Millions of years ago,
before man, before the ice ages,
when the world was warm and humid,
forests like these covered ch of the earth.
And it was here, rough eons of geological time,
that a profusion of life evolved.
The remnants of those primordial jungles
are the rain forests of today.
They are home to half of all the animal species on earth.
Yet, in the shady depths of the forest,
there is seldom more than a fleeting glimpse of this abundance.
When they are seen,
the animals are often revealed as strange
and splendid examples of natural perfection and adaptation.
Myriad in their diversity and sometimes bizarre in form,
these creatures give the somber forest
a special mystery and splendor.
Endless rains and high temperatures
create the steamy atmosphere in which rain forests thrive.
These conditions occur now only in a narrow belt around the equator
where forests blanket some three million square miles
of the earth's tropics.
Within this belt
lies the small Central American country of Costa Rica,
which possesses one of the richest natural endowments on earth.
When Christopher Columbus landed here in 1502,
he found a mountainous land of rivers
and forests like those he'd seen ten years earlier in Hispaniola.
Then, in what is perhaps the first description ever of a rain forest,
Columbus wrote:
"Lts lands... are most beautiful...
and filled with trees of a thousand kinds and tall,
and they seem to touch the sky;
and I am told that they never lose their foliage,
as I can understand,
for I saw them as green
and as lovely as they are in Spain in May..."
But it was partly from the early explorers
that some popular misconceptions arose.
For many, the first glimpse of a rain forest
was from the rivers that flowed through them.
The forests seemed impenetrable
a tangled mass of undergrowth through
which a man could only hack a path with difficulty.
But in reality, the dim interior is more open
and usually easy to move about in.
Little light penetrates the dense canopy
and so undergrowth is sparse.
Only a thin layer of leaves covers the ground.
A coral snake searches for a place to drink
and finds enough rainwater in a curled leaf.
The bright bands of color warn predators that it's poisonous.
Below this thin layer of leaves lies the forest soiland a paradox.
For the luxuriant vegetation of a rain forest
is often based on impoverished soil.
The explanation lies in the way the forest recycles its nutrients.
Dead trees and fallen leaves rot quickly,
and their nutrients are rapidly reabsorbed by fungi
and tiny roots near the surface.
The entire system is so efficient that little is lost,
and fully 95 percent of the rain forest's nutrients
are held in the living vegetation,
hardly any in the soil.
To shed its old skin,
the coral snake rubs its body
against rough surfaces in the leaf litter.
A male poisonarrow frog is courting a female.
With his monotonous song,
he will try to entice her
to follow him under a leaf where they'll mate.
The male leads the way.
She follows. Within the shelter of a curled leaf,
she'll lay her eggs, and the male will fertilize them.
She has produced five eggs in a cluster of jelly
and will stay nearby until they're ready to hatch.
Workers from a colony of leafcutting ants
are harvesting leaves to take back to their nests.
With their scissorlike jaws,
they easily cut the leaves to manageable size.
But some skill is needed for the next stage
when the leaf is hoisted into position for the journey ahead.
For some, the problem may be too much help
for others, just a sudden puff of wind.
But they're the exceptions.
For most ants,
it's only the first step in the long trek back to the nest,
which may be 100 yards or more away.
They follow a chemical trail laid down by the workers
that first scouted this tree,
so they seldom go astray.
The leaf fragments that they carry are not for eating.
Instead, they are employed by the ants
in a remarkable system of farming.
The leaves are used to culture the fungus
that is the only food source for the ants and their brood.
Here in the underground garden,
the leaves are cut into much smaller pieces and carefully cleaned
probably to remove any spores
that might contaminate the pure culture.
The leaf edges are chewed to a wet pulp,
and a clear droplet of body fluid
is added to create the perfect foundation
for the precious fungus that sustains the colony.
This is not the work of leafcutter ants.
The insects that create these patterns
are seldom seen during the day.
In daylight, insects are more vulnerable to predators,
so many feed only at night,
leaving their mark everywhere in the understory of the forest.
But some insects are active by day,
and this morpho butterfly is a brilliant target for a jacamar.
Before it can be swallowed, the wings must be removed.
Great agility and keen eyesight make this anole
lizard a formidable predator on small insects.
Nearby, a female is shedding.
Her old skin is too nutritious to be wasted;
she eats every bit of it.
