Original subtitles

[Mysterious music]

[Narrator] The wildest forests of them all

see nature at her most competitive.

Here, trees recruit their own private armies.

[Monkeys vocalising]

[Narrator] And plants have the power to beguile.

Lumbering giants become gentle gardeners.

And sloths carry a whole world on their shoulders.

Everyone plays a part in the story of our Tropical forests.

[Animal sounds]

Take a journey

through our planet's kaleidoscope of forest realms.

From the frozen boreal in the north,

to the tropical jungles that hug our equator...

from mountain peaks...

to the ocean depths...

Marvel at the magic...

and drama...

that unfolds, as we reveal...

the secrets of the Enchanted forests.

Tropical forests are the metropolis of the natural world.

A diverse habitat,

where the destinies of millions of species are intertwined.

But there is one creature

who has such a deep connection to his forest surroundings,

he is growing his own mini forest on his back.

This three-toed sloth

just wants to hang out and watch the world go by.

He may look like he is moving in slow motion

but that's just his style.

Sloths hold the record for the slowest metabolism of any mammal

so he simply doesn't have the energy to rush.

When you live in such harmony with the forest,

plants don't just grow around you, they grow on you.

His fur, moist from the constant rain,

is covered in algae and fungus,

which in turn attracts colonies of hitch hiking bugs.

[Whimsical music]

But he doesn't seem to mind.

In fact, it could be part of his plan.

There's even one insect

that the sloth is prepared to risk his life for.

Meet the sloth moth.

The sloth's dank jacket is the only place in the world

where these moths live, feed, and even mate.

But to complete their life cycle,

the moths need one favor from their host,

one that could jeopardize his own safety.

Once a week he gets the urge to answer the call of nature.

So down he goes.

[Birds chirping]

[Soft music]

The forest floor is like an alien landscape.

Full of prying eyes.

There's no reason he couldn't 'long drop'

from the safety of the branches above.

It seems he takes this risk

purely for the benefit of his moth friends.

His dung is the perfect place for his moths to lay their eggs.

When the eggs hatch,

tiny moths fly back up to the canopy,

to find their own laid back host.

But what does the sloth get out of it?

It's recently been discovered

that the moth's early diet of dung

brings a dose of nitrogen to his fur.

This fertilizes his onboard algae garden,

which he can keep in reserve for whenever he wants a quick snack.

It might not give him a burst of energy,

but it makes the effort

of descending to the forest floor worth it.

[Upbeat music]

The sloth and his moths make up their own mini ecosystem.

Made possible by his slow and accommodating nature

and the forest's moist environment

that encourages everything to grow...

... even on the animals themselves.

Warm temperatures and high rainfall

allow most rainforest trees to stay green all year round.

[Birds squawk]

It is also what gives these forests

their steamy character.

And the trees themselves play a big part

in generating that much moisture...

... by breathing out water.

[Thunder clapping]

With such a dense canopy,

only a portion of the rains that fall here

ever reach the ground.

[Soft music]

But what is left gets sucked up through the tree,

before being released once again as vapor,

through tiny pores in the underside of the leaves.

Within the forest, this moisture is constantly being recycled.

One water vapor molecule

can travel through a tree up to seven times.

But the moisture that escapes the canopy

and rises into the atmosphere, can have a far reaching impact.

In a single day, the trees of the Amazon rainforest

pump out 20 billion tons of moisture.

These rivers in the sky can influence global climate,

causing wind patterns to shift,

and affecting rainfall as far away as the American Midwest.

Our tropical forests act as the Earth's biological pump -

circulating and maintaining

the balance of our planet's water cycle.

On the island of Madagascar,

there is a tropical forest that is positively... otherworldly.

Here, imposing trees stand guard...

... protecting the spirits of the canopy.

[Strange animals vocalising]

These are the haunting calls that roam the forest.

In fact, they are made by this guy... the indri.

[Indris calling]

The largest, and one of the loudest, species of lemur.

Unusually for primates,

in lemur families it's the females who rule.

