ROBERT: Are we about to do foxes?

 

JAD: Yes, we are.

 

ROBERT: Okay.

 

JAD: Three, two, one. Hey, I'm Jad Abumrad.

 

ROBERT: I'm Robert Krulwich.

 

JAD: This is Radiolab. And today, we're talking about, well, change, really. Or what looks like change.

 

ROBERT: So you remember back to the baboons when we started this program?

 

JAD: Yeah.

 

ROBERT: The question we were asking then was will those baboons, if they do enough generations, will they create a new culture?

 

JAD: Yeah, will it stick?

 

ROBERT: Will it stick?

 

JAD: Let's hope.

 

ROBERT: Let's hope, but we don't know. And the town that chooses a mayor, is that town expanding the sense of possibility, or is this just a little blip?

 

JAD: Let's hope.

 

ROBERT: Let's hope. Yeah, exactly. But now let's get really serious. There are, indeed, changes that do stick, and we're going to examine a rather startling example of it right now. But to do that, we need an evolutionary biologist, and we found one at Duke University.

 

PRODUCER: Can you guys talk to each other now?

 

BRIAN HARE: Yeah. Hello, hello?

 

JAD: Who's this?

 

ROBERT: That's Brian Hare.

 

BRIAN HARE: That's fantastic.

 

ROBERT: The first thing Brian Hare did was tell me about another guy.

 

BRIAN HARE: Dmitry Belyaev.

 

ROBERT: Named Dmitry Belyaev.

 

BRIAN HARE: And Dmitry Belyaev was a very famous geneticist in Russia. He was alive during World War II, and doing genetics work.

 

ROBERT: But after World War II, he was in a little spot of trouble.

 

JAD: Why? What did he do?

 

ROBERT: Well, because he was a real Darwinian. He believed in evolution and genetics.

 

BRIAN HARE: Thinking about evolution like a Darwinian evolutionist does, that was not popular in Stalin's Russia.

 

ROBERT: Is "popular" the word or was that a death sentence?

 

BRIAN HARE: It was a death sentence. So the writing was on the wall, and he knew that he should probably take the Trans-Siberian railroad from Moscow.

 

ROBERT: Quickly.

 

BRIAN HARE: Quickly! And he went to Novosibirsk. And the way that Dimitry Belyaev decided to hide his continued interest in studying Darwinian evolution was he would begin a fox farm where he would make fur coats.

 

ROBERT: So what is Mr. Belyaev actually doing?

 

BRIAN HARE: What Dr. Belyaev was actually interested in was to understand how does domestication happen?

 

JAD: That's his question? That's a dumb question.

 

ROBERT: No, it's not a dumb question at all, because ...

 

JAD: Well, you just—you bring the ...

 

ROBERT: No, think about a wild animal. It is impulsive, it is aggressive, it growls.

 

[wolf growling]

 

JAD: What is that, a wolf you're playing there?

 

ROBERT: That's a wolf that I've got there in the background. Now this is a domesticated version.

 

WOMAN: Good boy. Good boy! Come here!

 

JAD: Doggy!

 

ROBERT: The nature of the animal has completely changed here. And if you want to learn something about the nature of a creature, how it can change ...

 

BRIAN HARE: Domesticated animals are a wonderful place to start.

 

ROBERT: So Belyaev ...

 

BRIAN HARE: He decided, "Why don't I just experimentally domesticate some animals?" And his cover was that he was going to make better fur coats.

 

JAD: When was this, by the way?

 

BRIAN HARE: 1959.

 

ROBERT: Okay, so Sputnik was up. Russians were feeling good, and he was making fur coats, so to speak.

 

BRIAN HARE: So to speak. Began one of the most exciting experiments in biology.

 

ROBERT: So here's what Dimitri Belyaev does: he goes to a bunch of fox farmers, and he says, "Okay, I want to buy a bunch of foxes."

 

BRIAN HARE: And he says, "Well, all I got to do is take this group of foxes and break them into two groups. And one group, I'm not gonna change them in any way."

