
In today’s podcast, a teaser for our hour-long Sperm show. If you think you learned all there is to know from that junior high school filmstrip, think again.
Loading summary
Jad Abumrad
Introducing Fidelity Trader plus, the next generation of advanced trading from Fidelity. Customize your tools and charts and access them seamlessly across desktop, web and mobile. For faster trades anywhere you go, try the all new Fidelity Trader Plus. Learn more about our most powerful trading platform yet@fidelity.com TraderPlus investing involves risk, including risk of loss. Fidelity Brokerage Services, llc Member NYSE SIPC.
Michaels Shop Announcer
Hey crafters, you're invited to visit the new Knit and Sew shop at Michaels. Find hundreds of fabrics in over 800 stores and over 100,000 styles on michaels.com shop your favorite yarn brands, including Big Twist, caron cakes and Bernat in multiple styles and colors. You'll also find all the machines, tools and notions you need with top brands like Singer Brother and Pellon, plus essential thread and Floss. It's all new at Michaels.
Jad Abumrad
Get ready to shop Lowe's Black Friday Doorbuster deals to save 100 doll $150 on a 30 inch blackstone griddle now $299 plus choose a whirlpool top load washer or Midea top freezer refrigerator for just $398. These limited time door Buster deals go fast, so get holiday ready. Today at Lowe's, we help you save valid 1128 through 12. One selection varies by location while supplies last. See lowe's.com for more details.
Michaels Shop Announcer
You're listening to Radio, the podcast from at Public Radio, Public Radio, WNYC and npr.
Jad Abumrad
Hello, I'm Jad Abumrad.
Robert Krulwich
Hello, I'm Robert Quillworth.
Jad Abumrad
This is Radiolab, the podcast, which means.
Robert Krulwich
It'S not the broadcast.
Jad Abumrad
Not the one hour show.
Robert Krulwich
No, not the one hour show.
Jad Abumrad
This is like a little tidbit.
Robert Krulwich
This is a tidbit, but this is a tidbit with a teasing purpose because we have in the next few weeks we are going to do the real shows about race and there's one about choice. There's one, however, entirely devoted to the subject of sperm. And sperm. You think, well, why would you spend so much time talking about that?
Jad Abumrad
Yes. In fact, it's a very sad, sad, lonely show. Anyhow, go on.
Robert Krulwich
We learn a lot of I mean, if you open up any little basket and ask too many questions, you learn all kinds of fascinating things.
Jad Abumrad
So true. Particularly with sperm.
Robert Krulwich
Yes. So we talked when we were preparing this hour with a woman named Joanna Ellington, a fertility expert who runs a company with a very short name, kind of like Sperm Itself ing I N G it's a fertility firm, and I asked her if you are a healthy male at the very top of your game. So you got everything you're ever going to have, and they're all frisky little guys ready to go. What proportion of your gang would be fit and ready to do the deed?
Joanna Ellington
A normal ejaculate from a man is if you have 14, 1 4, 14% or more of the sperm that are normally shaped. That's a very low percent.
Robert Krulwich
And 86% are abnormally shaped.
Joanna Ellington
Yeah.
Robert Krulwich
How do they differ from the normal?
Joanna Ellington
Typically, you're gonna have problems with the tail. And then that makes it so they can't swim. Right. They swim in a circle, can't swim fast.
Robert Krulwich
Some of them swim in a circle.
Jad Abumrad
Mm.
Robert Krulwich
You mean when they go bang and off you go, they just go round and round and round and round.
Joanna Ellington
Right. And that doesn't work very well, of course.
Robert Krulwich
Okay. Circles, slow. Anything else?
Joanna Ellington
Yeah. As the sperm get ready to be ejaculated, the tail unwinds from around the cell. And sometimes it doesn't unwind. Right. It stays wound up or the very tip of the tail stays kind of in a knot, I guess you could say, basically.
Robert Krulwich
So you got a knot on your tail?
Joanna Ellington
Yeah.
Robert Krulwich
Okay, so we got some stalled out, some going in circles, some going slowly. Are there horror mutant sperm?
Joanna Ellington
Yeah, there's one called Globospermia and that is a very large round head. It's maybe three or four times normal size. And instead of having that oval, it's just quite round looking.
Robert Krulwich
That's like a balloon head. Big fat balloon head.
Joanna Ellington
Yeah, exactly. You can have sperm that have vacuoles, which are basically holes in the DNA. You can have sperm that have two tails. Ooh, yeah.
Robert Krulwich
Isn't that better?
Joanna Ellington
No. You don't want anything abnormal.
Robert Krulwich
Are there double headed ones?
Joanna Ellington
Yes, absolutely.
Robert Krulwich
Are there triple headed ones?
Joanna Ellington
Probably some.
Robert Krulwich
This is making me nervous. Anything else?
Joanna Ellington
Some of them are going to be dead and not moving at all.
Robert Krulwich
Well, that's a problem.
