In the natural world...
..you need to be smart...
..to stay alive.
But we're only just discovering that some animals are brighter...
..than we ever imagined.
I never fail to be impressed by nature's sheer ingenuity.
Now, brand-new science, using innovative techniques
and the latest technology,
is revealing some surprising brainboxes.
You can get bees to learn almost anything.
Researchers across the globe...
THEY LAUGH
..are uncovering the mind-blowing tricks...
..and clever strategies that give certain species the upper hand.
It is an animal showcasing its intelligence
in front of your eyes.
As they build their homes...
..navigate their world...
..and raise their young.
It's time to get inside the minds of nature's savviest species.
But I warn you, there's going to be a few surprises
and some controversial candidates.
But, most importantly, it's going to give us an opportunity
to learn from these animal Einsteins.
And that's really exciting.
We humans may think we're good at getting our message across,
but the animal kingdom has some seriously clever communicators.
CHIRPING
In this episode, I'll see a breakthrough in chimp chat.
What we found just blew our minds.
Feel the buzz of a new honey bee dictionary.
It's, "Quack! Quack! Quack! Quack!"
And learn a special shrimp's secret messages.
A covert communication shrimp.
ROARING
TRUMPETING
CHIRPING
SNIFFING
When we take a walk in the wilder environment outside,
we tend to forget there's a whole world of communication here
that we can neither access, nor fully understand.
Listen.
Above the sound of the wind in the trees there,
you can hear birds calling.
And, of course, when we hear them singing,
we love that exquisite cascade of notes.
That beautiful sound.
BIRDSONG
And look at the dogs, their noses are constantly twitching.
Theirs is not so much a visual world as a world of smell.
SNIFFING
If we could hear, smell, see and feel
all of the communication going on around us,
we would be utterly overwhelmed.
And that, just in this little corner of the English countryside.
The animal world is jam-packed with clever communicators.
SQUEALING
ROARING
CALLING
BARKING
CROAKING
BUZZING
CACKLING
SQUAWK!
BIRDSONG
It's long been a quest for scientists
to try and cut through this complicated world of communication.
To get beyond our basic understanding
and reveal what animals are actually saying.
WHINING
I mean, if we could talk to the animals,
if we could learn their languages,
just think of all the things we could discuss.
What did you say when you were leaving? Say goodbye.
In an attempt to play Dr Dolittle,
scientists have turned to our closest animal relative,
the chimpanzee.
We've been trying to chat with chimps for decades,
but despite sharing around 99% of their DNA,
our attempts to teach them human language have largely failed.
First words...
CHIMP VOCALISES
..then sign language.
Not only were some of the experiments questionable
in terms of the chimps' welfare,
the whole concept of teaching them was flawed.
Instead, we needed to learn from the chimps,
by studying them in their natural habitat.
Now, following years of meticulous observations in the field,
scientists are beginning to break through the ape language barrier.
We've got a little family going down one of the forest trails here,
and it's Jenny, James
and her older daughter, Janet, following on behind.
And James is quite young at this point and Mum wants to get going,
so she pauses and just lifts and wiggles her back foot at him.
That's the signal that he has to climb on board
so that they can travel off for the day.
Primatologist Dr Cat Hobaiter from the University of St Andrews
has spent more than 15 years
at the cutting edge of chimp communication research.
My main aim is basically to follow them around with my camera
and try and capture as much as possible
of their day-to-day communication.
Chimpanzees communicate in all of the ways we do.
Everything from vocalisations to body postures,
to facial expressions and, then,
to this incredible repertoire of gestures that they have.
Fundamentally, the vocalisations tend to be about the high drama.
The big kind of alarm, danger, predator.
HOOTING
With gesture, it's like getting to tune into their gossip channel.
All of these little different gestures that they make,
and they have over probably 70 different kinds,
are the ways in which they...they just go about their day-to-day life.
It's the, "Come here", or, "Can you give me that?"
or, "Go away, get lost".
What we've got here is Behati and Brian.
Now, Brian is a little boy
and he's getting to be that kind of juvenile stage
when he wants to join in with the big pant-hoot chorus
that all the adults love giving.
But that's still a kind of intimidating thing for him to do sometimes.
The pant-hoot is an important skill
for a young chimp like Brian to learn.
It plays a vital part in bonding the group together,
no matter where they are in the forest.
When he starts to pant-hoot, he reaches back
and he pops his fingers in his mum's mouth
and she pops her fingers in his mouth.
And that just seems to reassure him a little bit
that it was OK for him to do that.
Of the five great apes -
the gorilla, orangutan, chimpanzee, bonobo and us,
the closest cousins in evolutionary terms are the chimp and bonobo,
separated by a mere one million years.
