What Are Animals Saying?

Can we crack the code of animal communication? Airing April 25, 2018 at 9 pm on PBS Aired April 25, 2018 on PBS

Program Description

From singing whales and squeaking bats to thumping spiders and clicking dolphins, the world is filled with the exotic sounds of our fellow creatures. What are they saying? While we believe language sets us apart, some animals demonstrate they can learn our language—like Chaser the dog, who recognizes hundreds of words, and Kanzi the bonobo, who appears to have a sophisticated understanding of spoken English. But can we decode their own communications? NOVA Wonders follows researchers around the globe who are deciphering an amazing array of clues that reveal how animals share information critical to their survival. Will we one day be able to write the bat dictionary or decode the hidden sign language of chimps? And what can these findings tell us about the roots of our own language?



NOVA Wonders: What Are Animals Saying?

PBS Airdate: April 25, 2018

TALITHIA WILLIAMS (Mathematician, Harvey Mudd College): What do you wonder about?

ERICH JARVIS (Rockefeller University): The unknown.

FLIP TANEDO (University of California, Riverside): What our place in the universe is?

TALITHIA WILLIAMS: Artificial intelligence.

ROBOT: Hello.

JARED TAGLIALATELA (Kennesaw State University): Look at this. What's this?

KRISTALA JONES PRATHER (Massachusetts Institute of Technology): Animals.


ANDRE FENTON (Neuroscientist, New York University): Your brain.

RANA EL KALIOUBY (Computer Scientist, Affectiva): Life on a faraway planet.

TALITHIA WILLIAMS: NOVA Wonders, investigating the biggest mystery…

J.A. JOHNSON (Harvard University): We have no idea what's going on there.

JASON KALIRAI (Space Telescope Science Institute): These planets in the middle, we think are in the habitable zone.

TALITHIA WILLIAMS: …and making incredible discoveries.

CATHERINE HOBAITER (University of St Andrews): Trying to understand their behavior, their life, everything that goes on here.

DAVID COX (Harvard University): Building an artificial intelligence is going to be the crowning achievement of humanity.

TALITHIA WILLIAMS: We are three scientists, exploring the frontiers of human knowledge.

ANDRE FENTON: I'm a neuroscientist, and I study the biology of memory.

RANA EL KALIOUBY: I'm a computer scientist, and I build technology that can read human emotions.

TALITHIA WILLIAMS: And I'm a mathematician, using big data to understand our modern world. And we're tackling the biggest questions…

SCIENTISTS: Dark energy? Dark energy!


DAVID T. PRIDE (University of California, San Diego): There's all of these microbes, and we just don't know what they are.

TALITHIA WILLIAMS: …and the cosmos.

On this episode: animals make all kinds of noise, but what does it mean?

DAMIAN ELIAS (University of California, Berkeley): What they're telling the female is, "I'm free of parasites."

TALITHIA WILLIAMS: Can we crack these mysterious codes?

CATHERINE HOBAITER: The gesture means "travel with me."

JARED TAGLIALATELA: His vocabulary was like a two-and-a-half-year-old human child.

KLAUS ZUBERBUEHLER (University of Neuchâtel): This is Dr. Doolittle's dream.

TALITHIA WILLIAMS: NOVA Wonders: What Are Animals Saying? Right now.

All around us are alien tongues, and they don't come from space.

ANDRE FENTON: From whale songs and wolf howls, to birds chirping and dolphins clicking…

RANA EL KALIOUBY: …the animal world is filled with mysterious conversations.

TALITHIA WILLIAMS: Could we ever tap in? We like to think that language sets us apart from the beasts.

ANDRE FENTON: But are we really all that special?

TALITHIA WILLIAMS: Today, scientists are starting to decode those communications, discovering that we might not be alone.

ANDRE FENTON: I'm Andre Fenton.

RANA EL KALIOUBY: I'm Rana el Kaliouby.

TALITHIA WILLIAMS: I'm Talithia Williams. And in this episode, NOVA Wonders: What are Animals Saying? And what does it say about us?

ROBIN QUEEN (University of Michigan): Come on.

When I'm working with Zach…

Lie down.

…it seems like magic.

Zach, that will do. Zach, come here.

Experiencing that kind of connection with a dog…

Come by. Lie down.

…you're in sync, and it's like any other connection you have with someone…

Lie down.

…where you really get along, and you're like, "Oh, wow, that was an amazing conversation."

TALITHIA WILLIAMS: Robin Queen is a linguist and competitive sheep herder from the University of Michigan, and, like many of us, she likes to think she can talk with her dog.

ROBIN QUEEN: I think we are, as humans, we're fascinated by the idea, the Dr. Doolittle idea. We want that to be true in some way. When I started working with the dogs, I was shocked at what they could do.

Don't lose it. Lie down.

TALITHIA WILLIAMS: And for border collies like Zach, herding sheep is just the beginning.

TECUMSEH FITCH (University of Vienna): Get Spider.

TALITHIA WILLIAMS: They appear to have a sophisticated understanding of language.

TECUMSEH FITCH: Get Spider. Bring it over here.

Their ability to learn human words are almost unlimited. It seems to be, you know, every year a new dog comes by with a larger vocabulary.

TALITHIA WILLIAMS: A glance at YouTube proves the point.

YOUTUBER 1: Tessa, get pumpkin.

TALITHIA WILLIAMS: Tessa can recognize four different toys.

YOUTUBER 1: Good girl, bring it over here. Excellent.

Get pig.

TALITHIA WILLIAMS: And that's puppies' play compared to Gable; he knows a hundred and fifty.

