The sun.
It creates the daily rhythm for life on Earth.
A player in almost every drama that unfolds across our planet.
Hour by hour, its exact position is critical.
For some, it brings moments of enormous opportunity.
For others, it can spell disaster.
All over the world, animals' lives are governed
by the sun's journey through the sky.
How they respond can make the difference between success
and failure,
life or death.
This is just an ordinary day
on our extraordinary planet.
It's just before sunset,
which, in a forested gorge in Africa,
means bedtime for this chimp family.
The littlest member of the troupe wants to stay up.
But Mum is no soft touch.
Leopards hunt after sunset
and a baby chimp would make an easy target.
By making their beds high above the ground,
the families keep out of harm's way.
Plus, it's a pretty comfy way to spend the night.
As the canopy darkens,
the whole family cuddle close together and drift off.
The sun has completed its daytime journey of 180 degrees in the sky.
Sunset is inevitable.
The darkness every bit as powerful a game-changer as the light.
Most animals have to live half their life without the sun.
But it's a risky time,
and the decisions they make through the next 12 hours of darkness will be critical.
It can take just two minutes for the sun to sink below the horizon.
A short time in which everything changes.
Light and heat ebb away.
Photosynthesis shuts down.
Many daytimers find it hard to see in this twilight.
They're vulnerable to predators.
So, all over the planet, animals find the safety of their beds...
as drowsy hormones flood back into their bodies.
But not everyone's quite ready to let the day go.
Above a limestone cave in Borneo,
a hawk, a day flyer,
has not yet flown to its roost.
What it's waiting for is just beginning to stir.
Inside the cave, a storm is brewing.
The beating wings of millions of wrinkle-lipped bats.
They use sound more than sight to navigate,
so leaving the cave before dark won't help them find food.
But there's just so many of them
that flying any later would cut into valuable feeding time.
By pushing out into this last, brief window of light,
they're taking a huge risk.
The hawk is just one of many that's ready for them.
Our eyes would struggle in this twilight.
But the hawk's eyes can pick out fast-moving objects
in the faintest glimmer of light.
It's a twilight battle of the senses,
sonar versus eyesight.
In the last moments before complete blackness,
eyesight still wins.
Across the ocean,
on the shores of the Pacific coastline,
another army is gathering.
But, unlike the bats, are waiting for complete dark.
Green turtles normally sleep at night.
But these are all mothers-to-be.
They're ready to lay eggs,
but will only do so in absolute darkness.
Waiting patiently in the shallows, they watch the skies darken.
Tropical nights arrive quickly...
and in this narrowest of twilight windows,
on the Australian sand flats,
a tiny sea dragon plucks up the courage to make his move.
He's spent his life so far hidden in perfect camouflage,
against the kelp and weed.
But, in the failing light, he swims out into the open.
He needs open water to woo this exquisite female...
into passing her eggs into his care.
Out beyond the weed, they're exposed.
Any minute now, it will be dark,
the night predators out in force.
But he can't rush her.
She won't give up her eggs...
until he's proved he's Mr Right.
He needs to stay cool,
turn on the charm...
and impress her,
with his dance moves.
He tries to mirror her every twist and turn.
The light is failing fast.
Fortunately, she likes what she sees.
And, in this stolen slice of twilight,
they've given their offspring the best chance of survival.
With eggs safely transferred,
they return to secret hiding places among the weeds.
As the last scattered rays from the sun disappear behind the horizon...
there is true dark.
And with it, the waking of the night-time world.
Ready to snatch the opportunities,
which even the blackest hours on Earth will bring.
This is the moment the turtles have been waiting for.
One mum ventures out of the water.
She's cumbersome on land.
An easy target for predators in the day.
But, with the light gone,
the coast is clear.
Each mother will spend hours digging and carefully laying up to 200 eggs.
And while the turtles bury their treasure on the sandy beach...
in the desert, a tiny hunter's gearing up for action.
This scorpion has spent the daylight hours hiding deep in crevices,
to avoid being eaten.
But when the sun is quite absent, she becomes the predator.
Her small eyes are all but useless in the darkness.
Instead, she senses prey through vibrations.
The movement of a single grain of sand
gives her all the information she needs to attack.
But just as she closes in on her first meal of the night,
she freezes.
Sensing danger.
Even in the dead of night,
our sun is still not lost.
Its rays pass by the dark side of the Earth...
and reflect off its moon.
A ghost sun.
The full moon rises high and bright...
and the scorpion begins to glow.
Ultraviolet light reacts with fluorescent chemicals in the scorpion's armour.
