[sweeping orchestral music playing]
[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.
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.
[calling]
[mysterious orchestral music playing]
The rocky hills of Southern India.
The stage is set for a performance
of one of the most spectacular dances in the natural world.
[peacocks calling]
Peacocks are gathering.
[jaunty orchestral music playing]
This, surely,
is one of the most glamorous of all sights in nature.
A hundred and fifty shimmering eyespots,
carried on tail feathers that are six feet long.
So how did such glories evolve?
It seems it's all down to the female.
[calling]
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?
[tranquil orchestral music playing]
To understand that,
we have to think back to when it all began.
Seven hundred 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 of choosing between different colours
was a very important stage in the evolution of colour vision.
[optimistic classical music playing]
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.
[mysterious orchestral music playing]
[bird calling]
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.
As they grow, their faces begin to change.
Testosterone begins to flow through their veins.
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!
[tense orchestral music playing]
Mandrill males are the biggest of all monkeys,
weighing over 30 kilos.
Enormously, frighteningly powerful.
And their colours say so.
[mandrills shrieking]
[mandrill shrieking]
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.
[tense orchestral music building]
[mandrill shrieking]
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.
If that doesn't work,
the highest-ranking male will fight…
[mandrill grunting aggressively]
and the others know it.
It's better to let colour do the talking.
[grunting]
Mandrills see the world much as we do
and have three kinds of colour-sensitive cells.
[serene orchestral music playing]
But another group of animals has colour vision that's far superior
to that of any mammal.
Birds.
[birds calling]
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.
[whispering] Hummingbirds have excellent colour vision,
because that enables them to spot brightly coloured flowers,
which contains the nectar on which they feed.
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.
[birds chirping, calling]
A few, however, have spread northwards
into the deserts of the American Southwest.
[tranquil orchestral music playing]
In this vastness,
it's hard to get noticed,
especially if you're 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.
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.
[mysterious orchestral music playing]
Birds which live in dark forests, however,
have to work harder to get noticed.
The rainforests of New Guinea.
Here, the trees stand 100 feet 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.
[calling]
[calling 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.
[calling]
At last, a female.
She looks much like a young male to our eyes,
but he can clearly tell the difference.
[whimsical orchestral music playing]
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 this 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.
[serene orchestral music playing]
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.
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 setup 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.
[enchanting orchestral music playing]
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's 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.
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.
[whimsical orchestral music playing]
These eyes, on stalks, 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.
[playfully tense orchestral music playing]
Battle over.
But there are more dangerous enemies to face.
Aerial predators.
The quicker they can spot them the better.
[birds screeching]
And, once again, polarised light helps them to do so.
[whimsical orchestral music playing]
With the coast clear,
a male reemerges 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.
[enchanting orchestral music playing]
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,
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.
[jaunty orchestral music playing]
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.
[tense orchestral music playing]
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,
and it's guided by its extraordinary vision.
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.
[sweeping orchestral music playing]
The Atacama Desert in South America.
[bird calling]
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.
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.
[tranquil orchestral music playing]
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.
[sweeping orchestral music playing]
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.
[menacing orchestral music playing]
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.
[calling rapidly]
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.
[tense orchestral music playing]
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.
[Western-style guitar playing]
He is a contender.
Nothing for it but to fight it out.
[jaunty orchestral music playing]
[frog calling]
That did it.
He won't be back for a while.
[tranquil orchestral music playing]
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.
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.
[monkeys calling]
[snorts]
[sweeping orchestral music playing]