Mind Body Evolution Podcast

Human Sex

In this episode Dr. Josh Stout discusses how human sex is unique in the animal kingdom.

Dr. Josh Stout, PhD

Mar 9, 2024 — 29 min read

Human sex is unique in the animal kingdom

Human sex is unique in the animal kingdom.

Please scroll down for links below the transcript. This is lightly edited AI generated transcript and there may be errors.

Eric 0:08

Thursday, March 7th. And this is episode two of season 11 of Mind Body Evolution. Hi, Josh.

Dr. Josh Stout 0:15

Hi, Eric. So I, I wanted to do something back into my normal evolution human consciousness discussion and leave the cosmology behind for a little bit.

Eric 0:27

And it's funny because I thought you were saying that the cosmology had you completely obsessed. You couldn't think about anything else.

Dr. Josh Stout 0:33

Well, that was a time that's that's that's what being ADHD is like. You you find a topic, you get really deep into it, then you move on to the next thing again. Okay, so this this is why I love a podcast. I need new topics all the time and I dive into them all the time.

Eric 0:46

And they're always fun. Keep going.

Dr. Josh Stout 0:48

Thank you. Well, so I wanted to talk about human sex this week. Not as you know, a how to guide, but.

Eric 0:57

Yeah, it's weird because we don't normally talk about it as humans. Sex.

Dr. Josh Stout 1:00

Well, indeed. And humans have some really unusual sex within the animal kingdom. I we have giant brains, we're bipeds, we are tool users and we can throw better than anything else. These are the things that make us human and are our sexual characteristics. And behaviors are also equally unique. We often think about sex as somewhat animalistic and not human in some way. That is that is very, very wrong. Our sex is not like that of animals. And within animals, there's so much variety that you can't even pin down what that would even mean on. And I wanted to start out again sort of emphasizing that when I talk about these things within biology, I tend to set up binaries because that's how I can talk about it. But that even within the, you know, purely biological world, these things are essentially constructs that we're we're describing within the species with a lot of variability.

Eric 2:06

And I think you've we've, we've touched on this, we've.

Dr. Josh Stout 2:08

Touched on a different a couple of different ways. But I wanted to talk I begin on sort of, you know, what is sex, what is what's it for, how is it happening? So sex is a way to combine gametes for genetic variation and it's gametes, gametes, eggs and sperm. So each one has half of the parent's genome and then you mix them together to make a new mix and match. That's half of each pair.

Eric 2:33

And this is in any species.

Dr. Josh Stout 2:35

This is basically any species that has sex. Parthenogenesis aside, I and so it's just evolution, trying to get the gametes together and it doesn't care. So you know an anglerfish the female is huge and the male is an appendage. Other ones, the the, the male is very dominant and the female is, is trying to woo the male. Generally, whoever does more of the work and caretaking gets to be the camouflaged one, the one that does the, you know, sperm donation, which is very low cost, gets to be the flashy one. That's often how things are in the animal kingdom. So you've got the red cardinals with the brown females, etc.. But there's also all sorts of different modes. So there is there's various kinds of more or less monogamy. There's a lot of cheating out there. Most species that mate for life have very high incidences of extra pair mating, as they call it, really, and don't seem to make that big of a deal out of it. But they, they there's a lot of mate guarding usually by males of females during during mating season but it's not always successful and there is not a huge repercussions to it I that that if a female gets away with it she gets away with it. And one of the...

Eric 3:58

And how does a female not get away with it?

Dr. Josh Stout 4:01

The male pounces on them and rips the other male away. So for example, in toads, when toads are mating, they're all calling at once and there's this giant pile of toads and each male is trying to climb on a female and do what's called an plexus, where he grabs her around the throat and pushes away with his back legs. And it's just sort of like a like a rugby scrum fighting for the females and then then it's pure male male competition. Other times it's it's more of a male has to woo the female. And so you have mating calls and displays to, you know, for a male bird to get a female bird, he, he has to do very fancy dances or have beautiful plumage and as a, as a, as a way of attracting her the perfect song of all these things. And that generally indicates that he's he's doing less effort. But even in those cases, you know when I mentioned a cardinal, the male has a lot of parental care. He just doesn't have to make eggs, which are way more expensive than sperm. So there's still more cost for him, but he's going to be there bringing up the kids as well and guarding the territory. So it's very much he's still having to do a lot of work. But I wanted to mention the idea of sneaker males, because they're they're really interesting within the biological kingdom. Often when you have male male competitions, the males are much larger than the females and will not tolerate any other male in the area. But because evolution really doesn't care about doing anything other than getting gametes together, there's other strategies. So smaller males will act like juveniles that are immature, have no male colouring and then sneak up and mate with the females while the male isn't looking. And this is a really common thing among many, many, many, many species.

