MS. SUSAN PAGEThanks for joining us. I'm Susan Page of USA Today sitting in for Diane Rehm. Everyone who has spent time with animals knows they have intelligence, but we have been taught to believe that humans are far smarter. Biologist and primatologist Frans de Waal argues we have vastly underestimated the extent of intelligence possessed by creatures as diverse as octopuses and crows.

MS. SUSAN PAGEHis new book is titled "Are We Smart Enough To Know How Smart Animals Are?" And he joins us by phone from Atlanta. Welcome to "The Diane Rehm Show."

MR. FRANS DE WAALI'm glad to be there.

PAGEWe're glad you're with us by phone. And we invite our listeners to join our conversation. You can call our toll-free number later in this hour, 1-800-433-8850. Send us an email to drshow@wamu.org or find us on Facebook or Twitter. Well, Frans de Waal, you write in your book that this is an area of exploration that's really exploded in the last 25 years or so. Longstanding assumption that animals just weren't as smart as humans. Can you remember when you first thought that was incorrect, that when you noticed an animal exhibiting a level of intelligence that really surprised you?

DE WAALOh, you know, I've worked with chimpanzees even when I was a student and already, at that time, I had my doubts about what was going. And the field of animal studies, people had a very simplistic view of animals. They were either instinct machines, so everything was sort of genetic programmed behavior or they were very simple learners. We put them in a box like -- it's known as the Skinner Box. You put a rat in a box. You have them press a lever and see what they do with that.

DE WAALAnd that was all people did, actually, with animals as far as intelligence was concerned. And even the word animal intelligence or animal cognition could not be used because with animals it was far too simple. And then, I worked with chimpanzees and I saw, of course, that chimpanzees, they reconcile after fights, they use tools in very complex ways. They have political strategies. Actually, in this particular season in the U.S., you see a lot of chimpanzee-like strategies going on.

DE WAALAnd so I felt that the chimps, for sure, were totally underrated, but I think that applied to many other species as well.

PAGEYou know, one of the interesting images you have in your book is that it's a mistake to think of intelligence as being a ladder that you climb and that you can put people on a step and say, I'm a step higher or a step lower. But more like a bush where there are lots of branches that come out in different ways, different kinds of intelligence.

DE WAALYeah. That is actually some -- that is a realization we have now is that as soon as we find something in the apes -- apes are very close to us and very similar to us and so, yes, we usually discover the first signs of cognition in apes, but very soon thereafter, you're going to find it in other groups of animals, like in elephants or in crows or in dolphins or in dogs. And this happened, for example, with tool use.

DE WAALThe apes were very well known for tool use and have very complex ways of doing it and they even make tools so they modify things to make it a better tool and that was all very impressive. But now, we have the crows. And the crow family is apparently very good at using tools and people do complex experiments with them like they get a vertical tube with water in it, there's a floating mealworm in it, but they cannot reach the mealworm. It's too deep into the tube and so the crows, they will throw stones in the tube to raise the water level to get the mealworm within reach.

DE WAALAnd so we're doing that kind of studies now on crows and tool use has, you know, it is octopus using tools. There's crocodiles using tools. There's all sorts of animals now that use tools.

PAGESo for a crow to do that, a crow has to figure out that the water level's too low and if I throw a stone in it, it will raise the water level and raise the food that I want to get at. That's reasonably complex, isn't it?

DE WAALThat is very complex and if you do the same test with chimps and children, it gets even more complex. So what we do with chimps, for example, we give them a vertical tube with a peanut at the bottom and they cannot do anything with it. And they will shake it and they try with their fingers to reach into it. But then, often, some of the apes, not all of them, the smart ones, let's say, they go to the water faucet, they suck up a lot of water and they spit it into the tube until the peanut floats up.

DE WAALAnd sometimes they have to do -- to go to the water faucet five times until it is at the level where they can pick up the peanut. If you do that same experiment with children, I think it's 5 percent of the 4-year-olds who can do it so 95 percent doesn't do it, and there's 50 percent of the 8-yar-olds who do it. And so the chimps are operating -- they're at a level of, let's say, an 8-year-old child and so that's a very complex task.

DE WAALWe even had a female who tried to pee into the tube, which was not entirely successful, I must say, but she had the right idea. And chimps, they can solve a problem that we don't even present the solution. They have to come up entirely by themselves with the solution.

PAGEYou know, you talk about use of tools as being kind of a traditional dividing line when you talk about intelligence. You write about a crow named Betty who actually fashioned a hook out of a straight piece of wire. Now, what was the motivation for her there?

