Yeah. I had a pet goat. Did you know that? I did not. That's good stuff. How is its hair? Uh, growth pattern? Yeah, of course. Goats are really great pets, actually. Yeah. Very affectionate. Yeah, they are. They're, they're, um, they can cause some serious allergies though. Oh, really? Sure. Yeah. I didn't know that. Yeah, you do now. So here's to you, Nester, my goat. Hey, Nester. Thanks for listening. Uh, you want to do one last thing? Sure. Okay. So, uh,

what's the deal with growing hair and armpit hair? I mean, these places aren't exposed to the sun any longer. Right. If they are, it's at like camp sunshine, nudist resort. Right. Uh, you tell me, camp sunshine is actually a camp for, uh, kids with cancer. So I doubt that's not a nudist resort. Oh yeah. Well, uh, there's another word that you're thinking of the, uh, that one. Camp sunburst. No, it's, it's, it's camp sunshine in upstate New York. Okay. Yeah. It's, it's funded by the same people strangely enough. Yeah, it's awesome. In 1968, five black girls dressed in oversized military fatigues were picked up by the police in Montgomery, Alabama. I was tired and just didn't want to take it anymore. The girls had run away from a reform school called the Alabama

Industrial School for Negro children, and they were determined to tell someone about the abuse they'd suffered there. Picture the worst environment for children that you possibly can. I believe Mount Mages was patterned after slavery. I didn't understand why I had to go through what I was going through and for what. I'm writer and reporter, Josie Duffy Rice. And in a new podcast, I investigate how this reform school went from being a safe haven for black kids to a nightmare, and how those five black girls changed everything. All that on unreformed. Listen to unreformed on the iHeart Radio app, Apple podcasts, or wherever you get your podcasts. In 1980, cocaine was captivating and corrupting Miami. Miami had become the murder capital of

the United States. They were making millions of dollars. I would categorize it as the Wild Wild West. Unleashing a wave of violence. My God, talking about walking into the devil's den. The car kills. They just killed everybody that was home. They start pulling out pictures of Clay Williams' body taken out in the Everglades. A world orbiting around a mysterious man with a controversial claim. This drug pilot by the name of Lamar Chester. He never ran anything but grass until I turned over that load of coke to him on the island. Chester would claim he did it all for the CIA. Pulling many into a sprawling federal investigation. So, Clay wasn't the only person who was murdered? Oh, no, not by a long shot. I'm Lauren Bright Pacheco. Join me for

Murder in Miami. Listen to Murder in Miami on the iHeart Radio app, Apple podcasts, or wherever you get your podcasts. No, the theory, no, I guess hypothesis. Right, not a theory yet. Behind why we have growing hair and armpit hair is because these places are where we emit the most. Yes, do you see where I'm demonstrating? Right here, Chuck. Down here. These are where we produce the most pheromones. And the hypothesis is that the hair acts as kind of like an amplifier for these pheromones. Does it traps in the smells? Mine does. Interesting. Yeah. What a grisly topic. Kristen Conger wrote this, right? Yeah. Way to go, Conger. If you want to read it, you can type in why do humans have body hair

in the handy search part, howstuffworks.com. Okay, so we did that. All right, so that's why do humans have body hair, right, Chuck? Because we need it. Yeah, I guess. Although, you know, if we ever make it back into the water, prepare to go bald. Right. And it's funny hair, human head hair is become one of the more distinct features that, you know, people have hairdos, and it's not, it's a very cosmetic, cosmetic thing. Yeah. You know, it's not just, I mean, it's there for our, to protect our head. But it's also to look cool. Yeah, that's what I'm trying to say. Yeah. Get a mohawk, maybe? Sure. Okay, well, let's, let's plug something, Chuck. You. You plug. Oh, okay, I'll plug. So let's plug the blogs. Okay. Chuck and I have a blog called

Stuff You Should Know, appropriately enough. And we just post about all sorts of cool stuff. Chuck does a podcast goodness roundup every Friday too. And yeah, we post each once a day, every day during the week. And you can find it on the right rail on the homepage of howstuffworks.com. Yes. And there's our blog plug. Perfect. Which means? It's your mail time. Josh, today, I'm just going to call this the Great Australian Toad Wart Correction Task. Okay. We missed quite a few things on this one. I'm not ashamed to admit that happens occasionally and it happened this time. So here we go with corrections for the Toads Calls Warts. I see that part of it's been redacted.

