IRA FLATOW: My next guest, primatologist Frans de Waal has spent his lifetime studying the lives of animals, especially our closest cousins, the chimpanzees. He has observed their shifting alliances, their political ranks. He seen bitter conflicts break out, broken up by peaceful, respected mediators, and he’s witnessed them grieve for and attempt to comfort their dead and dying. 

But one of the most touching stories in his new book, Mama’s Last Hug, is the story he tells of a female chimp who didn’t produce enough milk to feed her young. When Frans taught her to feed her baby with a bottle instead, she repaid him with what most of us would recognize as gratitude, holding both of his hands and whimpering sadly if he tried to leave. 

It’s just one of the many fascinating stories of animal emotions he writes about in his new book. And it might leave you wondering, like me, how unique we, humans, really are. 

Frans de Waal is a primatologist and professor at Emory University in Atlanta. His new book is Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves. And you can read an excerpt at sciencefriday.com/lasthug. And you can also call us if you have a question, 844-724-8255, 844-724-8255. You can also tweet us @scifri. Good to see you. 

FRANS DE WAAL: Hi. 

IRA FLATOW: I think last time we talked, I was on the other end of a phone and didn’t get to see– 

FRANS DE WAAL: I’m not sure. Yeah. I’m not sure anymore. 

[LAUGHTER] 

IRA FLATOW: Let’s talk about Mama’s Last Hug. Who was Mama? 

FRANS DE WAAL: Mama was the alpha female of a very large chimpanzee colony at the Arnhem zoo in the Netherlands who I had known for 40 years, a very central figure. She was not physically dominant over the males, but she was certainly more powerful than most males in terms of her political connections, and her skills of bringing parties together, and so on. 

And Mama’s Last Hug refers to her encounter with my professor, Jan van Hooff, who’s 80 now who went into her night cage to say goodbye when she was dying. And so she embraced him. 

She actually calmed him down because I think he was a bit nervous going in there. We never normally would go in with an adult chimpanzee. So he was a bit nervous, and I think she calmed him down, which was typical of her kind of behavior. 

IRA FLATOW: So what was that last hug like? You describe it in your book. 

FRANS DE WAAL: Well, she embraced him and then tapped him on the back of his neck and his shoulders. And she had a big smile on her face. And she made some sounds. 

And actually people were, first of all, very moved by that encounter because it has been seen, I think, by two million people on the internet. So they were very moved, and I can understand that. 

But people were also very surprised. And that surprised me, is why are people so surprised that a chimpanzee may express emotions in a very similar way, similar gestures, similar face, as we do? Because chimpanzees are our closest relatives, so of course, everything they do is extremely similar to what we do. And so I felt I needed to explain about facial expressions and about sounds that chimpanzees make. And so I took that as the starting point. 

IRA FLATOW: Yeah. And you verified for everybody who has a pet that animals really do have emotions. 

FRANS DE WAAL: Well, that’s interesting that you say that, because the pet owners usually they– as soon as you say, do animals have emotions, they say my dog– and they go on and on. But in science, we have been extremely reluctant, unfortunately. 

I think we went through a very dark period in the previous century where a group of scientists, the behaviorists we call them, had decided that the inner lives of animals, but also actually humans, the inner lives were irrelevant. 

So for humans, for example, it’s only in the 1960s that we started to talk about the intelligence, and emotional states, and so on. And in animals, for sure, there was an enormous taboo that we lived under. And so I learned, as a student, that you shouldn’t be talking about emotions. It’s a word that you should not even mention. 

IRA FLATOW: Yeah. In other words, if you saw a facial gesture, it was not an animal smiling. You would just describe it as how the muscles moved, right? 

FRANS DE WAAL: Yeah. Yeah. So if you take, let’s say, a chimpanzee and a chimpanzee laughs, which they do. They have laughing sounds, like [LAUGHING] type sounds. They would say, why don’t you call it vocalized panting? So they would look for words that make the connection with humans obscure, 

IRA FLATOW: Mhm. You write in the book that some psychologists have argued that the emotions we feel must be more nuanced than those of the animals because we have language to describe 12 different shades of anger, for example. 