[Indris calling]

So after a dawn chorus of territorial howling,

its Mum who decides where they go to find food.

She and her baby daughter

get the pick of all the tastiest leaves in the canopy.

Whereas Dad... does not.

Given the choice, Indris prefer the very freshest leaves.

And there are plenty on offer as long as they keep moving.

But, there's a problem...

Unlike their distant monkey cousins,

their arms simply aren't designed

for swinging between branches.

Nor do they have prehensile tails to hang from.

But what they do have is a strong grip

and a flair for the dramatic.

[narrator] At this age, the baby just needs to cling on,

but in a few months she'll be too big to be carried.

Every leap of faith has to start somewhere.

Despite what their territorial calls might claim,

the indri do not rule this forest.

Far from it.

They share it with a hundred other species of lemur!

Madagascar became an island 150 million years ago.

Since then, it's been following its own evolutionary path.

Instead of one species of lemur

fighting for dominance over all the others,

they found an alternative solution.

Each species evolved to specialize

in one particular food source within the forest.

And the huge variety of trees and plants here,

meant this tropical forest

could cater to a whole assortment of tastes.

The indri stuck with their leafy diet,

so the brown lemurs cornered the market in toxic fruit.

They can happily eat the fruit and leaves

that contain high levels of tannins -

an astringent acid most other lemurs simply can't tolerate.

Whilst the black and white ruffed lemurs

have a taste for nectar.

With thin pointed snouts and extra long tongues,

they can reach the sweet treats that other lemurs can't.

Bamboo lemurs, on the other hand,

have developed an inbuilt antidote

that neutralizes the poison, cyanide, found in bamboo.

Meaning they are the only lemurs

that can eat as much as they like without killing themselves.

[Aye-aye squeaking]

And then there is the aye-aye, the weirdest of them all.

These are the forest's night stalkers.

Their ghoulish appearance is matched only

by their curious technique

for finding their preferred food.

Using a freakishly long, vampiric middle finger,

they tap out a rhythm at up to eight beats per second,

to locate insects and grubs,

which they then extract using their witchy digit.

[Whimsical music]

Between their incredible powers of adaptation

and a rainforest banquet to choose from,

each lemur species has found its own special niche.

[Lemurs calling]

However weird and wonderful that may be.

Whilst they are getting their leaves chomped

and branches climbed,

tropical rainforests are quietly and steadfastly

keeping us all alive...

Cleaning the air that we breathe and the water we drink.

[Enchanting music]

As they turn sunlight into food,

they remove harmful carbon from our atmosphere

and release pure oxygen back into it.

They filter pollutants out of the water cycle,

whilst replenishing our freshwater stores.

And they can literally cure us.

As much as a quarter of all western medicines

are derived from rainforest plants,

some treating critical diseases such as malaria,

leukemia and Parkinsons.

All life is connected to the forests on this planet.

And right now, they need all the help they can get

to keep thriving under immense pressure.

[narrator] An unlikely alliance can be the key to success

in a tropical forest.

But when a monkey teams up with a murderous tree,

it can lead to both death and life.

[Soft dramatic music]

[Monkey growling]

The aptly named Howler monkeys rule these treetops.

This alpha male uses his guttural calls

to ward off potential foes.

[Monkeys howling]

He and his family

are inadvertently aiding and abetting a known killer.

To get a foothold in this crowded forest

a tree must also find its own niche.

And the fig tree has a unique approach.

But it needs the howler monkeys' help.

Fig trees fruit sporadically all year round,

so somewhere in the forest

there will be juicy, sweet figs to lure in a willing accomplice.

[Ominous music]

Once the howler monkeys have filled up on fig, they move on.

As the seeds pass through their system,

they are "deposited" far across the forest,

high up in the canopy,

onto the branches of other unsuspecting trees.

Here, the seed sprouts...

slowly growing in the light...

and leaching from its host

whilst it sends its roots downwards

towards the forest floor.

Now fueled by both the sun and the soil,

it gets a stranglehold on its victim.

[Sombre music]

The fig's iron grip

can squeeze the life out of even the mightiest of trees.

