Original subtitles

David Attenborough: At the far south of our planet

lies the most hostile of the earth's frozen lands.

Antarctica.

Here, temperatures can fall

to below minus 80 degrees celsius...

And winds blow up to 200 miles an hour.

Its icy centre is almost devoid of life.

But on the edge of Antarctica,

some creatures find a way

not just to survive, but to flourish.

Here are some of the greatest concentrations of life

to be found anywhere on earth.

The continent of Antarctica

lies at the southern end of the globe.

Twice the size of Australia,

it's the largest, coldest expanse of land on the planet.

To the north of it, however,

across 1,000 miles of ocean,

lie the subantarctic islands,

where conditions are somewhat less hostile to life.

The largest of them is South Georgia.

Here, a million king penguins live and breed the year round.

A mother has returned after a month at sea...

Collecting food for her hungry chick.

At ten months old, chicks are the size of a human toddler,

and covered in no more than a downy fleece.

Until they get their waterproof feathers,

they themselves cannot go to sea...

So they have to rely totally on their parents

to bring them food.

Their time together is brief -

just long enough to disgorge her crop of fish and squid.

All too soon,

parents have to return to sea to collect more.

But getting back there can take several hours.

Hundreds of parents make the commute together.

A beak can be used as an ice-pick

to negotiate the steeper parts of their trek.

This mile-long snow-covered trudge

is unique to this colony, and has never been seen before.

At last, the sea.

After several days on land,

their feathers need washing to be ready

for the long days of swimming that lie ahead.

But this is a dangerous place to loiter.

Leopard seals.

Three metres long,

more than three times the size of a king penguin,

these fearsome hunters are usually solitary.

But at this time of the year,

in this bay, there are as many as 30 of them.

If these penguins think that they're safe on land...

They are mistaken.

Any one of these huge seals

can take as many as ten penguins a day.

Their best chance...

Is to stay with the crowd.

There's safety in numbers.

Made it.

Only to return in a month's time...

And once again face death head-on.

This is surely one of the greatest challenges

faced by any parent.

1,500 miles off the continent's east coast

lies another of the tiny outposts

that are vital for the survival of antarctic wildlife.

The sub-antarctic islands of the antipodes.

In spring, the longer days turn each tiny speck of land

into a potential breeding ground...

For the antipodean wandering albatross.

Its wings are three metres across,

amongst the biggest of any bird.

This 14-year-old male

is now mature enough to start selecting a partner.

For the smaller, darker female,

choosing a suitable mate is of equal importance.

After all,

they may stay together for the next 50 years.

To make this crucial decision,

they use one of the most elaborate courtship rituals

of any sea bird.

He begins by sky-pointing.

It seems to be working.

Next, he attempts a move...

Known as the double head-Bob.

The finale is the real decider.

Synchronised wing-spreading.

She seems impressed.

But another male appears...

And shows off...

His wings.

The greater the span,

the more attractive he could be.

But the first male won't tolerate

a rival cutting in.

Yet another hopeful joins in the competition.

And another.

This was not supposed to be a dance-off.

She prefers one tango at a time.

It seems that this is not going to be his year after all.

But he's caught the eye of another albatross.

Once again, he begins his courtship display.

But this is, in fact, another male.

Regardless, he continues to demonstrate his eligibility.

This could still be the one

with whom he will share the rest of his life.

On the antipodes islands, it's becoming increasingly common.

Today, there are three times as many males as females.

Females feed further north than the males,

in waters used by industrial fishing fleets

that catch and drown great numbers of sea birds.

As a result, the female albatross here

is now declining fast.

A same-sex partnership like this

may bring no survival advantage...

But is apparently preferable to a life alone.

The wealth of life found around Antarctica's lonely islands

is evidence of the richness of the waters that surround them.

The southern ocean.

It may appear treacherous.

Its Gale-force winds certainly create powerful currents.

But all this stirring has an important effect.

It brings up nutrients from the depths,

helping to create some of the richest seas on earth.

And this provides food for the largest animal

to have ever lived.

The antarctic blue whale.

It's more than 30 metres long...

But it's rarely been filmed before.

