Wild Talk

Summary

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Radiolab – "Wild Talk" (October 18, 2010)

Episode Overview

In this episode of Radiolab, hosts Jad Abumrad and Robert Krulwich embark on a journey into the world of animal communication, asking: How much language is hiding in wild animal chatter? The show investigates the “words” in nature, highlighting scientific discoveries about how creatures from monkeys in African jungles to prairie dogs on the American plains signal, warn, and perhaps even describe the world—and each other. This exploration not only questions the boundaries of human language but also the nature of communication in the wild.

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Key Discussion Points & Insights

I. Introduction – Wild Places, Wild Voices

[01:49 - 02:32]

• Jad and Robert frame the episode as an exploration of how listening closely in the wild reveals a “language” in the chaos of animal sounds.
• Robert: “There is now a group of scientists… reducing wildlife to wild talk. There are words in there.” [01:58]

II. Jungle Study: Diana Monkeys in the Ivory Coast

[02:45 - 07:19]

• Researchers: Klaus Zuberbuller (professor of psychology, University of St. Andrews, Scotland) is introduced by Ari Daniel Shapiro.
• Setting: The dense, “cathedral-like” Tai Forest in Ivory Coast, Africa, described as sensory-rich, noisy, and visually impenetrable.
  • Klaus: “Sometimes you feel like you walk through a big cathedral of dark trees...” [03:34]
• Focus: Diana monkeys, their alarming cacophony, and the quest to decode their sounds.
• Method: Klaus plays recordings of predator sounds to provoke alarm calls:
  • Leopard sound elicits one kind of alarm call.
  • Crowned eagle sound elicits a call that sounds similar to the untrained ear.
• Discovery: Subtle but consistent acoustic differences in monkey calls depending on the predator (revealed via spectrograms and, later, trained listening).
  • Klaus: “When you know what to pay attention to, you go out into the forest and suddenly you do hear these differences...” [06:58]
• Insight: Monkeys use distinct vocalizations as “words” for specific threats, prompting different escape strategies (climb up for leopards, down for eagles).

III. Prairie Dogs: The Rodent Linguists

[07:24 - 14:21]

• Expert: Kahn Slobochikoff, professor emeritus at Northern Arizona University, studies prairie dog communication.
• Observation: Prairie dogs have different “chee” calls for humans, coyotes, and dogs—but distinctions are inaudible to humans.
• Method: Computer analysis (spectrograms) teases out nuanced sound differences.
  • Jad demonstrates with sound layering: “This sound is filled with little ghost notes we can’t hear...” [10:34]
• Breakthrough: Within the “here comes the human” calls, further subtle variation hints at descriptive information (color of shirt, height).
  • Kahn: “What if they could be describing the individual humans?” [11:25]
• Experiment: Four humans dressed identically except for shirt color walk past the colony; prairie dog calls cluster by shirt color and even human height.
  • Kahn: “Essentially, they were saying, here comes the tall human in the blue versus here comes the short human in the yellow.” [12:41]
• Shape Discrimination: Prairie dogs can distinguish flying triangles (hawk-shaped) from circles and squares, possibly mapping shapes to potential threats.
  • Kahn: “Triangles kind of look like hawks. Circles and squares look like terrestrial predators.” [13:57]
• Vocabulary Extent: Their calls encode information such as species, color, size, and even shape.
  • Jad: “What you’ve got here is a little rodent with a remarkably big vocabulary...” [14:08]

IV. “Bilingualism” in the Jungle: Eavesdropping Among Species

[15:09 - 17:32]

• Big Question: Can animals “overhear” or encode meaning from the calls of other species, like humans picking up on a foreign conversation?
  • Robert: “Is there an equivalent of listening to the other person talking French in the wild?” [15:43]
• Klaus’s Experiment: Diana monkeys and Campbell’s monkeys live alongside many other primate species in the Tai forest.
  • Alarm calls of one species (e.g., Campbell’s monkeys) are played for another (Diana monkeys). Result: Diana monkeys respond correctly to the alarm, indicating cross-species understanding.
  • Klaus: “To our great surprise…they understand it... they take that very, very seriously and respond to it very strongly.” [16:52]
• Beyond Monkeys: Even birds (yellow-casked hornbills) key into these primate alarm calls; an intricate communication web exists.
  • Klaus: “It’s a pretty substantial web of species basically eavesdropping on each other’s calls.” [17:23]

