The Menopause Mystery

38m
Until recently, scientists assumed humans were the only species in which females went through menopause, and lived a substantial part of their lives after they were no longer able to reproduce. And they had no idea why that happens, and why evolution wouldn’t push females to keep reproducing right up to the end of their lives. But after a close look at some whale poop, and a deep dive into chimp life, we find several new ways of thinking about menopause and the real purpose of this all too often overlooked second act of life.

Special thanks to Danielle Friedman, Rachel Gross, and Kate Radke.

EPISODE CREDITS: Reported by - Heather Radke and Becca BresslerProduced by - Sarah Qari and Becca BresslerFact-checking by - Emily Kriegerand Edited by  - Becca Bressler

EPISODE CITATIONS:Books - Check out everything Heather Radke writes, including Butts: A Backstory, cause it’s all that good, here: Heather Radke (www.heatherradke.com).

Find any one of Lucy Cooke’s book, including Bitch:On the Female of the Species, here: Lucy Cooke (http://www.lucycooke.tv/)And check out everything Caroline Paul has on offer, including Tough Broad, here:  Caroline Paul (https://www.carolinepaul.com/) Socials - Heather Radke: https://www.instagram.com/radhradkeLucy Cooke: https://www.instagram.com/luckycooke/

Audio:Becca Bressler’s Greatest Hits - Everybody's Got OneThe Shark Inside You Growth

Lateral cuts - Butt Stuff

Signup for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)!

Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today.

Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing radiolab@wnyc.org.

Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Listen and follow along

Transcript

Oh, wait, you're listening.

Okay.

You are listening

to Radio Lab.

Lab.

Radio Lab.

From

WNYC.

Hey, this is Radio Lab.

I'm Molly Webster.

Hi, I feel like

I haven't seen you since like last summer.

I'm sitting in for Lulu and Lectif today.

Since we were in Michigan

with our contributing editor, Heather Radke.

I think that's right.

All right, Heather.

All right.

I'm going to assume you have a story to tell us.

That's right.

That's why we're here.

I have something to tell you.

So a little while back, I had a conversation with one of Radiolab's favorite science writers.

I'm Lucy Cook.

I'm the author of Bitch on the Female of the Species.

I've got a background in zoology.

All right, Lucy.

We do love Lucy.

Yeah.

She's like this globe-trotting tracker of amazing animal stories.

She's been to Panama to meet stoned dwarf sloths.

She went to Sweden to track drunken moose.

All right.

And then a little while back, while she was working on her latest book.

I was delighted to fly to Seattle and meet this population of orcas.

She got wind of a pretty amazing discovery in killer whales.

Yeah, this felt like a really, really important story and one that I found inspirational.

It was a discovery that directly speaks to something that lots of humans are actually going to have to contend with at some point in their lives, including lucy herself and me and you me you molly

okay so yeah so lucy hopped on a plane flew to seattle

and then to get to the patch of the ocean north of seattle where the whales actually live

you get a seaplane you get to feel like you're in a 1970s you know adventure tv series

that's how everybody traveled in the 1970s was by seaplane to go and deal with emergencies you know

But

the actual reason Lucy was there was to get on a boat

with a woman named

Deborah Giles.

So my name's Deborah Giles, Dr.

Deborah Giles, but I just go by my last name, Giles.

Yeah.

I'd written to her offering up my services to join her on her research boat because I'd heard that she went out every day chasing orcas, trying to catch their poo in a net.

That's what I do.

Okay.

Yeah.

My main job is poop collection.

And the reason why is because, as she'll tell you, poop is a gold mine.

Yeah, absolutely.

Apparently, you can learn a lot about whales by looking at their poop.

Everything you can imagine, anything that you can get from a blood sample, you can analyze through the feces.

Hormones, microbes, environmental chemicals.

Yes.

So what they do is they go out in the boat until they spot this group of killer whales.

And then

you do what's called a distant poop follow.

Oh.

And I believe that that is a scientific term.

You form a little polite distance back.

Yeah, everyone needs some privacy.

Exactly, don't want to overcrowd them.

And at some point,

one of Giles' assistants.

A non-human research assistant.

Oh.

Iba the dog.

The former street dog from Sacramento.

Will pick up a scent.

She'll go to the front of the boat, put her snout in the air, stand up on the bow, and then leads them to it.

Does the whale poop float at the surface?

Yes.

We're not talking a solid turd by any means.

It's more of a thick pancake batter.

And then they just lean over the side of the boat with this plastic lab vial on the end of a stick.

And gently break the surface of the water.

And scoop up the poop.

