Original subtitles

Rush hour.

It's the same all over.

You gotta get where you're going the fastest way you can.

In our busy world,

nature has been banished to the shadows.

But here, in Nepal, the backstreets will only get you so far.

So when you're forced to hit the main drag,

you can either get snarled up in traffic...

...or create your own lane.

This defiant commuter is doing what his kind have always done...

making the nightly migration between feeding grounds.

And if today the savanna has become a suburb,

well, that's not gonna stop him.

Faced with our crazy world, nature strives to find a way through.

And by doing so, each of these determined rhinos

weaves its own tiny thread into a vast web of life.

A living network that spans our entire world.

It connects every living being.

And now, for the first time, we're gonna reveal how.

From the densest forests...

to the deepest oceans.

The fiercest skies...

to the hottest deserts.

This hidden network links the wonders of life

to the great forces of our planet...

keeping our whole world alive.

And even when we disrupt these vital connections...

...nature fights on.

This is the wondrous untold story of the most powerful force on Earth.

Life itself.

Unlock its secrets,

and we'll discover how there could be a brighter future for us all...

on our interconnected living world.

You can pick up a thread of nature's network

anywhere you care to look,

even in the wilds of the frozen north.

She may not know it,

but this newborn reindeer has a vital role ahead of her.

She just has to survive long enough to play her part.

The strongest possible bond with her mother will help.

But first, she will need to master her most important survival tool.

Her legs.

She is a natural-born athlete.

Speed, endurance, she's got it all.

Or she will have when she finds her feet.

Until then, the safest place for a sprinter-in-training

is literally under her mother's feet.

Because eagle eyes are watching...

...waiting for her to stray.

Mom has her back this time.

But the sooner she can get those legs working,

the better her chances.

The calf will find safety joining the herd.

And it's together that these animals make an impact

that's felt far beyond the Arctic.

But only if they're kept on their toes.

Wolves.

Out on the plains,

this herd can spot danger approaching

and can do what they were born to do.

In the open, they can hit top speed.

But among the trees, deep snow bogs them down.

Lucky for them, it's even harder work for shorter legs.

Breaking for open ground means better footing.

And the skittish herd can once again keep a watchful eye on their pursuers.

The Arctic is a tough place to survive,

even for a world-class runner.

But this never-ending dance of predator and prey

ultimately connects to us all.

As the calf and her herd graze on the grass and scrub...

they trim it back,

which allows snow to settle unbroken.

While the predators keep the herds on the move,

spreading their grazing work far and wide.

Together they help create uninterrupted blankets of snow,

turning these white plains into a vast cosmic mirror...

which can reflect up to 85% of the Sun's heat back into space.

We need the Arctic to stay frozen to help stabilize our climate,

making the entire planet more habitable for us all.

And this astonishing cooling system

helps set off another physical chain of events...

that plunges to the depths of our oceans.

Because just off the coast, the sea is freezing.

Ice crystals rise to the surface...

forcing denser seawater to plummet to the seabed...

and warmer surface waters to flood in to replace it.

It's the start of a gigantic circulatory system.

A pump that drives sea currents on a thousand-year round trip

connecting every ocean on Earth.

Where there are currents...

there's life.

Nowhere more so than on a tropical coral reef.

A quarter of all known marine species live on reefs like these.

And a billion of us humans depend on them for our food,

livelihoods, and protection.

Even here in the currents around the reef,

the same rules apply...

for the hunters and the hunted.

The trick is to stay ahead of the competition...

any way you can.

These cuttlefish eggs were hidden in the rocks by their mother.

The trouble is, they soon turn see-through.

So the tiny embryos must stay stock-still to avoid being...

Oh. There's always one.

No bigger than a peanut, this precocious youngster

is already enthralled by the reef around him.

He'll only live for a year,

so he seems determined to learn as much as he can,

as fast as he can.

But his exuberance is attracting attention.

A hungry mantis shrimp with the sharpest eyes on the reef.

He likes his eggs soft in the middle.

But junior is already one step ahead.

Now you see me...

now you don't.

But not everyone is gonna fall for that ruse.

Epaulette sharks can sense the electrical current

given off by their next meal.

And the baby's heartbeat is blaring out like a car alarm.

At the last second, he somehow knows...

...to kill the switch.

Holding his breath and slowing down his three hearts

to disappear once more.

All this eager student needs now

is a grown-up to teach him how to catch his dinner.

It's enough to make a wannabe hunter burst.

Graduating from egg school gives him the best start in life.

He will now feast

on whatever opportunities the currents bring.

Tiny critters riding the watery superhighway

from reef to distant reef.

Spreading new life and new hope

for the future of these underwater wonders.

