0:00:02 > 0:00:04From the loudest roar...
0:00:04 > 0:00:05ROARING
0:00:05 > 0:00:08..to the smallest squeak...
0:00:08 > 0:00:10SQUEAKING
0:00:10 > 0:00:12..all across the world, animals are talking
0:00:12 > 0:00:16to each other in extraordinary ways.
0:00:16 > 0:00:17Ever since I was little,
0:00:17 > 0:00:20I've wanted to become a real-life Dr Doolittle and
0:00:20 > 0:00:24talk to the animals - I think it's something we'd all secretly love.
0:00:26 > 0:00:31'I'm Lucy Cooke, a zoologist on a quest to crack the animal code.'
0:00:35 > 0:00:38New discoveries are being made all the time,
0:00:38 > 0:00:43and I'm going on a worldwide journey to unravel animal conversations,
0:00:43 > 0:00:47and hopefully unlock some of the secrets of their lives.
0:00:47 > 0:00:50Using the latest scientific findings,
0:00:50 > 0:00:53I'm going to listen in on a hidden world.
0:00:55 > 0:00:57(My heart is going like the clappers!)
0:00:57 > 0:00:59'From secret seismic chatter...'
0:01:00 > 0:01:02He's making that noise to attract her, is he?
0:01:02 > 0:01:06'..to flirting in the language of light...'
0:01:06 > 0:01:09I'm not just having a conversation - I'm chatting it up!
0:01:09 > 0:01:12'..I'll discover how animals communicate...'
0:01:12 > 0:01:16This is the first example we know of of infrared communication.
0:01:16 > 0:01:19'..and reveal exactly what they're saying.'
0:01:21 > 0:01:23This is amazing! So, this is a dolphin greeting.
0:01:25 > 0:01:27It's like a welcoming party.
0:01:40 > 0:01:43'Whether they live in families, herds or packs,
0:01:43 > 0:01:49'communication is at its richest in animals that live in groups,
0:01:49 > 0:01:53'and I want to find out about the sophisticated methods they use
0:01:53 > 0:01:56'to get their messages across.'
0:01:58 > 0:02:01So I've come here to East Africa
0:02:01 > 0:02:05to meet three very different animal clans with three
0:02:05 > 0:02:09very different ways of keeping in touch. I'm going to eavesdrop
0:02:09 > 0:02:11and even join in.
0:02:12 > 0:02:15'My first stop is the Queen Elizabeth National Park
0:02:15 > 0:02:20'in Uganda - home to one of the most social creatures on the planet.
0:02:20 > 0:02:24'Not the mighty lion, nor the graceful giraffe.
0:02:24 > 0:02:26'My epic journey begins...
0:02:27 > 0:02:29'..with the banded mongoose.'
0:02:31 > 0:02:33Oh, look at them.
0:02:37 > 0:02:39Aw. Hello.
0:02:41 > 0:02:43These are the banded mongoose.
0:02:43 > 0:02:45As you can see, they're very curious.
0:02:45 > 0:02:47Look at this.
0:02:47 > 0:02:49Hello. Hello!
0:02:50 > 0:02:53And that's because these ones are habituated to scientists,
0:02:53 > 0:02:56so they're used to having humans around.
0:02:56 > 0:02:58This is one extended family,
0:02:58 > 0:03:02and as you can hear they're really chatty characters.
0:03:02 > 0:03:05There's a lot of gossiping going on.
0:03:05 > 0:03:07This one's getting a bath.
0:03:11 > 0:03:14'The banded mongoose is native to Africa,
0:03:14 > 0:03:18'and, like their more famous cousins the meerkats, live cooperatively
0:03:18 > 0:03:20'in clans of up to 40.
0:03:20 > 0:03:24'But, uniquely, mongoose females within the group even give
0:03:24 > 0:03:28'birth on the same day and their young are raised collectively.
0:03:28 > 0:03:31'Dr Emma Vitikainen is part of a team who study
0:03:31 > 0:03:34'how these animals live, and communicate.'
0:03:35 > 0:03:38So, Emma, what I've noticed about them,
0:03:38 > 0:03:40which I love, is they're so noisy.
0:03:40 > 0:03:43They just seem to be chatting the whole time.
0:03:43 > 0:03:44They really are.
0:03:44 > 0:03:47They constantly make little noises. They've got a very complex
0:03:47 > 0:03:51social life and need to coordinate carefully in order to be successful.
0:03:51 > 0:03:53So, if you're just a lone animal,
0:03:53 > 0:03:56you don't need to have great communication skills.
0:03:56 > 0:03:59But if you do have a very complex society then you need to have
0:03:59 > 0:04:03- complex language abilities, is that right?- Absolutely.
0:04:03 > 0:04:04They've got lots to talk about
0:04:04 > 0:04:06because they do everything as a group.
0:04:06 > 0:04:09Starting from foraging, they find food together.
0:04:09 > 0:04:12And then there's all the duties for childcare -
0:04:12 > 0:04:16who does the baby-sitting, who's your escort, who do you need to stick by?
0:04:16 > 0:04:17All these very complex behaviours,
0:04:17 > 0:04:20and communication really is key in co-ordinating all that
0:04:20 > 0:04:22within the group.
0:04:22 > 0:04:25'So, to keep their structured society running smoothly,
0:04:25 > 0:04:28'the mongooses have become very vocal indeed.'
0:04:29 > 0:04:33They really are insanely chatty.
0:04:33 > 0:04:34CHIRPING
0:04:34 > 0:04:39To begin with, it's a cacophony of squeaking, but now I've been
0:04:39 > 0:04:45here, I can actually hear there are different squeaks going on.
0:04:47 > 0:04:50'By studying the sounds mongooses make in different
0:04:50 > 0:04:53'situations, the scientists here have decoded
0:04:53 > 0:04:55'several different noises, or calls.'
0:05:05 > 0:05:08'But there's one call that's absolutely vital
0:05:08 > 0:05:12'to the wellbeing of the clan - the contact call.
0:05:12 > 0:05:15'A signal broadcast by each individual to maintain
0:05:15 > 0:05:18'constant contact with the group.
0:05:18 > 0:05:21'To try and capture some of these calls, Emma's sent me
0:05:21 > 0:05:23'out with a microphone.'
0:05:23 > 0:05:25This is going to be difficult, I can tell.
0:05:31 > 0:05:34Oh, don't run off!
0:05:34 > 0:05:38It's a wonder science has managed to find out anything
0:05:38 > 0:05:39about mongoose calls.
0:05:42 > 0:05:45'Eventually, I manage to pick up a few squeaks
0:05:45 > 0:05:48'and take them back to Emma.'
0:05:48 > 0:05:52- So, Emma, how did I do?- Well, you actually did pretty well, I thought.
0:05:52 > 0:05:55There's lots of sound files and lots of background noise.
0:05:55 > 0:05:59There's lots of you walking around, but I managed to pick a piece
0:05:59 > 0:06:02where there is really quite a good contact call.
0:06:02 > 0:06:05MONGOOSE CONTACT CALL
0:06:05 > 0:06:07I did it, I got you a clean call, that's fantastic.
0:06:07 > 0:06:09So, now what does it mean?
0:06:09 > 0:06:13In order to see that, I've created a spectrogram,
0:06:13 > 0:06:15and this is the end result.
0:06:15 > 0:06:200.5 seconds long. See, there's two bits in the call.
0:06:20 > 0:06:23This is what we call the noisy part of the call,
0:06:23 > 0:06:27and the harmonic part of the call.
0:06:27 > 0:06:30So, that one tiny squeak that I recorded
0:06:30 > 0:06:34contains two separate calls, basically.
0:06:34 > 0:06:38Yes. The first part, that tells other mongooses who is calling.
0:06:38 > 0:06:42The second part is basically shouting out what it's doing.
0:06:42 > 0:06:46That's wonderful. I just love it.
0:06:46 > 0:06:50So much information is contained within a call
0:06:50 > 0:06:52that's just half a second long.
0:06:52 > 0:06:55So, how many different types of contact call have been established?
0:06:55 > 0:06:57There's three different types.
0:06:57 > 0:06:59So, the first one and the most simple one
0:06:59 > 0:07:01is when a mongoose is digging.
0:07:01 > 0:07:03MONGOOSE CALLS
0:07:06 > 0:07:09Then when they're foraging, finding food, with their nose
0:07:09 > 0:07:10on the ground, it's searching.
