Episode 2 Talk to the Animals

From the loudest roar...

to the smallest squeak,

all across the world, animals are talking to each other

in extraordinary ways.

Ever since I was little, I've wanted to become a real-life Dr Dolittle

and talk to the animals.

I think it's something we'd all secretly love.

I'm Lucy Cooke, a zoologist on a quest to crack the animal code.

New discoveries are being made all the time

and I'm going on a worldwide journey to unravel animal conversations

and hopefully unlock some of the secrets of their lives.

'Using the latest scientific findings,

'I'm going to listen in on a hidden world...'

(My heart is going like the clappers.)

'..from seismic chatter...'

LOW BUZZING

He's making that noise to attract her, is he?

'..to flirting in the language of light.'

I'm not just having a conversation,

I'm chatting it up!

I'll discover how animals communicate...

This is the first example we know of of infrared communication.

..and reveal exactly what they're saying.

This is amazing! So this is a dolphin greeting.

It's a totally secret world that I'm just listening in to.

'Last time, I travelled across three continents

'to find out how animals communicate

'with their families and social groups...'

The sounds they make, it's extraordinary.

'..and make contact with potential partners.'

That's unrequited love like I have never seen before.

'So what I want to learn next is how animals communicate with

'and about their enemies.'

My first stop is Kenya, East Africa.

I've come to meet an animal who has perfected the art of raising

the alarm and calling in reinforcements...

the spotted hyena.

Often depicted as a cowardly scavenger,

the laughing hyena is in fact

one of the most successful predators in Africa.

I love hyenas.

They're unfairly maligned because they are really, really smart,

intelligent animals.

'Dr Sarah Benson-Amram works with a team who have been studying

'the hyenas here for 25 years.'

Tell me how their society works.

They live in large clans and they all defend a communal territory,

but you don't always find them all together at the same time.

Hyenas stick together closely at night,

but during the day, they tend to be more spread out.

So how do they rally the troops if their territory comes under attack?

You might hear some whoop vocalisations

that can travel up to 5km.

Hyenas can also distinguish individuals based on their whoop.

So from, like, 5km away, a hyena can hear the sound

of another hyena's whoop and recognise who that individual is?

-Exactly.

-That's amazing! Gosh.

The whoop is one of the most common sounds hyenas make

and can mean different things depending on the situation.

To see what role it has in recruitment, we're going to play

the sounds of their two main enemies, lions and rival hyenas.

So we've located a lone female hyena and we're now going to play her

the sound of some stranger hyenas fighting a lion

and see what her response is.

What we hope is going to happen is that she will start whooping

in order to recruit her fellow clan to try and see them off.

RECORDING OF ANIMAL CALLS

The sounds quickly get her attention...

RECORDING OF ANIMAL CALLS

..and before long...

she calls for reinforcements.

HYENA WHOOPS

-That's fantastic! She did it - she started whooping!

-She did.

So what she's doing is now she's shouting,

"Come join me, everyone, come join me."

Other clan members have heard the whoop and come straight to her aid.

Oh, now we have a third.

So basically, she's now trying to rally the troops

-to go and see off the lions.

-And the other hyenas.

That was a really fascinating response.

Once the troops have been gathered,

the next step is to assess the threat.

Sarah's found a way to demonstrate just how much information hyenas

can deduce from the sound of each other's whoops.

What we're going to do is we're going to play the sound

of three hyenas doing their whoop call,

but these are three hyenas that this clan doesn't know.

What do we hope will be the reaction?

We've seen at least six adult hyenas here, so what we hope will happen

is that they'll pay attention to the calls, recognise that there are

three different individuals calling, know they have the bigger group

and then act aggressively,

knowing that they could take on this smaller group of intruders.

-What you're implying is that hyenas can count.

-Yes.

They have to know that, "We've heard three voices

"and now that we are six, so we should be able to take these three."

Wow! Well, that's hopefully what's going to happen

if they've read the manual.

-So we're now going to sort of launch an enemy attack.

-Yes.

Right, OK.

RECORDING OF HYENAS WHOOPING

Her head came up.

RECORDING OF HYENAS WHOOPING

Definitely got some interest now. Different hyena call.

They're all looking up now.

Every single hyena is looking at us.

Oh, my word, they're coming towards us.

They're all coming over. Wow.

'This time, there's no attempt to call for help.

'This group have worked out that they outnumber their rivals

'and are keen to press home their advantage.'

And now they're searching the area looking for the intruders.

So that clearly demonstrates that these hyenas recognise that the

calls that we played were strangers, they weren't from their clan.

And they also worked out that there were few enough calling

that they could take them on.

The hyenas have evolved the ability to work as a team to fight off threats

and they're not the only ones.

It's a trait that's seen across the animal kingdom,

but the most striking examples of this behaviour are found in birds.

Known as mobbing, flocks have been known to take on animals

hundreds of times their size...

..allowing them to see off predators they could never defeat alone.

I want to find out more about these winged armies so I've left Africa behind

and have come to the Tahoe National Forest in California.