Cat found that a fellow scientist, Dr Kirsty Graham,
had been conducting her own research on bonobos
in the Democratic Republic of the Congo,
700 miles away from Cat's Ugandan chimps.
They may look fairly similar,
but these are two very different species.
And when Cat and Kirsty combined their results,
they had a breakthrough.
One of the things Kirsty and I found when we put our data together,
when we put our studies together, was that
of the 60 or 70 gestures that we defined in the chimps,
almost all of them are present in bonobos.
And, actually, the more data we get on bonobos, the more overlap we see.
It blew our minds.
We expected some overlap, but just to see...
I mean, we're talking at the moment about 95%
between the types of gestures that they're using
and very high overlap in terms of the meanings.
We never would have expected to see anything quite like that.
These fundamental similarities in the use of gesture
must be rooted in the chimp and bonobos' evolution
from a common ancestor.
Incredibly, it means if a bonobo and a chimp came face-to-face,
they could probably communicate with each other cross-species.
And if chimps and bonobos share gestures,
what of the other great apes?
Sure enough, when Cat and her fellow biologists combined their research,
they were able to create a dictionary of distinct ape gestures
across four of the five great apes.
Leaving just one ape to test - us.
The team created this online quiz.
It gives a random selection of ape gestures,
but will I know what they all mean?
OK, so the animal on the right
is stroking the chin of the animal on the left, which is eating.
It's not "Stop doing that", clearly,
nor, "Move closer to me".
This is "Give me that food".
I'm pretty confident of that.
OK, two chimpanzees on the ground.
Well, hats off to the scientists.
Some of these gestures are very subtle,
and it's hard to know if I'm getting them right.
But, as in any statistical test,
there is a baseline for measuring success.
In order to show that people could understand what these ape
gestures mean, we needed them to be performing better than chance.
And chance was one in four - 25%.
And it turns out that people can do it really quite easily.
OK, I think that's it.
Let's see.
Well!
I scored 13 out of 20.
That's 65% correct.
I certainly did better than blind luck would dictate,
and I'm not alone.
The study showed that the majority of people can correctly decipher
some ape gestures, with a few of the gestures understood 80% of the time.
We made it as hard as we possibly could.
We give no information,
and yet people can still understand what these gestures mean
just from seeing these few seconds of movement.
To be honest, there was a tiny part of us that was a little bit annoyed
at that! Because we literally... literally we have spent our academic
lives devoted to trying to understand it,
and it turns out that you can do it instinctively
really quite accurately!
So, amazingly, we humans seem to have an innate understanding
of ape gestures and how to interpret them.
It's a Dr Dolittle skill that most of us didn't know we had.
There are some ape gestures that seem very familiar
to those that we also use.
That's what children do. When children want to be carried,
they just stand there with a grievous look on their faces,
whining, holding their hands up, like that.
So are we all making ape gestures without realising, too?
To test the theory,
the ideal subjects are small human apes.
With limited verbal communication skills,
they're commonly known as toddlers.
This was a pilot study. It was a very small group of kids.
We had children from a few different places around the world.
We picked up a camera and we followed them around for the day,
and we coded it exactly the same way
as we would have done for the chimps and the bonobos.
We expected to find a few gestures.
What we found in this pilot study just blew our minds.
We found over 50 different gestures that these kids
were using, and then, incredibly, over 45, 46 of them
are shared with the chimpanzees.
So humans use the same biologically inherited repertoire -
this repertoire of gestures that all apes share and have
in common, we have that too, and we're using it pretty prolifically
when we're still really young.
That's an incredible 90% of children's natural gestures
also used by other apes. So, on the basis of this new research,
if a bonobo, a chimp and a child met face-to-face,
they could all communicate with each other.
As we get older, our gestural communication may be superseded
by our verbal language.
But, as I proved with my test,
we still hold on to a latent ability to understand our ape cousins.
When I first started out studying gesture, I had no idea
that we were going to find just this incredible system of communication.
What's really exciting going forward is that, by truly understanding
what individual apes are saying to each other,
we get to understand their world.
We get to ask questions about how they think,
about what their intelligence is like,
about what's important to them, about their social structure.
Communication is this tool we can use
to ask a million other questions.
Cat and her colleagues' research
is truly bridging the communication gap
with our clever great ape relatives,
and providing a brand-new insight into their daily lives.
So, what does the communication of other, more birdbrained species
reveal about their intelligence?
Birdsong.
Many of us are lucky enough to hear it every day.
Of course, we know the birds are communicating with each other,
but what are they saying?
Why? And does it demonstrate intelligence?
The truth of it is, although bird songs are intricate, detailed
and beautifully tuneful, their messages are often
a little more, well, blunt.
Birds normally sing for just two reasons - to attract a mate,
or to repel the competition.
