Menopause’s Role in Human Evolution: The Grandmother Hypothesis with Kristen Hawkes

Dr. Mindy Pelz  

On this episode of The Resetter Podcast, we dive into the grandmother hypothesis with the queen anthropologist herself, Kristen Hawkes. Now if you’ve been listening to me for a while, I have been obsessed on this hypothesis. It was first brought to my attention by Lisa Moscone back in the spring of 2024 when I interviewed her here, and what I’ve learned since then, of studying the grandmother hypothesis is that there is an evolutionary reason why female humans live so long in our post reproductive years. The grandmother hypothesis says that the purpose of the grandmother was multi faceted, but the biggest piece is that we were necessary. We are necessary for the survival of our species. We foraged for food, we took care of the young back in the primal days, and that there was a purpose to us living so long in these reproductive years, and Kristen is going to talk about that here. What’s exciting about bringing you Kristen hawks is that she has actually spent a majority of her career not just understanding this hypothesis, but also witnessing it in the Hadza tribe. So the Hadza tribe is a tribe in Tanzania that is displays this grandmother hypothesis in action. And so I got to ask her, first hand, like, tell me what you saw, because she witnessed these beautiful this beautiful tribe. What did you see there, as far as the hierarchy of men versus women, and what did you see about the necessity of women, of the of the grandmother and the post reproductive woman in the survival of the tribe itself? So I’m getting it directly from the resource who has witnessed this, which should be hopefully enlightening to you all. I loved this conversation. I also, at the end of it was really interesting, because when you dive into the grandmother hypothesis, you hear a lot about the only other mammal that lives as long as we live, are orca whales. And she talks a little bit about what she understands around the grandmother in an orca whale, orca whale pod mixed with what she saw in the Hadza tribes. So this is a deep conversation. It is all built around evolutionary biology. But most importantly, why I wanted to bring Kristen to you is that I nothing that the human body does is by mistake. Everything we are experiencing, whether it’s through our bodies or mind, has some kind of primal connection. And when we look at menopause, the reason that we live so long is because we can take the energy we were using for reproduction and now we can use it for other parts of our life. Specifically, we use it for fitness, we use it for cognition, and we use it for social development, as you will hear in this episode. So I’m so excited that we hunted Kristen down. I’m so excited to bring this conversation to you. It is deep. It is definitely one that is through the lens of an anthropologist. But most importantly, if you’re a post menopausal woman, what I want you to know is that the back half of your life has an evolutionary explanation, and Kristen is about to bring it to you. So Kristen hawks, hope you enjoy it as much as I loved talking with her.

Dr. Mindy Pelz  

Welcome to the resetter podcast. This podcast is all about empowering you to believe in yourself again, if you have a passion for learning, if you’re looking to be in control of your health and take your power back, this is the podcast for you.

Dr. Mindy Pelz  

so let’s start here, just you know for my audience, can you explain what the grandmother hypothesis is? So we can get everybody up to speed on that. 

Kristen Hawkes  

My temptation is to say that the usual textbook story of us is the hunting, paternal provisioning hypothesis, that what happened with these climate swings that actually started in the Miocene and these very dry periods, and then these swings in ancient Africa were breaking up the far.

Kristen Hawkes  

Artist, and that had effects on the plants that were doing well and the animals that were doing well. So there was all kinds of response to this, and a population that’s ancestral, both to us and to genus pan. So that’s chimpanzees and bonobos, some of those guys who then became our ancestors were drawn into the resources outside the forest, now in the forest where chimpanzees still live today. And same way with gorillas, same way with orangutans, all the great apes the babies can already feed themselves while, while they’re nursing, mom is carrying them along. She’s feeding herself. They are starting to feed themselves within their first year, and we now have chronic data showing the number of foraging bouts of these chimpanzee infants by the time they reach their first birthday is essentially the same that they’ll continue until they’re weaned, and then Mom will have another baby, and they’re entirely independent feeders. But the population that was drawn to these other resources, there were pay off foods that gave you a really high return if you were big enough, but the little wouldn’t do it. And right, that is what set up. I mean, there could have been a lot of extinctions or interesting but, yeah, you are mom, and here is the infant. Then if it can’t feed itself, then that is a problem for you. It will mean, oh, whoa. I can’t have another one yet, because I need to subsidize this one. But because the subsidies are not milk, it can be somebody else. And the older females whose fertility was ending, they’re still big. Their return rates are high. And we actually have data from these wonderful old Hadza grandmothers who are right old ladies, and their return rates are the same. Still, they are big enough and strong enough with these foods, and that means that their productivity, their economic productivity, can subsidize the fertility of the child bearing ages still, and so that means these two things then get favored by selection, increased longevity, post menopausal longevity, and shorter birth intervals. And those two things co evolved down the generations, and because we hung our grandmother hypothesis on these models trying to explain the broad variation in mammal life histories. You know, you think mountain elephant,

Kristen Hawkes  

there’s so much variation. You know, the ones that take a long time to grow up and are big, and then they live a long time and have babies at a slow rate, like elephants. And then the ones that boy, they really go fast, and they have as many babies as they can, because they’re gonna die? Well, I was so influenced by a theoretical biologist who had built models to explain that variation, and actually our life history seems so wait a minute, if you look at the relationship between adult mortality and age at maturity, which would be first birth in when we’re talking about, you know, this ape, we’re talking about people, right? Humans, yeah, humans who are foraging for a living. So the mortality regime is different than the one we live under. You know, no no scientific medicine, no public health and right? What is the case is that the relationship between adult mortality and Agent maturity in in in us is right where it ought to be in that model. And that was puzzling, because in the people through adulthood, females are continuing to produce offspring. Well, wait a minute, how can we fit that model, and yet,

