Madagascar

A monsoon storm on the coast of an island in the Indian Ocean.

But this is not a normal tropical island.

This is Madagascar.

Once joined to Africa, Madagascar has been isolated for millions of years,

and it has evolved a set of wildlife all its own.

More than 80% of it is found nowhere else on earth.

This strange island is split in two by a line of mountains running its length.

The eastern slopes are drenched with rain and cloaked in jungle.

But cross these mountains into the western side, and you are in another world.

To live here, you need to cope with a landscape that is bone dry for most of the year.

A land where rain is fleeting and quite unpredictable.

And yet Madagascar's arid lands are full of life.

Everything that lives here has its own fight for survival and resources as the seasons swing by.

In this eccentric land, some of the strategies wildlife has developed are quite extraordinary.

Madagascar is a vast island.

A thousand miles from north to south, it is so big it has the variations in climate of a continent.

The mountainous spine down its length is a barrier to rain.

The land to the west is in a rain shadow.

And the further south you go, the drier it gets.

This is a journey through Madagascar's most challenging season,

the great drought that grips the south and west of the island for more than nine months of every year.

To survive these months, you need to be tough and ingenious.

And Madagascar's wildlife is certainly both.

Rising up from the southern flatlands is a strange, Grand Canyon-like landscape...

a great plateau of sandstone beaten down by millions of years of erosion.

It's August. Deep inland, far from the sea, it's searingly hot.

And it hasn't rained for months.

But it's not entirely dry here.

In deep, dark canyons there are slashes of green.

These lush forests are leafy all year, thanks to a constant source of water.

The very depth of the canyon shades it from the sun and keeps it permanently moist.

It's a rare oasis in an otherwise parched land, and it's a great attraction for wildlife.

A dragonfly patrols a patch of stream.

He's jealously guarding his precious territory,

pushing out male rivals while he waits for the females to visit.

And in this fortunate place lives a small family of lemurs Verreaux's sifakas.

They spent the chilly night in high rocky caverns, safe from predators.

At dawn, they move down into the canyon, stopping to warm up in the first rays of the sun.

And there's another member of the family.

A daughter, just a couple of weeks old.

She has been able to grip her mother's fur unaided since she was born, and just as well...

.. because her mother crosses the canyon with vast leaps, as much as nine metres in a single bound.

There is no shortage of food here for these vegetarian lemurs.

But for now, the baby is totally reliant on milk.

It will be another six months before she's completely independent.

Like all lemurs, sifakas are primates, and their social bonds are strong.

She will stay with her family in this vast canyon for the rest of her life.

These lush canyons are a rare leafy oasis.

The further south you go, the drier it gets.

There are rivers here in the deep south, but they are highly seasonal.

As the dry season takes hold, they run flat and broad...

ankle-deep streams on a bed of sand.

But the rivers carry just enough water and nutrients for ribbons of forest to grow.

And the masters of these river forests are these.

Ringtailed lemurs.

In gangs of 15 strong, they have the run of the place.

And it's the females who are in charge.

With the burden of raising young, they must have access to the best food.

These lemurs are protective of their patch.

Scent marking makes it clear to other gangs where the border lies.

As a group, they need to keep hold of their home territory.

LEMURS WAIL AND SCREECH

Intruders are seen off promptly.

Green as this river forest looks, at this time of year there is only

just enough food to go round, and these females all have babies to feed.

They all gave birth at around the same time.

By the time the rains return, the forest will be full of fruit,

and that is just when the babies will be old enough to feed for themselves.

It's a crucial adaptation to suit a place so driven by seasonal change.

Motherhood is taking its toll...

they are thin, and their fur is less than sleek.

But the dry season will eventually pass

and at least their forest is green all year.

Further to the west is a swathe of forest that is much more demanding.

It swings dramatically between wetness and desiccation.

For most of the year, it is cracklingly dry.

The most distinctive trees of these western dry forests are the Baobabs.

Their trunks are huge and bulbous, the better to store water.

They live for hundreds of years.

A tree like this will have seen many dry seasons pass.

It's now October, the height of the dry season, and it will be months before any significant rain falls.

For everything that lives here, it's a test of endurance.

Water is in short supply,

just a few little temporary pools dotted between the trees.

Everything must come here to drink.

And that's risky. Their predators will know where they are.

Brown lemurs creep timidly around the waterhole.

With very little fresh greenery to eat, they must drink every day or risk death from dehydration.

But every step on the carpet of dry leaves could reveal their presence.

At this time of year, they have babies too.

They're an easy target.

But this hawk is only after water,

a drink and a bathe.

In such tough times, there are battles for territory in the most unexpected places.

As night falls in the Baobab forest, an extraordinary crowd emerges.

They are baby flatid bugs.

By day they are barely visible, but at night they swarm over the trees and start to feed.