The female is in his territory and by staying,
she shows that she is willing to be courted.
He displays to her by flashing his brilliant dewlap.
A performance like this is both a signal to the female
and proclaims his territory.
The female will remain here now,
and they'll mate frequently over the next few days.
Its body blending perfectly with the leaves,
a praying mantis settles in a patch of sunlight
created by a fallen tree.
When a great tree falls,
a gap is created in the forest canopy.
It is in these sunny spaces that the forest regenerates itself.
The seedlings of most forest trees cannot survive in shade;
to flourish, they need light.
So the competition for space around a fallen tree is intense.
And for every sapling,
there is a clinging vine competing for a place in the sun.
But in this gap,
there's a tree that always has clear growing space around it.
This species of swollenthorn acacia
has evolved a remarkable system of defense.
For as soon as a sapling or vine touches it,
ants that live on the acacia attack the intruder.
They cross onto the touching vine and cut through its leaf stems.
In a short time, their work is done,
and the vine will lose its leaves,
wither, and die.
Most forest trees have evolved poisonous chemicals
in their leaves to stop insects from eating them.
But the acacia is edible,
and would soon be destroyed
were it not for the vigilance of the ants.
Any insect that lands on this acacia
soon learns its errorfor the ants bite and sting viciously.
In return for their protection,
the tree completely supports the ants.
It secretes for them a sugarrich solution,
which they drink from little nectaries between the leaves.
On the tips of some leaves in each acacia,
unique structures are grown especially for the ants.
They are rich in protein and vitamins,
and are taken by the ants to feed their larvae.
It's here within the large hollow thorns of the acacia
that the ants rear their brood.
Some of these larvae will mature into fertile adults with wings,
and fly away to start another colony in a seedling tree.
These young basilisk lizards forage along the river's edge.
They live in the territory of this adult male
who tolerates them and probably fathered them.
But he allows no other adult male to intrude here.
This female is exclusively his.
Flowers are attractive to the leafcutters as well,
and many end up in the fungus gardens.
Spider monkeys move as easily through the canopy
as the puma through the forest's understory.
Towering 100 feet above the forest floor,
the canopy harbors more treedwelling creatures
than any other habitat on earth.
The treetops mingle and interlock to create a selfcontained world;
many of its inhabitants never leave its sunny spaces to venture below.
A threetoed sloth feeds in the hot sun,
while a mother carries her baby
into the cool shade within the canopy.
A "lieinwait" lizard remains perfectly motionless.
It's a strategy that serves it well: By keeping still,
the lizard is overlooked by both predator and prey.
And an unsuspecting victim can be pounced on from above.
Rain forests seldom get less than 100 inches of rain in a year.
Some even exceed 400 inches.
And so, most of the leaves in the humid understory
of the forest are specially adapted to drain water
from their surface as quickly as possible.
If water stays on them,
the leaves may rot or become host to tiny plants that may do damage.
These drip tips ensure that the leaves will dry quickly.
The forest floor can usually absorb rain as it falls.
But when the rains are particularly heavy,
the forest becomes saturated
and the water runs off to flood the surrounding rivers
flushing fallen trees and debris out to sea.
A tide line of rotting vegetation is left on the beach,
and a shy agouti forages among it for fruits.
These paper wasps are drying their nest.
Constructed of wood pulp,
it would soon soak up the rain
if the wasps didn't drink the water and spit it over the edge.
The adults take so much care and trouble,
because in each of the cells is a developing wasp,
and their entire brood could be destroyed by a heavy downpour.
As each larva grows,
the wasps enlarge its cell by adding another layer
of pulp and saliva to the outside rim.
And when the nest begins to warm in the sun,
they cool their brood by rapidly vibrating
their wings to create a current of air.
The eggs of a poisonarrow frog have hatched,
and the female carries two tiny tadpoles on her back.
While they are developing into frogs,
they have to be in water.
She takes them up a tree to a site
she has chosen in a bromeliad plant.
She will deposit them in rainwater held in the bromeliad.
She makes her way down a leaf to a small pool at its base.
And here, she submerges her tadpoles
until they release their grip and leave her back.
The tadpoles will complete their development in this tiny pool.
In six to eight, weeks they'll emerge as frogs
and return to the forest floor.
Army ants are on the move.
They build no permanent nests and
constantly comb the forest for their prey.