I'm here to meet a bird who cannot only call for backup,

but can articulate precise levels of danger...

the mountain chickadee.

Carrie Branch is going to help me listen in on them.

BIRDS CHIRP

-Hey, Carrie.

-Oh, hi!

-Nice to meet you.

-Nice to meet you.

-I've seen a few chickadees about.

-Yes.

-They're quite unassuming little birds, aren't they?

-Yes, they are.

I mostly love them because I love small, angry animals

and I think of them as, like, almost the real Angry Birds.

They're quite feisty and they have quite a bit of personality.

They're always aware of predators that are lurking around,

so if you come close to them, they want to check you out

and see what you're about, as we do.

So what's the call that we're going to listen to today?

The call we're looking at today is what is known as a mobbing call.

That's because when predators are present and they're perched nearby,

what the birds do is they call a lot, just over and over again

and the notion is that they're trying to recruit other individuals

to help scare this predator away.

Carrie believes that the chickadees can adapt their mobbing calls

depending on the level of threat.

But to see this in action, we need to find some test subjects.

If you look through your binoculars, you can see the entrance.

Oh!

-So their babies are inside there?

-Yes.

-How old are they?

These guys are about 18 days after hatch.

Does that make the parents especially protective?

For sure.

We're going to present this family with two different levels of threat

and record their responses to see how they compare.

The first danger they'll face...is me.

-BIRDS CALL LOUDLY

-Oh!

Both Mum and Dad are both calling.

They're really plucky little birds, these.

Definitely, definitely telling me to leave.

Well, I've got my recording so I'm going to leave them in peace now

so they can feed the young.

While the chickadees have a well-earned lunch break,

I prepare for phase two of the experiment.

It's time to up the ante.

OK, Carrie, so this is the bigger threat.

-Right.

-What is it? Show me what you've got.

All right, so the bigger threat than you is...

-Oh!

-..Harry the Cooper's hawk.

-OK, that's a bigger threat than I am?

-Oh, yeah, definitely.

See, these birds are small, so actually smaller predators

are more threatening to them than larger predators are.

To a chickadee, small equals agile,

so these birds pose the biggest threat to them and their chicks.

But will a greater threat produce a different call?

BIRDS CALL LOUDLY

Wow, that's quick, there's two of them already.

-And what do you think they're saying?

-They're probably saying,

"Holy crap! There's a big hawk right there in front of our nest."

BIRDS CALL LOUDLY

You can hear that this is more of a response than when I came along.

This is a more aggressive mobbing call. This is a loud call.

Responses recorded,

Carrie wants to show me exactly how the two reactions differ.

Tell me, what are we looking at here?

So here we're looking at two different chickadee calls.

We have the response from the hawk presentation

and then we also have the response from the Lucy presentation,

where you were present in front of the nest box.

'The chickadee is named after its distinctive call,

'which is made up of four parts.'

Are these the different individual notes here?

Right, so these are the different note types.

Note A, note B, note C and then note D.

And as you see, we have four D notes from the hawk presentation

and then we have the same structure here

from the response from your presence.

We're got the A, B and C, but then you see we only have one D note.

Let me listen to that hawk call first, then.

CHICKADEE ALARM CALL PLAYS

So that's the hawk call. Then here we have the Lucy call.

SHORTER ALARM CALL PLAYS

It's actually really clear,

you can hear with the hawk, it's "chicka-dee-dee-dee-dee."

Basically, they're saying, "We really need some help right now,"

instead of, "Well, somebody's here, maybe some other birds

"should come and help us out."

More Ds means more danger,

it's like a kind of exclamation mark, basically?

Right, this is, like, extreme.

So this tiny creature can not only warn others of danger

but by changing the number of D notes, it can articulate exactly

the level of threat that's faced.

Carrie's research has found that

the great grey owl gets two D notes,

while the pygmy owl, despite being a quarter of the size,

is worth an enormous 23 Ds.

But the chickadees' chatter doesn't end there.

Whilst only the D notes have been decoded so far,

they can vary the number of any of the four parts that make up their call.

This system allows the chickadees to encode a huge amount of information

and the resulting sequences

have even been compared to human sentences.

I've learnt that animals have warning systems more sophisticated

than I ever thought possible.

Back in Africa, at Kenya's Diani Beach,

I'm about to meet a creature who takes things one step further.

This is a vervet monkey and it's a relatively common species

found throughout Southern and Eastern Africa,

but what's special about it is its place in scientific history.

Back in the 1980s, a couple of pioneering field scientists

started an investigation into the vervet's sophisticated alarm calls.

As I've seen, when threatened by a predator,

animals often sound the alarm.

But scientists have found that vervets are able to articulate

not only the type of threat but, incredibly, how best to avoid it.

I want to see this in action.

First of all, I need some predators.

Traditionally, the vervet has three main predators...

snakes, who hunt by stealth,

birds of prey, which can spot a vervet from over 5km away

and leopards, who can climb trees

and could devour an adult vervet whole.

