Episode 1 Talk to the Animals

From the loudest roar...

ROARING

..to the smallest squeak...

SQUEAKING

..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 Doolittle 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 secret seismic chatter...'

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 like a welcoming party.

'Whether they live in families, herds or packs,

'communication is at its richest in animals that live in groups,

'and I want to find out about the sophisticated methods they use

'to get their messages across.'

So I've come here to East Africa

to meet three very different animal clans with three

very different ways of keeping in touch. I'm going to eavesdrop

and even join in.

'My first stop is the Queen Elizabeth National Park

'in Uganda - home to one of the most social creatures on the planet.

'Not the mighty lion, nor the graceful giraffe.

'My epic journey begins...

'..with the banded mongoose.'

Oh, look at them.

Aw. Hello.

These are the banded mongoose.

As you can see, they're very curious.

Look at this.

Hello. Hello!

And that's because these ones are habituated to scientists,

so they're used to having humans around.

This is one extended family,

and as you can hear they're really chatty characters.

There's a lot of gossiping going on.

This one's getting a bath.

'The banded mongoose is native to Africa,

'and, like their more famous cousins the meerkats, live cooperatively

'in clans of up to 40.

'But, uniquely, mongoose females within the group even give

'birth on the same day and their young are raised collectively.

'Dr Emma Vitikainen is part of a team who study

'how these animals live, and communicate.'

So, Emma, what I've noticed about them,

which I love, is they're so noisy.

They just seem to be chatting the whole time.

They really are.

They constantly make little noises. They've got a very complex

social life and need to coordinate carefully in order to be successful.

So, if you're just a lone animal,

you don't need to have great communication skills.

But if you do have a very complex society then you need to have

-complex language abilities, is that right?

-Absolutely.

They've got lots to talk about

because they do everything as a group.

Starting from foraging, they find food together.

And then there's all the duties for childcare -

who does the baby-sitting, who's your escort, who do you need to stick by?

All these very complex behaviours,

and communication really is key in co-ordinating all that

within the group.

'So, to keep their structured society running smoothly,

'the mongooses have become very vocal indeed.'

They really are insanely chatty.

CHIRPING

To begin with, it's a cacophony of squeaking, but now I've been

here, I can actually hear there are different squeaks going on.

'By studying the sounds mongooses make in different

'situations, the scientists here have decoded

'several different noises, or calls.'

'But there's one call that's absolutely vital

'to the wellbeing of the clan - the contact call.

'A signal broadcast by each individual to maintain

'constant contact with the group.

'To try and capture some of these calls, Emma's sent me

'out with a microphone.'

This is going to be difficult, I can tell.

Oh, don't run off!

It's a wonder science has managed to find out anything

about mongoose calls.

'Eventually, I manage to pick up a few squeaks

'and take them back to Emma.'

-So, Emma, how did I do?

-Well, you actually did pretty well, I thought.

There's lots of sound files and lots of background noise.

There's lots of you walking around, but I managed to pick a piece

where there is really quite a good contact call.

MONGOOSE CONTACT CALL

I did it, I got you a clean call, that's fantastic.

So, now what does it mean?

In order to see that, I've created a spectrogram,

and this is the end result.

0.5 seconds long. See, there's two bits in the call.

This is what we call the noisy part of the call,

and the harmonic part of the call.

So, that one tiny squeak that I recorded

contains two separate calls, basically.

Yes. The first part, that tells other mongooses who is calling.

The second part is basically shouting out what it's doing.

That's wonderful. I just love it.

So much information is contained within a call

that's just half a second long.

So, how many different types of contact call have been established?

There's three different types.

So, the first one and the most simple one

is when a mongoose is digging.

MONGOOSE CALLS

Then when they're foraging, finding food, with their nose

on the ground, it's searching.

MONGOOSE CALLS

And when they're just on the move,

nose up, moving from one patch to another,

that's the third type of call.

MONGOOSE CALLS

This simple-sounding call is packed full of information.

Every single mongoose has its own unique signature and, when placed

in front of what it's doing, is used to update others on its status.

So far, contact calls have been confirmed

for three of the most common mongoose activities.

If you think about it,

if you're a mongoose, you've got to stay in a pack.

A lot of the time, they're foraging for bugs and beetles

and they've got their head in the ground, so this noise is the

best way for them to keep in touch, to keep in contact with each other.

This is social networking, mongoose style.

But these sophisticated squeaks aren't the only method

the mongooses use to keep in touch.

'They're communicating constantly in another language altogether.

'To find out more, we need to gather the group,

'and there's one sure-fire way to get their attention.'

Who fancies a little bit of water? OK?