Kristen Hawkes  

childbearing ends in us, and now we have these data showing it’s the same thing in chimpanzees, if they live long enough before 50, fertility is over. They’re going through menopause two. That is an ancestral condition, but they’re aging way faster, and they don’t usually make it to those ages, right? And, yes, right. And what happened in US was there was a fitness payoff for eight. Changing more slowly, because by subsidizing those grandchildren, you ended up having way more descendants. And that’s how natural right works, right? And so seeing that this model, Eric chanov, mammal model, that, wait a minute, we fit for that, it ought to mean, if we’re right, then we would not fit for the other invariant, as he called it, we ought to weigh higher rates of baby production, and that’s exactly the case when we have the demographic data to show it. And so there we were, yeah, with an explanation, but it was only the females, and it was then, by beginning to recognize and take on board. This is such an important part of the story, all of us, and this is true for sexual reproducers. Generally, all sexually reproducing things, including plants, if they’re sexual reproducers, right? And including hermaphrodites, are there all kinds of cool organisms that do things really differently, but are sexual reproducers? And if so, then everybody has one mother and one father, and they get half their genes from mom, half from dad. And every one of us and every individual in sexually reproducing taxa, it takes one haploid sex cell joining with another haploid sex cell to produce that cell, that zygote, that’s the beginning of a new individual. So half of it comes from dad, half of it comes from mom. That’s labeled, in general in evolutionary biology, the Fisher condition that has all these consequences, because it means half the genes in future generations come through males have come through females, and selection is working on everybody. And right, the various compromises that ensue from that are fascinating. And so once, and this was, well, you know, I again, it’s hard for me not to tell the long story of how,

Dr. Mindy Pelz  

right, right. No, you’ve been deep in the work. Let me, let me just say one thing in what I because I’ve listened to 1000s of your podcasts, I’ve been studying your work, and what I what I just heard, in what you just said, is that we have been so closely compared to chimpanzees, and that where we start to see that we vary from chimpanzees is when we look at menopause. And part of how I even got to your work is I kept asking myself, what’s the purpose of menopause? There’s a reason we live 42% of our life post reproductive Exactly. And every person I asked that to, nobody could give me an answer until I found your work and what I’m what I’m hearing and what you just said is chimpanzees, the young are able to feed themselves very quickly and post reproductive my understanding from your work is chimpanzees die within, like, three years or more after they’re reproductive. But that doesn’t happen to us, because the grandmother is so important for the survival of the species that we had to go 42.5% of our life post reproductive because it was the grandmother that has kept our species alive and that separates us from our chimpanzee friends, right? Well, right.

Kristen Hawkes  

Lots of it is. I mean, somebody like me is going to say survival of the species is not the way to try to think about things, because selection is all about competition within the species, it’s very okay which ones do better, and that’s what changes things over time. You know? I mean, Darwin, it’s amazing what he saw when he had so few tools. And, you know, astonishing. I mentioned ra Fisher so the combination of Mendelian inheritance and natural selection, it just gave us all these incredible tools to explain what’s going on. But what, what Jane Goodall did with when she was really getting to know those chimpanzees at Gombe, she said, I put the beginning of old age at about 33 because what she saw was that that rate of aging was faster in these chimpanzees than it is in us. So it’s not as the right females. Live to the end of their fertility and then they die. No, they are dying at a higher rate. So it’s actually very few of them who live through the end of their fertility, very few who live to and through menopause. But now we have these really cool data from this chimpanzee study site in Uganda, and go go where a few females are still alive, and therefore the hormonal signature of menopause in these females looks just like this ape. So like us, Wow, we had we thought that was the case from the data that we could pull together, and now it’s really been confirmed. Now we’re starting

Dr. Mindy Pelz  

to see a little different so one of the things I’ve seen in your work, and I also have gone back and looked at, you know, Margaret Mead, and like her menopausal post menopausal zest, is that what I think is not being highlighted enough. I feel like the conversation around menopause has been, you know, that we slow down, but when I look at the grandmother hypothesis, and I look at Margaret Mead’s post menopausal zest, there’s a redistribution of energy that actually gets used for our good. And my understanding, correct me, if I’m wrong, is that it falls into three categories, which is fitness, cognition and social. So what is it that we are getting so we as women, when we’re not putting that energy towards reproduction, that energy goes to another resource. Can you talk a little bit about

Kristen Hawkes  

that? No, I you know, again, the way I would teach this and try to explain to people who haven’t obsessed about this as long as I have, is that what light histories in general are all about is these allocation trade offs. You know, how much goes into this thing, because more going into that means there’s less into this other thing. And so that division between somatic maintenance, repair and growth. So building this organism, then keeping it repaired and maintained, that takes the allocation of whatever is available has to go if, well, how much goes there trades off again against how much goes into what’s called current reproduction. And so the trade offs there, well, first of all, it’s going to determine whether you should continue to grow bigger before you mature. And then I can say why selection would favor that sometimes it depends on adult mortality. I mean that those are the best models we have. But what is the case that that the more that the future pays off in fitness, the more there’s an advantage to be around to get the payoff, and that means action favors slower aging, more into somatic maintenance and repair and less into current reproduction. And that’s a history of our our somatic versus current reproductive allocation. So more goes into, well, first making us bigger. We’re bigger, yeah, or we before we stop growing and mature. And then, actually we put less into current reproduction. Others are contributing, grandmother right the rising, and so I put less as a mom and move on to have another and so all kinds of things follow from that as well. And I, you know, this is why I keep saying, how did it take me so long to see how these other pieces of what characterizes us are connected to exactly that suite of changes in life history, because it’s not only because we get half our genes from males, half from females, and so this increase in slower aging applies not only to females, But to males as well. And we’re mammals, and so in mammals generally, not just in us, females, get all of the cells that are going to turn into ova very early in life, this finite, and then it just depletes, you know, cell death as we go on, right? But, you know, apparently we lose half of them before we’re born in us. Yes,

