This is our planet's hothouse. The jungle. The tropical rainforest

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This is our planet's hothouse. The jungle. The tropical rainforest Powered By Docstoc
					This is our planet's hothouse. The jungle.

The tropical rainforest.

Forests like these occupy only three percent of the land

yet they're home to over half of the world's species.

But how do so many different kinds of plants and animals

find the space here to live alongside one another?

On the dark, humid forest floor the jungle appears to be lifeless.

Often the only signs of life are what you hear.

A male blue bird of paradise is advertising for a mate.

It's quite a performance

but he's not the only bird of paradise here keen to make an impression.

There are nearly forty different kinds on the island of New Guinea

each with a display seemingly more bizarre than the rest.

A riflebird of paradise.

Like many jungle animals, birds of paradise avoid competing with each other

and these do so by living in different parts of this jungle covered island.

The six plumed bird of paradise displays in his special clearing, on the forest floor.

The magnificent bird of paradise favors the low branches of bushes.

His female is modestly dressed.

The male has a good set of lungs

but he'll have to do more than flutter his eyelids, if he wants to impress her.

It'll all depend on his performance.


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The females may be dull looking but they're very picky

and it's time for a really close inspection.

His right side looks fine... but what about his left?

Pretty impressive, but is he magnificent enough?

Oh dear. Her departure says it all.

Generations of choosy females have driven the evolution

of these remarkable displays.

The more extravagant a male is, the more likely he'll be noticed.

New Guinea lies in a warm tropical belt that girdles our planet around the equator.

With abundant rainfall and twelve hours of daylight

three hundred and sixty five days a year, it's here that rainforests flourish.

Surprisingly only two percent of the sunlight filters down to the forest floor.

Down here seedlings struggle to grow

but the gloom is not eternal.

The death of a forest giant is always saddening

but it has to happen if the forest is to remain healthy.

The sudden blaze of sunlight will bring life to the forest floor.

A single hectare of rainforest may contain as many as 250 species of tree.

That's nearly ten times the number that grow in Britain

and the thirst for light triggers a race for a place in the sun.

There's no time to waste.



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A seed that may have fallen only a few days ago, now bursts through the leaf litter.

With so many competitors, getting a good start is critical

but each plant has it's own particular strategy

for making the most of this rare opportunity.

The seeds of hardwoods are quick to germinate

but, like the fabled tortoise, their strategy is to be slow and steady.

Vines and other climbers put all their energy into rapid vertical growth, rather than
girth

though they'll need to be well supported.

The climbers' strategy looks chaotic but there's method in their madness.

Their growing tips circle like lassoes, searching out anchors for their spindly stems.

They put coils in their tendrils

so that if their support moves, they will stretch and not snap.

But the frontrunners at this stage, the first to fill the clearing,

are pioneers like the macarangas.

Their immense leaves capture huge amounts of sunlight, so fueling their growth.

As a result the macarangas grow a remarkable eight meters a year

surging ahead of almost all their rivals.

In the race for the top spot hundreds will start

yet few will ever reach the finishing line, their growth cut short by the diminishing
light.

In less than four years, the gap will have gone

but that's not the end of the race.


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The ultimate winners are the tortoises, the slow and steady hardwoods.

When the short lived pioneers have fallen

it's the hardwoods that take their place, and a fifty meter giant, like this one,

may keep it's place in the sun for another two hundred years.

At the top, is the canopy, the engine room of the jungle.

It's up here that most of the animal life in the rainforest can be found

But despite the apparent abundance of vegetable food, gathering it is seldom easy.

With no real seasons

each tree flowers or fruits at a different time of the year

which means that food is very widely spaced.

Monkeys, like these tamarinds, must search the canopy for all kinds of food

if they're to survive.

but across the world's rainforests there's one type of fruiting tree

that always delivers: the fig.

Wherever they grow, figs are a magnet for the great diversity of animals.

In the Amazon, the first to appear are the spider monkeys.

These large primates are big fig eaters

But they won't have the tree to themselves for long. Others will want a share.

like the diminutive emperor tamarinds.

The tamarinds love figs too, but being petite means they're easily scared off.

Squirrel monkeys are also small but they have strength in numbers.



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Their timeshare on the tree may be short, so their tactics are more smash and grab.

Capuchin monkeys are the bully boys in these forests

and they want the ripe figs for themselves.

Figs are one of the few trees that fruit the year round

so when other food is scarce, these fruits are always available somewhere or other.

Even for leaf eaters, like howler monkeys the ripe figs are just too good to miss.

And howlers are too big for the capuchins to chase off.

Figs are so popular, that as many as 44 different kinds of bird and monkey

have been seen working a shift system on a single tree.

Because fruiting trees are so valuable, many monkeys are territorial

And if you live in the treetops

there's perhaps no better way of staking your claim to a territory, than this.

The calls of the siamang gibbons begin as a duet

between the dominant male and female.

The rest of their families soon join in, and it results in a frenzy of activity.

The calls can carry over a mile, and their message is clear.