Eric 5:51

Really? Sounds like you're talking about gorillas or something, but frogs fish.

Dr. Josh Stout 5:58

Really? Yeah. Yeah. Across the board are interesting versions of them. Well, not just acting like a juvenile, but acting like a female. And that way the male welcomes them in. One of the more interesting examples of that is in the the giant cuttlefish, which is, you know, a large, intelligent mollusk so very far from our lineage. And they communicate with colors on their body. So, for example, a male trying to attract a female will have a particular colour, a male being aggressive and trying to chase off another male will have an aggressive color. They actually look aggressive. There'll be bands of color washing over it and, you know, very bright and aggressive. If there's a male and a female on either side of it, it'll have aggressive colors on one side and come love me colours on the other too. The female, the female's communicating with her colors a smaller male will assume the body shape and colors of a female and be welcomed in by the larger male and then mate with the female directly underneath him where he can't see.

Eric 7:03

It's amazing.

Dr. Josh Stout 7:04

Yeah, it's insane. So these are things that are that are that are fully part of, of of, of the biological world where there is there is there is, you know, changes of sexual appearance and behaviors.

Eric 7:21

Are subterfuge.

Dr. Josh Stout 7:22

As as part of a a strategy which then gets passed down genetically.

Eric 7:29

It sounds like so complex strategy that it. Well evolve. I mean it must it's hardwired in it's incredible.

Dr. Josh Stout 7:35

I was just reading about wrasses where as a wrasse matures, it'll actually change sexes.

Eric 7:42

Sorry. As a as a what?

Dr. Josh Stout 7:43

I'm sorry. A kind of fish. A wrasse. It starts with a W.

Eric 7:47

W R A S S. Never heard of this. Okay.

Dr. Josh Stout 7:51

Could be any on the end. I don't know. Sure. Okay. Rats. Anyway, they, they, they're very colorful re fishes and they change sexes partway through their life, some of them. And so they'll go from being a male to a female as fascinating partway through their life. But they're also competing. The males are competing for the females and they will sometimes take on females shape while still being a male. So they can then sneak past the the combative males and mate with the females. And what I was just reading is they don't just change their color, they actually change their brain so that they have female stereotyped behaviours in their brains. So, so these, these, these sex changes are 100% except for the gametes. The gametes are the only thing that stay with a little bit of behavior that allows the male and female to actually get together. So they're fully changing their body and then leaving their gonads where others males are fully changing to female and changing their gonads. So yeah, that's what I meant, that complete flexibility and I'm still using it as a binary male and female, but it is by no means a binary. These are just labels we are placing on the biological world. And so I wanted to make that really, really clear and that I am pro messing with labels, but I'm using these labels, so I just wanted to talk about that as as we're entering it. What do I mean by human sex is, is unique. We have.

Eric 9:20

Yes. What do you mean by human sex is unique.

Dr. Josh Stout 9:23

We have we have we have many of these same traits. We have male male competition. We have display. Interestingly, we've reversed the display. Generally, females are the ones that get to wear the prettier clothes and displaying for males. And you know why? Why would that be in biological systems where you see a, you know, bright, beautiful female bird and a drab brown male, it turns out it's the male that is then actually doing all of the mate guarding, and the female goes and lays eggs and several males nests. And the males all have to take care of them. So, you know, purple gal animals, other other birds like that, it's actually the female that's bright because the male ends up doing all the work. So for a long time, in many, many societies, women have been dependent on men to bring them their resources so they can raise families. And so females have needed to be attracted attractive for men. For this reason. This is interesting because men still are slightly larger than females, implying male male competition, actual physical fighting occasionally. Otherwise there's no reason to be larger. Size implies calories. Calories are a cost. There's a cost to being larger. Bigger people die when there's a famine, so there's a risk to it as well. But it's worth the risk to be a little bit larger because you're more likely to succeed and find a mate because you can beat up some other guy. And sometimes it just comes right down to that. And there are there's evidence that, you know, women are attracted to taller men. So there there is an actual preference there. The females presumably have had to do this since really the beginning of our genus. As soon as we began began to get larger brains, the behaviors of females would have had to have changed as well as their appearance. And so this is what I'm talking about. What I'm saying human sex is is is unique because of changing the normal roles where the the female has to be more attractive than the male. That's that's not a normal way to go. It does happen in the animal world, but this is an unusual version of it. And the reason that is, is because the babies need so many calories for their giant brains and because they're so dependent, they can't they can't move around because to have a giant brain, it has to be, you know, almost a quarter of their body when they're born. And so there's no way they're lifting their heads. You know, a baby can't touch its arms above its head. Yeah. Like its fingers. Like if they held their arms straight up, they had.