DE WAALYeah. So there is a book by an anthropologist, which is called "Man, The Tool Maker," and it was written in the 1950s and he had decided that the main thing that set our species apart is that not just we use tools, but we make tools. Now, of course, that was already debunked by chimpanzees in all sorts of studies, but now we have Betty in an Oxford laboratory who was given the tube in which there was a little food reward in a bucket, but she was only given a straight wire, a metal wire to get it out.

DE WAALAnd she was incapable of doing that. And she kept trying until one moment, she took out the wire and she started bending it and bending it until she had made a hook out of it and then she could lift up that little bucket with food out of the tube and so she had made a tool, which is interesting because it was once considered the hallmark of human intelligence. And this has happened so many times in my lifetime is that claims have been made about this is what sets us apart, this is the big difference.

DE WAALFor example, humans can plan ahead. Humans have a theory of mind. Humans know what they know and humans recognize themselves in the mirror. They were all these kind of claims going on about what sets humans apart and that's why in this book, I asked to put a moratorium on that because none of these claims has really worked out and most of them have been refuted within years. And so I'm asking people to stop making these claims. It's pretty useless. It's not a contest.

DE WAALWe're trying to understand cognition in humans and animals and it's not a contest. It's not who's the smartest or who's the best. That's not what it is about. It's more about understanding what is going on.

PAGEYour new book is called "Are We Smart Enough To Know How Smart Animals Are?" You know, you've mentioned the use of mirrors and it was -- you said that elephants had failed the mirror test. They didn't recognize themselves in a mirror, but the default was really at the humans who were conducting the test. What was the key?

DE WAALYeah, so with the elephants, they had used the small mirror. Now, elephants is a big animal and so what does it see in a small mirror, probably a lot of gray that moves around and so I don't know why that was done that way, but the elephants had failed the mirror test and people had concluded that means they have no self awareness, which is like a big conclusion out of a little experiment. And so we decided, Josh Plotkin and I, we decided to make a big mirror, an 8 x 8 foot mirror, which at first we did it at the Bronx Zoo, but later we had done it in Thailand with elephants there.

DE WAALAnd some elephants, not all of them, but some elephants passed the mirror test where you put a mark above their eye so at a place that they cannot see without a mirror. We put them in front of the mirror and do they then touch that mark? If they touch the mark with their trunk, that means that they connect to a mirror image with their own body and that's a sign of self awareness, which very few animals pass. So apes can do this, dolphins can do it, humans can do it, but there's very few animals who spontaneously pass the mirror test.

PAGEOn our website is a video of a crow solving a problem so go to drshow.org if you'd like to see that. We've also posted an excerpt from the book. You know, there are two failings or two instincts that you criticize in the book, one is anthropomorphism. Tell us what that is.

DE WAALYeah. Anthropomorphism is the attribution of human-like experiences to animals and this has usually been used as a weapon against any cognitive story. So people usually feel that being anthropomorphic is bad and we need to avoid that and we need to go with the simplest possible explanation that we can find. But if you have an animal like a chimpanzee or a bonobo that is so extremely close to us, we do have to use the same language for what they do than what we do.

DE WAALSo for example, if a chimpanzee kisses another chimpanzee after a fight, which we call a reconciliation, we're not going to go with terminology like post conflict contact or something like that because the chimp is so close -- it's a bit like if you have a horse and a zebra who behave very similarly, of course, you're gonna use the same terminology for the things that they do. And a horse and a zebra are about as close as a human is to a chimpanzee so that's what we're talking about.

DE WAALAnd so I'm arguing in the book that -- and I'm using the word anthropodenial as a counterweight to anthropomorphism. I'm saying we should not deny the connections that exist. We should not, by linguistic means, try to drive a wedge between us and other animals by using this kind of terminology. So for example, another example that I use is if you tickle a chimpanzee, a juvenile chimp, in the belly or in the side or they have the same tickling spots as children, basically, you get a laughing sound out of them. They're gonna be (makes noise) type laughing.

DE WAALAnd I feel you need to call that laughing. The facial expression is very similar to that in humans. The sound is very similar. It's very hard to not laugh yourself when you hear these sounds from them. That's how similar it is. And we need to call it laughing, even though that's an anthropomorphic term because if you don't, then you're sort of denying the connection that so obviously exists between us and the chimpanzee.

PAGEFrans de Waal, he has a new book out. It's called "Are We Smart Enough To Know How Smart Animals Are?" We're going to take a short break. When we come back, we're going to go to the phones. We've got a couple callers waiting. Some more lines are open, 1-800-433-8850. We're going to ask Frans de Waal about the implications of this research. What should it mean in our treatment and use of animals if we understand how intelligent they are? I hope you'll stay with us.

