Madagascar

60 million years ago,

on the shores of this tropical island, an extraordinary story began.

The waves brought ashore an odd band of survivors,

a few ancient creatures

that had been accidentally swept across hundreds of miles of ocean

from a distant land.

They found themselves here, in a place unlike any other.

Totally cut off from the rest of the world,

these castaways made this island their own,

gradually evolving into a collection of wildlife

that's strange, rare, and utterly unique.

So rare, that more than 80%

of the species are found nowhere else on Earth.

The island was Madagascar.

This is the story of what happens when a set of animals and plants

are cast away on an island for millions of years.

This is how this curious wonderland came into being.

It had all begun millions of years earlier,

when a great slab of land broke apart

to form the continents as we know them today.

Africa went one way, and India went the other.

And an orphan chip of land was cast adrift

and ended up hundreds of miles from the nearest land.

Its unusual geological history,

its isolation, and its resting place in the tropics

were to shape Madagascar's fortunes.

It's the world's oldest island.

And it's had time to develop an astonishing range of landscapes.

It's split in two by a spine of mountains

that runs its entire length and each side has its own character.

On the western side, lie huge forests, populated with strange, bulging trees.

Further south, an alien world,

a parched and sandy wilderness with an immense lake of salt,

and gnarled and twisted spiny woodlands.

And on the eastern side, lush jungle drenched in rain.

It's this combination of long isolation and varied landscapes

that's created the eccentric diversity of wildlife

which makes this island so special.

These rainforests are unlike any other rainforest on Earth.

And they're home to Madagascar's most successful inhabitants.

They're lemurs.

There are 80 different types,

from nocturnal, mouse-size creatures,

to this, the biggest, the size of a child.

It's an indri.

They are direct descendants of those first primitive mammals

that had washed in from Africa by chance.

And now, they live nowhere else.

They have almost dog-like faces, but they're primates, related to us.

And when you watch them, you can see it.

They're highly social.

At two years old, this young male is an adolescent,

but he's still close to his mother.

H is little sister is just six months old.

This family group will stay together for several more years.

Lemurs also have the grasping hands and feet of all primates.

It's fundamental for a life in the trees,

as well as an effective way to put a stranglehold

on an older brother.

For an indri, childhood is long.

It's nine years before they're fully adult.

There's plenty of time for play

and perfecting their impressive jumping skills.

And, perhaps, even a spot of showing off.

Everywhere you look, Madagascar has echoes of elsewhere.

At first glance, similar but with different origins.

On the rainforest floor,

an animal emerges that might be mistaken for a hedgehog.

But she's only the most distant relation.

She's a tenrec, another of Madagascar's own inventions.

And these are her youngsters.

Dozens of them.

Tenrecs have the distinction of giving birth

to more babies than any other mammal on Earth,

as many as 32 .

Her babies are stripy,

the better to hide in the shadows of the rainforest floor.

Their ancestor, too, had washed in from Africa.

And, like the lemurs, they've diversified into many different species.

As well as being Madagascar's equivalent of hedgehogs,

tenrecs also take the place that moles and shrews

would occupy anywhere else in the world.

Madagascar's rich forests

have been isolated from outside influence for so long,

they have become an evolutionary cauldron,

producing increasingly extreme forms of life.

And none are stranger than this.

It's a giraffe-necked weevil.

And this is a male.

And this is the reason for his extra long neck.

He uses it for fighting.

Meanwhile, a female weevil, who's not quite as long-necked,

is beginning an ambitious construction project.

She's snipping through the leaf's veins

and making little creases in it.

She also appears to referee the fight.

She finally mates with the winner.

Then, using her powerful legs,

the female starts to fold the leaf in half.

She then curls up the end.

And inside the curl, she lays a single egg.

All around the rainforest edge,

females are busy rolling and curling their leaf nests.

Each seems to have her own design.

Only in these particular rainforests,

and only on this one particular type of soft leaf,

are conditions right for her to make her nest.

It's an astonishingly specific behaviour.

The expectant fathers are apparently just getting in the way.

But they may be guarding against tiny insects

that would parasitise the newly-laid egg.

The female has bitten tiny notches along the leaf's ribs

to form a kind of Velcro strip, to help it all stick together.

A few final folds and the nest is complete.

When she finally snips the leaf-roll off,

it falls to the forest floor to hatch.

All that effort, for just one egg.

Madagascar has had a turbulent past.

At its birth, it was ripped from India and Africa,

and the geological upheavals have continued since.

The north of the island is speckled with slumbering volcanoes.

On the forested slopes, lives another Madagascar speciality,

a chameleon.

Chameleons weren't amongst those pioneering castaways.

Theirs is a different story.

It's thought that they evolved here, in Madagascar itself.

They're wonderfully adapted to a life in the trees.

Their toes are fused, so their feet grip like tongs.

And the arrangement of their legs is unusual for a reptile.

They're beneath their body.

This allows them to walk on branches thinner than their body.

A male panther chameleon, one of the biggest.

A second male is in his tree.

He won't like that.

If the intruder doesn't back down, there will be trouble.

They're evenly matched, it's neck-and-neck.

The territory holder wins,

and the loser takes the quickest way out.

In these isolated forests,

chameleons have taken a variety of paths

and have diversified to an astonishing degree.

Some are miniatures and have the rich forest floors to themselves.

A pygmy chameleon, the world's tiniest reptile,

tiptoes through the leaf litter on the steep volcanic slopes.

She's so tiny, she's scarcely bigger than an ant.

And over here, in a forest of toadstools, a male.

He's looking for her.

He's even smaller than she is.

Finding a mate in a giant world is challenging.

And it's somewhat hazardous,

when you could get run over by a millipede!

It takes a while, but when he finally reaches her,

he has a special tactic.

He's not going to let go.

They're not mating, simply riding around

until the time is right.

He barely touches her, just an occasional gentle, little sway.

They can go round like this for days.

But at least they won't lose each other

in their big volcanic forest.

The heart of Madagascar still rumbles with geological activity.

The centre of the island is a wide plateau of uplifted rock.

Here, there are still thousands of earthquakes every year.

Over eons of time, millions of these tiny earthquakes

have torn a vast hole right in these central uplands

forming this, Madagascar's biggest lake,

Lac Alaotra.

Around the edges of this massive body of water,

there are reed beds.

But the vegetation is not fixed,

it floats in great mats in water three metres deep.

It's tricky and inaccessible to most.

But one creature has adapted to live here, and only here.

This is the Lac Alaotra reed lemur.

Not only is it small enough to climb the thinnest reeds,

it can also survive on a diet of tough grass.

Unusually for a primate, it lives its whole life over water.

And it only lives on this one lake.

This family group has a patch of reeds to themselves.

But they have a problem.

To find enough to eat, you have to move from reed bed to reed bed.

And that takes skill and practice.

These lemurs can swim, but they prefer not to.

So they have developed a special technique

for crossing the reed beds without ending up in the water below.

Their mother is an old hand.

Even with a baby on her back, she's sure-footed.

And her older children are getting the hang of it.

These lemurs are so specialised,

that they would struggle to live anywhere else.

While Madagascar's centre was shaped by volcanic fire,

the western side of the island has an entirely different story.

For millions of years this landscape was drowned,

and layers of limestone formed underwater.

When the ocean finally retreated, this is what was left.

It's a gigantic, ancient reef.

The seabed was pushed up, creating a great block of limestone.

Over time, it's been carved by water into forests of giant pinnacles.

This is the Tsingy,

one of Madagascar's strangest landscapes.