Eric 12:13

To go over their head. Yeah.

Dr. Josh Stout 12:14

Yeah. Their head made gigantic. So yeah, you know, that is, that is not a creature that's going to be fending for itself any time soon. So a mother is then tied down, you know, she might want to hunt, she might be able to hunt, but she can't go hunting while nursing an infant and she can't go hunting when she's eight months pregnant. So she absolutely is dependent on calories coming from the male right from the beginning of our species. And it's defined by the way our species is because the the brains couldn't be any bigger at all to get them to get smarter. We actually develop for several months out of the womb in a way that normal animals develop inside insides still inside the womb. So we have several months of of post gestational gestation, essentially, and this requires a lot of calories from the male. So right…

Eric 13:05

Complete dependence.

Dr. Josh Stout 13:06

So right from the beginning, males have have been necessary for the females and a vital portion of it. And so the females are the attractive ones. So before clothing, what were we doing? So females were developing breasts. They were developing a, you know, buttocks and waist that were directly going to advertise their fertility. The fat that goes to breasts, buttocks and waist are a dedicated fat in females. It's the first on and the last off. The only time it goes away is in the last trimester of pregnancy. There are there are hormone enzyme relationships that start dissolving this particular kind of fat, but then it's built back on right away as soon as you're done really with the early nursing. So this is the first fat on the last fat off because it's the one that's most attractive and it's the what, two men and it's the one that evolution cares about the most. And evolution does not care that women care.

Eric 14:06

And you're saying that it's the most attractive to men because it advertises fertility.

Dr. Josh Stout 14:10

It advertises fertility. And so, you know, no other primate has breasts. No other primate has the, you know, the buttocks and waist of of a human female that kind of, you know, very large, voluptuous shape is is is directly related to male attractiveness. And what I was saying that it doesn't care evolution doesn't care about what the female thinks about it - doesn’t care if she makes a choice or not. As long as the man's attracted to her, then she's going to get pregnant. Now, after that, she has to keep the man attracted again. This is building into stereotypes of gender. I'm sorry, but this is this is how the strategies are built in to the way things work.

So she needs to stay attractive to the man.

Eric 14:59

So that the calories keep coming.

Dr. Josh Stout 15:01

So the calories keep coming. And so…

Eric 15:02

And the baby survives.

Dr. Josh Stout 15:04

Other other organisms. You know, even in our lineage, chimpanzees will do all sorts of alignments with different males, sometimes exchanging small amounts of meat for sex later. So this is already in our lineage.

Eric 15:22

Yeah. I think you also I think we've talked about this in the first season.

Dr. Josh Stout 15:24

We did talk about this.

Eric 15:25

Yeah.

Dr. Josh Stout 15:26

But it became more accentuated when we started eating more meat because our environment was producing fewer easy to gather calories. We started turning towards meat to feed our giant brains, which allowed us to make the tools which allowed us to get more meat. All of this required.

Eric 15:43

And then the marrow.

Dr. Josh Stout 15:44

Women being attractive 24/7 essentially. And so in chimpanzees, when they're going into estrus, there's this huge sexual swelling. It's like a pink grapefruit sticking out behind them. And human females do not do that is really hard to look at a human female and know if she's ovulating or not. Right. And that's intentional. So she's always advertising, fertility and attraction, even when it's essentially a lie. Now we do know it's really interesting. The the both hormones and and pheromones are something that is influencing our behavior all the time and influencing our behaviors with each other so we can…

There is a slight preference for an ovulating woman by a man. If you look at hundreds of pictures and rate them, the ones who are ovulating will have a slight increase in the bell curve.

Eric 16:44

Even though we don't know. We know.