FRANS DE WAAL: Hm. 

IRA FLATOW: There’s pleasure, fury, resentment, just to name a few. What’s wrong with that? 

FRANS DE WAAL: That’s based on the idea that language is at the root of things, and I don’t think– I think language is a very late appearing phenomenon in our species and also in the development. You wouldn’t say that a child who cannot speak has no emotions. 

So language is sort of irrelevant. Language is something we use to describe our feelings and to talk about them. And I can explain to you why I took a certain decision and how my emotions figured into that. So language is very good to talk about emotions, but are not at the roots of the emotions. 

IRA FLATOW: 844-724-8255 is our number if you’d like to join in the discussion with Frans de Waal, author of Mama’s Last Hug on Science Friday from WNYC Studios. 

What’s been the reaction to you talking– I mean, this is one of your main themes and it’s been for awhile that animals have emotions. And you talk about in the book about tickling a rat on its tummy, and it’s really laughing. 

FRANS DE WAAL: Yeah, Yeah, Yeah. 

IRA FLATOW: And all these different animals, horses and things like that. 

FRANS DE WAAL: Well, the reaction is, of course, of the general public is, obviously. 

IRA FLATOW: Yeah. 

FRANS DE WAAL: They don’t assume emotions in animals, even though the animals that we eat, they often don’t talk about. But anyway, the animals that we keep, they would say. But in science, of course, there has been an extreme reluctance. 

And even though I have always worked on, let’s say, conflict resolution and reconciliation and that kind of things, or empathy, where emotions clearly play a role, even there, the word emotion is often not used for animals because we– I think we confuse emotions with feelings and people wanted to stay away from that. 

IRA FLATOW: And you write some really– an interesting section about Charles Darwin’s book called The Expression of the Emotions in Man and Animals. And you write, it’s the only major book by Darwin that after its initial success was promptly forgotten. 

FRANS DE WAAL: Yeah, because it was taboo, because he had talked about frisky cows and how they looked happy when they were released in the spring. And this was considered so unscientific that that book was forgotten. 

IRA FLATOW: And has it come back? Has it been resurrected? 

FRANS DE WAAL: Oh, yeah. I think so. It has come back with the words of Paul Ekman. When he started working on the facial expressions of humans, it came back. And now in animal research also, it’s back, I think. 

IRA FLATOW: How important was Konrad Lorenz back in the ’60s? 

FRANS DE WAAL: Yeah. Lorenz was quite a bit more open than the behaviorists about this kind of issues. And he kept a lot of animals and talked very freely. And he wrote beautifully about him. 

I think he was very much focused on aggressive behavior, and that was a bit of a problem. Because after World War II, everyone was focused on aggression for obvious reasons. 

And so a lot of the research started to zoom in on these negative sides of animals. And so we got an enormous amount of research on aggression. But anything affectionate, like if you talk about empathy, or bonding, or love even between animals, was really not accepted. 

IRA FLATOW: He discovered bonding, didn’t he, with birds? 

FRANS DE WAAL: He did, the imprinting with birds. 

IRA FLATOW: Imprinting. Right. Yeah. You write in the book that you’ve always been fascinated with observing others, even from an early age. So what led you toward primatology? 

FRANS DE WAAL: That’s almost like an accident. 

IRA FLATOW: Yeah? 

FRANS DE WAAL: As a child, I collected all sorts of water animals because Holland is full of water. And so salamanders, fish. I also collected birds, and mice, and frogs, and all that kind of things. And then when I went to the university, I wanted to study animals. 

And I became a biologist. But in my first university that I went to, they only worked with dead animals that you cut open, and I found that extremely boring. So I went to another university where they did animal studies, ethology. And that’s how I rolled into animal behavior. 

And the primate work is almost like an accident. I could have ended up with fish, or with birds, or whatever. I love animals. And so for me, it doesn’t make so much of a difference. But if you want to make comparisons with humans, of course, then the primates are ideal. 