From a baby reindeer who helps power the ocean's heartbeat

via a tropical reef,

the network of ocean currents connects both poles

as it continues all the way to Antarctica.

Freezing temperatures supercharge the ocean's pulse...

...pumping seawater northwards once more...

where the most powerful currents rejuvenate life...

in places you'd least expect.

During the dry season in Africa's Kalahari Desert,

everyone is struggling to beat the heat.

Yet, even here,

nature's network has a way of providing exactly what life needs to flourish.

All because, hundreds of miles away,

an icy Atlantic current meets hot desert air.

Thick fog blows inland.

Thunderclouds billow up over the highlands

where they perform nature's own alchemy.

Each bolt of lightning is so powerful...

it splits molecules in the air...

creating nitrates,

a liquid fertilizer essential for the growth of every plant on Earth.

These nutrients rain down and cascade south...

crossing hundreds of miles of Southern Africa...

until they pour into the Okavango Delta...

transforming the parched Kalahari into one of nature's greatest oases...

triggering an explosion of new growth

in the once barren desert.

But while a connection to a distant ocean provides the waters...

it is down to the locals to create a neighborhood where everyone can benefit.

Heavyweight engineers bulldoze their way through the vegetation...

...creating networks of flowing channels...

that connect pools and watering holes...

allowing the rich waters to spread further afield.

Meaning, no one misses out.

And for this family of leisure-loving hippos...

it's pool party season.

They've got first dibs on the best bathing spot in the area.

But Dad can't kick back completely.

Keeping hold of this pool and his harem of breeding females

is not gonna be easy.

Both are hot property for young bulls looking to start their own family.

For the father,

this interloper is about as welcome as a Band-Aid in a hot tub.

Dad warns him to back off.

Fighting a two-ton rival would be exhausting.

It could also be deadly.

But if the rogue male steps into his pool,

Dad has a simple choice.

Lose his family...

or fight.

Dad may have to see off many more challengers

before the season is over.

But for now, victory deserves a lap of celebration.

Yeah. Still got it.

All this frolicking and fighting helps to prolong the party season.

It stirs the waters and stops the pools from stagnating.

So even as the flood begins to subside,

their fellow landscape engineers

can be sure that hippo-flavored water is safe to drink.

Just a few months on...

the riches of the flood disappear.

And the bulldozers bring what food is left...

...down to earth.

But even this demolition dinner

sets off a chain reaction

that sends ripples far beyond the desert...

by paving the way for another natural phenomenon.

Fire.

Dead wood fuels seasonal bushfires that rejuvenate the savanna.

And in these flames, a new thread in the vast web of life begins...

with a link that connects continents.

As the brush and soil burn,

microscopic nutrients are released from their earthbound existence.

They rise up with the smoke...

to meet the clouds.

High in the atmosphere,

plumes of phosphorus speed their way through wind currents and weather systems.

Fertilizers carried all the way across the Atlantic...

to the skies of South America...

where their magic rains down...

over the mighty Amazon rainforest.

Remarkably, half of the phosphorus that finds its way here

originates from African fires...

providing an intercontinental lifeline

for the three million species that call this place home.

We used to think the incredible diversity of life here

evolved through the pressures of competition.

But there is also a more subtle and equally powerful force at play.

Collaboration.

Rising above it all is an elegant Brazil nut tree.

She has been growing here for over a century.

At nearly 150 feet tall, she is a pillar of high society.

She has risen to the top by being the ultimate forest networker,

and she has faith that her contacts will provide everything she needs.

Bright yellow flowers brimming with nectar announce that she is ready to reproduce.

But she's a little bit picky.

She only wants to admit VIPs.

Very important pollinators who might have visited another Brazil nut tree.

So her flowers have a protective hood.

It will take someone with a bit more heft to deadlift this doorway.

Astonishingly, this tree is so well-connected

that she can outsource the hard work of finding such an exclusive creature

to a personal assistant.

A neighboring orchid...

looking to lure in a pollinator of its own.

Its captivating aroma is irresistible

to a connoisseur of scents.

This orchid bee is a master perfumier.

Working on his own signature cologne,

he simply must add this divine fragrance to his mix.

He gently gathers the finest aromatic oils with his brushes...

and deftly blends them together in his pouches.

The perfect concoction will make him more desirable to any admirer.

So it must be just right.

Maybe a dab more.

But it's not this perfumed perfectionist who will help the Brazil nut tree.

It's who he attracts.

With the forest air now heady with seductive scents,

bigger, stronger female bees start buzzing about.

And it is these heavyweights who the Brazil nut tree

has been waiting to entertain.