Only the southern ocean

can provide the four tonnes of food

that the biggest of all blue whales needs every day.

This ocean giant was almost hunted to extinction,

but thanks to an international ban

on commercial whaling,

its numbers are now increasing.

The closer the seas are to mainland Antarctica...

The colder they become.

Until, a few hundred miles offshore,

the ocean's surface freezes solid.

It forms a cover of sea ice

that is twice the size of Europe

and encircles the entire continent.

This is a stronghold

for one of Antarctica's most remarkable inhabitants.

It uses its teeth

to prevent its breathing holes from freezing over.

The weddell seal.

The most southerly breeding mammal on the planet.

This ten-day—old pup

is still entirely dependent on his mother.

Out on the ice,

it may be safe from marine predators...

But within its first two weeks,

it will have to venture into the underwater world

upon which its future depends.

This is the coldest water on earth.

So it's not surprising

that a pup needs some encouragement.

It's time to leave the safety of the breathing hole.

To catch fish and then safely return,

this pup must learn how to find his way

through the maze of underwater ice caverns.

But after just eight minutes...

His mother signals that it's time to head back.

She can hold her breath for an hour and a half.

But he is already starting to tire

and is running out of air.

On their way back to their breathing hole,

they hear a sound as loud as a fighterjet.

It is the call of a half-tonne male weddell seal

announcing that he's on the lookout for a mate.

She, however, is still producing milk for her pup,

and so isn't sexually receptive.

But he doesn't stop trying.

To repel his advances,

she leaves her pup's side.

But the pup isn't strong enough

to haul himself out without his mother's help.

She tries to fight off the adult male.

She's wounded him so seriously

that he is unlikely to be back any time soon.

A gentle nudge from mother

is all an exhausted pup needs

to make it to the safety of the sea ice.

Mothers stay with their pups for six weeks,

by which time they're strong enough to fend for themselves.

As spring arrives, the sea ice retreats,

and in a few places, Antarctica's coast

is exposed to the open sea.

And that attracts all kinds of animals.

Having spent the winter at sea,

chinstrap penguins can now come ashore to breed.

Soon, the coast becomes extremely crowded.

But there are ways to maintain social distance.

Oh, dear.

The chicks, until they're eight weeks old,

depend on their parents for food

and, critically, warmth.

Meltwater is a particular problem.

The chicks' feathers are not yet waterproof.

Getting wet could be fatal.

A father's duty is to keep his chicks high and dry...

Using the only building material available.

Stones.

And suitable ones are precious.

So it's vital to hold on to every one.

But while backs are turned...

Collections are readily plundered by neighbours.

With thieves like these around...

That stone has just become even more valuable.

What's lacking in skill...

Is made up for with persistence.

But a parent's labours could be in vain.

Summer temperatures have now been recorded

as high as 18 degrees celsius.

As a result, the penguins' carefully constructed platforms

are now being flooded.

There is more meltwater than ever before...

And the ground is becoming a quagmire.

Downy feathers,

which are excellent insulation from the cold when dry,

are no defence when wet.

Hypothermia sets in.

Over the last 50 years,

the number of chinstraps here has dropped by half.

Antarctica is losing

the very element that defines it.

Ice.

That is now diminishing

six times faster than it once did.

Neumayer glacier on South Georgia

has lost nearly six miles of ice in just 20 years.

Parts of Antarctica are warming faster than anywhere else

in the southern hemisphere.

And that is having a serious effect

on the animals that live on its coast,

such as the weddell seal.

With less sea ice available,

many are now hauling out onland.

That's not just a problem for them...

But also for the predators

that specialise in hunting them.

One particular group of antarctic killer whales,

100 or so animals strong.

Killer whales are among the most intelligent

of all nonhuman predators.

And they're now working out how to tackle prey

that isn't a weddell seal.

An adélie penguin, resting on the ice.

A mere snack for an adult killer whale...

But it gives this group of six-year-olds

a chance to practise one of their particularly ingenious

hunting techniques.

Wave washing.

A skill that takes at least 15 years to perfect.

First, the killer whales assess the size and position

of a possible victim.

They must then calculate the speed needed...

For an attack.