PAGEWelcome back. I'm Susan Page of USA Today sitting in for Diane Rehm. And we're joined this hour by Frans de Waal, psychology professor at Emory University, author of "Chimpanzee Politics" and "Our Inner Ape." He's joining us from Atlanta. He has a new book he's talking about. It's titled, "Are We Smart Enough to Know How Smart Animals Are?" Let's go to the phones and let some of our listeners join our conversation. We're going to start in McLean, Va., with Douglas. Douglas, welcome.

DOUGLASGood morning. About seven years ago I adopted a little parrot named Sunny, a green-cheeked conure. And I've been amazed by how smart she is. They don't talk a lot but I've learned to speak some parrot. And when I first got her, for example, her wings were clipped and we were outside in my mom's backyard, which is surrounded by woods, and a bird flew, startled her. She flew into a large azalea bush. I couldn't find her. And I kept saying, Sunny, Sunny, where are you? And then I realized, I have to speak parrot. So I gave the double click that we use when I'm out of the room an she clicked right back. Oh, there you are.

DOUGLASAnd then, another time, we were -- last year, she was perched in her cage, using her left foot on her perch. In her right foot, she had this two-inch long leather thing, like a shoelace that she likes to chew on, and the right side of her neck started to itch. And instead of dropping it and using her foot, she just used the leather thing like a back scratcher. And I thought, you used a tool. How smart.

PAGESunny does sound like a very smart parrot. Frans de Waal, what do you think? Are these signs of intelligence in Sunny?

DE WAALYeah, it is remarkable that, for the parrots, well, it's only recently, of course, we have Alex the parrot, which was studied by Irene Pepperberg and who can label a lot of things and can organize things. He can even count up. So they did studies with Alex where he would say, let's say, three pieces of pasta and then they would put a cup over it. And then he would see two pieces of pasta and they would put a cup over it. So at this moment, he could not see any of the pieces anymore and they would ask how many there are. And he would say, five. So he was counting up all the pieces that he had seen. And summation, like this, was always assumed to be uniquely human and to require language. And so parrots are truly remarkable.

DE WAALI have a very remarkable parrot story that came from my father-in-law, who is in France and who was a forester. And he, if -- he would sometimes bring dead animals to the kitchen and cut them open to see what was going on with them. And he had a special knife for that. And he told me once that his parrots -- he had an African gray -- was very scared of that knife. And so we started testing it out. We tested forks and other knives and all sorts of things. No, it was this specific knife that the parrot was really scared of. And he said he'd never done anything to the parrot with it. So the parrot must have deduced, from his observations in the kitchen, that this was not a good situation to be in, to see that knife.

DE WAALSo I think parrots are underestimated. But Alex the parrot studies and Griffin, a friend of Alex who was also used by Irene Pepperberg, I think they are now revealing a lot of the knowledge in parrots that we didn't suspect existed.

PAGESo Douglas says he learned to speak some parrot, clicking noises and so on. Is -- to what degree is it possible to communicate with animals in that way?

DE WAALWell, to a limited degree. I think parrots are very responsive to us. Dogs are very responsive to us. And so, yes, we can set up some sort of self-invented communication system with them. But there's of course other animals. Everyone who owns cats knows that cats are a bit less responsive. And so it depends on the species, I think, and how easily it is for us to communicate in their mode of communication. So, for example, with animals that have echolocation or animals that have super-sonic sounds, you're not going to be communicating very much.

PAGEAlthough, it's interesting, you write about how bats learn to navigate in a dark place and how humans didn't understand how that was happening. And it's now echolocation, I think, you described it. How does that work?

DE WAALWell bats need to -- they emit sounds, high-pitched sounds, that they need to -- that they receive back. And from the reflection they can measure how to orient and how to catch prey. It's very complex because a bat who flies around and is emitting these sounds and uses echolocation to locate its prey in pitch dark needs to calculate its own trajectory flying around, the trajectory of the prey flying around, and then calculate how to get there and to capture it. It's a very complex task.

DE WAALSome people don't look at that necessarily as cognition or intelligence because we don't do any of it and we cannot relate to it and so we classify it as, let's say, perception or something else. But it is actually a very complex task. And anyone who designs, let's say, radar for an airplane, knows that this is a very complex system. And that's basically what the bats are using. And so I think there has been an underestimation of capacities that animals have that we cannot really relate to. But there are many of those.

PAGEYou know, I read a story about a man who was blind. And he learned to ride his bike safely by using something like echolocation, that he would make sounds and it would somehow make him aware of hurdles ahead. Is...

DE WAALMm-hmm.

PAGEI mean, I wonder if there are ways in which our own lives can be enhanced by understanding more about the intelligence of animals?

DE WAALOh, I think so. I think -- what it does, this kind of work on animals, is that, first of all, it elevates the animals a little bit, instead of considering like dumb instinct machines, we now consider them actually as quite intelligent and also quite emotional, I must add. I don't talk much about emotions, but that's also part of the story, of course.

