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The natural world is
full of colours...
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..colours that attract attention...
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00:00:35,160 --> 00:00:38,040
..colours that blend beautifully
with their background...
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..and colours that create
extraordinary displays.
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00:00:51,280 --> 00:00:54,720
There are few animals more
brilliantly coloured than
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00:00:54,720 --> 00:00:56,360
these scarlet macaws.
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00:00:57,600 --> 00:01:01,680
Animals can use colour for all
kinds of different reasons,
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00:01:01,680 --> 00:01:05,360
and some have colours that
we ourselves can't even see.
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00:01:08,360 --> 00:01:12,640
But with new cameras, some developed
especially for this series,
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00:01:12,640 --> 00:01:16,760
we can reveal a world that has
long been hidden from our eyes...
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00:01:18,960 --> 00:01:22,360
..a world of colours that
only some animals can see.
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00:01:24,160 --> 00:01:29,600
Secret communication channels
for the most private of messages,
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and colours so bold and brilliant
they dazzle our senses.
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Whether to win a mate...
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..or beat a rival...
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..to warn off an enemy...
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..or to hide from one...
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..we will reveal extraordinary
stories about life in colour.
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The rocky hills of Southern India.
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The stage is set for
a performance of one
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of the most spectacular
dances in the natural world.
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PEACOCKS CALL
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Peacocks are gathering.
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This, surely, is one of the most
glamorous of all sights in nature.
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150 shimmering eyespots,
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carried on tail feathers
that are six feet long.
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00:03:33,760 --> 00:03:36,840
So how did such glories evolve?
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It seems it's all
down to the female.
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HE CALLS
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The brighter a male's colours
and the greater the number of
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his feathery eyespots, the more
attractive she will find him.
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00:04:13,120 --> 00:04:16,840
But colours and plumes
like these come at a cost.
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00:04:25,040 --> 00:04:28,240
The immense tail makes
flying difficult -
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the males are literally
weighed down by their feathers.
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00:04:36,160 --> 00:04:39,560
Yet the colours they carry
are clearly very important to them.
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00:04:42,240 --> 00:04:45,760
So why and how has colour
taken on such value?
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00:04:53,200 --> 00:04:58,560
To understand that, we have to
think back to when it all began.
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00:05:02,840 --> 00:05:07,400
700 million years ago,
our planet was far less colourful.
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00:05:09,240 --> 00:05:11,520
But the first animals, it seems,
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00:05:11,520 --> 00:05:15,440
had eyes that were unable to
distinguish colours anyway.
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Gradually, however, this changed.
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I am in Costa Rica...
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..a good place to see how
valuable colour can be.
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This toucan likes fruit,
and its ability to choose ripe
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fruit from unripe depends on colour
because the ripe ones are black.
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And this capacity of choosing
between different colours was
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a very important stage in the
evolution of colour vision.
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00:06:06,520 --> 00:06:11,280
Birds, close relatives of dinosaurs,
appeared before mammals.
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00:06:16,120 --> 00:06:20,320
The first mammals, as far as we
can tell, were mostly nocturnal.
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00:06:21,600 --> 00:06:24,640
Colours are not easily
distinguishable at night,
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so why evolve the ability
to detect them?
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00:06:30,720 --> 00:06:35,360
So it seems that the first mammals
themselves were not very colourful.
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00:06:36,840 --> 00:06:39,320
And this is still
largely true today.
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Most are shades of
black and white...
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..or brown.
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00:06:52,640 --> 00:06:54,200
But there are exceptions.
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00:06:55,520 --> 00:06:59,280
And one of the most dramatic
lives in the forests of Gabon
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in West Africa.
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These monkeys are mandrills -
a kind of baboon.
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They live in large troops.
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Most are females and youngsters,
both of which are brown.
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But the males are different.
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They, when they're young, have very
plain faces with naked muzzles.
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As they grow,
their faces begin to change.
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Testosterone begins to flow
through their veins.
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When they're about six years old,
they leave the troop
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and start to fend for themselves.
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00:08:09,520 --> 00:08:13,920
As they become sexually mature,
colour appears in their faces...
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..and what colour!
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00:08:26,920 --> 00:08:30,360
Mandrill males are the biggest
of all monkeys...
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00:08:32,360 --> 00:08:34,600
..weighing over 30 kilos -
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enormously, frighteningly powerful.
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And their colours say so.
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SCREECHING
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HISSING
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It is not only his face
which is coloured.
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So is his rump.
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00:08:56,360 --> 00:09:00,680
Both are fearless declarations
of his health and strength.
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00:09:04,720 --> 00:09:09,080
And this male is more than happy
to prove just how strong he is...
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00:09:09,080 --> 00:09:11,880
..should any male dare
to challenge him.
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00:09:16,520 --> 00:09:20,520
Not surprisingly, mandrill eyes are
particularly sensitive to colour.
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00:09:24,960 --> 00:09:28,440
And it's the brightness of their
colours which signals their status.
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SCREECHING
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00:09:38,960 --> 00:09:41,440
There are four males in this troop,
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and they're constantly
flexing their muscles
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and displaying their colours to
establish who is the strongest.
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00:09:51,440 --> 00:09:54,480
And not all disputes
are settled peacefully.
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00:10:00,920 --> 00:10:03,720
They emphasise their
ferocity by gestures
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such as grinding their teeth.
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00:10:13,360 --> 00:10:17,000
If that doesn't work, the
highest-ranking male will fight...
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..and the others know it.
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It's better to let
colour do the talking.