This species preys only on the larvae of social insects
and here they attack a nest of paper wasps.
There is nothing the wasps can do.
They abandon their brood to the voracious horde,
which will soon strip the nest of all life.
They take their plunder to a bivouac
on the underside of a fallen log.
Here, by linking special hooks at the ends of their legs,
they form long, hanging chains.
Through sheer numbers,
these strands mesh together to from the living fabric of the nest.
Within the nest, strands of workers interlock
to create chambers for the queen and brood.
At night, the forest teems with a different life.
It's now that most of the leafeating insects emerge.
To survive the ravages of insects,
most plants have evolved toxic compounds that protect their leaves.
But insects in turn have developed immunity to the chemicals.
So together they have evolved, insect and plant,
until now most insects have become such specialized feeders
that they can only eat the leaves of one particular plant,
or only one family of plants.
This harlequin beetle spends most of its life
as a larva concealed within dead wood.
But now as an adult, it emerges to find a mate.
The beetle is host to a resident colony of mites
that finds refuge in the creases and folds of its back.
Also riding on the beetle
are pseudoscorpions that prey on the mites.
Help in the prowerful job
the creases is no chance in the Chigao seem see
A stick spider suspends itself head down
above a leaf on which its prey might walk.
Its web is held by the tips of its four front legs.
Green leaffrogs gather near a forest pool to mate.
The males wait near the water
to intercept the females as they arrive.
Clasping the much larger female,
the male will stay with her now until she has laid her eggs.
She selects a leaf directly above the water,
and as she lays her eggs, the male fertilizes them.
The cateyed snake isn't interested in the frogs.
He is after their eggs.
And as egglaying has been going on for several days,
he will easily find others.
Many snakes are attracted to the pool
when the leaffrogs are laying.
They eat almost all the eggs.
Glass frogs also lay their eggs above water,
in this case a stream,
and the male remains close to the eggs
until they're ready to hatch.
His presence probably deters flies
and other insects that would harm them.
On a rainy night about two weeks after the eggs are laid,
the vigil of the male ends
when the emerging tadpoles drop into the stream below.
But the frogs do not always manage
to lay their eggs directly above the water.
However, the tadpoles are specially equipped with reflexes
that help them cope with this situation.
The first rays of sun warm the forest
and a mist rises up the great mountain mass
that divides Costa Rica,
separating the forests of the Atlantic coast
from those of the Pacific.
High in these mountains,
the forest receives moisture
from direct contact with the clouds,
and the vegetation changes imperceptibly.
Many of the creatures found here
can live only at these cooler heights.
And it's here at the very top of the mountain
that a rare mating ritual occurs.
It takes place only during the few days of the year
when contact of cloud and forest is at its greatest
when enough water has collected to form the few small pools
in which golden toads lay their eggs.
These toads occupy an area of mountaintop
no greater than one square mile.
They have been found nowhere else on earth.
The golden males gather at these pools
and fight for possession of one of the drab females.
Once firmly established on her back,
a male is usually secure in his conquest
and can easily repel any further challenge.
Long strings of eggs are laid in the tiny pool,
and if the misty weather persists long enough to maintain the pool,
another generation of golden toads will be produced.
Bellbirds announce their territories
from the tops of the tallest trees.
A pair of Resplendent Quetzals are digging out a nest in a dead tree.
The males are considered
the most beautiful birds in the western Hemisphere.
The ancient Mayas and Aztecs so revered
the quetzal that only royalty and nobility
were allowed to wear the magnificent feathers
in their ceremonial costumes.
To kill the bird was a crime;
they were simply caught
and released after their long plumes had been plucked.
But the forests are going.
At the present rate of destruction,
most countries will lose their rain forests within our lifetime.
And with the forests will go hundreds of thousands of unique
and irreplaceable life forms that can survive nowhere else.
Many will become extinct even
before they have been described by science.
Their importance to nature's balance
and their possible contribution
to human welfare will never be known.
But at last,
some countries are beginning to realize that
rain forests justify their existence simply by being there.
And tiny Costa Rica, by its example,
has become a world leader in conservation.
One quarter of its land is given some measure of protection,
and a full eight percent
is permanently protected in national parks.
If other nations will follow Costa Rica's example,
there is hope.
But it is a race against time,
because in the hour it has taken to view this film,
some 3,000 acres of the world's rain forest have been destroyed.