Now, we like to think of birdsong as something which is reassuringly
fixed, but every species has its individual song
which it sings in the same way, wherever it is in the world.
My favourite is the song thrush. Just listen to this.
SONG THRUSH SINGS
It's beautiful, isn't it?
Those whistles, those cascades of notes.
Really lifts your spirit in springtime.
But here's a question.
Do you think that song thrushes were singing exactly the same song
100 years ago? Well, I can't answer that.
I wasn't around 100 years ago, but there is something I can tell you,
and that is that there's one species of bird
that has very definitely changed its tune in recent times.
The white-throated sparrow is a small ground nesting bird,
widespread across the US and Canada.
The male bird was always known for this song...
It's a pretty tune with a triplet ending.
But, around 50 years ago, to the west of the Rocky Mountains
in British Columbia, a new version of the song emerged.
This one has a doublet phrase to finish.
This new, simpler-ending song must have proved popular with the females
because it spread quickly, and has now been adopted by birds
2,000 miles away in western Quebec.
So, how have these white-throated sparrows transformed their song
so quickly over such a broad geographical area?
Well, perhaps it's because the song was so simple to start with.
It's an onomatopoeic song, in that it sounds like something
that we might say. In this case, people thought they were saying,
"Oh, sweet Canada, Canada, Canada."
Only now, they're singing, "Oh, sweet Cana, Cana, Cana."
All they've done is drop a syllable to make a big difference,
and I think I can demonstrate how effectively that works
with a very simple tune here.
It's about five ducklings. It's a nursery rhyme.
And, of course, we want our nursery rhymes to be very simple
so that children can learn them,
so they have a limited range of notes and they're very repetitive.
"FIVE LITTLE DUCKS" PLAYS
Repetitive to the point of being a little bit tedious.
To my mind, this is a song that needs transformation.
So I put a safety pin through my beak.
I've been doing a bit of mixing on the decks here
and I've come up with...
..this.
DRUMS AND GUITAR ADDED
In fact, let's have a bit more volume.
Yes! I think that's altogether a great improvement of this song.
But, of course, you can still hear the original tune.
Thankfully, only just.
It goes to show a few punk amendments have a big impact,
and the white-throated sparrows' remix
must have impressed the females.
We think that has to be the reason behind his change in tune.
Now, most bird songs are learned from parent birds, either
when the chicks are still in the nest or when they've just fledged.
But some birds' home-schooling needs to begin even earlier,
all because of a punk impostor.
CUCKOOS
The cuckoo's anti-establishment behaviour is brazen
and, when it comes to hard work, it prefers to let others do the graft.
Especially parenting.
Often, cuckoos leave their eggs in the nest of another species,
leaving the unwitting parents to bring up their baby.
It's called brood parasitism.
But over in Australia, there's one small songbird that's outsmarted
the canny cuckoo...with some incredible prenatal communication.
When we walked around the park, we had heard these noises
from the nest, and we really had no idea why a female
would be being so conspicuous, because it attracts predators.
Professor Sonia Kleindorfer and Dr Diane Colombelli-Negrel
have been studying the superb fairy wren in Adelaide.
So we recorded the call for several hours.
Then we looked at it in a spectrogram on a computer
and we identified two elements - A and B.
We had no idea what was going on.
We kept the recorders at the nest and, then,
when the nestlings hatched, they produced a begging call.
And, strangely, each nest had a different begging call,
and that made no sense.
Why would the begging call of the same species
be different in each nest?
And so we looked at the begging call in the spectrogram,
and we found that it looked like the element B
of its mother's incubation call.
Sonia and Diane had discovered that each unique begging call -
the chick's request for food - contained a nest-specific code,
a password that must have been taught to the chick whilst
it was still an embryo in the egg.
We discovered that superb fairy-wren females are calling to the eggs
during the late phase of incubation,
and there's a specific element that the female is teaching her embryos
so that the embryos can then produce it as a hatchling to get some food.
Cuckoo chicks hatch earlier than the fairies, leaving them
too little time to learn the fairy mum's password.
So, once hatched, the only chicks to get the grub are the right ones.
So, with the fairy wrens, we are looking at how what you are exposed
to as an embryo and what you are learning as an embryo
can influence your survival and your success as a nestling,
but also as a fledgling and an adult.
The fairy wrens' superb coded password sends on a simple but vital
message to the next generation.
Clever. But it certainly couldn't be classed as language.
Human language has syntax, a set of rules for connecting words
together, giving us the ability
to make statements and form questions.
But that level of complexity is incredibly rare in the animal world.
"To be or not to be?"
That is the question, Pip.
No, clearly not impressed. I'll try again.
Shall I compare thee to a summer's day?
Though art more lovely and more temperate.