SQUEAKING

'At first, the pack react vocally.'

Wow! That is the sound of a mongoose party!

But then the group begin using an entirely different method

of communication - scent.

That's amazing.

So, after the water call, there is a frenzy of scent marking with

even the little pups getting involved in it.

-Yeah.

-So them rubbing their bottoms on the branch is them

leaving their scent, basically.

Yes, everyone has to join in and it's really like building a team spirit.

Everyone has to smell the same.

So, it seems like scent is really important to mongooses.

It's an essential part of everything they do.

Whether it's marking out territory, establishing hierarchy, or

keeping in touch, scent is essential in all aspects of mongoose life.

In fact, scent, or chemical communication, is used by almost

every animal on the planet, from the primitive, to the most complex.

Some insects leave pheromone trails to be followed by their fellows.

Certain moths can sniff out a potential mate

from up to seven miles away.

Even underwater, fish use smell to stay in formation

with their friends.

These invisible messages are all around us.

Well, this has been a great place to start.

The mongoose family is the most organised I've ever met,

and what's fascinating is how much they have to communicate

in order to keep that well-oiled machine ticking over.

But the real eye-opener

is how animal speak is far more than just cries and calls.

They're communicating constantly

in ways that we can neither see, nor hear.

'I want to find out more about these hidden worlds,

'so I'm travelling 300 miles to Murchison Falls on the Nile.

'In the animal kingdom, social groups come in all shapes and sizes,

'so I'm switching from one of Africa's smallest mammals

'to one of its largest...

'..the hippopotamus.'

Almost a third of Uganda is made up of bodies of fresh water,

making it the perfect place to study hippos.

'This 25-mile stretch of river alone

'is packed with an estimated 15,000 of them.'

I love hippos, they're such massive oddballs.

Your average hippo weighs about the same as a family car.

They have enormous powerful jaws and long, sharp incisors

and are famously aggressive and, in fact, they are supposedly

responsible for more human deaths than any other African animal.

But for a bunch of grumpy misfits, they're incredibly talkative.

So I'm hoping to be able to join in, and have a chat with them myself.

'To help me get the conversation started, I've met up with Professor

'Bill Barklow, the world's leading expert in hippo communication.'

I can count 27 hippos right there.

'He's been listening in on them for almost 30 years.'

Every one of them capable of making a 120 decibel sound.

That's as loud as being at a rock concert

-and standing next to the speaker.

-It is.

Yes, and all at the same time. It's quite an experience.

Hippos live in large groups or pods, which

can contain up to 100 individuals, all clamouring to keep in touch.

So, what's the repertoire like of a hippo?

Up to 25 or 30 different sounds that they routinely make.

All kinds of screams and growls and grunts and whines.

Pre-linguistic mammal sounds.

Sounds that we all know about.

-Growl means what to you?

-Growl means you're angry.

Yeah, and if I go... HE WHINES

-Then you're being submissive.

-Submissive or frightened.

And if I go... HE SHRIEKS

What would you say that is?

-Ha-ha! You're trying to frighten me!

-I know. So you were frightened.

They do make some sounds that are apparently only made under water.

One of them is a whine, a very high-pitched "wooooo!"

And clicks, not just one click but...

HE CLICKS RAPIDLY

Like that, and there's a huge range of variations of these things

that they can make under water, it's just hilarious to listen to.

'Bill's going to help me eavesdrop

'on some of these hidden hippo sounds using a hydrophone,

'an underwater microphone connected to a speaker on the boat.'

It's like we're going fishing for hippo sounds.

Keep going.

CROAKING There, did you hear that?

That was a croak.

That croak sounded like a frog.

It's just like a frog, so I named it a croak and they're a very common

sound, probably the most common underwater sound that hippos make.

They're made mostly by the little ones, calves which will play

with one another underwater, often with one female protecting them.

It's a creching behaviour where one female will take care of other

females' babies for an afternoon.

The water is the colour of coffee with cream in it,

so you can't see anything more than a foot away.

So she only has her ears to keep track of the little ones.

So, that croak is basically a hippo baby monitoring system.

That's precisely what it is, yes.

That's fantastic - and what I love is that it's showing a more caring

-side to the hippo.

-Yes, they care for their babies.

'Bill's findings have given us a remarkable insight

'into how hippos keep in touch underwater.

'But his work has also uncovered something completely

'unique in the animal kingdom...

'..that hippos can communicate above and below water simultaneously.'

I first saw hippos on a safari to Africa.

Late in the afternoon they started to interact,

the hippos did, and they started to call,

and then I noticed that maybe five other hippos surfaced,

came up to the surface, as if they'd heard an airborne sound underwater.

