Jungle The Living Planet

BIRDS SQUAWK

I am sitting surrounded by the greatest proliferation of life

that you can find anywhere on the surface of the earth.

I'm up in the canopy of the jungle, the tropical rainforest.

Here there is a greater bulk of life, both animal and plant,

and a greater diversity too, than can be found anywhere else at all.

This huge proliferation comes from two main causes -

warmth and wetness.

The wetness comes from the abundant equatorial rains,

the warmth from the tropical sun.

Between them, those two factors have created the jungle,

which stretches in a broken green band right round the earth.

This particular patch lies in South America, right across the equator,

stretching for 600 miles both north and south of it

in a vast blanket, almost unbroken except for the rivers.

Here there is probably more unexplored territory

than anywhere else in the world.

Travel east from here along the course

of that greatest of rivers, the Amazon,

and you reach the Atlantic.

Continue along the line of the equator, across the ocean,

and you come to the west coast of Africa,

another gigantic river, the Zaire, that used to be called the Congo,

and another vast tract of jungle.

The eastern side of Africa doesn't get as much rain

and the jungle dwindles into savannah,

but across the Indian Ocean the great green rainforest reappears

along the western edge of India and Sri Lanka.

It covers south-east Asia, Burma, Thailand and Malaysia,

the huge islands of Borneo and Sulawesi and the smaller archipelagos

of Indonesia, and farther east still, New Guinea.

Beyond lies the vastness of the Pacific,

for the most part, empty of land,

except for scatterings of tiny islands,

until, having girdled the earth around the equator,

you come back to the greatest expanse of all - the Amazon jungle.

The kind of tree I've climbed doesn't grow in groups

but as single, isolated individuals,

and it's by far the tallest tree in this particular jungle.

It's a kapok, and it grows to over 200 feet high,

so that if the canopy of leaves formed by the rest of the jungle

can be called a sea of leaves, then the crown of the kapok

is an island which rises above that sea,

and it has a climate all of its own.

There is more sunshine up here than below and there's also wind -

something that is virtually unknown down in the depths of the forest.

The wind causes some problems.

It can rob a tree of its moisture by evaporation from the surface

of its leaves, so the kapok has very small leaves.

But the wind also brings a benefit -

it distributes the kapok seeds, which are extremely fluffy...

..and they float gently across the top of the canopy

for mile after mile.

The crowns of these giant trees are the home

of the biggest and most fearsome of all jungle birds.

There are flying hunters very like this one in most jungles.

In South America, the harpy, in Africa, the crowned eagle,

and here in Malaysia, the hawk eagle.

All patrol above the surface of the canopy, occasionally plunging down

into the leaves at great speed to seize a squirrel,

a bird or even a monkey. All produce just one nestling

which they must feed with meat for almost a year

until it too is big enough to hunt.

These high outposts above the jungle are excellent vantage points

from which to scan life in the canopy below.

But few other creatures dare fly above that sea of leaves

when there are eagles about.

Coming down from the airy, sunlit branches of the kapok,

you leave the breeze and the dazzling sunshine and enter a different world.

Here the warm, still air is heavy with moisture,

there's hardly a breath of breeze,

the leaves above cut out much of the sunshine.

The canopy - millions of leaves

stretching in a vast, endless mosaic of green,

each individual leaf exactly angled

to collect the maximum amount of light.

Many have a special joint at the base of their stalk

that enables them to twist and follow the sun as it swings overhead.

It's an isolated world, many of whose inhabitants

are born here and will die here, without ever leaving it.

Insects are everywhere.

There seems no limit to the variety of their shapes and their colours.

Some prey on others, most derive their sustenance from the trees,

collecting the seeds, sipping the nectar,

sucking the sap and munching the leaves.

Weaver ants use the leaves as walls for their nests.

Workers, with their feet hooked on one leaf, lock their jaws on the edge

of another and haul the two together.