0:07:10 > 0:07:12MONGOOSE CALLS
0:07:13 > 0:07:16And when they're just on the move,
0:07:16 > 0:07:19nose up, moving from one patch to another,
0:07:19 > 0:07:20that's the third type of call.
0:07:20 > 0:07:22MONGOOSE CALLS
0:07:22 > 0:07:26This simple-sounding call is packed full of information.
0:07:26 > 0:07:31Every single mongoose has its own unique signature and, when placed
0:07:31 > 0:07:35in front of what it's doing, is used to update others on its status.
0:07:37 > 0:07:39So far, contact calls have been confirmed
0:07:39 > 0:07:42for three of the most common mongoose activities.
0:07:44 > 0:07:46If you think about it,
0:07:46 > 0:07:49if you're a mongoose, you've got to stay in a pack.
0:07:49 > 0:07:52A lot of the time, they're foraging for bugs and beetles
0:07:52 > 0:07:55and they've got their head in the ground, so this noise is the
0:07:55 > 0:08:00best way for them to keep in touch, to keep in contact with each other.
0:08:01 > 0:08:05This is social networking, mongoose style.
0:08:10 > 0:08:13But these sophisticated squeaks aren't the only method
0:08:13 > 0:08:15the mongooses use to keep in touch.
0:08:15 > 0:08:19'They're communicating constantly in another language altogether.
0:08:19 > 0:08:22'To find out more, we need to gather the group,
0:08:22 > 0:08:26'and there's one sure-fire way to get their attention.'
0:08:26 > 0:08:29Who fancies a little bit of water? OK?
0:08:32 > 0:08:34SQUEAKING
0:08:36 > 0:08:39'At first, the pack react vocally.'
0:08:41 > 0:08:45Wow! That is the sound of a mongoose party!
0:08:46 > 0:08:49But then the group begin using an entirely different method
0:08:49 > 0:08:51of communication - scent.
0:08:58 > 0:09:00That's amazing.
0:09:00 > 0:09:03So, after the water call, there is a frenzy of scent marking with
0:09:03 > 0:09:05even the little pups getting involved in it.
0:09:05 > 0:09:08- Yeah.- So them rubbing their bottoms on the branch is them
0:09:08 > 0:09:10leaving their scent, basically.
0:09:10 > 0:09:13Yes, everyone has to join in and it's really like building a team spirit.
0:09:13 > 0:09:15Everyone has to smell the same.
0:09:15 > 0:09:19So, it seems like scent is really important to mongooses.
0:09:19 > 0:09:22It's an essential part of everything they do.
0:09:23 > 0:09:28Whether it's marking out territory, establishing hierarchy, or
0:09:28 > 0:09:33keeping in touch, scent is essential in all aspects of mongoose life.
0:09:35 > 0:09:40In fact, scent, or chemical communication, is used by almost
0:09:40 > 0:09:47every animal on the planet, from the primitive, to the most complex.
0:09:49 > 0:09:53Some insects leave pheromone trails to be followed by their fellows.
0:09:54 > 0:09:57Certain moths can sniff out a potential mate
0:09:57 > 0:10:00from up to seven miles away.
0:10:01 > 0:10:04Even underwater, fish use smell to stay in formation
0:10:04 > 0:10:06with their friends.
0:10:06 > 0:10:10These invisible messages are all around us.
0:10:15 > 0:10:17Well, this has been a great place to start.
0:10:17 > 0:10:21The mongoose family is the most organised I've ever met,
0:10:21 > 0:10:25and what's fascinating is how much they have to communicate
0:10:25 > 0:10:28in order to keep that well-oiled machine ticking over.
0:10:28 > 0:10:30But the real eye-opener
0:10:30 > 0:10:34is how animal speak is far more than just cries and calls.
0:10:34 > 0:10:36They're communicating constantly
0:10:36 > 0:10:39in ways that we can neither see, nor hear.
0:10:40 > 0:10:45'I want to find out more about these hidden worlds,
0:10:45 > 0:10:49'so I'm travelling 300 miles to Murchison Falls on the Nile.
0:10:50 > 0:10:54'In the animal kingdom, social groups come in all shapes and sizes,
0:10:54 > 0:10:58'so I'm switching from one of Africa's smallest mammals
0:10:58 > 0:11:00'to one of its largest...
0:11:02 > 0:11:03'..the hippopotamus.'
0:11:06 > 0:11:10Almost a third of Uganda is made up of bodies of fresh water,
0:11:10 > 0:11:13making it the perfect place to study hippos.
0:11:17 > 0:11:19'This 25-mile stretch of river alone
0:11:19 > 0:11:23'is packed with an estimated 15,000 of them.'
0:11:24 > 0:11:28I love hippos, they're such massive oddballs.
0:11:28 > 0:11:32Your average hippo weighs about the same as a family car.
0:11:32 > 0:11:36They have enormous powerful jaws and long, sharp incisors
0:11:36 > 0:11:41and are famously aggressive and, in fact, they are supposedly
0:11:41 > 0:11:45responsible for more human deaths than any other African animal.
0:11:45 > 0:11:51But for a bunch of grumpy misfits, they're incredibly talkative.
0:11:51 > 0:11:56So I'm hoping to be able to join in, and have a chat with them myself.
0:12:02 > 0:12:05'To help me get the conversation started, I've met up with Professor
0:12:05 > 0:12:10'Bill Barklow, the world's leading expert in hippo communication.'
0:12:12 > 0:12:15I can count 27 hippos right there.
0:12:15 > 0:12:19'He's been listening in on them for almost 30 years.'
0:12:19 > 0:12:23Every one of them capable of making a 120 decibel sound.
0:12:23 > 0:12:25That's as loud as being at a rock concert
0:12:25 > 0:12:27- and standing next to the speaker.- It is.
0:12:27 > 0:12:29Yes, and all at the same time. It's quite an experience.
0:12:35 > 0:12:38Hippos live in large groups or pods, which
0:12:38 > 0:12:45can contain up to 100 individuals, all clamouring to keep in touch.
0:12:46 > 0:12:50So, what's the repertoire like of a hippo?
0:12:50 > 0:12:53Up to 25 or 30 different sounds that they routinely make.
0:12:53 > 0:12:57All kinds of screams and growls and grunts and whines.
0:12:57 > 0:12:59Pre-linguistic mammal sounds.
0:12:59 > 0:13:01Sounds that we all know about.
0:13:01 > 0:13:04- Growl means what to you? - Growl means you're angry.
0:13:04 > 0:13:06Yeah, and if I go... HE WHINES
0:13:06 > 0:13:09- Then you're being submissive. - Submissive or frightened.
0:13:09 > 0:13:11And if I go... HE SHRIEKS
0:13:11 > 0:13:12What would you say that is?
0:13:12 > 0:13:15- Ha-ha! You're trying to frighten me! - I know. So you were frightened.
0:13:17 > 0:13:20They do make some sounds that are apparently only made under water.
0:13:20 > 0:13:24One of them is a whine, a very high-pitched "wooooo!"
0:13:24 > 0:13:26And clicks, not just one click but...
0:13:26 > 0:13:28HE CLICKS RAPIDLY
0:13:28 > 0:13:31Like that, and there's a huge range of variations of these things
0:13:31 > 0:13:35that they can make under water, it's just hilarious to listen to.
0:13:35 > 0:13:37'Bill's going to help me eavesdrop
0:13:37 > 0:13:42'on some of these hidden hippo sounds using a hydrophone,
0:13:42 > 0:13:46'an underwater microphone connected to a speaker on the boat.'
0:13:47 > 0:13:50It's like we're going fishing for hippo sounds.
0:13:58 > 0:13:59Keep going.
0:14:04 > 0:14:06CROAKING There, did you hear that?
0:14:06 > 0:14:07That was a croak.
0:14:09 > 0:14:12That croak sounded like a frog.
0:14:12 > 0:14:15It's just like a frog, so I named it a croak and they're a very common
0:14:15 > 0:14:18sound, probably the most common underwater sound that hippos make.
0:14:18 > 0:14:21They're made mostly by the little ones, calves which will play
0:14:21 > 0:14:25with one another underwater, often with one female protecting them.
0:14:25 > 0:14:29It's a creching behaviour where one female will take care of other
0:14:29 > 0:14:31females' babies for an afternoon.