 

ROBERT: Okay.

 

BRIAN HARE: So it's like a control line.

 

JAD: So one group is just normal foxes?

 

ROBERT: Normal. But ...

 

BRIAN HARE: "The other line, I'm gonna decide who is going to be allowed to breed and who is, unfortunately, going to be a fur coat."

 

ROBERT: Hmm.

 

ROBERT: So some of the foxes get to have puppy foxes of their own.

 

JAD: Mm-hmm.

 

ROBERT: And some foxes become fur.

 

JAD: Ooh!

 

BRIAN HARE: So what he did—and the test was marvelously simple.

 

ROBERT: He would go, or one of his assistants would approach a cage ...

 

BRIAN HARE: Where the fox was kept.

 

ROBERT: With this little baby fox.

 

BRIAN HARE: Sort of a juvenile fox. The experimenter would stand, say, a foot away, and would just try to touch the fox.

 

ROBERT: Hi, little fox. Hi, little fox!

 

JAD: Run fox, run!

 

ROBERT: If the fox would make this kind of sound ...

 

[fox chirping sound]

 

BRIAN HARE: And sort of cower in the corner, like most foxes would do ...

 

JAD: What is that? What's that sound?

 

ROBERT: That is the sound a fox makes when it's frightened.

 

JAD: Really?

 

ROBERT: Yes. Frightened fox sound.

 

JAD: Huh. So what happens if it makes that sound?

 

BRIAN HARE: Well, they did not breed that fox in the next generation.

 

ROBERT: Or to put it another way, they kill them.

 

BRIAN HARE: That—pretty much, yes.

 

JAD: That's just wrong.

 

ROBERT: But now, every so often, like, maybe one out of every twenty foxes, there would be a fox that would not run back, would not ...

 

[fox chirping sound]

 

JAD: So it wasn't afraid then.

 

BRIAN HARE: Then they would choose that fox to breed in the next generation.

 

JAD: Yay!

 

ROBERT: And they did this over and over again, generation after generation. They would breed the nice foxes together.

 

JAD: Yay!

 

ROBERT: Get rid of the bad foxes. Breed the next set.

 

JAD: Yay!

 

ROBERT: Get rid of the bad foxes. Breed the next set.

 

JAD: Yay!

 

ROBERT: Next set.

 

JAD: Yay!

 

ROBERT: Next set.

 

JAD: Yay!

 

ROBERT: Next set.

 

JAD: Yay!

 

ROBERT: Next set.

 

JAD: All right, all right. What happened in the end?

 

ROBERT: Well, eventually ...

 

BRIAN HARE: They had foxes that were attracted to humans.

 

ROBERT: Now Jad, how long do you think it would take to get foxes from being wild, ferocious animals to being animals who would lick your face?

 

JAD: After this kind of like ...

 

ROBERT: How many years?

 

JAD: ... exterminating, breeding technique?

 

ROBERT: Yes, after the breeding technique.

 

JAD: I would think a long, long time. I mean, I would think, like ...

 

ROBERT: How long?

 

JAD: Like, how many years, you mean?

 

ROBERT: How many years? How many years?

 

JAD: Well, it took wolves, like, thousands of years to become dogs. So I don't know. I mean, a long time.

 

ROBERT: Well, here's the thing: 10 years is the answer.

 

JAD: What?

 

ROBERT: 10 years.

 

JAD: No, shut up!

 

ROBERT: It took just ten years.

 

JAD: 10?

 

ROBERT: Don't tell me to shut up. I'm telling you, it's 10 fox generations.

 

JAD: Are you serious? 10 years?

 

ROBERT: But now here's the crazy thing.

 

BRIAN HARE: What was exciting and surprising was that these same foxes, they actually show a whole suite of changes that he did not select for on purpose.

 

JAD: Like, what do you mean?

 

ROBERT: Physical changes. These foxes, as they became more gentle, for some unaccountable reason, their ears, instead of pointing straight up, flipped over.

 

BRIAN HARE: That's right. It was a big accident that they now have floppy ears.