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HE COUGHS
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00:10:36,720 --> 00:10:39,960
Mandrills see the world
much as we do
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00:10:39,960 --> 00:10:42,760
and have three kinds of
colour-sensitive cells.
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00:10:46,280 --> 00:10:50,120
But another group of animals
has colour vision that's far
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superior to that of
any mammal - birds.
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00:11:00,800 --> 00:11:04,400
Their ability varies
from group to group,
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00:11:04,400 --> 00:11:07,160
but you can judge how good
they are from the colours
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00:11:07,160 --> 00:11:09,160
they use to signal to one another.
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00:11:11,520 --> 00:11:14,680
Hummingbirds have
excellent colour vision...
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..because that enables them
to spot brightly-coloured flowers
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00:11:21,400 --> 00:11:23,800
which contains the nectar
on which they feed.
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00:11:32,760 --> 00:11:36,760
So this artificial feeder
is a big success -
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00:11:36,760 --> 00:11:39,080
brightly coloured down here,
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00:11:39,080 --> 00:11:42,600
and containing sugar solution,
artificial nectar, up there.
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00:11:48,840 --> 00:11:51,920
But hummingbirds also
use their ability to see
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00:11:51,920 --> 00:11:55,880
colour in a different way -
to attract a mate.
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00:11:58,480 --> 00:12:01,200
Most species
live in South America, where
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there are flowers of some
sort all year round.
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A few, however,
have spread northwards
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into the deserts of
the American Southwest.
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In this vastness,
it's hard to get noticed...
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..especially if you are a small
hummingbird looking for a mate.
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00:12:41,040 --> 00:12:46,280
But this male Costa's hummingbird
uses his colours to send
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a secret message.
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Out in the open, flashy colours
can attract unwanted attention,
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so he keeps them
hidden most of the time.
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00:13:00,280 --> 00:13:02,240
A slight turn of the head, however,
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00:13:02,240 --> 00:13:05,800
provides a tantalising
glimpse of what he has to offer.
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00:13:10,880 --> 00:13:13,200
He's spotted a female.
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00:13:13,200 --> 00:13:14,080
She's feeding.
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00:13:20,920 --> 00:13:25,480
Hummingbirds live fast lives
and need plenty of fuel.
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00:13:25,480 --> 00:13:27,920
So, if he is to attract
her attention,
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he needs something eye-catching.
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Time to reveal his colours!
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00:13:42,440 --> 00:13:45,640
Erecting the iridescent
feathers on his neck,
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he positions himself
to catch the sunlight.
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00:13:55,920 --> 00:13:59,520
Seen at just the right angle,
his colours are dazzling.
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00:14:19,200 --> 00:14:22,200
Aerobatics like these
take a lot of energy,
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so his performance can give her
clues about his health and fitness.
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00:14:31,520 --> 00:14:36,640
Every second she takes to decide
burns up his energy reserves...
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..so he can only hover for so long.
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At last, his colours
have persuaded her.
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00:15:16,280 --> 00:15:19,440
Displaying your colours
is easy out in the open.
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00:15:24,200 --> 00:15:26,760
Birds which live in dark forests,
however,
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have to work harder to get noticed.
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00:15:35,080 --> 00:15:38,080
The rainforests of New Guinea.
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00:15:38,080 --> 00:15:40,840
Here, the trees stand 100 feet tall,
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00:15:40,840 --> 00:15:44,200
with their crowns forming
a near continuous canopy.
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But here and there, there's
a small gap through which
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00:15:50,320 --> 00:15:53,600
a shaft of light illuminates
a patch on the forest floor...
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..a stage for one of
the most versatile
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dancers in the natural world...
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..a bird of paradise.
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00:16:08,600 --> 00:16:10,840
There are over 30 different species.
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This one, understandably,
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is called the magnificent
bird of paradise.
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A male.
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Before starting his show,
he clears his stage.
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The bare brown earth will make
his colours stand out better.
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He takes particular care
to remove anything green.
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That colour will be the main
feature of his display,
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and he doesn't want any competition.
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00:17:00,640 --> 00:17:02,200
Satisfied at last.
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00:17:03,880 --> 00:17:07,880
A sapling in the centre will
serve as his dancing pole.
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His costume must be immaculate.
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Plumes like these need
careful attention.
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00:17:32,680 --> 00:17:34,720
Time to summon the audience.
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HE CHIRPS
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HE CHIRPS
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The first to appear
are all young males.
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They won't develop their colours
until they're seven years old.
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They have come to watch
and to learn.
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00:18:09,680 --> 00:18:12,680
HE CHIRPS
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At last, a female.
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00:18:16,800 --> 00:18:19,600
She looks much like a
young male to our eyes...
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00:18:21,600 --> 00:18:23,680
..but he can clearly
tell the difference.
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00:18:28,720 --> 00:18:30,920
She will judge him
by his performance
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00:18:30,920 --> 00:18:33,200
and the brightness of his feathers.
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00:18:35,680 --> 00:18:38,480
She does that from
directly above him.
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He puffs up his feathers and swings
round to show her his colours.
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For years, naturalists only watched
his performance from ground level.
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00:19:14,120 --> 00:19:16,680
But the female does so from above.
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00:19:22,080 --> 00:19:25,680
And from there, his brilliant
green colours stand out
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vividly against the
brown of the ground.
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00:19:32,360 --> 00:19:37,080
A pair of bare, quivering quills
sprouting from his tail
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add to the excitement.
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00:19:43,600 --> 00:19:47,920
This is one of the most complex
of all courtship dances, and we're
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still unaware of the details
that she may regard as critical.
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The prize-giving, however,
is unmistakable.
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00:20:19,680 --> 00:20:22,160
The colour vision of birds
is mostly excellent.