And that, I thought, was breaking the laws of physics.

We scientists live for the idea of something new,

something that no-one else has ever heard before,

and I thought, "I've got to check this out".

'Bill calls this phenomenon amphibious communication...

'..and he's devised an experiment to show me how it works.

'We're going to play the call of a hippo from a different pod.

'Hearing it should provoke the local residents into a chorus,

'each stating that this territory belongs to them.'

So, right now, it's a lovely, quiet evening here on the Nile.

But I'm hoping to completely change all that by playing this call,

which should start a contagious calling session

of all the hippos in this area.

So, let's see if it works...

I'm about to say hello to the hippos.

'Will the hippos hiding underwater get the message?'

HIPPO CALLS ON TAPE

GRUNTING

'The dominant male takes the bait.'

That was another one over there, wasn't it?

There's heads popping up everywhere.

'His call has set off a chain reaction.'

That's fantastic how it spreads, isn't it?

It's phenomenal. And you heard them out here, didn't you?

-Yeah.

-It's contagious.

'Amphibious communication allows hippos on the surface to

'contact their podmates, both above and below water,

'at the same time. But how does it actually work?'

So, the sound above water comes out of the nostrils.

How does the sound get transmitted below water?

The underwater sound is produced by a great roll of fat on their throat.

So, when they make a sound with their larynx, vibrating the vocal

cords, it passes through that fat without resistance into the water.

So, it's a direct transmission from the throat into the water.

'The noise travels from the voice box,

'through the fat, straight into the water.

'But making sound below the surface is only half the story.

'Bill wondered whether, as with some marine mammals, their jawbone

'was acting as a receiver for sound,

'sending it straight to the inner ear.

'Years later, he was proved right.

'Genetic analysis has since shown that the hippo, a land mammal,

'is in fact most closely related...

'..to whales...

'..and dolphins.'

It's been a total revelation to discover that hippos

can communicate above water and below water simultaneously,

and they're the only animal that can do that.

But what's really fascinating is that they're communicating using

a technique that's used by their cousins the whales

and dolphins far out at sea.

And that is really remarkable.

GRUNTING

They just don't stop. It just doesn't stop.

'Both hippos and mongooses have fascinating social lives,

'but now I want to see how communication works in an animal

'more similar to ourselves -

'our closest genetic relative.

'The chimpanzee.'

Scientists have spent decades working with chimps,

trying to teach them to talk to us.

Some even learned sign language.

But in order to truly understand their communication,

we have to stop speaking human and start learning chimp.

So I've come here, to Budongo National Forest in Uganda,

one of the largest natural forests in east Africa

where you can still see wild chimps.

And I've been given permission to visit

one of the world's greatest chimp communication centres.

I can hardly wait.

The team here is pioneering a completely new approach

in the study of chimp communication,

and Dr Cat Hobaiter is at the forefront of the work.

We basically try to be non-existent.

We try to be trees in the forest and we're not interacting with them,

and they're very used to us, so we can follow them

around the place without really disturbing their natural behaviour

and just we sit quietly somewhere, don't interact with them and

just let them get on with their lives and their communication.

Right, so, it's really different to how things have been done before,

-isn't it?

-We don't want to change their behaviour

and we don't want to know what they have to say to us,

we want to know what they have to say to each other.

'To see this approach in action,

'I'll have to trek deep into the forest.

'But with night about to fall,

'my field trip will have to wait till morning.'

It's six o'clock in the morning and the sun is just coming up,

and we're going off to try and find the chimpanzees.

To say I'm excited is a complete understatement.

It's not every day that you get to fulfil

one of your lifetime ambitions, and today is one of those days.

CHIMPS CALL OUT

My God! The sounds they make - it's extraordinary!

It's like a welcoming party.

'In fact, chimps have around 30 different calls, and, like humans,

'they often reinforce their messages by combining them with gestures.

'So, to truly understand what the chimps are saying,

'we have to learn another language altogether -

'body language.'

-Is it a very intimate scene that we're watching?

-It is.

What's really lovely about these guys is that you've got a mum

and all four of her children together.

What they're doing is grooming each other.

So what I'm looking for at the moment is all of the little gestures

they use to each other.

And they're grooming different parts of each other's bodies, so maybe,

"I want to groom your arm over there so I'll give you a little nudge."

They'll offer the arm and they'll groom here.

'Through movement alone,

'this family are issuing each other with a clear list of instructions.'

These grooming gestures are a lot more subtle than I'd have expected.

I'd never have guessed that that was communication.

It's a little bit like if your mum's brushing your hair, she'll

move your head to that side and you'll have to hold it in position.