Joanna Ellington
Yeah. In addition to that, there's many, many microbiochemical things that they have to go through. So if you were to actually write down everything that could go wrong with sperm as it goes to meet the eggs, it would be hundreds of little enumerations that could go wrong. But that's why men make sperm all the time. They constantly are making it. They constantly have a fresh supply. You've got to have something that can go through all the hurdles and all the barriers and make sure at the end of the day that you have the best, healthiest sperm cell that's participating in making a baby.
Robert Krulwich
When you Say gad that it's lonely, sad with odds like that. Remember, this is when you're healthiest.
Jad Abumrad
I know.
Robert Krulwich
When you're healthy as well.
Jad Abumrad
What I don't get though is like, how does it, how does it. Well, this is what we're gonna go into the show, but I'll just ask you now, how does it happen, given all of those potential pitfalls and that every sperm is outracing the other sperm as well.
Robert Krulwich
The public image here is that every guy that you put in is, in a Woody Allen movie sense, competing against his neighbor. So it's Jerry versus Ted versus Andy versus Mark versus Freddy versus Billy and they're all rushing to the goal.
Jad Abumrad
And what if Jerry and Ted and Mark and Fer and Billy are all.
Robert Krulwich
Double headed with well, then they don't make it.
Jad Abumrad
So it's. The odds are not in our favor.
Robert Krulwich
But there is a level of cooperation we discovered while doing this hour that was deeply surprising. Sperm are not always about competing against each other. And this we learned from Tim Burkhead, who's a biologist at the University of Sheffield. He told us the story about. It was a wood mouse, a W o o.
Jad Abumrad
Not a could mouse.
Robert Krulwich
Not a could mouse or a should. No, not a should mouse. This is a wood mouse. Yes, wood mouse, which is a gift wood mouse.
Harry Moore
My colleague Harry Moore, who's a sperm biologist here in Sheffield, his cat brought in a wood mouse, laid it on the dining room floor and he looked at it and thought, gosh, that's got large testicles. He dissects it.
Robert Krulwich
Unusual reaction to a cat's gift that I've heard in a long time. I'll say, you know, if you're a testicle guy, you're a testicle guy.
Jad Abumrad
You want to take a closer look?
Robert Krulwich
Anyway, so he dissects the, he dissects the mouse and then carefully removed the sperm inside. And then he looked at the shape of the sperm. This was interesting.
Harry Moore
All rodents, the sperm has a slightly hooked shaped head. But in the wood mouse, that hook is extreme, so much so that the hook bends right back and touches the head again. What Harry noticed was that it looked as though the hook was a specific adaptation to grasp the tails of other sperm.
Robert Krulwich
This sperm on its head was a kind of grasping hook, which suggested that maybe this sperm wanted to, to hold hands with something.
Harry Moore
Harry put the sperm into a kind of special sperm medium. And to his amazement, the sperm all joined up together in what he called sperm trains.
Robert Krulwich
Sperm T R A I N S.
Harry Moore
Yes, like in a railway train. The Tails of other sperm were held by this hook.
Jad Abumrad
And it's just head to tail. Head to tail.
Harry Moore
It looks. It's a bit messy. It's a bit like spaghetti moving forward.
Jad Abumrad
Okay.
Harry Moore
The amazing thing is when he measured the speed at which the sperm trains moved, it was about twice that of isolated sperm.
Robert Krulwich
But wait a second. If me and 700 others of us or 10 of us get together at the head and swim together, our tails all increasing our speed, who gets to be the daddy sperm?
Harry Moore
In the wood mouse, some of the sperm undergo what's called the acrosome reaction, releasing this hook. And when that happens, those sperm can no longer fertilise, but they free a vanguard of sperm that then can fertilize.
Robert Krulwich
And then they give up for their brethren.
Harry Moore
Yeah, that's exactly it.
Robert Krulwich
Whoa. So then it's not fair to say that down there at the sperm level, it's every sperm for himself. In a few cases, the sperm is there for the other guy.
Harry Moore
Yeah, but they're all part of the same ejaculate. All got roughly the same genetic makeup. All those sperm are related, so they all have more or less a common interest.
Jad Abumrad
See, we help each other out.
Robert Krulwich
Yeah, I mean, this is different. However, it is at this point, just specific to the wood mouse. So woodmouse sperm seem to have a thing going on amongst themselves. And the idea that a sperm would sacrifice itself for a brother sperm is very novel when you think about how normally this is thought of as such a competitive event.
Jad Abumrad
That's right. Well, in any case, we hope you'll tune in for that show. It's coming up in about a month and a half.
Robert Krulwich
It's not really a month and a half. If you're listening to this late in the week, it's a month and two weeks from now. Okay, it's a month and two. It's a month. It's so short. It's really five weeks from now going on four weeks, and before you know it, it'll be three weeks.
Jad Abumrad
Do you see what I deal with? Soren, can you take him down, please?
Robert Krulwich
You can't take me down.