V. Becoming Part of the Wild Conversation

[17:34 - 21:11]

• Klaus recounts a personal, transformative moment in the forest:
  • Walking alone, he hears Diana monkeys issuing sequential leopard calls, tracking his path.
  • He realizes the monkeys are warning of a stalking leopard.
  • Klaus: “I was suddenly able to understand what the monkey’s trying to say, so to speak.” [18:25]
• The experience shifts him from observer to participant, “the 11th primate,” in the web of communication.
  • Klaus: “Suddenly, I shifted from being the objective observer to being, you know, sort of part of that whole crowd in there.” [20:17]
• Emotional resonance: Despite 20–30 million years of evolutionary divergence, he feels “taught” by the humble creatures—highlighting both the divide and the fleeting connections possible between species.

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Notable Quotes & Memorable Moments

• Robert Krulwich: “It’s really kind of like a word. It’s like a word—that’s kind of amazing.” [07:19]
• Kahn Slobochikoff (on individuality in prairie dog calls): “Oh, I was astounded. I was astounded.” [12:20]
• Klaus Zuberbuller: “So it’s a pretty substantial web of species basically eavesdropping on each other’s calls in these forests.” [17:23]
• Klaus Zuberbuller (on becoming the 11th primate): “Suddenly, I shifted from being the objective observer to being, you know, sort of part of that whole crowd in there.” [20:17]
• Kahn Slobochikoff (on prairie dog “chatter”): “Could be just simply chatter, chitter, chitter. Or it could be, do you know where Sam was last night?” [14:31]

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Important Segment Timestamps

• [02:45] — Introduction of Ari Daniel Shapiro and Klaus Zuberbuller; setting the jungle scene
• [05:10] — Playing predator sounds and observing Diana monkey responses
• [06:44] — Discovery of nuanced alarm calls as unique “words”
• [07:51] — Transition to prairie dog story with Kahn Slobochikoff
• [11:25] — Realization that prairie dogs may describe individual humans
• [13:00] — Experiment with flying shapes over prairie dog colony
• [15:43] — Discussion of “wild eavesdropping” and cross-species communication
• [16:46] — Diana monkeys’ understanding of Campbell’s monkeys’ alarm calls
• [17:34] — Klaus’s dramatic encounter with a (stalking) leopard, signaled by monkey alarm calls
• [20:17] — Emotional reflection on becoming part of the forest’s communication network

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Episode Takeaways

• Animal “language” is more complex and nuanced than previously assumed, encoding not just warnings but potentially descriptions and identities.
• Different species, and even different classes of animals (such as birds and primates), can eavesdrop and interpret each other’s alarm calls, building a shared web of meaning in the wild.
• Interpreting and being part of this wild conversation can be a profound and humbling experience, reminding listeners of the evolutionary ties and differences that connect and separate all living things.
• Radiolab’s tone balances scientific rigor with wonder, curiosity, and humor—inviting listeners to join in the adventure of decoding the wild.

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Transcript

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[Jad Abumrad]

Wait, you're listening. Okay.

[Ari Daniel Shapiro]

All right.

[Robert Krulwich]

Okay.

[Jad Abumrad]

All right. You're listening to Radio Lab.

[Klaus Zuberbuller]

Radio Lab shorts from wnyc.

[Robert Krulwich]

Yes.

[Listener]

And npr.

[Jad Abumrad]

Hey, I'm Jad Abumrad.

[Robert Krulwich]

I'm Robert Krulwich.

[Jad Abumrad]

This is Radiolab, the podcast. The podcast. And in this podcast, I don't know, how would you describe this one?

[Robert Krulwich]

My sense is that you walk into a wild place and you hear the wind and the trees and you hear these chirps and sounds and calls and they're just part of the they're part of the wild. They're wildlife. But there is now a group of scientists who listen to much more closely and who are reducing wildlife to wild talk. There are words in there.

[Jad Abumrad]

When you find the words, as the people we will meet do in these stories, you end up not just understanding, but actually entering that wild space in a very cool way.

[Robert Krulwich]

So we're going to tell you two tales here.

[Jad Abumrad]

Two different places. The first a jungle and the second a prairie. Right? Jungle gets us started and then the prairie later. This is a story, this first one that we heard about.