It's not just about picking you up and putting you over here,

it's about asking you to move over there.

A really close-knit family like this,

they really don't need to say that much to each other.

That's right.

With your family, a look might convey an entire sentence

because you know each other that well, so that's the equivalent

-going on there.

-Absolutely.

It is an incredible privilege to be able to sit in their world

really close to them and for them to just carry on conversing

with each other. It means that you're really seeing

their true behaviour and really listening to and witnessing

incredibly intimate conversations and communication between them.

'But in order to see some different gestures,

'we need to find another group.'

That's a new born baby up there.

CHIMPS WHOOP AND CALL EXCITEDLY

Today is the first day that she's

come into the community with the baby.

It's incredibly exciting, not just for us, but for all the chimps.

I love the fact that they're like some big Italian family,

all really fired up because there's a new baby around.

And all these different groups are coming to visit the baby

and check it out.

But for that reason, we have to be very careful today,

because there's a lot of emotion running high with the chimpanzees.

'As we watch on, two males begin to make dramatic displays.

GRUNTING AND SCREAMING

(My heart is going like the clappers!)

A chimp came barrelling through here.

What happens to the males is when they get really excited -

a bit like our goose bumps - all of their hair stands on end to

make them look twice as big, and as he went through there

he barrelled straight into the female with the brand-new baby.

And of course she then panicked completely, as you would.

Did you notice any gestures?

Well, it's really hard to see in this dense undergrowth,

but in that situation, I'm almost certain a really common gesture and

something that's very familiar to us is that she would reach her hand out

and that'll be it, they'll have made up

and that's when everything calms back down again.

It's lovely to see those little gestures that are so intuitive.

'Things move so fast in the field,

'it can be easy to miss the true significance of these gestures.

'So, back at camp, Cat shows me footage

'of a similar interaction between a new mother and an aggressive male.'

What we've got here - he's basically threatening her,

he's challenged her a little bit,

so she decides to go and really communicate to him,

just to make sure that he, hopefully, just leaves her alone.

-And you see that she basically...

-Oh, she stuck her hand out.

..gives a beautiful little reach just over to him while looking at him

and then she just keeps looking at him to make sure as she moves away.

That worked really nicely for her, because he then sits down,

she goes away, game over - and then she can get on with her day

without getting beaten up or anything nasty happening to her.

'Having analysed hundreds of hours of footage,

'Cat knows that even the most innocent of gestures

'can conceal an ulterior motive.'

What we've got here

is one of the big, dominant males and another female, and he actually wants

to groom her, because he would really like for her to come away with him.

What he does is give some beautiful, big, loud scratches,

and they're really obvious gestures, but she doesn't do anything

at that point, so what we then see is that he persists.

He mixes some other gestures in there, he gives a bit of an object

shake, and the big scratching tends to be an invitation for grooming,

and the object shake is about, "move yourself".

So, he's basically saying, "Come over here,

"I would quite like to groom you."

And she's sort of thinking about it.

And then what you see is that she then comes down the tree,

and approaches over to him, and they have a lovely little groom

for a while.

And actually this worked out really well for him,

because about half an hour later they disappeared off

and weren't seen for a couple of weeks, and came back,

and we're trying to work out if she's now pregnant.

So, fingers crossed.

'So far, Cat has doubled the number

'of previously recorded chimp gestures, confirming 66 to date.

'Thanks to her work, we now have a chimp dictionary.'

"Can you move over there, please?"

"I'd like you to groom me, please."

"Climb aboard."

"Can you feed me, please?"

"Sorry, let's make up."

Just as with humans,

over half of all chimp communication is non-vocal.

And around a third of the gestures recorded so far

are similar to ones we use.

They're seen in all chimps, and are part of what make these apes great.

'Cat's painstaking research has given me

'a rare, intimate glimpse of family life.

'What I've seen is that chimps constantly communicate

'using body language.'

A simple scratch, grunt or wave can actually be laden with meaning.

The other thing that's struck me is how similar a lot of chimp gestures

are to our own, especially with their nearest and dearest.

'So far, I've seen the key role that communication plays

'in different groups of animals.

'But what I want to see now is how they communicate one on one.

'Because, with the very survival of the species dependant

'on finding a mate, some creatures have extremely sophisticated

'methods of attracting the opposite sex.

'To find out more,

'I've travelled 7,000 miles to North America, swapping Africa

'for a meadow in Massachusetts.'

I'm looking for a couple of scientists who have learned to speak

to a strange little bug using the language of light.

'It's midsummer - the highlight of the North American firefly's year.

'They're about to begin an annual two-week dating frenzy.'

-So, what is our temperature tonight so far?

-79 Fahrenheit.

