01x01 - Seeing in Colour

[bunniefuu]

SIR DAVID ATTENBOROUGH:

The natural world is full of colours.

Colours that attract attention.

Colours that blend beautifully

with their background.

And colours that create

extraordinary displays.

MACAWS SCREECH

There are few animals

more brilliantly coloured

than these scarlet macaws.

Animals can use colour

for all kinds of different reasons,

and some have colours

that we ourselves can't even see.

But with new cameras

some developed

especially for this series

we can reveal a world that has

long been hidden from our eyes.

A world of colours

that only some animals can see.

Secret communication channels

for the most private of messages,

and colours so bold and brilliant,

they dazzle our senses.

Whether to win a mate

..or beat a rival

..to warn off an enemy

..or to hide from one.

We will reveal extraordinary stories

about life in colour.

MACAWS SCREECH

The rocky hills of southern India.

PEAFOWL SQUAWK

The stage is set for a performance

of one of the most spectacular

dances in the natural world.

PEAFOWL SQUAWK

Peacocks are gathering.

This surely is one of the most

glamorous of all sights in nature.

150 shimmering eyespots,

carried on tail feathers

that are two metres long.

So, how did such glories evolve?

It seems it's all down

to the female.

The brighter a male's colours

and the greater the number

of his feathery eyespots,

the more attractive

she will find him.

But colours and plumes like these

come at a cost.

The immense tail

makes flying difficult.

The males are literally weighed down

by their feathers.

Yet the colours they carry

are clearly very important to them.

So, why and how has colour

taken on such value?

To understand that, we have to think

back to when it all began.

700 million years ago,

our planet was far less colourful.

But the first animals, it seems,

had eyes that were unable

to distinguish colours anyway.

Gradually, however, this changed.

I am in Costa Rica.

A good place to see

how valuable colour can be.

This toucan likes fruit,

and its ability to choose ripe fruit

from unripe depends on colour,

because the ripe ones are black.

And this capacity —

choosing between different colours

was a very important stage

in the evolution of colour vision.

Birds, close relatives of dinosaurs,

appeared before mammals.

The first mammals,

as far as we can tell,

were mostly nocturnal.

Colours are not easily

distinguishable at night,

so why evolve the ability

to detect them?

So it seems that the first mammals

themselves were not very colourful.

And this is still

largely true today.

Most are shades

of black and white

..or brown.

But there are exceptions.

And one of the most dramatic

lives in the forests of Gabon,

in West Africa.

These monkeys are mandrills,

a kind of baboon.

They live in large troops.

Most are females and youngsters,

both of which are brown.

But the males are different.

They, when they're young, have

very plain faces with naked muzzles.

FLIES BUZZ

As they grow,

their faces begin to change.

Testosterone begins to flow

through their veins.

THEY GRUN

When they're about six years old,

they leave the troop

and start to fend for themselves.

As they become sexually mature,

colour appears in their faces.

And what colour!

Mandrill males are the biggest

of all monkeys

..weighing over 30 kilos,

enormously, frighteningly powerful.

And their colours say so.

SCREECHING

It is not only his face

which is coloured.

So is his rump.

Both are fearless declarations

of his health and strength.

And this male is more than happy

to prove just how strong he is

should any male

dare to challenge him.

Not surprisingly, mandrill eyes are

particularly sensitive to colour.

And it's the brightness of their

colours which signals their status.

SCREECHING

There are four males in this troop,

and they're constantly flexing their

muscles and displaying their colours

to establish who is the strongest.

And not all disputes

are settled peacefully.

They emphasise their ferocity

by gestures,

such as grinding their teeth.

TEETH CLICK TOGETHER LOUDLY

If that doesn't work,

the highest—ranking male will fight.

THEY GRUN

And the others know it.

It's better to let colour

do the talking.

HE GRUNTS

Mandrills see the world

much as we do

and have three kinds

of colour—sensitive cells.

But another group of animals

has colour vision

that's far superior

to that of any mammal

birds.

BIRDS SQUAWK

Their ability varies

from group to group,

but you can judge how good they are

from the colours they use

to signal to one another.

Hummingbirds have excellent

colour vision,

because that enables them

to spot brightly coloured flowers,

which contains the nectar

on which they feed.

WINGS HUM

So, this artificial feeder

is a big success.

Brightly coloured down here

and containing sugar solution —

artificial nectar — up there.

But hummingbirds also use

their ability to see colour

in a different way —

to attract a mate.

Most species live in South America,

where there are flowers of some sort

all year round.