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00:20:24,720 --> 00:20:27,400
But that of many insects
is almost as good.
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00:20:34,800 --> 00:20:35,800
Butterflies.
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They too have evolved an astonishing
variety of colours and patterns.
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00:20:59,960 --> 00:21:05,000
The wings are covered by tiny
scales like tiles on a roof,
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00:21:05,000 --> 00:21:07,520
and it's they that produce
some of the colours.
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00:21:12,160 --> 00:21:13,520
Some have pigments.
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00:21:15,200 --> 00:21:20,440
Others reflect light to produce
a shimmering iridescence with
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00:21:20,440 --> 00:21:24,240
colours that change according to the
angle from which they are viewed.
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00:21:37,240 --> 00:21:42,120
But some butterflies use colours
that are invisible to our eyes.
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00:21:51,280 --> 00:21:55,920
The glorious colours of an
English meadow in bloom is
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00:21:55,920 --> 00:21:58,160
a delight to the eyes of many of us.
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00:21:59,440 --> 00:22:03,200
But their purpose is
not to appeal to us -
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00:22:03,200 --> 00:22:07,760
it's to attract insects,
such as butterflies and bees.
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00:22:10,120 --> 00:22:15,760
Most of these plants
depend on insects to pollinate them,
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00:22:15,760 --> 00:22:19,320
and they use their bright colours
in order to attract insects.
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00:22:20,480 --> 00:22:24,400
But to understand
what an insect sees,
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00:22:24,400 --> 00:22:27,840
we have to be able to see it
through their eyes and from
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00:22:27,840 --> 00:22:32,400
their perspective, and happily
we've got a camera that enables us
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00:22:32,400 --> 00:22:33,520
to do just that.
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00:22:38,200 --> 00:22:40,320
This camera set-up lets us look at
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00:22:40,320 --> 00:22:42,480
that flower in two different ways.
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This camera is an ultraviolet camera
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00:22:46,560 --> 00:22:49,120
because it has a filter there that
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00:22:49,120 --> 00:22:52,080
only lets through ultraviolet light.
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00:22:52,080 --> 00:22:54,440
But at the same time, this filter
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00:22:54,440 --> 00:22:56,720
also reflects normal light,
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00:22:56,720 --> 00:23:00,920
and that comes into this camera,
and that shows what we can see.
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00:23:00,920 --> 00:23:05,560
So I can compare the two very
easily. That's what we can see...
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00:23:09,480 --> 00:23:11,240
..and that's what the insect sees.
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00:23:14,280 --> 00:23:17,360
Flowers have evolved these
ultraviolet markings
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00:23:17,360 --> 00:23:20,840
for the benefit of insects,
such as butterflies.
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00:23:30,240 --> 00:23:35,280
This particular one lives in the
rainforests of eastern Australia.
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00:23:35,280 --> 00:23:38,480
It's a blue moon butterfly - a male.
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00:23:44,080 --> 00:23:48,520
You might not think that it's the
most colourful you've ever seen
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00:23:48,520 --> 00:23:53,560
but, with our ultraviolet camera,
his wings take on a magical look.
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00:23:59,680 --> 00:24:01,360
The brighter his patches,
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00:24:01,360 --> 00:24:03,520
the more attractive
he is to females.
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00:24:08,920 --> 00:24:11,680
But ultraviolet markings
like these can also
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00:24:11,680 --> 00:24:14,400
be seen by the blue moon's
main predators.
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00:24:17,560 --> 00:24:20,160
Birds can see them just as clearly.
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00:24:24,240 --> 00:24:28,360
So flying around with a bright
signal like that on your wings
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00:24:28,360 --> 00:24:29,360
could be dangerous.
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00:24:35,960 --> 00:24:40,120
For a male, however,
it's worth living dangerously.
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00:24:40,120 --> 00:24:44,120
If he can mate with one or two
females in his short lifetime,
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00:24:44,120 --> 00:24:46,000
his colours will
have been a success.
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00:24:54,280 --> 00:24:55,920
But he has competition.
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00:24:57,920 --> 00:25:01,880
He will have to defend his territory
if he is to secure a mate.
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00:25:05,440 --> 00:25:09,320
Butterfly wings are fragile,
so physical combat is to be avoided.
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00:25:12,560 --> 00:25:16,600
Disputes instead are settled
with aerial displays.
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00:25:34,240 --> 00:25:36,280
Time to show her his colours.
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00:25:55,360 --> 00:25:58,440
In her eyes, he's simply dazzling.
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00:26:14,200 --> 00:26:19,240
Ultraviolet colours are part of the
spectrum that insects can see...
235
00:26:19,240 --> 00:26:20,400
..and we cannot.
236
00:26:23,240 --> 00:26:26,840
Recent discoveries have revealed
that some animals can also
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00:26:26,840 --> 00:26:30,400
see a characteristic
of light that we cannot detect.
238
00:26:32,760 --> 00:26:37,640
Sunlight contains rays that vibrate
in many different planes.
239
00:26:38,960 --> 00:26:42,560
In polarised light,
they vibrate in only one.
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00:26:44,400 --> 00:26:47,040
Light may become polarised
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00:26:47,040 --> 00:26:49,960
when reflected off a shiny
surface, such as water.
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00:26:51,720 --> 00:26:56,280
Unlike us, some animals
can see polarised light,
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00:26:56,280 --> 00:26:59,080
and they can exploit
it in many ways.
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00:27:04,120 --> 00:27:06,160
One creature that does so
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00:27:06,160 --> 00:27:10,280
lives on these vast mudflats
in northern Australia.
