Africa

In the four years of making this series,

we've been to some astonishing places

and seen animals behaving in ways that have never been filmed before.

In this program we travel to the four corners of Africa.

From the jungles in the west to the mountains of the east.

From the ancient south to the deserts of the north.

Revealing extraordinary landscapes.

Looking at them through the eyes of the animals that live here.

The continent's wildlife is the most celebrated on earth.

But it still has plenty of surprises.

We start in the most ancient corner of the continent.

The Kalahari in Africa's south-west.

The land of great thirst.

And also a land of great emptiness.

Water and food is hard to find.

Only the resourceful and resilient can survive here.

Amongst the sand, scrub and salt pans, there is water if you know where to look.

In a few exceptional places, water wells up

almost miraculously from deep underground.

It's so rare, it draws animals like a magnet.

A black rhinoceros.

The Kalahari's most cantankerous resident.

They certainly don't like sharing a water hole with lions.

But under the cover of darkness.

At one secret and very special water hole.

Rhino abandon their normally solitary life.

And come from all around to meet under the stars.

This young female seems nervous.

She senses other rhinos close by.

A mother appears from the shadows with her calf.

Tentatively, they greet one another.

They may be ill-tempered by day, but now they become gentle and affectionate.

More and more arrive.

The female is excited about something.

Or someone.

Here comes a really big male.

Who would have thought that rhino could be so flirtatious?

A different male tries to come between them.

Somehow or other, he's got a pair of antelope horns stuck on his nose.

It looks as if she's been won over by his eccentric style.

He leads her off, away from the party.

He may have style, but he's turning out to be something of a disappointment.

A girl can only put up with so much.

The only way she can get rid of him is to pretend she's asleep.

To see so many rhino in one place is a revelation.

And that's the power water has here.

The power to bring together the greatest gathering of rhinos anywhere on Earth.

Springbok have been roaming this desert for many months,

searching not for a water hole,

but for one of these rare and highly localized downpours.

Grass is sprouting for the first time in months.

Food at last.

And that is worth celebrating.

If you're a springbok, that means pronking.

We still don't know exactly why they do this.

The simplest answer is that they're dancing for joy.

Water has left its imprint on the land.

It once flowed here.

But now, the Hoanib, one of Namibia's rivers, is a river of sand.

It's home to this bull desert giraffe.

The trees that line these sand rivers send roots down over

30 metres to tap water that lies deep beneath the riverbed.

Even on tiptoe, he still needs a half-metre-long

tongue to reach the leaves he so badly needs.

He's ruled this stretch of the Hoanib for over a decade.

And this prime territory is attracting females.

He waits confidently for her.

But they've got company.

A young male.

The old bull won't tolerate a rival.

Pushing and shoving, they size each other up.

The young rival seems to think he has a chance and attacks.

The first few blows usually settle things in such battles.

But here, the stakes are high.

Neither will back down.

The young male aims for the rump.

The old bull... Targets his rival's legs.

The old bull is down.

Is this the end of his reign?

He knows a knockout blow is coming.

But the old bull ducks.

And strikes a blow to his rival's underbelly.

Out for the count.

The old bull is victorious.

But only just.

The sand river remains his to rule.

It's a river that is about to be transformed.

Under clear blue skies, water floods down the Hoanib.

The welcome consequence of rain that fell hundreds of kilometers away.

The water may only flow for a matter of hours.

But this miraculous flood is enough to provide a lifeline

for the trees and the giraffes of the Hoanib River.

It's what makes this place worth fighting for.

Rare water holes, occasional downpours and short-lived rivers provide just enough

water to get by in this, the most ancient corner of Africa.

The journey up the coast towards the equator and the vast Congo jungle meets

the sand, surf and fresh sea air of the Atlantic Ocean.

Spray blows in from the sea, making the grass salty

and enticing rarely seen animals to come out of the forest.

But this is not their home.

These animals belong inside the tropical rainforest that cloaks Africa's center.

The jungle is not an easy place to carve out a living.

Creatures are locked in a battle for food, space and light.

And more than anywhere, the landscape itself seems alive.

It's a crowded, tangled place.

Only forest elephants can clear pathways through the forest.

They have a need to socialize.

And in the Congo, there is a special place where they can meet and mingle.

A place that the elephants have created for themselves.

And this is it.

Dzanga Bai, the legendary village of elephants.

As well as being a place where they can enjoy one another's

company, this great clearing satisfies another craving...

for salts.

The salts lie deep under the mud, so the elephants must mine for them.

Dawn reveals the arrival of new visitors.

including this young bull elephant.

He is in a state of musth.

A kind of sexual fury.

But will throwing his weight about impress the females?

The cows only become fertile once every two years,

so opportunities to encounter one at the right time are not common.

This could well be the first chance this young male has had.

And there are no older bulls around to put him in his place.

Just for a moment, he is king of the Bai.

But his rule doesn't last for long.

Enter another lusty bull.

And a much bigger one.

But the young bull is still charged up with testosterone.

Bold or foolish, he's going into battle.

He never really had a chance.

Dzanga Bai is a huge clearing,

but it's still just a speck in this vast expanse of green.

Each hectare of forest produces, as vapour,

almost 190,000 litres of water a year.

So much that it creates its own weather.

Each year, as many as 100 million lightning bolts strike over the forest.

That's more than anywhere else in the world.

And with the lightning comes the rain.

It's certainly perfect weather for frogs.

The big storm is the cue for the most important climb of this frog's life.

It's a male in search of a mate.

But if he is to find one, he has to get to the top.

He needs to keep his wits about him,

for the rain also brings out hunters.

Easy does it.

The top at last.

But he's late to the party.

The higher a male sits, the further his voice will carry.

So the top slots are worth fighting for.

And he's won.

He has the top place.

So now it's time to sing.

And a white-bellied female responds.

They join together to mate.

The loser will have to wait for the next storm before he sings again.

She lays her eggs on a blade of a long leaf.

And he, using his back legs, folds it over and glues its two edges together,

shutting the eggs inside.

This sealed nest is the safest place these leaf-folding

frogs can find to protect their precious brood.

Within days, the eggs are developing.

The timing is perfect.

The rain washes away the glue.

And the tadpoles slip out of the leaves into the growing puddles below.

The forest once stretched unbroken from the west

coast of Africa all the way to the Indian Ocean.

But as we travel east, the scene is very different.

The forests now give way to frozen summits.

Up here lies the largest glacier in Africa,

only a few miles north of the equator.

These, the Ruwenzori, form part of a massive barrier.