[Ari Daniel Shapiro]

Yeah, yeah, from Ari. I'm Ari. Daniel Shapiro. I'm a public radio producer in Boston.

[Jad Abumrad]

Ari recently met a guy, I think a German guy.

[Ari Daniel Shapiro]

He's Swiss. Oh, okay. So, yeah, his name's Klaus Zuberbuller.

[Klaus Zuberbuller]

Hey, Ari. It's Klaus.

[Ari Daniel Shapiro]

And he's a professor of psychology at the University of St. Andrews, which is in Scotland.

[Jad Abumrad]

And where does this story actually take place?

[Robert Krulwich]

Because where's the jungle?

[Jad Abumrad]

Yeah.

[Ari Daniel Shapiro]

Well, maybe the best place to start is to kind of describe the scene where we are, which is in the Thai forest. Thai forest, which is in the Ivory coast, in Africa.

[Robert Krulwich]

So it's not in Thailand.

[Ari Daniel Shapiro]

No, it's not. It's Tai Tai. Okay. Yeah. And Klaus describes the jungle as this thick sensory world, very dark, very moist.

[Klaus Zuberbuller]

And very, very green.

[Ari Daniel Shapiro]

And you can't really see for more than 15 to 20ft.

[Klaus Zuberbuller]

And, I mean, sometimes you feel like you walk through a big cathedral of dark trees and you don't see very much because all the animals obviously very shy and run away.

[Ari Daniel Shapiro]

I mean, is it still.

[Klaus Zuberbuller]

No, it is very, very noisy.

[Ari Daniel Shapiro]

It's a din. It's just this kind of sonic chaos. Chaos.

[Klaus Zuberbuller]

All these insects and birds and bats and mammals. It's almost as if they compete for acoustic space. So it is very, very loud. I mean, the main sensation you have in the beginning, meaning really, is that you're just completely lost.

[Ari Daniel Shapiro]

So it's 1991, and they figured he had to start somewhere, so he focused his attention on a kind of monkey, very beautiful monkey, I think, called the Diana monkey.

[Klaus Zuberbuller]

It's a mix of black, white, and sort of reddish.

[Ari Daniel Shapiro]

Diana monkeys live up in the treetops, which can be as high as 100ft off the ground.

[Listener]

Wow.

[Ari Daniel Shapiro]

They eat fruits and they eat insects, and they're chattering.

[Klaus Zuberbuller]

Cacophony of calls.

[Ari Daniel Shapiro]

Which to him, of course, you know, as a newcomer to the forest, was all just noise.

[Klaus Zuberbuller]

It's a little bit, I imagine, like a child trying to learn a language, which initially must just sound like a string of sounds that he can't really understand. And then, you know, what.

[Jad Abumrad]

So what did he do?

[Ari Daniel Shapiro]

Well, he started provoking the monkeys into making different kinds of noises. For instance, he'd walk out into the forest with a boombox and play the sound of the Diana monkey's most feared predator, the leopard.

[Jad Abumrad]

He would just play the sound into the trees.

[Ari Daniel Shapiro]

Yep. And all of a sudden, they start leaping around the branches, hopping around.

[Klaus Zuberbuller]

Motion.

[Ari Daniel Shapiro]

And they make this one particular call.

[Klaus Zuberbuller]

You know, these very loud alarm calls.

[Ari Daniel Shapiro]

This one here.

[Robert Krulwich]

Meaning what?

[Jad Abumrad]

Yeah, Are they just saying, like, run, or is it something more specific?

[Ari Daniel Shapiro]

Well, here's where it gets a little bit more interesting. Next step, he brought that same cassette.

[Jad Abumrad]

Player out, pointed at the trees, hit play.

[Ari Daniel Shapiro]

All that. Yep. But this time he plays the shrieks.

[Klaus Zuberbuller]

Of a crowned eagle.

[Jad Abumrad]

Eagles eat monkeys.

[Ari Daniel Shapiro]

Yeah, they do.

[Klaus Zuberbuller]

They attack from above about them.

[Robert Krulwich]

They're very scary. They come flying in with their talons or their beaks, and they hit you in the head sharply and kill you instantly. And then you fall to the ground.

[Ari Daniel Shapiro]

Yeah.

[Jad Abumrad]

And so what do the monkeys do when they hear this?

[Ari Daniel Shapiro]

They make that sound.