DE WAALSo that's one side. And on the other hand, we bring humans down a little bit. Because a lot of the things that we do, we overestimate how complex they are. And so if you can make the connection with animal behavior, it also shows that things that we do are maybe less complex than we think. So, for example, that happened in my studies of empathy. I do a lot of studies of empathy in the primates or in elephants or other species, which is basically that you're sensitive to the emotions of somebody else. And anyone who has pets at home knows that mammals are sensitive to our emotions and react to our emotions.

DE WAALAnd so once we are doing studies on empathy in animals, we now realize that the empathy mechanism in humans is actually less complex than we thought. It's a more basic mechanism than people thought.

PAGEAnd you, as evidence, you cite exhibitions of empathy even in very young children, before they've had a chance to absorb a kind of moral framework on which might encourage empathy.

DE WAALYeah. Yeah, so the -- it's actually interesting. How that happened historically is that the first studies on child empathy were done by Carolyn Zahn-Waxler here in the U.S., who would ask family members to cry and to cough and to say, I am in pain, and then see how young children responded. And very young children, under two years, already they approach and they touch these people and they stroke their face. And if they can talk, they say, how are you doing, and things like that. But she found, in the same studies, that the pets in the home were doing basically the same thing. The pets in the home also responded to the distress of others.

DE WAALAnd she felt, and I feel very strongly also, that if you call it empathy in humans, you have to call it empathy in other species as well. And so, in those early studies already, it was clear that it is a mammalian characteristic, it's not just a human characteristic.

PAGENow here's an email from Terry, who writes us from Indianapolis. Terry says, I recently had a discussion with a cardiology specialist about my dog. He said that animals don't anticipate death. I disagree with that. Why would any animal run from another, thinking that they are being preyed upon, if this was not the case? Why would a bird fly away from a cat or a gazelle run from a lion if they don't know that harm or death is possible? So let me ask you, do animals anticipate death?

DE WAALYeah, that's a difficult question. I can very easily see how an animal would escape from a predator without necessarily being fully aware that it can die. So I'm not sure that I would agree that this is proof that they are aware of upcoming death. I do think that many animals are aware of the death of others. As soon as you have an animal with attachments -- and many mammals and many birds, they have attachments, strong attachment -- as soon as you have that, the death of somebody else is going to affect you. It's a loss. And they sometimes respond very strongly.

DE WAALMy chimpanzees, for example, if one of the chimps dies in the group, they may not eat for several days and they may not vocalize for several days, meaning that they're very affected by the death of somebody else. Whether they know that they, themselves, can be in that situation sometime, whether they know about their own mortality is a different question and I don't think we have an answer to that. I don't think we know that.

PAGEAll right. Let's go to Grand Rapids, Mich. Brian has been holding on. Brian, you're on "The Diane Rehm Show."

BRIANGood morning. What a great topic. My comment came from the fact that Peter Gabriel, the musician, has been working with chimpanzees to make music. And I'm wondering, how does music affect the animals?

DE WAALYeah. I mean, I -- there are all sorts of stories of cows producing more milk when they hear Mozart or something like that. I'm not sure how well studied these tendencies are. But there is a whole field coming up of people who test animals and how they respond to music and how they respond to rhythm. So, for example, you can play a certain note on the piano in a certain rhythm and the chimpanzee is sitting on the other side and has also a piano and then see if the chimpanzee is going to mimic that rhythm. That kind of studies are being done.

DE WAALUntil now, I think the best animals in this regard are the parrots. The parrot family is really great at mimicking rhythm. Of course there's many animals who are -- many birds who are very good at mimicking sounds also. So people are testing this out and this whole field of, let's say, evolution of music appreciation and so on is coming up. But I don't think we have a lot of answers in this regard.

PAGEBrian, thanks so much for your call. Let's go to North Little Rock, Ark., and talk to Skip. Skip, you're on the air.

SKIPGood morning. Thanks for taking my call. I lived with a crow for several years and she had some remarkable behaviors which can only be seen as intelligent. One, she made up a game using a peanut and a paper cup. She would take the peanut and put it in the cup and pick up the cup in her beak and shake it to fling the peanut across the room. And she'd then go retrieve the peanut and put it back in the cup and repeat the process over and over again, clearly just enjoying this chance to throw the peanut farther than she could by herself.

PAGEYou know, Skip, that's such a great story. And we've got a similar email from Martha. Martha writes us, I saw a post of a crow using a plastic lid to slide down an icy rooftop. He would stand on the lid, slide down flapping his wings, and then take the lid, fly back up to the top of the roof and slide down repeatedly. He looked like he was having a really good time. Is it possible he was simply having fun? Frans de Waal, is it possible that crows just like to have a good time?