IRA FLATOW: Did you ever bump into Jane Goodall? 

FRANS DE WAAL: Yeah, of course. 

IRA FLATOW: Yeah. Yeah. She’s very much out there in the field looking at this kind of stuff also. We’re going to take a break and come back and talk lots more with Frans de Waal, primatologist at Emory and author of Mama’s Last Hug, a very well-written– it’s almost like a personal– 

FRANS DE WAAL: Mhm. 

IRA FLATOW: But it’s more than just about apes and chimps. It’s about other animals. 

FRANS DE WAAL: Yeah. Yeah. I tried to cover many. 

IRA FLATOW: 844-724-8255 is our number. You can also tweet us @scifri. We’re going to take a quick break and be right back with Frans de Waal. Stay with us. 

I’m Ira Flatow. This is Science Friday with my guest, primatologist Frans de Waal, author of the new book, Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves. Our number, 844-724-8255. You can also tweet us @scifri. Lots of people want to talk about it. Let’s go to the phones. Let’s go to Grania in Houston. Hi. Welcome to Science Friday. 

GRANIA (ON PHONE): Hi, Ira. Thanks so much for taking my call. 

IRA FLATOW: Go ahead 

GRANIA (ON PHONE): And– thank you. And it’s wonderful to hear you, Dr. Waal. I’ve enjoyed your work over the years, and I look forward to reading the new book. I just call, as a behaviorist, perhaps to offer a correction or clarification. 

I don’t think it’s true to say that behavior has said that emotion is irrelevant. I think throughout the history of behaviorism, we said that emotion, as an internal experience, is difficult to study scientifically. 

But as we have improved our methodology and have developed ways of studying it, we’ve been able to study it. But we’ve never said it was irrelevant. And as a field that’s often misunderstood, I just felt like I’d like to get that clarification out there. 

FRANS DE WAAL: OK. Well, Skinner has literally said emotions were irrelevant to human behavior. But apart from that, I should say emotions can be studied objectively. 

The feelings behind the emotions, certainly for animals, I have no access to feelings. And so I can guess at feelings, and I assume that the feelings, or the experiences, the inner experiences, so to speak, of a chimpanzee are probably similar to ours. But I have no way of knowing that for sure. 

But I should also say for humans, I have trouble getting at the experience. So for example, Ira can tell me that he was sad at a funeral, but I still don’t know if he felt the same way as I feel when I’m sad. So feelings remain largely inaccessible. But the emotions are expressed in the body, in the face, in the voice, in the sweat, in the breathing and the heart rate. And so the emotions are always expressed in the body, and the emotions are perfectly measurable. 

GRANIA (ON PHONE): Mhm. 

IRA FLATOW: All right. Thanks for your call. You go through so many different emotions. I mean, you talk about bereavement. You talk about funerals that the chimps have for each other. 

FRANS DE WAAL: Mhm. 

IRA FLATOW: I mean, tell us about some of the more interesting ones that you’ve discovered. 

FRANS DE WAAL: Yes. So one of the emotions I went through is disgust, because psychologists have recently declared disgust a uniquely human emotion, maybe based on moral disgust, when we are disgusted by the behavior, let’s say, by people who get the kids into schools by illegal means, for example. 

[LAUGHTER] 

So we are disgusted by those kind of things. And so they have declared disgust uniquely human. But disgust a very old emotion that serves to keep contaminants and parasites out of your body. And we see it in many species. 

IRA FLATOW: Give a– how does it manifest itself? 

FRANS DE WAAL: So for example, dogs, often said to be lacking in disgust because they lick their testicles and they eat feces and stuff like that, and people use them as an example. 

But dogs are very disgusted by citrus, for example. If you cut open a lemon and you hold it– you shouldn’t feed it to your dog, because it’s actually poisonous to them. But you hold it in front of them, they will show a full blown disgust response. 

IRA FLATOW: They will? 

FRANS DE WAAL: They will. 

IRA FLATOW: And what does that manifest as? 