Her eyes can't see moonlight, but her whole body is a warning system,
telling her that her cover is blown.
She needs to hide, before a predator sees her.
So she uses the fluorescence to her advantage...
as a light sensor.
Any part of her armour in shadow will stop glowing...
telling her she's found safety.
In Africa...
a pride of lions are making their feelings about the full moon very clear.
A day spent sleeping in the shade has left them with empty stomachs.
The lionesses had been waiting for nightfall to hunt.
Their eyes, packed full of low-light receptors,
give them the upper hand on a dark night.
But tonight, the plains are floodlit...
ruining any chance of a surprise attack.
The cubs are hungry,
but their frustrated mums know it's not even worth their energy to try.
They'll just have to sit tight and wait for morning.
The full moon changes everything.
Many nocturnal species around the world will hide away...
and choose to go hungry,
rather than risk coming out under the reflected sunlight.
It's known as lunar phobia.
But to a hunter in Southeast Asia,
a bright-lit night is an opportunity to be seized.
Every night, the rainforest's insect population comes under attack
from a palm-sized primate.
Don't let the wide eyes fool you,
this family of spectral tarsiers are ruthless hunters.
With saucer-like eyes, each as big as their brain,
this family use the faintest of starlight
to see the forest in incredible detail.
And when your eyes are this sensitive,
all this reflected sunlight is a gift.
The family aren't about to miss a moment
of the best hunting night of the month.
In the moonlit forest, the family might triple their hunting success.
But it's all too easy for a tarsier
to have eyes bigger than its stomach.
In the early hours, full to bursting,
the family call it a night.
The moonlit world seems to exist only in blues and greys.
Its light robs colour of everything it touches.
But actually, this is all in the eye of the beholder.
The moon's rays are reflected sunlight,
with its whole spectrum of colour...
but without its power.
Moonlight is so dim,
the colour receptors in our eyes can barely function.
After sunset, the low-light receptors take over,
which can only make very basic colour judgements.
The world appears ghostly,
because our eyes are unable to see it any other way.
But not everyone sees the moonlit world with such a limited palette.
This tiny gecko's eyes are exceptional tools...
350 times more light-sensitive than our own...
able to interpret the whole spectrum of wavelengths arriving from the moon.
In the dead of night,
this miniature hunter sees the forest world in technicolor.
Although it's 500,000 times fainter than the sun...
when the light of a November full moon...
flickers through the waters off the coast of Australia...
it's still powerful enough to trigger a spectacular event.
There are over 1,000 species of coral in our world's oceans...
growing in reefs as colourful as any garden.
But their beauty disguises a secret wild side.
Most corals breed sexually.
Either by releasing eggs and sperm separately
and allowing the water to mix the two...
or by creating bundles of ready-mixed male and female cells.
If single corals were to spawn randomly,
the chances of mixing would be slim.
Most of the eggs would be gobbled up.
It makes most sense to spawn en masse.
But for that to happen, the corals need a cue.
So they wait for the November full moon to rise.
When the sun's reflected light his photo receptors on the corals...
it's like an aphrodisiac...
sending them into a frenzy.
Over the next few nights, over 500 different species of coral
will release together in perfect synchronisation.
But just why the November full moon excites these corals
more than any other
is still one of our planet's great mysteries.
While a new reef is conceived in Australia,
all over the world, the upper layers of the ocean have come alive.
The finishing line for the greatest daily migration on the planet.
These tiny animals are the bottom of the oceanic pecking order.
Food for thousands of species...
from enormous whales to miniscule shrimp.
They've spent the day hidden in the deep dark,
where they're safe from hungry mouths.
But there's very little food about.
They need to seize their chance to eat.
So, every night, the sunset fires the starting gun
for a desperate race to the surface...
where millions of hungry mouths feed on the day's growth of algae.
In the dark, deep ocean, plankton use light to communicate...
to ward off attackers and attract prey.
But gathered together on the surface in their millions,
this light illuminates the water.
A magical light display.
In fact, every night, as we turn on our lights...
all over the world, different species, from firefly...
to fungus...
use the dark as an opportunity to create their own light.
This cave glow worm is particularly devious...
spinning sparkling strands...
to mimic the stars in the sky.
An insect thinks it's made its break into the night air...
only to meet a sticky end.
It's midnight.
The furthest point from the sun.
From this moment, the moon will start its slow sink towards the horizon.
And back in Africa...
the lion pride's luck might just be about to change.
Clouds scudding across the night skies block the moon.
Blackout.
The grazing wildebeest and zebra are plunged into darkness.
And this lioness is ready to seize her opportunity.
