Original subtitles

The great plains of Brazil are one of South America's best kept secrets.

Strange creatures walk in a sea of grass the outside world hardly knows.

Theirs is a land of extremes

dominated by the fiercest elements of nature.

For half the year it's tinder dry and ravaged by fire.

For the other six months it's drenched by torrential rain.

And there's another side to this secret land.

Huge torrents of water cascade off the grassland plain in a deluge

so mighty it creates the greatest expanse of seasonal swamp on earth.

This is a vast wetland that teems with wildlife.

The huge swamps and the high grasslands

are the two extraordinary faces of South America's Great Plains.

The swamp is called the Pantanal

a wetland the size of England and Wales combined.

The grassy plateau surrounding it is the Cerrado.

It's as big as the whole of Western Europe

although 60% is now ranchland and farms.

The last remnants of the Cerrado's grassland

have their own unique animals.

This may look like a fox on stilts

but it's actually a maned wolf.

The wolf is the largest predator on the open plains

but what it hunts is tiny.

Finding it is like looking for a needle in a haystack.

Massive ears help it pinpoint its prey.

And this is what it's after a little mouse.

The wolf stamps on the ground to try and panic it into running.

If the mouse so much as moves a whisker

it'll blow its cover.

For an animal this big a mouse is just a mouthful.

This high plains drifter has to keep on the move

if it's to find enough to eat

like everything else that hunts here.

If this were Africa

the plains would be thick with wildebeest

antelope and zebra.

The Cerrado seems empty even lifeless.

So what's eating all the grass?

There are grazers here countless millions

but they're hidden.

Only the turrets of their subterranean castles give them away.

Termites.

These tiny insects are the force that drives the grassland.

What they lack in size

they more than make up for in sheer numbers.

At the centre of each colony there's a gigantic queen.

She can turn out thirty thousand eggs a day.

Most eggs hatch into workers

but some will be soldiers armed with massive jaws

or chemical sprays.

And the colony needs an army.

Termites are edible and this much food doesn't go unnoticed.

But how do predators breach the defences of a termite mound?

Each has its own technique.

Anteaters tear a narrow gash in the wall with powerful claws

just big enough to admit a long sticky tongue.

There are two species here the giant

and this one, the collared anteater.

Armadillos rely more on brute force.

Their tongues aren't so long

so they literally bulldoze their way in.

Termites play a vital role as recyclers on the Great Plains.

In the cool of the night

they leave their mounds and collect dry grass

and leaves to eat.

The nutrients are then returned to the soil

in their droppings.

A termite colony is like a production line

converting dead grass into fertiliser and more termites.

The factory has its own built in air conditioning.

In the heart of the mound

it's constantly cool and moist

even when the world outside is sweltering in the heat.

Towards the end of the dry season

temperatures climb to nearly forty degrees.

For six months of each year there is no rain.

As a result these plains are treeless.

There's not a scrap of shade.

For the wolf and the flightless rheas

there's no escape from the sun.

The wolf is no threat

perhaps tempers are just a little frayed in the heat.

The sun sucks the last trace of moisture from the grass.

Far to the south-west

even the great swamp of the Pantanal is drying out.

For creatures that live in water

this is the hardest time of year.

Their whole world evaporates in the heat.

Capybaras giant cousins of the guinea pig.

These aquatic rodents are as big as a sheep.

Just weeks ago

this was swamp hog heaven

a green lagoon, full of food.

Now it's a dusty desert.

The only grazing could be miles away.

Some of this family won't make it.

It's not just wild animals that are suffering.

They share the Pantanal's grazing with vast herds of cattle.

They're constantly on the move searching for food and water.

Some die on the journey

but the ranchers' loss is the scavengers' gain.

Black vultures gather on a cow that's been dead for two days

but they don't have it to themselves.

A jaguar.

Seeing one in the wild, like this

is incredibly rare especially during the day.

Jaguars are normally hunters not scavengers.

Their prey here are creatures like capybaras.

But for this female even carrion is worth guarding.

The vultures could strip the carcass bare in a couple of hours

given the chance.

But why spend so much energy defending a hunk of rotten meat?

The answer is simple she has two cubs to feed.

Seeing cubs in the wild is even more remarkable.