Until the only evidence left...

is the hollow outline of the tree that once stood here.

A slow motion murder has been committed,

and everyone in the forest knows whodunnit.

But the witnesses are keeping quiet.

They stand to gain the most from the crime.

Once matured,

the fig tree becomes a towering pillar of the forest community.

And restyles itself as a provider -

a veritable primate grocery store.

Squirrel and Woolly monkeys feast on the protein rich fruit

whilst night monkeys make a home from its twisted roots.

These boreholes are the work of the world's smallest monkey -

the pygmy marmoset.

So tiny, they could fit into the palm of your hand...

But with teeth strong enough to gnaw through the fig's bark,

to reach the sugar-rich sap hidden below.

Or if it prefers,

a buffet of insects found amongst the branches.

[Inquisitive music]

Through its primate partnership, the fig tree has become

one of the most successful trees on Earth.

With over 150 species,

the strangler fig provides for more animals

than any other tropical tree.

They may have gotten away with murder,

but now they are helping to feed the entire forest.

[Distant monkeys howling]

The path to tropical forest reproduction

doesn't always demand such devious plotting.

Nature has a catalogue of inventive ways

to cultivate its seeds.

Some so clever, they can even water themselves.

Seeds, pollen and spores are designed to catch the wind,

or float to their new destination.

Even a fungus must leave its dark underworld

and enter the limelight when it is time to reproduce.

And they too need their offspring to travel.

The mushroom serves as their version of a flower.

It requires moisture in the air

to trigger the release of its microscopic spores.

The mushroom then releases billions of these particles,

which are swept up by the air currents.

As the spores rise,

they collide with the dense water vapor

produced by the trees.

Which accumulates around each particle,

and condenses, forming clouds.

[Fantastical music]

With trillions of these invisible interactions

happening above the forest canopy,

when fungal spores and trees come together...

... rain is born.

[Thunder clapping]

It's an ingenious self watering system.

Throughout the forest,

mushrooms release spores that help produce rain,

which encourages even more mushrooms to grow!

[Rain pouring and thunder clapping]

With torrential downpours like these,

a good shelter can be priceless.

And the most accomplished homebuilders in these trees

aren't the industrious birds,

but tiny insects using the power of the hive mind.

Most ant homes are built on the forest floor.

But they're prone to flooding, so these smart weaver ants

are heading for the canopy.

[Upbeat music]

But with half a million individuals in a colony,

these ants don't just need a home,

they need a property empire.

The all-female crew of construction workers

start by finding the right tree.

Supple, elliptical shaped leaves

make the best building materials.

[Inspirational music]

The ants grip the edge

with their vice-like mandibles,

maneuvering them into a framework.

For wider gaps, the ants form living chains,

up to 12 individuals long,

to draw the leaf edges into position.

The task of fixing the leaves together

falls to the youngest members of the ant colony

By gently tapping the heads of the larvae,

the worker ants are able to extract a fine silk,

ideal for stitching the whole structure together.

[Enchanting music]

It may take hundreds of leaves to make a suitable home.

But the finished property is an engineering masterpiece.

It's both waterproof and warm.

Heated by the sun

to keep these cold blooded creatures ready for action.

Like all construction workers, these ants are fueled by food.

And for that they turn to their non-building colleagues.

The smaller ants of the colony

have exploited a different vocation...

Farming.

These aphids are the weaver ants' livestock.

They keep them in tightly packed groups,

with a constant supply of leaves to eat.

When the aphids feast on the leaf sap,

they produce a sugary sweet honeydew.

And a gentle drumming by the ant's antennae

releases this precious elixir -

the insect version of an energy drink.

[Enchanting music]

The aphids appear to be willing hostages.

With food,

shelter,

and half a million bodyguards.

What more could a small, defenseless aphid want?

Not every relationship is as cordial as this one.

In a tropical jungle,

beguiling propositions are often laced with deadly intent.

From lethal infusions...

or love potions...

the world's tropical forests boast an impressive array

of poisonous plants,

and a host of creatures

that use them to bolster their own defenses.