While they hold the leaves in position,

other workers use the colony's grubs as tubes of glue,

gently squeezing them so that they produce threads of sticky silk

which they weave back and forth across the junction.

Eventually they produce an enclosed globe,

within which they can rear their young.

The insubstantial green terraces of the canopy

are the pastures of the jungle

and a multitude of creatures graze on them.

These, in South America, are squirrel monkeys,

but every jungle has its monkey troops

that scamper with total confidence

through the branches, fastidiously selecting the right kind of tree,

the juiciest bud...

or the particular shoot that most takes their fancy.

There are no seasonal changes here

comparable to winter and summer further north,

so there is no one time for the shedding and the renewal of leaves.

Neither is there any particular season for flowering.

In this eternal summer, trees vary greatly in their flowering cycles.

Some bloom every ten months, others every 14.

A few may only flower once in a decade.

But the rhythm is far from haphazard,

for all the individuals of one species in the forest

produce their flowers at about the same time,

as they must if they are to cross-pollinate one another.

With so little breeze within the canopy,

the trees can't rely on the wind to do the work of pollination.

Most depend on insects and other animals,

bribing them with lavish feasts of pollen and nectar.

Bigger creatures have to be persuaded to transport the heavier seeds.

Their rewards are the fruits.

Birds do much of this work during the day, swallowing the entire fruit,

digesting the flesh and voiding the seeds later and elsewhere.

At night, other creatures take on the job.

The majority of bats eat insects, but in the tropics many have specialised

in collecting fruit and live on nothing else.

There are a great number of different kinds of figs in the jungle,

each with its own fruiting rhythm.

Since the bats are such accomplished fliers,

they can range far over the jungle

and can always find figs of some kind ripe somewhere.

Some feast on them in the trees, many prefer to carry them away

and feed in the familiar safety of their roosts.

Trees can be cropped in many different ways.

The pygmy marmoset has specialised in collecting sap.

The front teeth in its lower jaw project forward,

and with them, it scrapes away the bark causing the sap to run.

Marmosets live in families, each with its own territory in the branches,

and each has at least one of these sap wells

which the family carefully keeps open and productive

and vigorously defends.

Still though the air is, it carries the microscopic spores of ferns

and mosses which lodge in the crevices of the tree bark and sprout.

As they flourish and decay, their remains accumulate into a compost

on which other plants can grow.

Their dangling roots collect moisture from the humid air,

and so the broad branches become balconies

loaded with orchids and bromeliads.

Bromeliads are relations of the pineapple

and each one has its own population of animal lodgers.

The rosette of leaves forms a chalice that is always full of water,

a useful drinking place for the canopy animals.

For some frogs, it's more than that. It's a nursery.

This little female arrow poison frog laid her eggs on a leaf.

As they hatched, she allowed a tadpole

to wriggle up onto her moist back.

Now she must find a pond for it to swim in.

She reverses into the water and allows the surface tension

to pull her tadpole off.

Several species of arrow poison frogs use bromeliads like this,

and most regard their parental responsibilities

as being over at this stage.

Mosquitoes are likely to lay here, so with luck,

there should be some wriggling larvae for the tadpole to feed on.

But this frog doesn't take that chance. Every three or four days,

she returns to every plant where she left a tadpole

and in each she lays more eggs.

But these are not fertile. They are food for the tadpole

and will sustain it until it's big enough to catch insects for itself.

For such frogs, like so many creatures up here,

the canopy is a complete world,

suspended above the surface of the earth,

that they never need leave.

When you descend from the canopy,

you leave behind the most densely populated part of the jungle

and enter a kind of aerial halfway house of spindly saplings,

hanging lianas and bare branchless trunks.

Here, I am about halfway down, about 70 feet above the floor,

midway between the ceiling of leaves in the canopy

and the carpet of leaves down below.

Up here, there are very few leaves -

these huge tree trunks don't sprout very many.

