TED日本語 - フランス・ドゥ・ヴァール: アルファ雄の驚くべき科学

Well, I have known many alpha males in my life, chimpanzee alpha males, and I'm going to talk about what an alpha male is, because I think we can all learn a lot from our close relatives where we have alpha males.

And as an example, I want to give you Amos, a male that I knew who was a young male and he was alpha male, he was very popular, but he got sick and he lost his position because, you know, chimpanzee males they can spot from a mile away if you are weak and they went for him, and he lost his position, and then he got sicker and sicker until at some point we had to isolate him. The group lived on a grassy island, and we had to isolate him in a cage, but we cracked open the cage so that the rest of the chimps still had access to him. And what happened was most touching. Other chimps would bring food to him, they would bring wood wool to him, which is this thing that they use to sleep in and build nests out of, and females would put the wood wool behind his back. He was leaning heavily against the wall, and the way we do with pillows to patients in a hospital, they were putting that stuff behind his back. And I thought, this is the way to go for an alpha male. He was loved and respected, and everyone was taking care of him, and this is not always how it goes, because some males don't end so well when they lose their position.

So Amos was an example of a male who was liked as a leader, and I think the term alpha male, if you look it up on the internet, you will find all these business books that tell you how to be an alpha male, and what they mean is how to beat up others and beat them over the head and let them know that you are boss and don't mess with me and so on. And basically an alpha male for them is a bully. And I really don't like that kind of description, because I am actually partly responsible for the term "alpha male" because I wrote this book "Chimpanzee Politics," which was recommended by Newt Gingrich to freshmen congressmen. I don't know what good it did, but he recommended that book to them, and after that the term "alpha male" became very popular. But I think it is used in a mischaracterization. It's used in a very superficial way that doesn't relate to what a real alpha male is. And so I'm here to explain what that is. The term itself goes back actually much further. It goes back to the '40s and '50s, research on wolves, and basically the definition is very simple. The highest ranking male is the alpha male. The highest ranking female is the alpha female. Every primate group has one alpha male,one alpha female, not more than that, there's only one. And I will explain how that goes.

So first, the body language. What you see here is two male chimpanzees who are the same size, but one is walking upright, has his hair up, has a big rock in his hand, and he's the alpha male. The other male is pant-grunting to him, is being submissive to him and bowing for him, and that is the sort of ritual they need to go through many times a day in order to have a stable relationship. I'll show you a video from the field. What you will see here is a female pant-grunting to an alpha male and you will see how that goes. The male is approaching, she grunts at him.

(Chimpanzee grunts)

He has all his hair up and he displays.

I'm actually standing far too close. A chimpanzee is far stronger than I am, and I just was not very prudent, this particular video.

So what you saw him do is he was lifting himself up and standing on two legs, and putting his arms out. That's called the bipedal swagger. It's a very common posture in high-ranking males, and it's very recognizable because humans do this kind of stuff.

(Laughter)

Humans do this all the time. And what I really like about this particular picture is the two old guys to the side. This is very chimpanzee. In chimpanzees, we have usually old males who are over the hill, who can not be alpha male themselves anymore, but they start playing games and forming coalitions, and behind the backs of others. And they become extremely influential, and you may actually have old males who are more influential than the alpha male himself.

Just as an example, the three males that I used to work with most at the Dutch zoo long ago, where I worked, and the middle male here is a 17-year-old alpha male. The male whom he is grooming on the side is twice as old, and this old male has made him the leader. So you can imagine that that old male has an enormous amount of power, because he has made the alpha male alpha male. The male on the right is individually the strongest male. In captivity, you can test it out, and you can know that this male has no trouble with either one. He has only trouble with the combination of the two. And so the coalition formation that goes on in chimpanzee society makes it much more complex than you think. It means, for example, that the smallest male in a group can be the alpha male. You don't need to be the biggest and strongest male. The smallest male, if he has the right friends and keeps them happy, or he has female support, he can be the alpha male.