 

ROBERT: The tails on a fox, which on a wild fox, they're straight, now ...

 

BRIAN HARE: They have curly tails. They have multi-colored coats that are no longer just gray.

 

ROBERT: The tips of their paws lose color. The teeth get smaller.

 

BRIAN HARE: And their bones became very thin.

 

JAD: Their bones got thinner?

 

ROBERT: Yes.

 

BRIAN HARE: Yes. So what happens to the skull and the face is it actually becomes more feminine.

 

ROBERT: The whole animal becomes more delicate and more puppy-like.

 

JAD: Wow! That's—I don't know what to make of that.

 

ROBERT: And it's not over. This experiment has been going on, it's now been 50 years, 45,000 foxes later.

 

JAD: 45,000?

 

ROBERT: And Brian, by the way, who has read about this said, "I got to see this for myself." So he went to Novosibirsk just to check it out.

 

BRIAN HARE: I did. I took the Trans-Siberian Railroad, which, you know, two days of looking at green grass, and there's, like, one species of tree, and I think there was a butterfly that was kind of pretty.

 

ROBERT: And was it birch trees you were looking at? Birch tree, then another birch tree, then another birch tree?

 

BRIAN HARE: Pretty much. You got it. You got it. So I show up, and they had thousands of foxes. Giant buildings that are probably, you know, as long as a football field full of just rows and rows of foxes. And when you see them, they actually wag their tail, they whine like a puppy dog. They're cute and cuddly, and they love people, and they don't bite. So it sounds perfect, except for, the one thing I forgot to tell you is when they're yapping and excited to see you, they cannot help but pee for joy.

 

ROBERT: [laughs]

 

ROBERT: As I do whenever I see you.

 

JAD: What I don't understand though, is it makes sense to me that they're getting nicer, because they're breeding them to get nicer, but why is all this other stuff happening to their bodies? What's going on?

 

ROBERT: Well, you know, this is the unsatisfactory answer to that problem: nobody really knows why.

 

JAD: Gah!

 

ROBERT: But ...

 

TECUMSEH FITCH: Okay, I'm rolling at my end.

 

ROBERT: This is Tecumseh Fitch.

 

TECUMSEH FITCH: So here's a synchronize—sync.

 

ROBERT: An evolutionary biologist at the University of St Andrews in Scotland. And he has a notion.

 

TECUMSEH FITCH: My hypothesis for what's going on here, and this is just a hypothesis ...

 

ROBERT: Here's what he told me. He says you gotta go back to when a fox is a very, very little itty-bitty thing ...

 

TECUMSEH FITCH: An embryo.

 

ROBERT: ... inside its mother's womb.

 

TECUMSEH FITCH: Very, very, very early embryo, like two months old.

 

ROBERT: To become a fox that can survive in the world, this little embryo needs to grow strong teeth.

 

JAD: Yup.

 

ROBERT: It has to grow fur.

 

JAD: Need the fur.

 

ROBERT: Has to have bones, strong bones.

 

JAD: Got to have the bones.

 

ROBERT: It needs to grow glands.

 

JAD: Yep.

 

ROBERT: It needs to grow hormones.

 

JAD: Check.

 

ROBERT: And all of these things that you need as an adult fox ...

 

TECUMSEH FITCH: All of them come from the same founder population of cells in an embryo.

 

ROBERT: Wow. I didn't know that.

 

TECUMSEH FITCH: Yeah, yeah.

 

ROBERT: They're called neural crest cells. When the fox grows, these cells ...

 

TECUMSEH FITCH: They're doing these epic migrations. These guys are like pioneers that are moving throughout the body, and blazing these trails all over the place. Some of them go out into the skin.

 

ROBERT: Some of them go up into the cartilage of the fox's ears.

 

TECUMSEH FITCH: Some of them go into the jaw, and they form all these different tissues: teeth, tail, big parts of the nervous system, major parts of the brain.

 

ROBERT: And the adrenal glands.

 

JAD: What's the adrenal gland?