Pip's still not impressed, and that's not surprising
because our language is an incredibly
complex and structured means of communication,
which allows us to be infinitely creative, writing things like poetry
and fantastical stories. And did you know that, in the English language,
there are more than a million words? 170,000 in common parlance,
and you and I regularly use between 20,000 and 30,000
as we go about our everyday lives - using structured grammar to achieve
even the simplest things, like asking for a cup of tea with milk.
Oat milk. With two sugars, please.
So you see, when it comes to our language, it's incredibly complex.
In fact, in the animal kingdom, there are few other species
whose communication could actually be called a language.
One exception, however, are the prairie dogs.
Yes, like Pip here.
Their range of yips, chips and chitters is equally complex.
And, what's more, they can even be creative with it.
Come on, Pip, let's hear your version of Shakespeare.
For Pip's brothers and sisters, home is the plains of North America.
But, unfortunately for them, the plains are also home to a wealth
of prairie dog-eating predators.
And that sparks many a chittering chat within the pack.
Now, the more eagle-eyed of you will have spotted
that these are prop predators.
They were made by Professor Con Slobodchikoff, who devised a test
to see if he could understand prairie dog warning calls,
and he's learned they produce a different call for each predator
they spot. But it doesn't end there.
Remarkably, there's a huge amount of information
in these seemingly simple chirps.
These chirps contain a noun-like word,
and it also contains adjective-like words.
So we might say tall, skinny coyote, with yellow fur,
and the prairie dogs manage to put all of this into a single chirp.
REPETITIVE CHIRPING
The key is the prairie dog's careful control of
harmonics within each call.
This allows them to neatly and concisely package
a lot of information in a very short sound.
The ability to adapt their calls creatively, in the moment,
is a fundamental hallmark of language, a linguistic
process called productivity.
It may not be Shakespeare, but it's getting there.
Pip's using the medium of sound to show off his complex language skills,
but some animals use a completely different property of sound
to get their message across.
CONSTANT TONE
What is sound and how do we hear it?
Now, there's a question.
Well, sound starts off as vibrations
which travel through the air or water until it reaches our ears.
Now, in all truth, our ear doesn't hear the sound.
It's our brains' analysis of those vibrations and electrical
impulses which allow us to hear the sound that we hear.
We're very, very fortunate to have ears like this.
Without them, we would never be able to appreciate The Clash
and the Sex Pistols and The Jesus and Mary Chain.
But, of course, there are many species which don't
have structures like this.
But that's not to say that they can't be very sensitive
to vibrations.
If the honey bee was to fly amongst us here,
this honey bee would probably
not pick up my conversation,
because honey bees do not have eardrums.
We think they don't perceive sounds,
or, if they do, it's probably
a very poor reception of sound that they have.
Vibrations are probably one of the most important channels of communication for honey bees.
And it is a great way for them to communicate in the darkness
of the colony.
Dr Martin Bencsik is a world-leading bee specialist.
His team at Nottingham Trent University have developed
a revolutionary observation hive, allowing them to observe
natural honey BEE-haviour.
We can lift the observation stage into this transparent Perspex box.
Using military-grade technology, called accelerometers,
Martin has been able to record the vibrations that the bees use
to communicate with each other.
They allow us to pick up one vibrational pulse coming from one
individual honey bee.
This highly sensitive tech is not exactly
standard in an apiarist's toolkit.
It's more usually found in weapons guidance systems.
When I purchased these, I had to sign the paperwork promising
that I would not use these to build missiles.
The vibrations picked up by the accelerometer
are processed by a computer.
It's doing the same job that our brain does,
analysing and converting vibrational signals into sound.
Here you can see the speakers, on which the live signal
coming from two accelerometers in the hive are being fed.
RHYTHMIC BEEPING
What we are hearing here isn't the normal buzz of a bee.
This is bee communication.
Bees generate the signals with their wing muscles.
Vibrating them at a certain frequency produces a unique signal.
In human terms, they are producing individual words.
We are clarifying the repertoire of pulse vibrations
that honey bees use to communicate amongst each other.
What Martin's saying is that he's writing the world's
first bee dictionary.
I like that expression.
Yes, a bee dictionary. HE CHUCKLES
WHOOP
Bees live in very tight packing.
This is the only way they can sustain the 35 degrees
they need to live.
It is a crammed society and we think often they collide into each other
accidentally, causing the "whoop" that you can hear.
When we accidentally bump into each other in a tube station, we say, "Whoops."
It is you, the one being, the victim of the collision
who goes, "Whoops."
QUACK
The quacking signal.
The quack, as it says, is...it sounds like a duck quacking,
it goes quack, quack, quack, quack, quack, quack.
Queen bees are generated in vertical cells,
and we think that this queen bee is asking to come out.
TOOT
The tooting signal.