0:14:31 > 0:14:34The water is the colour of coffee with cream in it,
0:14:34 > 0:14:36so you can't see anything more than a foot away.
0:14:36 > 0:14:40So she only has her ears to keep track of the little ones.
0:14:40 > 0:14:43So, that croak is basically a hippo baby monitoring system.
0:14:43 > 0:14:45That's precisely what it is, yes.
0:14:45 > 0:14:47That's fantastic - and what I love is that it's showing a more caring
0:14:47 > 0:14:50- side to the hippo. - Yes, they care for their babies.
0:14:52 > 0:14:55'Bill's findings have given us a remarkable insight
0:14:55 > 0:14:59'into how hippos keep in touch underwater.
0:15:01 > 0:15:04'But his work has also uncovered something completely
0:15:04 > 0:15:06'unique in the animal kingdom...
0:15:09 > 0:15:13'..that hippos can communicate above and below water simultaneously.'
0:15:20 > 0:15:22I first saw hippos on a safari to Africa.
0:15:22 > 0:15:25Late in the afternoon they started to interact,
0:15:25 > 0:15:27the hippos did, and they started to call,
0:15:27 > 0:15:30and then I noticed that maybe five other hippos surfaced,
0:15:30 > 0:15:35came up to the surface, as if they'd heard an airborne sound underwater.
0:15:35 > 0:15:38And that, I thought, was breaking the laws of physics.
0:15:38 > 0:15:41We scientists live for the idea of something new,
0:15:41 > 0:15:43something that no-one else has ever heard before,
0:15:43 > 0:15:46and I thought, "I've got to check this out".
0:15:49 > 0:15:53'Bill calls this phenomenon amphibious communication...
0:15:55 > 0:15:58'..and he's devised an experiment to show me how it works.
0:16:00 > 0:16:04'We're going to play the call of a hippo from a different pod.
0:16:05 > 0:16:08'Hearing it should provoke the local residents into a chorus,
0:16:08 > 0:16:12'each stating that this territory belongs to them.'
0:16:14 > 0:16:18So, right now, it's a lovely, quiet evening here on the Nile.
0:16:18 > 0:16:22But I'm hoping to completely change all that by playing this call,
0:16:22 > 0:16:26which should start a contagious calling session
0:16:26 > 0:16:28of all the hippos in this area.
0:16:28 > 0:16:30So, let's see if it works...
0:16:30 > 0:16:32I'm about to say hello to the hippos.
0:16:33 > 0:16:37'Will the hippos hiding underwater get the message?'
0:16:37 > 0:16:40HIPPO CALLS ON TAPE
0:16:49 > 0:16:51GRUNTING
0:16:56 > 0:16:58'The dominant male takes the bait.'
0:17:05 > 0:17:08That was another one over there, wasn't it?
0:17:14 > 0:17:17There's heads popping up everywhere.
0:17:19 > 0:17:22'His call has set off a chain reaction.'
0:17:24 > 0:17:26That's fantastic how it spreads, isn't it?
0:17:26 > 0:17:29It's phenomenal. And you heard them out here, didn't you?
0:17:29 > 0:17:30- Yeah.- It's contagious.
0:17:33 > 0:17:36'Amphibious communication allows hippos on the surface to
0:17:36 > 0:17:40'contact their podmates, both above and below water,
0:17:40 > 0:17:45'at the same time. But how does it actually work?'
0:17:45 > 0:17:49So, the sound above water comes out of the nostrils.
0:17:49 > 0:17:52How does the sound get transmitted below water?
0:17:52 > 0:17:55The underwater sound is produced by a great roll of fat on their throat.
0:17:55 > 0:17:59So, when they make a sound with their larynx, vibrating the vocal
0:17:59 > 0:18:05cords, it passes through that fat without resistance into the water.
0:18:05 > 0:18:08So, it's a direct transmission from the throat into the water.
0:18:08 > 0:18:10'The noise travels from the voice box,
0:18:10 > 0:18:13'through the fat, straight into the water.
0:18:13 > 0:18:18'But making sound below the surface is only half the story.
0:18:18 > 0:18:22'Bill wondered whether, as with some marine mammals, their jawbone
0:18:22 > 0:18:24'was acting as a receiver for sound,
0:18:24 > 0:18:27'sending it straight to the inner ear.
0:18:27 > 0:18:30'Years later, he was proved right.
0:18:30 > 0:18:35'Genetic analysis has since shown that the hippo, a land mammal,
0:18:35 > 0:18:37'is in fact most closely related...
0:18:40 > 0:18:41'..to whales...
0:18:44 > 0:18:46'..and dolphins.'
0:18:48 > 0:18:52It's been a total revelation to discover that hippos
0:18:52 > 0:18:57can communicate above water and below water simultaneously,
0:18:57 > 0:18:59and they're the only animal that can do that.
0:18:59 > 0:19:03But what's really fascinating is that they're communicating using
0:19:03 > 0:19:05a technique that's used by their cousins the whales
0:19:05 > 0:19:07and dolphins far out at sea.
0:19:10 > 0:19:12And that is really remarkable.
0:19:14 > 0:19:16GRUNTING
0:19:17 > 0:19:21They just don't stop. It just doesn't stop.
0:19:34 > 0:19:37'Both hippos and mongooses have fascinating social lives,
0:19:37 > 0:19:41'but now I want to see how communication works in an animal
0:19:41 > 0:19:43'more similar to ourselves -
0:19:43 > 0:19:46'our closest genetic relative.
0:19:47 > 0:19:49'The chimpanzee.'
0:19:49 > 0:19:52Scientists have spent decades working with chimps,
0:19:52 > 0:19:55trying to teach them to talk to us.
0:19:55 > 0:19:57Some even learned sign language.
0:19:58 > 0:20:01But in order to truly understand their communication,
0:20:01 > 0:20:05we have to stop speaking human and start learning chimp.
0:20:10 > 0:20:14So I've come here, to Budongo National Forest in Uganda,
0:20:14 > 0:20:17one of the largest natural forests in east Africa
0:20:17 > 0:20:19where you can still see wild chimps.
0:20:21 > 0:20:24And I've been given permission to visit
0:20:24 > 0:20:27one of the world's greatest chimp communication centres.
0:20:27 > 0:20:29I can hardly wait.
0:20:31 > 0:20:34The team here is pioneering a completely new approach
0:20:34 > 0:20:37in the study of chimp communication,
0:20:37 > 0:20:42and Dr Cat Hobaiter is at the forefront of the work.
0:20:43 > 0:20:45We basically try to be non-existent.
0:20:45 > 0:20:49We try to be trees in the forest and we're not interacting with them,
0:20:49 > 0:20:51and they're very used to us, so we can follow them
0:20:51 > 0:20:54around the place without really disturbing their natural behaviour
0:20:54 > 0:20:57and just we sit quietly somewhere, don't interact with them and
0:20:57 > 0:21:00just let them get on with their lives and their communication.
0:21:00 > 0:21:04Right, so, it's really different to how things have been done before,
0:21:04 > 0:21:07- isn't it?- We don't want to change their behaviour
0:21:07 > 0:21:09and we don't want to know what they have to say to us,
0:21:09 > 0:21:12we want to know what they have to say to each other.
0:21:12 > 0:21:13'To see this approach in action,
0:21:13 > 0:21:16'I'll have to trek deep into the forest.
0:21:16 > 0:21:18'But with night about to fall,
0:21:18 > 0:21:21'my field trip will have to wait till morning.'
0:21:36 > 0:21:41It's six o'clock in the morning and the sun is just coming up,
0:21:41 > 0:21:43and we're going off to try and find the chimpanzees.
0:21:45 > 0:21:49To say I'm excited is a complete understatement.
0:21:50 > 0:21:53It's not every day that you get to fulfil
0:21:53 > 0:21:57one of your lifetime ambitions, and today is one of those days.
0:22:05 > 0:22:07CHIMPS CALL OUT
0:22:07 > 0:22:10My God! The sounds they make - it's extraordinary!
0:22:12 > 0:22:15It's like a welcoming party.
0:22:17 > 0:22:22'In fact, chimps have around 30 different calls, and, like humans,
0:22:22 > 0:22:27'they often reinforce their messages by combining them with gestures.
0:22:28 > 0:22:31'So, to truly understand what the chimps are saying,
0:22:31 > 0:22:34'we have to learn another language altogether -
0:22:34 > 0:22:36'body language.'