 

ROBERT: Well, that's the most important one for our purpose. The adrenal gland pumps out when to be afraid.

 

JAD: Ah!

 

ROBERT: The adrenal glands say, "Run away! Run away! Run away!"

 

JAD: That's the thing that makes the fox go ...

 

[fox chirping sound]

 

JAD: Whatever that sound was?

 

ROBERT: It's the one that makes that sound. So when you're breeding fear out of an animal, maybe what you're doing is you're slowing down the migrations of these cells. They don't deliver the fear, and then they don't deliver all the other things that they usually do.

 

TECUMSEH FITCH: What you're focusing on, what you as the experimenter are doing is saying, "I want the guys whose adrenal glands don't mature quickly." That might have the function of making the animal more tame, but what you're doing as a by-product of that is selecting for guys who don't get as many of those cells into their ears, and don't get as many of those cells into their skin, and don't get as many of those cells into their teeth.

 

ROBERT: So if you get some of the cells you need to make your ears firm and straight but not quite enough, then your ear will go up to a certain point, and since the cells aren't gonna complete the deal, the rest of your ear flops over.

 

JAD: Really?

 

ROBERT: Yeah, you haven't completed the task.

 

JAD: Is that why the dogs have little floppy ears?

 

ROBERT: Yeah, because their cells have been slowed down to the point where they don't finish the job.

 

JAD: Oh, they are literally arrested.

 

BRIAN HARE: Bingo! The argument is that actually when you select against aggression in animals, you're changing the time and the rate of development such that the experimental foxes are actually frozen as juveniles. They actually never really grow up.

 

ROBERT: So then to domesticate a fox, just like to domesticate a wolf into a dog, what you're doing is you're making them permanent puppies. It's a Peter Pan kind of thing.

 

JAD: Wait, wait, wait. So if we wanted to apply this to us, and we wanted to, say, breed a gentler, sleeker, human being, we should just kill the football players? Is that the idea?

 

ROBERT: What do you mean kill the football—you don't have something against football players?

 

JAD: No. Actually, I like football. But I mean, like, with the foxes, you just eliminate the meanies.

 

ROBERT: Oh, the meanies. Yes.

 

JAD: Would the same thing happen to us?

 

ROBERT: That's where it gets really interesting. Remember the professor we interviewed a few hours back, Richard Wrangham?

 

JAD: Vividly.

 

RICHARD WRANGHAM: Well, when we think about humans, obviously we're getting just super speculative. But ...

 

ROBERT: He says if you choose to go back ...

 

RICHARD WRANGHAM: If we go back just 30,000, 50,000 years.

 

ROBERT: ... and you look at the collection of skulls, and the early versions of us from way back then, you see some interesting fox-like changes.

 

RICHARD WRANGHAM: Well, if you look at domesticated animals, they have smaller teeth than their wild ancestors. And in humans, we've been getting smaller teeth over the last few tens of thousands of years.

 

ROBERT: Just like the foxes.

 

RICHARD WRANGHAM: We've been getting more gracile bones. That means to say that for a particular length of limb bone, it becomes a little bit narrower.

 

ROBERT: Just like the foxes.

 

RICHARD WRANGHAM: So it is tempting to think that the same kind of process has been going on in humans as has been going on in domesticated animals, which is that there's a natural selection in favor of a kinder, gentler human.

 

ROBERT: Wait a second, though. Who's doing the selecting? In the case of the foxes, Mr. Belyaev shot you if you were too aggressive. Who's selecting the—who's domesticating the humans?

 

RICHARD WRANGHAM: Well, one idea that has been specifically suggested is that it was the growing tendency for our hunter-gatherer ancestors to settle down in stable camps.

 

JAD: You mean like summer camps? Like, sing songs around the fire kind of camps?

 

ROBERT: No. I'm talking about communities. Look, if you are in a very small family group, well, then it pays to be big and strong and mean because if you're the biggest guy and you meet a smaller guy and he's got some potatoes, you grab him, eat his potatoes, beat him up.