But they're too late.

Even though a co-ordinated flick of their tails

creates a reasonable wave...

It's nothing without precision timing.

With fewer of their favourite prey of weddell seals

resting on ice floes,

killer whales now have no choice

but to target new prey.

Crabeater seals.

Numbering 15 million,

they're the most abundant marine mammal on earth.

But they are a far more dangerous target...

Than a weddell seal.

Stronger...

And more inclined to fight back.

But each member of this pod

needs to eat a seal a day.

So the pressure is on to feed.

They're led by a matriarch

who knows exactly what to do.

Living 100 years or more,

she has plenty of hunting experience to draw upon.

With the ice floe having broken in two,

the seals have become more vulnerable.

The matriarch now pushes the ice floe into open water

to give their next wave maximum impact.

This requires teamwork and precision.

She makes her final calculations.

This seal has only one way of escaping death.

Unlike the less muscular weddell seal,

the crabeater has the strength

to hurl itself out of the water...

Just in time.

For the killer whales,

it has been a significant waste of energy.

Their need to eat is now greater than ever.

A leopard seal.

By far the most ferocious of all Antarctica's seals.

Dare this pod tackle him?

He's a three-metre adult,

an aggressive hunter in his own right.

Unused to being targeted by killer whales...

The leopard seal makes the mistake

of leaving the safety of the ice floe.

The killer whales approach the seal with utmost caution.

Keeping away from its powerful teeth,

they seize it by its tail...

And try to drown it.

The hungry youngsters get to feed first.

But tackling less-familiar prey is risky,

and starvation is a real danger for these killer whales.

Only time will tell

whether these skilful hunters can adjust quickly enough

to survive in this changing world.

Beyond Antarctica's rich coastal fringes

lies a vast frozen interior.

This is certainly one of the most inhospitable places

for life on earth.

Its icecap, three miles thick in places,

holds almost two-thirds of the earth's fresh water.

The accumulation of snowfalls over millions of years

has bedded vast mountain ranges longer than the himalayas.

All that can be seen of them is the tips of their peaks.

Smoking vents standing 20 metres tall

hint at the volcanicity that lies beneath the ice sheet.

The recent discovery

of more than 20 previously unknown volcanoes

reveals that Antarctica is

one of the most volcanic places on earth.

Almost 4,000 metres high,

mount erebus is one of just seven volcanoes on earth

with a permanent lava lake.

Less than 1% of this frozen interior

is free of ice.

But isolated outcrops of rock

offer sanctuaries for one of the few animals

willing to brave temperatures of minus 30 degrees celsius.

The snow petrel.

They fly 100 miles inland

in order to breed away from predators.

This male gets to work clearing a shallow scrape,

which he will then line with feathers

to give his chick a little protection

from the bitter cold.

But crevices are

in short supply...

And rivals are ever ready to fight for them.

When aerial combat fails,

snow petrels deploy another weapon.

Vomit.

It could be lethal.

If the putrid stomach oil freezes,

his flight feathers could stick together.

Fortunately, he knows how to clean them...

With a snow bath.

Now to get on with the task of breeding.

From here to the south pole, 1,000 miles further inland...

Conditions become even more hostile for life.

Winds driving over the east antarctic ice sheet

can reach speeds of up to 200 miles an hour.

As these Gale-force winds descend from the ice sheet,

they pick up both speed and warmth.

They create the most arid conditions on earth.

These aren't snowdrifts.

They're sand dunes.

Some of these so-called dry valleys

have not felt rain in over a million years.

Carved by the wind,

strange monuments up to four metres tall

stand on the desolate valley floor.

The only life form...

A mummified crabeater seal

that mysteriously strayed here,

possibly thousands of years ago.

But if you look hard enough...

Life can be found in Antarctica's interior.

Hidden in the mountains of eastern Antarctica,

lake untersee.

A little over ten years ago,

scientists dived beneath its frozen surface...

And made a discovery that would change our perception

of the possibility of alien life.

Lying on its iakebed

are living structures found nowhere else on earth.

Giant stromatolites.

Standing half a metre tall...

Their existence down here

provides an extraordinary insight

into how life on our planet might have evolved.