0:22:39 > 0:22:42- Is it a very intimate scene that we're watching?- It is.
0:22:42 > 0:22:45What's really lovely about these guys is that you've got a mum
0:22:45 > 0:22:48and all four of her children together.
0:22:48 > 0:22:50What they're doing is grooming each other.
0:22:50 > 0:22:53So what I'm looking for at the moment is all of the little gestures
0:22:53 > 0:22:56they use to each other.
0:22:56 > 0:22:59And they're grooming different parts of each other's bodies, so maybe,
0:22:59 > 0:23:03"I want to groom your arm over there so I'll give you a little nudge."
0:23:03 > 0:23:06They'll offer the arm and they'll groom here.
0:23:06 > 0:23:08'Through movement alone,
0:23:08 > 0:23:12'this family are issuing each other with a clear list of instructions.'
0:23:12 > 0:23:15These grooming gestures are a lot more subtle than I'd have expected.
0:23:15 > 0:23:18I'd never have guessed that that was communication.
0:23:18 > 0:23:22It's a little bit like if your mum's brushing your hair, she'll
0:23:22 > 0:23:26move your head to that side and you'll have to hold it in position.
0:23:26 > 0:23:29It's not just about picking you up and putting you over here,
0:23:29 > 0:23:31it's about asking you to move over there.
0:23:31 > 0:23:33A really close-knit family like this,
0:23:33 > 0:23:36they really don't need to say that much to each other.
0:23:36 > 0:23:37That's right.
0:23:37 > 0:23:41With your family, a look might convey an entire sentence
0:23:41 > 0:23:45because you know each other that well, so that's the equivalent
0:23:45 > 0:23:46- going on there.- Absolutely.
0:23:52 > 0:23:57It is an incredible privilege to be able to sit in their world
0:23:57 > 0:24:02really close to them and for them to just carry on conversing
0:24:02 > 0:24:07with each other. It means that you're really seeing
0:24:07 > 0:24:13their true behaviour and really listening to and witnessing
0:24:13 > 0:24:18incredibly intimate conversations and communication between them.
0:24:22 > 0:24:24'But in order to see some different gestures,
0:24:24 > 0:24:26'we need to find another group.'
0:24:30 > 0:24:32That's a new born baby up there.
0:24:32 > 0:24:34CHIMPS WHOOP AND CALL EXCITEDLY
0:24:38 > 0:24:39Today is the first day that she's
0:24:39 > 0:24:42come into the community with the baby.
0:24:42 > 0:24:46It's incredibly exciting, not just for us, but for all the chimps.
0:24:50 > 0:24:54I love the fact that they're like some big Italian family,
0:24:54 > 0:24:57all really fired up because there's a new baby around.
0:24:57 > 0:25:01And all these different groups are coming to visit the baby
0:25:01 > 0:25:03and check it out.
0:25:03 > 0:25:08But for that reason, we have to be very careful today,
0:25:08 > 0:25:12because there's a lot of emotion running high with the chimpanzees.
0:25:16 > 0:25:21'As we watch on, two males begin to make dramatic displays.
0:25:23 > 0:25:26GRUNTING AND SCREAMING
0:25:30 > 0:25:33(My heart is going like the clappers!)
0:25:39 > 0:25:41A chimp came barrelling through here.
0:25:41 > 0:25:44What happens to the males is when they get really excited -
0:25:44 > 0:25:47a bit like our goose bumps - all of their hair stands on end to
0:25:47 > 0:25:51make them look twice as big, and as he went through there
0:25:51 > 0:25:54he barrelled straight into the female with the brand-new baby.
0:25:54 > 0:25:57And of course she then panicked completely, as you would.
0:25:57 > 0:26:00Did you notice any gestures?
0:26:00 > 0:26:03Well, it's really hard to see in this dense undergrowth,
0:26:03 > 0:26:07but in that situation, I'm almost certain a really common gesture and
0:26:07 > 0:26:11something that's very familiar to us is that she would reach her hand out
0:26:11 > 0:26:14and that'll be it, they'll have made up
0:26:14 > 0:26:17and that's when everything calms back down again.
0:26:17 > 0:26:21It's lovely to see those little gestures that are so intuitive.
0:26:24 > 0:26:27'Things move so fast in the field,
0:26:27 > 0:26:30'it can be easy to miss the true significance of these gestures.
0:26:33 > 0:26:35'So, back at camp, Cat shows me footage
0:26:35 > 0:26:40'of a similar interaction between a new mother and an aggressive male.'
0:26:41 > 0:26:45What we've got here - he's basically threatening her,
0:26:45 > 0:26:47he's challenged her a little bit,
0:26:47 > 0:26:50so she decides to go and really communicate to him,
0:26:50 > 0:26:53just to make sure that he, hopefully, just leaves her alone.
0:26:53 > 0:26:56- And you see that she basically... - Oh, she stuck her hand out.
0:26:56 > 0:26:59..gives a beautiful little reach just over to him while looking at him
0:26:59 > 0:27:03and then she just keeps looking at him to make sure as she moves away.
0:27:05 > 0:27:08That worked really nicely for her, because he then sits down,
0:27:08 > 0:27:12she goes away, game over - and then she can get on with her day
0:27:12 > 0:27:15without getting beaten up or anything nasty happening to her.
0:27:17 > 0:27:20'Having analysed hundreds of hours of footage,
0:27:20 > 0:27:23'Cat knows that even the most innocent of gestures
0:27:23 > 0:27:25'can conceal an ulterior motive.'
0:27:27 > 0:27:28What we've got here
0:27:28 > 0:27:33is one of the big, dominant males and another female, and he actually wants
0:27:33 > 0:27:37to groom her, because he would really like for her to come away with him.
0:27:38 > 0:27:42What he does is give some beautiful, big, loud scratches,
0:27:42 > 0:27:45and they're really obvious gestures, but she doesn't do anything
0:27:45 > 0:27:49at that point, so what we then see is that he persists.
0:27:51 > 0:27:54He mixes some other gestures in there, he gives a bit of an object
0:27:54 > 0:27:58shake, and the big scratching tends to be an invitation for grooming,
0:27:58 > 0:28:01and the object shake is about, "move yourself".
0:28:01 > 0:28:03So, he's basically saying, "Come over here,
0:28:03 > 0:28:04"I would quite like to groom you."
0:28:06 > 0:28:08And she's sort of thinking about it.
0:28:12 > 0:28:16And then what you see is that she then comes down the tree,
0:28:16 > 0:28:20and approaches over to him, and they have a lovely little groom
0:28:20 > 0:28:21for a while.
0:28:22 > 0:28:25And actually this worked out really well for him,
0:28:25 > 0:28:27because about half an hour later they disappeared off
0:28:27 > 0:28:30and weren't seen for a couple of weeks, and came back,
0:28:30 > 0:28:32and we're trying to work out if she's now pregnant.
0:28:32 > 0:28:34So, fingers crossed.
0:28:34 > 0:28:36'So far, Cat has doubled the number
0:28:36 > 0:28:41'of previously recorded chimp gestures, confirming 66 to date.
0:28:42 > 0:28:46'Thanks to her work, we now have a chimp dictionary.'
0:28:48 > 0:28:50"Can you move over there, please?"
0:28:52 > 0:28:54"I'd like you to groom me, please."
0:29:00 > 0:29:01"Climb aboard."
0:29:06 > 0:29:07"Can you feed me, please?"
0:29:12 > 0:29:14"Sorry, let's make up."
0:29:18 > 0:29:19Just as with humans,
0:29:19 > 0:29:22over half of all chimp communication is non-vocal.
0:29:24 > 0:29:27And around a third of the gestures recorded so far
0:29:27 > 0:29:29are similar to ones we use.
0:29:33 > 0:29:38They're seen in all chimps, and are part of what make these apes great.
0:29:41 > 0:29:44'Cat's painstaking research has given me
0:29:44 > 0:29:47'a rare, intimate glimpse of family life.
0:29:47 > 0:29:52'What I've seen is that chimps constantly communicate
0:29:52 > 0:29:53'using body language.'
0:29:54 > 0:29:59A simple scratch, grunt or wave can actually be laden with meaning.
0:30:01 > 0:30:05The other thing that's struck me is how similar a lot of chimp gestures
0:30:05 > 0:30:09are to our own, especially with their nearest and dearest.