DE WAALOh, I think so. I think that crows have a large brain. And there's a lot of interesting research now on crows. And playfulness in general, animals who are very playful are often very intelligent animals. That's sort of a correlation. There's even -- people have now have described play for the octopus. And I'm not sure that that's really what is happening. But certainly in crows, also if you see crows flying or ravens -- ravens sometimes fly even upside-down, which is sort of ridiculous. They are birds that, in the wind, they whirl around and sometimes they go upside-down and they fly a distance like that. And that seems all extremely playful and seems all straight, fun loving.

DE WAALThe story of the first caller on the crow who was hiding object in a cup, that is actually very common crow and jay behavior is to hide things. And they love to do that. I used to have crows as a student, or jackdaws, which are European little crows. And in my room, I would often hide objects and then see if they could find them. And in order to do that, they have to have object permanence. They have to understand that an object that they cannot see anymore is still there. Because otherwise why would you be looking for it? And we played that kind of games with them. So, yes, crows are extremely intelligent animals.

PAGESkip, thanks very much for your call. I'm Susan Page and you're listening to "The Diane Rehm Show." We're taking your calls, 1-800-433-8850, and we're reading your emails, drshow@wamu.org. Well, you talked, Frans de Waal, about animals having -- some animals having a sense of play. How about a sense of justice or fairness? Do animals have a sense of that?

DE WAALYeah, that's one of the surprising things we found. We did studies of cooperation in monkeys, can they pull together at a task. And in that context, we discovered that actually they're sensitive to what they get compared to what somebody else gets. And so we started doing experiments on fairness with them, where two monkeys would do the same task, but they would either get equal rewards or unequal rewards.

DE WAALAnd if you give, for example, grapes to one monkey and cucumber slices to another monkey -- now grapes are 10 times better than cucumber slices for them -- the one who get cucumber sort of is pissed off, is not happy about this situation and starts to protest and starts to throw the cucumber away, even though anytime you give a piece of cucumber to a monkey he will eat it. But under these circumstances, where the other one is getting much better food, they don't eat it and they throw it away, which is what economists call an irrational response, because a cucumber slice is better than no cucumber slice.

DE WAALAnd humans have the same reaction. So this kind of games is also played with humans. We have the same angry reactions. Actually, the Bernie Sanders theme in this election is very much, we're all cucumber eaters, where there's a few grape eaters. And basically this whole feeling of justice is present in monkeys already. And then with chimpanzees it even goes further. Chimps are apes, much closer to us. And chimps have a more human-like sense of fairness where they may even refuse the grape -- the one who gets the grape refuses the grape till the other one also gets a grape. So that's much closer to what we do.

DE WAALAnd if you now ask me, what is the difference in the sense of fairness between, let's say, a chimpanzee and a human? I don't know anymore. I'm not sure that there is a major difference between the two.

PAGESo what's interesting is not only does the chimp who doesn't get -- who does get the cucumber -- and who wants a vegetable when you can have a fruit -- not only does that chimpanzee respond but the chimpanzee who gets the better treat...

DE WAALYeah.

PAGE...also has a sense of fairness about it.

DE WAALWell, I think that relates to the fact that chimps can think ahead. There's a lot of experiments now that show that. And so they can anticipate that if they take the grape and the other one doesn't get one, that it causes trouble with the other one. And I think that's also the same reason why humans have a sense of fairness, is that we understand that an equal distribution is actually better for cooperation. It creates better, more harmonious relationships. And that's why an unequal distribution, as we're having at the moment in our economy, is actually a dangerous thing to have because it creates discord.

DE WAALAnd so the monkey studies, even though they seem very far removed from our current economic conditions so to speak, they already hint that some of these tendencies that underlie our protests and our acceptance of certain situations.

PAGEYou know, you've -- you write this book, "Are We Smart Enough to Know How Smart Animals Are?" saying that we have misjudged how smart animals are. Do you have a sense of what animals think of humans?

DE WAALI think animals who live with us, they have, of course, they have opinions about us. And I think animals judge us mostly on whether we are useful or dangerous to them. So if we feed them, they have a different relationship with us than if we hunt them or kill them. And so they judge us on what we do to them, basically, most of the time. I'm not sure that they, apart from that, that they're judging us. I'm not sure that they're that interested in us.

PAGEOkay. This is Frans de Waal. He's the primatologist, he's the author of this new book, "Are We Smart Enough to Know How Smart Animals Are?" We're going to take a short break. When we come back, we'll go to the phones. We're going to continue our conversation. You can give us a call, 1-800-433-8850. Send us an email, drshow@wamu.org. Or find us on Facebook or Twitter. Stay with us.