Dr. Mindy Pelz  

I’ve heard that, yes, keep

Kristen Hawkes  

losing them before we start to men straight, continue to lose them. If we’re pregnant and lactating, we’re still losing them anyway that that is continuing to go on until, if you live long enough, then you. A longer cycle, because you’re not getting the suite of hormonal changes that would run a cycle. But in mammal males, they continue to produce new sperm through adulthood, and that has these huge consequences that with the increasing fraction of post menopausal females, there are also all these old males who are still fertile and therefore competing with the younger guys for paternities. And the only place they’re going to get them is where there are going to be babies, right? So, right, yes, there is crucial in two ways. One is, then you have way more males competing, and that has consequences for the strategies of male mating competition, which all kinds of, yeah. I mean, you can see this across the living world, in birds, so visible. But anyway, all the modeling that shows when you have this male bias sex ratio in the fertile ages, then the strategy that wins for males is to claim a female and defend her against the other males. And that interesting is a way in which we can account for this pairing habit that characterizes us and distinguishes us from the other living right, apes, from from chimpanzees and bonobos and so on, right? So we yes a do not do that. It is something you see in human populations everywhere. And then the age structure of that of the old guys competing with the young guys. So the old guys who are ahead in developing their reputations and so on, then they dominate the young guys. So we get all of these features that are characterized at recurrent features of the patriarchy, recurrent features. I was

Dr. Mindy Pelz  

just gonna say, like, the more I listen to you, the more I’m like and the wise. I believe that it’s the wise female elder that it needs to be the hero of the culture right now, because what I just heard is that even when men age, they’re still because of their reproductive status, they they don’t have this major shift that women get. And so it and and if you tie, I don’t know if you’ve ever heard Lisa Moscone, but Lisa Moscone is a neuroscientist that says that when we go through menopause and we lose estrogen, that the brain reorganizes itself, that the neurons that we needed to keep ourselves in people pleasing and keep ourselves looking, you know, attractive to the culture, get pruned away, and new neurons come online that give us more of a social lens. And when I look at her research with your research, I’m like, wait a second. Hello. The menopausal woman is the evolutionary heroine here. She, instead of tossing us aside, people should be embracing us because of if you just looked at our design, we are incredibly needed for the culture. So that’s how I see. What you just said is that it we are in a category as post menopausal women. We are in a category of our own because of this evolutionary design that we are built upon. We are

Kristen Hawkes  

we are in a category of our own. But it is the case in socio ecologies like ours, the tendency that, oh, wait a minute, I don’t want my gray hair to show. I don’t write all of that kind of thing that goes with living in a socio ecology where youth is absolutely considered to be so important, yes, and especially when it comes to females and so all of the things that characterize this tendency to want to still be considered sexually attractive. All of those things are a part of the socio ecology we live in, and the life history that is has characterized this animal, and it is the reason that we have, well, all kinds of both pros and cons, because one of the one of the things that goes with this, not only the male strategies, which initially I did. I mean, I thought these were two interests of mine. What’s going on with male strategies and the life history stuff? And I thought separate lines of research. And, boy. Am boy. In the last few years, I’ve seen no those things are so connected. We’re in

Dr. Mindy Pelz  

a category of our own. Yeah, well, but

Kristen Hawkes  

the two things are so linked to the grandmother hypothesis, can’t explain what the boys are up to, right? Yeah. And the other thing I mentioned, this is a different angle on brains, but the thing that goes with our slower development is also this, this slower neurogenesis, which results in the much bigger brain. But here are babies in our radiation that are maturing more slowly. So as I was saying, these chimpanzee babies are already before they’re one. They can do all this stuff. And where one year old, you know, human babies, I’m just a baby, but because the life history shift includes this earlier weaning, and that’s so crucial to why the slower aging and the post menopausal longevity was favored because there were then more grandchildren, and therefore more copies in the future, The babies who are developing so slowly and now mom is having another one, and yet I am not able to even come close to think about feeding myself and therefore, and this is where Sarah herdy had laid this in front of us almost a quarter of a century ago. And yet making this connection, and I have been so influenced by her in so many ways, but connecting these pieces, you know, I still why did it take so long, but so selection on babies to make the social relationship more important than anything? And the thing about human babies is this social precociousness, smiling, trying to, you know, somebody attract, am I not? So, yeah, that, that is

Dr. Mindy Pelz  

the mirror, the nd, the mirror neurons, like, Yeah, there’s definitely a draw to the adults around you as a human baby, absolutely

Kristen Hawkes  

and trying somebody be sure to invest in me, Mom. Mom. What about me? Yeah, stuff which is not going on in the other apes. That’s not an issue. And right interesting was how selection on that social engagement, the importance of it that it’s a survival was a survival strap in these ancestral populations, for babies, and as a consequence, selection for all this social stuff, when motorically, everything is so slow, And that results in this early wiring of our brains to make the social relationships take priority over it and end up amazing and I are doing right here. So there’s appetite, or can we connect? Can you see what I’m talking about? Yeah, you get what I’m when you doing the same to me. That’s yeah, close with this live history

Dr. Mindy Pelz  

that started. Yeah. So, okay. So go back, if we go back to, I call it cave life, go back to the primal days when, when the hunters went off, it was it mostly the men that went or was it older, you know, teenage girls like or was it primarily the men that went off to make the big animal kill?