This queen bee has emerged from her cell
and she's roaming around the colony...
..broadcasting this enormous, splendid,
strong and long signal called the tooting.
SIREN-LIKE TOOT
We think that it manipulates the physiology of the worker bees
and we think the worker bees are led to keep the other queens,
which are quacking, they are kept captive by the worker bees in order
to avoid the presence of two mobile queens in the colony.
Without this signal to the nurse bees,
two queens would fight to the death,
leaving the colony in trouble.
To test his theory of the signals' meaning,
Martin vibrated an entire frame of bees
at the same frequency as the queen's toot.
TOOTING And sure enough,
the bees' reaction is clear.
They all appear to freeze.
The field of exploring vibrational communication is in its infancy.
We have only started to reveal the repertoire and the range
of different signals and how often they take place in a colony.
What surprised me the most is the sophistication of the behaviour
of an insect.
It is an animal showcasing, disclosing its intelligence
in front of your eyes.
You just have to lift the frame, watch them communicate.
It's very exciting.
These vibrational signals are perfect to convey simple messages
to thousands of individuals.
We can appreciate a colony as one intelligent whole.
It is, of course, the original hive mind.
But for an individual animal to share more complex messages,
it needs even smarter methods.
Dolphins are renowned for being intelligent communicators.
They use a broad range of clicks, pops and whistles to share messages
with each other over distances of around 12 miles.
But how do they create these sounds?
I can demonstrate that by showing you a dolphin skull.
Here are two orifices which come from the lungs and they would exit
through the blowhole, which sits above the dolphin's head,
that's its breathing apparatus.
But what's interesting is that, in between here and the blowhole,
it has a series of air sacks in front of these holes
which it can inflate and they act a bit like a balloon.
The dolphin can voluntarily blow them up...
..and then they can release air from these air sacks
to produce a sound...
HIGH-PITCHED WHISTLE
..similar to this.
HIGH-PITCHED WHISTLE
My impression isn't bad, but let's listen to the real thing.
LONG WHISTLE, FOLLOWED BY SHORT WHISTLE
This is the signature whistle of Imp.
This is Pasta.
SHORT, REPETITIVE PAIRS OF WHISTLES
So you can see just how different the signature whistles
of Pasta and Imp are.
Dr Stephanie King can identify dozens of individual
dolphin signature whistles or names.
These ones belong to two male bottlenose dolphins from Stephanie's
research study in Shark Bay, Australia.
They're not given this name, if you like, by their mum.
They're not born with it.
But, instead, research has shown that they use all the sounds
that they hear in their environment, other whistles, and then they create
something unique, something that's different.
Dolphins use these individual names to stand out,
to be easily identifiable to others.
As social animals, it's important they know who's who
and can recognise a useful ally.
Individuals work together to forage for food, and strong communication
is of great benefit when corralling a large shoal of fish.
But male dolphins also use their communication skills
when on the hunt for a mate, forming alliances with their best friends.
They're formed with their peers,
the other males that are similar age to them,
that they spend all their time with,
that they have strong friendships with, that they play with.
And, so, by the time they do reach sexual maturity,
they've already formed these alliances.
Only a small number of females come into season each year.
So you might imagine the competition to win a mate could get ugly.
But Stephanie's research shows quite the opposite.
You can see they work together in trios to find a female
and they will herd her.
So they'll restrict her movements
and they'll keep that female with them.
The three male buddies tightly follow the female,
but, to keep their herding formation and maintain their tight bond,
they use another form of dolphin communication -
touch.
Males will spend a lot of time petting each other,
rubbing their pectoral fins against each other,
a bit like grooming in primates
or holding hands in humans.
They're strengthening these bonds all the time.
"We are good friends, we are buddies.
"We need to work well together."
This synchronised swimming behaviour clearly shows how tight this bond
is between the three males,
but in 2020, Stephanie combined her video footage
with hydrophone underwater audio recordings
and discovered males maintain their bond
in another way, too.
We found that they don't just use physical behaviours,
but they also coordinate and synchronise one of their vocalisations -
the pops. So...
SHE POPS RHYTHMICALLY
DOLPHINS POP RHYTHMICALLY
They produce their pops in unison, matching each other's tempo,
starting and stopping at the same time
when they're herding these females.
So, this combination of touch and coordinated calls
is the key to their teamwork.
In humans, we know that synchronist behaviour leads to cooperation.
THEY CHANT IN UNISON
One great example is the haka.
In that dance display, you see those synchronised movements,
those coordinating chants.
It's meant to intimidate the rivals
and also to promote unity in the group.
"We are one strong team."
ALL: Ah!
The same appears to be true for dolphins.
And this male bonding is even more impressive when you think
of how rare this kind of collaboration is
in the animal kingdom.