 

JAD: Yeah!

 

ROBERT: And then move on to the next, and you never have to see him again. But let's say that as time passes, human society grows a little bit. You form camps. You might have 30 or 40 people. That way you can build bigger fires, and you can catch more bunnies, and you can defend against enemies. But in this world, if you beat everybody up, you may not survive that.

 

TECUMSEH FITCH: When pitted against anybody else one-on-one, the big, strong, mean guy is generally gonna win. When big, strong, mean doesn't win—and we see this in some primates—is when you can start to form coalitions. When you can start to have multiple individuals who say ...

 

JAD: "Hey, mean guy, stop it!"

 

TECUMSEH FITCH: "Yeah, you're bigger than any one of us, but you can't take on both of us or all three of us or our whole group."

 

RICHARD WRANGHAM: Now we've got other males in the community who aren't going to go away, and they say, "Okay, we got to deal with this guy." And maybe they deal with him by shouting him down, ostracizing him, or even capital punishment.

 

ROBERT: And Richard Wrangham's theory is that if that happens enough times to enough bullies who then can't have kids and spread their genes because they have the unfortunate condition of being dead, then we've essentially bred out ...

 

RICHARD WRANGHAM: The more aggressive genes.

 

ROBERT: Or we have domesticated ourselves.

 

TECUMSEH FITCH: We're really talking about groups versus individuals here. And so in a sense, I think we're really talking about the beginning of society, and a kind of rule of law in the way that we think of it today.

 

ROBERT: And this pressure to be a little more gentle and to be a little bit more cooperative, this hasn't gone away.

 

TECUMSEH FITCH: I think if anything, we're being selected to work together more, to be able to tolerate being packed in even tighter. If you put 20 chimps on a jet plane and try to send them across the Atlantic, let me tell you that only one or two would walk off that plane alive. We do this all the time. We take it for granted as human beings that big groups of people can get along with one another.

 

RICHARD WRANGHAM: I do think that it's reasonable to imagine that humans have a future of increasing self-domestication.

 

ROBERT: What I sense you proposing is that as the Earth gets more crowded, all the creatures on earth, or at least sentient creatures, have to start learning to live with each other a little more because they keep bumping into each other. The winners will be the domesticated ones. Everyone will get more empathetic to each other because that's the only way you survive. And we get gentler and gentler and gentler 'til lambs literally lie down with lions.

 

RICHARD WRANGHAM: You said it beautifully.

 

ROBERT: But do you believe it? [laughs]

 

RICHARD WRANGHAM: [laughs] Well, we may have to go through one or two ups and downs before we get there. And of course, there's something slightly alarming about the fact that one possible mechanism by which domestication has happened in humans is through literally execution of the more aggressive types. But in the long-term, sure, let's hope that all of us become more ...

 

JAD: Floppy-eared?

 

RICHARD WRANGHAM: More floppy-eared. Exactly. [laughs] Little white patches on the ends of our tails.

 

ROBERT: Remember when we started working together and how mean I was?

 

JAD: [laughs] You have—oh, my God, we've domesticated you.

 

ROBERT: Yes, you have domesticated me.

 

JAD: I have noticed your ears have been looking a little different recently. Show me your teeth. Smile? [laughs]

 

JAD: Anyhow, we should go to break. Or not go to the break, just go to the big break, which is the break that exists between us and everything else.

 

ROBERT: Yes, let's listen to the way we end it all.

 

JAD: Bye!

 

[EMMA JACOBS: Hi, this is Emma Jacobs, outgoing Radiolab intern. Radiolab is produced by Jad Abumrad. Our staff include Soren Wheeler, Michael Raphael, Ellen Horne and Lulu Miller. With help from Adina Ryan, Emma Jacobs and Ailsa Chang. Special thanks to ...]

 

[PHIL HARE: Phil Hare. I'm Brian Hare's father. ... to Aaron Scott, Anne Heppermann, Dr. Anna Kakova, Dr. Erina Plyena.]

 

[EMMA: And Chris Leeman. Bye!]

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