Kristen Hawkes  

It’s, it’s primarily the men and one of the things. So when I first was doing ethnography with people who know how to do that, who flourish for a living, right? But that was the story of us, the hunting hypothesis, the paternal provisioning hypothesis, right? Famously, brilliantly synthesizing what everybody thought they knew in the last century about both foraging, popular, you know, people who were foraging for a living, and the other apes. And this story that, well, if you look in other primates, you see mom and infant, and it might have a social relationship with the older one, and then what happens in us is dad is there to bring home the bacon and to subsidize his wife and kids. And that explanation for nuclear families was, it’s still in the textbooks, but the data so clearly show that is not what happens and and our research has provided this quantitative data showing that, boy, when you go for those big animals, if you’re successful, it is a bonanza. Everybody is so it. Excited about it, will take advantage of it, but you fail almost every day. So when you’re successful, it’s huge, but if the kids have to eat every day, that is not going to do it. And what turns out to be crucial. And our again, our Hadza data quantitatively showing this and and James Woodburn, who had started as an ethnographer with with these foragers in in northern Tanzania, these Hadza folks in the in the 50s, he had actually written about all this and talked about how well the women and children go off and feed themselves, and then, and then the men, they go off individually and get plant foods to feed themselves. And then they really go to work, and then they are competing with each other to show that they can get these big animals. And everybody knows who the really good hunters are, and the guys who are the really good hunters. Well, nobody wants to cross them. They want to make sure that they are somebody who would be an ally. And so so all of these reputation things that are hugely important for the males, that have consequences for whether or not they can make this claim on a female, and the other guys will say, Okay, I see you got, you know, you right, I’m back right.

Dr. Mindy Pelz  

Oh, because they’re like a cave hero now they’re like, I came back with the kill. I get the I get to feed. I get and I get the woman. I get the the fertile woman.

Kristen Hawkes  

And my, I’m collaborator on this project, Nick lerton Jones, who’s whose demography, you know, it takes so long because to really get the numbers on these things right, but, but now we have those data showing that the guys who have reputations as as better hunters, they end up with, well, first of all, when they’re when their current wife is her fertility is ending, well, then you know, they get another one. And then the tendency is for the guys who are better hunters, to spend more of their life sleeping with a woman, right? Being married, okay? And they end up grabbing more surviving descendants, not because their kids eat better, but because they have more kids. So all of that come together. Interesting biography, showing that the survival so Nick now we had the we had the weights data, showing that, well, first of all, these old ladies who are so amazing, and seeing their return rates for this very energetically expensive thing of digging these usos was essentially the same as as the younger women, but they spent more time at that. And so then we could see, because people let us weigh them. I mean, they were wonderful. And so we were waiting Hadza

Dr. Mindy Pelz  

these. This is the Hadza tribe that you’re talking about,

Kristen Hawkes  

that’s right. And we were weighing, I wish we’d done it more often, but anyway, we were doing that, and people were, you know, letting us do that. And so then we could actually see that how well the kids were growing. So this is, remember, the other apes, where the they’re already feeding themselves well, the little kids are trying, but they’re too little. And it turns out that the growth rates of the little kids was correlated with how much their mother worked until she had a new baby, and then that disappeared, and it was grandma. And so that very trade off between what the subsidies coming from the older females meant for having another baby sooner, because then the older one is not completely left in the lurch right now that that kid will be subsidized. So all of these things that shifted in the life history go with that adjustment to depending on foods that the little kids can’t get. And the standard story is it’s all about hunting the big animals. Well, hunting animals is important, but it is not what feeds the kids. Yes, right, a lot the women are doing and windy, and had described this in 50s and and yet, you know, still that hunting paternal provisioning hypothesis, it’s still the one that continues to be favored.

Dr. Mindy Pelz  

Let me tell you a couple of interesting conversations I’ve had that back up your hypothesis in different ways. So what I hear you saying, and this is what I’ve that supposedly, what 3% of the time, the men came back with some kind of big animal kill, which meant that somebody else had to be giving providing food for the mom who’s pregnant and the little kids. And that. Is the grandmother, and then the grandmother, what she was able to gather was tubers and plants that she could pull out of the ground to bring it back to feed the the mom and the kids, and probably feed the the male hunters when they didn’t come back with a kill. So she was providing sustenance for the the the tribe, because the big kill wasn’t happening all the time. So let’s start with that. Is that accurate, that it was the grandmother that was keeping everybody alive?

Kristen Hawkes  

What? What our data show and and again, this is what Woodburn also described to the Hadza. Is actually the women and kids, including pregnant women and and little kids, they go off together, but it is the way in which the productivity of these resources means they’re getting a high return rate. And they eat at the site where they get it, and they actually end up bringing as the wood burns language was after they fulfilled their hunger, if there’s any left, then they bring it back to camp, but not to feed the men. It is just likely to be eaten by the women and kids. And the men go off individually periodically, and they know how to dig tubers. They were little kids, and they are feeding themselves on these other reliable Plant Resources. And as Woodburn said, and our data showed this too, that when a guy goes off to supposedly go for a big animal, that’s his real target, but if he happens to kill a small animal, he’s very likely to cook it and eat it right there and not right

Dr. Mindy Pelz  

there. He doesn’t share it right so, what is it? What is it about the grandmother, then in this because it’s her brain, her ability, because she doesn’t have all the energy going to reproduction, that she becomes pivotal in this food foraging system that was, was a was a make or break moment for our evolutionary or what I call our primal friends. So what was it about her that was so pivotal to nourishing like, what is it in her that allows her to have that extra zest to be able to find food for the tribe. Well,

