All language subtitles for Planet.Earth.III.S01E04.Freshwater.2160p.UHD.Blu-ray.Remux.HDR.HEVC.TrueHD.7.1.Atmos-CiNEPHiLES_ENG_Subtitles02

Beneath the Yucatan Peninsula

of Mexico...

...lies another world.

A labyrinth of caves...

...carved by freshwater.

An essential for life on Earth.

Freshwater shapes the land

and the creatures that live in it...

...in the most surprising ways.

The rainforest of Costa Rica.

As you might expect,
it rains most days.

But it's only during the wet season

that the rains become torrential.

And with them...

...comes
a most remarkable creature.

Gliding tree frogs.

Thousands drop in...

...together,
at this newly formed pond.

They all have an urgent need.

To breed.

This female needs to find a leaf

and lay her eggs.

The breeding frenzy
will only last one day...

...so she needs
to get a move on.

There are lots of eager males.

Nine for every female.

And all are ready
to spring into action.

So for her, getting a partner
is no problem.

But the other males are desperate.

For this female,
mating is rather chaotic.

Things are getting out of hand.

There is one way to deal with this.

A few well-placed kicks...

...usually does the job.

Problem solved.

She and her partner
can now finally mate...

...in relative peace.

The eggs are positioned perfectly...

...directly overhanging
the pond.

This is the ideal nursery
for tadpoles.

For now, her work here is done.

She'll be back next year
when the heavy rains return.

As quickly as freshwater appears...

...it can vanish.

Southeast Sri Lanka.

It's the middle of the dry season.

This is the only remaining water hole

for miles around.

Mugger crocodiles.

Giants. Five metres long.

Dozens are hiding

beneath the surface.

And others...

...are on their way.

This male has been travelling
for hours.

The water hole is the only place

where he has a chance to catch a deer.

A single adult would be enough
to feed him

for the entire dry season.

But hunting prey
that knows you're here...

...requires something
truly remarkable.

He creates...

...a trap.

He digs down into the mud.

Deep enough to hide
beneath the vegetation.

Perfect camouflage.

He has built his trap
right on the water's edge.

So it's the first place

that thirsty deer will come to drink.

These crocodiles
have learned to exploit

the deer's desperate
need for freshwater.

Freshwater transforms

not only the lives of animals...

...but entire landscapes.

Every year,
over a trillion litres of water

flow into the Kalahari Desert.

It has travelled a thousand miles

from where it fell as rain.

And on arrival...

...it turns the Kalahari

into a vast oasis.

The Okavango Delta.

These waters attract
millions of animals.

And for some,

now is the perfect time
to raise a family.

A lily-trotter.

And he is a father...

...on duty.

He has not just one...

...but four
newly hatched chicks.

They won't be able to fly
for another six weeks.

So, until then,
he alone is their protector.

Walking on water
is not straightforward.

So he must show them
how to be a lily-trotter.

The floodwaters make
the perfect training ground.

And in two weeks...

...his chicks not only double
in size...

...they grow in confidence.

But this is a dangerous place
to stray.

He sounds the alarm,

and his chicks instantly freeze.

They can't yet fly to safety.

But there is one thing he can
do to protect them.

And it's risky.

Get close enough to distract...

...and hopefully divert
the crocodile.

Mission accomplished.

He signals the all-clear.

But one chick is missing.

His calls go unanswered.

A little bedraggled,
but alive and well.

His chick just hadn't heard his call.

And when danger threatens,

it's always better to be safe
than sorry.

He's brought his chicks,
all four of them,

to the verge of independence.

Whilst lily-trotters
are well adapted to life

in this flooded world...

...these residents of the delta
are not.

African painted dogs.

Normally, they are
remarkably successful hunters,

but this pack of five
hasn't eaten in days.

Finding prey isn't the problem.

This herd of lechwe is only
a few hundred metres away.

But between them is deep water.

It's not safe to cross here.

On dry land, the dogs can run
at over 40 miles an hour.

But when threatened,

lechwe always seek
the safety of water.

With their splayed hooves
and long hind legs,

they can power their way
through the water.

The dogs can't.

The pack won't be able
to outswim the lechwe.

But they do have a strategy.

The dogs drive the lechwe to where

they have the advantage.

Back towards dry land.

Now the pack can regain lost ground.

Success today,

but tomorrow the pack
will need to hunt again.

In the Okavango,

animals must always adapt
to the coming and going

of freshwater.

But there are a few rare places,

as here in Lake Malawi,

where freshwater has lain
for millions of years.

And that has enabled life to evolve

into a dazzling diversity of species.

There are over a thousand
different kinds of fish here.

More than any other lake on Earth.

Competition in these waters
is intense.

Meet Nimbochromis livingstonii.

A master of deception

that tricks other fish
into thinking it's dead.

Its mottled colouration
mimics decaying flesh.

But to appear dead...

...one must at least act dead.

This juvenile is fooling no-one.

Perhaps faking his death
will be more believable.

Blown it.

A more subtle performance
will be needed.

This is more convincing.

But his aim must be better than that.

Nearly.

It seems he's overstayed his welcome.

In a final effort,

he appears to even hold his breath.

Success at last.

All it took was a million years
of evolution...

...and the unique stability
of this ancient lake.

Off the western coast
of equatorial Africa

lies the volcanic island of Bioko.

Freshwater here
has a turbulent nature.

Few venture into such waters,

but for those that do,

there can be great rewards.

After months feeding
and growing out at sea,

these gobies are ready to breed.

And the safest place to lay their eggs

is somewhere that
ocean predators can't reach.

The top of this waterfall.

Surely an impossible journey
for a fish.

But over the coming days,

the gobies transform themselves.

They change colour.

Their mouth rotates and acts
like a kind of suction cup.

Which they will certainly need.

Because the only way...

...is up.

It is 30 metres to the top.

They are only an inch long.

This is the equivalent

of a human being scaling a waterfall

over a mile high.

Millions attempt the climb...

...but less than 1%
will make it.

This goby has been climbing for days.

Made it!

Those that reach the top
can now prepare to breed.

And when the time comes,

their young will be washed
back out to sea.

The extraordinary power
of flowing water

makes it our planet's
greatest architect.

This may look like the surface
of an alien planet.

But these strange patterns
are channels of freshwater...

...flowing towards the sea.

For 3.8 billion years,

ever since the first rains fell...

...freshwater has been making
this journey.

But today, two thirds
of our world's great rivers

no longer reach the sea.

There is a finite amount
of freshwater on Earth.

So humans have devised
extraordinary means

to ensure that it is always available

to meet our every demand.

We now control freshwater

on a colossal scale.

The largest irrigation system on Earth

has been built here, in Pakistan.

A vast network of dams and canals...

...that diverts and drains
the great Indus River.

It's used to irrigate an area
the size of England.

This man-made freshwater world

provides water and a livelihood

for millions of people.

But at a cost to the natural world.

A rare creature has become stranded

in this irrigation canal.

And the water will soon be gone,

used to supply the surrounding land.

Endangered, they number fewer
than 2,000 individuals.

An Indus river dolphin.

This female dolphin is 150 miles

from the main river.

She can't return on her own.

So the only option

is for this rescue team to take her.

Out of water,
she cannot survive for long.

The journey back to the river
will take hours.

Her life now depends on these people.

Nearly 30 dolphins had to be rescued

in one month alone.

Freshwater is not only
a resource for humans...

...it is the home
for countless species

that simply cannot survive without it.

Freshwater is the lifeblood...

...of Planet Earth.