Getting their real predators to play ball might be problematic,

so I'm going to try and trick the vervets with some fakes.

One of the vervet's major predators is the leopard

but there haven't been any leopards around here for decades,

so I'm going to have to improvise.

-How much is your leopard?

-30,000.

30,000? Ooh...

Don't have that much. I'm wondering, can I rent it?

-2,000 for half a day?

-Yes.

-Yeah?

-It's a deal?

-It's a deal.

Thanks, Martin.

The question is,

will the vervets have any reaction at all to my garden ornament?

VERVETS JABBER

I've just arrived and I think it's working.

Already, I've got vervets alarm-calling at my leopard.

VERVETS JABBER

Well, this is fantastic.

I didn't actually think this was going to work

because the vervets here have never seen a leopard

and that means to me that they must be pre-programmed to do this call.

But alongside the distinctive calls, I notice something else.

They're all doing the same thing.

They're running towards the end of the branches and that's because

they know that leopards can't chase them to the end of the branches

and catch them, so that's the place they're safest.

Whether this call is the monkeys shouting "Leopard!"

or issuing the instruction to race to the end of the branches

is unclear.

But what is certain is that,

despite never having seen a leopard in their lives,

the vervets are alerting each other and have hatched an escape plan

specifically to evade this type of predator.

So what will happen if I change my mode of attack?

It's time for fake foe number two.

This time, the vervets make a completely different call...

VERVETS CHATTER

..and in response, the group stand up and scan the ground.

They clearly know they need to watch their step.

VERVETS CHATTER

That was exactly the response that I was hoping for.

The vervet in the tree gave off the alarm call which is,

"Danger, stand up, look about."

Which is exactly what the vervets did and that's because snakes

basically hunt by stealth, so if you're a vervet and you don't

want to get eaten, your best tactic is to spot the snake,

because once they've spotted it, the snakes move pretty slowly,

they don't hunt fast and so they're likely to survive an attack.

I've had two good results today. There's just one enemy left.

It was all going swimmingly until the rain started.

This rain came out of nowhere.

I don't know where the monkeys are, but if they're like me,

then they're also seeking shelter somewhere.

Rain stops play.

THUNDER RUMBLES

Eventually, there's a break in the downpour.

Given the fact that we've been waiting for the last four hours

for the rain to stop, this might be the best situation that I have

to see if I can at least get a call out of them.

I want to see how the vervets respond to an aerial attack...

and I'm hoping my hawk kite might do the trick.

Well, that's quite frustrating, actually.

What one would expect when a vervet sees a hawk, the textbook response

is to make a call and then to run into the centre of the tree.

Instead, these ones are just running into the centre of the tree

and not making any kind of calls.

Maybe I've been too subtle in my approach.

VERVET CHIRPS

I think... It was hard to tell, but I think I heard

a little couple of solitary chirp noises coming from them.

That is vervet code for, "Danger, take cover."

It means run into the centre of the trees because that's where

you're most likely to be able to avoid being attacked by the hawk.

So what's interesting is that each of those responses and the calls

have been quite different.

What science has shown is that vervets have specific calls

which relate to different predators

and seem to have a strategy for dealing with each one.

VERVET CHIRPS

"Danger, hawk! Run for cover to the centre of the tree."

VERVET CHATTERS

"Danger, snake! Stand up and scan."

VERVET JABBERS

"Danger, leopard! Head for the end of the branches."

Well, my equipment may have been a bit basic,

but I've still clearly seen that vervet alarm-calls are much more

than a one-size-fits-all kneejerk reaction to fear

like a human scream.

And they're actually a bit more like words,

symbolic signals that contain specific information.

A bit like when we shout, "fire!" or "shark!"

but with a more detailed escape plan.

Vervets were the first animals in the world whose alarms calls

were shown to mean different things.

This discovery opened the floodgates.

For years, biologists had assumed that these calls

were simple screams of terror.

Today, we know that a huge variety of animals

encode different information in their alarms.

Chickens have different warnings for aerial and ground attacks.

The ring-tailed lemur has eight different types of alarm call

and the prairie dog even describes the colour

and size of its predators.

Calls which have all evolved to try and help outwit their adversaries.

I've seen first-hand that animals have extremely complex methods

of communicating with their own kind.

But 8,000 miles away in Central America lives a creature

who's learnt to tune in to the language

of another species altogether.

This is the fringe-lipped bat.

The skies here in Panama are filled with flying spies,

eavesdropping on other animal conversations with deadly results.

Bats are extremely social animals

and are constantly in contact with the other members of their colony.

But because they communicate at ultrasonic frequencies,

normally they're completely inaudible to humans.

So I've met up with Dr Rachel Page, a leading expert in bat-chat,

who's going to help me listen in.

So this gadget here, this enables us to snoop on the bats?

How does it work, then?

So this is a bat detector.

It takes a high frequency and it'll translate it into a lower frequency.

So a frequency we can't hear cos it's in the ultrasound

and turn it into one that's audible to our own ears.