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00:27:15,760 --> 00:27:20,240
These eyes - on stalks -
belong to a male fiddler crab.
247
00:27:23,320 --> 00:27:26,040
And they can see in a way
that we cannot.
248
00:27:34,400 --> 00:27:38,200
As the tide goes out,
the crabs emerge from their burrows.
249
00:27:46,560 --> 00:27:50,800
His giant claw is too large
to be used in feeding.
250
00:27:53,880 --> 00:27:57,920
Instead, he uses it to attract
the attention of females...
251
00:27:57,920 --> 00:28:00,000
..by waving it with vigour!
252
00:28:03,200 --> 00:28:06,840
The crabs can see objects that are
close to them reasonably well...
253
00:28:09,960 --> 00:28:13,440
..but their long-distance
eyesight is not so good.
254
00:28:18,480 --> 00:28:21,840
Polarised light can help
solve the problem.
255
00:28:26,440 --> 00:28:29,880
Viewed with a new specialist
camera, the mudflats,
256
00:28:29,880 --> 00:28:33,040
which reflect polarised
light, are bright...
257
00:28:36,160 --> 00:28:40,840
..while the unpolarised crabs appear
darker against their background.
258
00:28:42,720 --> 00:28:46,880
This striking contrast also makes
the large claw more obvious.
259
00:28:49,960 --> 00:28:54,200
The big claw is also used
by the male to defend his burrow.
260
00:28:59,080 --> 00:29:01,280
Not everyone heeds the warning.
261
00:29:16,000 --> 00:29:17,120
Battle over.
262
00:29:20,280 --> 00:29:23,560
But there are more dangerous
enemies to face -
263
00:29:23,560 --> 00:29:24,880
aerial predators.
264
00:29:26,480 --> 00:29:29,760
The quicker they can spot them,
the better
265
00:29:29,760 --> 00:29:33,520
and, once again,
polarised light helps them to do so.
266
00:29:47,240 --> 00:29:51,480
With the coast clear,
a male re-emerges from his burrow.
267
00:29:55,320 --> 00:29:57,160
At last, a female.
268
00:30:04,120 --> 00:30:08,120
With the tide on the turn,
he must work fast to win her over.
269
00:30:15,280 --> 00:30:18,080
And close up,
his colours come into play.
270
00:30:19,560 --> 00:30:23,560
The brightness of his blue back
could be the deciding factor.
271
00:30:32,920 --> 00:30:34,880
She may not look willing,
272
00:30:34,880 --> 00:30:38,800
but the pushing and shoving are
all part of the mating ritual.
273
00:30:43,680 --> 00:30:46,520
One last shove and she's in...
274
00:30:49,760 --> 00:30:50,920
..just in time.
275
00:31:05,360 --> 00:31:09,600
On land, colour is used
in a multitude of different ways.
276
00:31:10,720 --> 00:31:13,960
The same is true in the sea,
but there,
277
00:31:13,960 --> 00:31:16,480
colour works in a very
different way.
278
00:31:26,920 --> 00:31:30,000
This is Australia's
Great Barrier Reef,
279
00:31:30,000 --> 00:31:33,440
and its shallow waters
are full of vivid colour.
280
00:31:39,760 --> 00:31:43,480
The inhabitants of the reef
exploit it to the full,
281
00:31:43,480 --> 00:31:46,200
with unparalleled
and dazzling effect.
282
00:32:02,960 --> 00:32:06,760
The orange-red stripes
of the harlequin tuskfish
283
00:32:06,760 --> 00:32:08,240
make it very conspicuous.
284
00:32:12,480 --> 00:32:14,760
But as light filters
down through the water,
285
00:32:14,760 --> 00:32:17,720
more and more of its wavelengths
are absorbed...
286
00:32:19,360 --> 00:32:21,800
..and red is the first to disappear.
287
00:32:24,160 --> 00:32:27,320
So, as the harlequin
swims downwards,
288
00:32:27,320 --> 00:32:31,120
his brilliantly coloured red body
looks duller and duller.
289
00:32:42,720 --> 00:32:47,600
Different colours are absorbed
at different rates in the sea,
290
00:32:47,600 --> 00:32:50,440
but some can still be
seen at greater depths.
291
00:32:54,280 --> 00:32:56,760
Yellow and blue travel farthest,
292
00:32:56,760 --> 00:33:01,320
so it's these that many fish down
here use to signal their identity.
293
00:33:07,560 --> 00:33:10,960
Most fish near the surface
have good colour vision,
294
00:33:10,960 --> 00:33:15,400
but some of the smaller species
can also see ultraviolet colours.
295
00:33:19,520 --> 00:33:23,120
To us, these yellow damselfish
all look very similar.
296
00:33:28,160 --> 00:33:33,120
But using our ultraviolet camera
here in controlled conditions,
297
00:33:33,120 --> 00:33:36,480
we can see that many fish
have different patterns
298
00:33:36,480 --> 00:33:39,280
that are normally
invisible to our eyes.
299
00:33:42,600 --> 00:33:44,920
And suddenly, it becomes clear that
300
00:33:44,920 --> 00:33:48,800
these two individuals are
in fact different species.
301
00:33:52,920 --> 00:33:56,440
This lemon damselfish
has distinctive spots
302
00:33:56,440 --> 00:33:57,600
on its gill covers.
303
00:34:00,240 --> 00:34:03,600
And this, an Ambon damsel,
304
00:34:03,600 --> 00:34:08,440
has bright reflecting ultraviolet
patches all across the body.
305
00:34:11,200 --> 00:34:13,600
It's a code invisible to us
306
00:34:13,600 --> 00:34:16,320
that allows these fish to
recognise each other...