A few, however,

have spread northwards

into the deserts

of the American Southwest.

In this vastness,

it's hard to get noticed.

Especially if you are a small

hummingbird looking for a mate.

But this male Costa's hummingbird

uses his colours

to send a secret message.

Out in the open, flashy colours

can attract unwanted attention,

so he keeps them hidden

most of the time.

A slight turn of the head, however,

provides a tantalising glimpse

of what he has to offer.

He's spotted a female.

She's feeding.

Hummingbirds live fast lives

and need plenty of fuel.

So if he is to attract

her attention,

he needs something eye—catching.

Time to reveal his colours.

WINGS HUM

Erecting the iridescent feathers

on his neck,

he positions himself

to catch the sunlight.

Seen at just the right angle,

his colours are dazzling.

Aerobatics like these

take a lot of energy,

so his performance can give her

clues about his health and fitness.

Every second she takes to decide

burns up his energy reserves.

So he can only hover for so long.

At last, his colours

have persuaded her.

Displaying your colours is easy

out in the open.

Birds which live

in dark forests, however,

have to work harder to get noticed.

The rainforests of New Guinea.

Here, the trees stand 30 metres tall,

with their crowns forming

a near continuous canopy.

But here and there,

there's a small gap

through which a shaft of light

illuminates a patch

on the forest floor.

A stage for one of

the most versatile dancers

in the natural world.

A bird of paradise.

There are over 30 different species.

This one — understandably —

is called

the magnificent bird of paradise.

A male.

Before starting his show,

he clears his stage.

The bare brown earth will make

his colours stand out better.

He takes particular care

to remove anything green.

That colour will be the main feature

of his display

and he doesn't want any competition.

Satisfied at last.

A sapling in the centre will serve

as his dancing pole.

His costume must be immaculate.

Plumes like these

need careful attention.

Time to summon the audience.

HE CHIRPS

CHIRPING CONTINUES

The first to appear

are all young males.

They won't develop their colours

until they're seven years old.

They have come

to watch and to learn.

HE CHIRPS

At last, a female.

She looks much like a young male

to our eyes

..but he can clearly

tell the difference.

She will judge him

by his performance

and the brightness of his feathers.

She does that

from directly above him.

He puffs up his feathers

and swings round

to show her his colours.

For years, naturalists only watched

his performance from ground level.

But the female does so from above.

And from there, his brilliant

green colours stand out vividly

against the brown of the ground.

A pair of bare, quivering quills

sprouting from his tail

add to the excitement.

This is one of the most complex

of all courtship dances,

and we're still unaware

of the details

that she may regard as critical.

The prize—giving, however,

is unmistakable.

The colour vision of birds

is mostly excellent.

But that of many insects

is almost as good.

BIRDS CHIRP AND CHATTER

Butterflies.

They too have evolved an astonishing

variety of colours and patterns.

The wings are covered by tiny

scales, like tiles on a roof,

and it's they that produce

some of the colours.

Some have pigments.

Others reflect light to produce

a shimmering iridescence,

with colours that change

according to the angle

from which they're viewed.

But some butterflies use colours

that are invisible to our eyes.

BUMBLEBEES BUZZ

The glorious colours

of an English meadow in bloom

is a delight

to the eyes of many of us.

But their purpose is not

to appeal to US,

it's to attract insects

such as butterflies and bees.

Most of these plants depend

on insects to pollinate them,

and they use their bright colours

in order to attract insects.

But to understand

what an insect sees,

we have to be able to see it

through their eyes

and from their perspective.

And, happily, we've got a camera

that enables us to do just that.

This camera set—up lets us look at

that flower in two different ways.

This camera is

an ultraviolet camera,

because it has a filter there

that only lets through

ultraviolet light.

But at the same time, this filter

also reflects normal light,

and that comes into this camera,

and that shows what we can see.

So I can compare the two

very easily.

That's what we can see

..and that's what the insect sees.

Flowers have evolved

these ultraviolet markings

for the benefit of insects

such as butterflies.

This particular one lives in the

rainforests of eastern Australia.

It's a blue moon butterfly — a male.

You might not think that it's

the most colourful you've ever seen,

but with our ultraviolet camera,

his wings take on a magical look.

The brighter his patches, the more

attractive he is to females.

But ultraviolet markings like these

can also be seen

by the blue moon's main predators.

Birds can see them just as clearly.

So flying around with a bright

signal like that on your wings

could be dangerous.

For a male, however,

it's worth living dangerously.

If he can mate with one or two

females in his short lifetime,

his colours will have been

a success.

