All language subtitles for Planet.Earth.III.Ep06.Extremes.2023.1080p.BluRay.x264.Atmos.TrueHD7.1-WiKi.English

DAVID ATTENBOROUGH:
This is the entrance

to one of the greatest
of natural wonders.

Hang Sơn Đoòng in Vietnam.

It's thought to be
the largest cave on Earth.

Here,
200 metres underground,

for just a few weeks a year,

sunbeams cast light

through a hole
in the cave's roof.

There is just enough light

to enable plants to grow.

But travel deeper

and darkness returns.

And you reach the limit

of where life can exist.

These most extreme places
on our planet

are often hard for us to reach.

Indeed, this cave
was only recently discovered.

And it contains many surprises.

Cave pearls.

Once tiny sand grains,

now spheres
the size of tennis balls.

And giant stalagmites...

...formed over centuries

by billions
of individual drops of water.

Underground rivers

have carved this great passage
through the limestone.

Over five miles long

and wide enough in places

to accommodate a jumbo jet.

And it is here,

in the cave's furthest chamber,

that life can be found.

Translucent cave fish...

...and shrimps.

Isolated for millennia,

feeding on little more

than the nutrients
from the jungle above.

The fish are completely blind

and find their way about
by touch alone.

These underground worlds

are at the very limit
of where life can exist.

But above ground,

our planet's
most extreme conditions

are found at the poles.

(WIND WHISTLES)

Here in the north,

winter temperatures can drop

to -50 degrees Celsius.

For four months of the year,

there is barely
a glimmer of sunlight.

But here, too,

life finds a way to survive.

A pack of Arctic wolves.

Their dense fur
has protected them

through months of bitter cold.

But now the sun is returning.

This is Ellesmere Island.

The short summer

gives the wolves a chance

to rebuild their strength.

But here in the Arctic...

...life is never easy.

This pack is led

by an experienced female.

If she can't lead them to food,

the coming winter
could be their last.

Prey is spread over
such a vast area

that they must be
constantly on the move...

...in search of it.

But finding prey

is only the beginning.

Musk oxen.

They are five times
the size of a wolf.

(SNORTING)

The conflict
between wolf and oxen

is an ancient one,

and has been waged
since the Ice Age.

(SNORTING AND GRUNTING)

Each side knows
the other's tactics.

(SNARLING)

The wolves try to isolate

the weak or the young.

A calf stumbles...

...and the pack leader

immediately closes in.

(GROWLING)

But the herd regroups,

horns at the ready.

Stalemate.

But it can only be brief.

This time,
the herd race to higher ground.

As they reach
the top of the ridge,

the males turn

to defend themselves.

(GROWLING)

Stalemate...

...again.

Every unsuccessful hunt

leaves the pack weakened.

This could be an easier meal.

(SNIFFING)

But something is not right.

This musk ox
has died from a disease.

(SNIFFING)

Outbreaks like this

are becoming
increasingly common

as the climate warms
across the Arctic.

Despite their hunger,

the pack
don't eat this carcass.

Another herd.

Another chance for the pack.

This time,

the wolves
manage to split the herd.

That may improve their chances.

The lead female
makes sure that the oxen

do not reach the ridge again.

With one less defender,

the calf is more vulnerable.

A much-needed meal.

The wolves
must continue to make the most

of the remaining weeks
of summer...

...so when winter returns...

...they're ready to endure

some of the harshest conditions

that exist on Planet Earth.

Such inhospitable extremes

are not only found
at the poles.

As altitude increases...

...temperatures fall.

Here, too,

animals must make the most
of the seasonal change.

Particularly
if you're ready to mate.

A male common frog

in the French Alps.

He has spent all winter

hibernating under the ice.

But now it's time to wake up.

Being cold-blooded,

he needs the sun
to warm his body.

But once it sets
in a few hours' time,

he could freeze to death.

So finding a mate is urgent.

The weather is good.

And he starts to sledge.

But this is not
a one-frog race.

Dozens are rushing
to the breeding pool.

This many frogs
out on the slopes...

...doesn't go unnoticed.

You can't afford any slips.

It was all going so well.

Made it.

(CROAKING)

But all the females
have already got partners.

There's only one thing for it.

Wrestling.

Not this time.

Another latecomer.

A female.

Could she be the one?

Sometimes being late

can pay off.

After all his efforts,

the male
is not going to let this chance

slip through his fingers.

This is the cedar forest

of the Atlas Mountains
in North Africa.

These Barbary macaques

enjoyed a summer of plenty,

but now
they're paying the price.

Winter here can be brutal.

In some years,
over half the group perish.

But in this macaque society,

the more social the monkey,

the more likely it is
to survive.

Keeping warm by huddling

can make all the difference.

But they can't huddle all day.

They must, eventually,
break apart to feed.

They spread out,
searching for food.

But each night,

the group return
to huddle in the cedar trees.

No-one wants to be left out.

Especially the infants.

This baby, somehow,
has got separated.

He must get back

to the life-saving warmth
of the huddle.

And soon.

But there is an obstacle.

A grumpy male

is giving the baby
a rather cold shoulder.