Female bees have the power to prise open the hood...

and deliver the pollen the tree needs to reproduce.

The tree's mastery of the forest network has paid off.

But by next year, her exclusive flowers have turned into a fruit

that is even harder to get into.

Not even a 100-foot drop...

...can spring its seeds from their rock-hard shell.

Only a safecracker could bust into this strongbox.

But this noble tree even has contacts in the forest underworld.

Suspect number one,

the light-fingered agouti.

This toothy rodent is the only creature with the right tools

to jimmy open the case.

And when it comes to the nuts inside, he's just gotta have them all.

If there's any leftovers, he stashes them in little caches throughout the forest.

So he can enjoy them later.

But this forest filcher has so many hidden away,

he can't possibly remember where they all are.

And it's his lost seeds that the Brazil nut has been counting on.

Placing her precious legacy in the hands of such a motley crew might seem reckless.

But that's the wonder of nature's network.

These fantastical collaborations really do work.

And they're so reliable that every single Brazil nut

is created in this extraordinary way.

They are a crop that can only come from a healthy, intact rainforest.

And there's one animal in particular

who is crucial to keeping this whole forest healthy.

A creature who rules his kingdom with an iron fist of fear.

Well, at least he will when he gets out of bed.

A typical teenager.

This young jaguar spends his days sleeping

and occasionally getting up to raid the pantry.

His snacks range from the tops of the trees...

right down to beneath the waterline.

But his boundless appetite means that everywhere he treads,

he breathes not death but life.

Without big cats like him,

this place could look very different.

Fewer hunters would mean a boom of grazers

devouring saplings before they reach maturity.

As older trees die off, fewer young ones replace them.

Sunlight streams in through gaps in the canopy.

The damp understory dries out,

and those that rely on moist conditions...

disappear.

Flowers wilt.

Hummingbirds starve.

Where no large predators roam...

leafcutter ant numbers explode a hundredfold,

ready to strip away the forest one leaf at a time.

Just one missing link,

and the whole network begins to fall apart.

But where jaguars still hunt,

they are the glue that binds together the complex web of the rainforest.

And this voracious teenager,

will even attempt something few other hunters would dare...

taking on another top predator.

A caiman...

waiting to ambush her own prey.

A naive jaguar would be well within her power.

It's all about who gets the jump on whom.

He has landed a meal worthy of even the heartiest teenage appetite.

And one that will have profound knock-on effects.

Because his leftovers are about to start their own journey

that will reveal the mind-blowing secret

of how forests all over the world really work.

The rotting carcass releases a lifetime's worth of nutrients

that seep into the forest floor.

And underground, something is waiting to receive them.

A microscopic thread absorbs the nutrients

and transports them beneath the trees above.

It is just one filament in a vast living network.

The mycelial tissue from colonies of fungi

that spread beneath this entire rainforest.

Their tiny terminals connect to tree roots trading captured nutrients

in return for a share of the tree's own food.

But this is more than just a business transaction.

In some forests, underground networks unite their trees

into a single wood wide web.

A smart system that allows a mutual flow of food and water

from the strongest to the weakest.

Even between species.

A sapling starved of sunlight can be nursed to full strength

by her taller neighbors.

The trees might even use their network to communicate with each other.

A hivemind warning others of disease or attack,

so they can prepare for tough times ahead.

The scale of the planet's fungal networks is staggering.

Laid end to end, they would spread beyond our solar system,

extending more than halfway across our galaxy.

But here on Earth, they work with their trees

to lock away three-quarters

of all our terrestrial carbon safely beneath the soil.

This fig tree is hundreds of years old.

A mother tree.

Many saplings have grown up in her shadow.

But now her life is coming to an end.

The fungal network may allow her one final act of selflessness.

To gift the last of her precious nutrients to her community.

A grandmother's dying wish to provide the best chance for her forest family.

Another tree will grow to take her place and continue her enduring role.

Thanks to the wonders of the wood wide web.

Some scientists today are increasingly seeing forests

as a single interconnected entity...

where plants, animals, and fungi all work together...

as a collaborating, self-supporting community.

The epitome of nature's amazing network.

In the light of these recent discoveries,

it's not too great a leap to see the whole planet

functioning in the same way.

Every life connected.

From a speedy reindeer

to a triumphant hippo.

Every action with its consequence.

From an ocean heartbeat to a fertile rainstorm.

One way or another, all of nature connects to all our lives.

Even if it's not walking down our street.

Life's connections stretch to every corner of the Earth.

But nature's network must be constantly on the move,

dancing to the rhythms of our living planet

and reacting to the passage of time itself.

In a world that is ever-changing,

opportunity is always there for the taking.

But timing is everything.