When it does happen, it's normally only found in family groups,
not in would-be rivals.
It's a natural way of perhaps combating any competitiveness
that they have between them.
They all want to mate with the female or at least
they want to father the offspring.
And, over the course of their lifetime, they'll all get
opportunities if they stay together and work together.
So by maintaining these relationships and promoting unity
and strengthening their bonds over their lifetime,
they will sire more offspring than if they were on their own.
For male bottlenose dolphins, teamwork pays off
and it's all achieved through a constant communication of clicks,
whistles and touch.
In the gloom of the underwater world,
using non-visual communication makes sense.
Beneath the surface, light refracts through the water,
and, as you descend, light levels fall dramatically
and certain wavelengths of light, or colours, disappear altogether.
But there are animals down here that don't perceive light
in the same way as us.
They're using a whole different property of light
to get their message across.
They're using the polarisation of light.
Now, we can't typically see polarised light,
but I can demonstrate its existence.
When light bounces from the surface
of a pond like this, it's typically reflected with a lot of that light
in one plane of movement, it's very strongly polarised.
And, as a consequence of that, if I put on these very snazzy
polarising sunglasses and look at the pond,
the glare seems to disappear.
I'm not seeing the polarised light.
I'm filtering it out.
Whilst our eyes can't detect it,
many animals above and below the water surface,
particularly invertebrates, can see the polarisation of light.
So exactly what is it?
Bear with me for a short physics lesson.
Under normal lighting conditions, light photons leave their source -
often the sun - as electromagnetic light waves.
The light waves have two component parts - an electric field that moves
in one plane, coupled with a perpendicular magnetic field.
These two forces produce light waves oriented in many different angles.
When they're all mixed together in normal light,
they are unpolarised.
But, as soon as light hits a surface,
some of the waves are reflected in a certain plane
and become polarised.
As light travels into water,
it's scattered by tiny suspended particles, leading to an environment
even richer in polarisation.
It's a little complicated, I know,
but, for the creatures that can see it,
the polarisation of light becomes a secret communications channel
that we're only just tuning into.
To try and understand it, scientists have built cameras that replicate
the vision of the mantis shrimp.
This misnamed crustacean actually isn't a shrimp at all,
but a stomatopod,
a distant relative to crabs and lobsters.
A fearsome predator in the underwater world,
it's also known to have the best eyesight in the animal kingdom -
in part, thanks to its ability to see the polarisation of light.
We take these kind of cameras into places like
the Great Barrier Reef to look at what different animals
look like in their natural surroundings.
If you look at mantis shrimp species that occupy these environments,
many of them also look camouflaged in colour.
They stand out really clearly in polarisation.
Dr Martin How, from the University of Bristol,
has been studying the ecology of vision for more than a decade,
and he's revealing the advantages that animals gain by communicating
with polarised light.
Most big predatory fish are insensitive
to the polarisation of light.
You're essentially communicating something in secret to other members
of your species, a covert communication signal.
The benefits are twofold - as well as remaining undetected
by larger predators, for the few marine species that can see them,
they are vividly clear.
When you're signalling against a complex background,
you need to try and stand out.
And the way to do that in the simplest way possible
is in polarisation.
The other thing that's really cool about these polarised patterns
is that they work equally well at any depth.
So it's a really reliable communication pattern.
Today, Martin is using specialised camera technology
to look at two species in the lab.
The first - one of his regular research subjects,
the peacock mantis shrimp...
There we are, it grabbed the cockle.
..and another species that's never been seen before
through the polarised light camera, the dwarf cuttlefish.
Unlike a normal video camera that records the colours red,
green and blue, Martin's camera and computer software convert
polarised light, that's invisible to us, into false colour images
that we can understand.
So on the screen, the more colourful the part of the image,
the more polarised it is,
and the colour relates to the angle of polarisation that it's detecting.
So just how do these animals create their covert polarised signals?
So what these manta shrimp have is they've got these big antennal scales,
these big sort of display panels,
that they have on either side of their heads,
and they can angle those to different positions.
And, by changing the angle of those, they can change how conspicuous
that polarisation pattern is.
We are yet to fully understand what the signals mean,
but they are likely to be used to attract a mate or repel a rival.
These animals, that are equipped with very, very damaging hammers,
they're perfectly adapted to smashing open shell or cuticle.
They're also very good at damaging each other.
So that's doubly important that they communicate effectively.
One mistake in how you communicate could mean the difference
between life and death.
Martin's research is taking another step forward today,
as he's able to take his first polarised look
at the diminutive dwarf cuttlefish.
Now, I don't think anyone's looked at polarisation patterns
in this species before,
so this is quite an interesting discovery, I think.
They don't have any colour vision at all.
So these animals are completely colour-blind.