So this way we get to hear what we would never normally hear.

LOW FREQUENCY CRACKLE

'This bat has been making these noises the whole time.

'Only by converting them into a lower frequency

'are we able to hear him speak.'

It's a totally secret world that I'm just listening in to.

Animals have developed sensitivity to different frequencies

depending on their requirements.

Elephants can use low frequency rumbles

to communicate over vast distances...

ELEPHANT EMITS LOW GRUMBLE

..whereas bats communicate over a smaller area,

but need more detail, so use high frequencies.

What we can't tell from the bat detector just from listening

is how loud they are. They're actually...

In the frequency that the bat is transmitting,

they're very, very loud.

So if that equivalent loudness was at a frequency we could hear,

it would be deafening.

No, really?

So they're basically flying along, screaming their heads off.

The loudest species of bats recorded

have been up to 140 decibels, which is extremely loud.

As in humans, sounds are detected by the bat's ear as vibrations

and transmitted by the nervous system straight to the brain.

Almost all animals receive sound in the same frequency range

that they broadcast on.

Because they transmit at a higher end of the sound spectrum,

it was assumed that bats couldn't detect noises made at a lower range.

But it seems that the fringe-lipped bat has learned to eavesdrop.

Scientists noticed that they seemed to be able to find

and identify frogs with huge accuracy,

even in the dense, dark surroundings of the rainforest they live in.

The only explanation is that the bats have developed sensitivity

to a second frequency band.

They may be pre-set to Radio Bat but they're tuning in to Frog FM.

So do all bats eavesdrop on frogs or is it just this particular one?

-This is the only bat in the world that does this.

-Really? Wow.

So it seems like it's specially adapted to eavesdrop on frog calls.

To show this eavesdropping in action,

Rachel has devised an experiment.

Obviously, we don't want to put a real frog in harm's way,

so we're going to use Robofrog, a made-to-measure model.

ROBOFROG CHIRPS

Above him is the bat.

If this bat really is a spy and can speak frog,

we're about to find out because as soon as I press the call button,

he should wake up and fly down and get the frog. Here we go.

ROBOFROG CHIRPS

We're doing the experiment in the dark as that's when bats hunt.

ROBOFROG CHIRPS

Oh! Look, his ears are going, his ears are going!

They're really turning, aren't they?

Yay, he did it, he did it.

-He did.

-That is amazing.

What makes it even more impressive is that the bat isn't just locating

the frog from its call, it's also deducing the size and toxicity.

There are almost 200 types of poisonous amphibian

in South and Central America.

The fringe-lipped bat has learned to recognise the calls of toxic species

so that their frog supper doesn't prove fatal.

So eavesdropping is an incredibly useful survival skill and these bats

are sonic spies that have learned to crack the frog code to stay alive.

I've met an animal which listens in on the language of its prey.

But now scientists have discovered that there's a creature

who's actually learned to talk back.

I've travelled 3,000 miles to the Californian hills.

This place may look peaceful

but it's home to one of the most dangerous reptiles

in North America...

the rattlesnake.

These ambush predators are cleverly camouflaged

and stealthy in their approach, so I need to take precautions.

I'm not taking any chances.

I've never met a rattlesnake before,

but I'm guessing they're not very friendly.

This is one of our research animals,

one of our captive rattlesnakes that we use to simulate an interaction.

Dr Rulon Clark has been studying the snake and its enemies

for the last 12 years.

SNAKE'S TAIL RATTLES

You see, he's a little bit alarmed but still fairly docile, actually.

You can see he's in this tube and his head, the dangerous part

of his body, is all the way up here and is restrained by the plastic.

-He's perfectly safe.

-Can I touch it?

-Sure.

It's really cold. He's got to be...

-I don't know, feels like 10, 15 degrees cooler than me?

-Yes.

'This cold-blooded killer could easily take down a human,

'but the rattlesnake has his eye on a different prize...

'the ground squirrel,

'a small rodent which is common in North American scrublands.'

So how much of this snake's diet would be made up of ground squirrel?

Almost 70%, 80%. Some of the snakes around here, we've never seen them

eat anything or hunt for anything other than ground squirrels.

So to help locate their favourite food,

the snake has evolved an extraordinary ability.

You can actually see in-between his nostril, the end of his nose there,

and his eye, there's that little pit in his face.

That pit has a heat sensing membrane in it. They can see heat with that.

In exactly the same way their eyes detect light,

these pits detect heat as particles of infrared radiation.

Combining these visual and thermal images allows the snake to track

its prey with pinpoint accuracy.

And that makes it all the easier to catch squirrels?

Yes, they have an extrasensory perception of warm-blooded animals.

They'll see them at dark, they'll see them at night.

They'll see them more vividly when there's grass obstructing them.

Things like that.

-So it's like a super-sense?

-Yes.

So we're about to do an experiment to see exactly what happens

in a stand-off between a rattlesnake and a ground squirrel.