They tell any neighboring siamangs this is our territory. Keep out.

Up here the calls of siamang gibbons seem to dominate the airwaves

but with the jungle's incredible diversity

there are countless others trying to be heard too.

Every layer seems to beat to a different tune.

In the early morning the forest's chorus is particularly rich.


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Sounds travel further in the cooler air

But few calls can penetrate as far through the dense vegetation as this one

the deep bass solo of a male orangutan.

In the middle of the day little stirs in the jungle

and the hot dense air muffles the sound.

As the afternoon wears on, a different set of players begin to warm up.

Insects work in harmony, timing their calls to fall between the notes of others.

Many singers stick to precise schedules

and right on cue the six o'clock cicadae.

Night brings out a whole new orchestra.

The cacophony of competing calls seems deafening to us

but frogs ears are tuned to hear only the calls of their own kind.

The songs of courtship echo from all around.

Male gliding leaf frogs leap from the treetops.

To slow their descent, they use their huge webbed feet as parachutes.

These large tree frogs spend most of their lives in the high canopy

and only come down when it's time to breed.

Once settled, they begin to serenade their unseen females.

Now it's time for the females to make their move.

There's no shortage of suitors, but this female has already made her choice.

She's heading towards the loudest call, because loud calls come from big frogs



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and big is best, but to reach him she must run the gauntlet of a gang of smaller suitors.

Their only chance of mating is to make a sneaky interception.

He's scored.

But with more females arriving all the time, it's not over until the fat frog stops singing.

Feet, so vital for gliding, are now put to other uses.

Two's company, three's inconvenient

but in any case, all male frogs are equipped with dry thumbs

which enable them to get a vice like grip on their moist partners.

It's a case of first come first served.

Living in such a humid environment, means jungle frogs are less tied to puddles and pools

and these even lay their eggs out of water.

There's little chance of them drying out

and up here they're safer from predators.

Surprisingly, it doesn't rain every day in the rainforest

but more still falls here than anywhere else on Earth.

On average, over two meters a year.

A single tree can suck up hundreds of tons of water each year

But the trees can't use all this water

so, much of it returns to the air as vapor, forming mist and clouds.

In the Amazon, the largest unbroken stretch of rainforest in the world,

half of all the rainwater that falls, comes from clouds produced by the trees themselves.

With so much rain, it's not surprising that many of the worlds largest rivers


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are found in rainforests.

Inside the forest, the high humidity

creates the perfect conditions for a strange world, where life is built on decay.

Amoeba like slime molds cruise the surface, feeding on bacteria and rotting vegetation.

Fungi also flourish on decay.

These are the fruiting bodies of the fungi, the only visible sign

of a vast underground network of fungal filaments.

In temperate forests, the buildup of leaf litter creates rich stores of nutrients.

That however, doesn't happen here.

Nutrients that reach the soil are leeched out by the rain

but fungi are connected to tree roots by their underground filaments

and by quickly consuming the dead

they help to recycle crucial minerals straight back into the trees.

And this recycling happens faster here, than anywhere else on the planet.

There are thought to be nearly a million different types of fungi in the tropics.

The vast majority still unknown to science

But one thing's for certain

without fungi, rainforests could not exist.

Nothing goes to waste in the rainforest.

The fungi become food for others like these beetle larvae.

Finding the fungus isn't a problem for the grubs



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since their caring parents actually show them the way.

Incredibly, 80% of all insects live in jungles

fewer more successful than the ants. There can be 8 million individuals in a single
hectare.

but jungle ants don't have it all their own way.

These bullet ants are showing some worrying symptoms.

Spores from a parasitic fungus called cordyceps

have infiltrated their bodies and their minds.

It's infected brain directs this ant upwards

then, utterly disorientated, it grips a stem with it's mandibles.

Those afflicted, that are discovered by the workers

are quickly taken away and dumped far away from the colony.

It seems extreme, but this is the reason why.

Like something out of science fiction

the fruiting body of the cordyceps erupts from the ant's head.

It can take three weeks to grow

and when finished, the deadly spores will burst from it's tip

then, any ant in the vicinity will be in serious risk of death.

The fungus is so virulent, it can wipe out whole colonies of ants

and it's not just ants that fall victim to this killer.

There are literally thousands of different types of cordyceps fungi

and remarkably, each specializes on just one species



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but these attacks do have a positive effect on the jungle's diversity.

Since parasites like these stop any one group of animal getting the upper hand.

The more numerous a species becomes, the more likely it'll be attacked by it's nemesis

a cordyceps fungus.

With so much competition, jungles have become the home of the specialist.

Now this animal, in the island of Borneo, is one of the most unusual.

It's a colugo, or flying lemur, though this is something of a misnomer

as it doesn't actually fly and it certainly isn't a lemur

in fact nobody's quite sure who it's closest relative is.

The colugo depends on a diet of young leaves

and to find enough of them, it must move from tree to tree.

The leaves are not very nutritious, but then, getting around doesn't use much energy.

In a single night, a colugo might have to travel as far as two miles

but that task is made easier by it's superior gliding skills.