YOUTUBER 2: Good boy.

Find Meow. Find Meow.

TALITHIA WILLIAMS: But all of these pooches pale in comparison to Chaser…

CHASER'S HANDLER: There's Meow. Come here.

Give me the ball.

TALITHIA WILLIAMS: …who has been proclaimed the world's smartest dog.

ROBIN QUEEN: Chaser was taught the individual names of over a thousand objects. And that's really pretty cool, because it starts to try and get at that question of, "How special are humans?"

TECUMSEH FITCH: Chaser can understand hundreds of words, but all she can do is say, "Ruff." She can't actually say any of those words back. Now, what would be really impressive is when Chaser starts saying, "You go get the bunny." Then I'd be impressed.

CHASER'S HANDLER: Find Roach. Find Roach.

TALITHIA WILLIAMS: But as impressive as Chaser's feats are, do they qualify as…


TALITHIA WILLIAMS: Since the dawn of history, we've imagined animals to be like us.

(Mr. Ed Television Series, Film Clip): I'm a horse, not a guinea pig.

TALITHIA WILLIAMS: Our stories are filled with talking creatures. But what's the reality?

Well, to answer that question, let's talk about language. To scientists, it's a learned set of symbols that can be combined into infinite meanings. Just consider these: "Dog bites man." "Man bites dog."

By just changing the order of a couple words, the meaning of the message is completely different.

Well, this is the cornerstone of human language. It allows us to tell stories, write poetry, negotiate contracts, whisper sweet nothings. The question is, "Is this skill unique to us?"

FILM NARRATOR: There are two chimpanzees in Rome who have brought a new "twist" in communication between animal and human.

TALITHIA WILLIAMS: For over half a century, scientists have been working with our closest relatives to answer that question.

FILM NARRATOR: Viki was adopted when her own mother couldn't feed her anymore.

TALITHIA WILLIAMS: At first, scientists tried teaching language to chimps by raising them like children. Perhaps one of the most famous of these was Viki.

FILM NARRATOR: She loves all the attention and affection. And she loves everyone.

VIKI'S TRAINER: Do this, Viki.

TALITHIA WILLIAMS: Not only is this approach now considered unethical, it didn't work. After seven years of intense training, she could barely utter four words.

TALITHIA WILLIAMS: So scientists switched to sign language.

FILM NARRATOR: If you watch Koko closely, she's learning to put her fingertips to her mouth to sign "eat."

TALITHIA WILLIAMS: Apes, like Koko the gorilla, hinted that apes have some ability for language.

FILM NARRATOR: Koko proved an adept student. Everyone was amazed at how well the little gorilla was catching on.

JARED TAGLIALATELA: Let's do just a little bit more work, and then we'll get a whole bunch of surprises, okay?

TALITHIA WILLIAMS: But it wasn't until this guy came along that researchers discovered exactly how impressive that ability was.

JARED TAGLIALATELA: In the world of ape cognition, Kanzi is, you know, Elvis Presley.

All right, Kanzi, come on. Tell me what this is. What's this a picture of? Very good.

TALITHIA WILLIAMS: Instead of sign language, Kanzi learned these. They're called "lexigrams," abstract symbols that represent words.

JARED TAGLIALATELA: What's this? Look at this. What's this? An egg. Very good; that's an egg. Good job.

TALITHIA WILLIAMS: And Kanzi has learned over 400 of them.

JARED TAGLIALATELA: Good, keep going. Good job, Kanz. Good, Kanzi, good stuff.

TALITHIA WILLIAMS: Amazingly, he started teaching himself this skill, as a baby, over 30 years ago.

KANZI'S TRAINER (Film Clip): I want you to go put the onions in your hot food.

TALITHIA WILLIAMS: Kanzi might have been around 11 or 12 at the time. His vocabulary, spoken English vocabulary, was assessed in comparison to a two-and-a-half-year-old human child.

JARED TAGLIALATELA: Now, I want you to take the spoon and put it on top of the bucket. Can you do that for me? Can you put it on top of the bucket?

TALITHIA WILLIAMS: Watching him today, at 37, it would appear his language ability goes well beyond vocabulary.

JARED TAGLIALATELA: Can you put it on top of the bucket? Very good. That's a good job.

So, I can ask Kanzi, "Hey, Kanzi, can you put the blanket on your head?" And then I can ask Kanzi, "Can you sit on the blanket?"

Can you put it on your head?

Nice job, Kanzi, very good, very, very good. Can you put the blanket on the cube? Now can you sit on top of the blanket? No, sit with your bottom on top. Good job, Kanz, that's it. Very good.

What he's obviously doing, in that context, is understanding not only the individual words, but the order in which they're arranged. I think that's a big deal, because that is one of the foundational elements for human spoken language.

CATHERINE HOBAITER: Kanzi's a huge deal. The studies with Kanzi, and with the other apes like him, allowed us to get a window into what great apes might be capable of in terms of learning our world and our communication.

JARED TAGLIALATELA: Science has gained a whole lot from apes like Kanzi, but in all likelihood, Kanzi will, sort of, be the last of his kind.

Moving forward, I think our approach is shifted to one where we're starting to focus more on what the animals are doing with one another.

KOKO SIGNING: Cat gorilla have visit, Koko love.

TALITHIA WILLIAMS: Today, the questions scientists are asking is not whether animals can learn our language…

KANZI'S TRAINER: …could you take my shoe off, please?

TALITHIA WILLIAMS: …but if we can learn theirs.

PETER TYACK (University of St Andrews): It's very interesting that humans, who are very caught up in our own intelligence, when they wanted to understand whether other animals had a language like ours, the best thing we can think of is, "Can we teach that other species to speak our language?"