On one side, we have a top predator that hunts by stealth,

can see in the dark and has a powerful venomous bite.

And on the opposing side is an animal

who could best be described as...

fluffy.

But the ground squirrel has found a way to fight back.

In order to get a snake's-eye view of the encounter, we're going to

use this specialised camera that can actually see heat.

Here comes the squirrel. You got the thermal?

So this dark blue cold-blooded blob here,

that's the snake?

And this orange figure darting around, that's the squirrel?

Yes, exactly, you can see how warm the squirrel is.

See how warm his body is? It's kind of brighter orange.

You can see he's coming in and he's waving his tail.

Look how warm his tail is getting when he does some of this waving.

It's almost as warm as his body and occasionally he has these

flashes of heat in it that are even warmer than his body.

Yes, you can, you can see it suddenly flashes up orange

inside the tail.

So this is a specialised form of communication.

It's just to talk to a rattlesnake.

So they have a specialised way of sending a message to a rattlesnake

using heat or infrared light which is only something

that a rattlesnake can see.

By pumping warm blood into its tail,

the squirrel is sending a message directly to the rattlesnake.

"I know you're here. The ambush has failed."

Is this the first time anyone has ever seen an animal

use infrared in this way?

Yes, this is the first example we know of

of infrared communication in animals.

How do you know that he doesn't just do this all the time anyway?

If you watch how these squirrels interact with a gopher snake,

which is a different snake predator, their tail temperature is different.

They don't heat it up and gopher snakes can't see infrared light.

The fact that the squirrel only does this when the recipient

of their communication can actually see it indicates that it's

specially evolved to send a message to this particular type of animal.

That's such a finely-tuned piece of evolution, isn't it?

Yes, it's amazing, isn't it?

It's just one aspect in this whole co-evolutionary process

between these two animals.

This squirrel has developed an extraordinary survival skill,

a language created specifically to speak to its enemy.

Squirrels and rattlesnakes have been locked in an epic evolutionary

battle for about 10 million years

and this creation of a novel infrared communication system

is just the latest in a long line of attack and counterattack moves.

And it can't help but make me wonder

what kind of crazy super-power might evolve next.

When staying alive is at stake,

animals have developed extremely complex forms of communication.

But what I want to look at next is whether they're as sophisticated

when it comes to talking to those closest to them.

Having friends is often thought of as a uniquely human trait.

But recent findings have started to suggest that it's an important part

of animals' lives, too.

To find out more, I've come back to the UK

to visit a Sussex University research site.

Professor Karen McComb studies the social lives of horses.

What is a horse's social circle like?

Their core social group is a group of females who aren't relatives.

That's the interesting thing, they're not related,

and they hang out with their stallion.

They have particular individuals that they spend more time with,

so sort of the equivalent of human friends.

They like spending time with certain individuals over others.

Whether you're human or horse,

it's been shown that having friends can bring huge health benefits.

But do they think of them in the same way that we do?

As humans, we take it for granted that when we hear the voice

of someone we know, say, on the end of the phone, we conjure up an image

of that person in our mind.

Now, this ability was long thought to be unique to mankind.

So the big question is, can animals do the same thing?

Karen believes that horses can conjure up

mental images of other horses,

even when they're not around.

So this here is Pepsi.

This is Lance, here, and on the end that's Fi

and these horses are all pretty good mates.

They've been sharing stables and grazing together

for about six and a half years.

So they're all very aware of each other's voices and their faces.

In order to show that horses can conjure a mental picture

of their friends, we're going to do an experiment.

Fi has been taken back to her stable,

leaving Lance and Pepsi alone in the field.

So first up, if Lance ever stops eating,

is we're going to show him Pepsi, his stable-mate,

and then we're going to take Pepsi behind the horsebox

and play Pepsi's whinny.

Stop Pepsi there, perfect.

Come on, Lance, you need to take a good look, drink in Pepsi.

Yes, he's clocked that Pepsi's there, for sure.

Say goodbye to Pepsi, Lance.

-Off she goes.

-Jane's taking Pepsi in behind the horsebox,

the horsebox simply acting as a barrier here,

so Pepsi is now going to disappear from sight.

Pepsi is gone.

I'm just going to play Pepsi's whinny.

RECORDING OF PEPSI'S WHINNY

So he's a bit interested but not overly bothered.

That's what he was expecting.

He saw Pepsi and he just heard Pepsi's whinny there,

so he's gone back to grazing.

We'll see what happens when Pepsi's whinny sounds again.

RECORDING OF PEPSI'S WHINNY

-He's just not bothered.

-He's not bothered.

What he saw matched what he heard

and he's just getting on with what he was doing before.

As far as Lance is concerned,

Pepsi is the only other horse nearby,

so how will he react when we play Fi's call instead?

This time it's not going to be Pepsi's whinny,

it's going to be a whinny from Fi.

RECORDING OF FI'S WHINNY

Now, he looked very quickly there. Keep a loose rein on him.

So he's still looking...

..and he's still listening.