Instead, they've opted to go for very, very good polarisation vision.
Just under the pupil, here, of the eye,
we've got this little tiny green patch, that, for me,
is a good candidate for a polarisation communication signal.
This polarised signal may be small,
but it demonstrates the breakthroughs that are
only now possible in this field of research.
Right now, we're only scratching the surface.
We've identified a few animals that seem to have these polarised body patterns.
I think the more we look, the more we're going to uncover.
And that's one of the beauties of this new camera technology,
it's that we can really get out and see
where the communication patterns are.
I think we'll find all sorts of interesting things.
Whereas only some animals are equipped to see polarised light,
the vast majority of creatures use smell to interact with each other.
It's the most common basic form of animal communication.
Pheromones are chemical signals, often with a scent,
that, once secreted, trigger a social response.
Those incredible honeybees don't just rely on vibration
to converse, they have a language for more than 15 different
pheromone messages, too.
One alarm pheromone is the signal for the colony to defend itself.
Humans have learned to overpower this alarm scent with smoke
when beekeepers tend their hives.
And we are not the only smart mammal avoiding bee stings.
ELEPHANTS TRUMPET
Elephants, who aren't keen on having their sensitive trunks
injected with acidic bee venom,
have learned to detect the bee alarm pheromone for themselves,
meaning they can give an angry colony a wide berth.
We humans actually have a pretty good sense of smell,
but it's still lacking when compared
to the best animal sniffers out there.
In fact, many of our sensory abilities trail way behind other
animals, including our hearing.
We can hear from 20 hertz up to 20,000 hertz,
and to demonstrate that, I've got a sound-producing device here,
a speaker so we can hear the sound,
and an oscilloscope so we can look at the waveform.
Let me make some adjustments here...
..and turn up the volume.
MACHINE HUMS
Now, we can all hear that low frequency sound,
but if I decreases it...
TONE DIMINISHES
..towards that 20 hertz, the lower...
..end of the frequency range for human hearing...
TONE DISAPPEARS
..it disappears. I can just about...
I can't hear that now.
But I can demonstrate that there's still sound there,
cos, remember, sound is vibrations,
and if I drop some ping-pong balls onto the speaker,
you can see the vibrations
knocking them out.
Now, whilst we can't hear this,
elephants probably could
because they can hear down to 16 hertz.
It is what we call infrasound.
And they use this for communicating over vast open distances,
the savannahs, where they live, and also for keeping their big ears
open for oncoming thunderstorms.
Let me increase...
..the frequency. TONE RETURNS RAPIDLY
There we can hear it.
That's going to be around the 20 hertz mark
and, as I continue to increase the frequency, you can see more
and more waves appearing on the oscilloscope,
more waves in a certain amount of space and time
and, therefore, a higher frequency. EXTREMELY HIGH PITCH
And we get to here... I can just about hear that.
But then I'm 59 and we begin to lose our higher frequency hearing
from about 25-26 onwards, which is quite disappointing.
So I'm sure some of you can still hear this sound,
but I can't. It's gone.
But there are other animals communicating way beyond
the upper limits of our hearing.
Got all my gadgets out tonight, but it's early in the evening,
so there are only a few flies and one or two very small moths
in my moth trap.
But, in the UK, we have 800 species of larger moth,
and I can assure you that not a single one of them wants
to be eaten by a bat.
So how do they avoid that?
Moths have been involved in an evolutionary arms race
against those bats for no less than 50 million years.
And the moths are putting up a valiant defence.
Here's how.
Take a look at this species.
This is a type of tiger moth and it can hear the bats coming.
Pretty clever, you'd think it might just fly off,
but, no, it's got a trick up its wings.
What it does is then emit a high frequency burst of its own sound
to jam the bat's radar.
Then it can make good its escape.
And further, the most remarkable of all, in my opinion,
are those moths whose bodies are covered with sound-absorbing scales,
tiny hairs, which can absorb up to 85%
of the bat's echolocating calls.
Stealth moths, which just disappear off into the night.
But perhaps the top prize has to go to this species.
This is the male Asian corn borer moth,
and it, too, can mimic the sound of a bat echolocating -
but not to escape.
You see, when these moths hear that sound, they freeze,
and females like this one will freeze on any vegetation
where they're resting.
And the male moths, having mimicked the bat,
will then fly in and successfully copulate with them.
Now, what about that?
That is a smart moth.
It's not just bats and moths that use ultrasound
to their advantage.
The mysterious nocturnal world has just revealed another species
of smart ultrasonic communicator.
I was seeing them everywhere at night.
They have a fur that is actually matching the tree bark.
They have a gliding membrane attached to all their extremities.
They're often mistaken for other species,
like a flying squirrel or a bat.