'Dr Chris Cratsley and Professor Andy Moiseff are here to help me

'unlock the secrets of their mating rituals.'

Hello there, I'm Lucy.

-Hi, Lucy. I'm Chris.

-Chris, nice to meet you.

-Andy.

-Hi, Andy. Are you telling me we can really speak to a firefly?

-We're going to try!

-Really?! Do they chat back?

-Yes.

In the North American fireflies, there is dialogue,

-a communication between males and females.

-How do I speak to them?

Well, we're going to do it a couple of different ways.

We can use something as simple as a pen-light to flash as a female.

But we also have another device here - the firefly fishing rod,

and this will let us get a bit higher.

It can fly around and be a male flashing,

and look for females responding in the vegetation.

So the light display is all about mating, basically.

It's kind of like a firefly singles bar

-that we're going to visit tonight.

-Yes, that's right.

Actually a type of beetle,

most of the firefly's two-year life span is spent underground.

After hatching, they live as adults for just two weeks.

There are nearly 2,000 species worldwide.

Almost all have developed their own specific flash pattern,

and it's used for just one thing - attracting the perfect partner.

There are at least five different species in this meadow alone,

all broadcasting in their own unique languages.

It's a bit like trying to speed date in an airport departure lounge.

'Now, I want to investigate how these flirtatious flashes work.'

I thought I saw one over there.

Oh, I can see one there! I'm going to try and get that one.

That's closer, you might be able to catch that one with the net.

I'm sure... Did I do that too viciously?

No, you can be as vicious as you want.

But try to get the net under it, so that it falls...

Oh, I can see... Oh, my goodness me, there he is!

Look. I've caught my very first firefly.

Ooh! Where'd he go?

He's flashing down my shirt!

This is the wrong kind of lady that you're after.

Let's get him in the jar. Shall we get him in the jar?

So, now it's contained, we can see that that powerful light

is coming from a tiny lantern on the firefly's underside,

and it can angle that lantern to point the light,

and therefore the chat, at whoever it fancies.

And the light itself is bioluminescence, or living light,

and it's produced by a chemical reaction,

and it's incredibly energy efficient.

The firefly is one of only a handful of land animals to use

bioluminescence. But underwater...

it's a very different story.

90% of deep sea marine life

is thought to produce bioluminescence...

..using it to light their way, locate friends,

or, like the firefly, to speak to potential mates.

The darkest depths of the world's oceans are the backdrop

for one of nature's most impressive lightshows.

Back on land, I want to see

if I can get to grips with this luminous seduction technique.

We're going to have to switch now to special low-light cameras,

because our lights are disturbing the fireflies

and putting them off their chat.

What are we looking at here?

Pretty much everything you see are males. Because the males

will come out first, and at this point in the season

-there are many more of them than there are females.

-Ah!

-The kind of ratio I like.

-HE LAUGHS

And so they will be out advertising, cruising looking for females.

They'll flash and then they'll look for a response from the females

somewhere below them in the vegetation.

Males and females have different flash rates. But thankfully,

Chris speaks all forms of firefly, fluently.

What I want you to try and be is a male firefly

that flashes every eight seconds or so.

'My first date is with a female Photinus Ignites.

'I'm using Chris' LED fishing rod to

'try and chat one up by mimicking a male.'

You've got some competition out here because there's other male fireflies

around that are going to be trying to flash to these females as well.

'Most females can't fly, instead focusing all their energy

'on egg production,

'leaving the males, like me, to do all the chasing.'

Oh, I got her interested. How long do I wait? Tell me when.

-Tell me when.

-Go ahead.

Yeah. Hello.

She responded to someone else

and he very quickly produced another flash right after her response.

-He's much better at it than I am.

-That's him again.

-Oh, that's him.

-He's getting really close to her.

-Yeah, he's competing with you.

There she's responded to him.

-They're getting really close to each other.

-We still do have another

-female over here.

-OK, I'm going to give her a flash.

-There she is.

-OK, now don't go too close to her.

-OK.

She's being very picky, isn't she?

She's being very picky. Is it my technique?

Your struggles are not that unusual as a male firefly.

I feel the pain of the male firefly.

This has given me a window into their world

and they're very finicky these girls, they're hard to please.

I've been rejected.

Female fireflies are real flirts, often chatting up 10 males at a time

before finally committing to Mr Right.

But having failed to attract any interest, I'm going

to swap teams, and try my luck with the boys.

For this particular species, if we want to mimic a female,

we should flash four seconds after we see a male flash

and so let's see if we...

Here's one that flashed right here. Let's see if we can mimic a female.

