Robert: Are we about to do classes?
Jad: Yes, we are. Three, two, one. Hey, I'm Jad Abumrad.
Robert: I'm Robert Krulwich.
Jad: This is Radiolab. Today, we're talking about change really, or what looks like change.
Robert: You remember back to the baboons when we started this program?
Robert: The question we were asking them was, will those baboons, if they do enough generations, will they create a new culture?
Jad: Will it stick? Let's hope.
Robert: Let's hope, but we don't know. 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: [chuckles] Exactly. 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. To do that, we need an evolutionary biologist, and we found one at Duke University.
Speaker 1 Can you guys talk to each other now?
Brian: Yes. Hello, hello?
Jad: Who's this?
Robert: That's Brian Hare.
Robert: The first thing Brian Hare did was tell me about another guy.
Brian: Dmitry Belyaev.
Robert: Named, Dmitry Belyaev.
Brian: Dmitry Belyaev was a very famous geneticist in Russia. He was alive during World War II and doing genetics work.
Robert: After World War Two, he was in a little spot of trouble.
Jad: What did he do?
Robert: Well, because he was a real Darwinian, he believed in evolution and genetics.
Brian: 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: It was a death sentence. The writing was on the wall, and he knew that he should probably take the Trans-Siberian railroad from Moscow.
Brian: Quickly, and he went to Novosibirsk. 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: What is Mr. Belyaev actually doing?
Brian: 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.
Jad: You just-
Robert: Think about a wild animal. It is impulsive, it is aggressive, it growls.
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.
Speaker 2: Good boy. Come here.
Robert: The nature of the animal has completely changed here. If you want to learn something about the nature of a creature, how it can change-
Brian: Domesticated animals are a wonderful place to start.
Brian: He decided, "Why don't I just experimentally domesticate some animals?" His cover was that he was going to make better fur coats.
Jad: When was this, by the way?
Robert: Sputnik was up, Russians were feeling good and he was making fur coats, so to speak.
Brian: So to speak, began one of the most exciting experiments in biology.
Robert: Here's what Dimitri Belayev does, he goes to a bunch of fox farmers, he says, "I want to buy a bunch of foxes."
Brian: He says, "Well, all I got to do is take this group of foxes and break them into two groups. One group, I'm not going to change them in any way." It's like a control line.
Jad: One group is just normal fox?
Brian: Normal, but, "The other line, I'm going to decide who is going to be allowed to breed and who is, unfortunately, going to be a fur coat."
Robert: Some of the foxes get to have puppy foxes of their own, and some foxes become fur.
Brian: What he did in the test was marvelously simple.
Robert: He would go or one of his assistants would approach a cage-
Brian: Where the Fox was kept.
Robert: With a little baby fox.
Brian: A juvenile fox. The experimenter would stand, say, a foot away and would just try to touch the fox.
Robert: "Hi little fox."
Jad: Run fox, run.
Robert: If the fox would make this kind of sound-
Brian: And cower in the corner, like most boxing would do-
Jad: What is that, what's that sound?
Robert: That is the sound a fox makes when it's frightened?
Robert: Yes. Frightened fox sound.
Jad: What happens if it makes that sound?
Brian: Well, they did not breed that fox in the next generation.
Robert: To put it another way, they kill them.
Brian: Pretty much.
Jad: That's just wrong.
Robert: Now every so often, maybe one out of every 20 foxes, there would be a fox that would not run back, would not-
Jad: It wasn't afraid, then?
Brian: Then they would choose that fox to breed in the next generation.
Robert: They did this over and over again, generation after generation. they would breed the nice foxes together, get rid of the bad foxes, breed the next set, get rid of the bad foxes. Breed the next set, next set, next set, next set, next set.
Jad: All right. What happened in the end?
Robert: Well, eventually-
Brian: 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 like-
Robert: How many years?
Jad: -exterminating breeding.
Robert: Yes, the breeding technique.
Jad: I would think a long, long time.
Robert: How long?
Jad: How many years you mean?
Robert: How many years?
Jad: It took wolves thousands of years to become dogs. I don't know. A long time.
Robert: Here's the thing, ten years is the answer.
Robert: Ten years.
Robert: It took just ten years.
Jad: Shut up, ten?
Robert: Don't tell me to shut up. I'm telling you, it's ten fox generations.
Jad: Are you serious? Ten years?
Robert: Here's the crazy thing.
Brian: 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: 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: 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: 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: Their bones became very thin.
Jad: Their bones got thinner?
Brian: Yes. 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. I don't know what to make of that.
Robert: It's not over. This experiment has been going on, it's now been 50 years, 45,000 foxes later.
Robert: Brian, by the way, who has read about this said, "I got to see this for myself." He went to Novosibirsk just to check it out.