She might have only seconds to strike.
She needs to get in close.
A midnight feast for the whole family.
We only have to look at the night sky
to know that not all stars are equal.
The larger the star, the hotter it can burn...
which is why the smallest stars look red in the night sky,
while the largest burn bright blue.
In the clear skies of northern Africa...
the magnificent pattern of light spilling from the Milky Way
is about to give a crucial steer
to a male dung beetle.
A ball this size doesn't just mean guaranteed food,
but the promise of fatherhood.
Enough dung to make a nursery for three pairs of tiny feet.
But he can't rest on his laurels just yet.
There are work-shy beetles about who would steal his ball rather than make their own.
He's got to get his ball far away from the dung pile
and out of the reach of thieves.
But working in the dark, he's in a fix.
If he stops here, he risks his ball being hijacked.
If he rolls it around aimlessly,
he could just end up where he started.
On top of the dung ball, he looks for all the world
as if he were weighing up his options.
But in fact,
this beetle is looking to the heavens for guidance.
His eyes are not powerful enough to make out single stars.
But scientists believe that dung beetles can
and use them to orientate themselves.
Decision made, he repositions himself and sets off.
Incredibly,
the celestial highway provides this tiny star-gazer with a map in the dark.
For the first few hours after dark,
the heat absorbed during the day radiates back into the atmosphere.
But it's a limited supply.
By the early hours, it's run out.
And the temperature has plummeted...
putting three brand-new lives in danger.
On a riverbank in India, these tiny gharials, fish-eating crocodiles
have just hatched, into the darkness.
They're cold-blooded.
Just digging their way out of the sand has used up most of their energy.
Their first night could be their last,
if they don't warm up fast.
Luckily, their mum knows just where to lead them.
This pool has absorbed a whole day's worth of Indian summer sun...
and has retained the heat far longer than the land.
So, while the riverbank cools right down,
the newborns remain snug...
incubated until sunrise, when they can begin looking for their first meal.
But the coldest hours don't always bring the potential for disaster.
In the forest of New Zealand, love is in the cold, dark air.
The kacapo is a real one-off.
The world's only flightless, nocturnal parrot.
While the rest of the parrot community sleeps,
he strolls the forest floor.
There are less than 150 kakapos left in the wild,
which can make finding a mate unusually difficult.
And tonight, he's looking for some female company.
So he uses the coldest part of the night to boost his chances.
It may not be the most beautiful love song,
but it's effective.
The low-frequency sound waves are amplified in the cold air.
If there's a female in the area, she's bound to hear it.
And he'll keep booming until she's by his side.
The coldest, darkest hours of the early morning
are the least productive for life on Earth.
Most of us have shut up shop and are eagerly awaiting for sunrise.
But the elephant yam,
known locally as, "The witch in the forest,"
takes advantage of this gap in the market
and opens for business.
In the dark, a bright flower counts for nothing.
Instead, the witch uses dark arts to attract
and keep its customers.
In the cold air, it secretes a scent...
not a perfume, but a stench of rotting flesh.
Smells don't carry well at night.
The air is too cold and still.
But the witch can generate its own heat,
which it uses to waft the smell far into the night air.
Irresistible, if you're a carrion beetle.
Zoning in on what they think is a warm, decomposing meal...
the beetles discover they've been tricked.
But it's too late.
The witch won't release her prisoner tonight.
She'll wait until dark tomorrow.
Covered in her pollen,
the beetle will be allowed to escape...
just as another witch blooms and casts the same wicked spell.
It's nearly morning.
The moon is hanging just above the horizon.
Soon, it will be overwhelmed by the first light of dawn.
But in the Arctic, the sun is casting
a new and different power over the last few hours of darkness.
Particles thrown from the sun's surface...
across 90 million miles of empty space, to reach the Earth.
They are directed by the Earth's magnetic field to the poles.
This cosmic storm creates a magical aurora.
The spectacular Northern Lights.
But behind this beautiful light show...
is a sinister force...
that impacts on whales, with potentially lethal consequences.
This humpback family are three-quarters of the way through an epic migration...
to reach feeding grounds off the coast of Alaska.
They're relying on the Earth's magnetism to chart their night-time course.
But the Earth's magnetism is becoming distorted under this barrage of energy.
It's believed whales can become disorientated.
Thrown off course.
They might even strand onto the land.
But soon, it will be morning,
and the sun compass will bring them back on track.
Dawn.
The very first light of a new day.
The sun's power will soon be felt...
and the world is waking...
ready to begin another ordinary day...
on our extraordinary planet.