But he has competition.

He will have to defend his territory

if he is to secure a mate.

Butterfly wings are fragile,

so physical combat is to be avoided.

Disputes instead are settled

with aerial displays.

A female has been watching

from the sidelines.

Time to show her his colours.

In her eyes, he's simply dazzling.

MOORHENS PIPE

Ultraviolet colours are

part of the spectrum

that insects can see and we cannot.

Recent discoveries have revealed

that some animals can also see

a characteristic of light

that we cannot detect.

Sunlight contains rays that vibrate

in many different planes.

In polarised light,

they vibrate in only one.

Light may become polarised

when reflected off a shiny surface

such as water.

Unlike us, some animals

can see polarised light,

and they can exploit it

in many ways.

One creature that does so

lives on these vast mudflats

in northern Australia.

These eyes, on st*lks,

belong to a male fiddler crab.

And they can see

in a way that we cannot.

As the tide goes out,

the crabs emerge from their burrows.

His giant claw is too large

to be used in feeding.

Instead, he uses it to attract

the attention of females

by waving it with vigour.

The crabs can see objects that are

close to them reasonably well.

But their long—distance eyesight

is not so good.

Polarised light can help

solve the problem.

Viewed with a new specialist camera,

the mudflats, which reflect

polarised light, are bright

..while the unpolarised crabs appear

darker against their background.

This striking contrast also makes

the large claw more obvious.

The big claw is also used

by the male to defend his burrow.

Not everyone heeds the warning.

Battle over.

But there are more dangerous enemies

to face

aerial predators.

The quicker they can spot them,

the better.

And once again,

polarised light helps them to do so.

TERNS CHATTER

With the coast clear,

a male re—emerges from his burrow.

At last, a female.

With the tide on the turn,

he must work fast to win her over.

And close up,

his colours come into play.

The brightness of his blue back

could be the deciding factor.

She may not look willing,

but the pushing and shoving

are all part of the mating ritual.

One last shove and she's in.

Just in time.

On land, colour is used

in a multitude of different ways.

The same is true in the sea,

but there, colour works

in a very different way.

This is Australia's

Great Barrier Reef,

and its shallow waters

are full of vivid colour.

The inhabitants of the reef

exploit it to the full,

with unparalleled

and dazzling effect.

The orange—red stripes

of the harlequin tuskfish

make it very conspicuous.

But as light filters down

through the water,

more and more of its wavelengths

are absorbed,

and red is the first to disappear.

So, as the harlequin

swims downwards,

his brilliantly coloured red body

looks duller and duller.

Different colours are absorbed

at different rates in the sea,

but some can still be seen

at greater depths.

Yellow and blue travel farthest,

so it's these

that many fish down here use

to signal their identity.

Most fish near the surface

have good colour vision,

but some of the smaller species

can also see ultraviolet colours.

To us, these yellow damselfish

all look very similar.

But using our ultraviolet camera,

here in controlled conditions,

we can see that many fish

have different patterns

that are normally invisible

to our eyes.

And suddenly, it becomes clear

that these two individuals

are in fact different species.

This lemon damselfish

has distinctive spots

on its gill covers.

And this, an Ambon damsel,

has bright reflecting ultraviolet

patches all across the body.

It's a code invisible to us

that allows these fish

to recognise each other

..without attracting the attention

of large predators,

which can't see

in the ultraviolet range.

And it's on the seabed

that you can find

one of the most colourful

sea creatures of all.

The peacock mantis shrimp.

This strange—looking creature's

ancestry

can be traced back

400 million years.

And it has one of the most

versatile kinds of eyes

in the whole of the animal kingdom.

It can rotate its two huge eyes

independently of each other

and in almost any direction.

We have three kinds

of colour receptors,

but the mantis shrimp has 12, each

with a direct link to the brain,

so it can perceive colour

faster than any other animal.

And it can also detect

the difference

between polarised

and unpolarised light.

But, unlike fiddler crabs,

part of its body,

like these paddle—shaped scales,

reflect polarised light

and may be used

to signal to potential mates.

The tail is also highly polarised

and used to plug its burrow

and send a message

to warn off potential rivals.

And by combining

all its visual abilities,

the mantis shrimp has become one of

the most skilful of all predators.

It also packs a powerful punch

from club—like mouthparts

..which it uses with great accuracy.

These clubs deliver the fastest

punch in the animal kingdom,

which we recorded slowed down

and under controlled conditions.

Whether underwater or on land,

colour can be extremely useful.