They drink sap, and each settles itself into a spot on the branch.

But even at this miniature level, there's a battle for resources,

and here and there fist-fights break out.

This curious spat has never been observed before.

For the most part, however, they feed quietly.

And as they feed, they excrete unwanted liquid, called honeydew.

It coats the branches and remaining leaves.

And this is very attractive to other insects that are out and about at night.

And that, in turn, provides a feast for mouse lemurs.

At around 60 grams, mouse lemurs are the world's smallest primates.

These are all males.

The females are fast asleep in tree holes, and have been for months.

They can sleep right through the dry season, and they'll only emerge when the rains come.

It's a way of saving energy.

So for now, the males are on their own,

feeding on anything that will take them through the lean times,

and waiting for the day that the females awake.

But of all Madagascar's southern habitats, none seems more challenging than this.

This is the far south of the island, where there is little standing water.

Rain is rare, and some years doesn't fall at all.

The sandy, porous rock drains quickly.

The forest that grows here is one of the strangest on earth.

It's called the spiny forest, for good reason.

There is nothing like it anywhere else in the world.

The plants are viciously spiny...

the spines collecting what little water there is in the air, and draining it back to the tree itself.

These plants are seriously odd...

with twisted, sprawling branches, these are octopus trees.

And euphorbias, looking like strings of sausages.

They barely even bother with leaves...

they photosynthesise through the green of their stems.

These are among the world's toughest plants.

It would seem there is nothing edible here...

what leaves there are are small, the better to avoid water loss,

and tucked down among the spines.

This place looks totally hostile.

But here too live ghostly little lemurs.

Verreaux's sifakas are among the hardiest of all the lemurs.

And they are quite at home here too.

They are perfectly adapted to this desiccated place, because they can go without drinking at all.

They get all the moisture they need from these unappetising looking leaves,

which they pick from between the spines.

They even relish the euphorbia fruit, apparently not bothered by the fact that these trees are dripping with

chemicals so strong they'd burn your skin.

And they too have babies,

born at what looks like the very worst time of the year.

Life here seems generally much more challenging.

Not only is there little to eat, these sifakas have to cope with

jumping between thorns that would go through your fingers.

It's hardly surprising that only half of sifaka babies make it to adulthood.

Within just a few months, these babies will have to

take the plunge and learn how to jump all by themselves.

For now, they cling to their mother and discover what's edible.

Back in the central canyon lands, the weeks pass. It's November, and there is still no rain.

There hasn't been for eight months.

The grassy plains are dry, but inside the canyon, thanks to the constantly flowing spring,

it is still almost ludicrously luxuriant and full of life.

Ringtails, the most adaptable of all lemurs,

have found a home here too.

They are the most widespread of lemurs, and they live all over the south of the island.

And here they seem to have found a life of ease.

They are able to take advantage of a range of food as it becomes available.

They'll eat leaves, flowers and even insects.

In an unpredictable place like Madagascar, that has helped them to thrive.

The babies are growing up.

Born at roughly the same time, every ringtail baby in the south is now about two months old.

And this young male is starting to find his way around this bountiful place.

But it will be a while before he's totally competent as a climber.

He won't even be fully weaned for another three months.

Although there is moisture in the leaves they eat, the ringtails can't go more than a day without drinking.

But finding water is not difficult here.

The stream never runs dry.

Outside the canyon, however, the grass is tinder dry.

Fire has been a factor here for millions of years.

The grass burns rapidly, and the fire spreads quickly.

These spots of flame and smoke flush insects from the grass,

so they are a huge attraction for kites and kestrels.

Back in the Baobab forest in the far west, it seems as parched as ever.

But now, in late November, there are signs that things are about to change.

The Baobabs' scrappy branches suddenly begin to put out a first flush of green leaves.

They are drawing on the precious water they've stored in their fat trunks.

There will soon be rain here, and the Baobabs sense that it's coming.

There is a scent of rain in the air.

Other life is beginning to stir.

This little chameleon has not long hatched

but already it's in a race.

And it has one of the strangest strategies of all for dealing with the extreme dryness.

They are Labord's chameleons, and they only live in this part of the island.

This little male already has a voracious appetite...

although this spider may be beyond him.

These strange little chameleons have the shortest lifecycle of any land vertebrate in the world.

They spent the last nine months underground, inside an egg,

and now they have just eight weeks to grow to adult size.

They will have to grow more than a centimetre a week.

There is no time to waste.

Conditions are so tough that living fast is the best strategy.

By the time the rains begin, his life will be almost over.

In fact the rains have already started...

only a splash, but a sign of a deluge to come.

For now, it's barely enough to wet the ground,

but it's enough to bring the mouse lemur females out of hibernation.

And the males are getting themselves ready for them.

They only have one chance to mate during the entire year.