TECUMSEH FITCH: What you need to do, if you want to understand animal communication, is leave our own language behind. Try, as much as you can, to become more like an animal and just not think in words. And see what they're seeing and understand what they're feeling, what they're, what they're communicating about.

TALITHIA WILLIAMS: And when you do that, you discover a whole new world, hiding in plain sight.

CATHERINE HOBAITER: When I first came to the rainforest, this was an alien world for me. I had no clue what to do, how to be, how to move around in here.

TALITHIA WILLIAMS: Budongo Forest, Western Uganda: Cat Hobaiter is setting off for work.

CATHERINE HOBAITER: Trying to understand their communication means understanding their behavior, their life, everything that goes on here. I am the luckiest person in the world, 'cause I get paid to run around a rainforest with wild chimps. I, I love this.

TALITHIA WILLIAMS: She's spent over 10 years studying these chimps.

CATHERINE HOBAITER: It's been a pretty incredible thing to be able to watch some of these chimps from the day they were born until adulthood. And I get to see the little detail, the soap opera of their life. I'm an outside observer, but I've been here for so long, I feel a part of the family, sometimes.

TALITHIA WILLIAMS: In the process, she has unearthed a hidden form of communication.

Those scratches, shaking of trees, to Cat they aren't random motions, they're part of an elaborate code, a secret "language" of chimps.

CATHERINE HOBAITER: All of these gestures are a part of chimpanzee communication, and they grow up with them.

To humans, it might seem really subtle, like a tiny little push or a tiny little pull, and that's really hard for us to see; but I think to the chimps, it's very obvious what's going on.

So, she's sitting down, looking up at her daughters, and she's giving a big scratch. So, she's ready to go.

TALITHIA WILLIAMS: That's Harriet. And that scratch, it's not because she has fleas, it's actually a signal to her daughter, Harmony.

CATHERINE HOBAITER: And the little one's coming down now.

Well, that scratch has two meanings. One of them is "groom me," and the other one is "let's travel together."

Oh, ho, ho, ho. The loud scratch got her to come down. They're all going to go down the tree, and that's them leaving together.

TALITHIA WILLIAMS: To the untrained eye, the gestures don't look like much. Only after hundreds of days and even more nights poring over 4,000 hours of video did Cat start to put the pieces together.

CATHERINE HOBAITER: So, in this case, the gesture is a big loud scratch, but here it means "travel with me; travel together."

TALITHIA WILLIAMS: The reason she thinks Harriet's scratch means "let's travel" is because she has seen the same action and response dozens of times before.

CATHERINE HOBAITER: So, you've got Klaus, and the little young male chimp, and his mom, Kalima. And he's ready to go, he wants to travel, so he gives this big scratch and then he comes around the back of his mum, climbs on, and they travel away together.

I sometimes look at this, and I wonder if I am seeing things, if it's really there, if I'm, you know, if it's all kind of in my imagination. And it's not until you're watching the videos over and over and realizing that you see this little movement, but afterwards every time you see that little movement, the other chimp does something that you start to think, "Oh, there might be something in there."

TALITHIA WILLIAMS: Like this one. If you look carefully, you can see the mother chimp raising her foot.

CATHERINE HOBAITER: In this case, the gesture is a foot present, and it means "climb on me." This is a hard one to see.

You've got the mother, Jenny, walking down the transect, and her little boy, James, who she'd like to have climb on her back. What she does is, she stops, she lifts her foot up, and she looks back over her shoulder at him. So, you know that she's waiting for him. She's waiting for him to give the response that she's looking for. And, in this case, he climbs on, and they travel away together.

TALITHIA WILLIAMS: But it's not enough to just see the same gestures over and over, she needs to see some evidence of a back-and-forth, a conversation.

CATHERINE HOBAITER: In this case, he wants her to come and be groomed by him, so he's going to give these big scratches, and he's waiting for a response. So, that didn't work; she didn't do what he wanted, she didn't do anything. So, he here gives a little object shake, and he gives the scratch again, so he's combining those two gestures, but still nothing from her. She's just not interested at the moment, so he's giving a really exaggerated version.

It's like a back and forth between the two of them: big scratch, object shake, "Come on, I want to groom you. Come over here." That seems to have done the trick, because she comes down, and they start grooming.

The reason I know this is an intentional gesture, and not just a chimp shaking a branch in the forest, is because he gives it and he waits for that response. And when he doesn't get what he wants, he gives it again. He persists. But once he does get what he wants, then he stops. And it's the same as human conversations and communications. After you've passed me the thing I'm asking for, then I don't keep on asking for it.

TALITHIA WILLIAMS: Cat has come up with over 60 different gestures, with more than 19 different meanings.


"Groom me."

And we're still picking up, possibly, you know, finding new ones all of the time.

"Move closer."

I think in terms of an animal to human system of translation…


…we probably have the most meanings translated here.

"Let's go."

"Let's be friends."

And that's…certainly, compared to a lot of other animal systems of communication, it's much richer. It gives us much more detail than we've been able to find elsewhere.

"Let's have sex."

It's easy for us to want to focus in on language. You know, we're quite self-obsessed as a species, we want to know, what is it that might be special or different about ourselves? But what the chimps have going on here is their own incredible rich world of communication. And it would be really easy just to focus in on their vocalizations, but the real subtlety and texture and all of those rich meanings that we see in the gestures every day would be lost.

TECUMSEH FITCH: I think, as humans, we're so language-centered that sometimes it's easy to forget that language is not the only way we communicate-language is just one of the channels of communication that we have as humans-and also not to think that language is the only model for animal communication.