Dr. Josh Stout 16:47

Even though we don't know, we know. So generally when you're ovulating, your hair is going to be a little thicker, a little glossier. But the same thing is true in early pregnancy, probably for the same reason you're extra attractive when in early pregnancy. I don't know if those have been put into the, you know, rating things. They sound like, you know, frat boys outside, you know, holding up things.

Eric 17:05

I'm sure these things have been tested. We have to look this up. I this sounds like something that.

Dr. Josh Stout 17:10

But yeah, the the the the the the idea is that we do know a little bit, but it's it's it's minor and it can be done two different ways.

Eric 17:20

I know that. I know many women, including my wife who will look at a woman and be like she's pregnant. And I'm just like, yeah, yeah, of course she's right.

Dr. Josh Stout 17:28

And it's usually the thicker hair and the sort of round her cheeks. It fills in a little bit more. But the the the idea of Sorry, you distracted me. Sorry, the, the idea of, of being able to rate women by their ovulation is something that can be done by both visually and by pheromones. So if you have just pictures, women, men will statistically tend to choose the women who are ovulating. But if you show the same pictures and then have swipes from underarms and have men smelling it while they're looking at the pictures, they'll rate the ones highest that they smelled with the underarm smell from an ovulating woman. So we do know we are animals. We are responding to these things. But it's not it's not very conscious, but it is definitely, you know, part of our of our, you know, dance among each other of sexual attraction and how we're relating.

Eric 18:29

So even though a woman doesn't end up having a giant bulbous red a protrusion, we still there's still an advertisement, even if it's not.

Dr. Josh Stout 18:41

Subtle and it's probably purposely subtle. It's it's, it's, it's based on things that the male would really like to know. So we're probably really good at it. And the female would really like you to not know. And so she's really good at hiding it or pretending to be that way. So, you know, all, all of our cosmetics and.

Eric 19:04

And none of this is ever happening on a conscious level.

Dr. Josh Stout 19:06

None of this is ever happening on a conscious level. All of these things spoof it. Perfumes are based on sex pheromones that we're modifying, you know, from flowers that modified sex pheromones to attract insects, all of these things, you know, the redder cheeks, all of these things are imitating, you know, the the look of of sexual anticipation and and the smells of sexual abuse.

Eric 19:29

You're saying in most of the in most of the animal kingdom, this kind of flamboyance is on the male.

Dr. Josh Stout 19:35

It's absolutely on the male. Yeah. Yeah. And so the female would then, you know, accept or reject. Now, the way we tend to do it, you know, before before Internet dating bars worked a lot like a lack elect as a place that males go to congregate and show off and then the females go and choose the male. That's the best one who example, prairie chickens, etc..

The way bars worked, not that I know from firsthand experience, but this is something that I have read about, is that usually a woman would make the first move so she would look at a guy and then look back and then you know, go back to talking to her friends or whatever. And that was the opening move. And then it was up to the male to come to her. So she was displaying and doing her display, and the male would then come to her and choose her and, you know, can I buy you a drink, that sort of thing. And so that this was this was basically a lekking display. Females going to a place to display and then the males coming to them. And so that that is also sort of, you know, part of the way we we are working in this, I'm sure.

Eric 20:50

I think we're just too old. I think it still happens.

Dr. Josh Stout 20:52

I mean, you know, absolutely. Yeah. But, you know.

Eric 20:54

Internet has definitely affected things, but it still happens.

Dr. Josh Stout 20:57

I'm sure it's it's interesting to think about how how, you know, all of these games are being played in manipulation and and attractiveness and the desire to, you know, pass things on. But it goes it goes beyond just women developing breasts. Men have unique traits within the primates as well. So all the carnivores and all of the primates have a bone in their penis called a vacuum. And I you could imagine how this would be useful. Evolutionarily, erections are a lot easier if you had a bone right through the middle of the penis.

Eric 21:39

Just whenever you want a bone.

Dr. Josh Stout 21:41

Yeah, you're ready to go. And humans do not have one. This is interesting to me because what does this mean? It means.

Eric 21:51

Evolutionarily what does this mean?

Dr. Josh Stout 21:53

What does this mean evolutionarily? It's not necessarily in the guys favor because he might not be ready when the woman is ready. He can't just do it because there's no bone there. So to successfully meet the woman needs to in some way entice the male. So again, it's putting the attractiveness onto the female because if she can't turn him on, that means that's not good genes on her part. She's not going to keep attracting him. Now, I mentioned that the woman has to be attractive at the beginning, obviously, but then she has to keep him attracted. So he sticks around and provides more calories. So I think that men not being able to get erections is actually a evolutionary strategy so that women are being forced essentially to to seduce men. And that is part of the I.