PhD student Priscillia Miard,
from the Universiti Sains Malaysia,
has been rewriting the book on the Sunda colugo.
This adorable little creature is found all across Southeast Asia.
But before Priscillia's work,
very little was known about it.
In fact, the discovery that it uses ultrasound
has transformed our understanding of how they live.
Colugos are known to be shy and elusive.
Before we started to study them,
it was thought that they were solitary animals.
We found out that it's actually not true.
That's when we found out that they use ultrasounds.
So here we have...
Oh, one...and two colugos on the tree.
Oh, that's nice!
Priscillia has an enviable research location,
a five-star resort on the Malaysian island of Langkawi.
I study colugo in the resort, because it's really easy
to actually spot them.
Oh, hi.
I think this one has a baby.
They are used to people, so they can get really low.
So here we can see a colugo just hanging on the branch.
She's always here with her baby. We name her Labu.
It means "pumpkin" in Malay, because she's really cute.
Priscillia doesn't always hang out in luxury resorts.
She studies colugo all over Malaysia,
collaborating with other scientists.
It was on one such research trip to the hills of Penang
that Priscillia's colleague, Lim Lee-Sim,
first made a recording of an unknown ultrasound call.
Bat expert Sim knew it wasn't a bat's call,
but couldn't identify what animal had made the sound.
When they combined notes,
they realised it had come from the colugo.
It was a brand-new discovery.
The scientists thought it must be a signal to warn others
of a predator approaching,
similar to calls known from rodents like squirrels and rats.
But, in colugos, it was a game-changer.
This animal, previously thought of as solitary,
was communicating in a social group.
What I want to study next is what this ultrasound call means.
Using ultrasound in mammals is not uncommon.
For example, dogs can hear ultrasound,
but not all mammals can actually communicate
using those ultrasounds.
Tonight, Priscillia and Sim are going to try to test their
colugo predator warning theory for the very first time.
LEE-SIM: So this is the colugo...
Signal. ..call.
Signal.
These two little dots, here.
And this. And this. And this. And this, as well.
So this is the call that we recorded three years ago.
Yeah. So we hope, tonight, we can detect
these type of call signal again.
We think they develop these abilities to be able
to avoid predators,
because we think that most of the known predators of the colugo
cannot actually hear those ultrasound.
So it's actually really clever, because the predator
doesn't know that they warn each other.
Oh, this is really exciting.
I like this kind of night.
When you're trying something for the first time,
and we don't know what's going on.
Yeah. This is really nice.
As is always the case with new discoveries,
one answer leads to many more questions.
We don't know if it's a specific population who make them,
or if all of the colugos are making those calls.
Or if it's seasonal.
If, later on, we can see double signals,
overlapping of two sounds,
then we know the colugo is replying. Replying, yeah.
We are actually going to play back those calls
with the specific equipment to see if they react to it
and if they respond to it.
And this will be done for the first time.
So it's really exciting, because it's never been done before
for colugos in the world.
Yeah? I've got a strong signal.
Oh, we have a colugo! Right in front.
Yes, it's working. This way! This way!
OK. I'm so excited it works.
Priscillia and Sim's initial findings are surprising.
There is no more call. Still no more call.
Huh? This is interesting. I was not expecting that.
They stopped calling when we actually put the call.
There is different theories, but we are not really sure what.
But I'm thinking, personally, if it's a call we recorded,
you know, in another place,
so it's a call from another individual,
from another family group.
So maybe the call is slightly different
between the different family groups or different area.
And that means maybe they don't recognise that one
and they stop calling.
Maybe.
Unlocking the colugo's secret language is not going to be easy.
It's something we need to look more into it,
because we are not really sure what's going on.
So I think we need, yeah, a few weeks of, like,
playback recording and then we can figure out what's going on.
But this is an interesting response, though.
Yeah, I think it's really interesting
because it's the first time we are trying
and we already have a reply from them.
We already have a response, right, Sim?
So it's, like, really good.
Like, we are really excited about that.
A new discovery, maybe.
Priscillia and Sim's incredible new discovery
on the colugo paves the way to find new ultrasonic communicators.
It's through the work of these dedicated scientists,
together with new technology,
that is now giving us a window into the world
of clever animal communication.
We're only now beginning to go beyond our limited senses,
but it's still very early days.
You know, I've always been jealous of that fictional character,
Dr Dolittle.
He could talk to the animals.
Imagine what you could say to them!
Imagine listening to them in return!
Imagine the conversations you could have!
Sadly, at this point in time, imagine is all we can do.
We can't break into their systems of communications
because we don't have their senses -
of sight, of hearing, of smell, of touch.
We might be living on the same planet,
but we're also living in very different worlds.
Next time, I'll be looking at nature's best architects
and construction workers -
as we discover more Animal Einsteins.