There's nothing much but empty space,

so very few creatures come here to feed,

and apart from birds and some flying insects,

the only creatures I'm likely to see

are those that use these huge tree trunks and the dangling lianas

as vertical highways between the world above and the world below.

Snakes with no legs and claws with which to hold on

might not seem to be well suited to climbing, but, in fact,

some can ascend the vertical trunks with astonishing ease.

The paradise tree snake of Borneo maintains its grip

by pressing sideways with its coils and propels itself upwards

by sending ripples down the line

of angled backward-pointing scales on its underside.

But it has an even more unexpected accomplishment.

By pulling its ribs forwards,

it flattens its body, turning it from a rod into a ribbon

so that it catches the air,

and by waving its coils it can, to some extent,

control the direction of its glide.

But in these Borneo forests, there are even better gliders.

This squirrel has a cloak of furry skin that stretches

from its wrist to its ankle.

When it's about its normal business, the skin looks a bit untidy,

as though the animal were rather sloppily dressed,

but when the squirrel leaps,

then it becomes the very summit of gliding grace.

Most other mammals in this midway zone

travel from tree to tree along the lianas.

Marmosets are capable jumpers and confidently leap a yard or so.

But they are not always convinced that they can make it.

The uakari is not nearly so athletic.

It sometimes avoids too big a jump by throwing its weight back and forth

on a sapling, so that it sways and carries it across to the next tree.

Few large creatures visit this middle part of the jungle to feed,

for there are comparatively few leaves here,

but lizards scuttle up and down the trunks, for there,

as almost everywhere else, there are insects to be collected.

Spiders hunt here too.

These termites collected their food

from rotting vegetation on the ground.

They are laboriously carrying it all up here because it's up here,

within the trunks, that they have built their nest.

Other termites hang their nests from branches

and these are often commandeered by others.

A bird originally dug this hole, but the bat took it over

and now uses the termites' work as a convenient roost

from which to hawk for insects.

The pillar-like trunks of the huge trees provide homes for a few birds.

A big bird like a macaw needs a nice open approach to its nest,

and a hole here is relatively safe,

for few non-flying robbers can reach it.

This hole started when a dead branch fell, but the macaws

have enlarged it greatly.

They usually have just two chicks,

but keeping them properly fed is a considerable labour,

for they will stay in the nest hole for over three months.

Like all parrots, macaws feed their young

by regurgitating chewed-up fruit from their crop.

Both parents labour away, bringing loads of fruit throughout the day,

for it's bulky food and the youngsters need a great deal of it.

Holes in tree trunks are very valuable properties.

Only a few creatures can make them,

but plenty will gladly move into them.

So after one family has left, other creatures soon turn up to inspect

the vacant property.

The golden lion marmoset, like all its family, is incurably inquisitive.

They may already have a hole of their own,

but it's always worth inspecting alternative accommodation.

And their curiosity has paid off - the hole contains a meal,

a few cockroaches.

As it approaches the ground, the huge creeper-swathed trunk of the kapok

flares out into buttresses which the tree needs for its stability,

for its roots are very shallow.

The fact is that the forest floor is not a very fertile place.

This is partly because it is so dark, much of the light having been cut off

by the tiers of leaves up in the canopy,

and partly because the torrential rains

wash away much of the nutriment that is in the soil.

So the roots of the kapok tree,

and indeed of any other plant that grows down here,

have to find their sustenance not deep in the soil,

but from up on the surface -

from this, in fact,

from the litter of dead leaves that's continuously falling

down to ground from above.

And the processes which release that sustenance

are in fact very swift. For down here,

there's very little wind, so it's extremely humid.

It's also very warm. And those two factors together

suit the processes of decay very well.

Bacteria and moulds work unceasingly.

Fungi proliferate, spreading their filaments through the litter.

Within days of a leaf landing, they creep all over it,

breaking down its tissues

and returning nutrients it contains back to the soil,

where the roots of the trees, close to the surface, quickly reclaim them.

