01x03 - Jungles
And, here, it does so in abundance.
The jungle is Eden.
It covers less than 6% of the Earth's surface but it's home to half of all the plants and animals on land.
Jungles have just the right amount of light, water and nutrients, and they have had every day for millennia.
Life here should be easy.
This is an indri.
It's a primate, like us.
And these forests in Madagascar are its home.
But to survive here... it has to face one major challenge.
Paradise is crowded.
Life fills every niche.
And, at any one time, a staggering variety of species and countless individuals are striving for space and food.
Like every jungle animal, indri have to find their own way to survive in the most competitive place on Earth.
Jungles are complex places... tangled three-dimensional worlds created by lush tropical vegetation.
90% of the animals here spend their whole lives up in the trees.
And each of them has to find its own way of getting around.
Hanging 100 feet above the ground, a spider monkey.
They travel in family groups and find everything they need in the top storey of the jungle.
Up here isn't a place for the faint-hearted.
With long limbs and a prehensile tail that can grip like a hand, they're built for climbing.
But imagine having to learn these skills as high up as this.
One third of spider monkeys never make it to adulthood.
This youngster is only a few months old.
Her future depends on her ability to climb.
Playing on a practice tree with her older brother and sister, she's already learning to use her tail as a safety line... under her father's close watch.
She's keen to join in the game but she's the youngest and, as is the way of things, she's not always welcome.
So she chooses her own place to play.
But not all trees are the same.
This one is for more advanced climbers.
Room for improvement.
Meanwhile, some of her family have moved on to look for a new patch of fresh food.
The top of the canopy isn't for youngsters.
But Father's not looking and the temptation to join the others is irresistible.
She'll need to be careful.
A fall from here would mean certain death.
It's the first time she's been as high as this on her own.
As she climbs still higher, the branches get thinner and thinner.
Her tail has caught her... but now she's stuck in mid-air, unable to reach any other branch.
Father, however, was watching.
He's big and strong enough to form a bridge with his body so that she can climb to safety.
But it's not just monkeys that live here, up in the treetops.
And, if you are small, finding the right tree can mean a home for life.
He's a Draco lizard.
He's only the size of a pencil and he eats ants.
This one tree could provide him with all he will ever need... a conveyor belt of food.
It's a perfect place to settle down.
Well, it would be... but there's already someone here.
This larger male is the tree's owner.
And Dracos don't share.
The owner's flag is a warning.
Trespassers won't be tolerated.
The owner's not only intimidating... he's prepared to battle.
A d*ad end.
Safety is a long way away.
Now he must choose.
Fight... or flee?
Only in the jungle do you find lizards that can soar like dragons.
He can travel over 100 feet in a single leap.
It's a very fast and efficient way to move through the jungle.
Maybe this new tree will have food and no resident owner.
Everything in the jungle has to compete for space.
Only 2% of the sun's rays reach the ground... so even the plants must battle for the light they need if they're to grow.
300 years ago, this Hura tree began its race for light.
And every day since, it has absorbed the water and sunshine it needed to grow into a giant.
It has succeeded in doing what every tree must do to survive... rise above the gloom of the jungle floor.
And, what is more, its success has given life to others.
Its branches now carry 1,000 other plants.
These particular ferns, figs and orchids live only on the branches of other trees.
1,000 plants growing on one single tree.
Throughout the forest, this story is repeated endless times.
As a consequence, jungles are home to more species of plants than anywhere else on Earth.
And they, in turn, support a wealth of animals.
In Ecuador, the competition is at its most intense.
Here, there are 100 species of hummingbirds alone... all fighting for nectar.
Each flower only has a small amount at any one time, and so it's first come, first served.
One hummingbird has gone to great lengths to avoid conflict with other species.
Swordbills are the only bird with a beak longer than their body.
And some flowers are too elongated for the other 99 species of hummingbirds here to feed from them.
A swordbill's extraordinary beak, however, enables it to reach the places that others can't... the top of this flower, where the sweet nectar is produced.
It has found a solution that means it doesn't have to join the fight.