RANA EL KALIOUBY: In fact, we humans communicate with dozens of different expressions and gestures. When you think about it, animals have all this and so much more. Everywhere you look, you find elaborate systems of non-vocal communication. From elephant body language to honeybees telling their buddies how far and where to fly, even the simplest of creatures seem to have a lot to say.

TALITHIA WILLIAMS: Just consider these guys, Habronattus formosos, jumping spiders.

DAMIAN ELIAS: Spiders have some of the most unusual communication systems. It really is kind of like this fascinating puzzle, and you use as much imagination as possible to, sort of, crack this language.

TALITHIA WILLIAMS: Damian Elias from U.C. Berkeley spends his life listening to arachnids.

DAMIAN ELIAS: Stay there. There you are. Come on.

Working with spiders is not a normal occupation.

TALITHIA WILLIAMS: You might be surprised how much this tiny creature has to say, especially when it comes to love.

DAMIAN ELIAS: Because these females only mate once in their lifetime, they need to make that choice count; that decision better be as informed as possible.

TALITHIA WILLIAMS: So, you want to know what spiders are saying, you need to be a bit of a voyeur.

DAMIAN ELIAS: Oh, my god, I've probably spent tens of thousands of hours watching spiders have sex and hearing spiders have sex and thinking about spiders having sex.

So, he increases the thumps as he gets closer. Now he is really inching up closer.

It's like you're trying to decode some type of alien language. It's only with technology that we have now, that we can even try to really decode what's going on.

So, what I'm going to do now is I'm going to make a female decoy. I take a euthanized female and then take a pin that has a small drop of beeswax, and then I lower that pin onto the female. And now, using this decoy, we can have the male court it.

Here we have our courtship arena, which is essentially a needlepoint frame and female pantyhose with some pieces of reflective tape on them.

I'm going to place our female decoy into this little rig, where it's hooked up to this kind of pulley system, and with it we can put her in a lifelike posture, so she can fool a male. And so, how we record these displays is using a laser vibrometer, so, this is what you see right here.

TALITHIA WILLIAMS: The laser vibrometer converts vibration into sound.

DAMIAN ELIAS: Spiders don't have ears, and so they can't detect airborne sound. Instead, spiders detect vibrations with their feet.

TALITHIA WILLIAMS: With the stage set, it's show time.

Think of it as a 5-act song and dance routine. Act One:

DAMIAN ELIAS: So, he's doing a sidling display, there. They're really exposing a lot of the ornaments that they have on their face. And those oftentimes are species-specific. Females need to know that it isn't a predator that's trying to eat them.

And so you have this very safe display that starts very far away, and as soon as he gets close to the female, he will start to do the introductory display.

TALITHIA WILLIAMS: Now, the "singing" kicks in.

DAMIAN ELIAS: There. There is the introductory display. Essentially, it's like, you know, "Listen to this: now I'm going to start to tell you a bunch of information about myself."

And so now he's going to go through a series of different signals.

TALITHIA WILLIAMS: First the scrape.

DAMIAN ELIAS: Right there; that's a scrape.

The parasite load is really tied to how loud the scrapes are.

TALITHIA WILLIAMS: By counting the parasites on over a hundred spiders, Damian found that the louder the scrape, the fewer the parasites.

DAMIAN ELIAS: So, what they're telling the female is, "I'm healthy, I'm free of parasites."

TALITHIA WILLIAMS: Next, the thump…

DAMIAN ELIAS: The thumps are probably to kind of make sure to maintain the female's attention.

TALITHIA WILLIAMS: And once they've snagged that, time to put on the moves.

DAMIAN ELIAS: So, the third leg displays serve to draw attention to these ornaments that are on the third legs, and they kind of like shake them around.

TALITHIA WILLIAMS: And depending on how bright they are, Damian thinks that these tell the female about his past.

DAMIAN ELIAS: By being able to correlate the brightness of these ornaments and the quality of their food when they were younger, you can say they're talking about developmental history and their feeding history.

TALITHIA WILLIAMS: And now for the finale…

DAMIAN ELIAS: And we have buzzes, these long tonal signals that inform the female about the male's size. So, the louder it is, the deeper it is, the more the female wants them.

So, it gets more and more intense. He might destroy the female.

Yep, get up, get up. Okay, stop. All right, get off. Get off. Get off.

TALITHIA WILLIAMS: Enough rehearsal; now for the real date.

DAMIAN ELIAS: Now we're going to use two live individuals. So, we can kind of track what the males are doing and how the females are responding to them.

TALITHIA WILLIAMS: To make sure he's right about these signals, Damian has to see how real live lady spiders respond.

DAMIAN ELIAS: You can see that the female, now, is just, like, really looking at the male, really looking at what he's trying to do.

TALITHIA WILLIAMS: For the guy, the stakes are high. They aren't just singing for their supper, they're singing to make sure they don't become supper.

DAMIAN ELIAS: When females are assessing males, they're deciding on whether they're a potential mate or whether a potential meal.

So, right now that he is buzzing, so he's getting really close, so he's really going to, kind of like wrapping up, trying to get this female to mate with him. Now he's really in the dangerous parts of the display. So, it's getting faster and faster, now he's going to make a copulation attempt.

Oh, the female right there said, "No way."

It's hard not to sort of feel sorry for that male. And it's especially the case if the male is really trying his heart out, and he gets eaten. Then I just feel absolutely terrible.

ANDRE FENTON: So, where do all these complex signals come from? It turns out what spiders are doing with all those thumps and buzzes is completely innate, they're born knowing a fixed set of sounds.