PAGEWelcome back. I'm Susan Page of USA Today, sitting in for Diane Rehm. We're talking to Frans de Waal, psychology professor at Emory University, author of "Chimpanzee Politics" and "Our Inner Ape." He is director of the Living Links Center at the Yerkes National Primate Research Center, and he's the author of a new book. It's titled "Are We Smart Enough to Know How Smart Animals Are." And Frans de Waal, here we've got an email from a skeptic, Glen in Baton Rouge, Louisiana, and he writes us, if animals truly recognize themselves, no birds would fly directly into a reflective picture window and thus to their sad demise. No animal would go into traffic. After all, a line of speeding cars much look very much like a stampede or at least very large predators.

PAGEAs intelligent as we believe animals are, I see no evidence they can communicate complex feelings, understand their place in the universe, calculate the trajectory needed to send a probe to the outer planets, compose a symphony or write a novel, let alone understand creation and the soul. What would you say to Glen?

DE WAALWell, we're not saying, for example, the mirror, that's the first example that he uses, that all animals have that understanding. That's actually only a few large-brained animals like chimpanzees and elephants and dolphins, and humans of course, who understand the connection between the mirror image and themselves. There's a lot of animals, for example fish, and there's a lot of small birds, who keep attacking the mirror image and really don't get it. So there's an enormous variability in animals, and an animal like a chimpanzee is definitely capable of planning ahead. People have tested that.

DE WAALSo you can, for example, give a chimpanzee the choice between a tool that he can use 12 hours later to get something really good or an apple. So the chimpanzee now needs to decide, I can take the apple and immediately eat it, or I can take the tool, and 12 hours from now I can get something much better. And the chimp will take the tool. So the chimps are thinking ahead, and there's all sorts of tests who have found it now.

DE WAALThat they don't make symphonies or calculate a probe into space, how many -- my question then is how many people do that. And a lot of these can do that right away. A lot of these capacities, like making an iPhone, for example, they are the product of several thousand years of scientific accumulation that is going on in our species. There is not a single person who has invented the iPhone. There are thousands of people who have worked on the science behind it, and now we have that product in our hands, and we think we invented it, but actually it is an accumulation of humans who has done it.

DE WAALAnd so yes, there are differences between us and other animals. But I feel we need to sort of judge every species on their own merits and see what they need to do in their environment and how good are they at it and is it an intelligent way of going about. And so crows can do certain things that we cannot do, and we can do certain things that crows cannot do, and instead of making that a contest, who's at the top of the pinnacle, it is more like a comparison of different intelligences and different cognitions across the board.

PAGELet's talk to Laura. She's calling us from Rye, New York. Laura, you're on the air.

LAURAGreat, thanks for taking my call. I, unlike the previous caller, I am completely convinced about the intelligence and empathy of animals and their ability to grieve and to be creative and all that, which leads me to my question. How do you square that with killing them and eating them? You know, if they are not so dissimilar from us, just because they're different species, how do we justify, you know, caging them, mutilating them and then slaughtering them?

PAGEAll right, Laura, thanks very much for your call.

DE WAALYeah, I do think all this work on animals, which has come up in the last 20, 25 years, is having a moral impact. I'm not sure it's as radical as what you propose, that people would stop eating them, but you can already see, for example, our attitude to circuses has changed, our attitude to killer whales in captivity has changed. I myself, I work on chimpanzees and NIH, the National Institutes of Health, has decided that chimpanzees cannot be used for biomedical studies anymore.

DE WAALSo there are changes coming about. They will at some point reach the agricultural industry, as well, I think. The agricultural industry has -- uses in fact far more animals than anybody else, and that's where the big changes need to come at some point. And I think yes, the work that we do is going to have moral implications and has them already, as you can tell at the moment.

PAGEWe had a show just last week on the Diane Rehm Show about a book that argued, for example, laws and regulations that gave chickens more space when they were being bred or treated cattle in a different way. Here we have a tweet from someone in South Dakota, who writes, is your guest a vegan or a vegetarian? If not, which animals does he feel comfortable eating? Are you -- if you don't mind me asking, are you a vegetarian yourself?

DE WAALNo, I'm not, no, and I'm too much of a biologist, I think. In nature, everything eats everything. Animals eat plants. Plants eat sometimes animals. Animals eat animals. And so -- but I do feel, it's not the eating part for me, it's the treatment part. And so for example I've stopped eating mammals for that reason. But I think we need to get into a better treatment of animals, even if we keep eating them.

DE WAALAnd my ideal would actually be that we reduce meat consumption by, let's say, 50 percent and that the meat that is being displayed in supermarkets or wherever has a little picture attached where I can see how that animal was kept. That would be my preference is that -- not some sort of general statement like this is a free-range chicken, but more like a picture of the actual conditions under which these animals that are being offered -- so that we can search, and I think the public will be responding to that, maybe not all of them but maybe half of the people will be responding to knowing more about the background of these animals, and maybe we can push things that way.