307
00:34:18,840 --> 00:34:22,080
..without attracting the attention
of large predators,
308
00:34:22,080 --> 00:34:24,880
which can't see in the
ultraviolet range.
309
00:34:32,960 --> 00:34:35,720
And it's on the seabed
that you can find
310
00:34:35,720 --> 00:34:38,280
one of the most colourful
sea creatures of all...
311
00:34:44,800 --> 00:34:47,440
..the peacock mantis shrimp.
312
00:34:53,600 --> 00:34:56,400
This strange-looking
creature's ancestry
313
00:34:56,400 --> 00:34:59,320
can be traced back
400 million years...
314
00:35:01,680 --> 00:35:05,320
..and it has one of the most
versatile kinds of eyes in the whole
315
00:35:05,320 --> 00:35:06,920
of the animal kingdom.
316
00:35:12,080 --> 00:35:17,120
It can rotate its two huge eyes
independently of each other
317
00:35:17,120 --> 00:35:18,720
and in almost any direction.
318
00:35:21,480 --> 00:35:25,480
We have three kinds of colour
receptors, but the mantis shrimp
319
00:35:25,480 --> 00:35:29,400
has 12, each with
a direct link to the brain,
320
00:35:29,400 --> 00:35:33,120
so it can perceive colour faster
than any other animal.
321
00:35:35,400 --> 00:35:39,040
And it can also detect
the difference between polarised
322
00:35:39,040 --> 00:35:40,320
and unpolarised light.
323
00:35:44,760 --> 00:35:48,000
But unlike fiddler crabs,
part of its body,
324
00:35:48,000 --> 00:35:52,120
like these paddle-shaped scales,
reflect polarised light...
325
00:35:53,480 --> 00:35:56,520
..and may be used to signal
to potential mates.
326
00:36:03,640 --> 00:36:08,080
The tail is also highly polarised
and used to plug its burrow
327
00:36:08,080 --> 00:36:11,520
and send a message to
warn off potential rivals.
328
00:36:17,640 --> 00:36:20,920
And by combining
all its visual abilities,
329
00:36:20,920 --> 00:36:25,520
the mantis shrimp has become one of
the most skilful of all predators.
330
00:36:37,960 --> 00:36:42,400
It also packs a powerful punch
from club-like mouth parts...
331
00:36:46,280 --> 00:36:48,680
..which it uses with great accuracy.
332
00:36:51,400 --> 00:36:55,680
These clubs deliver the fastest
punch in the animal kingdom,
333
00:36:55,680 --> 00:36:59,880
which we recorded slowed down
and under controlled conditions.
334
00:37:13,040 --> 00:37:18,440
Whether underwater or on land,
colour can be extremely useful.
335
00:37:23,400 --> 00:37:26,800
And the colours an animal
develops can sometimes be
336
00:37:26,800 --> 00:37:30,520
influenced by where it
lives and what it eats.
337
00:37:39,480 --> 00:37:42,520
The Atacama Desert in South America.
338
00:37:54,360 --> 00:37:58,200
There are six different
species of flamingos in the world,
339
00:37:58,200 --> 00:38:01,640
and they all prefer to
breed in those most
340
00:38:01,640 --> 00:38:05,880
hostile of environments -
salt flats and soda lakes.
341
00:38:11,520 --> 00:38:15,680
We think of flamingos as being
characteristically pink,
342
00:38:15,680 --> 00:38:19,280
but their feathers when they
first appear are in fact white.
343
00:38:23,760 --> 00:38:26,360
Their colour comes from their food.
344
00:38:29,880 --> 00:38:34,280
The salty waters in which they feed
are rich in algae and shrimps,
345
00:38:34,280 --> 00:38:38,400
both of which contain red
pigments called carotenoids.
346
00:38:41,600 --> 00:38:44,880
These, over time, accumulate
in their feathers and give them
347
00:38:44,880 --> 00:38:45,880
their bright colour.
348
00:39:03,200 --> 00:39:06,440
These youngsters were
born last year.
349
00:39:06,440 --> 00:39:09,280
They still have their first
greyish-white plumage.
350
00:39:16,000 --> 00:39:18,920
It takes time before the
pigments become visible.
351
00:39:25,080 --> 00:39:29,680
Five years will pass before they
become as pink as their parents.
352
00:39:38,680 --> 00:39:41,760
But it's not only the juveniles
which are white.
353
00:39:47,480 --> 00:39:51,040
This adult female raised
a chick last year,
354
00:39:51,040 --> 00:39:54,560
and the effort of doing so
has drained her of colour.
355
00:39:57,840 --> 00:40:01,680
She put all her surplus food
and energy into producing an egg
356
00:40:01,680 --> 00:40:03,600
and then feeding her chick.
357
00:40:05,960 --> 00:40:09,880
So she will need time to build up
the body reserves needed to
358
00:40:09,880 --> 00:40:12,640
regrow pink feathers and breed.
359
00:40:20,840 --> 00:40:24,200
For those that are old
enough and physically fit,
360
00:40:24,200 --> 00:40:26,040
it's time to find a mate.
361
00:40:29,960 --> 00:40:33,160
Only the pink birds take
part in these courtship dances.
362
00:40:37,640 --> 00:40:41,640
Their colour is an indication
that they're fit and strong.
363
00:41:01,000 --> 00:41:03,320
As they march through the water,
364
00:41:03,320 --> 00:41:06,360
each bird tries to stand
out from the crowd...
365
00:41:07,520 --> 00:41:11,120
..and the brightest will be
the first to secure a partner.