[Jad Abumrad]

Same one.

[Ari Daniel Shapiro]

Well, that's what he thought. But when he went back to the lab and started looking at the sounds on the computer, comparing one to the other, eagle, leopard, eagle, leopard. He realized that they're actually slightly different.

[Klaus Zuberbuller]

In the acoustic details of the calls. And it's something that is very difficult to hear when you really only see it in the spectrogram, which is kind of a visual representation of these calls.

[Jad Abumrad]

This is on the computer?

[Ari Daniel Shapiro]

Yeah.

[Klaus Zuberbuller]

But interestingly, once you've seen that and once you know what to pay attention to, you go out into the forest and suddenly you do hear these differences, which you haven't heard before.

[Robert Krulwich]

So you're saying when they hear a call, leopard coming, they go up the tree, but when they hear eagle coming, they run down the tree.

[Ari Daniel Shapiro]

Exactly, exactly.

[Robert Krulwich]

So it's really kind of like a word. It's like a word that's kind of amazing.

[Jad Abumrad]

Let's pull out for a second. Because this guy actually got us thinking, honestly, how much language actually is out there in the wild? Like, what do we know? What's the state of what we know right now? And that question led us out of the forest just for a second, and to a place and a creature we just didn't think would be a part of this conversation at all. And that creature is the prairie dog. Prairie dogs.

[Robert Krulwich]

So here's the thing. Prairie dogs are these little rodent like animals. They live under the ground in burrows, and when their community is invaded, they pop out of the burrow and they say, oh, here comes the whatever.

[Kahn Slobochikoff]

Sounds kind of like chee chee, chee, chee, chee, chee, chee, chee.

[Jad Abumrad]

So we spoke with this guy.

[Kahn Slobochikoff]

My name is Kant Slobochikov, professor emeritus at Northern Arizona University, who spent a.

[Jad Abumrad]

Whole lot of time sitting out in the colonies recording prairie dog calls. And he now believes that these simple little rodents are like nature's wordsmiths.

[Kahn Slobochikoff]

Well, the thing is that initially I.

[Jad Abumrad]

Recorded, for instance, he began by telling us that the prairie dogs have different.

[Kahn Slobochikoff]

Kinds of cheese for different kinds of predators. For example, humans, coyotes and dogs. Right.

[Jad Abumrad]

Is this the kind of thing that we would actually be able to hear the difference between the calls?

[Kahn Slobochikoff]

I'm guessing that you could hear the difference.

[Robert Krulwich]

You want to try it, Chad?

[Ari Daniel Shapiro]

Yeah.

[Jad Abumrad]

Soren, could you just play those samples? All right, so here's one.

[Klaus Zuberbuller]

This is another one.

[Jad Abumrad]

All right, here you go.

[Fidelity Disclaimer]

This is a third.

[Jad Abumrad]

Those represent different predators.

[Kahn Slobochikoff]

Yep.

[Robert Krulwich]

I can't tell the difference.

[Jad Abumrad]

Can you? I mean, do you know what they are?

[Kahn Slobochikoff]

My guess is human, dog, coyote.

[Jad Abumrad]

Kahn was right.

[Robert Krulwich]

Khan was right.

[Jad Abumrad]

Wow.

[Robert Krulwich]

Well, naturally we wondered, how did he.

[Jad Abumrad]

How did he do that?

[Robert Krulwich]

Yeah, he told us that at first, just like you and I, he couldn't figure out how to distinguish between these sounds. But he took the sound back to.

[Kahn Slobochikoff]

The lab where we had a machine that allowed us to measure a series of frequency and time elements in the call.

[Robert Krulwich]

And what this computer does is it takes the sound that the prairie dogs make, and it essentially looks inside for the ingredients inside the sound.

[Jad Abumrad]

Yeah, like. Well, it's kind of hard to hear with a chirp because it's just hard. So let me demonstrate crudely with this other sound. I plucked this at random from my library. So this is kind of like a buzz.

[Robert Krulwich]

Okay.

[Jad Abumrad]

Okay. Let me just loop it so we can hear it better. So here you've got this buzz, which is sounds to us like a solid piece of noise. But get an EQ and take away all the highs. So now you've got just the bass.

[Robert Krulwich]

Yep.

[Jad Abumrad]

Now you'll notice that if you add the highs back in real slowly, these little hidden overtones will pop out. Like, there's one. Yeah, there's another third.