PAGEYou know, I have often thought of chimpanzees as intelligent animals, dogs and cats, anyone with a pet would say they definitely have an intelligence. One of the surprising things in your book is about the intelligence of octopuses. I hadn't really thought of them as being an intelligent species. Tell us about what they can do.

DE WAALWell, the octopus has a large brain for a mollusk and has a lot of neurons spread out over its arms, a lot of ganglia. And so a lot of the nervous system, which in our case is very concentrated, in their case it's very distributed over the whole body, which makes it for us impossible to understand the octopus, really, because it's more like an Internet than a centralized nervous system.

DE WAALAnd the octopus can, for example, change color, which means it needs to perceive the color around it and then fit in, blend in, and so adjust and also in terms of posture and locomotion, adjust to the environment so that it becomes invisible because many animals in the ocean eat the octopus. And there's even a mimic octopus who can mimic the movements of certain fish and certain sea snakes and adopt the colors of them, which probably is also based on them perceiving these animals and then mimicking their movements and mimicking their color, which -- again we usually don't look at these things as necessarily a form of intelligence, but it requires cognition to understand how you blend in in the environment, and that's a sort of -- very hard to understand for us the kind of cognition, but that's what the octopus has.

PAGEIn your book, you say that in some experiments, octopuses have been able to open a pill bottle that has a child-proof cap, which I can tell you I have struggled with myself. And also that...

DE WAALIt's very complex what they do, and so there's also experiments on whether they recognize human faces. And so the experiment goes, you have a friendly human, who gives them food, then you have an unfriendly human who pokes them with a stick, and both humans have a blue overall on so the clothes are the same, but their faces, of course, are different. And then they see how the octopus responds to them. And after a few of these experiences, the octopus is very eager to approach the friendly human and eager to get away from the unfriendly one, or they may even spit water at the unfriendly one.

PAGEI can't tell you how surprising that is to learn. Let's go to Manassas, Virginia, and talk to Kumar. Kumar, you're on "The Diane Rehm Show."

KUMARHi, good morning. I absolutely adore your guest. He's great. Thank you very much for the program. I wanted to tell you just a quick story about -- I used to live near Gracie Mansion in Manhattan, and there's a big park there, and there's a dog run. So my dogs would go into the dog run. They weren't interested in playing, they were both rescues, and so they used to sit up on the bench with the people. And I used to run around and play with the dogs, trying to engage them, until one day a woman started laughing and noted the ridiculousness of my playing with the dogs while my dogs watched me in the dog run.

KUMARBut I was in Gracie Mansion Park, and there was a crow that had been tied up in string, and it was flopping around on the ground. So I grabbed a newspaper, picked it up, and there were doctors' offices across the streets. And my dogs followed behind me, off leash. We went into the doctor's office, undid all of the strings that were around the crow, and the crow stayed in my hands the whole time, until we got to the front door.

KUMARAnd when we got to the front door, the crow flew out of my hands, went up into the tree and joined another crow. And they were talking to me. I was talking to them, and they were talking to me. And when I walked underneath, they were talking at me from atop a tree. And I just want to say they're just miraculous, all animals are. I have a lizard that lives in my mailbox that lets me pet it.

DE WAALYeah, yeah, yeah, that happens here, too, in Georgia. I live in Georgia, so we have sometimes snakes living in the mailbox. So yeah, the crow story is interesting because there was once a story of a whale, I think it was a humpback whale, who was tied up in fish nets, and they liberated -- the human swimmers went around the whale to cut all the nets. And the whale actually came back to them to contact them one by one, the ones who had rescued him, and there was a clear impression on the part of the humans who had done this that the whale was grateful and sort of said goodbye to them.

DE WAALAnd the saying goodbye is really interesting. I had a chimpanzee who we had to call out of the group every day, in the middle of the day, for treatment and because she was raising -- actually she was raising a baby chimp on the bottle, and we had to call her out in the middle of the day. And she would do the rounds of the whole chimp colony, which was on a pretty big island with 25 chimps, she would do the rounds and say goodbye in the middle of the day if she would come in.

DE WAALAnd so saying goodbye is really interesting because we are of course used to animals greeting us, which is a response to your presence after an absence, but saying goodbye requires that you anticipate a separation. And some species have that capacity to do that.

PAGEWe have an email from Patricia in Rochester Hills, Michigan, who asked, please discuss the intelligence of pigs. Patricia doesn't say why she's particularly interested, but let me put the question to you.