What might we find if we looked further up the food chain? For starters, it's clear what we humans do is very different. We aren't born knowing language; our brains learn it by listening to others.

This skill is called "vocal learning." And only a few other animals have it: whales and dolphins, elephants and seals, some birds and bats.

Like us, these animals have a flexible communication system. Scientists think that if ever we're going to find a communication system like ours, it's going to be in one of these.

YOSSI YOVEL (Tel Aviv University): If you enter a bat cave, you hear a cacophony. You hear thousands of individuals simultaneously shouting at each other. And you ask yourself, "Are they just shouting at each other, or is there more to it?"

TALITHIA WILLIAMS: Yossi Yovel is a bat biologist from Tel Aviv University.

YOSSI YOVEL: Bats are probably one of the most vocal and most social mammals on Earth. Since the moment we're here, they haven't shut up for a second.

What exactly is the purpose? Maybe we can say something about what exactly they are saying.

TALITHIA WILLIAMS: To understand how difficult a quest this is, watch what happens when Yossi's team records wild bats.

YOSSI YOVEL: So, this is a very sensitive ultrasonic microphone. Here on the screen you can see the vocalizations already in in real time.

TALITHIA WILLIAMS: Trouble is, there's just too much noise.

YOSSI YOVEL: Looking at this screen like this and trying to interpret what you see would be just like standing, you know, in the middle of a crowd of 500 people shouting at each other.

TALITHIA WILLIAMS: So, back at the lab, Yossi's team has created a tightly controlled mini bat colony.

YOSSI YOVEL: Welcome to my "Batcave."

So, this is a male. As you can see, bats are extremely cute. They're…some people would describe them as small puppies or small flying dog.

So, this is our controlled environment. So, if the cave we visited was like a stadium full of thousands of individuals, this is like your living room with a few friends. And I can put the camera there and monitor the full situation.

So I put him on this wall and he'll probably fly to the dark.

TALITHIA WILLIAMS: But placing bats in a controlled environment is just the first step. To crack the code of bats-or any animal for that matter-requires making a connection between action and sound. And that, as it turns out, is a real pain in the you-know-what.

LEE HARTEN (Tel Aviv University): Unfortunately, the only way to go about it is to go over a million hours of videos and just annotate.

TALITHIA WILLIAMS: First, the action: what are the bats doing?

LEE HARTEN: Generally, they're annoyed, they're really squabbling; no personal space.

TALITHIA WILLIAMS: Because bats live in close quarters, they fight a lot. So, making a database of "what's-the-fuss-about?" is key.

LEE HARTEN: This is a fight over food, basically. So the first bat is holding a food item in its mouth, and the second bat is coming to try and steal it. In this case I would enter a context, which is "fighting over food."

We see a female protesting the mating attempt by a male, and it's a failed mating attempt.

So, in this case, they're sleeping, one bat wakes up. He shifts a bit and he annoys the other bat by him.

TALITHIA WILLIAMS: It's a painstaking process, but one by one, Yossi's team creates a database over 100,000 bat spats.

YOSSI YOVEL: We did this for several months, around the clock, not missing a single vocalization. When you listen to these vocalizations, they all sound the same, but that's because you have a human brain and not a bat brain.

TALITHIA WILLIAMS: So, they turn to the next best thing: a brain of the silicon variety.

YOSSI YOVEL: We fed this huge dataset into a machine learning classifier, and if there are differences, the computer algorithm will learn these differences.

TALITHIA WILLIAMS: That is, if there is, in fact, any connection between the sounds the bats are making and what they're talking about, the computer will find it.

And after months of work…

YOSSI YOVEL: We have essentially built a simple bat translator.

TALITHIA WILLIAMS: One that can translate four different bat calls, even ones it hasn't heard before. This one is a fight over food.

This one a female saying something like "not tonight, big fella."

And this one? "Trying to sleep over here. Knock it off!"

YOSSI YOVEL: You can now take a new vocalization-a vocalization that I've just now recorded, for example, in my colony-you can feed it into this algorithm, and the classifier, now, will tell you what was the argument about, without observing it.

KLAUS ZUBERBUEHLER: It's fantastic. This is Dr. Doolittle's dream, you know, come true. You've cracked the system, and you can tell that these calls have these very distinct meanings.

TALITHIA WILLIAMS: And though they've only decoded a few bat calls, it's a start. Is it possible other animals are communicating something bigger, much bigger?

ELLEN GARLAND (University of St Andrews): I think everybody is used to hearing these beautiful, melodic, lovely songs from humpback whales, but it's not always nice to listen to.

When anyone asks me how pretty their sounds are, I'm like "wahaha."

TALITHIA WILLIAMS: Ellen Garland is a humpback whale expert from the University of St Andrews.

ELLEN GARLAND: I have always loved being by the sea and on the sea. Apparently, when I was six years old, I declared that I was going to be working with whales.

TALITHIA WILLIAMS: Whales, like bats, are vocal learners, and their songs are among the most complex forms of animal communication.

ELLEN GARLAND: A single song, typically, is anywhere from five minutes to half an hour, just for one song. So, these guys sing for hours and hours on end.

TALITHIA WILLIAMS: Like human music, whale songs consist of repeated phrases and themes, made up of individual units.

ELLEN GARLAND: On average, there's about 34 to probably 36 different sound types that we recognize within the humpback song repertoire. And we name them how they sound. So, moans, groans, grunts, whoops; so, we call that a trumpet. We have a lot of low frequency, very grunty sounds and sort of ascending shrieks, so "eeeeeeee." "Oooo oooo oooo oooo oooo."