(GRUNTING)

(CHITTERING)

Maybe a more subtle approach.

The male decides to leave.

At last...

...an enthusiastic reception.

The male has had less luck.

It could be a long night.

Huddling might seem a simple
expression of affection,

but among these macaques
it's essential for survival.

And not just here.

5,000 miles away
in the forests of Mexico,

monarch butterflies,
in millions,

also huddle for survival.

All of them have travelled
across North America

to escape the winter
that is coming there.

This forest,

at an altitude of 3,000 metres,

might seem to offer
little comfort...

...for temperatures here

can drop below freezing...

...and that could
kill the butterflies.

But in fact,
a thin layer of warm air

trapped by the tree canopy
protects them,

and will do so
throughout the winter...

...provided that the forest
remains undisturbed.

Unpredictable extremes
of weather, however,

can disrupt
this delicate balance.

Strong winds
can push deep into the forest,

chilling the air.

(WIND GUSTS)

Hundreds of thousands
of butterflies

may be blown from the branches.

In some years, storms kill 75%

of hibernating monarchs.

This one has survived...

...but on the ground.

And night-time frosts
are fatal.

It can't stay here and live.

It is too cold to fly,

but it must get back
into the tree branches somehow.

So it starts to climb.

It's the equivalent of a human

climbing up a skyscraper.

Safety at last.

As spring returns,

the monarchs wake
from their long slumber.

And now starts

one of the Earth's
greatest natural spectacles.

But this mass awakening
is under threat.

The changing climate

is creating
more extreme weather,

and storms
are becoming more frequent.

But, for now,

this miracle of nature
continues.

Fire.

Unpredictable and destructive.

This is South Africa's fynbos.

Botanically one of the most
diverse habitats on Earth...

...with over 8,000
different plant species.

Yet, every two decades,

fire reduces the vegetation
to ashes.

This may seem catastrophic.

But just days later,
plants burst into life...

...and transform the landscape.

Seeds and bulbs

have been waiting
for this event.

90 million years of evolution
alongside fire

has made some plants
so closely adapted

that they can't germinate
without the presence of smoke.

Remarkably, around 50%

of Planet Earth's
terrestrial habitats

depend on fire
to remain healthy.

In Northern Australia,
these savannahs

need seasonal fires
to keep them open

and prevent the spread
of the nearby forest.

And they are a vital habitat

for this colourful resident.

The rare
golden-shouldered parrot.

He and his lifelong partner...

...rely on grassland
for both food...

...and a nest site.

As usual,
they've laid their eggs

in a hole in a termite mound.

(CHEEPING)

And now there are four chicks.

The thick mud walls

don't only protect chicks
from predators,

but insulate them

from the heat
of the scorching sun.

With fledging just days away,

the parents
are working overtime.

They collect thousands of seeds
every day.

But they have a problem.

The fire season
is becoming more irregular.

If they are not ready to fly,

chicks have no escape.

But choosing to nest
in a termite mound

has a surprise benefit.

Their home is fireproof.

Concrete-like walls

keep chicks safe
from the flames outside.

The seeds of fire grass

are now easier
for the parrots to find

on the blackened earth.

And they are the parrots'
favourite food.

So for both adults
and their fledgling chicks...

...fires are essential
for survival.

But their grassland home
is shrinking,

and only about 1,000
of these lovely parrots

still survive.

It's through
the active management of fire

by humans that their world
now exists at all.

Humans are affecting habitats
across Planet Earth.

For wildlife, all too often,

the consequences
have been disastrous.

Elephants are among
the most tolerant of animals.

(GRUNTING)

They are very long-lived,

and knowledge
passed between generations

enables them to find food

and little-used
sources of water

in times
of great environmental stress.

But even among elephants,

survival strategies
are now beginning to fail.

In Amboseli, Kenya,
years of extreme weather,

combined with overgrazing
by domestic cattle,

are turning these grasslands
to dust.

This matriarch
is over 40 years old...

...and she's already survived

some of East Africa's
worst droughts.

But this year, food is in
extremely short supply...

...and her family
are struggling to find enough.

Her youngest son
is malnourished and weak...

...and is lagging behind
his mother and brother.

She leads them

to a pocket of acacia forest
that she knows well.

But broken branches
and fallen trees

show that other elephants
have already been here.

There is very little left
worth eating.

Without food,

his mother cannot produce
enough milk.

She has no choice...

...but to leave
her weakening calf...

...and try to find food
elsewhere.

So she...

...and her elder son
head off...

...without him.

He can only hope
for their return.

(FLIES BUZZ)

But for him,
time has run out.

There is nothing his mother,
or anybody,

could have done to save him.

(LOW RUMBLING)

With her elder son still alive,

there is hope for her family.

But only
if they can adapt quickly.

Some families
are proving to be resilient.

They're travelling
long distances

away from Amboseli...

...and finding new sources
of food and water.

And despite the drought...

...calves are being born.

But given the pace of change

and the challenges they face...

...how many
of Africa's elephants

will be able to adapt...

...and can they do so
fast enough?

The Gobi Desert.

A land of sand and snow.