FRANS DE WAAL: They actually flip his tongue and they shake their head, as if they’re shaking something out of their mouths. Chimpanzees, in disgust displays, they have a face very similar to the human disgust face, where we curl up the lip and bring the lip close– the upper lip close to the nose. 

IRA FLATOW: Mhm. You write in your book that despite her age in Mama, who is the topic of the book, became the most sought after female of the group. And you quote– to quote you in the book, “the biggest sex bomb of the chimps.” 

[LAUGHTER] 

FRANS DE WAAL: Yeah, that’s sort of amusing with chimps, is that the older females are actually sexually more attractive to the males than the younger ones. People are always surprised by that. So 

Mama, when she was maybe 40 or something, so an older female already, if she sported one of these genital swellings, the males would go crazy and they would not eat for days and go after her. Whereas if an adolescent female was like that, they would totally ignore her. So the males in chimpanzees, they go for the older ones. 

IRA FLATOW: And you talk about the genital swellings, which don’t look attractive to we humans. 

FRANS DE WAAL: No. 

IRA FLATOW: You compare them to what would look attractive to humans. 

FRANS DE WAAL: Well, humans, cleavage and breasts– men fall for breasts. And so, I always meet people who say, how can the chimps like these big pink behinds. But at the same time, they’re staring at cleavage, and I don’t think that’s so terribly different. 

IRA FLATOW: And you also talk about chimps caring for each other when they’re ill, and they bring blankets for the dead. And who would have thought that? You would have. 

FRANS DE WAAL: Yeah. Yeah. So we had a male at [INAUDIBLE] who was dying. And we kept him apart, and we kept the door a little bit open so that the others could access him. And he was in a very bad shape. And the females would actually bring straw to him and shove it behind his back. He was leaning against a wall, the way we do when we go to a hospital and put pillows behind people. 

IRA FLATOW: Mhm. Because you study chimps and you find these emotions and behaviors that other people would not have found, do you think that we are misinterpreting the intelligence and possibly the emotions of Neanderthals? 

FRANS DE WAAL: Oh, I’m sure. The Neanderthals have been downplayed by our species for ages. The Neanderthals must be stupid, and backward, and so on. I think all the evidence that we see is that that’s not the case, that Neanderthals actually had brains slightly larger than our brain. 

IRA FLATOW: Mhm. 

FRANS DE WAAL: And so I think we have totally underestimated the Neanderthals. And we carry also– as you know, we carry 4% of the genes of them. 

IRA FLATOW: Yeah, yeah. Tweet coming in. How about reading horse emotions when working with them? 

FRANS DE WAAL: Yeah. I’m not a horse person, so I know less about horses. But horses have a lot of muscles in their face, and so they have an enormous range of facial expressions. 

They also can move their ears, which we cannot do and chimps cannot do. But the horses have very expressive ears also. And so horse emotions are just as clearly expressed, I think, as in the primates. Yeah. It’s just incredible how many expressions they have. 

IRA FLATOW: Let’s go to the phones to Matt in Binghamton, New York. Hi Matt. 

MATT (ON PHONE): Hi. 

IRA FLATOW: Go ahead. 

MATT (ON PHONE): Hi. Are you there? 

IRA FLATOW: Yes. Go ahead. 

MATT (ON PHONE): Yeah. In Ithaca, New York a couple of years ago, I witnessed a squirrel get hit by a car, and there was a whole bunch of other squirrels. It was in the fall. And I was just amazed by the reaction of the squirrels. They all came back to try to attend– it was like as if a kid got hit in the street. And I just wondered if you had ever seen anything like that before? 

FRANS DE WAAL: Well, many of the mammals, of course, they have attachments. And so maybe this squirrel had certain individuals that were close, like siblings, or parents, or others that were attached to it. 

And they probably also come to inspect what is going on. They may try to help, if that’s a possibility. But they also, I think– there’s an enormous amount of curiosity if one of them dies. And so I’m not sure that what you saw was necessarily grieving or something because I would need to have more details about it, but certainly there’s a curiosity about it. 