366
00:41:18,240 --> 00:41:22,600
The white female can play no
part in this year's display.
367
00:41:29,640 --> 00:41:32,080
She will need to eat
as much as she can
368
00:41:32,080 --> 00:41:34,160
if she is to restore her colour.
369
00:41:37,600 --> 00:41:42,040
Maybe next year she will be
able to rejoin the dance.
370
00:41:54,160 --> 00:41:58,040
Flamingos depend on their pink
colour to attract a partner
371
00:41:58,040 --> 00:41:59,080
and breed.
372
00:42:02,120 --> 00:42:06,160
But there is one tiny animal in
the Central American rainforests
373
00:42:06,160 --> 00:42:08,400
that uses colour not only
374
00:42:08,400 --> 00:42:10,640
to attract, but to repel.
375
00:42:21,240 --> 00:42:24,320
This little frog uses
colour as a warning.
376
00:42:25,480 --> 00:42:27,760
Its skin is full of glands
377
00:42:27,760 --> 00:42:30,600
which produce a deadly poison,
378
00:42:30,600 --> 00:42:31,720
so its colour is
379
00:42:31,720 --> 00:42:33,200
a very clear message -
380
00:42:33,200 --> 00:42:35,520
eat me and you'll regret it!
381
00:42:39,280 --> 00:42:43,880
You need a vivid message like
this if you are a small,
382
00:42:43,880 --> 00:42:49,240
soft-skinned, bite-sized mouthful
living in a dark, dense forest.
383
00:43:02,240 --> 00:43:05,280
The rainforest can be a scary place.
384
00:43:09,960 --> 00:43:12,600
There are hungry animals everywhere.
385
00:43:27,720 --> 00:43:31,120
For many,
it's best to keep a low profile.
386
00:43:35,760 --> 00:43:37,920
But this little frog doesn't.
387
00:43:39,800 --> 00:43:43,120
It's a strawberry poison-dart frog,
388
00:43:43,120 --> 00:43:45,720
and it's not much bigger
than your fingernail...
389
00:43:46,800 --> 00:43:49,760
..and yet he is one of the
deadliest creatures here.
390
00:43:52,840 --> 00:43:55,400
His bright skin secretes a toxin.
391
00:43:57,800 --> 00:44:01,760
In the mouth of a predator,
it can cause respiratory failure,
392
00:44:01,760 --> 00:44:04,000
convulsions and death.
393
00:44:07,760 --> 00:44:12,320
Predators recognise his colour
as a sign of danger and avoid him.
394
00:44:19,280 --> 00:44:23,400
Such frogs also live on a group
of islands just off Panama
395
00:44:23,400 --> 00:44:25,560
called Bocas del Toro.
396
00:44:27,920 --> 00:44:29,440
Living in isolation,
397
00:44:29,440 --> 00:44:33,440
frogs on each island evolved
their own distinctive colours.
398
00:44:36,640 --> 00:44:39,320
There is a different
one on each island.
399
00:44:43,040 --> 00:44:45,520
And yet they're all
the same species.
400
00:44:51,720 --> 00:44:55,800
They're different because the diet
on some islands makes some
401
00:44:55,800 --> 00:44:58,280
more poisonous than others.
402
00:44:58,280 --> 00:45:02,480
And the more poison a frog has,
the more brightly coloured it is.
403
00:45:11,520 --> 00:45:15,760
On Solarte Island,
a red male is busy calling.
404
00:45:15,760 --> 00:45:23,840
HE CROAKS
405
00:45:25,280 --> 00:45:29,120
This is his patch,
and he's looking for a female.
406
00:45:32,720 --> 00:45:34,240
He should be popular.
407
00:45:34,240 --> 00:45:38,440
Females prefer bright, shiny skin,
which is a sign of fitness.
408
00:45:43,360 --> 00:45:47,600
His colour is also an indication
to other males of his strength.
409
00:45:56,960 --> 00:45:58,360
He spots an intruder.
410
00:45:59,440 --> 00:46:03,040
He's about the same size,
but he's a paler colour.
411
00:46:12,840 --> 00:46:15,800
And he doesn't challenge
the brighter frog.
412
00:46:22,320 --> 00:46:24,760
But this one is a different matter.
413
00:46:27,800 --> 00:46:29,360
He is a contender.
414
00:46:40,840 --> 00:46:43,600
Nothing for it but to fight it out.
415
00:47:25,520 --> 00:47:28,960
That did it -
he won't be back for a while.
416
00:47:37,280 --> 00:47:39,280
And the reward...
417
00:47:39,280 --> 00:47:40,200
..a new mate.
418
00:47:47,040 --> 00:47:51,640
For these tiny frogs, colour is
central to all aspects of their
419
00:47:51,640 --> 00:47:57,400
lives - for protection, to dominate
rivals and to find a partner.
420
00:47:59,040 --> 00:48:02,080
For them, life is colour.
421
00:48:12,160 --> 00:48:15,600
When I started
working in television in the 1950s,
422
00:48:15,600 --> 00:48:19,640
all broadcasts were in black
and white, and conveying animal
423
00:48:19,640 --> 00:48:24,280
colour took a leap of the
imagination on the viewer's part.
424
00:48:24,280 --> 00:48:27,480
Well, those are only some of the
birds of paradise we brought back,
425
00:48:27,480 --> 00:48:29,920
and there's one more
I'd like to show you -
426
00:48:29,920 --> 00:48:32,560
the king bird of paradise.
427
00:48:32,560 --> 00:48:35,880
Its feathers are brilliant red,
except for its white underparts.