And as the fungi themselves flourish,

so they put up their spikes and umbrellas,

from which they spread their spores through the jungle.

The most spectacular of all growths on the forest floor

is not a fungus but a parasite.

To find it, you must first discover its host,

a particular species of vine that grows in Sumatra.

If the plant is infected,

then a huge solid bud will periodically emerge from its roots.

When it's swollen to the size of a cabbage, it slowly,

over a period of four days, opens.

Rafflesia. Its body is a network of filaments

that run through the tissues of the vine, absorbing its sap.

It has no stem or leaves of its own.

The only time it becomes visible

is when it puts out these monstrous flowers,

the largest in the world.

FLIES BUZZ

The petals are leathery and covered in raised warty patches.

It gives off a powerful smell which to our noses is revolting,

for it is the stench of rotting flesh.

The local name for it is "bunga banki" - corpse flower.

But that smell is irresistibly attractive to flies

which feed on carrion,

and they flock here. It's they that pollinate the flower.

The seeds are small and probably carried through the jungle

on the hooves of pig or deer

that might tread on the flower inadvertently

and later, elsewhere, kick the bark of another trailing vine stem

and so infect that with another Rafflesia.

The forest floor is littered with the debris of trees - huge fallen trunks,

branches ripped off by a storm

and leaves falling in a steady gentle rain.

It's here that the termites collect their food,

removing it particle by particle

and carrying it away for treatment in their nest.

Their incessant labour, like the work of the fungi,

is a crucial link in the life of the forest, for the termites are bringing

the nutrients in the wood back into circulation.

Few other creatures can eat dead wood and leaves,

but lots can eat termites.

The workers are guarded by soldiers.

This particular kind have nozzles on their heads

from which they can squirt a sticky repellent.

But they can do little against attacks from above.

Spiders sling silken ropes across the marching columns and,

hanging from them, lasso the workers one at a time

and haul them up to be eaten in mid-air.

A whip scorpion. It doesn't have a sting like a true scorpion,

but, then, it scarcely needs it.

The tip of its long antennae tell it where there's prey.

Yet another varied population of creatures

lives within the leaf litter.

Down here it's always moist, so soft-bodied, wet-skinned creatures

can survive very well.

A planarian worm smoothes its way by laying down a carpet of slime.

Peripatus. Halfway between a worm and a millipede, and a hunter of spiders.

Beetles. One of the few creatures apart from termites

that eat rotting wood.

Such inhabitants of the litter are, in turn,

food for hunters from beneath the soil.

A blind, legless, burrowing lizard.

Not all these leaf and wood feeders are defenceless.

This phasmid, a large flightless prickly stick insect,

has a powerful kick.

It gives warning of its strength by rattling its useless wing covers.

The smaller, less savage litter feeders

are collected by little mammals that trot through the leaves,

deftly snapping up a termite here, a beetle there.

In the Madagascar rainforest, a tenrec,

a more distant cousin of the European hedgehog

than its coat of prickles would suggest.

In African forests, the elephant shrew - highly strung, skittish,

prone to career off at suicidal speed if it's startled.

Its long sensitive trunk enables it to investigate

the depths of the leaf litter

with the minimum of noise and disturbance.

But there is one inhabitant of the forest floor

who makes more varied use of more parts of the jungle than any other.

Human beings have lived here for tens of thousands of years,

perfecting the techniques and accumulating the knowledge

that enables them to meet all their needs from the jungle.

The Waorani in Ecuador, or Auca, as they used to be called,

are among the few people left

who have not abandoned any of their ancient skills.

Their favourite fruit is chonta, a kind of palm,

but its trunk is armoured with the most ferocious spines

and impossible to climb.

The Waorani know how to deal with that -

lash a small stick to the end of a pole with a strip of bark,

put a ring of lianas around your ankles

and then climb a smooth-barked cecropia tree

growing alongside the unscalable chonta.