Kristen Hawkes  

I you might, you might find other people who will have ideas about that, the way I think of this. And, you know, again, the women I was watching do all this is, this is what you do, sort of WoW, starting. I mean, it was, it was the what, what would we call these, these girls who haven’t had a baby yet, and they’re actually there, but they’re, you know, beginning to cycle, maybe. But actually, age at first birth in in these foraging populations is about 19. You know that it’s not we don’t stop, and it’s not because they’re not having sex when they are ovulating and they are, chances are they’ll get pregnant, but it’s but it’s girls in those nubile ages who actually their rates are lower, and it seems to be that they’re paying less attention to the work, and often they’re holding The baby up in there, if, if a woman is strapped at cursing a baby, you know, then she’ll have the baby. And she doesn’t stop foraging, but she’s not getting as much, and that is associated with how her wean kids are not then, depending on her, it is the work of the grandmothers. But if here is the where you know from my experience, which is that the women are together, and this kind of food is one in which you don’t have the feeding competition that can happen with pansies, where females actually try to stay away from other females, because the you know, somebody else who’s trying to eat the same soft fruits and leaves is competing, right? But when you are going for things like these Usos, then actually digging next to somebody can raise your rates, because you start and you’re just, you know, you have a digging stick, and you’re just, yeah, being there until this thing actually gotten into started to dig a hole. And because of the way these plants grow, you have a whole bunch of of tubers, you know, like potatoes. So somebody digging right next to you means your rate, you know, it’s this Sigmoidal thing where initially it’s low, and then it can really go up. And it can go up faster if you and somebody else are digging next to each other. And the way in which things went on when we were, you know, people were so wonderful, timing everything and weighing everything was that you would, you dig a batch, and then you. Get together and everybody eats there together. Yeah, everybody’s there, and the little kids are there, and they’re taking advantage, yeah, the fact that there is this pile of food, and so they that’s how they are consuming it. And what’s happening with women is as their fertility is ending, then they are continuing. Given we have evolved to be aging more slowly. They are still big and strong and still putting stuff into the piles, but they’re not putting any new little mouse and stomachs, right? It is their continuum, addition to what’s available that allows the younger females to then have another baby sooner. So that’s how

Dr. Mindy Pelz  

so the Hadza tribe that you that is our modern day version of the grandmother hypothesis, when you when you watch them, was the grandmother considered purposeful? Was she considered to be really important to the tribe? Was she lifted up? Was there some kind of societal like honoring of her that we don’t typically do in our modern day world,

Kristen Hawkes  

I would see the answer to that is no, although are very feisty, so yeah, and but I would say it is the case, you know, I just, I think of times when, particularly a few women would really when there was some kind of hoo ha going on be have be in the argument. But no, I would not say that there’s any sense in which old women are revered within my statement. So

Dr. Mindy Pelz  

one of the things that when I really dove into looking at the grandmother hypothesis, the way I looked at that was that the culture needed the grandmother. She was pivotal for this, the the whole tribal experience and and the for generations to continue on, if you juxtapose that to what we do to post menopausal women now we, our society tosses women aside. And one of the things I want to redefine with aging is that actually, if women understood that in their post menopausal years, if they understood their brain, if they understood this regeneration of energy that they were getting back that they would see the importance that they had in the post menopausal years. But our society doesn’t look at that. So I am curious if things like Alzheimer’s and dementia, if that happens, or this obsession with anti aging that so many women have, if that is happening, because we feel like we’re going to be tossed aside by our culture, whereas if you look at the Hadza, you look at the our primal friends, that wasn’t the case ever. You just moved to the next evolution, evolutionary need for the tribe. Do you have any feeling on that and how it compares to how we handle menopause today.

Kristen Hawkes  

Well, I think the way, the way we look at it today, I completely agree, is, you know, I mean this, I think it’s really sort of creepy when I see, you know, older women who’ve had all this work, and, you know, right, would think they are 12, and, you know, I just Whoa. I wish that isn’t what was going on, but I understand it and all kinds of contexts in which the stuff that you need is actually controlled mostly by males, then finding ways to connect to male is a way to this stuff, well, that you need, will need for your kids and and so the the whole pattern of the kind of sexual division of labor in, in, in, quote, traditional societies that says, you know, men go forth and bring home what then feeds the domestic worker that is mom. Well, in in foraging societies, women are providing the crucial resources that are reliable and provide what the kids need. And again, it is not unusual in human societies to mark menarche. You know that that there are various kind of ceremonial things around ceremonies? Yeah, yeah. But the general pattern, and there actually are a bunch of feminist ethnographers who, who would be, I mean, this is so interesting, because I think the bio. Biology explains what they’re talking about. But for the most part, they would say, No, didn’t get the biology out of here. This is just culture and or not, etc. But who have talked about, well, actually, the role sex plays in the politics of what we call egalitarian societies. And egalitarian they complain. And these are people who say, you talk about this society I study, and call it egalitarian. It is not egalitarian that the relative position of men versus women is really different, and there is a lot of sexual talk around everything that goes on politically, and the main thing men fight over is women and being dissed because so there’s coming back to this thing that I was talking about where men competing for their reputation, the older guys are always ahead and then dominating the younger guys. And you know, there are all kinds of ethnographic examples of what the old men do to the young men to keep them in line. That that’s all part of the same story.

Dr. Mindy Pelz  

Wow. So when I hear that, I’m like, is feminism ever going to stick in a culture where we are have this evolutionary design built within us where the man is is got this status and is bringing home the bacon, and the woman is the one trying to attract him. Like when I hear you talk, I’m like, wait a second. Whatever could happen in our human life that would make us equal is almost going against our evolutionary biology. And I hate to say that is that,

Kristen Hawkes  

like, what do you think of that? I have this amazing student who, after the election, said, Oh, this is, it’s so horrifying to have been, right? But I we just again the resurgence of patriarchy. I mean, I mean it is. And look around the world, it’s so I right around the world, it continually repairs, sometimes in just these really virulent forms, right? But that there are places where it is not the case that the what the old bank can do to the young men and you know, so all these complicated conflicts of interest and trade offs, they depend and they take different shape in different socio ecologies. And I, I focus especially on the ones that are pre Holocene, because that’s how we got to be animal. But the thing about recognizing that it’s actually midlife menopause that, in a sense, is is where patriarchy comes from. You know, realize that that’s so important. It’s just the center of so many things. You know, I think that thing about the socially precocious babies that is a consequence of mom moving on and having another baby while you still can’t do anything. And, boy, if you don’t get somebody, mom come back somebody, then that’s curtains. And so that’s, yeah, it’s like a hierarchy,

Dr. Mindy Pelz  

though. So so when, when we look at the grandmother in these tribal situations, one of the things that I noticed, and so, you know, my world has been fasting, and I’ve taught millions of people how to fast, and the person that does the best with fasting is the post menopausal woman. And when I brought this to Lisa Moscone his attention, she said yes, because after estrogen goes down, our brains become less sensitive to glucose. So when I go back and look at the grandmother hypothesis, I’m curious if, as the grandmother was grabbing these tubers. What did she feed the children and the fertile women first, and then whatever was left over she ate, which forced her to have to go longer periods without food. Do we have any sense of her frequency of eating back in those days?