So the coalition system makes everything complex, and I'm always waiting here in the US for the primaries, the end of the primaries, because that's a moment where you need to demonstrate unity. Now let me first show you how the unity is shown in chimpanzees. What you see here is two males on the left who are standing together. You also see the big canine teeth that they have. And they're standing together and they demonstrate to the rest of the group, "We are together. We are a unit." The males on the right are walking together in synchrony. That's another way of demonstrating that you are together. And so demonstrating unity is extremely important in a coalition system, and as I said, in the primaries always I'm waiting for that moment because then you have two members of the same party who have been fighting with each other, and they need to come together at some moment. And it leads to very awkward situations. People who don't like each other need to embrace each other and stand together, and that's absolutely essential for the unity of the party, and if you don't do that, the party may fall apart. And so if it doesn't go well, like in this particular case --

(Laughter)

then the party is in deep doo-doo because they have not demonstrated unity. So that's a very important part of the coalition system, and that's something that we share between humans and chimpanzees.

Now, how do you become an alpha male? First of all, you need to be impressive and intimidating and demonstrate your vigor on occasion and show that you are very strong, and there's all sorts of ways of doing that. But other things that you need to do is you need to be generous. So, for example, males who go on a campaign to dethrone the leader, which may take two or three months where they're testing all the coalitions in the group, they also become extremely generous. They share food very easily with everyone. Or they start to tickle the babies of the females. They're normally, male chimpanzees, not particularly interested in infants, but when they are campaigning like that, they get very interested in infants and they tickle them, and they try to curry favor with the females.

(Laughter)

So in humans, of course, I am always intrigued by these men who are candidates and hold babies up like this. This is not particularly something that babies like --

(Laughter)

but since it is a signal to the rest of the world, they need to hold them in the air. And I was really intrigued by, when we had a female candidate in the last election, the way she held babies was more like this, which is what babies really like. But she of course didn't need to send the message that she could hold a baby without dropping it, which was what the man was doing.

So this is a very common tactic, and male chimpanzees, they spend a lot of time currying favor with all sorts of parties when they are campaigning.

Now, what are the privileges and the costs of being an alpha male? The biggest privilege is females. Food is really irrelevant. Male chimpanzees can go a week without food if there's a female in estrus and they're sexually interested in her. Food is secondary to sex. And so the male chimpanzees -- and we evolutionary biologists, of course, we have an explanation for this, is that sex leads to reproduction, and reproductive success is the measure of evolution. That's how everything evolves. And so if males can enhance their reproductive success by being high ranking, you get automatically the ambition to be high ranking in the males. So that's the privilege. The costs,one cost is of course that you need to keep your partners happy. So if you come to power with the support of an old male, you need to let that old male mate with females. If you don't do that, that old male is going to get mad at you, and you're going to lose him as a partner. So there's a transaction going on. If you become alpha male this way, you need to keep your partners happy. And so that's one of the costs.

The second cost is that everyone wants your position. Alpha male position is a very important position, and everyone wants to take it from you, and so you constantly have to watch your back. You have to be extremely vigilant. For example, you have to disrupt the coalitions of others and that's what male chimpanzees do quite a bit. Divide and rule strategies, they have. And so that's a very stressful situation, and we actually have data on this. The data comes from the field, from baboons not chimpanzees in this case, where they did fecal samples on the baboons and they analyzed them for glucocorticoids. And what you see here is a graph where you see that the lower ranking the male baboon is, the higher is his cortisol level in the feces, but the alpha male, as you see, has just as high a level as the lowest-ranking males, and so you may think that being alpha male is nice and dandy and is wonderful, but it's actually a very stressful position, and we can demonstrate that physiologically.

Now, what are the obligations? And here, for me, it gets really interesting, and it deviates very much from your typical image of the alpha male. The alpha male has two sorts of obligations. One is to keep the peace in the group. We call that the control role, to control fights in the group, and the second is to be the most empathic, the consoler in chief, basically, of the nation, so to speak.