0:30:11 > 0:30:14'So far, I've seen the key role that communication plays
0:30:14 > 0:30:16'in different groups of animals.
0:30:16 > 0:30:21'But what I want to see now is how they communicate one on one.
0:30:21 > 0:30:24'Because, with the very survival of the species dependant
0:30:24 > 0:30:28'on finding a mate, some creatures have extremely sophisticated
0:30:28 > 0:30:31'methods of attracting the opposite sex.
0:30:34 > 0:30:35'To find out more,
0:30:35 > 0:30:39'I've travelled 7,000 miles to North America, swapping Africa
0:30:39 > 0:30:41'for a meadow in Massachusetts.'
0:30:44 > 0:30:47I'm looking for a couple of scientists who have learned to speak
0:30:47 > 0:30:51to a strange little bug using the language of light.
0:30:53 > 0:30:57'It's midsummer - the highlight of the North American firefly's year.
0:30:59 > 0:31:03'They're about to begin an annual two-week dating frenzy.'
0:31:04 > 0:31:09- So, what is our temperature tonight so far?- 79 Fahrenheit.
0:31:09 > 0:31:13'Dr Chris Cratsley and Professor Andy Moiseff are here to help me
0:31:13 > 0:31:16'unlock the secrets of their mating rituals.'
0:31:16 > 0:31:18Hello there, I'm Lucy.
0:31:18 > 0:31:20- Hi, Lucy. I'm Chris. - Chris, nice to meet you.
0:31:20 > 0:31:24- Andy.- Hi, Andy. Are you telling me we can really speak to a firefly?
0:31:24 > 0:31:27- We're going to try! - Really?! Do they chat back?- Yes.
0:31:27 > 0:31:30In the North American fireflies, there is dialogue,
0:31:30 > 0:31:35- a communication between males and females.- How do I speak to them?
0:31:35 > 0:31:38Well, we're going to do it a couple of different ways.
0:31:38 > 0:31:42We can use something as simple as a pen-light to flash as a female.
0:31:42 > 0:31:47But we also have another device here - the firefly fishing rod,
0:31:47 > 0:31:50and this will let us get a bit higher.
0:31:50 > 0:31:52It can fly around and be a male flashing,
0:31:52 > 0:31:56and look for females responding in the vegetation.
0:31:56 > 0:31:58So the light display is all about mating, basically.
0:31:58 > 0:32:00It's kind of like a firefly singles bar
0:32:00 > 0:32:03- that we're going to visit tonight. - Yes, that's right.
0:32:05 > 0:32:07Actually a type of beetle,
0:32:07 > 0:32:11most of the firefly's two-year life span is spent underground.
0:32:13 > 0:32:17After hatching, they live as adults for just two weeks.
0:32:18 > 0:32:21There are nearly 2,000 species worldwide.
0:32:21 > 0:32:25Almost all have developed their own specific flash pattern,
0:32:25 > 0:32:31and it's used for just one thing - attracting the perfect partner.
0:32:33 > 0:32:36There are at least five different species in this meadow alone,
0:32:36 > 0:32:40all broadcasting in their own unique languages.
0:32:44 > 0:32:48It's a bit like trying to speed date in an airport departure lounge.
0:32:50 > 0:32:54'Now, I want to investigate how these flirtatious flashes work.'
0:32:54 > 0:32:56I thought I saw one over there.
0:32:56 > 0:32:59Oh, I can see one there! I'm going to try and get that one.
0:32:59 > 0:33:02That's closer, you might be able to catch that one with the net.
0:33:04 > 0:33:07I'm sure... Did I do that too viciously?
0:33:07 > 0:33:09No, you can be as vicious as you want.
0:33:09 > 0:33:12But try to get the net under it, so that it falls...
0:33:12 > 0:33:16Oh, I can see... Oh, my goodness me, there he is!
0:33:16 > 0:33:21Look. I've caught my very first firefly.
0:33:22 > 0:33:24Ooh! Where'd he go?
0:33:25 > 0:33:27He's flashing down my shirt!
0:33:27 > 0:33:30This is the wrong kind of lady that you're after.
0:33:30 > 0:33:33Let's get him in the jar. Shall we get him in the jar?
0:33:33 > 0:33:38So, now it's contained, we can see that that powerful light
0:33:38 > 0:33:42is coming from a tiny lantern on the firefly's underside,
0:33:42 > 0:33:46and it can angle that lantern to point the light,
0:33:46 > 0:33:49and therefore the chat, at whoever it fancies.
0:33:49 > 0:33:53And the light itself is bioluminescence, or living light,
0:33:53 > 0:33:56and it's produced by a chemical reaction,
0:33:56 > 0:33:58and it's incredibly energy efficient.
0:34:00 > 0:34:03The firefly is one of only a handful of land animals to use
0:34:03 > 0:34:07bioluminescence. But underwater...
0:34:07 > 0:34:10it's a very different story.
0:34:12 > 0:34:1490% of deep sea marine life
0:34:14 > 0:34:16is thought to produce bioluminescence...
0:34:19 > 0:34:22..using it to light their way, locate friends,
0:34:22 > 0:34:25or, like the firefly, to speak to potential mates.
0:34:25 > 0:34:29The darkest depths of the world's oceans are the backdrop
0:34:29 > 0:34:32for one of nature's most impressive lightshows.
0:34:34 > 0:34:35Back on land, I want to see
0:34:35 > 0:34:39if I can get to grips with this luminous seduction technique.
0:34:39 > 0:34:42We're going to have to switch now to special low-light cameras,
0:34:42 > 0:34:46because our lights are disturbing the fireflies
0:34:46 > 0:34:48and putting them off their chat.
0:34:49 > 0:34:51What are we looking at here?
0:34:51 > 0:34:54Pretty much everything you see are males. Because the males
0:34:54 > 0:34:56will come out first, and at this point in the season
0:34:56 > 0:34:59- there are many more of them than there are females.- Ah!
0:34:59 > 0:35:01- The kind of ratio I like. - HE LAUGHS
0:35:01 > 0:35:07And so they will be out advertising, cruising looking for females.
0:35:07 > 0:35:10They'll flash and then they'll look for a response from the females
0:35:10 > 0:35:12somewhere below them in the vegetation.
0:35:12 > 0:35:16Males and females have different flash rates. But thankfully,
0:35:16 > 0:35:19Chris speaks all forms of firefly, fluently.
0:35:19 > 0:35:22What I want you to try and be is a male firefly
0:35:22 > 0:35:25that flashes every eight seconds or so.
0:35:25 > 0:35:29'My first date is with a female Photinus Ignites.
0:35:30 > 0:35:33'I'm using Chris' LED fishing rod to
0:35:33 > 0:35:36'try and chat one up by mimicking a male.'
0:35:36 > 0:35:40You've got some competition out here because there's other male fireflies
0:35:40 > 0:35:43around that are going to be trying to flash to these females as well.
0:35:43 > 0:35:48'Most females can't fly, instead focusing all their energy
0:35:48 > 0:35:49'on egg production,
0:35:49 > 0:35:53'leaving the males, like me, to do all the chasing.'
0:35:53 > 0:35:56Oh, I got her interested. How long do I wait? Tell me when.
0:35:56 > 0:35:58- Tell me when.- Go ahead.
0:35:59 > 0:36:01Yeah. Hello.
0:36:03 > 0:36:05She responded to someone else
0:36:05 > 0:36:08and he very quickly produced another flash right after her response.
0:36:08 > 0:36:12- He's much better at it than I am. - That's him again.- Oh, that's him.
0:36:12 > 0:36:14- He's getting really close to her. - Yeah, he's competing with you.
0:36:14 > 0:36:16There she's responded to him.
0:36:16 > 0:36:20- They're getting really close to each other.- We still do have another
0:36:20 > 0:36:23- female over here.- OK, I'm going to give her a flash.- There she is.
0:36:23 > 0:36:25- OK, now don't go too close to her. - OK.
0:36:27 > 0:36:29She's being very picky, isn't she?
0:36:29 > 0:36:31She's being very picky. Is it my technique?
0:36:31 > 0:36:35Your struggles are not that unusual as a male firefly.
0:36:35 > 0:36:37I feel the pain of the male firefly.
0:36:37 > 0:36:41This has given me a window into their world
0:36:41 > 0:36:45and they're very finicky these girls, they're hard to please.