Kristen Hawkes  

Well, again, in my experience, what happens is everybody’s eating as much as they can, and it’s only what isn’t that goes back. And one of the reasons the big animals are such a big deal is people come to the kill site and eat their enormous amounts, but it’s so enormous that there’s still a lot left. And so that’s comes back to camp, and these are all things we have measured because of, you know, questions like this, what the hell is going on? But when it comes to eating every day, you know, again, to simplify that, what, what the adult men are doing in our experience with the hot zone? Again, this is what Woodburn described, where. Working decades earlier, so that that, that the men go off and they know how to acquire all these reliable things and feed themselves. And again, if they get a small animal, that’s no big deal. They just cook it into your brain. And if right there, well then, you know, then they’ll bring it back. But that might just as easily go to the other men, as opposed to any of the women and kids you know, as Woodburn said, but the real deal is to try to be one of the guys who hits a big one. And everybody knows who it was, but what you get for having done that is the credit you don’t have any special right to the meet everybody you know this, everybody eats, you know, I’m one of the people. Where’s my and this is another thing about, about Hadza etiquette, you know, it’s very insistent people, where’s mine. So the notion that that, and I think we do know, in some kinds of socio ecologies where mom is responsible for the hot meal, and then dad eats first. And you know, there are places where that is the pattern, but a guy who’s just had so many good ideas, and I think he’s right about so many things, but wrong about this, Richard Wrangham, who actually what we know about chimpanzees, a lot of it’s where, you know, Richard is responsible for it, and his setting up this field site Kanye war is so important, and his students and so on. But he actually has said in a book that men can afford to go off and do risky things, because when they come home, there will be, you know, the little lady will have not those story from my experience with foragers, that is not what goes on with the Hadza and not what goes on with the HT and so that not interesting. So the and again, in my experience, it is not the case that older women eat last, because the women and children are all eating together. So it’s not okay, great, not, you know, again, they are not feeding the men. The men are feeding themselves, feeding themselves, yeah, and on, you know, on the reliable resources. So the big deal is there are certain kinds of things that are reliable. If you go for it, you won’t fail. And of course, that’s crucial. If, unlike the other ape babies, who can the kinds of things that that everybody’s eating, that mom is eating and feeding herself as she carries you along while she’s nursing you. Those are things you can manage. And it’s also the case that this life history shift to slower development. So what those infants, their motor capacities, are more developed at ages than our babies, because, again, this life history has slowed development, which has had this consequence for our size of our brains, and the size of the neocortex, and all of that, you know, begins to tie in to this life history. And again, my, my, you know, I’m memory is always dangerous, right? You know my, my followers, with, with Hadza women that, in fact, you know, as as tubers are pulled off the fire after pretty short time on the fire. And often these are everybody’s youth sharing the same fire. And then, you know, the pieces are. Everybody you know, reaches out for a piece and and the little kids

Dr. Mindy Pelz  

get in there. There’s no hierarchy to that. Then there, everybody’s eating what they can eat, yeah. So when you’re looking at the HUDs, the the grandmother, as far as her fitness level, like, if we look at the Western culture, there’s this understanding that as we age, we’re gonna our fitness level is gonna go down. But I’m also curious, that’s because we’re sitting all the time and we’re not having to be so purposeful with our bodies. What did you see in those grandmothers, as far as their capability of fitness that we might glean some insight as to how we were designed. Our fitness was supposed to be in those post menopausal years, right? Well,

Kristen Hawkes  

this is where language gets in the way, right? Because there’s fitness in the sense of physical condition, right? And then right sense of gene copies in the future, right? And those are not the same thing at all. And actually some really interesting data has come out recently on the this aspect of things, comparing energetic expenditure between actually Hadza folks and, you know, North American couch potatoes and so this Hans work. And. Knowing that actually, when it comes to total energy expenditure, it’s not so different if you control for age and sex. And so the issue about American obesity is all that food. And as Herman says, you know, odds of food is not that good, so I disagree with them. I like potatoes, but we are obsessed with all kinds of delicious things, and you can hardly go to any kind of social gathering without being invited to have something. And then we celebrate with big feasts that include a lot of fancy stuff.

Dr. Mindy Pelz  

And are the women in the Hadza tribe as they age. I mean, they’re still very physically active. They are, is what I hear.

Kristen Hawkes  

Yeah, absolutely, absolutely. But again, this is the thing, you know, the contrast, big contrast, well, across the primates, that if you’re a monkey, adult mortality is higher. You mature early enough not to die before you have kids, and you end up being smaller and so on. But if we just look at the great apes and that, so this hominid now, now we’re all in the same hominid family, US and genus pan. So that’s chimpanzees and gorilla, or chimpanzees and bonobos, gorillas, orang tangs. We’re all hominids, and hominids are the biggest. Have the greatest longevity of all primates, and they have the longest birth intervals. Well, we have even greater longevity and mature even later, and we have much earlier, much shorter birth spacing, and that yeah, grandmother’s fingerprints says, yeah. That the thing that has favored the post menopausal longevity, the slower aging generally. Because remember Jane Goodall saying, you know, I’ve 33 is the beginning of old age. And I see all of these ways in which it gets difficult to climb trees and then, you know, you’re subject to the insults that are going to kill you. You get to be old and rarely outlive your fertility, if you’re a chimpanzee, but what happens in us is if you make it to adulthood, and of course, unfortunately, there are some human populations where that’s tricky. Make it to adulthood, but once you do, the chances of outliving your fertility if you’re female, are way better than chance you are going to outlive menopause? Yes, if you’re male, you will keep producing sperm, and that sets up all these other things about male strength. Yeah. Would