Jad Abumrad
Just pot him down, please. Any case, so Visit our website, Radiolab.org, you can find out more about anything on our website. And also, we should say, we should give thanks. We are funded by the Corporation for Public Broadcasting. Hey, take him down. The National Science foundation and the Alfred P. Sloan foundation, who this month is honoring Flash of Genius, the winner of the 2008 feature feature film prize in Science and Technology at the Hamptons International Film Festival. I'm Jad Abumrad. Okay, you can put him back up now.
Robert Krulwich
Albert Krulwich.
Jad Abumrad
We'll see you soon.
Robert Krulwich
Very soon.
Michaels Shop Announcer
Hey crafters. You're invited to visit the new Knit and Sew shop at Michaels. Find hundreds of fabrics in over 800 stores and over 100,000 styles. On michaels.com, shop your favorite yarn brands including Big Twist, Caron Cakes and Bernat in multiple styles and colors. You'll also find all the machines, tools and notions you need with top brands like Singer, Brother and Pellon, plus Essential Thread and Floss. It's all new @Michaels. 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.
Date: October 7, 2008
Hosts: Jad Abumrad, Robert Krulwich
Guests: Joanna Ellington (fertility expert), Tim Birkhead (biologist, University of Sheffield), Harry Moore (sperm biologist)
In this Radiolab "tidbit" episode, hosts Jad Abumrad and Robert Krulwich present a sneak preview of an upcoming full episode dedicated to the science, mystery, and mayhem of sperm. Through conversations with leading experts, the hosts explore the astonishingly complex, competitive, and occasionally cooperative world of sperm—dispelling myths and revealing bizarre true facts about human and animal reproduction. The tone is playful, curious, and often humorous as they journey from human sperm oddities to remarkable discoveries in the animal kingdom.
"A normal ejaculate from a man is if you have 14—one-four—14% or more of the sperm that are normally shaped. That's a very low percent." (Joanna Ellington, 02:50)
"Some of them swim in a circle... some going slowly... some of them are going to be dead and not moving at all." (Joanna Ellington, 03:15-04:32)
"If you were to actually write down everything that could go wrong with sperm... it would be hundreds of little enumerations..." (Joanna Ellington, 04:36)
Notable quote:
"But that's why men make sperm all the time. They constantly are making it. They constantly have a fresh supply." (Joanna Ellington, 04:43)
"The public image here is that every guy that you put in is, in a Woody Allen movie sense, competing against his neighbor." (Robert Krulwich, 05:36)
[05:58] Biologist Tim Birkhead and his colleague Harry Moore become curious after Moore’s cat brings in a wood mouse with "large testicles."
[06:56] Examination reveals:
"The hook bends right back and touches the head again... it looked as though the hook was a specific adaptation to grasp the tails of other sperm." (Harry Moore, 06:56–07:15)
[07:24] Experiment: Placing wood mouse sperm in special medium, Moore observes them forming “sperm trains,” gripping each other head to tail.
"The sperm all joined up together in what he called sperm trains." (Harry Moore, 07:24) "It's a bit like spaghetti moving forward." (Harry Moore, 07:42)
[07:45] Measurement shows these sperm trains move twice as fast as single sperm.
Robert asks, if sperm cooperate, “Who gets to be the daddy sperm?”
[08:08] Moore explains: Some sperm self-sacrifice (undergo the “acrosome reaction,” losing fertilization ability) to free others—allowing a “vanguard” to fertilize the egg.
"They give up for their brethren." (Robert Krulwich, 08:21)
"Yeah, that's exactly it." (Harry Moore, 08:24)
[08:36] The sperm in a train are from the same male and share genetic interests, making sacrifice evolutionarily sensible.
"All those sperm are related, so they all have more or less a common interest." (Harry Moore, 08:36)
"The idea that a sperm would sacrifice itself for a brother sperm is very novel when you think about how normally this is thought of as such a competitive event." (Robert Krulwich, 08:50)
On sperm abnormalities:
"Are there double headed ones?" (Robert Krulwich, 04:22)
"Yes, absolutely." (Joanna Ellington, 04:23)
On the competitive myth:
"So it's Jerry versus Ted versus Andy versus Mark versus Freddy versus Billy and they're all rushing to the goal." (Robert Krulwich, 05:36)
On sperm trains:
"When he measured the speed at which the sperm trains moved, it was about twice that of isolated sperm." (Harry Moore, 07:45)
"They all joined up together in what he called sperm trains." (Harry Moore, 07:24)
On sperm sacrifice:
"Some of the sperm undergo what's called the acrosome reaction... those sperm can no longer fertilise, but they free a vanguard of sperm that then can fertilize." (Harry Moore, 08:08)
"They give up for their brethren." (Robert Krulwich, 08:21)
This Radiolab episode teases the complexity and wonder of sperm biology, upending the classic narrative of ruthless individual competition with surprising tales of cooperation and sacrifice. Through clever storytelling and expert voices, the episode leaves listeners eager for the deeper dive to come.