These cubs are now about a year old

and will stay with their mother for just a few more months.

Until they're independent

she has to find food for three.

Jaguars do sometimes kill cattle in the Pantanal.

It gives them extra food at this critical time

but it also brings them into conflict with ranchers

and that can be fatal.

Jaguars are now threatened throughout their range.

Only a few thousand of these magnificent hunters are left

and the Pantanal is one of their last strongholds.

It's now been six months without rain.

The capybaras have to drink every day

but every day water becomes harder and harder to find.

The last of their grazing shrivels in the heat.

The last pools are little more than liquid mud.

It may not be good to drink but this is the only way to cool off

Fish trapped in these shrinking pools are fighting for life.

This caiman has grown fat

on the seasonal concentration of food.

But if the weather doesn't break soon

it may get stuck in the mud and baked to death.

It's a waiting game.

Nothing but rain can bring an end to this

but the first signs of a change in the weather

only make things worse much worse

especially in the Grassland.

Back in the Cerrado

lightning ignites the tinder-dry grass.

These fires are an annual event.

In the driest years

much of Brazil's great plains go up in smoke.

For scavengers and hunters

the fires are an opportunity

but for anything that can't run or fly

these flames can be fatal.

The fires move fast faster than a man can run.

As they gather strength

they suck in air

from their surroundings and generate their own wind.

The result is a fire that can burn for days.

This looks like the end of the world

but fire has always been an element of this ancient landscape.

Over millions of years

everything that lives here has become adapted to cope with it.

Fire can even be beneficial.

It clears away accumulations of dead grass

and returns nutrients to the soil.

Some animals are killed

but mostly the old, the sick or the very young.

Only five centimetres below the surface

soil temperatures barely rise at all.

Insulated from the outside world in their castles of clay

the termites are unscathed.

Not even fire can stop them.

The heat may have baked their battlements

but they're quick to repair any cracks.

On the termite production line work goes on as normal.

For a few days after the fire

the plains look black and lifeless.

But appearances are deceptive.

Triggered by the heat of the flames

plants release their seeds.

They fall on a fertile bed of ash

cleared of the clutter of last season's growth.

Within days the grass comes alive again.

The fast-moving flames have left the roots unharmed.

Fire actually stimulates new growth

but almost as quickly as it sprouts

it's cut down again by leafcutter ants.

These ants are second only to termites as recyclers.

There can be a million or more in a single nest

and up to thirty nests in a hundred metre square.

They forage up to two hundred metres from the nest

following scent trails to find their way home.

A single ant is tiny

but it can carry twenty times its own body weight.

Together the tonnage they shift is extraordinary.

They can take ten percent of all the new grass.

Unlike termites ants can't digest grass.

Back in their underground nest

they shred it into tiny pieces and grow fungus on it

and the ants then eat the fungus.

And this eats ants.

But in the Cerrado the ants' nests are often deep underground

so the giant anteater finds it simpler to tackle termites.

It uses its long front claws to rip

through the termite mound's hard outer shell.

Even so this isn't an easy meal.

The instant their defences are breached

soldier termites rush to repel the invader

with bites and irritant sprays.

They can really get up your nose

so for the anteater this has to be fast food.

It seldom spends longer than a minute at any one nest

but there's no shortage of mounds to choose from.

Anteaters have roamed these plains for millions of years

time for them to become one of the most specialised of all insect eaters.

With their half-metre-Iong sticky tongue

powerful forelimbs and sharp claws

they're supremely adapted to this way of life.

As it wanders from mound to mound

the anteater leaves a trail of destruction in its wake.

But the termites aren't defeated.

As soon as it's gone

the workers rush to repair the breach with soil, saliva and dung.

Any hole could admit predatory ants

and it destroys the colony's vital air conditioning

so they have to move fast.

In just a few hours the mixture sets hard as concrete.

As you look across the treeless plains

of the Cerrado the termite turrets dominate the landscape.

And they are home for more than just termites.

Their cool interiors provide the only shade and shelter.

But how do you get in?

This bird has the answer.

It's a flicker a kind of woodpecker.

In forest, its relatives nest in holes in trees

so it's well able to hammer its way into a termite mound.

In a living colony the termites might repair the breach

but deserted mounds are soon riddled with holes

and where the flickers go other animals can follow.