0:36:45 > 0:36:47I've been rejected.
0:36:48 > 0:36:54Female fireflies are real flirts, often chatting up 10 males at a time
0:36:54 > 0:36:57before finally committing to Mr Right.
0:36:57 > 0:37:00But having failed to attract any interest, I'm going
0:37:00 > 0:37:02to swap teams, and try my luck with the boys.
0:37:04 > 0:37:08For this particular species, if we want to mimic a female,
0:37:08 > 0:37:12we should flash four seconds after we see a male flash
0:37:12 > 0:37:14and so let's see if we...
0:37:14 > 0:37:19Here's one that flashed right here. Let's see if we can mimic a female.
0:37:19 > 0:37:23Now the female flashes are a little bit longer in duration than
0:37:23 > 0:37:25the male flashes and of course,
0:37:25 > 0:37:27if we're using a pen-light like this, we have to muffle
0:37:27 > 0:37:30it down in the vegetation because that's where the females will be.
0:37:30 > 0:37:33- Ready to try to talk to the fireflies?- I'm ready to give it a go.
0:37:33 > 0:37:36- Now what do I do? - So watch for a male flash.
0:37:36 > 0:37:38- Try flashing about three seconds after it's flashed.- OK.
0:37:41 > 0:37:42Come on, baby.
0:37:44 > 0:37:48- Pick me.- That's a good sign when it keeps flashing back.- Come on over!
0:37:49 > 0:37:53- Hello! - And you know they can't hear you.
0:37:56 > 0:37:59I'm actually having a conversation with a firefly.
0:37:59 > 0:38:03In fact, I'm not just having a conversation, I'm chatting it up.
0:38:07 > 0:38:10Flash. Yeah, flash back, I'm interested.
0:38:14 > 0:38:17This is extremely awkward
0:38:17 > 0:38:21but the male firefly that I was just chatting up is now being eaten
0:38:21 > 0:38:26by a spider so it's an abrupt end to our conversation.
0:38:29 > 0:38:31I can't watch. It's too sad.
0:38:33 > 0:38:36After two fireflies do manage to mate,
0:38:36 > 0:38:39they'll go their separate ways.
0:38:39 > 0:38:41Over the course of the next two weeks, their lanterns will
0:38:41 > 0:38:46steadily dim. Until finally, their light goes out for good.
0:38:48 > 0:38:52It's been a bit of a revelation to discover that you can actually
0:38:52 > 0:38:53speak to a firefly quite easily.
0:38:53 > 0:38:57All you really need is a pen-light and quite a bit of patience and
0:38:57 > 0:39:02you have to know the specific Morse code of the firefly and you're away.
0:39:02 > 0:39:04You're having a chat with an animal.
0:39:08 > 0:39:10But not all animals are
0:39:10 > 0:39:12so rigid in their dating rituals.
0:39:13 > 0:39:15I've come to meet the red deer,
0:39:15 > 0:39:18who take a more flexible approach to flirting
0:39:18 > 0:39:21and rather than some far flung exotic location,
0:39:21 > 0:39:26the best place to see their behaviour is just outside Bristol.
0:39:27 > 0:39:30The females here at Ashton Court are spoiled for choice
0:39:30 > 0:39:33because there's about 10 males in these grounds
0:39:33 > 0:39:36and now it's the start of the rutting season
0:39:36 > 0:39:40and the stags begin these ritualised displays of dominance
0:39:40 > 0:39:44in order for them to take control of the ladies. But the ladies
0:39:44 > 0:39:49are choosing the stags as much based on how they sound as how they look.
0:39:52 > 0:39:55Male and female deer live separately most of the time,
0:39:55 > 0:40:00only coming together for the annual two month rutting season.
0:40:01 > 0:40:05The males then battle it out to win exclusive rights
0:40:05 > 0:40:07to a whole harem of females.
0:40:07 > 0:40:11Red Deer Stags are impressive animals on the outside
0:40:11 > 0:40:15and on the inside they've evolved a special physiology
0:40:15 > 0:40:18that allows them to turn on the charm.
0:40:18 > 0:40:20STAG ROARS
0:40:22 > 0:40:26'Dr David Reby is a pioneer in the study of vocal communication.'
0:40:26 > 0:40:28ROARING CONTINUES
0:40:28 > 0:40:32'By analysing and artificially adjusting their calls,
0:40:32 > 0:40:35'he's found out what makes a stag irresistible.'
0:40:35 > 0:40:37So, David,
0:40:37 > 0:40:40in your studies, you manipulate the stags voices to make them sexier?
0:40:40 > 0:40:42- Yes.- Can you do the same thing with my voice?
0:40:42 > 0:40:46Yes. What I'm going to do is record your voice. OK.
0:40:46 > 0:40:48This is Lucy. Turn me into a sexy stag.
0:40:50 > 0:40:52- Shall we play this? - Yes, please.
0:40:52 > 0:40:56DEEP VOICE: This is Lucy. Turn me into a sexy stag.
0:40:56 > 0:41:00God! I really do sound like a man, that's so weird.
0:41:00 > 0:41:04'What David's done is lowered the resonance of my voice.
0:41:04 > 0:41:09'The acoustical quality, created by reverberations in the throat.
0:41:09 > 0:41:11STAG ROARS
0:41:11 > 0:41:13Lady deer like a roar with lower resonance,
0:41:13 > 0:41:18because it should mean a bigger stag and therefore stronger offspring.
0:41:19 > 0:41:22'To find out how important the right roar can be,
0:41:22 > 0:41:25'David and I are going to conduct an experiment.
0:41:25 > 0:41:29'First we're going to play the call of a young adult male.'
0:41:29 > 0:41:30RECORDING OF A ROAR PLAYS
0:41:33 > 0:41:36There's little response from the resident stag.
0:41:42 > 0:41:44And his harem are even less impressed.
0:41:46 > 0:41:48You've just played the roar of a stag
0:41:48 > 0:41:50that's probably smaller than him.
0:41:50 > 0:41:54So he doesn't need to put a lot of effort into his response.
0:41:54 > 0:41:57Certainly I don't expect him to leave his harem and come over here.
0:41:59 > 0:42:02'So how can a young buck ever hope to win over
0:42:02 > 0:42:06'these hard-to-please ladies? David thinks they've developed
0:42:06 > 0:42:09'a trick to lower the resonance of their roars.'
0:42:09 > 0:42:12What they do is they lower their larynx further.
0:42:12 > 0:42:15The larynx is the voice-box which is the equivalent
0:42:15 > 0:42:18of my Adam's apple here and, when they roar, they also have
0:42:18 > 0:42:22the ability of lowering the larynx all the way down to the sternum.
0:42:22 > 0:42:25- So they sound bigger...- Yes. - ..which is cheating basically.
0:42:25 > 0:42:27Absolutely.
0:42:27 > 0:42:29I would say they give an exaggerated impression of their body size.
0:42:29 > 0:42:32They sound bigger than a deer should but they all do it.
0:42:34 > 0:42:37By pulling down the larynx, deer can increase
0:42:37 > 0:42:41the length of their vocal tract, making them sound up to 40% larger.
0:42:43 > 0:42:46And to see just how effective this can be,
0:42:46 > 0:42:48we're bringing out the big guns.
0:42:48 > 0:42:50I'm going to play a roar
0:42:50 > 0:42:53where the resonances have been much lowered.
0:42:53 > 0:42:54DEEPER ROAR PLAYS
0:43:05 > 0:43:08Well, we've definitely got the girls' attention.
0:43:11 > 0:43:12STAG ROARS
0:43:14 > 0:43:16He's clearly now quite worried.
0:43:19 > 0:43:20ROARING CONTINUES
0:43:22 > 0:43:24It looks like...
0:43:24 > 0:43:28Are they leaving? Yes, they are, they're starting to leave.
0:43:36 > 0:43:38He's lost about a third of his harem now.
0:43:41 > 0:43:42You can hear his roaring,
0:43:42 > 0:43:45trying to do something about what is happening to his harem.
0:43:48 > 0:43:52'He's lost the attention of his ladies...for now.
0:43:52 > 0:43:56'With no real rival around, they will return to the resident stag.
0:43:57 > 0:44:01'But this isn't just a glimpse into the private lives of deer.
0:44:01 > 0:44:04'Because the ability to manipulate resonance
0:44:04 > 0:44:07'has long since thought to be unique to humans.'