428
00:48:38,640 --> 00:48:42,520
When colour TV arrived almost
20 years later, we were suddenly
429
00:48:42,520 --> 00:48:46,160
able to show some of the wonderful
colours of the natural world.
430
00:48:52,680 --> 00:48:56,680
Since then, electronic cameras
have made extraordinary technical
431
00:48:56,680 --> 00:49:01,560
advances into high definition
and even ultra-high definition.
432
00:49:03,240 --> 00:49:06,720
But we've always known that
there's another world of colour -
433
00:49:06,720 --> 00:49:09,680
one that only some animals can see.
434
00:49:14,200 --> 00:49:17,960
In these programmes, new camera
technology has provided
435
00:49:17,960 --> 00:49:21,280
a window into these hitherto
invisible worlds...
436
00:49:25,120 --> 00:49:28,600
..and one of these is that
revealed by polarised light.
437
00:49:31,400 --> 00:49:34,920
It plays a crucial role
in the lives of many animals,
438
00:49:34,920 --> 00:49:38,960
including these small fiddler
crabs in Darwin, Australia.
439
00:49:44,360 --> 00:49:48,120
We worked with a team
of scientists to develop a unique
440
00:49:48,120 --> 00:49:52,840
and pioneering camera system
to reveal this hidden world.
441
00:49:52,840 --> 00:49:54,240
100% here.
442
00:49:55,640 --> 00:49:58,880
The camera detects
areas of polarisation,
443
00:49:58,880 --> 00:50:02,520
such as the light that passes
through polarising sunglasses.
444
00:50:02,520 --> 00:50:05,160
Put it to 100% here.
445
00:50:05,160 --> 00:50:08,840
It then combines vertical
and horizontal polarisation
446
00:50:08,840 --> 00:50:13,000
to show the contrast between
polarised and unpolarised light.
447
00:50:15,160 --> 00:50:19,480
With this new camera, the team
hope to find out how fiddler crabs
448
00:50:19,480 --> 00:50:22,440
use polarised light to signal
to each other.
449
00:50:24,720 --> 00:50:27,960
But this camera had been
developed in sterile, controlled
450
00:50:27,960 --> 00:50:32,000
conditions, and these fiddler crabs
live in one of the least sterile
451
00:50:32,000 --> 00:50:36,000
environments on Earth -
Australia's tropical mudflats.
452
00:50:38,800 --> 00:50:42,560
Quite a challenge for the cameraman,
Mark Lamble.
453
00:50:42,560 --> 00:50:46,800
That mudflat - it's just a really
extreme environment to work.
454
00:50:46,800 --> 00:50:51,880
Blazing sun overhead, really high
humidity and almost no airflow.
455
00:50:55,360 --> 00:50:57,000
The camera needed to be
456
00:50:57,000 --> 00:51:01,240
half-buried in mud to get
a fiddler crab's eye view.
457
00:51:02,880 --> 00:51:05,880
Whether the camera would work here,
no-one could be sure.
458
00:51:07,320 --> 00:51:09,160
I'm slightly worried.
459
00:51:09,160 --> 00:51:11,960
Hopefully, we are not going to miss
that special moment
460
00:51:11,960 --> 00:51:15,480
as the camera is not going to work,
but I think we'll be OK.
461
00:51:15,480 --> 00:51:17,080
Good luck. Thank you.
462
00:51:20,160 --> 00:51:23,560
Once in position, Mark settled
down for an uncomfortable wait.
463
00:51:27,680 --> 00:51:30,960
If the crabs detect
the slightest movement,
464
00:51:30,960 --> 00:51:33,280
they disappear into their burrows...
465
00:51:35,680 --> 00:51:36,760
..again...
466
00:51:38,520 --> 00:51:39,480
..and again.
467
00:51:42,280 --> 00:51:45,720
I have to be really still
or they will not come out at all.
468
00:51:46,880 --> 00:51:48,760
I'd love to be able to have
an umbrella over me,
469
00:51:48,760 --> 00:51:50,840
so anything higher than me
470
00:51:50,840 --> 00:51:55,920
is just not tolerated by the fiddler
crabs, they just won't come up.
471
00:51:55,920 --> 00:52:00,600
But amazingly, the camera survived
the heat, the humidity
472
00:52:00,600 --> 00:52:05,000
and the caustic brine, and
eventually Mark was able to capture,
473
00:52:05,000 --> 00:52:09,200
for the first time, a fiddler crab's
world in polarised light.
474
00:52:12,760 --> 00:52:16,800
Light reflected from the crabs'
bodies is unpolarised,
475
00:52:16,800 --> 00:52:17,880
so they look dark.
476
00:52:19,280 --> 00:52:22,120
This makes them
stand out against the mudflats,
477
00:52:22,120 --> 00:52:24,720
from which the reflected
light is polarised.
478
00:52:27,000 --> 00:52:30,440
They can see things that
we can only imagine.
479
00:52:30,440 --> 00:52:33,760
When you look up and you see a bird
fly over, it's a white bird against
480
00:52:33,760 --> 00:52:38,160
a white sky whereas, when they look
up, it's just this total silhouette
481
00:52:38,160 --> 00:52:42,840
with the polarisation, and they can
see birds coming from miles away,
482
00:52:42,840 --> 00:52:46,240
and often I'm filming and
they'll all bolt down their holes,
483
00:52:46,240 --> 00:52:48,040
and I'll wonder why they've done it,
484
00:52:48,040 --> 00:52:49,600
and it's just because
they've spotted
485
00:52:49,600 --> 00:52:52,320
a bird way earlier than I would
have been able to see it.