Dr. Mindy Pelz  

you say that one of the challenges right now with menopause, I mean, menopause, is having a moment, and we’re talking about it like we said, Do you feel like we’re living menopausal women are living at a little bit of an evolutionary mismatch to our design, between the way we’re treated by the culture, to the type of food that we’re eating, to this understanding that, oh, you’re, you know, as you get older, you should be slowing down. Is there some kind of evolutionary mismatch that we are not connecting with when it comes to our post menopausal years? Well, I think

Kristen Hawkes  

I am. I think I had a paper in 2003 so that’s a long time ago. Then anyway, what I was underlining in in that paper, I think it was grandmothers and the evolution of human longevity was how even we tend to think of retirement age as 65 right? And, and that is well past menopause, right? So recognize aging is absolutely well. Do we recognize it that one of the one of the misunderstandings, and I always try to hit this with students, it’s so easy for people who who know stuff. I wish I knew you know, who really know all kinds of stuff. Really smart to think that life expectancy is a measure of whether there are any old people, because life expectancy as a as a demographic parameter is, is the average lifespan of everybody born at the same time. And if you have a population where there’s a lot of infant and juvenile mortality, then you have all those really short spans that go into the average and make it really bring it down. All right, yep, like, let’s see, in these foraging populations, is at birth is well less than 40. And yet, if we actually look at the age structure, about a third. Food of the adult females are past their fertility. So it’s so easy to get confused by the demographic numbers. Even George Williams, who was so influential as an evolutionary biologist, to me, very important paper in 1957 about senescence, about aging, and why it varies so much living world. I mean, it’s a huge contribution, really, brilliant. But having laid out the theory, then, he said there should be no post fertile lifespan, life in the normal lifespan of any kind of animal that’s characterized by what I’ve been talking about. And then, having said that, he said, Oh, yeah, what about menopause? He was writing in 1957 where everybody thought menopause was unique to us. We didn’t have any of the data we now have on the other apes, where we didn’t have any of this demography from people living under mortality regimes of hunting and gathering. And what he did was brilliant scientists, and that he was, he tried, were there any old people in the past? And he used what paleo demographers were saying at the time, they were using these skeletal assemblages and trying to age them from the Upper Paleolithic, and actually the Mesolithic, and saying there weren’t, and that has all been blown up. They were doing correctly. And so the recognition that actually a life history like ours is very old, that Gina’s homo. I mean, the thing that I’m trying to really underline this thing about committing to the kinds of foods that the babies can’t feed themselves on is just a huge game changer. And that is what means. Then genus Homo gets into all these places in the temperate old world and gets

Dr. Mindy Pelz  

interesting because of that. Yeah, yeah.

Kristen Hawkes  

And that’s grandmother effects, right

Dr. Mindy Pelz  

Yes, that’s right there. What is the orca whales? We hear that they are the only Yeah. Where do they fit into this

Kristen Hawkes  

so interesting? I mean, those cetaceans in general are just fascinating because they have these enormous brains. But it’s just so difficult to, you know, to really study them, but, but, well, actually interesting that you mentioned that because it’s really a pretty nifty paper by, I think Ellis was the first author. This was maybe a year ago or so. And the person who who had the comment on the paper is somebody who I think knows all what stuff that I know. And I was surprised to hear her use Williams as the source of the grandmother hypothesis, because that’s a thing. He one of the few things he got wrong, but he got that wrong, but, yeah, no, the orcas are actually the orcas. The big mystery for me with the orcas. And we’re finding out interesting new stuff all the time, but there’s so much we can’t because it’s all underwater. You know, it’s just right when it’s possible to see this, but the way they build their life tables is, is worrying, and the mystery from a life history theory perspective, is because they are sexual reproducers. So one father, one mother, and so all the genes are shared by both males and females, and yet their age specific survival curves make it look like the males are all dead at the age that female fertility ends, and then there are all these older females, and yet it’s the quote, really big males that are getting most of the paternities. And so that sets up a real riddle, because that should mean selection would favor that those guys would survive, because way more companies are going into future. So, so, yeah, so many interesting questions about about the orcas. And there are a couple of other taxa where people think they have post fertile females surviving. You know, they have a really interesting social organization the orcas do, where everybody stays home and where, you know, males go off and and compete to mate with females elsewhere, and then they come back home, and the sisters are fertilized by males from elsewhere, and, and, and, you know, every once in a while, there’s just an amazing sort of anecdote that people record about orcas. This was off the coast of California, where it just happened that the Orca watchers were out there and they saw this male going after a female who had a really new baby and one that was a little older, and he was trying to kill her. So this in fantasy. Other thing we know is a thing in primates, so our order, that is. And you know, the whole issue around female counter strategies, given that males can be dangerous, then you better fuck them all, because if they have a chance, then, then they won’t kill it. So I love Sarah herty is calling that being assiduously maternal. She’s so good about that. But here’s the orcas in which here’s this guy trying to get the baby, and he fails, and then there’s another attempt, and it turns out that his wing man in this attempt is his mom, who is there helping him knock off the baby? Wow, but get the next paternity. So, yeah, no, there’s so much. So

Dr. Mindy Pelz  

we may not want to compare ourselves to orca whales. That’s what I just heard of that.

Kristen Hawkes  

But bonobos, you know? So another, another, closest living relative. We have chimpanzees and bonobos. And bonobos, it turns out they’re way more similar than anyway, or I could just go on and on, but anyway, in bonobos, female alliances really play an important role. And it turns out that the paternity skew is even higher in bonobos than it is in chimpanzees. Some males getting a larger fraction of the paternities and and the way in which some males get especially many is if their mom is high ranking. So, you know, mom, interesting.