Do you see the way his ears are pricked and very attentive?

He's still paying attention to that.

He definitely gave a reaction.

'Lance's response may not have been massive but the implications are.

'For him to react in surprise suggests that he has advanced cognitive abilities.'

When he saw Pepsi, he was expecting to hear Pepsi's whinny

because his mental picture of Pepsi is quite complex.

It's got what Pepsi looks like, also what Pepsi sounds like,

maybe what Pepsi smells like

and the voice he heard didn't match the mental picture.

'The idea that animals think in the same way we do

'is truly ground-breaking,

'fundamentally rewriting our understanding

'of how their minds work.'

It gives us the first indication that animals really do have pictures

of others in their minds that's complex in the way that ours is.

Karen's research suggests that horses can maintain mental images

of at least 30 friends...

and they aren't the only animals who have wide social circles.

Sheep can recognise the faces of 50 of their flock,

and remember them for over two years.

Elephants can recognise up to 100 voices.

That's the same number of friends the average person has on Facebook.

I want to find out more about the communication that's evolved

to support these animal friendships.

So I've come to Scotland to meet one of the most social

and talkative animals on the planet...

the bottlenose dolphin.

We know that, like us, relationships are really important to dolphins

yet they live in this vast, featureless landscape so,

if you're a dolphin, how do you keep up with your friends?

My guide today is Dr Vincent Janik,

one of the world's leading experts in dolphin communication.

-So how easy are they to find, these dolphins?

-That's a good question.

-It's different every day.

-Right.

So, normally they're kind of in this area here,

so this is the mouth of the Tay.

This is the area we see them the most.

'Luckily for me, it isn't long before a school appears.'

I just saw a big splash over there, like a really big splash.

Wahoo!

What is it about seeing dolphins that just makes you so happy?

Wonderful.

As it is for us, dolphin communication is wide-ranging.

We know that they use touch and body language,

but in the limited visibility of the sea,

it's sound that is the most important.

'But to decode some dolphin chatter,

'we need to record a group interacting

'and Vincent has an underwater microphone to help me listen in.'

This is the hydrophone that's going to enable us to hear

what the dolphins are saying.

So hydrophones are in the water which means that if I turn this on,

it will reveal the underwater world.

HIGH-PITCHED WHISTLING

You can hear the whistles!

Suddenly the mysteries of the deep revealed.

These whistles may be unintelligible to us, but by analysing them closely

over the last 20 years, Vincent has deduced something extraordinary...

We have two different whistles here that you can hear.

..that dolphins have names.

So this is two animals exchanging who they are

before they're getting together.

This is amazing, so this is a dolphin greeting.

HIGH-PITCHED WHISTLING

Vincent's research has given us an incredible insight

into dolphin communication.

By playing signature whistles and carefully monitoring which

dolphin responded, they deduced that each individual has its own name.

Those are very special because these guys

actually developed them themselves.

So every animal invents its own whistle after it's born

-in the first few months of its life.

-Fabulous.

That's such a fantastic thing that they choose their own names.

-"This is me for my life."

-Yeah.

-That's wonderful.

But what's even more remarkable is that they can copy

and broadcast the names of others in order to make contact...

HIGH-PITCHED WHISTLING

..just like we do.

It's the first time this trait has been shown conclusively

in any animal other than humans.

So why do you think

it's so important that dolphins have evolved names?

One of the interesting aspects about their life is that

their social lives are kind of similar to humans as well.

We live in something that's called a fission-fusion society

and what that means is that people like to be together.

They're not always together, they sometimes go apart

and then come back again so it's fission and then fusion again.

Because they lead this life, they need to have a great way

-of recognising each other just by listening.

-Yes.

It's a very effective system to stay in touch.

And the dolphins aren't the only ones chatting constantly

below the surface.

Sound travels four times faster in water than it does in air,

so for many marine animals, the sea gives them a super-fast connection

to their friends worldwide.

FISH THUMPS

Some fish make drumming noises to attract a mate...

WHALE SINGS

..and whales have conversations that can span entire oceans...

..with individual calls known to reach from the Caribbean to Canada.

Dolphin social lives are a lot like ours.

They are dynamic and ever-changing.

We might start the day with family, then go to work,

then finish the day with friends.

Dolphins are doing more or less the same thing, but they're doing it

without any regular hang-outs like home or the office.

But by evolving individual names,

they manage to find and maintain relationships even in the dark.

HIGH-PITCHED WHISTLING

I've seen for myself that animals are constantly thinking about

and talking to their nearest and dearest.

But for the final leg of my journey,

I want to see how animals communicate with the different

species they share their habitats with.

So how do animals speak to their neighbours?

I've come here to the Kalahari Desert in South Africa

to investigate a surprising relationship

between two very different species with communication at its core.

The Kalahari covers almost a million square kilometres

and is home to huge variety of animals...

both great and small.

These are the meerkats and...

Looking very intently from side to side.

They're incredibly anxious animals, always looking around for predators

or rival gangs and they spend their lives foraging

with their heads in the sand.