I feel like that one is definitely going to come back to haunt me.

TALITHIA WILLIAMS: Which begs the question, "Why?" Why are whales making such complex songs? One clue might be that only the males do the singing.

ELLEN GARLAND: Humpback song is really an acoustic peacock tail. It's extremely showy and complex. They're obviously communicating with each other. You sort of want to understand why they're doing that, what they're trying to say.

TALITHIA WILLIAMS: To find out, Ellen embarked on the world's first mapping mission of whale song.

ELLEN GARLAND: I was to analyze song across the South Pacific region, to try and understand what the songs were in multiple populations for multiple years.

TALITHIA WILLIAMS: Across the South Pacific, there are tens of thousands of whales living in separate groups. Until Ellen came along, no one had ever compared their songs.

ELLEN GARLAND: There were so many songs. I couldn't keep them straight in my head, so I started to draw them. And then from there, I can actually lay them down on the floor by population, by year.

TALITHIA WILLIAMS: Next, she color-coded the songs.

ELLEN GARLAND: You can absolutely tell the difference between these song types, because they have lots of different sounds in them, and it's the particular arrangement of these sounds.

So, this is the blue song type.

Now, if we listen to the dark red song…

As you can see, this is completely different.

TALITHIA WILLIAMS: Scientists thought that at any given moment, each group only sang its own tune.

TECUMSEH FITCH: Well, we've thought for a long time that all the males in an area sing the same song, but that it's different when you go to different areas. It's different in, whatever, Hawaii from Tahiti.

ELLEN GARLAND: So, we expected to find that all the songs within a year would be the same. So, I started analyzing, and I started with the easterly population of French Polynesia. And there were some interesting irregularities in there, shall we say. And I was like, "Hmmm, this seems strange."

TALITHIA WILLIAMS: Strange, because in French Polynesia, in 2006, not all the males were singing the same song. Sometimes the whales were singing the red song, sometimes the blue.

ELLEN GARLAND: And then I went to the next population over, the Cook Islands; and then I got to Tonga; and then I got to New Caledonia, and, of course, finally to East Australia. There was sort of a disconnect.

TALITHIA WILLIAMS: The same songs kept turning up, but in different places.

ELLEN GARLAND: I talked with other researchers, and they were like, "Wow, I've seen that song type. What is it doing over there in that year?"

TALITHIA WILLIAMS: What was going on? It wasn't until Ellen mapped everything out, over time, that a picture began to emerge.

Consider the blue song. In 2002, it enters the charts in East Australia; in 2003, it's all the rage in Tonga; 2004, it's a hit in Samoa; and by 2005, it's number one in the Cook Islands. Meanwhile, back in East Australia, those trendsetters had picked up a brand new tune.

ELLEN GARLAND: All of the males threw the current blue song out the window and started singing this dark red song type.

And then, once they were singing it, it was then passed to the next population over, which is New Caledonia. And all those males learnt this brand new song type, and again and again, across the South Pacific, so to Tonga, American Samoa, the Cook Islands and finally to French Polynesia.

It's almost a game of telephone across the South Pacific.

TECUMSEH FITCH: It was kind of like Beatlemania when the, you know, the British invasion came over and transformed American music.

TALITHIA WILLIAMS: And this didn't just happen once. As Ellen dug deeper, she found that this same thing happened year after year.

ELLEN GARLAND: And that was the really big "eureka" moment.

BRENDA MCCOWAN (University of California, Davis): The fact that we see repertoires of song shifting from one population to another, across the Pacific, in humpback whales, shows that humpback whales have cultural transmission. That's a big deal, because culture was once thought to be uniquely human.

TALITHIA WILLIAMS: No one knows how these songs start, but why would male whales put so much effort into switching them?

ELLEN GARLAND: We think that it's something to do with novelty. A novel song makes you stand out against the background of singers around you. You want to be able to stand out to that female and maybe you'll get more matings.

TALITHIA WILLIAMS: But are they just sexy tunes? Could there be any lyrics?

ELLEN GARLAND: So, exact content in them, what their message is, that's still unknown.

TALITHIA WILLIAMS: Could we ever know if any information is being exchanged?

It's the same problem faced by scientists at SETI who listen to signals from space, hoping to find signs of intelligent life.

BRENDA MCCOWAN: SETI's really interested in knowing whether or not there are other beings in the universe that are intelligent. And one of the ways to do that is to quantify and understand communication.

TALITHIA WILLIAMS: So, why not start by trying to decode the "alien tongues" right here on Earth?

LAURANCE DOYLE (SETI Institute): Looking at the stars and saying, "Are we alone?" I don't think is as useful as looking at the millions of other communication systems that are nonhuman on Earth, and studying them, so that if and when an extraterrestrial signal is received, we'll have a feel for nonhuman communication.

TALITHIA WILLIAMS: Easier said than done.

ARIK KERSHENBAUM (Cambridge University): We're faced with a big problem, which is we don't have any idea what the meanings of the sounds are, so we can't translate them. We've got no Rosetta stone; we can't say, "This sound means 'fish,' and that means 'dog.'"

TALITHIA WILLIAMS: Think about it for a second.

Imagine you were an alien peering down on Earth, trying to decipher what these odd creatures had to say.

How would you know what to listen to?

This music stuff?

Laughter? Crying?

When you think about it, we humans are making lots of noise, and only a fraction of it contains information we call language. How would you be able to pick out the right parts?

Well, this is where the math comes in.