Now the female flashes are a little bit longer in duration than

the male flashes and of course,

if we're using a pen-light like this, we have to muffle

it down in the vegetation because that's where the females will be.

-Ready to try to talk to the fireflies?

-I'm ready to give it a go.

-Now what do I do?

-So watch for a male flash.

-Try flashing about three seconds after it's flashed.

-OK.

Come on, baby.

-Pick me.

-That's a good sign when it keeps flashing back.

-Come on over!

-Hello!

-And you know they can't hear you.

I'm actually having a conversation with a firefly.

In fact, I'm not just having a conversation, I'm chatting it up.

Flash. Yeah, flash back, I'm interested.

This is extremely awkward

but the male firefly that I was just chatting up is now being eaten

by a spider so it's an abrupt end to our conversation.

I can't watch. It's too sad.

After two fireflies do manage to mate,

they'll go their separate ways.

Over the course of the next two weeks, their lanterns will

steadily dim. Until finally, their light goes out for good.

It's been a bit of a revelation to discover that you can actually

speak to a firefly quite easily.

All you really need is a pen-light and quite a bit of patience and

you have to know the specific Morse code of the firefly and you're away.

You're having a chat with an animal.

But not all animals are

so rigid in their dating rituals.

I've come to meet the red deer,

who take a more flexible approach to flirting

and rather than some far flung exotic location,

the best place to see their behaviour is just outside Bristol.

The females here at Ashton Court are spoiled for choice

because there's about 10 males in these grounds

and now it's the start of the rutting season

and the stags begin these ritualised displays of dominance

in order for them to take control of the ladies. But the ladies

are choosing the stags as much based on how they sound as how they look.

Male and female deer live separately most of the time,

only coming together for the annual two month rutting season.

The males then battle it out to win exclusive rights

to a whole harem of females.

Red Deer Stags are impressive animals on the outside

and on the inside they've evolved a special physiology

that allows them to turn on the charm.

STAG ROARS

'Dr David Reby is a pioneer in the study of vocal communication.'

ROARING CONTINUES

'By analysing and artificially adjusting their calls,

'he's found out what makes a stag irresistible.'

So, David,

in your studies, you manipulate the stags voices to make them sexier?

-Yes.

-Can you do the same thing with my voice?

Yes. What I'm going to do is record your voice. OK.

This is Lucy. Turn me into a sexy stag.

-Shall we play this?

-Yes, please.

DEEP VOICE: This is Lucy. Turn me into a sexy stag.

God! I really do sound like a man, that's so weird.

'What David's done is lowered the resonance of my voice.

'The acoustical quality, created by reverberations in the throat.

STAG ROARS

Lady deer like a roar with lower resonance,

because it should mean a bigger stag and therefore stronger offspring.

'To find out how important the right roar can be,

'David and I are going to conduct an experiment.

'First we're going to play the call of a young adult male.'

RECORDING OF A ROAR PLAYS

There's little response from the resident stag.

And his harem are even less impressed.

You've just played the roar of a stag

that's probably smaller than him.

So he doesn't need to put a lot of effort into his response.

Certainly I don't expect him to leave his harem and come over here.

'So how can a young buck ever hope to win over

'these hard-to-please ladies? David thinks they've developed

'a trick to lower the resonance of their roars.'

What they do is they lower their larynx further.

The larynx is the voice-box which is the equivalent

of my Adam's apple here and, when they roar, they also have

the ability of lowering the larynx all the way down to the sternum.

-So they sound bigger...

-Yes.

-..which is cheating basically.

Absolutely.

I would say they give an exaggerated impression of their body size.

They sound bigger than a deer should but they all do it.

By pulling down the larynx, deer can increase

the length of their vocal tract, making them sound up to 40% larger.

And to see just how effective this can be,

we're bringing out the big guns.

I'm going to play a roar

where the resonances have been much lowered.

DEEPER ROAR PLAYS

Well, we've definitely got the girls' attention.

STAG ROARS

He's clearly now quite worried.

ROARING CONTINUES

It looks like...

Are they leaving? Yes, they are, they're starting to leave.

He's lost about a third of his harem now.

You can hear his roaring,

trying to do something about what is happening to his harem.

'He's lost the attention of his ladies...for now.

'With no real rival around, they will return to the resident stag.

'But this isn't just a glimpse into the private lives of deer.

'Because the ability to manipulate resonance

'has long since thought to be unique to humans.'

MUSIC: "You're The First, The Last, My Everything" - Barry White

'Now David's work may have proved

'that we first evolved it to impress the opposite sex.'

Recent findings have shown that humans, just like deer,

associate bassier voices with stronger, more virile men.

STAG ROARS

Deer aren't the only animal to choose their mates

based on the sound of their voice.