Okay.

So the reason Lucy went to visit Giles and these whales is because the scientists who study them had noticed something odd.

There comes a time when we don't see the females in population giving birth.

When they got to be around like 40 or so, the female whales just stopped having babies, even though they lived to be 70, 80, even like 100 years old.

These females were living this long stretch of their life without having any new calves.

At first, the scientists thought they were having miscarriages, maybe, or there was some kind of pollutant in the water or something that was causing these older females to stop having babies.

But in 2017, Giles and this colleague of hers, Sam Wasser, published published a poop analysis that confirmed a very different hypothesis that people had been considering for a couple decades.

They wrote, and I quote here, the females in the population have undergone reproductive senescence.

Oh, senescence.

Yeah, which was like not a word I knew, but

maybe you know it.

I don't know.

It's like a fancy way of saying that at a certain age, the reproductive system of these whales started to physiologically shut down.

And along with a lot of other observations about the whales and autopsies of beach whales, they were able to like confirm that these whales were

going through menopause.

Okay.

That's my big reveal, Bob.

I guess they maybe would have expected them to go through menopause.

You're not surprised.

You're not surprised.

I don't know.

I'm like...

Well, you kind of should be surprised because

actually, up until they figured this out about the whales, scientists widely believed that menopause was a uniquely human thing.

Really?

Yeah.

It was assumed that human females were the only species that went through it.

Out of like 6,000 some species of mammals, they thought we were the only ones.

So we were just, yeah, we were just freaks.

And freaks, because if you think about it scientifically, menopause is actually very weird.

Like this isn't you.

Is this sort of you saying like this is weird, or do you think scientists are like, yo, this is weird?

I mean, they would probably say it a little bit more fancy.

So, I'm, you know, I would just come.

Well, no, like, it is super weird, right?

It is super weird.

Okay, so this is a scientist.

His name is Kevin.

And I have a long last name.

Langergraver.

Kevin Langergraver.

I'm an associate professor in the School of Human Evolution and Social Change at Arizona State University.

And Kevin says, from an evolutionary point of view, no animal should have have what he calls the substantial post-reproductive lifespan.

Substantial post-reproductive lifespan.

Fun phrase.

Yeah.

I asked him if we could say something more fun and he said no.

No.

Anyway, the point is, it's the living for a long time after you can no longer reproduce.

That's the weird part.

It shouldn't be, because from the perspective of evolution, right?

Evolution favors traits that get more genes into the next generation.

And if you're not having babies, you're not sending your genes into the next generation.

Natural selection takes a pretty dim view of a loss of fertility, and once you stop breeding, you die.

That's the general story.

And is natural selection really that cut and dry that it's if you're not contributing to the genetic pool, you should be out?

Well, of course, natural selection isn't everything, right?

Not every trait you look at in an organism has a functional reason.

But, you know, like the vast majority of mammal species, you end up reproducing until you die, then it's still super weird that a few don't.

Like, think about it this way.

If there were a human woman who could keep having babies for her whole life until she dies, she would genetically at least out-compete the women who can't.

So it sort of seems like there should be some evolutionary genetic reason for the reproductive system to kind of peter out before the human person does.

That is the evolutionary puzzle, right?

So it's not.

Now, one of the the most common things people say when they hear about this is that in humans, this is kind of like a fluke of modern life.

So the idea was

that perhaps human females were living beyond their reproductive shelf life because we were being propped up by regular meals and modern medicine.

So the idea being that in olden times, we used to die around menopause.

And so this long post-reproductive life is just because now we live longer than we used to.

Right.

But it turns out, actually that's not the case.

Which part?

Which part

is not exactly not true.

None of that's true.

Okay.

In ancient times, people also lived to be about 70.

Really?

Yeah.

I just thought it was like the only people who did were like royals who were highly attended to.

No, the light, so there's this interesting thing where like we get these average life expectancy numbers

and the averages take into account the fact that people die before like the age of five because they die in childbirth.

They die of infant diseases.

Oh, it's like a skewed average.

Yeah, exactly.

So if you account for that, you see that many women were in fact living 20, 25 years, 30 years after they could no longer reproduce.

So humans have been going through menopause like for the entire history of humans.

And it's a thing, menopause.

It's a roller coaster.

You know, it's an emotional and physical roller coaster.

And back to Lucy, she says that going into menopause for her was pretty brutal.

I mean, hot sweats and furious moods.

And it's pretty brutal for a lot of women.

But she also says, once it, it's, I was going to say it's icy fingers, but it's anything but icy.

Once it's hot fingers got a hold of me.