And that way they're more vulnerable so they really need a neighbour

to watch out for them.

Enter the fork-tailed drongo.

This bird may look unremarkable

but Dr Tom Flower believes they're anything but ordinary.

Drongos provide a sentry service

and by that I mean that they are the eyes on the skies, as it were.

When meerkats have got their heads down digging,

the drongo is looking out and often is the first to spot predators.

So the drongo then makes an alarm call

and the meerkats eavesdrop on that and all dash to cover.

So the drongo is quite a handy neighbour for the meerkat to have.

It definitely is.

So tell me about the experiment we're going to do today, Tom.

Now we could hang around and wait for a hawk or an eagle to fly by,

hope that the drongo spots it first and makes an alarm call.

However, we'd probably be here for a very long time.

So to encourage the drongo to issue a warning...

Let's go and set up the experiment.

..Tom's choreographed his own aerial attack.

Here we are, stuffed by my own fair hand.

This is a little juvenile male who'd been hit by a car

and, sadly, passed away.

He's now being put to good use as a zombie falcon.

That's incredible, I'm so impressed that you've got an actual falcon.

I thought you'd have a model.

'To bring this bird back to life,

'we're going to attach it to a zip-wire.'

-Yes, that's good.

-We just need to do a last check.

-The meerkats are over there.

-Tick.

-The falcon is up there.

-The drongo is just there.

-Yeah.

-So let's see what happens.

Hopefully, he'll alarm at that and then the meerkats will dash to cover.

-OK.

-Ready?

One, two, three...

There he goes!

DRONGO CRIES OUT

-That was success.

-It absolutely was.

They've all dashed to a bolthole

and they're all sitting there looking around now.

That's because they've heard the drongo call.

-So the sound that I heard...

-That's one of the drongo's alarms

that they make at predators.

That call is only ever made when they see a predator.

So we've just seen the drongos

behaving a bit like a meerkat neighbourhood watch scheme.

But it's not that simple...

cos the drongo has a dark side.

Tom has noticed that they sometimes make an alarm call

even when there's no threat.

DRONGO CRIES OUT

The meerkats scatter in panic...

leaving the drongo to swoop in and snatch what's left of their lunch.

It's the first time a bird has been conclusively shown to be using

alarm calls specifically to deceive another species.

So if the meerkat is being deceived by the drongo on a regular basis,

how does he not wise up?

Well, they do. That's the problem for the drongo is that its own alarm

stops working very quickly, just like the story, The Boy Who Cried Wolf.

However, the drongo's got a trick up its sleeve,

because it can mimic the alarms of other species.

By using the warning call of others,

which the meerkats also associate with danger,

the drongo is back in business.

So when one call stops working, it switches to the next type of call

and, sure enough, the meerkats are deceived again.

So whilst many of the animals here in the Kalahari

understand other languages,

the drongo is the only one that can speak other languages.

That's right and that's the key to their deceptive success.

The drongo is the ultimate identity thief.

They have 30 different calls,

15 of which have been stolen from other species,

from the lilac-breasted roller to the pied babbler.

While other animals, such as pigs and chimps, have been known

to deliberately deceive others,

the drongo is the only animal we know of

which can change its tactics to keep up the con.

In order to see this crafty bird swap disguises,

Tom's come up with a test subject who can be easily manipulated.

Meet the Womble.

No, no, no, no! Sorry, I'm chasing the sound man. Come back...

-LUCY GASPS

-Shoot!

It did actually take seven goes for me to pass my driving test.

I didn't tell you that.

-I've got it. It's coming back.

-Watch out for the mini camera.

I've brought the whole thing back in reverse. OK.

There you go, which is good.

-Check that out.

-Beautiful.

So, Tom's Womble is a slightly eccentric creation

but it's going to show us how the drongo hones his deception skills.

First of all, I'm going to load up the worms. I'll do this bit for you.

The Womble is carrying some tasty treats.

But will the drongo try to trick it, just as it does with the meerkats?

There we are, stop there.

I'm now going to drop the worms.

Are you interested, Mr Drongo?

You need to alarm to get those worms.

DRONGO CRIES OUT Now run, go, go go.

-That call was a mimic of a lilac-breasted roller.

-Oh, really?

Absolutely. That "crrr" kind of call.

But what happens if that one stops working?

OK.

Having worked last time,

the drongo tries his luck again with the same call...

DRONGO CRIES OUT

..but the Womble refuses to budge.

as far as the drongo is concerned,

this alarm call is no longer trusted...

so he switches strategies and imitates another bird,

-the Marico flycatcher.

-DRONGO WHISTLES

So that's fascinating.

He totally changed his tactic when it didn't work.

When he got no response from the Womble, he changed what

he was doing in order to get the response that he wanted.

Exactly and that's how he can keep his racket going.

Just like the boy who cried wolf, his alarm does stop working,

but then he mimics something else.

That's the genius behind this bird, isn't it?