Eric 22:52

Mean, men not walking around with a bone in their penis, making it so that they all.

Dr. Josh Stout 22:56

Just ready to go any time. Yeah. Is is is an evolutionary strategy that that that is not necessarily in the male's genes favor. So it's it's in the favor of the offspring so therefore it's in the favor of the female because if her offspring are benefited then she's benefited.

Eric 23:17

Right. This is all this is all to ensure that the male will continue to be.

Dr. Josh Stout 23:22

Exactly.

Eric 23:23

So that the offspring can survive.

Dr. Josh Stout 23:25

Right. But there is clearly some cost to the male. If you were the one male with a bone in your penis, you'd be more likely to have more offspring out there. But you're if you're not if a female is not needed to seduce you, essentially you're less likely to then take care of the offspring. So there might even be some cost to the male. But it's I think mostly I mean, maybe some benefit to the male, but I think it's mostly a cost to the male in favor of the females progeny because her progeny are then going to have more resources.

Eric 24:03

Yeah. I mean, this seems to this this evolutionarily seems to be placing the the decision of whether these genes continue on on the female.

Dr. Josh Stout 24:14

It puts a lot more on the female.

Eric 24:16

The female is making is deciding is this attraction going to work. Yeah yeah. If not moving on.

Dr. Josh Stout 24:23

Yeah. There's one more unique trait in males is.

Eric 24:26

The man will almost always just go through with it.

Dr. Josh Stout 24:29

Yeah. If he can.

Eric 24:30

If he can.

Dr. Josh Stout 24:32

Yeah, exactly. Yeah. Yeah. And the, the other thing is somewhat related to every member of the primates, almost every member of the primates and I think every member of the Carnivore have penis spines. Now they're there. They range from the nasty spines. Spines. Yes. They range from the nasty to the sort of bumpy, knobbly sort of French tickler kind of thing. So cats, for example, have backward pointing spines on their penis, which explains why cats are so strange.

The the entire when you're petting a cat, you're communicating with it in many weird ways. When you pet it on the top of your head of its head, you're saying you are dominant and it is a kitten. When you pet it on the side of its head, you are saying it is dominant and it's marking you as territory when it because its scent marks are behind the eyes. When you pet it down its back and it raises its button, the air it saying yes, mate with me even if it's a male. So again, these these behaviors can be stereotyped as female behaviors but have nothing to do with a gender of or sex. I don't know which ones which sometimes of of of the actual animal. So again, you know, evolution doesn't care. It's using stereotyped behaviors to do different kinds of communication. Now, the reason your cat will stick its butt in the air and then enjoy the petting and then turn around and bite you is because what a male cat does when a female is sticking its button air in the air and she's in heat, it will sort of press down and trot her and press down. That's also related to the nursing reaction. When kittens are nursing, they're they're going to press and knead on the mother's belly while they're nursing that very similar kind of stuff. But it'll be pressing down on the female. So it's taking one stereotyped behavior, changing it slightly into another stereotyped behavior. Then the male will start mating with her, but he's got backward pointing spines. And so while she really wants it, she also really doesn't want it and it's painful. And so then the next thing that happens is she screams and swipes at him and tells him to get out of there. And so built into the entire attractiveness of cats is I hate you. And so right from the very nature of their soul, they are both I love you. Come to me and go away. I hate you, you hurt me. So anyway, that's just built into a lot of the way sex is. It's strange in many animals in humans, it's very specifically designed to to make males less sexually responsive. Is the general theory. So these hairs are each one has a dedicated nerve, [Eric: Hairs? What hairs?] is what gives it the spines. And so so they're sometimes called neural spines. So actually.

Eric 27:23

still talking about a.

Dr. Josh Stout 27:24

Penis spine. Yeah. Okay. So on on a chimpanzee or a gorilla, there are going to be these these small, knobbly little like, hairy, spiny things. They're made of hair, each one connected to a group of neurons that stimulate the male really strongly every time that hair gets brushed. And so the males basically reach orgasm in seconds and then basically immediately do it again. And so it might might, might have sex 30, 40 times in an hour. I that helps if you have a penis bone and the spines make it really, really quick. So both of these things have been removed in in in human males. And so clearly there's some sort of an evolutionary advantage to males, both not having easy erections and having a really long time until having an orgasm. And so there's definitely something to do with pair bonding. We enjoy sex and the females enjoy sex. We're not like cats. They don't hate us for it while still desiring. So there is there is. This is absolutely when these pair bonds are being formed now we mate for life but not the way other things mate for life.