She did have in the back of her mind this question, which was, why?

Why was I still alive?

That's a question.

Yeah, it's a pretty intense way to put it.

But the thing about menopause.

You know, I mean, it's, I mean, I know it gets a lot of press now and everybody's allowed to talk about it.

My mother's generation, no one did.

For such a long time, it's been completely ignored by science, by culture.

And probably partly because of that, I do think a lot of women end up feeling invisible or useless.

You know, you were just sort of irrelevant after going, after your period stopped, you know, and you were kind of this sort of, you know, kind of gray puddle of purposelessness, you know.

So, Lucy.

So, when I heard

that killer whales went through menopause, it felt like a chance to ask, what is this time in her life for in a kind of different, more scientific way?

Yeah.

So these are really big questions.

And there are a number of...

So this is a scientist named Darren Croft.

I am professor of animal behavior at the University of Exeter.

He's part of this huge team that's been studying these killer whales for like decades now.

And so there's this incredible, rich amount of data on their behavior and their movements.

And so what the scientists watching these whales day in, day out have seen is that there's a lot of purpose.

And we know that now.

These females have rich social lives.

Lives that could make sense in like a cold, hard, evolutionary logic kind of way.

So for example, Giles and Darren told us about this one particular female killer whale named Granny, who's possibly the most famous wild killer whale in the world.

Granny, she was just an astonishing whale who lived to be at least into her late 80s, possibly as old old as 105.

And according to Darren and Giles, all the way up to the end, she had this zest for life.

Yeah, what does that look like?

Socializing, foraging, breaching, tail slapping.

It does sound zesty.

Yeah.

Living life.

Yeah.

And in particular, the scientists noticed she's actually a killer grandma.

Carried and played with and babysat, brand new babies.

Because the way these groups of killer whales usually work is sons and daughters stay in their mom's household.

So Granny's part of this sort of multi-generational pod.

Yes, our colleagues capture drone imagery of Granny helping to corral a fish towards her great-grandcalf.

When Darren and his colleagues did a study of these killer whales, they found that the whales that had post-menopausal grandmas around, like Granny, whales who aren't having babies of their own anymore.

Right.

Okay.

When those ones were still around, the young had higher chances of survival than the whales who had no grandmas or even had grandmas who were premenopausal.

Does that make sense?

So the grandmas who couldn't have babies anymore were more helpful than the grandmas who were still having babies.

Right.

And this actually gave like a lot of support to an idea that people have been thinking about in terms of humans actually for a while.

The grandmother hypothesis.

I feel like I hear a lot about the grandmother hypothesis, but I'm not even sure I know how it works.

Yeah, right.

But it's basically what we just learned with the whales.

The hypothesis there is what's important is that post-reproductive females play an important role in the survival of their grand offspring.

There's something that makes a lot of sense, I'll just say as a person with a two-year-old child, like makes a lot of sense to me.

Like, you know, like my mother is just like incredibly helpful and useful.

I mean, that's data point of one.

It's not scientific, but we feel how this is like makes some amount of sense to be true.

Yes.

Yeah.

So this hypothesis hypothesis is just like your evolutionary purpose is to be a mom, even if you are no longer being a mom.

Yeah.

I mean, that's kind of the cultural takeaway.

That's like what most of us think of, if you've ever heard of this before.

But when you look at the whales, it goes way beyond that.

Like the older killer whale female, she's actually kind of running the show.

I mean, it was clear that Granny was the one in charge.

The matriarch of all matriarchs.

They play diplomat or keeper of the peace, especially with the younger male whales.

Females, especially post-reproductive females, are intervening in the lives of their adult sons, making sure that they're not roughhousing enough to get injured.

But also, they're like hunter-in-chief, leading the pod to find food to feed everybody.

Granny and her family have basically always exclusively eaten salmon.

But those salmon are really hard to find now because they've been hunted by humans.

But Granny with her 11 pound super intelligent brain, she can remember things from like 25 years ago.

Yeah, you know, 25 years ago at this time of year, there was a bunch of salmon that did go up this random little tributary halfway up the coast.

And the scientists could like literally see this play out as they were watching the whales on these hunts.

Granny would just start slapping her tail on the water and like all the whales would go like, whoop, granny's calling.

We're going to go in the direction that she wants us all to go.

That was something that we used to get to see quite often.

And even after she spent 45 minutes or even an hour trying to catch a fish, you know, continuing, even though she was most assuredly hungry herself, Charles said she would see her bite the fish in half or sometimes even in thirds and have family members come over to grab that fish.