For at least a million years,
this has been

one of the most extreme
habitats on Earth.

Yet footprints in the sand

reveal that there is life here.

A snow leopard.

Seldom seen...

...especially in such hot,
arid conditions.

They live up to 2,000 metres
above sea level,

and patrol vast territories.

They are rarely seen together.

A mother...

...with cubs.

Filmed here for the first time

in such intimate detail.

And they give us a glimpse
of their family life...

...such as it is.

Snow leopard cubs
stay with their mothers

longer than those
of almost any other big cat.

They remain together
for over two years...

...as they learn how to master
the extremes.

Which they do so well
that they are able to thrive

in some of the hottest,
coldest...

...and highest places on Earth.

Some animals,
over millions of years,

have evolved ways of surviving
extremely hostile conditions.

But as the extremes
become more extreme...

...evolution is being outpaced.

These extraordinary places
are still inhabited

by some of Earth's
most resilient

and adaptable species.

But in our
rapidly changing world...

...this is Planet Earth

as you may never see it again.

(YOWLING)

DAVID ATTENBOROUGH:
The most extreme parts

of our planet
are not always found

where you might expect.

Hidden deep in the forests
of Vietnam,

a local man, Mr. Ho Khanh,

made an extraordinary
discovery.

He didn't know it at the time,

but he had stumbled upon

arguably the largest cave
in the world.

Inspired by Mr. Ho Khanh's
discovery,

the Planet Earth team
set out to film Hang Sơn Đoòng.

But first,
they have to get there.

We've left the river valley.

We're walking uphill now
to the entrance.

It's just thick, thick forest.

After trekking
for two gruelling days,

the team finally arrive.

Down here is the entrance
to Hang Sơn Đoòng,

this tiny opening
in this massive jungle.

It's amazing that anyone
ever found this place.

We're about to go in
for the next 18 days,

and it's lights on
from here on out.

Local experts guide the team

through the darkness.

- OK, I can go?
- Yes, please.

(PANTS)

(CHUCKLES)

I'm good. I'm OK.

It's just really slippery.

A complex system of ropes

leads them down
a 90-metre descent.

(RADIO CHATTER)

OK. Thanks.

After four hours
clambering over rocks...

...they finally reach
what will be their camp.

The team wake to a new day.

But in darkness.

GEORGINA: How did you sleep,
Luke?

Quite tired.

These are all of the tents
behind me.

You can see...
they are pretty...

...pretty snug.

This is where
we have our breakfast

every day.

Made by some amazing cooks.

This is our charging station.

Batteries for camera equipment,
batteries for our lights,

our head torches,
which are so important.

This is our water station.

Everything that we have got
has been brought in by someone,

so you can't shower or wash.

And it's not just water.

Tonnes of equipment

has had to be carried
into the cave,

every inch of the way.

Now, deep underground,

the powerful lights reveal

just how vast this cavern is.

That is amazing.

- Look at that.
- It's huge!

As you turn on
each of the lights,

another part of this
enormous chamber is revealed.

It's magic. Absolutely magic.

To try and capture
the true scale, the team

attempt a filming technique
never tried before.

We're trying to

do a little bit of a dance
with the drones,

whereby we have one drone

sort of
slightly below the other,

one filming the other one

lighting a feature in the cave.

It's a really tight space,

you can't see anything.

What could go wrong?

OK, slow down a bit.

It's making everyone
a little nervous.

Yeah, don't go up any higher,
Luke.

OK, that's a nice height.

With one drone lighting
and one drone filming...

...they reveal the wonder

of some of the world's largest
stalagmites.

As the days pass,

the team settle into
the everyday routine

of life underground.

This is the epitome
of being off-grid.

We call that one seesaw loo

because it's kind of on a rock

and every time you sit on it
and lean back, you're scared

that there's going to be
a disaster.

The strangest thing
is having no connection

to the outside world
whatsoever.

Time is warped.

Nothing makes sense
underground.

Without daylight to guide them,

the team worked round the clock

to capture the cave's
most unique features.

Most special of all,

an event which happens
only a few weeks a year.

To get there,
they must navigate

through boulder fields
and tight squeezes.

(BLEEP)

Here, around half a million
years ago,

the cave roof collapsed,

opening a window
to the outside world.

The team wait
for just the right conditions.

We've been sat here for hours.

And finally, just on the
right-hand side of the wall,

we can see
the first signs of light.

After weeks of darkness

200 metres underground...

...they see sunlight

illuminate the cave floor.

The way it just lights up
this massive cave.

When we've been trying to do it
with about four or five lights

and barely even lighting
the smallest section,

when the sun comes in,
it just... (PUFFS)

I think everyone's
got goose bumps.

LUKE: I don't think

I've ever appreciated sun
so much in my life.

It's incredible.

Look at the backlit waterfalls.

They're so slow coming down.

It's literally one of
the best things I've ever seen.

For the crew,

the sunbeam
marks a profound end

to their time in the cave.

We're outside!

It's so green. It's so bright.

Being back above ground
feels like where we belong.

It's a wonder to imagine
what other extremes

still lie beneath the surface
of Planet Earth.