DE WAALYeah, I think pigs are underestimated. Maybe it's also because if we were to expose how smart pigs are, because I think they are probably as smart as dogs, if we were to expose that, people who have second thoughts about what they eat. But pigs are definitely smart animals. And a few experiments have been done but very little, I would say, given the number of pigs that we have around. Very little has been done. But pigs are considered very smart animals.

PAGEI'm Susan Page, and you're listening to the Diane Rehm Show. We're taking your calls for Frans de Waal about his new book, "Are We Smart Enough to Know How Smart Animals Are." Let's go to Washington, D.C., and talk to Phil. Phil, hi.

PHILHi, how are you?

PAGEGood.

PHILI'm calling just because the guest answered that some children or I should say some species of animals have intelligence that's comparable to, say, young children or perhaps mentally handicapped humans. I wanted to know, because we of course as humans value the rights of those people, whether it's young kids or mentally handicapped humans, I wanted to know how that translates into the animal rights movement and whether or not the guest -- I'd like his thoughts on how his research affects conservation efforts if we assume that some animals maintain the same or similar level of intelligence to some humans.

PAGEPhil, thanks very much for your call.

DE WAALYeah, I think conservation is sort of a separate issue. We are really struggling with conservation of the great apes because they're really disappearing. And I don't think that's a rights issue necessarily. It's just that we're worried about certain species disappearing and a habitat disappearing, and I don't know what we can do about it because we have little influence over that.

DE WAALAs far as rights, I always feel rights is such a black and white issue. It's like you have rights, or you don't have rights. And I'm more of what they usually call an animal welfare-ist. I feel we need to treat animals as best as we can under the circumstances, and that's also why certain treatments of animals don't sit well with me, and this applies to both zoos and circuses and research institutions. It doesn't mean that we need to stop all these things, but we need to really closely pay attention on how we treat animals.

DE WAALAnd for me that's not necessarily a rights issue. It's more like a human obligation, if we take care of animals that we take care of them in the appropriate ways.

PAGEPhil, thanks for your call. Here's an email from Jerry. He writes us from Conway, Arkansas. He says, humans often continue to believe things that are demonstrably false. When confronted with irrefutable evidence, people dig their heels in deeper and continue their false beliefs. Is there an equivalent in animal behavior, and can you conceive of a good test for that?

DE WAALWell certainly the people who, in the last century, had this very simplistic view of animals as either simple learning machines or instinct machines. These people are still around. That's an older generation of scientists. I think the younger generation doesn't think like this anymore. They're very open to cognitive abilities in animals and very open to the idea that every species is different given their circumstances.

DE WAALBut yes, there is resistance, and it is very hard to change the minds of people who have grown up in a certain system of thinking. It's very hard to do that. But I think it's happening at the moment, certainly with regards to animal cognition, that the emphasis is changing, and the perspective is changing at the moment.

PAGENow that's humans changing their mind. I think Jerry is asking if animals are sometimes very obstinate, even about things that are kind of demonstrable true.

DE WAALYou mean that animals change their mind? Oh animals...

PAGEThat animals refuse to change their mind. You can prove to them that they shouldn't do something, or they should do something, and they refuse to do it because they're just that stubborn.

DE WAALWell that also happens in our research. When we teach chimpanzees new solutions to new problems, sometimes they hit at the wrong one, and they keep persisting. Yes, there are individuals who are what we call conservative. So they have a solution, which is not perfect, and they keep doing it because it has given them rewards once or twice, and they cannot get over that. So being resistant to change is not -- I don't think is uniquely human.

PAGEDo you have a -- after all these years of animal study, do you have a favorite animal of your own?

DE WAALYeah, there are certain chimpanzees that I've very attached to, and sadly enough, my all-time favorite chimp, which was a female named Mama, who lived at the R&M Zoo, has died just a couple of weeks ago. She was 59. She was the absolute matriarch of that colony for the last 40 years or something. She was absolutely -- she was not dominant over the males, but she had a very prominent political role, and no one could get around her. And she died just a few weeks ago.

PAGEOh, well, I'm -- we're sorry for your loss there. Let me read a final comment from Joey. He posted it on "The Diane Rehm Show" website. He wrote, anyone who has spent time with an animal has got to accept that their internal life is more complex than we know. Human beings are not unique. We are part of the web of life. I think that's very consistent with your book, Frans de Waal.

DE WAALYeah, I consider human cognition as a variety of animal cognition. We are exceptionally smart, but we are not fundamentally different, I would say, from other species.

PAGEFrans de Waal, author of "Are We Smart Enough to Know How Smart Animals Are." Thanks so much for joining us this hour.

DE WAALYou're welcome.

PAGEI'm Susan Page of USA Today, sitting in for Diane Rehm. Thanks for listening.