So the postmenopausal female whales, they might not be adding more of their genes to the gene pool.

But they're not sitting around filing their nails and watching daytime soap operas.

They're like totally crucial to the survival of the group.

These orca females are the repositories for ecological wisdom.

They're keeping their hunting community alive.

Does it make you think about your experience as a woman?

I mean, whenever I ask scientists this question, they're like, don't ask this question.

But I guess, did like looking the orca in the eye and thinking about Granny change anything for you?

Do you know?

I probably shouldn't answer this question,

but I will.

I'll give you an honest answer because I did.

I felt incredibly moved by them.

I really did.

I felt very, I was really pleased that I made the effort.

And I went there and I spent time with Dr.

Giles.

And, you know, understanding how evolution had

granted these females these long lives

with such purpose, made me think

differently

about

my loss of fertility.

And

I found the idea that

my value now was in my wisdom and my brain, and the things that I can teach other people

really empowering.

As opposed to feeling like you're a a grey puddle that's, you know, decreasing relevance in the world.

And, you know,

it's the kind of, it's the opposite.

You know, in every way, I was like, be more orca.

Yeah.

Plus the fact that the older females are having tons of sex.

Oh, my God.

I mean, that sounds great.

Right.

I love the idea of like being an orca, but there is something in me that like just sort of fundamentally chafes at the idea that I have to be useful in some way, like whether that's like being a caretaker or being like a hunter-in-chief.

Right.

Like, it's like I always have to prove my worth

if I'm not there to have babies.

I think you'll be kind of happy to hear that,

you know, that's not the only idea that science has about menopause.

When we come back from break, I'm going to tell you about another animal that's, I don't know, I think you might like this one.

Hi, this is Lulu, and this is an ad by BetterHelp.

It can feel like every day, there's a new claim about what will finally bring you mental wellness and harmony.

Cold plunges, yoga, gratitude journals, therapy, pets, all sound great, but how do you actually know what works for you?

Using trusted resources is so important.

And you know what is the most trusted resource for your mental health?

Your own real living and breathing and thinking therapist.

Someone who can help you find your specific path forward.

I, for one, am a lover of cold plunges and a lover of therapy.

It has helped me countless times with setting better boundaries, becoming a better communicator.

Therapy is for anyone.

As the largest online therapy provider in the world, BetterHelp can provide access to mental health professionals with a diverse variety of expertise.

Talk it out with BetterHelp.

It's convenient too.

You can join a session with a therapist at the click of a button, helping you fit therapy into your busy life, and you can switch therapists at any time.

Radiolab listeners get 10% off their first month at betterhelp.com slash Radiolab.

That's better H-E-L-P dot com slash Radiolab.

Radiolab is supported by Capital One.

Banking with Capital One helps you keep more money in your wallet with no fees or minimums on checking accounts and no overdraft fees.

Just ask the Capital One bank guy.

It's pretty much all he talks about in a good way.

He'd also tell you that Radiolab is his favorite podcast, too.

Aw, really?

Thanks, Capital One Bank Guy.

What's in your wallet?

Terms apply.

See capital1.com slash bank, capital One NA, member FDIC.

Radiolab is supported by Mint Mobile.

You know what doesn't belong in your epic summer plans?

Getting burned by your old wireless bill.

While you're planning beach trips, barbecues, and three-day weekends, your wireless bill should be the last thing holding you back.

With Mint, you can get the coverage and speed you're used to for less money.

And for limited time, Mint Mobile is offering three months of unlimited premium wireless service at an affordable rate.

Use your own phone with any Mint Mobile plan and bring your phone number along with all your existing contacts.

This year, skip breaking a sweat and breaking the bank.

Ditch the overpriced wireless plans and get this new customer offer and your three-month unlimited wireless plan at mintmobile.com slash radiolab.

That's mintmobile.com slash radiolab.

Upfront payment of $45 required, equivalent to $15 a month.

limited time new customer offer for first three months only.

Speeds may slow above 35 gigabytes on unlimited plan, taxes and fees extra.

See Mint Mobile for details.

Radio Lab is supported by him

and hers.

If you're someone who values choice in your money, your goals, and your future, then you know how frustrating traditional healthcare can be.

One size fits all treatments, preset dosages, zero flexibility.

It's like trying to budget with a fixed expense you didn't even choose.

But now there's another way with him's and hers.

HIMS and HERS is reimagining healthcare with you in mind.

They offer access to personalized care for weight loss, hair loss, sexual health, and mental health because your goals, your biology, and your lifestyle are anything but average.