[Robert Krulwich]

Yep.

[Jad Abumrad]

Fourth.

[Robert Krulwich]

Uh huh.

[Jad Abumrad]

So in other words, this sound is filled with little ghost notes that we can't hear. And certainly the same is true of this sound. Except in the case of the prairie dogs, it seems their ears are tuned to hear all the different sounds within. The chirp probably sounds to them like.

[Ari Daniel Shapiro]

This whole layer cake of tones.

[Robert Krulwich]

And Kahn's computer noticed that the noise they made when a human walked through their village was different in tone from the noise they made when a coyote walked through their village. It was consistently different.

[Kahn Slobochikoff]

But there was a problem when he.

[Robert Krulwich]

Zoomed in on the, oh, here come the human calls. These ones here.

[Jad Abumrad]

And he looked at them really closely. He saw that from one human call to the next, there was a lot of subtle variation.

[Kahn Slobochikoff]

Much, much more than I would expect.

[Robert Krulwich]

And that's when it hit him, what.

[Jad Abumrad]

If, what if, what if?

[Kahn Slobochikoff]

What if they could be describing the individual humans?

[Robert Krulwich]

Oh.

[Kahn Slobochikoff]

Now, at that time, no one suspected that this might even be a possibility, but I thought, well, let's try it and see what happens.

[Jad Abumrad]

So Kahn recruited four humans, and he.

[Robert Krulwich]

Had them dress exactly the same. Same boots, same blue jeans, same sunglasses, Everything the same, except the color of their shirts.

[Kahn Slobochikoff]

We had person in a blue T shirt, person in a green T shirt, person in a yellow shirt, person in a gray shirt.

[Jad Abumrad]

Then he asked each of them to walk through the prairie dog village.

[Robert Krulwich]

One by one.

[Jad Abumrad]

Prairie dogs made their chirps.

[Kahn Slobochikoff]

And when we analyzed the results, there were significant differences.

[Jad Abumrad]

Like what kind?

[Kahn Slobochikoff]

They essentially clustered around the colors.

[Robert Krulwich]

Does that mean you think you can hear them saying, here comes the human in blue.

[Kahn Slobochikoff]

Right.

[Robert Krulwich]

Versus here comes the human in yellow.

[Kahn Slobochikoff]

Right.

[Ari Daniel Shapiro]

Really?

[Kahn Slobochikoff]

Oh, I was astounded. I was astounded.

[Robert Krulwich]

He was like, well, wait a second. These humans, they're not just different in their shirt colors. They're different in all kinds of ways.

[Kahn Slobochikoff]

Some of the humans were taller. Some of the humans were shorter.

[Jad Abumrad]

So we went back, reanalyzed the chirps, looked a little more closely, and he realized we could tease out the prairie dogs were also commenting about the general.

[Kahn Slobochikoff]

Size of the human. Essentially, they were saying, here comes the tall human in the blue versus here comes the short human in the yellow.

[Robert Krulwich]

Wow.

[Jad Abumrad]

And then he made another leap.

[Kahn Slobochikoff]

And it was just, you know, since he was on a roll off the wall idea at that time, he went.

[Robert Krulwich]

Back into the prairie dog field, and he built two large wooden boxes sitting.

[Kahn Slobochikoff]

On stilts a good distance from each other, 150ft. And we strung wires between the two towers.

[Robert Krulwich]

His team then made cardboard cutouts of three different shapes.

[Kahn Slobochikoff]

A circle, a square, and a triangle.

[Robert Krulwich]

And then they ran them out along the wire, kind of like laundry fluttering above you in the breeze.

[Kahn Slobochikoff]

Each shape would emerge from one of the tower blinds and fly something like about three feet over the prairie dog town.

[Jad Abumrad]

So literally, you would just kind of go, and out would come a triangle or a circle or a square.

[Kahn Slobochikoff]

Correct. And what we found was that the prairie dogs could tell the triangle from the circle very easily, but they could not seem to tell the difference between a square and a circle.

[Robert Krulwich]

Huh.

[Jad Abumrad]

Why not?

[Kahn Slobochikoff]

Well, my guess is that triangles kind of look like cocks. Circles and squares kind of look like terrestrial predators.