The female attitudes towards cheating, I think, are closer to what other mating for life organisms are towards cheating. But males attitudes towards cheating. We are psycho psycho people. We we will stalk a female. We're interested in. We will get incredibly jealous if any other male comes near her. If it's really not unusual in many cultures for if a female gets caught cheating, she gets killed.

Eric 29:13

So you're not you're not you're saying this isn't a cultural thing. You're saying this is a or a societal thing. You're saying this is a species.

Dr. Josh Stout 29:21

This is a species thing. Absolutely. Because think about it. If a if if a female is carrying another male's child and you need all of those calories for that big brain, that is a tremendous cost on the male. The same reason that male is not the pretty one, because he's doing a lot of work. It's going to be the same thing if he's trying to bring up someone else's child. So the the the the overall cost is tremendously high for a male. If he catches a if he's actually bring up a if someone else's baby. And the interesting thing is that while cheating has always happened in society and is fairly common somewhere around 20% of couples there's cheating. The rate of actual babies is extremely low and has always been so and so you can what you can do is you can look at lineages and then do DNA testing and not just look at, you know, paternity test for the immediate father. But you can figure out through an entire lineage if if, if the people are related to the family. So you look you look at a family and you look at it turns out it's it's very, very uncommon for there ever to be someone else's baby. So even though there has always been cheating in society, it's been very, very rare for a, you know, pair bonded couple, whatever you want to call that marriage for the female to have someone else's baby in that follow through and follow through with it and have the male then then raise it now, the females are still attractive and she's going to be very, very interested in getting a guy after she's had a baby, possibly. So males will sometimes be with someone who's already had a child. That happens, but they're generally going to be looking for someone who doesn't have a kid. That's how dating is today. But it is not impossible. But a female with a baby, if she can find a male, then she has a pair and she will still be attractive to him. And that presumably would be working somewhat hard for that.

Eric 31:23

And the reason that this isn't this way in the rest of the animal kingdom is that is presumably what you're saying, is that in most of the rest of the animal kingdom that the mother can have the baby and then the baby can just like climb on the back or grab on to the belly and then the mother can just keep going.

Dr. Josh Stout 31:39

Yeah. So there's much less parental investment necessary, right? You know, even in a cardinal where the male is helping take care of it, he's the bright one because he doesn't have to make an egg. That egg is so much so difficult. Now we know how hard making a baby is for a female, so that just implies the need for the male. It might not even be that the male is necessarily doing more work. It's just that she cannot reproduce without his help. So she's stuck. And it might not be, you know, if you think about what being pregnant is like as a male, I could imagine it, let's say, and what being male is like in comparison. It seems like being pregnant is way harder than the male's job in that really does. It really does. So why does the female then need to be the attractive one again? It's because she can't reproduce at all, right. Without the male providing some calories.

Eric 32:36

Right. And before we had, you know, contemporary society. Yeah.

Dr. Josh Stout 32:42

Yeah.

Eric 32:43

It was not a situation where that child could then climb on the mother's back and the mother could go out hunting or gathering.

Dr. Josh Stout 32:50

Right. And I have mentioned before that the Scythians, because they're such an interesting sort of counterexample when you put a woman on a horse and give her a bow, she's absolutely male, equal of a male particularly. She's had trained training. She might not be able to draw the bow as far, but she's probably lighter and faster on the horse.

Eric 33:09

And just as accurate.

Dr. Josh Stout 33:11

And just as accurate. So, you know, things balance out. And, you know, it turns out that a third of the Scythian martial graves are female skeletons. And so this was something that was, you know, very prominent in this society because of the way culture had adapted in that particular society. And because they were matrilineal societies, the assembly would have had groups that could have done the raising of the offspring without the need for the man to be doing all the providing. You know, once you're on a horse, you can go ride down something and you can have your sister do it while you're nursing, right? And so…

Eric 33:46

But the point is, the point is still you need you need help. If you just you’ve just had a baby…

Dr. Josh Stout 33:50

Absolutely need help. And so this.

Eric 33:52

Right, and again, you're also saying that this comes from our giant brains.