The cecropia doesn't grow next door to the chonta by accident.

The Waorani plant one beside every chonta tree they find,

clearing a space for it so that it can get sufficient sunshine to grow.

Within only a few years, it's stout enough to be climbed.

The Waorani know their individual chonta trees

as well, if not better, than a fruit farmer knows those in his orchard,

and they visit them regularly.

They grow all over the jungle,

and often the people have to make long journeys to collect their fruit

and walk for hours carrying the heavy stems back to their huts.

Chonta can be eaten in all kinds of ways except one - raw.

It has to be cooked.

The Waorani now have a few metal cooking pots but they still make

some from clay, coiled and then baked in an open fire.

Hammocks are woven from palm fibre, cups and basins made from gourds,

and the hut itself from branches thatched with leaves.

The pet parrot eats its chonta raw.

The family are going to get theirs as a kind of alcoholic porridge,

and the cook chews it, adding her own spittle so that it will ferment.

The parrot chicks also take their chonta pre-chewed

from their foster parents' mouths,

just as they would from the beaks of their real parents.

The people traditionally are entirely naked,

except for a string around their waist.

In these temperatures, clothes are not needed for warmth.

But the Waorani take great pride in their appearance

and need little excuse to decorate themselves.

The seeds of the achiote plant, when squashed, produce a vivid red paint.

Black comes from charcoal mixed with the juice of the genipa plant.

Face and body painting will last a long time,

for, like many forest people, the Waorani sweat very little.

In the humid air, sweat doesn't so readily evaporate and cool the body

as it does for people elsewhere,

and the Waoranis' skin doesn't produce it in great quantity.

A vine is the source of that famous poison, curare,

with which the Waorani tip their blowpipe darts.

Scrapings from it are wrapped in leaves

and water poured through the mash to dissolve out the poison.

The darts are made from slivers of palm wood.

An old steel knife has been obtained from outsiders by barter

and is a treasured possession.

But even now the Waorani may do this job with a stone blade

or an animal tooth.

The curare has been boiled down into a sticky paste.

Carefully, each dart is tipped with it

and then put in front of the fire to dry.

Fibres from the seeds of the kapok tree,

deftly twirled round the back end of the dart,

will give it an airtight fit in the barrel of the blowpipe.

In Waorani hands, it's lethally accurate.

Hunters communicate with one another in the forest

by using the buttresses of the giant trees.

Such thumps are audible for miles,

and in forest where you can't see for more than a few yards around you,

sound is much the best form of communication.

VARIOUS ANIMAL CALLS

The jungle animals certainly exploit it

to proclaim their territorial rights and to summon their mates.

VARIOUS ANIMAL CALLS

In each jungle, there's one mammal up in the canopy

which has become the champion singer.

In Madagascar, the indiri lemur, in South America, the howler monkey,

and in south-east Asia, the gibbon.

The siameng, with a huge resonating throat sac to amplify its voice,

has the loudest call of all gibbons.

Families sing to one another across the valleys.

Sound is not so effective beside a thundering waterfall,

so one frog that lives in such a place in Borneo uses sign language.

Tree lizards, up in the branches,

where they can easily see all over their small territory,

use a flag on their throat.

Many birds use both media - sound and vision.

These calls, echoing across the Borneo forest,

are invitations to one of the most spectacular theatrical performances

in any jungle anywhere.

BIRD CALLS

The display will take place on a stage

that has been carefully cleared and cleaned by the dancer.

It's an argus pheasant.

The cock has summoned a hen with his calls

and now he leads her to his display ground.

The immense fans, lined with eyespots,

are the greatly elongated feathers of his wing coverts.

There are no pheasants in South America.

There, the dancers on the jungle floor

come from another family, the cotingas,

and one of them, the cock-of-the-rock,

performs in competitive groups.

As many as 40 male birds assemble in one patch of the forest,

but each has his own cleared arena on the ground beneath him.