There are no membership fees, no surprise fees, just transparent pricing and real care that you can access from anywhere.

Feel like your best self with quality, convenient care through HIMS and HERS.

Search a free online visit today at hims.com/slash radiolab.

That's h-im-s.com/slash radio lab to find your personalized treatment options.

Not available everywhere.

Prescription products require provider consultation.

See website for full details, important safety information, and restrictions.

All right, we're back for the second part of this episode.

Yep.

Okay, so let's recap.

Love a recap.

We're talking about menopause and how it's super weird.

Totally weird.

We thought for a long time we're the only ones who did it.

And then scientists learned about orcas.

Right.

And scientists started watching them and they sort of thought, oh, maybe we're solving this evolutionary puzzle of like why we have menopause.

Of why we have menopause.

But maybe not so much.

So let me unpack that.

So again, this is this guy, Kevin Langergraber.

We're really getting into the weeds here.

One important detail they didn't mention before about Kevin is that every year for the past 25 years, Kevin has spent time living what he calls chimp life.

Working on this thing called the Ngogo Chimpanzee Project.

Which is a long-term study of this one community of chimpanzees.

It's in southwestern Uganda.

Pretty much smack dab in the middle of Kibali National Park.

So picture like huge, huge trees.

And a wide open forest floor.

Like an open park.

Where every single day.

Get up in the morning, have your breakfast and your coffee.

The sun is just starting to come up.

That's when you want to leave and go find the chimps.

And then he spends the rest of his day just watching them.

Basically, you're writing down what they do.

They're grooming, they're hunting, they're eating.

So, kind of right from the beginning of his time there, Kevin started to notice something interesting about the older female chimps.

Okay.

Like Garbo, for example.

She's an old-timey silent movie character.

Yeah, exactly, exactly.

This female who now is about 72 years old.

No way.

72?

That's like my mom's age.

Yeah.

Kevin's actually known Garbo from the very beginning, since she was about 50.

Okay.

At which point she already had adult kids.

But for the last 25 years, he's never seen her have a baby.

But here's the thing: you know, post-reproductive individuals, they exist, you know?

There's always like the occasional old female who doesn't reproduce anymore.

But the thing Kevin wanted to figure out was like, is garbo an anomaly?

Or is this something that's happening to more chimps than just her?

Exactly.

And to get to the bottom of that, he had to collect biological samples.

Okay, back to poop.

No, not poop.

Pee.

Yeah.

Urine.

Urine, urine.

No shade to poop samples, obviously.

Urine collection is actually easier than fecal sample collection because they pee a lot more than they poo.

I don't know about easy, though, because what Kevin has to do is

you get a stick from the forest, picture a stick that's about three feet long and it looks kind of like a Y.

Sort of like a weird pitchfork or something.

And he puts a little plastic bag on the end of the Y.

And then when the chimps are up in a tree, they're peeing down on you, and you stick your stick out, you know, away from you, so that you don't collect too much pee yourself,

you know, on your head and stuff.

And you get the stream of pee to connect with your stick.

And then it fills up that

bag.

This is highbrow science.

Now these pea samples, they're sort of like the whale poop.

They can tell you a lot about what's happening in the bodies of individual chimps, like Garbo, for example.

You're just waiting for Garbo to pee.

And then when she does, you'd better be ready.

So when Kevin analyzed her samples and the samples of the other older female chimps, we found, you know, smoking gun sort of level of science that we rarely get.

Because looking at the levels of reproductive hormones, it was really just easy to tell yep female chimps carbo and these other old females go through menopause yes and i mean like they go through menopause it's very similar to the human experience or at least we think it is kevin was very careful to mention that like i can't speak to hot flashes no

right like i can't speak to some of the physical symptoms or like the emotional swings right but like there's a hormone cessation right right right and that cessation it's pretty similar to the pattern in humans it's like a ramping down, basically.

Wow.

And after that, they just keep on living their lives for decades sometimes, just like humans and just like the whales.

And then there were three.

Yeah, exactly.

Well, sort of.

Actually, when they did all that orca research, they actually found out that there were a handful of other whales that are really similar to orcas that also go through menopause.

So like narwhals.

Narwhals.

Yeah.

But chimps are the third major animal group we know of that experience this long life after menopause.

Is Garbo also scratching her head, asking what life is for after menopause?

No, she's not.

But Kevin definitely is.

Let's think about it.

Okay, so I'm going to like paint you a picture of what Garbo's life is like.

Okay, so before she stopped having babies, she had three sons.

Monk, Richmond, and Hutcherson.

By the way, why don't they name them like Steve or something?