486
00:52:55,240 --> 00:52:58,960
So polarised light helps the crabs
pick out distant potential
487
00:52:58,960 --> 00:53:03,320
mates, rivals and predators more
quickly against their bright,
488
00:53:03,320 --> 00:53:07,000
polarised background.
And for Victor,
489
00:53:07,000 --> 00:53:10,240
it was the first time he had seen
the camera he had developed in
490
00:53:10,240 --> 00:53:15,720
the lab revealing the world in the
way these tiny creatures see it.
491
00:53:15,720 --> 00:53:19,280
It's amazing footage you've
captured, Mark. It's really amazing.
492
00:53:20,840 --> 00:53:23,840
You really put the system
to its limits today.
493
00:53:27,720 --> 00:53:31,360
But there was one even bigger
challenge for the camera -
494
00:53:31,360 --> 00:53:33,960
one that lay farther out to sea.
495
00:53:37,080 --> 00:53:40,760
Underwater, only crustaceans,
cephalopods
496
00:53:40,760 --> 00:53:45,680
and a few fish are known to be able
to see and react to polarised light.
497
00:53:47,000 --> 00:53:50,080
But there is one animal here
that exploits this ability
498
00:53:50,080 --> 00:53:55,840
in a really complex way -
the peacock mantis shrimp.
499
00:53:55,840 --> 00:53:59,760
It's not only able to detect
polarisation, but has patches
500
00:53:59,760 --> 00:54:04,080
on its body that reflect light
in a polarised form,
501
00:54:04,080 --> 00:54:07,520
and it uses them to signal
to others of their own kind
502
00:54:07,520 --> 00:54:10,080
in ways that we cannot normally see.
503
00:54:12,400 --> 00:54:15,680
Professor Justin Marshall
of Queensland University has
504
00:54:15,680 --> 00:54:19,760
adapted the polarising camera
to work underwater.
505
00:54:19,760 --> 00:54:21,120
So here we go, Rory.
506
00:54:21,120 --> 00:54:25,600
This is the camera that's
going to show us polarisation.
507
00:54:25,600 --> 00:54:28,640
Rory McGuinness,
the team's underwater cameraman,
508
00:54:28,640 --> 00:54:31,480
arrives to see the latest
version of the camera.
509
00:54:33,120 --> 00:54:35,320
So you've obviously done
a lot of work to get
510
00:54:35,320 --> 00:54:37,160
this into an underwater housing?
511
00:54:37,160 --> 00:54:38,280
Yep, that's right.
512
00:54:38,280 --> 00:54:42,120
So you can see in here there's
a computer that runs the camera.
513
00:54:42,120 --> 00:54:44,680
There's quite a lot of engineering
going on in there.
514
00:54:50,680 --> 00:54:55,680
Taking the camera for its first test
underwater was a tense moment.
515
00:54:55,680 --> 00:54:59,080
Computers and salt water
don't usually mix well.
516
00:55:07,640 --> 00:55:09,640
Having found a suitable spot,
517
00:55:09,640 --> 00:55:12,720
it was time for the camera's
first critical test.
518
00:55:17,600 --> 00:55:19,640
A leak could be disastrous...
519
00:55:24,080 --> 00:55:25,920
..but all is well.
520
00:55:25,920 --> 00:55:28,160
Now they need a mantis shrimp.
521
00:55:28,160 --> 00:55:31,280
Looks like a promising area, Justin.
522
00:55:31,280 --> 00:55:33,040
It looks perfect, Rory.
523
00:55:33,040 --> 00:55:37,480
So we're looking for a hole
with coral around it.
524
00:55:40,320 --> 00:55:44,640
Hey, look!
Is that a mantis shrimp hole?
525
00:55:44,640 --> 00:55:47,200
The hole's resident soon appeared.
526
00:55:47,200 --> 00:55:49,800
It was time for the camera
to show what it could do.
527
00:55:51,720 --> 00:55:55,800
As the shrimp turns, the polarised
camera shows that its tail
528
00:55:55,800 --> 00:56:00,000
has a shimmering fringe -
invisible in normal light.
529
00:56:00,000 --> 00:56:03,280
Look at that. That's extraordinary!
530
00:56:03,280 --> 00:56:05,120
Life in polarised light.
531
00:56:06,560 --> 00:56:08,360
And this is the first time...
532
00:56:10,840 --> 00:56:14,840
..we've been able to do this
with this very special camera.
533
00:56:16,920 --> 00:56:20,680
The light on the ocean
floor is unpolarised.
534
00:56:20,680 --> 00:56:23,800
So, in complete reverse
to the fiddler crabs,
535
00:56:23,800 --> 00:56:26,840
the mantis shrimps use
polarisation to stand out
536
00:56:26,840 --> 00:56:29,320
against the unpolarised background.
537
00:56:33,800 --> 00:56:39,080
Special pigments polarise the light
reflected from parts of their body,
538
00:56:39,080 --> 00:56:43,560
allowing them to signal to deter
intruders and attract mates.
539
00:56:49,240 --> 00:56:53,880
This camera has revealed to us a
first glimpse into a world of light
540
00:56:53,880 --> 00:56:57,360
that we're only beginning to be
aware of, let alone understand.
541
00:57:06,320 --> 00:57:09,960
In the next episode,
the story of Life In Colour
542
00:57:09,960 --> 00:57:13,280
continues where the
stakes are even higher
543
00:57:13,280 --> 00:57:15,760
and colour is the key to survival.
544
00:57:17,680 --> 00:57:22,320
We discover how animals use
colour to hide from predators
545
00:57:22,320 --> 00:57:24,280
and from their prey.
46430
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