The performers squabble among themselves

while they wait for their audience.

And here it is, just one - a single drab female.

The dancers descend, each to his own stage.

The dance itself consists of little more than a few bobs and bounces

in the shafts of sunshine that spotlight the stages,

though there may be squabbles among the performers

during the course of it.

The female may or may not be impressed

by the relative merits of the costumes or the dance steps,

but in some way she makes a selection.

A tap on the back of the winner and he claims his prize.

The jungle is a very stable, unvarying place.

There's no wind down here,

the humidity and the temperature remains very much the same.

Even the length of the days and the nights remains almost the same

throughout the year down here on the equator.

And what's more, it's a very ancient place too.

Mountains get eroded by glaciers within thousands of years,

plains turn into deserts inside centuries,

lakes fill up with mud and become swamps inside decades.

But the jungle is millions of years old.

And that may be an explanation

of one of its most extraordinary characteristics -

the great diversity of animals and plants that are found here.

It's as though this great age has enabled the forces of nature

to produce specialised creatures

to live in every tiny niche in this ancient and stable environment.

Just consider, for example, how many creatures have developed

not just a generalised camouflage but a close and precise impersonation.

A young stick insect looks like a poisonous ant.

Yet when it grows up, it becomes a prickly twig.

A beetle has become a winged seed.

A bug dresses itself in a costume of lichen.

A mantis is a dead leaf...

..a lizard, dappled foliage.

Leaves, twigs, tendrils and stems, some fresh, some green,

some apparently blotched with mould - none vegetable, all animal.

A stump on a branch?

No, a bird on its nest. A potoo.

The fertility of the jungle depends not only on sunshine but on rain,

and nowhere does it fall more abundantly than here in the tropics.

A big storm is preceded by a violent gale, which, for a few minutes,

lashes the tall trees and rocks the canopy.

The huge, heavy drops begin to fall, first slowly

and then in drenching torrents.

In places, the floor of the forest becomes a flood,

sweeping in sheets through the trees down to the rivers.

When the storm has passed,

then the blessings of the water it has brought can be enjoyed.

The jaguar is an excellent swimmer

and seems positively to enjoy doing so,

for it's seldom found far from water.

It actually hunts as it wades,

catching crocodiles and frogs and even fish.

One of the small creatures which certainly doesn't enjoy a soaking

manages to pass the storm in perfect dryness

and is still snug in its remarkable shelter.

The leaf of this heliconia is hanging in an unnaturally protective way.

The creatures lodging beneath

have bitten through the veins along the mid-rib,

so that the two sides flop down around it and keep out the splashes.

It's a pair of white tent-making bats.

The storm has brought water to the thirsty.

It has knocked down valuable fruit for the hungry,

well worth storing for a later date.

But it can also bring death to the aged.

CREAKING

A giant kapok has fallen.

Maybe it had lost one of its huge branches from decay

and was already badly out of balance before the storm.

The great weight of water hanging on its foliage

was finally more than it could carry.

The death of this old tree was the starting gun for a feverish race.

The competitors are the spindly seedlings

mostly buried under this wreckage of branches.

Had this tree not fallen, they would have been doomed to an early death,

because once they had consumed the food in the big seeds

from which they sprouted, there would have not been enough light down here

for them to grow any further.

But this tree fall has changed all that.

The huge rent in the canopy above is both the prize

and the finishing post of the race.

Those seedlings that can grow fast and get up there quickest

will have got their place in the sun,

will spread their branches, flower and set seed,

but the rest will have no chance.

The process is extraordinarily swift.

To begin with, shrubs appear which specialise in open sites like these.

They flower quickly and disperse their seeds

to other temporary clearings,

but in a year or so, the sapling trees have over-topped them.

As they grow higher, some begin to flag.

Eventually, only one or two complete the course to the sunlight,

where they will spread their branches,

so the jungle floor once more becomes darkened by shadow

and the green canopy is again complete.