It feels very like old money.

I know, like, who came up with it.

Okay, so Monk and Richmond actually aren't alive anymore, but let's just like imagine a time when they all were alive.

Because like, long story short, a big part of Garbo's day is hanging out with her sons.

She had like, you know, a good relationship with both Hutcherson and Richmond.

What about Monk?

No, Namonk, she hated Monk.

Oh.

Like they didn't even know they were related until they did the genetic testing.

And they were like, oh, I guess she had three sons, not just two.

Scandal.

Yeah.

Dang, Garbo.

Dang, Garbo.

Anyway, so all day, Garbo, Hutcherson, and Richmond would be together.

Richmond and Hutcherson would groom Garbo a lot.

Like kind of running their fingers through her hair and picking out bugs and like scratching her little back.

Love it.

And she would totally bliss out.

Like zone out in this really zen-like stage.

It's like, you know, I'm bald now, but I remember when I used to go to the hairdresser and get my hair cut.

And you could feel like the hairdresser running their hands through your scalp.

I would just zone out.

Also, Richmond and Hutcherson would bring food to Garbo.

You know, share meat with Garbo.

Monkey meat.

Chimps eat monkey meats?

Yeah.

It's a chimp delicacy.

They love a monkey meat.

Okay.

In the movie version of this they would bring it to her on like a silver platter and honor her i mean that's what's happening in my head

so that does that mean she doesn't have to hunt for herself right also

if someone would be aggressive to to garbo often you know richmond and hutcherson would like chase them off you know protecting their mother

and that's it

That's all that Garbo does.

So like kind of notice here what you're not hearing.

No real grandmothering behavior.

So Garbo is not making Christmas cookies for her grandchildren.

No, she's not.

She's not doing anything toward the youth.

Or really towards anyone.

Oh, really?

Okay.

She's not super helpful.

Huh.

God, that's the dream.

I want to be an old lady chimp.

Yeah.

And so, because the grandmother hypothesis doesn't seem to apply to chimps.

Kevin and a bunch of the other scientists started looking into like, what is going on here?

Yeah, the second most prominent hypothesis is called this reproductive conflict hypothesis.

The reproductive conflict hypothesis.

I love that we've gone from like the grandmother hypothesis, which feels so loving, to

reproductive conflict.

Well, bear with me because in some ways it's maybe the opposite or it's maybe not quite what you think it's going to be.

I love that.

I'm go.

Okay, and the theory itself is like a little bit convoluted, but the big idea is that there's a sort of subtle evolutionary calculation hidden in the way chimpanzee females set up their families.

In chimpanzees, males stay in their group for their whole lives.

But the females, the daughters, when they hit puberty, they leave their family group to join another one.

The general reason for this is like avoid inbreeding, right?

Right.

So think of this.

Think of it.

You're a female chimp.

You're born in one group.

Then you hit like 12 or 13.

You've disperse to a new group where you want to start having kids.

When you first get into that new family, you're not related to anybody around you.

You don't share genes with anyone.

But as you have your first kid, let's say you have a male.

Then you have one family member, your son, who does have your genes.

It eventually grows up.

It has its own kids.

Those kids have your genes.

So you're just getting more related to group members.

As you grow into an older female chimp.

Okay.

So now to zoom out a little bit.

Now here's the, why is it called the reproductive conflict hypothesis?

If you look at the larger group that the chimp female is part of, there's a limited amount of resources.

And if you have a kid, that means that some other female in your group can't have a kid.

Yeah, it's just how basic ecology works.

Right.

Reproduction is a zero-sum game.

So there's reproductive conflict between females.

And so if you're this older female chimp and you're looking around, maybe there are like new young females that have just joined your family.

And you're like, who's going to have the next kid?

Me or this young female?

If this young female has this kid, who's she going to have it with?

Well, it could be my son that has the kid with this young female, right?

And my genes could get passed down that way.

So I'm going to get some indirect fitness benefits through this young female's reproduction.

Mm-hmm.

Mm-hmm.

On the other hand.

Can the young female say the same thing about the reproduction of this old female?

No.

She shares no genes with the hypothetical offspring of this old female.

So as the evolutionary math would have it, old females are predicted to sort of seed these reproductive opportunities to the young females and stop reproducing.

Oh.

So it's like Garbo and other older female chimps can contribute to the group and get a benefit themselves just by bowing out and doing their own thing.

Right.

That's cool.

Yeah, that makes sense, right?

Good theory.

Good theory.

But just like the grandmother hypothesis, it's not a perfect fit.

Why, why, why?