I've come to Panama in Central America...

..to meet a fascinating little creature who can pick out

prince charming from a forest full of frogs.

The tungara frog breeds at night,

in and around bodies of fresh water, so I've come to

the Gamboa rainforest with amphibian communication expert Dr Ryan Taylor.

The thing is, if you study frogs,

you're not allowed to use mosquito repellent because, if you do,

it upsets the frogs because they've got really sensitive skin.

So we are out here in a swarm of mosquitoes

with absolutely no protection.

-In fact, hang on a second... I'm just going to...

-Ow!

I'm not sure if that was better or not.

The tiny tungara is just over an inch long,

weighs less than two grams

and is one of the most common frogs in Central America.

I can hear hundreds of them in this small patch of swamp alone.

It sounds like a ray gun fight.

While most frogs are famous for their croak, the tungara is unusual

in that it has a two-part mating call.

-Can you do a tungara frog?

-I can.

HE IMPERSONATES FROG

SHE IMPERSONATES FROG

That's so not right, is it?

The name tungara is onomatopoeia for the sound that they make,

-so tun-ga-ra.

-Tun-ga-ra. That makes sense. Tun-ga-ra.

Male tungaras outnumber the ladies by ten to one.

And whilst they may all sound the same to us, to a female tungara,

the perfect call is an important factor in finding the right mate.

But in this cacophony of calls, how can she match

the croak that catches her attention to the right frog?

The males are calling.

You can actually see that vocal sac expanding whilst he's calling.

Females seem to integrate both the calls

and the movement of that vocal sac into assessing potential mates.

So in order to work out who's saying what,

the females might be lip reading or vocal sac reading to be precise.

To put this theory to the test,

we need a lady volunteer to take back to the lab.

Oh, got it. Ryan's promised to bring her home afterwards.

Now all we need is a male,

and, back at the lab, I think I've found one.

'Dr Barrett Klein is the only scientist in the world

'to specialise in made-to-measure robot frogs.' Why a robot?

Excellent question. Why not just rely on their real-life counterparts?

So if we depend on males, real males,

in studying how they communicate with females, we're very limited.

If we make a robot, we can do the impossible.

So by building a fake frog,

-we can get to the truth of their communication.

-Exactly.

Do you think you're an obsessive, Barratt?

Well, I think when it comes to building robofrogs, it might pay

to be pernickety to effectively fool a female with a doppelganger.

Model made.

Time to find out if the females are locating the male

whose call they like by matching it to the movement of the vocal sac.

As tungaras are nocturnal, we place our female in a dimly lit room,

between two speakers.

Both will play the same male call,

but stationed in front of one of them will be our model.

If Ryan's right, the sight and sound of robofrog

should prove irresistible.

So she's sitting in there thinking, "Oh, I can hear gentlemen."

-Indeed.

-She's heading towards the speaker quite fast.

Oh, no!

She's... No, she's going the other way,

she's heading towards robofrog. Come on, girl!

You can see him singing sweet songs of love. Go to him.

That's a decision, isn't it?

So she was able to locate the sound that she liked with

the visual that she liked and put the two together.

-Yes. Absolutely.

-Was it good for you, Ryan?

-More than you can imagine...

'It may seem obvious that the female would automatically assume

'the call was coming from the only frog in the room but Ryan is

'sure that it's all down to sac and sound being in perfect sync.

'To see if he's right, we're going to try the experiment again,

'but this time, robofrog's sac will be well out of whack.'

We've altered the timing of the vocal sac artificially,

so that it doesn't match the timing of the call.

-Shall we go for it?

-Sure.

She turned towards the speaker. Shocking behaviour!

I can't believe that she's going to choose the speaker.

Oh, no, hang on, she's changing her mind,

she's going towards robofrog now.

That was close, she came very close to robofrog then, very close,

but she's heading towards the speaker now.

She gave it a bump.

She gave the speaker a bump. We would call that a choice.

'Our lady knows that robofrog can't be the one making the noise.

'So she's searching the area

'for the real source of this sexy call.'

What the female is telling us is that it's really important

that the timing of the vocal sac matches the timing of the call.

-So it's a really strong cue, that visual cue.

-It is.

Like humans at a cocktail party, when you're trying to have

a conversation and there's all this background noise, by reading lips

it improves our speech comprehension and we think that the females

-may be doing something similar.

-She keeps going back to that speaker.

She's been back to that speaker about five times now.

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

This sophisticated system has evolved specifically

to help the tungaras find the right mate.

But what it's shown me, is that animals, just like humans,

combine information from different senses in order to communicate.

The first leg of my journey is almost at an end.