They're perfect spots for wasps to build their papery nests

protected from the elements.

As home or lookout post all sorts of animals use termite mounds.

Even the maned wolf has a use for them.

On these featureless plains

they make convenient posts for scent marking its territory

like lamp posts for a dog on a city street.

The October skies begin to fill with clouds until

with a cataclysmic storm the long dry season comes to an end.

The six month drought gives way to six months of rain.

The Cerrado's climate swings from one extreme to the other.

The animals of the plain have survived drought and fire

but how will they cope with this?

Termite mounds give shelter to many animals

but anything small caught in the open could easily drown

like these leafcutter ants.

The rains are the second face of the Cerrado.

For everything that lives here

they bring new challenges and new opportunities

though for the next six months

they'll have to put up with this daily drenching.

At dawn a cold mist clothes a land

that only days before would have been shimmering in the heat.

Fast-rising rivers fill with floodwater from the grassland.

Their banks are lined with the few large trees that grow here

home for blue and yellow macaws.

Swollen by the rains

the rivers rush to the edge of the plateau

and plunge towards the Pantanal below.

The first flush of fresh water signals the start of a new season.

Caiman gather in the shallows

for what will be a high point of their year.

Huge shoals of fish are on the move to their spawning grounds.

Some migrate hundreds of miles.

The caiman congregate in the best places to intercept them.

Male caiman are territorial

but they put their rivalries aside to take advantage of this glut of food.

Lying in the water with your mouth open may look a bit optimistic

but it does work.

There are so many fish that sooner

or later they'll swim into these waiting jaws.

This lazy way of fishing only works when the water is still shallow.

Once the rivers burst their banks

the fish spread out and become much harder to find

so the caiman make the most of this opportunity while it lasts.

Further downstream

the rivers lose themselves in the vast expanse of the Pantanal.

This is home to one of the world's rarest parrots

the hyacinth macaw.

There are less than five thousand in the wild

and most of them live here in the Pantanal.

It's also the largest of all the macaws.

They feed entirely on palm nuts a hard nut to crack.

But not for the hyacinth macaw.

They have the most powerful beak of any bird in the world.

The lagoons of the Pantanal are beginning to fill.

The swamp is so huge and so flat that it takes four months

for the floodwaters to reach the far side.

As the rising water creeps across the plain

the cattle are forced to move again.

The Pantanal is left to its natural inhabitants

like the capybara.

Now they're in their element.

With the onset of the flood

the Pantanal becomes one of the greatest wildlife spectacles on earth.

There are nearly seven hundred different kinds of bird here.

The newly filled swamps are alive with fish and frogs

molluscs and insects almost anything a bird might want.

There's a mass of fresh green growth for the capybaras.

Their grazing helps to keep the water open

and that means even easier fishing for the birds.

As the floods advance

birds time their nesting to take advantage

of the flush of food to feed their young.

Woodstorks crowd their nests into the few trees

that rise above the water.

There can be many thousands in these colonies.

Storks are fish eaters

though they'll take frogs and even snakes.

Here in the Pantanal

they have four hundred kinds of fish to choose from.

The capybaras are breeding too.

The large herds of the dry season have split into family parties

each with a single male and several females and young.

The mothers operate a kind of creche.

One's left holding the babies while the others graze.

She even allows the other female's young to suckle.

But it's a hard life being a baby capybara.

Only one in twenty live beyond their first year.

An anaconda could swallow a full grown capybara whole

let alone a baby.

But it seems no one has told these youngsters.

An anaconda can grow to ten metres.

It's the heaviest snake in the world.

On land, this legendary giant may look slow and clumsy.

Underwater

it's fast and graceful and a killer.

During the wet season

the Pantanal blooms with more aquatic plants

than anywhere else on earth ideal cover for the anaconda.

This young capybara swims almost gracefully underwater

but it's no match for an anaconda.

The snake's flickering tongue smells out its prey

however murky the water.

The hunt is on.

Rather late in the day his mother senses danger.

It's been a lucky escape for this wanderer.

He's shaken, but not stirred.

For the capybaras the living's easy now.

Just weeks ago

this was a desert of cracked dry mud.

Now it's a floating meadow full of food.