Dr. Mindy Pelz  

It gets complicated. Yeah, to finish this up, what you know, the grandmother hypothesis has been getting more and more attention as menopause is coming in, being able to be a something we we can chat about now. What are you hoping your work with the grandmother hypothesis? What are you hoping that will do to the Met the current menopausal conversation? What are you? What are what are your insights in how that can help those of us that are navigating our aging years now in this post reproductive state, what can we learn from this hypothesis? Well,

Kristen Hawkes  

I think the more we know about human life history and how it shapes all of these features of us. I mean, the obvious question is, so what if you know that here we are, so Right? But among the things that go with being this kind of ape are some things that we really value and cherish. I mean, like this, like, Am I making sense to you? Do you, I mean, this is for us talking to somebody, yeah, you’re really connecting. Is just such a light, but it also can be associated with as you’re growing up. How, how is it that we do that? And I want to, yeah, am I going to fit in here? And what should i And so learning how to do it right means, okay, that’s our way. Them, they don’t do it our way, and we get this really scary, us versus them, and tag dangerous to each other and the planet as part of our capacities and tendencies as this and understanding what’s going on doesn’t make it go away, but one of the things that maybe it can do is make us more charitable toward each other.

Dr. Mindy Pelz  

Yeah, I mean, what a great and that, you know, that’s how I fell in love with your hypothesis, because I was like, Wait, here’s the purpose. There is a purposeful reason we spend so many years in the post menopausal years, and that’s what I

Kristen Hawkes  

absolutely this has evolved. Because it meant, yes, there were more descendant copies of this it succeeded against, which is why back again to natural selection, being this competition within a tax on, you know, rather than for the good of the species, because it’s all of that is going on all the time, you know, which, given the current circumstances, which variants tend up doing better, and then there are more copies of them, and then the whole thing shifts in, right. Yeah, right, yeah. Well, and colleague of mine, I guess, at Utah, although she’s in psychology, Lisa diamond, her her focus in her research has been sexual fluidity. She started out being especially interested in women, but then started studying it in men, and finding there’s a lot of sexual fluidity in everybody. But she and her co author post docking with her, whose name I’m forgetting for a minute, but I will think of that they have recently made the argument that based on an. Done the analyzes of data sets in which they can control for all kinds of things that might affect aspects of health status, and what they find is, when you control for all of those things, you still find that stigmatized minorities, gender minorities, racial minorities, that still you see the health disparities, and their hypothesis is it’s the stress that goes With the absence of social safety. And what I have suggested the Lisa, and since she hasn’t done it, I’m suggesting it myself in print. Extending that hypothesis to there is what’s called the Health survival paradox. Do you know about that? In No, I don’t that. In all kinds of context. So what you see is that men, well, actually, it starts way earlier that boys, I mean, and then I could talk about it whole other topic I don’t want to get into. But anyway, that that mortality is higher in males than than in females throughout and yet female females are sicker. So that’s the health survival paradox, and extending Lisa’s hypothesis about the stress associated with concern about social safety, given all the things I’ve been saying about

Dr. Mindy Pelz  

that interesting, yeah, or

Kristen Hawkes  

you never know. And I am talking to a colleague of mine said, you know, if you’re ever, if it’s ever an evening somewhere, and people have come to a lecture hall and then you are talking about stuff like this, just ask the audience if women walking alone to their car in dark are way more worried than if they’re with somebody else, or if a man is walking to his car and and there again, there’s all kinds of data. People studied a lot of this stuff a while ago, and it went out of fashion. But the advantages of having a bodyguard mean that there may be things going on among the males where claiming proprietary, I don’t know, ownership of this woman is in his fitness interest, but and actually, this is a thing Nick has said about, you know, paper, a paper of ours about about divorce rates among the Hadza, that actually, given the fact that what women are doing at the work they do, is so important to the welfare of their kids that being able to say, see my wedding ring. No, I mean, they don’t have wedding rings, but don’t hassle me. See I’m I’m, it makes her safe with that guy, and therefore leave me alone.

Dr. Mindy Pelz  

Fascinating. It’s so fascinating. I mean, my what I learned in teaching the world about intermittent fasting was that when we go back to evolutionary biology, we find a lot of the answers to the health challenges we’re having today.

Kristen Hawkes  

I completely agree. I mean, that is, you know, for me, I started out as a garden variety cultural anthropologist, and it was only, you know, a series of lucky breaks where I was led to, wow, go back to evolutionary biology and just, just cover the powerful tools. I mean, I you know, wow, we can explain age. We can explain Yes, that is so yes, and it is very exciting, you know, be One surprise after another. No kidding, we can explain that too.

Dr. Mindy Pelz  

Yeah, right, exactly.

Kristen Hawkes  

So maybe we’ll talk again. But I really look forward to seeing where you end up going with all of this. I mean, thank you, yes.

Dr. Mindy Pelz  

Oh yeah, no. I just, you know, when I watched the world heal using fasting, it really got me thinking there’s a reason the body does everything, and we have to pull it out of the modern context and get it back into this evolutionary state to truly understand it. So, so thank you. I mean, this is I’ve been, I’ve been listening to your podcast, I’ve been reading your papers. I mean, I’ve been stalking you, and you don’t even, you’re not even aware of it. And yeah, I will keep you posted on the next book, and I will reach out. But thank you for your work. You know it’s really it’s beautiful to see it being highlighted. Thank

Kristen Hawkes  

you for yours. Yeah, yes, the communication skills are so crucial. So agree for being an effective communicator. I. Thank

Dr. Mindy Pelz  

you so much for joining me in today’s episode. I love bringing thoughtful discussions about all things health to you. If you enjoyed it, we’d love to know about it, so please leave us a review. Share it with your friends and let me know what your biggest takeaway is. You