IRA FLATOW: You mention in your book how many so-called animalistic things humans do without realizing that we do it. I’ll give you an example, sniffing our hand after we shake hands with somebody. 

[LAUGHTER] 

FRANS DE WAAL: Yeah. They found that on a hidden camera, as they had filmed a lot of people greeting each other. And they found that when people greet someone by shaking hands of the same gender, they tend to bring their hand to their nose. And they’re probably not even aware that they’re sniffing the other one. But they are doing that. 

IRA FLATOW: A tweet coming in. What research is there regarding the response to music in animals? What, if any, music appears to generate or reflect mood? 

FRANS DE WAAL: Well, there is research now on that increasingly. For example, whether animals can follow the rhythm of music or follow the rhythm that you, as a human, present them with. And some animals are actually quite good at that, like parrots are good at it and pennipeds, like sea lions, are good at it. 

We also did experiments where we present music to apes and see what they like and what they don’t like. We found, I believe that, that Indian music was really liked by chimpanzees. 

So people do experiments on this. Whether they experience emotions similar to the ones that we experience with music is hard to tell. All we can measure is, do they want to listen to it or not want to listen to it? 

One of the funniest ones was a very old experiment on starlings in a cage which could hop from one perch to another one. And one perch produced Mozart and the other one produced Schoenberg. And the starlings clearly preferred Mozart, as you might expect. 

IRA FLATOW: So you can’t tell if certain music is soothing or if– 

FRANS DE WAAL: No. 

IRA FLATOW: –Certain music is excitatory? 

FRANS DE WAAL: Yeah. Maybe there are ways of telling that apart. But for the moment, we just look at preferences. 

IRA FLATOW: Mhm. All right. Let’s go to the phones to Matthew in Denver. Hi, Matthew. 

MATTHEW (ON PHONE): Hi. 

IRA FLATOW: Hi. Go ahead. 

MATTHEW (ON PHONE): I was wondering, Frans, how you’ve seen the veterinary world change with regards to animal emotions being more accepted and maybe primates used in research. 

FRANS DE WAAL: Well, I think that the veterinary schools, they need to do more on behavior. They very often ignore behavior. There are some– I know some that have behavior classes for the students, but they very often ignore the behavior of animals, and that includes also the emotions and the expression of emotions in animals. And so I think the vet students need to learn a lot more about that. 

As far as primates in research, you know probably that in chimpanzees, that is a sort of ended. Chimpanzees are not really used for biomedical studies anymore. And the other primates that are being kept, like macaques, are still kept in many facilities, I think should all be housed socially. 

My view has always been that you cannot keep these monkeys in single cages, as they often still do. And I don’t know why they still do that because it’s really not necessary. And they can keep them in social groups and they would be so far better than what they do at the moment. 

IRA FLATOW: Hm. Tweet in from Susan, who says, cats have been recognized often as aloof and uninterested in humans. Owners may disagree. Discuss. 

[LAUGHTER] 

FRANS DE WAAL: I happen to be an owner. I’ve had cats all my life, and I think cats are just very variable. There are cats who are loners. Yes, they exist. But there’s also many cats who are very social. 

If you have– like I always used to have four cats. If you move from one room in the house to the other room in the house, all the cats would move to the room where you are, because they– I think they like variation and they like your presence. And actually, cats are much more sociable than people often assume. 

IRA FLATOW: You write that the emotional lives of birds are on par with mammals. Tell us about that. 

FRANS DE WAAL: Yeah. Birds have these very strong attachments. So for example, if you talk about grieving and being affected by the death of a partner, then birds are a prime example because many birds have lifelong bonds between male and female. 

And so if one of them dies– I used to have jackdaws, which is a sort of corvid, sort of a little crow actually. And I had two that were very bonded to each other. And then the female disappeared. She escaped from the [INAUDIBLE]. The male kept calling, and calling, and calling until he died, basically. He didn’t eat, and he died. 

IRA FLATOW: Is that right? 

FRANS DE WAAL: Yeah. 