Brian: I did. I took the Trans-Siberian Railroad, which two days of looking at green grass, and there's one species of tree, and I think there was a butterfly that was pretty.
Robert: Was it birch trees you were looking at? Birch tree, then another birch tree, then another birch tree?
Brian: Pretty much. You got it. I show up and they had thousands of foxes. Giant buildings that are probably as long as a football field full of just rows and rows of foxes. 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. 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: 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: This is the unsatisfactory answer to that problem. Nobody really knows why.
Tecumseh: I'm rolling at my end.
Robert: This is Tecumseh Fitch-
Tecumseh: Here's a synchronized sync.
Robert: -an evolutionary biologist at the University of St Andrews in Scotland, and he has a notion.
Tecumseh: My hypothesis for what's going on here, and this is just a hypothesis-
Robert: Here's what he told me. You got to go back to when a fox is a very, very little itty-bitty thing.
Tecumseh: An embryo.
Robert: Inside its mother's womb.
Tecumseh: 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.
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.
Robert: It needs to grow hormones.
Robert: All of these things that you need as an adult fox-
Tecumseh: All of them come from the same founder population of cells in an embryo.
Robert: Wow. I didn't know that.
Robert: They're called neural crest cells. When the fox grows, these cells-
Tecumseh: 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: Some of them go into the jaw and 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: That's the most important one for our purpose. The adrenal gland pumps out when to be afraid. The adrenal glands say, "Run away, run away."
Jad: That's the thing that makes the fox go, whatever that sound was.
Robert: It's the one that makes that sound. 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: 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: 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 going to complete the deal, the rest of your ear flops over.
Robert: Yes, you haven't completed the task.
Jad: Is that why the dogs have little floppy ears?
Robert: Yes, because their cells have been slowed down to the point where they don't finish the job.
Jad: They are literally arrested.
Tecumseh: 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: 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 thing.
Jad: Wait. 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. Like with the foxes, you just eliminate the meanies.
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?
Richard: Well, when we think about humans, obviously we're getting just super speculative.
Robert: He says if you choose to go back-
Richard: 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: Well, if you look at domesticated animals, they have smaller teeth than their wild ancestors. In humans, we've been getting smaller teeth over the last few tens of thousands of years.
Robert: Just like the foxes.
Richard: 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: It is tempting to think that the same process that's been going on in humans 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. Beyalev shot you if you were too aggressive. Who's domesticating the humans?
Richard: Well, one idea that's 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? Sing songs around the fire camp kids?
Robert: No. I'm talking about communities. If you are in a very small family group, well, then it pays to be big and strong and mean because if you are the biggest guy and you meet a smaller guy and he's got some potatoes and you grab him, eat his potatoes, beat him up, and then move on to the next, you never have to see him again. 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. In this world, if you beat everybody up, you may not survive that.
Tecumseh: When pitted against anybody else one-on-one, the big, strong, mean guy is generally going to 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, "Hey, mean guy, stop it. You're bigger than any one of us, but you can't take both of us or all three of us or our whole group."
Richard: Now, we've got other males in the community who aren't going to go away, and they say, "We go to deal with this guy." Maybe they deal with him by shouting him down, ostracizing him, or even capital punishment.
Robert: 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 of being dead, then we've essentially bred out-
Richard: The more aggressive genes.
Robert: We have domesticated ourselves.
Tecumseh: We're really talking about groups versus individuals here. In a sense, I think we're really talking about the beginning of society and a rule of law in the way that we think of it.
Robert: This pressure to be a little more gentle and to be a little bit more cooperative, this hasn't gone away.
Tecumseh: 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: 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 [unintelligible 00:15:24] 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 it's the only way you survive. We get gentler and gentler and gentler till lambs literally lie down with lions.
Richard: You said it beautifully.
Robert: Do you believe it?
Richard: 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. In the long-term, sure, let's hope that all of us become more-
Richard: More floppy-eared. Exactly.
Richard: With white patches on the ends of our tails.
Robert: Remember when we started working together, how mean I was?
Jad: [laughs] 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.
Jad: Anyhow, we should go to break. Not go to the break, just go to the big break, which is the break that exists between us and everything else.
Robert: let's listen to the way we end it all.
Emma: Hi, this is Emma Jacobs vocalising Videolab station. Videolab is produced by Jad Abumrad. Our staff include Soren Wheeler, Michael Rafael, Owen Horn and Lulu Miller. With help from [unintelligible 00:17:00], Emma Jacobs and Elsa Chang. Special thanks to-
Phil: Phil Hare. I'm Brian Hare's father. To Anne Scott, Anne Heppermann, Dr. Anna Kakova, Dr. Erina Plyena.
Emma And Chris Leeman. Bye.
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