So first of all, keeping the peace. This is a male who stops a fight between two females. Two females on the left and the right have been screaming and yelling at each other over food, because food is very important for the females, and so he stops the fight between them and stands between them like this. And it's very interesting to me that alpha males, when they do this, they become impartial. They don't support their mom or their best buddy. No, no, they stop fights, and they come up for the underdog in general. And this makes them extremely popular in the group, because they provide security for the lowest-ranking members of the group. And so they become impartial, which is an unusual condition for a chimpanzee to be in, because they're usually very fond of their friends and so on, and these alpha males who are good at this, they can be very effective at keeping the peace in the group.

And the second thing they do is they show empathy for others. Now, I do an enormous amount of research on empathy, and I don't have time to go into it, but empathy is nowadays a topic that we study in rodents and dogs and elephants and primates, all sorts of animals. And what you see here is two bonobos. The one in front has been beaten up in a fight. The one in the back puts her arms around her and consoles her. This is also actually how we measure empathy in young children, by looking at how they respond to distressed individuals. And high-ranking males, they do a lot of this. High-ranking males provide an enormous amount of comfort in the group, and they go to places where there are earthquakes or hurricanes and they provide comfort. The pope does this. The presidents do this. All the leaders in the world have to do this job. The queen does it and so on. They all have to do this job, so providing consolation, and that's a very important task. And males who are good at these two, keeping the peace and providing comfort, they become extremely popular leaders, and there's actually some self-interest involved in it. They don't do it just for the group, because it also stabilizes their position. The more popular a male becomes as alpha male and the more the rest of them respects them and looks up to them, the better their position is defended in case it's going to be challenged by somebody else, because then, of course, the whole group is going to support that male because they want to keep a leader who is good for them. So the group is usually very supportive of males who are good leaders, and it's not supportive at all of bullies. And when bullies lose their position, they may end up in a very bad situation there.

This is data actually on the consolation behavior. This is data on consolation in chimpanzees, and you see for the medium- and low-ranking individuals, the females do more of it than the males. This is basically the whole community. And this is true for all the mammal studies on empathy is that females have more of it than males. But look at the alpha male. The alpha male does far more than anybody else. And so that's the data on alpha males being the consoler in chief, basically.

The last thing I want to say is something about alpha females. This is a picture of Mama, the alpha female in the Arnhem zoo where I used to work, who is now all over the internet, I think a hundred million clicks at the moment, for a video of her dying at the age of 59, which happened last year. And Mama was an absolute centrum of the group. So she was not physically capable of dominating the males. She ranked below the males, but she was the center of the community, and if there was big trouble in the community, everyone would end up in the arms of Mama. And so she was a very important figure. And so I don't want to minimize the position of alpha females in the chimpanzee group.

And then we have a species that is equally close to us as the chimpanzee, the bonobo. We often forget about the bonobo, but the bonobos have a matriarchal society and the alpha individual is a female, generally. Generally, it's a female who is at the top of the community, and we know much less about how this is done and how they get to that position, and what they do with it, because we know much less about bonobos in general. But I do want to emphasize that the alpha in a group doesn't need to be a male, and that actually in one of our close relatives, it is a female.

So the message I want to leave you with is that if you are looking at men in our society who are the boss of, let's say, a family or a business or Washington or whatever, you call them alpha male, you should not insult chimpanzees by using the wrong label.

(Laughter)

You should not call a bully an alpha male. Someone who is big and strong and intimidates and insults everyone is not necessarily an alpha male. An alpha male has all sorts of qualities, and I have seen bully alpha males in chimpanzees, they do occur, but most of the ones that we have have leadership capacities and are integrated in their community, and, like Amos at the end, they are loved and respected, and so it's a very different situation than you may think.

And I thank you.

(Applause)