Original subtitles

Powerful forces make the islands between Australia and Asia

among the biologically richest on Earth.

One force rules above all others,

its daily rhythm so powerful, all life must adapt.

It turns rain forest trees into towering giants,

and others into stealthy killers.

Strange creatures hide in its shadows,

while others bask in its life-giving energy.

It's the awesome power of the tropical sun.

Life here follows a daily rhythm,

millions of years in the making.

A constant cycle driven by a celestial force.

Families of gibbons declare their ownership

of the treetops through song.

Sound travels farthest in the still, cool air of dawn.

The song of the gibbon heralds

the most powerful force to rule these ancient rain forests...

the tropical sun.

These islands stretch along the equator...

...with the sun rising at the same time every day.

Part of a timeless cycle.

The plants and animals of the rain forest

depend on this one force more than any other.

The trees, subjects of the sun, need its energy to grow.

Already, billions of leaves release water vapor

as they trap its life-giving rays.

The sun will grow ever more powerful as the day advances.

Beneath the canopy,

the early morning is a busy time.

The sun's green realm is so complex

that this young Sumatran orangutan

will spend as many as nine years learning from his mother,

the longest childhood of any primate other than ourselves.

An important day of lessons is just getting started.

Sumatran orangutans are the most arboreal of the great apes.

This newborn will spend his whole life in the treetops.

He'll need to learn how to navigate safely.

Mom moves only one limb at a time.

It gives her the balance to walk the trickiest of tightropes.

Orangutans are unique among primates

in the way they move between trees.

Instead of jumping, she takes her time,

using her weight to bridge gaps.

In their years together, mom will teach him

all about life beneath the sway of the sun...

...for theirs is a complex world,

one filled with giants.

Here, a single family of trees dominates,

and it has for millions of years...

the dipterocarps.

There are hundreds of species,

and in places, they dominate the canopy.

Like most trees, the fight for life

begins in the forest's dark depths.

As morning wears on,

sunlight penetrates the shadows, but fleetingly.

Down here, plants have only minutes each day

to extract what energy they can.

Young dipterocarps play a waiting game.

They can survive many years hardly growing,

waiting for a gap to open up in the canopy

to give them their moment in the sun.

These tall trees can stretch more than 150 feet into the sky.

To outcompete other trees, they put more of their efforts

into growing their enormous trunks.

Dipterocarps are the tallest tropical trees on Earth,

powered by competition for the mighty sun.

The first branches appear only toward the very top,

maximizing the exposure of every leaf to the sun's energy.

Such is the battle for light

that the majority of life is found up here in the canopy.

But to live in a forest of giant trees,

animals require extraordinary adaptations.

While hot-blooded mammals like Sumatran orangutans rise early,

this reptile is spending his morning basking in the sun.

This is the Draco lizard.

His dark skin helps absorb more of the sun's energy.

But warming up has a downside.

He's a sitting target.

Paradise tree snakes like to eat Draco lizards.

Time for a speedy exit.

The trouble is, the crowns of the giant trees

all stand at different heights.

There can be huge gaps between them.

It's easy to get cornered up here.

But not for the Draco.

He can fly to safety...

...though the chase doesn't end there.

In these forests, even snakes fly.

Wildlife here have brilliant ways of surviving

among the giant dipterocarps.

But they're not alone

when it comes to clever survival tactics.

In the struggle to compete for sunlight,

one rain forest plant has evolved into a stealthy killer.

It begins life high among the dipterocarp's branches.

But it needs more nutrients than can be found here.

While most trees grow toward the light,

this one reaches into the darkness.

Its roots travel downward more than 150 feet...

...a journey that may take years.

Right now, there's no obvious threat to the host.

But once the roots penetrate the soil, everything changes.

Fueled by water and nutrients from the ground,

the roots thicken.

The plant sends down more and more roots.

Wherever they touch, they fuse together.

By now, the dipterocarp's fate is sealed.

It's in the grip of a strangler fig.

Over the years, the roots choke the host.

Outcompeted and unable to grow, the giant is defeated.

This will be its tomb.

Years later, a few shards of rotting wood

are the only clues that a huge tree once stood here.

The strangler, supported by its own roots,

stands over the dipterocarp's decaying remains...

...a victor in the eternal struggle for the sun's energy.

A fruiting fig tree draws in animals from across the forest.

All who come to dine here

will provide a vital service for the strangler

by helping spread its seed through the canopy.

A single tree produces as much as a half a million fruits...

...yet so many animals visit the banquet

that the tree can be stripped bare within a week or two.

Making the most of this food source

is a crucial lesson for any young orangutan.

But this morning, the chance to feed is coming to an end.

It's approaching midday.

In the exposed high canopy,

the temperature is already well over 85 degrees.

The sun is beginning to overwhelm.

As it grows stronger, the trees risk losing too much water.

They begin to shut down.

Now directly overhead,

the all-powerful sun beats down on the ancient rain forest.

Its subjects must protect themselves from its might.

With the sun directly overhead

and bearing down mercilessly on the rain forest,

activity comes to a stop.

Orangutans head below the canopy in search of relief.

They retreat to their nests to wait out the heat.

The day's lessons are now on hold.

Everyone needs to conserve their energy during these hours,

including the area's biggest male.

Despite the conditions,

one female is still up and about.

She seems interested in the male.

Orangutans are largely solitary animals.

And encounters like this one are rare.

The male seems to have only one thing on his mind...

that's keeping cool.

The sun draws up so much water

that as afternoon arrives, clouds form.

They build and build,

till they burst.

Four inches of rain can fall in just two hours.