These living structures have been built

over thousands of years

by arguably the most important microorganism on earth.

Cyanobacteria.

The very first living organisms to have produced oxygen.

Without them, earth would have remained uninhabitable

for higher life forms.

If the building blocks for life can be found here,

in the most hostile place on earth...

Surely life could exist

in the ice-covered lakes of distant planets.

David Attenborough: Whilst filming in the extremes

of Antarctica, capturing the remarkable behaviour

of wave-washing killer whales was to prove

the crew's greatest challenge yet.

The team set off from the Falkland Islands

on board the golden fleece,

which will be their home for the next month and a half.

It's under the command

of antarctic explorer Dion poncet.

Man: What's the weather like for the crossing?

The first day is good.

And then...

Nothing bad... That we can see... yet...

To reach Antarctica, they must first cross the Drake passage -

650 miles of the world's roughest ocean.

Confined to his bunk, executive producer Mark brown/ow

has yet to find his sea legs.

Destroyed.

Fourth day at sea.

Sick.

On arrival at the peninsula,

their search begins, guided by Leigh hickmott,

a whale scientist who is part of a 14-year study

on the only killer whales in the world

known to wave wash.

We now have a greater understanding,

perhaps, of how small the population is,

actually, of these killer whales.

The parent population is about 50 animals.

So really not very many at all.

With so few of these highly specialised killer whales

patrolling an area more than half the size of wales,

they head to where they were last sighted.

After three days of round-the-clock surveillance,

the team finally catch a glimpse.

Found our first killer whales.

Man: There's the one we want! Woo!

Good start.

To get shots low to the water,

they launch a gyro-stabilised camera system in a small boat

that's only half the length of the killer whales.

Man: Stay still.

That's so cool!

Definitely feel like we've just been checked out.

It's quite intimidating.

In a filming first, camera operator bertie Gregory

launches the drone to capture a new perspective

on this hunting technique.

We've got four, five killer whales, spy hopping.

Some are moving away! They might get ready for a wave.

There's the first wave!

That's the breaking wave that's broken the pack in half.

Gregory: The seal's in the water!

Seal's in the water! He could be in trouble here.

Brownlow: They could just kill the seal cleanly,

but they are using the seal to teach their young how to hunt.

It's really hard to watch.

The team's ground-breaking footage

is also providing valuable scientific data,

contributing to the long-term study

of these highly specialised killer whales.

Animal b-17, she was first photographed back in 2009.

So here she is.

This is a photograph taken during frozen planet I.

If we look on the right,

here's a picture that we took during our cruise.

She's certainly the matriarch of her particular group.

We're seeing how she's teaching her offspring

to become this very efficient killer.

But after such a promising start,

conditions take a turn for the worse.

Poncet: The thing that's changed

enormously here is the weather.

In the past, the peninsula was famous for

perfect calm, still,

bright sunshine, clear skies.

And...

Doesn't happen so much.

And warmer weather here means less sea ice, which could

have consequences for the killer whales'

preferred prey of weddell seals.

Hickmott: There's a cruel irony, really, that we've

today found the largest group of weddell seals,

but they're on the beach.

They're not on pack ice. And that's potentially

because the antarctic peninsula is one of

the most rapidly warming places on the planet.

The team film the killer whales

switching to hunt crabeater seals...

But then, something remarkable happens.

They approach one of Antarctica 's

most formidable predators, the leopard seal.

Hickmott: This is absolutely incredible,

because that's really not considered a key prey for them.

Ooh, he's chosen a bad piece.

The ice has split into four...

And he's chosen the smallest quarter.

It's phenomenal.

It's the first time a killer whale

hunting a leopard seal has been captured on camera.

As extraordinary as that is,

it's a sobering indication of the challenges ahead

for these killer whales.

Hickmott: I don't think it's too much to say

that we are facing a climate emergency.

There's a real chance that,

as we lose this pack-ice environment,

that this predator, that has one of the most complex

foraging strategies on the planet,

is going to be potentially lost.

And that's a tragedy that I,

in my lifetime, don't want to see.

And for our children, most certainly,

we can't allow to happen.