That's how he manages to do something that no other animal

is known to do and be able to keep deceiving the same animal simply

because he's got this repertoire of calls that he uses so tactically.

That's correct.

So far, the only place where the drongos have been shown to do this

is here in the Kalahari.

With food scarce in this desert landscape,

the drongo has adapted to give itself the best chance of survival.

3..2..1..

Tom's findings so far are fascinating,

but his work is far from over.

It will be a truly ground-breaking discovery to show that animals,

like humans, use communication to intentionally manipulate

the minds of others, and one that strikes at the very core

of what separates humans from other animals.

Tom's got a lifetime's Wombling out here in the desert in order

to crack it but I've no doubt that if anyone can do it,

I think Tom can.

My adventure into the world of animal communication

is almost at an end.

But back in Kenya, there's one last set of neighbours I want to meet

and they're the most remarkable pairing of all.

I set out on this journey to learn how to talk to animals

and I've met some brilliant scientists

who've shown me how they do it.

But in the grand scheme of things, science has only just started

to have these conversations.

Here in the Masai Mara, humans have been talking to one particular

animal for thousands of years.

This is the greater honeyguide,

a bird which has learned to speak to humans.

-Hello, Moses?

-Moses, yeah.

-Moses, hello, nice to meet you. Hi, there.

-Nice to meet you.

-Hello, what's your name?

-Musanga.

-Musanga? Lovely to meet you.

-Mancha.

-Mancha? OK, good to meet you all.

-So you're going to teach me about the honeyguide?

-Yes.

How do you get the honeyguide to come to you?

We whistle for the bird like...

-HE WHISTLES TWICE

-Hiih.

-SHE WHISTLES TWICE

-Very good.

And then what did you do? You went "ahh" afterwards?

-Hiih.

-Hiih. Hiih.

-SHE WHISTLES

-Hiih.

All right then, let's go and get ourselves some honey.

Yes, let's try our best today.

For the Masai, locating a beehive in the vast plains could take weeks.

But with the honeyguide's help,

the time spent searching can be drastically reduced.

THEY ALL WHISTLE

Hiih!

-Hiih!

-Listen for a minute.

What sound am I listening for?

Chh-chh-chh-chh.

That's the sound of the honeyguide.

-You hear nothing?

-Absolutely nothing.

Just the sound of the wind in the trees.

BIRD SINGS

-That's a different bird.

-Oh.

My whistle's going to run out if we have to do this much longer.

Come to us, honeyguide.

-What's that bird?

-That's not it.

That's not it. OK.

(Not it.)

After hours of searching, our persistence finally pays off.

THE BIRD CHITTERS

-Where is it? Where is it?

-Over there.

-It's on this tree.

-Oh!

-There we go.

THE BIRD CHITTERS

We've found the bird.

'This is a call that they only use to communicate with humans.'

'He's telling us to follow his lead.'

'The honeyguide has exceptional eyesight

'and can scour far greater distances than the Masai could cover.'

THE BIRD CHITTERS

'We follow the distinctive call through the scrubland...

'and finally, we arrive at a hive.'

Oh, my goodness, there's bees in there.

But why would a bird go out of its way to help humans?

'The answer lies with the aggressive African bee.'

The honeyguide wants the beeswax and grubs from within the nest,

but its stings could be fatal to a bird this small.

'So they've entered into a mutually beneficial relationship

'with the Masai, who can harvest the honeycomb for them.'

These African bees definitely are very, very, very dangerous bees.

They're very aggressive.

He's outrageously brave,

sticking his hand in the hive like that.

I'm holding this to protect myself from getting stung by the hundreds

of angry bees that have now exited that tree.

Oh, my goodness me, there are thousands of bees!

The honeyguide has fulfilled his side of the bargain.

We're going to lay some honeycomb out for it,

which is apparently part of the etiquette.

'Now it's our turn.'

With the honeyguide happy,

we can finally enjoy the fruits of out labour.

This had better be good.

Sweet?

Mmmm!

-Delicious.

-That is the sweetest honey I've ever had.

There are very few examples of animals

working co-operatively with humans.

Some dolphins have been spotted helping fishermen in Brazil,

but the honeyguide's ability to talk to us

in order to achieve a shared goal is almost unique.

I've been all around the world, meeting top communication scientists

in order to talk to animals, but it's here in the Masai Mara

that I've been part of the most profound conversation,

one that's been going on for thousands of years

and is truly beneficial for both man and bird.

And to have been involved in that dialogue

has been really, really humbling.

My journey is almost over but I've discovered that animal communication

is so much more sophisticated than I could ever have imagined.

Animals are sending complicated messages, not just to their own kind

but to entirely different species and even to us.

It's touching to discover that animals strive to stay connected

to a wide social circle of family and friends.

But what's most impressive are the extraordinary systems they've

evolved to broadcast information and stay in touch.

I started this journey with a question.

Can we really talk to the animals?

And now I know the answer is yes.

We have started that conversation.

And if science keeps advancing the way that is,

then the potential for that dialogue is truly astonishing.