Well, apparently, so this gets kind of like mathy and nitpicky, but Kevin says that the benefits of these older females bowing out, they like don't quite make up for the fact that they're like living these long, luxurious post-reproductive lives, like painting their nails and eating monkey meat.

So it like maybe it doesn't quite work.

Okay.

Damn it.

So is Kevin about to swoop in and be like, I've got my own hypothesis.

No, I do not.

Oh, what?

I do not.

Wait, so I'm just left hanging?

Right, right.

And left with the, I don't know, just

the magic and wonder of this world, right?

There's like not a grand universal theory of post-reproductive females.

Okay.

And it's still just like a real open question of why we orcas or chimps live this long post-reproductive life.

Right.

I mean, honestly, there's a part of me that's like, thank God.

Because if we had actually found an answer, it would have felt so prescriptive.

I don't know.

It makes me feel like it would have been kind of sad.

I totally, like, I agree.

I mean, I think it would be kind of limiting.

And I think the thing is, one of the things I've loved about this reporting process of the story isn't really learning the theories, which are kind of confusing in a lot of ways, but actually learning about these specific animals like Granny and Garbo and just imagining their lives.

Like, what do they do during that time?

Yeah.

And I feel like I've gotten to a point in my reporting where I'm much more interested in the what they're doing than the why does this happen, if that makes any sense.

And at some point, I also remembered that there is, of course, that third animal that goes through menopause and has a long post-reproductive life.

Everyone feels good, strong.

Yes.

And so I called up one of them.

Yes.

My name is Caroline Paul, and I'm a writer.

And my expertise is that I am post-menopausal.

I'm 61 years old.

I mean, to be fair, Caroline also wrote an entire book that's basically a study of how women live their lives after menopause.

Called Tough Broad, From Boogie Boarding to wing walking how outdoor adventure improves our lives as we age and so i went to her and i asked her like okay there's granny there's garbo now tell me about caroline i love that you know i think when i was young i was really interested in metrics so i wanted to be the first she's specifically this like very adventurey kind of lady sometimes i was the first down a river i was the first to mountain bike through the bolivian andes i'm like heather just got her driver's license yeah i didn't just get it but i am learning how to drive alone on the road So, you know, everyone's in a different moment of their life.

Each their own adventure.

Anyway, back to Caroline.

When she started to have menopause symptoms or really perimenopause symptoms.

It was almost like someone had like killed your dog and given you a weird acid drug at the same time for extended periods.

Like in what sense is that the case?

I was crying all the time and eating at weird hours of the night.

The other thing that kept happening is that I would go to parties and I wouldn't remember anybody's face.

Whoa.

And all of this went on for like, I think it was like four and a half years.

Jeez.

But this all kind of tracked with what she was expecting to happen because she, like kind of all of us, had heard that this time in her life would be pretty brutal.

Right.

The only thing you hear, it feels like, is how dreadful it will be.

Right.

But I just remember around 57, suddenly realizing that I felt really different.

She felt like a lot calmer and clearer.

There was no more sudden crying jags.

I remembered everybody's name, everybody's face.

And that's when she realized, oh, now I'm in menopause.

And for this part of her life, she told me really the only messaging she was getting is what like not to do.

Narrowing life, not opening it up.

Because women, as they get older, are getting told things like.

We have to watch our bones, we have to watch our brain, our cognitive health is on decline.

We're told that as we age, we're losing things.

But beyond that, she kind of didn't have a roadmap.

For menopausal women, women over 50, 60, we don't have a script anymore.

There's a big gray area.

She felt kind of lost.

Meanwhile, men her age, everywhere they look, they have tons of scripts, tons of icons.

I mean, Harrison Ford is still running through tombs.

Tom Cruise is jumping off some high building somewhere.

And she was like, why can't we have that?

So she set out to write this book, which became the quest to understand whether I should have outdoor adventure in my life.

And she met all these different women in their 60s and 70s and 80s that were doing like totally badass stuff.

From base jumping as a grandmother to sea kayaking to BMX bike racing.

These are not women who are worried about bones breaking.

Not at all.

And like, well, that's great.

And I'm all for it.

But, you know, as somebody who's maybe not the most physically adventurous person, I also really appreciated some of the other stories she told me about women who are going on quieter but still very meaningful adventures.

I went bird watching with someone in a wheelchair.

And she talked to this kind of amazing woman who learned how to swim in her 60s.

Oh, cool.

And it was very scary for her, but she still pushed herself to do it.

So what she found was like not just a bunch of role models for her, but she also found that for a lot of these women, instead of closing down their life,

had found new aspects of themselves.