0:44:07 > 0:44:13MUSIC: "You're The First, The Last, My Everything" - Barry White
0:44:13 > 0:44:15'Now David's work may have proved
0:44:15 > 0:44:19'that we first evolved it to impress the opposite sex.'
0:44:23 > 0:44:28Recent findings have shown that humans, just like deer,
0:44:28 > 0:44:33associate bassier voices with stronger, more virile men.
0:44:33 > 0:44:34STAG ROARS
0:44:37 > 0:44:39Deer aren't the only animal to choose their mates
0:44:39 > 0:44:41based on the sound of their voice.
0:44:47 > 0:44:49I've come to Panama in Central America...
0:44:50 > 0:44:54..to meet a fascinating little creature who can pick out
0:44:54 > 0:44:57prince charming from a forest full of frogs.
0:45:00 > 0:45:02The tungara frog breeds at night,
0:45:02 > 0:45:06in and around bodies of fresh water, so I've come to
0:45:06 > 0:45:11the Gamboa rainforest with amphibian communication expert Dr Ryan Taylor.
0:45:12 > 0:45:14The thing is, if you study frogs,
0:45:14 > 0:45:17you're not allowed to use mosquito repellent because, if you do,
0:45:17 > 0:45:21it upsets the frogs because they've got really sensitive skin.
0:45:21 > 0:45:25So we are out here in a swarm of mosquitoes
0:45:25 > 0:45:27with absolutely no protection.
0:45:27 > 0:45:31- In fact, hang on a second... I'm just going to...- Ow!
0:45:31 > 0:45:33I'm not sure if that was better or not.
0:45:35 > 0:45:38The tiny tungara is just over an inch long,
0:45:38 > 0:45:40weighs less than two grams
0:45:40 > 0:45:43and is one of the most common frogs in Central America.
0:45:43 > 0:45:48I can hear hundreds of them in this small patch of swamp alone.
0:45:48 > 0:45:51It sounds like a ray gun fight.
0:45:51 > 0:45:55While most frogs are famous for their croak, the tungara is unusual
0:45:55 > 0:45:58in that it has a two-part mating call.
0:45:58 > 0:46:01- Can you do a tungara frog? - I can.
0:46:01 > 0:46:02HE IMPERSONATES FROG
0:46:02 > 0:46:03SHE IMPERSONATES FROG
0:46:03 > 0:46:05That's so not right, is it?
0:46:05 > 0:46:08The name tungara is onomatopoeia for the sound that they make,
0:46:08 > 0:46:13- so tun-ga-ra.- Tun-ga-ra. That makes sense. Tun-ga-ra.
0:46:15 > 0:46:19Male tungaras outnumber the ladies by ten to one.
0:46:19 > 0:46:22And whilst they may all sound the same to us, to a female tungara,
0:46:22 > 0:46:26the perfect call is an important factor in finding the right mate.
0:46:27 > 0:46:30But in this cacophony of calls, how can she match
0:46:30 > 0:46:34the croak that catches her attention to the right frog?
0:46:34 > 0:46:35The males are calling.
0:46:35 > 0:46:38You can actually see that vocal sac expanding whilst he's calling.
0:46:38 > 0:46:41Females seem to integrate both the calls
0:46:41 > 0:46:45and the movement of that vocal sac into assessing potential mates.
0:46:46 > 0:46:49So in order to work out who's saying what,
0:46:49 > 0:46:53the females might be lip reading or vocal sac reading to be precise.
0:46:56 > 0:46:57To put this theory to the test,
0:46:57 > 0:47:00we need a lady volunteer to take back to the lab.
0:47:02 > 0:47:06Oh, got it. Ryan's promised to bring her home afterwards.
0:47:08 > 0:47:10Now all we need is a male,
0:47:10 > 0:47:13and, back at the lab, I think I've found one.
0:47:14 > 0:47:19'Dr Barrett Klein is the only scientist in the world
0:47:19 > 0:47:24'to specialise in made-to-measure robot frogs.' Why a robot?
0:47:25 > 0:47:30Excellent question. Why not just rely on their real-life counterparts?
0:47:30 > 0:47:34So if we depend on males, real males,
0:47:34 > 0:47:38in studying how they communicate with females, we're very limited.
0:47:38 > 0:47:41If we make a robot, we can do the impossible.
0:47:41 > 0:47:43So by building a fake frog,
0:47:43 > 0:47:46- we can get to the truth of their communication.- Exactly.
0:47:46 > 0:47:49Do you think you're an obsessive, Barratt?
0:47:49 > 0:47:53Well, I think when it comes to building robofrogs, it might pay
0:47:53 > 0:47:57to be pernickety to effectively fool a female with a doppelganger.
0:47:59 > 0:48:00Model made.
0:48:00 > 0:48:03Time to find out if the females are locating the male
0:48:03 > 0:48:07whose call they like by matching it to the movement of the vocal sac.
0:48:08 > 0:48:13As tungaras are nocturnal, we place our female in a dimly lit room,
0:48:13 > 0:48:15between two speakers.
0:48:15 > 0:48:17Both will play the same male call,
0:48:17 > 0:48:20but stationed in front of one of them will be our model.
0:48:20 > 0:48:24If Ryan's right, the sight and sound of robofrog
0:48:24 > 0:48:27should prove irresistible.
0:48:27 > 0:48:31So she's sitting in there thinking, "Oh, I can hear gentlemen."
0:48:31 > 0:48:37- Indeed.- She's heading towards the speaker quite fast.
0:48:37 > 0:48:38Oh, no!
0:48:38 > 0:48:41She's... No, she's going the other way,
0:48:41 > 0:48:46she's heading towards robofrog. Come on, girl!
0:48:46 > 0:48:50You can see him singing sweet songs of love. Go to him.
0:48:54 > 0:48:56That's a decision, isn't it?
0:48:56 > 0:49:00So she was able to locate the sound that she liked with
0:49:00 > 0:49:03the visual that she liked and put the two together.
0:49:03 > 0:49:09- Yes. Absolutely.- Was it good for you, Ryan?- More than you can imagine...
0:49:09 > 0:49:12'It may seem obvious that the female would automatically assume
0:49:12 > 0:49:16'the call was coming from the only frog in the room but Ryan is
0:49:16 > 0:49:21'sure that it's all down to sac and sound being in perfect sync.
0:49:21 > 0:49:24'To see if he's right, we're going to try the experiment again,
0:49:24 > 0:49:28'but this time, robofrog's sac will be well out of whack.'
0:49:29 > 0:49:32We've altered the timing of the vocal sac artificially,
0:49:32 > 0:49:35so that it doesn't match the timing of the call.
0:49:35 > 0:49:36- Shall we go for it?- Sure.
0:49:45 > 0:49:48She turned towards the speaker. Shocking behaviour!
0:49:54 > 0:49:56I can't believe that she's going to choose the speaker.
0:49:57 > 0:49:59Oh, no, hang on, she's changing her mind,
0:49:59 > 0:50:01she's going towards robofrog now.
0:50:04 > 0:50:09That was close, she came very close to robofrog then, very close,
0:50:09 > 0:50:11but she's heading towards the speaker now.
0:50:14 > 0:50:15She gave it a bump.
0:50:15 > 0:50:18She gave the speaker a bump. We would call that a choice.
0:50:18 > 0:50:22'Our lady knows that robofrog can't be the one making the noise.
0:50:22 > 0:50:24'So she's searching the area
0:50:24 > 0:50:27'for the real source of this sexy call.'
0:50:27 > 0:50:30What the female is telling us is that it's really important
0:50:30 > 0:50:33that the timing of the vocal sac matches the timing of the call.
0:50:33 > 0:50:37- So it's a really strong cue, that visual cue.- It is.
0:50:37 > 0:50:40Like humans at a cocktail party, when you're trying to have
0:50:40 > 0:50:44a conversation and there's all this background noise, by reading lips
0:50:44 > 0:50:47it improves our speech comprehension and we think that the females
0:50:47 > 0:50:50- may be doing something similar.- She keeps going back to that speaker.
0:50:50 > 0:50:52She's been back to that speaker about five times now.
0:50:52 > 0:50:56That's unrequited love like I have never seen before.
0:50:58 > 0:51:02This sophisticated system has evolved specifically
0:51:02 > 0:51:04to help the tungaras find the right mate.