The secret of success in the competitive jungle is specializing

and this has led to the evolution of some very intimate relationships

between plants and animals.

These are pitcher plants also from Borneo.

Adapted to living in very low nutrient soils

the pitcher plant gets most of it's nourishment from insects lured to nectar glands

on the underside of the lids.

Once onboard, the waxy sides of the pitcher ensure there's little chance of escape.


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Most slip to a watery grave.

At the bottom of the pitcher glands secrete enzymes

which help to digest the corpses, so feeding the plant.

But not all visitors have a fatal attraction to the pitchers.

The red crab spider spends it's entire life in the pitchers, hanging on with threads of
silk.

Instead of building a web, it relies on the water filled pitcher to trap it's food.

When an ant falls in, the spider simply waits for it to drown

and then abseils down for a spot of fishing.

Alive, this ant would be far too dangerous for the spider to tackle

so, using the pitchers as traps, means it can get bigger meals

and the spider doesn't rob the pitcher of everything.

The digested remains of it's booty will end up in the water

providing instant food for the plant.

Other food, like mosquito larvae, seems to be out of reach

but the spider has another sup rising trick.

By taking it's own air supply trapped in a bubble

the crab spider can actually dive to the very bottom of the pitcher.

Once the prey is captured, the spider hauls itself back up it's silken safety line.

The pitcher is a one stop shop for this spider, but it's not alone.

In the jungle there's competition for everything, even a small water filled pitcher plant.

Such specialists create the jungle's remarkable diversity


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but finding enough food to survive is so challenging

that most animals living here tend to be small

though there are exceptions.

This is the Congo in Africa.

It's a vast wilderness and the least explored of all jungles.

From up here the forest looks similar to the ones that grow in the Amazon or Southeast
Asia.

but down below there are some unexpected sights.

Crisscrossing this forest, are countless miles of highways

and they were made by something big.

Forest elephants roam great distances in their search for food

but to survive, they must emerge from the gloom of the forest.

And clearings like this one, are a magnet for elephants from far and wide.

These elephants live in much smaller groups than their savanna cousins.

This might be the first time that one group will have seen another for a month.

For the adult males it's a welcome break in an otherwise largely solitary existence

and they're not the only animals attracted to the clearing.

Forest buffaloes and red river hogs are also regular visitors

as are bongos, which are very difficult to see outside these clearings.

All these large forest animals have come here to collect an essential element of their
diet

that lies buried beneath the mud.



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And the elephant's trunk is the perfect tool for reaching it.

To get what they seek

the prospecting elephants must first blow away the covering layer of silt.

Satisfaction at last.

They're collecting a particular kind of clay

that contains vital minerals scarce in their natural diet.

It may be mud, but there's just nothing quite like it for enriching the blood.

The clay also helps to absorb the toxins found in many leaves that the elephants eat.

There are other benefits to coming here.

These clearings are the only places where the forest elephants

can get together in such numbers.

When they return to the forest, they will have to go their separate ways, once more.

If large animals are rare in jungles

then groups of large animals actually living together, are even rarer.

This posse of hunters is not only formidable, it's also very large.

In their search for food chimpanzees move effortlessly

between the forest floor and the canopy.

They're one of the few jungle animals able to do so.

Figs are a vital part of a chimpanzee's diet

and some just can't seem to get enough of them.

But there's something special about this stretch of forest in Uganda.

Fruit is actually abundant


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and a lot of food supports lots of chimps.

At a hundred and fifty strong, this community of chimps

is the biggest yet found in Africa.

Their numbers are so large, that they need a big territory, lots of fig trees

and they're willing to fight for it.

These calls announce the start of a raid into land controlled by their neighbors.

As they leave their core zone, the patrol goes silent, occasionally stopping to listen.

Signs of the enemy are detected and examined closely.

The chimp militia are now at the very edge of their territory.

All need to be on maximum alert.

Then it's wait and listen.

An unfamiliar chimp call raises the tension.

It's an uncertain time. The size of the rival group is as yet unknown.

Not far away the neighbors are feeding in a fig tree

oblivious to the approaching dangers.

The patrol moves off with a sense of purpose.

They must remain silent until they close in on their rivals.

The attack is on.

To intimidate their opponents, the aggressors scream and drum on buttress roots.

Several males corner an enemy female.

It's a ferocious attack, and she's lucky to escape with her life.



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Others are not so fortunate.

The battle won, a grizzly scene unfolds.

An enemy youngster has been caught and killed.

The carcass is shared between members of the group, and eaten.

Killing a competitor makes sense if you want to protect your food supply

but exactly why they cannibalize the dead chimp, is not fully understood.

It may simply be a chance for some extra protein.

Teamwork has brought this group of chimps great success

but they'll soon reach the limits of their power.

The competition for resources ensures that no one species dominates the jungle.

The rainforest's great diversity has come at a cost.

It has made them the most finely balanced ecosystems in the world

only too easily upset and destroyed by that other great ape

the chimpanzee's closest relative

Ourselves.




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