One remarkable plant turns rainfall to its advantage.

Gracilis is a carnivore that preys on insects.

It lures victims with nectar,

offered on the underside of its lid.

It's an easy meal for a hungry ant,

but those who visit risk their lives.

There's enough grip to hang on, but only just.

It takes one direct hit.

There's no escape.

The ant will slowly dissolve.

Gracilis turn downpours into an advantage,

but others are at their best when the rains subside.

Sun bears sit out the heaviest of a rain forest deluge.

When the cooler afternoon hours arrive,

they are at their most active.

This female works hard to find her favorite insects.

It takes all her strength to rip open a fallen dipterocarp.

But there are rich rewards inside.

The afternoon rains lower the temperature,

giving sun bears a chance to feed.

For others, all this water presents a unique challenge.

As streams swell across the rain forest,

a miniature world springs to life.

In the late afternoon, male rock frogs begin to gather.

They are here to compete for a mate.

The trouble is, being this tiny

makes it hard to be heard above a waterfall...

...so rock frogs vary the duration, pitch, and volume

of their calls.

A decent effort, but this much noise requires drastic action.

By varying their calls and waving to each other,

they have a unique solution

to life as a tiny frog in a noisy world.

The males are here hoping to attract a mate...

...though her arrival can push things over the edge.

Despite a sophisticated means of communication,

it quickly descends into a wrestling match.

Species here have come up with all sorts of solutions

to deal with the regular rains.

It's part of an ancient daily pattern,

driven by the tropical sun.

Over millions of years,

its energy has created a realm like no other,

all because it rules with such extraordinary consistency.

The islands stretch from Australia to Asia,

along the equator.

Day length changes very little.

Some of these forests experience

the least seasonal change of any habitat on Earth,

which poses a unique problem.

The trees have no predictable cues to time their breeding.

Instead, they have to rely on infrequent droughts.

It could be every few years or once a decade,

but drought triggers the trees to reproduce.

The dipterocarps lead the charge,

each tree dropping thousands of winged seeds.

And ready to sweep the ground clean of seeds

are these forest denizens.

Bearded pigs love the seeds of the dipterocarp trees.

During the glut, most seeds are eaten or destroyed.

But by dropping so many at once, the giant trees ensure

that at least some escape the pigs' hungry jaws.

All animals have to take advantage

of these predictable times of plenty.

And it's not just the dipterocarps.

Many trees here bear fruit only every few years.

Orangutans aren't limited

to scooping a meal off the forest floor.

They're equipped to go straight to the source.

In the years spent with mom,

a youngster learns where to find fruit

before setting out on his own.

It's a unique paradox of some of these rain forests

that despite the abundance of life,

there are long spells when fruit is scarce.

Mother knows only too well

that she can't rely on fruit alone to get by.

Hidden in the treetops is a rich supply of ants.

You just need to know where to find them.

To thrive in these forests

is all about learning what to eat, where, and when.

Today's lessons will soon be over.

The subjects of the sun must prepare for the coming night...

...for there is another realm here.

It's one where creatures hide away from the sun's power

and have evolved to live shrouded in darkness.

The transition is marked by an extraordinary sound.

Right on cue, the call of the 6 o'clock cicada.

Night here is a shadowing sanctuary of freaks.

Fungi glow with a soft light

to lure insects that will disperse their spores.

With just the light of the moon to see by,

one denizen of the darkness undergoes a bizarre change...

Deinopsis.

Her two large eyes are truly astonishing.

Right now they're changing.

Cells inside them build to form

an extremely light-sensitive membrane,

essential to the way she hunts.

Her web is unlike any other,

a Velcro-like net built to snare passing prey.

Preparations complete, she waits.

She binds her quarry in silk

before slowly sucking the life from it.

When dawn returns,

the membrane inside her eyes will be re-absorbed,

a feat she repeats night after night after night.

Deinopsis isn't the only creature

whose bizarre eyes allow it to thrive in this world of shadows.

The tangled roots of the strangler fig

are home to a carnivorous hunter.

Each of the tarsier's sensitive eyes

is the same size and weight as its brain,

so large, they can't move.

But the tarsier can rotate its head 180 degrees.

And its huge ears can move independently.

The tarsier is built to detect

the smallest movement in the dark.

Higher up in this world of shadows,

an even more bizarre creature inhabits the rain forest canopy.

Like the paradise tree snake and Draco,

the colugo's life is dictated by the giant trees.

To avoid climbing up and down their trunks,

it glides across the forest.

The underside of its gliding membrane has no fur,

which reduces drag.

A cloak stretching from the shoulders to the tail,

even between its fingertips...

...makes it as large as physically possible.

Gliding from tree to tree saves a lot of time.

Colugos search out young leaves and flowers.

A freakish cast inhabits this world without sunlight,

each with their own extraordinary adaptations.

But they, too, abide by the sun's rule.

As dawn approaches, they retreat to the shadows.

The colugo depends on its mottled fur for camouflage.

A distant call proclaims the coming day.

And as it does at the same time

every morning here in the tropics,

the sun returns to rule over the ancient rain forests.

The islands between Australia and Asia

are among the biologically richest on Earth.

Erupting volcanoes drive the evolution

of the beautiful and the bizarre.

Along the shores and in the sea,

the moon holds sway over a mysterious world.

And in its forests, the sun's daily rule

sustains an astonishing profusion of life.

Nature's most powerful forces... the earth, sun, and moon...

make this a place like no other.

Forged over millions of years, these ancient islands

are home to some of the greatest assemblage of life

on the planet.