0:51:04 > 0:51:09But what it's shown me, is that animals, just like humans,
0:51:09 > 0:51:13combine information from different senses in order to communicate.
0:51:14 > 0:51:18The first leg of my journey is almost at an end.
0:51:18 > 0:51:21'There's just one thing I need to see.
0:51:22 > 0:51:25'I've travelled 3,000 miles to Berkeley, California.
0:51:25 > 0:51:26'To meet a tiny creature,
0:51:26 > 0:51:30'who's had a huge impact on the study of animal communication.
0:51:30 > 0:51:33'And Professor Damian Elias is going to introduce me.'
0:51:35 > 0:51:38So you realise, Damian, that I've never seen a jumping spider before.
0:51:38 > 0:51:40So this is the first time I've seen one.
0:51:40 > 0:51:45So jumping spiders are absolutely spectacular but they're very small.
0:51:45 > 0:51:47- Let me show you a male. - Is it OK for me to...?
0:51:51 > 0:51:52They're very cute, aren't they?
0:51:52 > 0:51:54I like thinking that if they were the size of birds
0:51:54 > 0:51:56they would be even more popular than birds.
0:51:56 > 0:51:58They're just so beautiful and so wonderful.
0:51:58 > 0:52:03I'm looking forward to seeing them under the microscope and getting a better look.
0:52:13 > 0:52:16There, that's brilliant. OK, now you can see him.
0:52:16 > 0:52:19'There are 5,000 species of jumping spider worldwide.
0:52:21 > 0:52:23'They all have different characteristics,
0:52:23 > 0:52:25'but one thing they have in common
0:52:25 > 0:52:29'is the ability to perform elaborate courtship dances.
0:52:30 > 0:52:33'Damian wants to show me the jumping spider's moves,
0:52:33 > 0:52:36'but first, we need a dance floor.'
0:52:36 > 0:52:39Damian, why have you just handed me a pair of ladies tights?
0:52:39 > 0:52:42Well, surprisingly, one of the best surfaces
0:52:42 > 0:52:46we found for males to dance on, one of the best dance-floors is actually
0:52:46 > 0:52:50- a pair of ladies tights.- Where did these tights come from, Damian?
0:52:50 > 0:52:53These tights came from my girlfriend's mother.
0:52:55 > 0:52:58Surreptitiously at one point.
0:53:06 > 0:53:08Here you go.
0:53:08 > 0:53:11We have one spider disco dance floor.
0:53:12 > 0:53:15'Next we need a dance partner.
0:53:15 > 0:53:19'And luckily, Damian has a freezer full of dead females.'
0:53:19 > 0:53:22We call this our graveyard of females.
0:53:22 > 0:53:26- Aw! There's some good specimens in here.- Yeah.
0:53:27 > 0:53:28That is fantastic.
0:53:29 > 0:53:33One female puppet ready to flirt with a male.
0:53:36 > 0:53:38'First we have to attach her to the dance floor,
0:53:38 > 0:53:42'and Damien's going to let me be the puppet master.'
0:53:42 > 0:53:46Now, as you turn the dial, you can see that the female turns with it.
0:53:46 > 0:53:49I'm going to have to learn how to move like a female spider
0:53:49 > 0:53:51if I'm going to get that male to dance for me, basically.
0:53:51 > 0:53:52How do I do that?
0:53:52 > 0:53:56You want the puppet to show a lot of interest to lock her gaze at the male
0:53:56 > 0:54:00and just track exactly the directions of where he's going.
0:54:00 > 0:54:03- So it's all in the eyes. - It's all in the eyes.- Really?
0:54:09 > 0:54:11Right there, stop for a little bit.
0:54:11 > 0:54:14I'm locking eyes with him. He's waving his hands at me!
0:54:16 > 0:54:21It is a very nervous movement, isn't it? That kind of dodging around.
0:54:21 > 0:54:25Females are much larger than the males and so cannibalism
0:54:25 > 0:54:29is actually quite a common occurrence in jumping spiders.
0:54:29 > 0:54:33So the pressure's on for Mr Spider. In the wild,
0:54:33 > 0:54:36if he put a foot wrong, she'd make a meal out of him.
0:54:45 > 0:54:47I like you.
0:54:47 > 0:54:48I surrender to your beauty.
0:54:51 > 0:54:54The fancy footwork seems to be getting him nowhere.
0:54:54 > 0:54:59But there's more to this dance than meets the eye.
0:55:00 > 0:55:03RUMBLING
0:55:03 > 0:55:05That's incredible, that noise.
0:55:05 > 0:55:08He's making that noise to attract her, is he?
0:55:08 > 0:55:12- Yes, he is.- This sound is created by the spider's abdomen
0:55:12 > 0:55:15vibrating against the dance floor.
0:55:15 > 0:55:16RUMBLING CONTINUES
0:55:17 > 0:55:21'Using a powerful microphone, we're able to reveal
0:55:21 > 0:55:23'the most critical aspect of this display.
0:55:25 > 0:55:27'The performance is over.
0:55:28 > 0:55:30'Time for the male to make his move.
0:55:31 > 0:55:34'But for this poor fellow, it's the brush off.'
0:55:35 > 0:55:40That was extraordinary. It was like having a bumble bee trapped inside
0:55:40 > 0:55:44- a jar.- Most things that are small use this type of communication and
0:55:44 > 0:55:48it's basically been completely hidden to us until technology came along.
0:55:48 > 0:55:51The scales fall from your eyes and all of a sudden you see
0:55:51 > 0:55:54all of these things that you never, never knew existed
0:55:54 > 0:55:56or scientists never ever expected.
0:55:59 > 0:56:03That was incredibly exciting. I've just had a spider
0:56:03 > 0:56:06not only dance for me, but sing his heart out
0:56:06 > 0:56:11in the most extraordinary manner in a secret seismic language.
0:56:14 > 0:56:16The jumping spider isn't the only creature
0:56:16 > 0:56:18to use seismic communication.
0:56:21 > 0:56:23Elephants can detect vibrations through
0:56:23 > 0:56:28the skin on their massive feet from an astonishing 16 kilometres away.
0:56:29 > 0:56:32But what our friend the spider shows
0:56:32 > 0:56:35is that tiny creatures like insects and arachnids
0:56:35 > 0:56:38have found a way to make their presence felt.
0:56:39 > 0:56:43Leaf cutter ants send vibrations through plants to recruit
0:56:43 > 0:56:47other colony members. Termites use them to raise the alarm
0:56:47 > 0:56:48when predators are spotted.
0:56:50 > 0:56:52In fact, it's estimated that
0:56:52 > 0:56:56more than 90% of insects use seismic signals.
0:56:58 > 0:57:00Their messages may only make it a few metres,
0:57:00 > 0:57:06but for creatures this small, that's communicating on a grand scale.
0:57:07 > 0:57:11I started out on this epic journey wanting to fulfil a childhood dream
0:57:11 > 0:57:17of talking to the animals and I've totally succeeded...
0:57:17 > 0:57:21thanks to the help of some slightly nutty professors.
0:57:21 > 0:57:25But their ingenuity and dedication have given me access
0:57:25 > 0:57:28to secret worlds filled with noises we can't hear,
0:57:28 > 0:57:35vibrations we can't feel and taught me languages I never knew existed.
0:57:37 > 0:57:40It's the sheer inventiveness of animal communication
0:57:40 > 0:57:43that has impressed me most. The way that it's evolved
0:57:43 > 0:57:47to overcome extraordinary hurdles to ensure that, like us,
0:57:47 > 0:57:50animals find and keep in touch with the ones they love.
0:57:53 > 0:57:55'Next time, I'll discover
0:57:55 > 0:57:59'just how sophisticated animal-speak really is.'
0:57:59 > 0:58:01Oh, my word! They're coming towards us.
0:58:01 > 0:58:03'And find out exactly what they're saying...'
0:58:03 > 0:58:06They're definitely, definitely telling me to leave.
0:58:06 > 0:58:07'..to enemies...'
0:58:07 > 0:58:11It's the first example of infra red communication in animals.
0:58:11 > 0:58:15'..friends...' This is amazing. So this is a dolphin greeting.
0:58:15 > 0:58:17'..and even their neighbours.'
0:58:17 > 0:58:20The second they heard that, they dashed to cover.
0:58:20 > 0:58:23So we've just seen a meerkat neighbourhood watch scheme.