Dr. Josh Stout 33:57

It goes directly to really to the giant brains. What it's what makes us what we are. So just in the same way that women have beautiful breasts, men have smooth penises without spines all over them. Right. And no bone inside it. Right. You know, these are these are specifically a human and adaptations.

Eric 34:16

All of these things make it so that we can keep having these giant brains. giant brain babies.

Dr. Josh Stout 34:21

Yeah, giant brain babies.

Eric 34:22

And have dominion over all over the planet.

Dr. Josh Stout 34:24

As as they say. Yeah, we are certainly part of the planet. And we sort of forget that sometimes. Yeah, but that's a different show. Yeah. Anyway, I wanted, I just wanted to talk about that and introduce it as a, as a concept, like on an anatomical level, why our sex is just so different. Oh, we didn't talk about penis size. Okay. You know, men are very excited about their penis size, but it's directly related to, again, the giant brains because the vagina has to be bigger for the birth canal to be able to have a brain. So to match the two human males have unusually large penises

Eric 35:00

You mean compared to the rest of the animal kingdom.

Dr. Josh Stout 35:01

And certainly compared to chimpanzees and gorillas? There are other things out there. You know, whales have giant prehensile penises because they're like a you know, like they're like a mid-air refueling for a bomber. You know, they have to, like, go side by side. The, you know, penis has its own little sort of veins on it to help it locate. And it's prehensile, I think the largest, the largest penis to body size of any animal is the of course it's the Lake Titicaca duck. And it's I think it's longer than their body length. Again it's it's one of those sort of they have to do a yeah. Make things work in a complex situation but within within the primate. Yeah human males have very very large penises are I think I mentioned this when I was talking about mating systems. Our, our testicles are unusually small, not unusually large, but not incredibly large because we had to have some sperm competition. So again, in addition to male male competition, occasionally probably unsavory situations like, like an invading army kind of thing, Frequently males will meet with the same female within a 24 hour period of time. And then whoever produces the most sperm is most likely to impregnate the woman.

This is extremely rare in pair bonded situations. You don't normally have multiple males with a female. There's there's I think one culture in in in Tibet where there are multiple males with a female. But almost all polygamy is multiple females to a male. But with sperm competition you need larger testicles. So male's testicles are, say, larger than than a gorilla's, but much smaller than a chimpanzee. Because when a female moves into a what they call a male bonded society, they're all they're all brothers. Essentially, when the female moves in, every brother is going to have sex with the female.

Eric 37:04

Yes, we have.

Dr. Josh Stout 37:04

Man. Yes, exactly. And so they have really large testicles in comparison to human males. So we're intermediate between them. And it just you know, it's interesting to think about how we are different than other creatures in in terms of almost every other creature out there. You know, our penis and testicles are on the large side, which I guess would be nice. But it's it's it's bizarre. You know, they are hanging it right out there. The other primates are somewhat like that. But with, you know, larger penis and testicles, it's very obvious. So that's probably something that was part of the mating eye situation. But as far as I know, no one's ever been happy about getting a penis back. Whereas, you know, pictures of naked women, I'd never heard anyone really complain about it. And so, you know, you can see the differences in between attraction right there. So even though males have these unique pieces of anatomy that individually we might be proud of aesthetically as a species that we never really have.

Eric 38:07

But it's interesting, you're now positing a reason why this is something that males should be proud of it because because evolution is trying to get us. Yeah. Larger and larger.

Dr. Josh Stout 38:20

Yeah. And I don't know I it, I haven't seen any studies of, of of female attractiveness to, to penis size I but my guess is that it doesn't figure very large so to speak on I, I have you know I have heard from students whose husbands are urologists that there is actually a need for compatibility between male penis size and female vagina size. I but I don't I don't think it comes up very often given that most babies are way bigger than a penis. Yeah. So it's, it's, it's not that big a deal.

Eric 39:06

It's not, it doesn't really figure in the end. Yeah.

Dr. Josh Stout 39:10

Anyway, I just wanted to put some of those ideas out there and talk about why we are unique.

Eric 39:14

Also that that brings together many of the concepts that we've been, we've been talking about. So in the, in the past. So that was very, very interesting.

Dr. Josh Stout 39:23

All right.

Eric 39:23

Thank you, Josh.

Dr. Josh Stout 39:24

Thanks, Eric.

Eric 39:25

All right. Hey, folks, www.mindbodyevolution.info. Check out the website. Take it easy.