IRA FLATOW: Yeah. And you also talk about rodent faces were long thought to be unaffected by emotions. But detailed studies show other rodents have no problem recognizing. 

FRANS DE WAAL: No, the rodent literature always emphasized that they have no facial expressions. And now recently, there was a study, for example, in Switzerland that was done where they– it was a funny study. 

They had two classes of rats. One that they tickled, and treated very well, and they sort of made them very happy, and another group that they didn’t do much with. And then they asked an independent judge to judge from the face and the color of the ears what they thought had happened. And they could tell they’re happy rodents apart from the unhappy ones. 

IRA FLATOW: I’m Ira Flatow. This is Science Friday from WNYC Studios, talking with Frans de Waal, author of Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves. In the last few minutes, tell us what the emotions tell us about ourselves. How would you summarize that? 

FRANS DE WAAL: I think we are much more emotional beings than we often say we are. We think we are rational beings and we make all these rational decisions. But I think emotions figure into everything we do. And we also underestimate the animality of our emotions because I don’t think we have emotions that animals don’t have. 

So basically, I look at our emotions like organs. I don’t have any organ in my body that a frog doesn’t have or a rat doesn’t have. I have a liver, and a kidney, and a heart, and brain, and so on. And I think the same is true for our emotions. There are no human emotions in my mind that cannot be traced back to equivalent animal emotions. 

IRA FLATOW: In fact, you talk about in your book that pigs can have an optimistic or pessimistic look, depending on how they’re raised. 

FRANS DE WAAL: Yeah. Yeah. They have done experiments on pigs, because they do these experiments where they have to react to an ambivalent stimulus and see if they’re hoping for food or not hoping for food. 

So you can test the optimism of the pig. And the optimism of the pig depends on how the pig is kept. If the pig is kept in a nice space with a lot of straw and enrichment, the pig is more optimistic than the ones who are kept in a barren place. 

IRA FLATOW: Mhm. So let’s not confuse them we talk about animals what we think animal intelligence is and emotion is, right? 

FRANS DE WAAL: Yeah. I think some animals are maybe not the most intelligent animals, but they are very emotional. But I think all animals, all the mammals for sure, and also all the birds, they have quite an emotionality. 

IRA FLATOW: And do animals have comedy, laughter? 

FRANS DE WAAL: Yeah. I describe some examples of a sense of humor of the great apes. So one example is this was a fellow researcher of mine who put on a panther mask and hid in the bushes away from the chimpanzees. And then all of a sudden, he showed himself. And all the chimps, 25 chimps, they got very angry at him and started throwing stuff at him. 

And he did that multiple times. And then at some point, he took the mask off, showing his own human face. And there many chimps who had this laugh expression that chimpanzees have, as if they thought this was sort of amusing, that he had been tricking them, you know? 

IRA FLATOW: Other animals? Do they also have comedy? 

FRANS DE WAAL: I’m not sure. People describe, always, their dogs. Some dogs seem to have a sense of humor, but I’m not sure about that. 

IRA FLATOW: Mhm. What don’t you know yet that you want to know? 

FRANS DE WAAL: Oh. I want to know more about the feeling side of the emotions. 

IRA FLATOW: Oh. 

FRANS DE WAAL: About how they experience them. So we don’t know that, really. And for the moment– that’s why in my book I am very shy about the feeling part of the emotions. But I think with neuroscience, we may get there. And we can maybe see if the feelings associated with them are similar to ours. 

IRA FLATOW: Hm. When you see neuroscience, you mean probing the brain? 

FRANS DE WAAL: Yeah. 

IRA FLATOW: Yeah? 

FRANS DE WAAL: Yeah. Yeah. Maybe some non-invasive imaging signs that we can do on animals that increasingly is being done on animals. 

IRA FLATOW: Thank you very much for taking the time. Good luck with the book. It’s a great read. Frans de Waal is a primatologist and professor at Emory. And his new book is Mama’s Last Hug: Animal Emotions and What They Tell Us About Ourselves. And we have an excerpt up on our website, sciencefriday.com/lasthug.

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