[Jad Abumrad]

Nonetheless, what you've got here is a little rodent with a remarkably big vocabulary, including, but probably not limited to short, fat, skinny, tall, blue, green, yellow, gray, coyote human Hawk, triangle and or square.

[Ari Daniel Shapiro]

Yay.

[Jad Abumrad]

Not bad.

[Robert Krulwich]

Is the next step that you're going to perform a scene from the Winter's Tale and see whether the prairie dogs laugh at the right moments. What do you do next?

[Kahn Slobochikoff]

Well, we just are scratching the surface of looking at this. For example, prairie dogs have a lot of calls which we call social chatters. One prairie dog will be feeding and suddenly lift up its head and go, chitter, chatter, chitter, chitter. And another prairie dog somewhere across the colony will lift up its head and go, chatter, chatter, chitter, chitter. But what does it mean we have no way of getting at? Could be just simply chatter, chitter, chitter. Or it could be, do you know where Sam was last night?

[Robert Krulwich]

Now, here's an interesting question. I mean, if a French couple were sitting next to me on the subway and they were saying, do you know where Sam was last night? In French. If I don't speak French, I'm outside of that conversation. But a lot of people do speak French and they can listen to French people talking. The question's then raised. If you live in the forest and you speak chimp or you speak eagle or you speak snake, would you ever be able to overhear or learn something from a neighborly species? In other words, is there an equivalent of listening to the other person talking French in the wild?

[Jad Abumrad]

Hmm, good question.

[Robert Krulwich]

And that brings us back to Klaus. You remember Klaus?

[Jad Abumrad]

Yeah, the monkey guy.

[Ari Daniel Shapiro]

Yeah, the monkey guy. Well, Klaus was wondering the same thing.

[Jad Abumrad]

And that's re Daniel Shapiro again, who introduced us to Klaus.

[Ari Daniel Shapiro]

So take those alarm calls for instance. He wanted to know whether different species of monkeys could understand each other.

[Klaus Zuberbuller]

Right.

[Ari Daniel Shapiro]

So, and luckily for Klaus, there's like at least 10 different primate species living inside that Thai forest. So there is one, colobus monkeys, two.

[Klaus Zuberbuller]

Spot nosed monkeys, three.

[Ari Daniel Shapiro]

Chimpanzees, four.

[Klaus Zuberbuller]

Galagos colobines, six.

[Ari Daniel Shapiro]

Honeynose monkeys, seven.

[Klaus Zuberbuller]

Mangabe species, eight. Pro simians, nine.

[Ari Daniel Shapiro]

Campbell's monkeys, and then the Dianas, 10.

[Klaus Zuberbuller]

Yeah. So it's a very, very rich primate fauna.

[Ari Daniel Shapiro]

So, Klaus, question was, could Diana monkeys understand the alarm calls of another of these monkeys, the Campbell's monkey?

[Jad Abumrad]

Could they go across monkey lines, so to speak?

[Ari Daniel Shapiro]

Exactly. So he used that same setup from.

[Jad Abumrad]

Before, the speaker thing where he plays the sound onto the trees.

[Ari Daniel Shapiro]

Yeah. And he played the eagle and leopard alarm calls from the Campbell's monkeys to the Dianas to see if they'd react.

[Klaus Zuberbuller]

And what we found there, to our great surprise, was that the Diana monkeys, they understand it.

[Jad Abumrad]

Really?

[Robert Krulwich]

Really.

[Ari Daniel Shapiro]

Yep.

[Klaus Zuberbuller]

They take that Very, very seriously and respond to it very strongly.

[Ari Daniel Shapiro]

So a Diana monkey hearing a Campbell's eagle alarm call will respond as though there were an eagle and will respond to the leopard alarm call as though there were a leopard, and vice versa.

[Klaus Zuberbuller]

And it doesn't stop there.

[Ari Daniel Shapiro]

Klaus started playing the monkey calls to birds such as hornbills, yellow casked hornbills. It turns out that they understand it, the birds.

[Jad Abumrad]

Yeah.

[Klaus Zuberbuller]

These hornbills are capable of discriminating these different monkey alarm calls.

[Robert Krulwich]

Wow.

[Klaus Zuberbuller]

So it's a pretty substantial web of species basically eavesdropping on each other's calls in these forests.

[Ari Daniel Shapiro]

But Klaus himself, he was still on the outside of it all.

