Planet Earth III

This is Guelta d'Archei in Central Africa.

A hostile, seemingly empty world.

There is life here.

But it exists at the very limits of survival.

For this is a world with almost no water.

Lands like these cover over a third of our planet.

Here, life is forced to do things differently.

This is the most ancient desert of all.

The Namib - in south west Africa.

It is one of the hottest places on Earth.

Yet this male ostrich and his mate

have come here to start a family.

Few predators venture out during the heat of day.

But such safety comes at a price.

Out in the open, the newly-hatched chicks are exposed

to the crushing heat of the sun.

But not all of the brood have hatched.

Until they do, the family will stay here.

The adults take it in turns to protect the brood.

So whilst the female takes a well-earned break,

the male takes over for the most testing shift.

He gently rolls the unhatched eggs...

...calling to the young within them.

He doesn't want to leave anyone behind.

The temperature continues to rise by five degrees Celsius every hour.

He protects the chicks that have emerged...

...shading them with his own body.

At the end of another gruelling day in the sun...

...he's lost almost all his energy.

But he must resist the urge to rest.

The cool of the night brings some relief...

...but now predators are out and about.

It's going to be a long night.

Dawn brings a surprise.

Three additions to the family...

...to greet the returning female.

But there's a problem.

The chicks won't survive another day in these temperatures.

Yet the male is reluctant to leave.

Some of the eggs have still not hatched.

But time has run out.

They must depart.

Just a few minutes too late.

Alone and without the protection of its parents,

this hatchling's chances are slim.

HATCHLING CALLS

CALLING CONTINUES

Survival here, as in all deserts,

is on a knife edge.

So desert dwellers have had to evolve in remarkable ways.

Some have even given rise to legends of dragons and unicorns.

And even the dunes have their own magical quality.

Indeed some have their own voice.

Here in Arabia, this extraordinary sound

is created by billions of moving sand grains

vibrating against one another.

The eerie song they produce can be heard for miles

across the world's biggest sand desert.

Winds have also built sand into surreal shapes.

Deserts around the world can appear so alien,

that they seem to belong to another planet altogether.

Few more so than here in Australia.

Yet one little creature chooses this desert

to prepare for a most important event in its life.

A male spotted bowerbird.

For the last two months,

he has been busy in anticipation of brief rains...

That is when females will look for a mate.

So he's built a bower, a sort of theatre,

a stage on which he will dance with a female, if she is willing.

He decorates the entrance with piles of empty snail shells and bones.

How could any female resist?

The rains are due any day,

so it's his last chance for improvements.

You can never have too many shells.

But in his absence...

...a rival male drops by, to size up the competition...

...and cause trouble.

Wreck your neighbour's bower

and your own might look better.

And perhaps one of the best bits

would look good in his bower.

The owner is back.

And something isn't right.

Repairs are needed.

Still no sign of rain or females.

Undeterred, he continues his preparations.

Time to rehearse his courtship display.

But sadly he may only ever dance alone.

For the last three years, the rains have failed.

Without them,

the females won't mate.

They need the rains to provide food for their family.

Changes in the climate are affecting these birds,

just as they are affecting us.

A quarter of the world's people live in arid lands.

So we, too, have to deal with climate change.

Less rainfall and extended droughts allow deserts to grow.

And as they do, so does the likelihood

of one of nature's most intimidating events.

A dust storm.

A wall of dust up to a mile high,

travelling at almost 70mph.

Today these destructive storms are some of the most powerful ever seen.

Unstoppable, they can travel thousands of miles...

...overwhelming towns and cities across the world...

...in an instant.

It takes millennia for life to adapt to the extremes of deserts.

These baboons manage to survive

in one of the driest environments on Earth.

The Erongo region in Namibia.

Not a single drop of rain has fallen here for eight months.

Life here for these baboons is as hard as it gets.

And it's especially difficult

for this young female.

She has just given birth to her first baby.

She's desperate for water.

Without it, she can't produce milk.

The tiny of amount of moisture in her food

is simply not enough for both of them.

The troop must constantly search for water.

And they won't wait for her.

At last, one of the troop's scouts finds a tiny trickle on a rock face.

Relief!

But not for everyone.

The young mother will have to wait.

Access to the precious water is determined by rank.

She is so low in the pecking order...

...she might fail to get any drink at all.

Because jumping the queue

is severely punished.

It's risky, but she can't wait any longer.

A dangerous move.

But there's no match for a mother's determination.

This will be enough to keep her and her baby alive until rain falls.

Rain brings salvation not just to her and the troop,

but to the thirsty land.

When it does fall, it can transform a desert.

And turn it into one of Earth's most productive landscapes.

Grasslands.

They support the greatest concentrations of large animals

to be found anywhere on the planet.

Here nature is at its most spectacular.

This leopardess, believe it or not,

is ready to hunt at a moment's notice.

She is one of the few special leopards that have

learnt to hide in the tree tops,

and wait for their prey to come to them.

Without making a sound,

she gets into position.

Not this time.

And now her presence is known to all.

But leopards will go to astonishing lengths to succeed.

And some are more daring than others.

This leopard climbs up to a branch nine metres above the ground.

She's higher than the roof of a two-storey house.

Leopards have killed themselves jumping from these heights.

To succeed on these equatorial grasslands,

you must be adaptable and sometimes brave.

The Eurasian Steppe,

the largest grassland on earth.

It tests animals in a different way.

Here, the wind can blow at speeds of nearly 80mph.

And temperatures drop to below minus 30 degrees Celsius.

Yet one bizarre creature has evolved ways to survive in these extremes.

Saiga antelope.

Small but tough animals that lived alongside woolly mammoths.

The male's enormous nose both filters out the dust

and warms up the cold air before it reaches his lungs.

But at this time of year, it also serves a very different purpose.

It impresses the females.

And the bigger it is, the better.

This old male knows what it takes to hold their attention.

But they make him work for it.

And if that isn't effective...

...he has other ways of impressing them.

A bush - very majestic.

But when you are king of the steppe,

there's always someone waiting to claim your crown.

This young buck fancies his chances.

He aims to steal the king's harem.

The challenger charges, ready to do battle.

This could be a fight to the death.

70% of rutting males will die.

The older male eventually begins to gain the upper hand.

And with one final effort,

he drives the young rival away.

The king has kept his crown -

and his harem.

Only the strongest saigas can endure and succeed

in one of the harshest places on Earth.

But close to the equator, where there is constant warmth and water,

there are grasslands close to paradise.

This is the most bio-diverse grassland in the world...

...the Cerrado in Brazil.

Here there are thousands of species of both animals and plants

found nowhere else.

A rich and complex community that is kept in balance

by this ghostly creature.

A maned wolf.