And, as each long flower blooms, it gives the swordbill a fresh supply of food all to itself.
But having a beak longer than your body does have its drawbacks.
For a start, it's tricky to keep it clean.
Harder still, how do you preen your body feathers?
Unlike the other hummers, swordbills can't reach their feathers with their beak.
The only option, a good old scratch.
It's a little unrefined... but a small price to pay for an exclusive food supply... especially when feeding times are only too frequently interrupted by storms.
Jungles are the richest places on Earth because of one remarkable fact... they make their own weather.
Every day, water rises from the surface of the leaves as vapour.
It's as if the trees breathe out clouds.
They gather over the forest until, finally... they burst.
Rain is the lifeblood of every jungle.
And all have to do their best to endure the daily downpour.
In some jungles, like here in Brazil, it rains so much that, for part of the year, the trees are almost totally submerged.
The forest floor is 30 feet below the water's surface.
This is a mysterious world, a place few people have ever explored.
We have much to discover about the animals for which this is home... including some you might never expect to find amongst trees.
Here, 1,000 miles from the sea, are dolphins.
A newly identified species of river dolphin found nowhere else on Earth.
In these black, tangled waters, they have become almost totally blind, so they move slowly, carefully using their sonar to scan the forest floor for fish.
If this forest can hide a new species of dolphin... what else might there be here, awaiting discovery?
At the shallow margins of the flooded jungle, rivers flow through lush vegetation.
Here, food is so abundant, it supports giants.
Capybara, the biggest rodents in the world...
...giant otters the size of a man...
...and the rulers of these rivers...
They grow to ten feet long and k*ll anything they get between their jaws.
But there are more artful hunters... drawn here from the surrounding forest.
A jaguar, the supreme jungle predator.
The river marks the edge of his territory... but here he has competition.
He's now in the territory of a female.
She has ruled this stretch of river for five years.
This is her place to hunt.
Capybara are strong and wary.
The key is stealth.
She needs to get within three feet if she's to pounce.
Not this time.
She's not the only female here.
Each part of this jungle's edge is ruled by a different queen.
Few places on Earth have enough food to support so many big cats.
The male hunts in a different way.
Weighing almost 300 lbs, it's hard to be stealthy... and with so many other jaguars around, he doesn't bother with wary capybara.
He seeks a different prey.
He's become a k*ller of K*llers.
Jaguars have the most powerful bite of any cat.
And he knows the caiman's most vulnerable point... the back of its skull.
Hunters living in the dense understorey of the jungle come in all shapes and sizes.
But they share a problem.
How to tell what is a plant, and what is prey.
This is a game of hide and seek that can be won or lost in the blink of an eye.
The long contest between predator and prey has produced mimicry of astounding accuracy.
A leaf-tailed gecko masquerading as lichen.
Some animals take camouflage a stage further still... and these streams in Costa Rica are home to one of the most remarkable.
A glass frog.
A male, and tiny, no bigger than your fingernail and almost entirely transparent... as he needs to be.
Almost everything that walks past here could eat him, even a cricket.
His best chance is to stay absolutely still and trust that the cricket looks right through him.
Danger passed, and that's just as well, because he is a father... and he's guarding some very precious eggs.
For the last few weeks, females, one after the other, have visited him and entrusted him with their offspring.
Some are now almost ready to hatch.
There are several clutches on the leaf, and those at the top, the most recently laid, are barely a day old.
But in the jungle, there's always someone out to get you.
This wasp is a specialist hunter of frogs' eggs.
It's noticed the wriggling tadpoles at the bottom of the leaf.
He mustn't move.
The youngest eggs are the most vulnerable, and he can't guard them all.
But these tadpoles are not as helpless as they might appear.
Incredibly, the unhatched tadpoles can sense danger, and the oldest and strongest wriggle free and drop into the stream below.
The eggs at the top of the leaf, however, are still too young to hatch, and now the wasps know they're there.
But the male's back looks very like the youngest cluster of eggs... and that seems to confuse the wasps.
Using his own body as a decoy is a huge risk.
The wasp stings could k*ll him.