ARIK KERSHENBAUM: We're really looking for a statistical fingerprint for language. Is there something about the way that the sounds have been put together into a sequence that is characteristic of language?

TALITHIA WILLIAMS: Consider ours for a moment.

jj In 1945, linguist George Zipf asked his students to plot out the frequency of each of the 264,430 words used in James Joyce's Ulysses.

LAURANCE DOYLE: He drew a straight line through it, and it had a 45-degree, minus-1 slope.

TALITHIA WILLIAMS: Oddly, the most frequent word occurred exactly twice as often as the second most frequent word, three times as often as the third most frequent word, and so on down the line.

In the logarithmic scale that mathematicians use, it looks like this.

LAURANCE DOYLE: So, he thought, "That's interesting, what if I take another book?"

TALITHIA WILLIAMS: Darwin's Origin of Species.

LAURANCE DOYLE: Same thing. "What if I take a Chinese book?" Same thing.

TALITHIA WILLIAMS: Turns out, every human language on the planet follows this rule, from Swahili to Arabic to Eskimo. It's called Zipf's law.

BRENDA MCCOWAN: It suggests it that the structure of language is fundamentally the same, across different languages.

TALITHIA WILLIAMS: So, what about animals? Brenda McCowan at U.C. Davis and Laurance Doyle at SETI-yes, the search for extraterrestial intelligence-wanted to find out. So, they decided to analyze one of the most intelligent animals we know: dolphins. They communicate with an elaborate repertoire of whistles.

BRENDA MCCOWAN: By categorizing whistles into what we would call words, if you will. And I don't mean that literally, but the idea is to categorize signals into types.

LAURANCE DOYLE: Brenda McCowan had collected a bunch of signals and gotten their frequency of occurrence. And one morning, I got up and decided, "Well, I wonder if this obeys Zipf's law."

TALITHIA WILLIAMS: And wouldn't you know.

LAURANCE DOYLE: It obeyed Zipf's law. So, I went and had a cup of tea, and then I went back and did it again. And it obeyed Zipf's law.

BRENDA MCCOWAN: I was pretty excited. Because, I mean, it could have been anything. I mean, what's the probability that you're going to find something that is a negative-one slope in another species? It's, it's, you know, not only exciting, but seems highly improbable.

LAURANCE DOYLE: It's one of those moments in science, where you're going, "Wait a second, dolphins have a communication system with potential complexity as complex as humans." It doesn't measure meaning, but it does measure what they could be saying.

BRENDA MCCOWAN: It doesn't necessarily mean that dolphins have language. It just means that they may have a complex communication system that functions like language.

ANDRE FENTON: Which brings us to the question, "Do any animals have language?"

ARIK KERSHENBAUM: People have set up language as being really the only remaining trait that separates us from all other animals. The trouble is that language cannot be simply binary. It cannot be the case that we have language and no one else has even a part of a language. That goes against everything we know about how evolution works. So, there must be a spectrum of linguistic ability among animals.

ANDRE FENTON: And, in fact, all the research today is telling us how much we share with animals, but a huge mystery remains.

Where does language come from? Unlike our other features, like opposable thumbs or walking upright, there are no fossils for speech.

The only way to answer this question is to dive deep into the biology, into our brains, our cells and the very genes that make up you and me and every creature on Earth.

Could it be that we're not as special as we think?

ERICH JARVIS: Many people have been assuming that we're much more different than animals when it comes to language. When we start to realize the similarities, then we start to learn how we can get at this mystery of where language came from.

TALITHIA WILLIAMS: This is the question that drives Erich Jarvis at Rockefeller University. A formally trained dancer from the Bronx, he's long been fascinated by language.

ERICH JARVIS: I felt like being trained as a dancer trained me to become a scientist, because both require a lot of discipline, hard work, creativity, lots of failure before you get success.

TALITHIA WILLIAMS: And in the past 29 years, Erich has had a lot of success, but the path to get there was not easy.

ERICH JARVIS: I guess my story begins with being born here in New York City. We had what one might consider a broken family. My father, he eventually became homeless, and he was later killed by gang who were killing homeless people. So, I grew up with a single mother. We were not a wealthy family. Culturally, we were wealthy. I followed my mother's wisdom of trying to do something that has a positive impact on society, so I decided, "I'm going to become a scientist."

I had to learn that it is more difficult for me, because I didn't have much to compare to. There wasn't anybody in my family, anybody in my friend circle, anybody in my neighborhood that I knew was a scientist.

TALITHIA WILLIAMS: Nonetheless, Erich forged ahead, delving for answers about the origin of language in the brains of songbirds.

ERICH JARVIS: This mystery of where language came from, 10 years ago, we had very little clue. But now, we're at the point where we're starting to understand how language brain pathways evolve and the underlying genes that control that.

TALITHIA WILLIAMS: Little did he know, a huge clue would come from a single family.

ERICH JARVIS: When we first heard about the family, it was the first time that anybody had found any genetic change that causes something specific for speech.

TALITHIA WILLIAMS: Three generations of the Kearney family had difficulty speaking. Analysis of the family's D.N.A. led to a gene called FoxP2.

Humans with a mutation in the FoxP2 gene, who are otherwise normal, have trouble making complex sounds.

ERICH JARVIS: They can do kaa kaa kaa kaa kaa. They have trouble producing complex syllables, like "con-di-tion."

TALITHIA WILLIAMS: Songbirds also have a FoxP2 gene. And when Erich inserted the same mutation into them, they too had trouble.

ERICH JARVIS: Then the birds can't imitate properly, just like in humans. Even though we're separated by 300-million years from a common ancestor, a gene became used for a similar purpose in humans and vocal learning in birds.