At the height of the flood

sixty thousand square miles disappear underwater.

The Pantanal becomes the greatest wetland on earth.

But the change of season has an effect far beyond the Pantanal.

Right across the great plains

the rains bring a flowering of new life.

Back on the high plateau the Cerrado is in bloom.

For now, the hard times are over.

The explosion of growth triggered

by the rains brings a flush of food for the rheas

and these rare pampas deer.

The anteaters have been breeding, too.

As they wander between termite mounds

they travel as much as six miles a day.

It will be months before the infant can walk that far

so it hitches a piggy-back ride from its mother.

The grass has grown tall

almost tall enough to hide the maned wolf

only those ears give it away.

The wolf's no threat to full grown rheas or pampas deer

but it could take their young

though a rhea's kick packs a lethal punch.

Rheas and deer often feed together.

The deer has acute hearing and a good sense of smell.

The rhea has superb eyesight and a high viewpoint.

Working together

bird and deer make an effective early warning system.

A wolf or a jaguar would be hard put to take them

by surprise during the day.

But under cover of darkness

it could be a different story.

It's at night

that the wolf's true nature is revealed.

Night vision cameras give us the first real insight

into the nocturnal behaviour of this shy and solitary hunter.

Using its own natural night vision it set its sights.

Would a skunk make a good meal?

In fact, this smelly animal

is the last thing a wolf would want to tackle.

But it's found something the wolf is after.

Fruit.

For the six months of the dry season the wolf eats mice

but during the rains

this hunter lives almost entirely on fruit.

Its favourite is a relative of the tomato

the 'fruta do lobo' fruit of the wolf.

It grows on a low spiny bush the lobeira.

But there's another surprise.

A second maned wolf arrives on the scene.

The wolves usually live alone spending their days

and nights criss-crossing the plains in a never-ending search for food.

Everything they eat is so small and widely dispersed

that each animal needs a territory of up to ten square miles to support it.

The boundary is scent marked with urine and faeces

no entry signs for other wolves.

So this encounter is a very rare sight.

This playful greeting suggests these animals

already know one another.

Are they a mother and one of last year's young

or are they a mated pair?

Male and female share a territory

but because their food is so scattered they rarely meet.

Perhaps the lobeira fruit has brought them together.

Even at this time of plenty

each wolf still needs a large area to feed itself.

As people encroach on the last natural remnants of the Cerrado

it's ever harder for the wolves to make a living.

Over the entire continent fewer than four thousand remain.

The rains are a trigger for one final extravagant act of nature.

What is about to happen is the most spectacular

event of the Cerrado's year

but the conditions have to be just right.

On just a few days each year in the still

humid air after a heavy downpour

all the termite colonies produce swarms of winged adults.

These males and females

are the founders of a new generation.

The swarms mingle in an aerial dance of courtship.

To find an unrelated mate and start a new colony

they have to leave the safety of the mound

and its protective army.

That gives a window of opportunity for hunters.

Predatory ants attack the emerging termites

before they even have a chance to fly.

Some of these ants actually

live in the outer walls of the termite mounds.

For most of the year they share an uneasy peace with the termites

but when faced with this tempting bonanza

the ants become the neighbours from hell.

The ants work overtime to stock their larders

but they can make little impact on such hordes.

By emerging all at the same time

the termites overwhelm their predators by sheer numbers.

At the end of the day

they're still pouring from their mounds by the million.

Night brings a final incredible twist to the termites' tale.

Like galaxies in a starry sky every mound comes alive

with a thousand twinkling points of light.

And the lights are lethal.

These nocturnal snatchers are luminous beetle grubs

living in the termite mounds.

Termites and flying ants are attracted by the light.

The grubs are sensitive to touch and vibration.

If anything lands within range they grab it.

For the beetle grubs as for so many others

the annual swarming of the termites

is a golden opportunity to lay in supplies.

Of all the creatures that share the termites' castles of clay

these must be the most remarkable.

South America's great plains are an ancient landscape.

They were here long before the forests of the Amazon.

Over millions of years

their inhabitants have evolved the most complex

and intimate of relationships.

But only the most resilient of animals can live here

those that can meet the challenge of elemental extremes.

Drought, Flood and Fire.