He's managed to save most of his young.
He'll have to remain on guard for another two weeks, but in the jungle, just surviving the day can count as a success.
With the coming of the night, a new cast of jungle characters takes to the stage.
Flying insects begin to glow as they search for mates.
Fungi, unlike plants, thrive in the darkness of the forest floor.
They're hidden until they begin to develop the incredible structures with which they reproduce.
Each releases millions of microscopic spores that drift invisibly away.
Many have fruiting bodies that reach upwards to catch any feeble current there might be in the clammy air.
But this one, as it grows, becomes luminous.
Why fungi light up has remained a mystery... until now.
Scientists studying the brightest fungi in the world think they may have an answer.
Like a beacon, the light attracts insects.
From far and wide.
To this click beetle, a bright light means only one thing... a female click beetle, so he flashes in reply.
But he doesn't get the reception he was expecting.
Confused, he starts searching for a female, and that helps the fungus.
By the time he gives up, he's covered in the fungus's spores.
And, as he continues his quest for a female, he carries these spores to other parts of the forest.
And there are even stranger things glowing in the jungle night.
These are the multicoloured lights of a railroad worm.
It's not really a worm, but a poisonous, caterpillar-like beetle.
The yellow lights warn other creatures to keep out of its way.
It's hunting for millipedes.
When it finds the trail of one, it switches off its yellow lights.
Now it only has a red light on its head.
Millipedes can't see red light.
So, to them, the railroad worm in stealth mode is virtually invisible.
And that is the end of the millipede.
Competition in the jungles forces animals to specialise in every aspect of their life, including courtship.
This has produced some of the most beautiful and elaborate displays on the planet.
A male red bird-of-paradise, competing to attract a female by dancing.
One has come to survey what's on offer.
She is an independent lady, and she will select whichever male takes her fancy.
She makes her choice.
But now she doesn't seem quite so sure.
No? Perhaps he's just a little too keen.
Maybe he'll have better luck tomorrow.
Red birds-of-paradise display in the treetops.
Other members of the family dance in the gloom of the forest floor.
This is a Wilson's bird-of-paradise.
He's brightly coloured, but about the size of a sparrow.
He's lived most of his life alone, but now he's an adult, and he too needs to attract a mate.
This little patch of light might help him do so.
First, he tidies things up.
Showing off in this jumble of leaves wouldn't be easy, and his beauty will stand out better against a plain background.
He doesn't want bright leaves to divert a visitor's attention.
They all need to go.
Even the green ones.
Especially the green ones.
His stage is set.
A central pole, and a little patch of light.
And now, he must hope a female hears his call.
He can wait here for weeks on end.
At last, a female.
Time to take up position.
She will judge him by the brightness of his feathers.
But for the female to see him at his best, he needs her to perch directly above his stage, under the light.
This might be his only chance to shine.
Now, when she's looking directly down on him, he reveals a display for her eyes only.
In the gloom of the forest floor, he is a dazzling blaze of iridescent green.
The brightest leaf in the forest.
And that does the trick.
Each animal must find its own way of surviving the competition of the jungle.
This crowded world is so full of invention that almost all kinds of animals on land can trace their origins back here... including us.
These forests in Madagascar are home to one of our distant cousins.
This female indri has fought to keep this particular patch of forest safe for herself and her family.
Every morning, the family come together to sing, their way of reminding others that this is their home.
Indri are so closely adapted to living here that now they can live nowhere else.
For them and the billions of animals with whom they share their home, the jungle is a sanctuary.
But this is changing.
Even in the ten years since the head of this family was born, one million hectares of the rainforest have been destroyed in Madagascar alone, and, with it, half the indri families that once lived there.
The local people say the indris are our brothers and their song is a call to remind us that we, too, once depended on the jungle.
This Eden is still a place of wonder and magic.
Something, surely, worth protecting.
Jungles are still some of the least explored places on Earth, and with good reason.
They are testing places to work.
Here in the flooded forests of Brazil, the team are on the trail of a newly discovered species of river dolphin.
So little is known about it that just finding it will be a challenge.