Finding new possibilities for their life.

And they kind of had these new capacities for awe and wonder and bravery that they had never tapped into before.

Yeah, I mean, I think that this is a time of great exploration that we should be grabbing hold of.

There are new permutations and very valuable ones of us as we age.

It's like the minute hypothesis is just to flip the script or something, that no script is the script.

Yeah, right, exactly.

And I wonder if one of the sort of uses of us, if we're going to be that, let's say, scientific about it, is simply to show the younger generation that life is going to get better.

I have seen personally that when young people see how our lives are at this age, I think all that is of great value.

So we don't really have to put a lot of work into that.

We can just go and be our best selves.

We should be sitting in that tree, being fed delectable meats, and doing whatever we want.

Thank you, Heather.

You too, Molly.

Good luck on your on my driving journey?

Not on the driving journey, the menopause journey.

Oh, yeah, right.

Our menopause journey.

You've got some time.

Yeah, maybe we'll be

holding hands and base jumping together.

I don't think so.

Maybe we'll do it.

Let's go bird watching.

Okay.

Heather might not have jumped out of planes, but she has done plenty of stories for us over the years.

And one of them is a very delightful conversation with Lulu and Latif called Butt Stuff.

And it is based on Heather's book called Butts a Backstory.

By the way, Lucy Cook's latest book has a bunch of other stories about the lives of females of many, many different species.

It is well worth checking out.

It is called Bitch.

And when you're done with that, you can just move on over to Tough Broad by Caroline Paul.

It is a book about the outdoors and aging and how those things go together.

Special thanks to Daniel Friedman, Rachel Gross, Sam Wasser, Sam Ellis, and Kate Radke.

This episode was reported by Heather Radke with help from Becca Bressler.

It was produced by Sara Cari and Becca Bressler.

It was also edited by Becca Bressler and fact-checked by Emily Krieger.

I now have to do something on these credits that I don't really want to do, which is actually say goodbye to the Becca Brestler, who you just heard a ton about.

This is Becca's last episode at Radiolab.

You may remember her for her on-air hits about voter profiling and the economics of food delivery systems and that one thing about

the bug bite tool and whether or not it works.

On the inside of the show, we know her for all of that and also her just like crazy fast editing style, style, like her strategy brain, her sharp, sharp, sharp sense of humor, and also her ability to sing Billy Joel

at a level that is unbelievable.

And I hope you all get to hear at some point.

Becca, we love you.

We will miss you.

It's been a really rad eight years.

I can't believe it's been eight years.

And yeah, I can't wait to see what you do next.

All of us can't wait.

We'll miss you.

Bye.

Hi, I'm David and I'm in McMurdo Station Antarctica.

Here are the staff credits.

Radio Lab was created by Jad Abamrad and is edited by Soren Wheeler.

Lulu Miller and Latif Nasser are our co-hosts.

Dylan Keith is our director of sound design.

Our staff includes Simon Adler, Jeremy Bloom, Beka Bresler, W.

Harry Fortuna, David Gable, Uria Paz-Gutierrez, Sindhunanan Sambandam, Matt Kielty, Annie McEwen, Alex Neeson, Sarah Kari, Sarah Sandback, Anissa Bitsa, Arianne Wack, Pat Walters, Molly Webster, and Jessica Young.

With help from Rebecca Rand, our fact-checkers are Diane Kelly, Emily Krieger, Anna Pujol-Mazzini, and Natalie Middleton.

Hi, I'm Aubrey, calling from Salt Lake City, Utah.

Leadership support for Radiolab science programming is provided by the Simons Foundation and the John Templeton Foundation.

Foundational support for Radiolab was provided by the Alfred P.

Sloan Foundation.

Radio Lab is supported by Capital One.

Banking with Capital One helps you keep more money in your wallet with no fees or minimums on checking accounts and no overdraft fees.

Just ask the Capital One Bank Guy.

It's pretty much all he talks about in a good way.

He'd also tell you that Radio Lab is his favorite podcast, too.

Aw, really?

Thanks, Capital One Bank guy.

What's in your wallet?

Terms apply.

See capital One.com/slash bank, Capital One NA, member FDIC.

NYC Now delivers the most up-to-date local news from WNYC and Gothamist every morning, midday, and evening.

With three updates a day, listeners get breaking news, top headlines, and in-depth coverage from across New York City.

By sponsoring programming like NYC Now, you'll reach our community of dedicated listeners with premium messaging and an uncluttered audio experience.

Visit sponsorship.wnyc.org to get in touch and find out more.