These tiny colorful jewels

are some of the most toxic creatures on Earth.

And the most deadly of all is the golden dart frog.

Don't be taken in by his beauty,

his vibrant colors are a sign

that he oozes poison through his skin.

He extracts this noxious mix of chemicals from the food chain.

From plant, to insect, to frog.

His concentrated poison is so potent

it can kill a person in just ten minutes.

While some like to shout about their toxic nature,

others go about things a little more subtly...

[Military music]

This unassuming millipede might not look toxic,

but he secretes a chemical called benzoquinone -

a powerful irritant to deter any predators.

In Madagascar's tropical rainforests,

rather than eat the millipede,

some lemurs rub their juices on their fur

as it makes an excellent insect repellent!

But these tonics aren't only used to repel.

In fact, they are often used to do the opposite.

[Bees buzzing]

This male orchid bee is collecting scented oils

to mix into a fragrant love potion,

so potent, any passing ladies will be instantly seduced.

[Enchanting music]

In other parts of the tropics, using a seductive chemical

can cause less of a crush, more of an obsession.

On the surface, Providencia off the coast of Colombia,

looks like a tropical island paradise.

[Distant birds singing]

But look closer, and all is not as it seems.

Here, sea creatures live in the mountains,

trees have the power to cast spells,

and zombies roam the woodlands.

[Sinister music]

[narrator] Now, as the rainy season approaches,

one of the island's hilltop residents

is about to embark on an epic journey.

[Inquisitive music]

This tiny crab is being called back to the ocean to give birth.

Although she is now a land creature, this invisible tie

is a remnant of a long lost life beneath the waves.

But to get there, she must travel down the mountain

and run a deadly gauntlet through the forest.

The next generation of black land crabs

depend on her 85,000 fertilized eggs

reaching their destination.

Even though she begins her journey alone.

Across the island, thousands of female land crabs

are starting similar quests.

Together, they will face many challenges.

But none greater than the deep, dark forest.

At first, the dense tree cover provides some much needed shade

for these expectant mothers.

But not all of the forest is quite so welcoming.

[Ominous music]

Small but intimidating,

these Bullhorn acacia trees are laced with weapons.

But it's not the thorns the crabs need to worry about,

it's what patrols between them.

These are acacia ants.

And they are under the bullhorn's malicious spell.

Lured in by the tree's sweet nectar, the ants moved in,

making their homes inside the acacia's thorns.

But... it was a trap.

The nectar contains a special enzyme,

which, once tasted,

prevents the ants digesting food from anywhere else.

Once they drink it, the ants can never leave.

So, now the acacia has its own loyal, security force

to protect its leaves from being eaten.

[Sinister music]

The crabs must face down the zombie ant army

to reach their destination.

The call of the ocean is too strong to turn back now.

One crab makes her move.

It's a suicide mission.

Although she poses absolutely no harm to the tree,

the ants are brainwashed into attacking anything

that approaches their precious master.

By exploiting the chinks in her armor,

they sting her into submission.

Using their own venom to paralyze her,

and slowly dissolve her body.

As the horror plays out, our mother slips through the melee.

She must press on to the coast...

Soon, the dry tropical forest gives way to coastal mangroves.

A seemingly impenetrable maze of roots and spikes.

But it's more friendly here...

and a sign that the end is in sight.

Under cover of darkness,

she and the other survivors reach the sea.

Exhausted, she releases her precious brood into the surf.

She made it.

And has given the best start possible

to her 85,000 children.

Job done, she must return home, through the forest.

Once again, she'll make the most of its refuge,

and navigate its dangers.

And if she's lucky, she'll get to do it all again, next year.

As for the bullhorn acacia,

it will continue to wield power over its zombie army.

But only for so long.

Once the enslaved ant queen dies,

so will her colony.

And the acacia, left powerless and vulnerable,

will die too.

[Creatures chattering]

In this most competitive of forests,

everyone must find their path.

For some, coercion is the key to their success

but for many others,

it's collaboration and pure hard work.

Life working in harmony

to sustain these enchanted tropical realms.