Their base for five weeks is a hut on the only bit of dry land around, but it's already occupied.
It appears someone's been making a nest.
A resident rat.
Hello, little rat.
And on the food cupboard...
Hello. Are you a bit shy?
If the housemates are hostile, the hitchhikers are even worse.
A large spider.
Oh, my God.
And a colony of aggressive red ants looking for a ride.
Shall we knock into them?
They'll board the boat like a bunch of pirates, and they'll gnaw our faces off.
That might not be quite true, but intimidating animals are the least of their problems.
The flooded forest is not only vast, it's impenetrable, and this new species of dolphin could be anywhere in 150,000 square miles of tangled treetops.
But the crew have a plan.
Dolphins use sound to find their way through the flooded forest by making clicks. Sonar.
Waterproof microphones allow the crew to eavesdrop on the dolphins, and so follow them.
But that's easier said than done.
So, this is the clear path.
Can you see it? There.
It takes them a week to get their first glimpse of this new species, and even then, it lasts less than a second.
There appears to be only one dolphin.
And, frustratingly, it can pop up anywhere without warning.
Been looking through the water and seeing bodies kind of appear out of the murk, and then disappear again.
Eventually, the dolphin leads the crew to an open gap in the forest.
We made it! Yay!
Here, at last, there may be a chance of getting something in the can.
Their first sh*t, but again, a single breath, and then it's gone.
With the dolphin as close as this, the crew can try a different technique... towing an underwater camera behind the boat.
Dolphin literally just came up parallel to it.
The problem is that the water is so murky, that the dolphin is almost invisible, even when right next to the camera.
However, now the dolphin is in this channel, the crew can try a different tack.
Michael Sanderson is a drone operator.
As long as the dolphin's in open water, it might be possible to follow it from the air.
We've worked out the dolphins seem to be here, and we can do the drone work, so this is our kind of best bet.
Leaving Michael and his drone on the sand spit, the crew head back to open water.
But this is called the flooded forest for a reason.
The rain here can be torrential, and although storms normally pass quickly, this one is clearly not a normal storm.
Is it not working?
The motor has broken, and with the boat flooding, the crew must head for the bank.
It looked like the rainstorm was going to pass, and it hasn't passed at all. It's very, very heavy, and I'm soaked through to the skin.
They're stranded, the kit is getting drenched, trees are falling, and Michael is trapped somewhere down-river.
This is the hardest rain I've ever seen in my life.
I'm hoping Michael's all right.
And there's been tree fall all up around behind us.
Michael's down there on a tiny little sand spit, with the other boat, with his opticopter out.
Kind of scary.
After two hours, a break in the storm gives Michael a chance to rejoin the team.
Just got caught in one of the heaviest storms I've ever seen.
Got up to this much water on the tarp, and the other one, so I don't know if this is going to live any more, because that was on the floor.
It looks like it's game over for the drone.
Yeah, it was pretty scary, wasn't it?
Over the next 12 hours, the storm returns again and again.
If this bad weather continues, the crew may not be able to get back out to the dolphin.
The next morning, clear skies, and the drone might be fixable.
But the longer it takes, the more chance that the dolphin will have returned to the flooded forest, and then it'll be back to square one.
But finally, their luck is in.
The dolphin is still there.
For the first time, they have a chance to film from the water and the air, and finally discover what this elusive animal is really doing.
They were in the boat and they were looking around and going, "Yeah, there are some bubbles."
We were flying with the drone and we could see dolphins, and while they thought they could only see one dolphin, we saw five.
And they had no idea.
The crew are surprised to find these dolphins aren't solitary, but come together to hunt as a team.
You're starting to see stuff with the drone that you suddenly go, "I thought there was one dolphin there," and then you count that there are five and then you're looking in one place and they're all behind you, laughing at you.
This new perspective has given the crew a first glimpse into a mysterious jungle animal in one of the least-known corners of the Earth.
Next time... a land of extremes that pushes life to the limit.
Animals have extraordinary ways of dealing with the hostile conditions.
Creating the most epic survival stories on Earth.
These are deserts.