[Klaus Zuberbuller]

It is that general sense of perhaps not really belonging there.

[Ari Daniel Shapiro]

But then he told me about this.

[Klaus Zuberbuller]

One day, I was working in the forest.

[Ari Daniel Shapiro]

He had gone out for the day, and he had gone out alone and.

[Klaus Zuberbuller]

Was very far away from camp.

[Ari Daniel Shapiro]

And it was in the late afternoon, and he realized that he should probably be heading back to camp because I.

[Klaus Zuberbuller]

Still had to walk for something like 15, 20 kilometers back to camp.

[Ari Daniel Shapiro]

And he was walking past a kind of valley.

[Klaus Zuberbuller]

And then I heard, on the other side of the valley, a monkey group giving leopard alarm calls, which doesn't happen that often.

[Ari Daniel Shapiro]

It was the first time that he wasn't actively listening, but he heard these monkeys make this call and recognized it.

[Klaus Zuberbuller]

He was absolutely striking.

[Ari Daniel Shapiro]

And he was actually quite excited by.

[Klaus Zuberbuller]

This because I was suddenly able to understand what the monkey's trying to say, so to speak.

[Ari Daniel Shapiro]

Those monkeys had picked up a leopard.

[Robert Krulwich]

Right beneath that sound there.

[Ari Daniel Shapiro]

The leopard would be right. But, you know, those monkeys were way across the valley.

[Klaus Zuberbuller]

So I didn't really think that much, and walked on perhaps, you know, half a mile further down the road.

[Ari Daniel Shapiro]

And the next group of Diana monkeys, still across the valley, started giving leopard.

[Klaus Zuberbuller]

Alarm clocks as well.

[Ari Daniel Shapiro]

And he kind of took notice of that. And then it happened a third time a few minutes later.

[Klaus Zuberbuller]

What became clear to me very rapidly is that a leopard was.

[Ari Daniel Shapiro]

Tracking him.

[Klaus Zuberbuller]

Of course, I couldn't see it because it was dense forest, but I assumed that the leopard saw me. And of course, that is just one of these moments where you're totally alone far, far away from camp.

[Robert Krulwich]

What does he do?

[Ari Daniel Shapiro]

He kept walking. It happened a fourth group called Leopard, fifth group called Leopard, and then the group stopped calling.

[Klaus Zuberbuller]

The only thing I could think of is to pick up a large branch.

[Jad Abumrad]

I shouldn't laugh. That's terrifying.

[Ari Daniel Shapiro]

Klaus, would that stick have done anything for you?

[Klaus Zuberbuller]

I doubt I really would have been able to do very much with a stick.

[Ari Daniel Shapiro]

But as he's standing there, stick in hand, he realizes he's just entered the forest.

[Klaus Zuberbuller]

He's become the 11th primate.

[Ari Daniel Shapiro]

The 11th primate because there are those 10 other species of primate. And now me.

[Klaus Zuberbuller]

Suddenly, I shifted from being the objective observer to being, you know, sort of part of that whole crowd in there. Even though, you know, we're separated by 20, 30 million years of evolutionary history. You know, these humble creatures, you know, were able to teach me something about, you know, what was going on in the forest. And of course, it wasn't intentional. They weren't trying to inform me or anything like that, but it was a very emotional experience.

[Jad Abumrad]

So what happened? I mean, obviously he didn't get an eaten. What happened?

[Ari Daniel Shapiro]

Well, he. He made it back to camp and he's not sure what happened to the leopard. The leopard must have slinked off into the forest. In the end, it became just another.

[Klaus Zuberbuller]

Story to tell each other over beers in the evening, I suppose.

[Jad Abumrad]

Yeah, yeah, yeah.

[Robert Krulwich]

Thanks for that story to Ari, Daniel.

[Jad Abumrad]

Shapiro, our correspondent, and also thanks to Klaus Zuberbuller and Khan Slobochikoff. I'm Jad Abumrad.

[Robert Krulwich]

I'm Robert Grillwood.

[Jad Abumrad]

Thanks for listening.

[Cassandra Williard]

This is Cassandra Williard, a Radiolab listener in Brooklyn, New York. Radiolab is supported in part by the Alfred P. Sloan Foundation, Enhancing public understanding of science and technology in the modern world. For more information about Sloan, go to. Let me start over. More information about [e-mail]. end of message.