And the colours an animal develops

can sometimes be influenced

by where it lives and what it eats.

The Atacama Desert in South America.

There are six different species

of flamingos in the world,

and they all prefer to breed

in those most hostile

of environments

salt flats and soda lakes.

We think of flamingos as being

characteristically pink,

but their feathers when they

first appear are in fact white.

FLAMINGOS WARBLE

Their colour comes from their food.

The salty waters in which they feed

are rich in algae and shrimps,

both of which contain red pigments

called carotenoids.

These, over time,

accumulate in their feathers

and give them their bright colour.

FLAMINGOS WARBLE

These youngsters were born

last year.

They still have their first

greyish—white plumage.

It takes time before

the pigments become visible.

Five years will pass before they

become as pink as their parents.

But it's not only the juveniles

which are white.

This adult female raised a chick

last year,

and the effort of doing so

has drained her of colour.

She put all her surplus

food and energy

into producing an egg

and then feeding her chick.

So she will need time to build up

the body reserves needed

to regrow pink feathers and breed.

For those that are old enough

and physically fit,

it's time to find a mate.

Only the pink birds take part

in these courtship dances.

Their colour is an indication

that they're fit and strong.

As they march through the water,

each bird tries to stand out

from the crowd,

and the brightest will be the first

to secure a partner.

The white female can play no part

in this year's display.

She will need to eat

as much as she can

if she is to restore her colour.

Maybe next year she will be able

to rejoin the dance.

Flamingos depend on

their pink colour

to attract a partner and breed.

But there is one tiny animal

in the Central American rainforests

that uses colour not only to attract

but to repel.

This little frog uses colour

as a warning.

Its skin is full of glands

which produce a deadly poison.

So its colour is

a very clear message

"Eat me and you'll regret it!"

You need a vivid message like this

if you are a small, soft—skinned,

bite—sized mouthful

living in a dark, dense forest.

BIRDS SQUAWK

OMINOUS MUSIC

The rainforest can be a scary place.

There are hungry animals everywhere.

For many, it's best

to keep a low profile.

But this little frog doesn't.

It's a strawberry poison—dart frog,

and it's not much bigger

than your fingernail.

And yet he is one of

the deadliest creatures here.

His bright skin secretes a toxin.

In the mouth of a predator,

it can cause respiratory failure,

convulsions and death.

Predators recognise his colour

as a sign of danger and avoid him.

Such frogs also live on a group

of islands just off Panama

called Bocas del Toro.

Living in isolation,

frogs on each island evolved

their own distinctive colours.

There is a different one

on each island

..and yet they're all

the same species.

They're different because

the diet on some islands

makes some more poisonous

than others,

and the more poison a frog has,

the more brightly coloured it is.

On Solarte Island,

a red male is busy calling.

HE CLICKS

This is his patch

and he's looking for a female.

He should be popular

females prefer bright, shiny skin,

which is a sign of fitness.

His colour is also an indication

to other males of his strength.

He spots an intruder.

He's about the same size,

but he's a paler colour.

And he doesn't challenge

the brighter frog.

But this one is a different matter.

MEXICAN STANDOFF—STYLE MUSIC

He IS a contender.

Nothing for it but to fight it out.

That did it.

He won't be back for a while.

And the reward — a new mate.

For these tiny frogs,

colour is central

to all aspects of their lives

for protection, to dominate rivals,

and to find a partner.

For them, life is colour.

When I started working in television

in the 1950s,

all broadcasts were

in black and white,

and conveying animal colour

took a leap of the imagination

on the viewer's part.

Well, those are only some of the

birds of paradise we brought back,

but there's one more

I'd like to show you

the king bird of paradise.

Its feathers are brilliant red

except for its white underparts.

When colour TV arrived

almost 20 years later,

we were suddenly able to show

some of the wonderful colours

of the natural world.

Since then,

electronic cameras have made

extraordinary technical advances

into high definition

and even ultra high definition.

But we've always known that

there's another world of colour,

one that only some animals can see.

In these programs,

new camera technology

has provided a window into

these hitherto invisible worlds.

And one of these is

that revealed by polarised light.

It plays a crucial role

in the lives of many animals,

including these small fiddler crabs

in Darwin, Australia.

We worked with a team of scientists

to develop a unique and pioneering

camera system

to reveal this hidden world.

100% here. Alright

SIR DAVID: The camera detects

areas of polarisation,

such as the light that passes

through polarising sunglasses.

Put it to 100% here

SIR DAVID: It then combines vertical

and horizontal polarisation

to show the contrast between

polarised and unpolarised light.