'There's just one thing I need to see.

'I've travelled 3,000 miles to Berkeley, California.

'To meet a tiny creature,

'who's had a huge impact on the study of animal communication.

'And Professor Damian Elias is going to introduce me.'

So you realise, Damian, that I've never seen a jumping spider before.

So this is the first time I've seen one.

So jumping spiders are absolutely spectacular but they're very small.

-Let me show you a male.

-Is it OK for me to...?

They're very cute, aren't they?

I like thinking that if they were the size of birds

they would be even more popular than birds.

They're just so beautiful and so wonderful.

I'm looking forward to seeing them under the microscope and getting a better look.

There, that's brilliant. OK, now you can see him.

'There are 5,000 species of jumping spider worldwide.

'They all have different characteristics,

'but one thing they have in common

'is the ability to perform elaborate courtship dances.

'Damian wants to show me the jumping spider's moves,

'but first, we need a dance floor.'

Damian, why have you just handed me a pair of ladies tights?

Well, surprisingly, one of the best surfaces

we found for males to dance on, one of the best dance-floors is actually

-a pair of ladies tights.

-Where did these tights come from, Damian?

These tights came from my girlfriend's mother.

Surreptitiously at one point.

Here you go.

We have one spider disco dance floor.

'Next we need a dance partner.

'And luckily, Damian has a freezer full of dead females.'

We call this our graveyard of females.

-Aw! There's some good specimens in here.

-Yeah.

That is fantastic.

One female puppet ready to flirt with a male.

'First we have to attach her to the dance floor,

'and Damien's going to let me be the puppet master.'

Now, as you turn the dial, you can see that the female turns with it.

I'm going to have to learn how to move like a female spider

if I'm going to get that male to dance for me, basically.

How do I do that?

You want the puppet to show a lot of interest to lock her gaze at the male

and just track exactly the directions of where he's going.

-So it's all in the eyes.

-It's all in the eyes.

-Really?

Right there, stop for a little bit.

I'm locking eyes with him. He's waving his hands at me!

It is a very nervous movement, isn't it? That kind of dodging around.

Females are much larger than the males and so cannibalism

is actually quite a common occurrence in jumping spiders.

So the pressure's on for Mr Spider. In the wild,

if he put a foot wrong, she'd make a meal out of him.

I like you.

I surrender to your beauty.

The fancy footwork seems to be getting him nowhere.

But there's more to this dance than meets the eye.

RUMBLING

That's incredible, that noise.

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

-Yes, he is.

-This sound is created by the spider's abdomen

vibrating against the dance floor.

RUMBLING CONTINUES

'Using a powerful microphone, we're able to reveal

'the most critical aspect of this display.

'The performance is over.

'Time for the male to make his move.

'But for this poor fellow, it's the brush off.'

That was extraordinary. It was like having a bumble bee trapped inside

-a jar.

-Most things that are small use this type of communication and

it's basically been completely hidden to us until technology came along.

The scales fall from your eyes and all of a sudden you see

all of these things that you never, never knew existed

or scientists never ever expected.

That was incredibly exciting. I've just had a spider

not only dance for me, but sing his heart out

in the most extraordinary manner in a secret seismic language.

The jumping spider isn't the only creature

to use seismic communication.

Elephants can detect vibrations through

the skin on their massive feet from an astonishing 16 kilometres away.

But what our friend the spider shows

is that tiny creatures like insects and arachnids

have found a way to make their presence felt.

Leaf cutter ants send vibrations through plants to recruit

other colony members. Termites use them to raise the alarm

when predators are spotted.

In fact, it's estimated that

more than 90% of insects use seismic signals.

Their messages may only make it a few metres,

but for creatures this small, that's communicating on a grand scale.

I started out on this epic journey wanting to fulfil a childhood dream

of talking to the animals and I've totally succeeded...

thanks to the help of some slightly nutty professors.

But their ingenuity and dedication have given me access

to secret worlds filled with noises we can't hear,

vibrations we can't feel and taught me languages I never knew existed.

It's the sheer inventiveness of animal communication

that has impressed me most. The way that it's evolved

to overcome extraordinary hurdles to ensure that, like us,

animals find and keep in touch with the ones they love.

'Next time, I'll discover

'just how sophisticated animal-speak really is.'

Oh, my word! They're coming towards us.

'And find out exactly what they're saying...'

They're definitely, definitely telling me to leave.

'..to enemies...'

It's the first example of infra red communication in animals.

'..friends...' This is amazing. So this is a dolphin greeting.

'..and even their neighbours.'

The second they heard that, they dashed to cover.

So we've just seen a meerkat neighbourhood watch scheme.