All right, because someone was wrong, they wrote in and said that Toads were not in Perth. But I went back and listened and you said that they were heading toward Perth. And I sent the guy a link to an article that verified that they are indeed heading toward Perth and are going to make it there. So beyond that one, Josh, at one point you said there are no predators that have figured out how to eat the cane toad because of the toxins on its back. And apparently, an Australian woman wrote in and said that crows have learned how to flip them over and attack the belly of the cane toad. Oh, but that's an unpleasant sensation. So thank you for that. We don't have names. I apologize about that, folks. I was short on time.

We also mispronounced HPV, which is... I know. Go ahead and say the real word. Human Papioma Virus. Yeah. Right? Yep. And we said Pavlova Virus. I know. And that was my fault. As we all know, Pavlova is a dessert and it was a famous ballet dancer. And you and I are both into eating dessert and watching ballet. So we probably just... At the same time, too. So that... Yeah, I apologize about the mispronunciation. Josh, he said that there are alligators. He said it kind of in a flip way in Australia. Oh, no. Not true. It's crocodiles. Wow. Were we drunk during that one? No, we weren't. But the list goes on. I mispronounced salicylic acid.

Apologize about that. And that is the last correction, but we should mention a couple of folks wrote in and talked about ways to get rid of warts that we did not know. Okay, let's hear them. And duct tape was the most well regarded. I mean, a lot of people said, if you put duct tape on it and leave it for a little while, it will get rid of your wart. How long is the little while? Did you get an impression? No, I didn't. Until the wart goes away? Yeah, I would guess so. Okay. And then Chris from LA, he calls it Lower Alabama, which I always think is funny. He said breast milk. And I haven't heard that one. So that is unverified, but that's what

Chris says. Chris just may have a think. Maybe so. Yeah. So, well, yeah, thank you for all those corrections. Do you want to get the Eau Claire thing out of the way now? I'll go ahead. So it's not Eau Claire Wisconsin. It's Eau Claire Wisconsin. In Wisconsin, folks wrote in and said, no, no, no. Yeah. Actually, yeah, I guess we should say it's Eau Claire Wisconsin. Wisconsin. Yeah. So, yeah, thanks for everybody who wrote in to correct us. Whether you were correct or not, you know, if you mentioned Perth, that's okay. Right. The Aussies loved it, though. They love hearing podcasts about themselves. We got a lot of good feedback. Right. We'll have to do that a little more often.

Yeah. Okay. So if you want to send us any words of encouragement, any words of derision, anything at all, you can shoot an email to stuffpodcast at howstuffworks.com. For more on this and thousands of other topics, visit howstuffworks.com. Brought to you by the reinvented 2012 Camry. It's ready. Are you? The war on drugs is the excuse our government uses to get away with absolutely insane stuff. Stuff that'll piss you off. Cops. Are they just like looting? Are they just like pillaging? They just have way better names for what they call like what we would call a jack move or being robbed. They call civil acid.

Be sure to listen to the war on drugs on the iHeart radio app, Apple podcast or wherever you get your podcast. On the new podcast, The Turning Room of Mirrors, we look beneath the delicate veneer of American ballet and the culture formed by its most influential figure, George Balanchine. He used to say, what are you looking at, dear? You can't see you, only I can see you. What you're doing is larger than yourself, almost like a religion. Like he was a god. Listen to The Turning Room of Mirrors on the iHeart radio app, Apple podcasts or wherever you get your podcasts.