With this new camera,

the team hoped to find out

how fiddler crabs use polarised

light to signal to each other.

But this camera had been developed

in sterile, controlled conditions,

and these fiddler crabs live

in one of the least sterile

environments on earth

Australia's tropical mudflats.

Quite a challenge

for the cameraman, Mark Lamble.

That mudflat, it's just a really

extreme environment to work

blazing sun overhead,

really high humidity

and almost no airflow.

SIR DAVID: The camera needed

to be half buried in mud

to get a fiddler crab's eye view.

Whether the camera would work here,

no—one could be sure.

I'm slightly worried.

Hopefully we're not going to miss

that special moment

as the camera is not going to work.

But I think we will be OK.

Good luck.

—Thank you.

SIR DAVID: Once in position,

Mark settled down for an uncomfortable wait.

If the crabs detect

the slightest movement,

they disappear into their burrows.

Again

..and again.

I have to be really still,

or they will not come out at all.

I'd love to be able to have

an umbrella over me.

So, anything higher than me is just

not tolerated by the fiddler crabs.

They just won't come up.

SIR DAVID:

But amazingly,

the camera survived the heat,

the humidity and the caustic brine,

and eventually Mark was able

to capture for the first time

a fiddler crab's world

in polarised light.

Light reflected from

the crabs' bodies is unpolarised,

so they look dark.

This makes them stand out

against the mudflats,

from which the reflected light

is polarised.

They can see things

that we can only imagine.

When you look up

and you see a bird fly over,

it's a white bird

against a white sky,

whereas when they look up,

it's just this total silhouette

with the polarisation

and they can see birds coming

from miles away.

And often I'm filming and they'll

all bolt down their holes,

and I'll wonder why they've done it,

and it's just because

they've spotted a bird

way earlier than I would have

been able to see it.

SIR DAVID:

So, polarised light helps the crabs

pick out distant potential mates,

rivals and predators more quickly

against their bright

polarised background.

And for Viktor,

it was the first time

he had seen the camera

he had developed in the lab

revealing the world in the way

these tiny creatures see it.

It's an amazing footage

you've captured, Mark. It's really amazing.

You really put the system

to its limits today.

SIR DAVID: But there was one even bigger

challenge for the camera

one that lay farther out to sea.

Underwater, only crustaceans,

cephalopods and a few fish

are known to be able to see

and react to polarised light.

But there is one animal here

that exploits this ability

in a really complex way.

The peacock mantis shrimp.

It's not only able

to detect polarisation,

but has patches on its body that

reflect light in a polarised form,

and it uses them to signal

to others of their own kind

in ways that we cannot normally see.

Professor Justin Marshall

of Queensland University

has adapted the polarising camera

to work underwater.

So, here we go, Rory.

This is the camera that's

going to show us polarisation.

SIR DAVID: Rory McGuiness,

the team's underwater cameraman,

arrives to see the latest version

of the camera.

So, you've obviously done

a lot of work to get this

into an underwater housing.

—Yep, that's right.

So, you can see in here there's

a computer that runs the camera.

There's quite a lot of engineering

going on in there.

SIR DAVID: Taking the camera for its first

test underwater was a tense moment.

Computers and salt water

don't usually mix well.

Having found a suitable spot,

it was time for the camera's

first critical test.

A leak could be disastrous.

But all is well.

Now they need a mantis shrimp.

OVER RADIO: Looks like

a promising area, Justin.

OVER RADIO:

It looks perfect, Rory.

So, we're looking for a hole

with coral around it.

Hey, look!

Is that a mantis shrimp hole?

SIR DAVID:

The hole's resident soon appeared.

It was time for the camera

to show what it could do.

As the shrimp turns,

the polarised camera shows that

its tail has a shimmering fringe,

invisible in normal light.

JUSTIN:

Look at that. That's extraordinary!

Life in polarised light.

And this is the first time

..we've been able to do this

with this very special camera.

SIR DAVID: The light on the ocean floor

is unpolarised.

So, in complete reverse

to the fiddler crabs,

the mantis shrimps use polarisation

to stand out against

the unpolarised background.

Special pigments polarise the light

reflected from parts of their body,

allowing them to signal to deter

intruders and attract mates.

This camera has revealed to us a

first glimpse into a world of light

that we're only beginning to be

aware of, let alone understand.

In the next episode, the story

of Life In Colour continues

where the stakes are even higher

and colour is the key to survival.

We discover how animals use colour

to hide from predators

and from their prey.

MONKEY BELLOWS