TALITHIA WILLIAMS: Turns out all animals have a FoxP2 gene, but it was assumed that it only affected communication in vocal learners.

But if this were true, why would all animals have the gene? Erich wondered if its effect on communication could be more profound. So, he decided to try the same experiment in a species that doesn't learn its vocalizations, mice. They don't just squeak…

ERICH JARVIS: …they sing. When pitched down to the human hearing range, actually sound like songbird songs. It's amazing.

TALITHIA WILLIAMS: And like many songbirds, the males sing to impress the ladies.

ERICH JARVIS: Usually, when you put a female with a male he produces these complex, very modulated syllables. We call them the sexy songs.

TALITHIA WILLIAMS: But unlike songbirds, mice are born knowing their songs.

ERICH JARVIS: Our assumption was that mice are vocal non-learners, so putting this human mutation that causes a speech deficit shouldn't do anything to their vocal behavior.

TALITHIA WILLIAMS: If the FoxP2 mutation does affect mice, that would mean the roots of human language spread well beyond a handful of vocal learners.

ERICH JARVIS: So above the cage here is a microphone that detects in the ultrasonic range.

TALITHIA WILLIAMS: To find out, you need to take twin mice like these, identical in every way except the mutation. First, the normal mouse…

ERICH JARVIS: I'm going to go ahead and put him in a cage now, and see how he responds to this female. And I'm going to expect, since he doesn't have the mutation, that he's going to produce more complex songs to her. So, here we go.

There he goes. That's a complex syllable type. There he goes. See? So, like, we have these pitch jumps here, from here to here, here to here, and then these long syllables like these, followed by short ones. This is what a normal animal should be singing.

TALITHIA WILLIAMS: Now, for his brother, the mouse carrying the same mutant version of the gene that affects speech in humans and songbirds.

ERICH JARVIS: Okay, so, now I'm going to take his brother, who has the FoxP2 mutation, and I'm going to put him in the cage. So, our question is will his mutation affect his ability to produce song, and if so, how?

Here he goes, here he goes. These are more simple syllables. Simple, here you go. He's singing. So, this guy, he's behaving normally, but he doesn't seem to want to produce these more complex sequences, as we've seen in his brother.

This female she's like "ehh."

So, what you see here are sonograms of the sounds that these mice are producing, and what kind of almost looks obvious here, this is the complex song that the wild type mice sing to the female.

You take the FoxP2 mice with the mutation, instead of doing this, they do this. The simple song, where they have these simple syllables, not the same as what you're seeing in the wild type mice.

So, I'm actually even struck more about the stark contrast that I'm seeing in these two brothers, one that doesn't have the mutation and one that does. Everything else about them is the same.

TALITHIA WILLIAMS: What it means, according to Erich, is that the roots of human language run deeper than we previously thought. Even in a species that's born knowing its vocal repertoire, FoxP2 appears to affect the ability to make complex sounds.

ERICH JARVIS: And it suggests that it's not a black or white world of the haves and the have-nots; it's a continuum. And it brings us closer to these other animals, in our abilities, in our cognition, in our speech. I'm not saying we're the same. Mice and humans aren't the same; we're more advanced. But we are closer than what people realize.

BRENDA MCCOWAN: Language is like the last barrier that we seem to hold as being truly unique. So, we really sort of have to change our way of thinking about what I would call a continuum between other animals and humans.

CATHERINE HOBAITER: If we only think about human language, and we're only focusing on what might be shared between human language and communication in other species, we could be missing so much of what other species do.

PETER TYACK: I think we've discovered enough and had enough surprises to be absolutely sure that we've just scratched the surface, and that there is this amazingly complex and wonderful world to explore, which should keep generations of biologists and psychologists busy into the future.

Broadcast Credits

Talithia Williams
Rana el Kaliouby
André Fenton
Anna Lee Strachan
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Michael Bicks & Anna Lee Strachan
Michael Bicks & Anna Lee Strachan
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Scorekeeper's Music
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Kirsty Graham
The Gorilla Foundation
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Tan Morgan
University of Maryland
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Dante Graves
Lindsey Chou
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Vanessa Ly
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Caitlin Saks
David Condon
Pamela Rosenstein
Evan Hadingham
Chris Schmidt
Melanie Wallace
Laurie Cahalane
Paula S. Apsell

A NOVA Production by Little Bay Pictures for WGBH Boston.

© 2018 WGBH Educational Foundation

All rights reserved

This program was produced by WGBH, which is solely responsible for its content. Some funders of NOVA Wonders also fund basic science research. Experts featured in this film may have received support from funders of this program.

Original funding for this program was provided by the National Science Foundation, the Gordon and Betty Moore Foundation and the Alfred P. Sloan Foundation.

This material is based upon work supported by the National Science Foundation under Grant No. DRL-1420749. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.


Image credit (Chimpanzee In Forest)
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Laurance Doyle
SETI Institute
Rana el Kaliouby
Damian Elias
University of California, Berkeley
André Fenton
New York University
Tecumseh Fitch
University of Vienna
Ellen Garland
University of St. Andrews
Lee Harten
Tel Aviv University
Cat Hobaiter
University of St. Andrews
Erich Jarvis
Rockefeller University
Arik Kershenbaum
Cambridge University
Brenda McCowan
University of California, Davis
Robin Queen
University of Michigan
Jared Taglialatela
Kennesaw State University
Peter Tyack
University of St. Andrews
Talithia Williams
Harvey Mudd College
Yossi Yovel
Tel Aviv University
Klaus Zuberbühler
University of Neuchatel

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