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MUSIC

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.

INDUSTRY 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 sub

-Antarctic 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. CHICKEN CALL

Collecting food for her hungry chick.

At 10 months old, chicks are the size of a human

toddler and covered in no more than a downy fleece.

CHICKENS CALL 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.

CHICKENS CALL 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.

CHICKENS CALL 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.

CHICKENS CALL 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.

CHICKENS CALL Any one of these huge seals can take as many as 10 penguins a day.

Their best chance is to stay with the crowd.

Their safety in numbers.

CHICKENS CALL Made it.

Only to return in a month's time and once again face death head-on.

It 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 finaly 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's a bit nervous, but 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 seabirds.

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. MUSIC

The wealth of life found around Antarctica's Loney

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.

MUSIC

It's more than 30 metres long. But it's rarely been filmed before.

MUSIC

Only the Southern Ocean can provide the four tonnes of

food... ..that the biggest of all blue whales need every

day.

MUSIC This ocean giant was almost hunted to extinction.

But thanks to an international ban on commercial whaling...

..its numbers are now increasing.

MUSIC

The closer the seas are to mainland Antarctica...

..the colder they become. MUSIC

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.

MUSIC 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. MUSIC

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. MUSIC

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.

MUSIC

But after just eight minutes... ..his mother signals that it's time to head back.

MUSIC 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 fighter jet.

MUSIC

It is the call of a half-ton male weddle seal...

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

MUSIC

She, however, is still producing milk for her pup and so isn't sexually receptive.

But he doesn't stop trying.

MUSIC 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.

MUSIC

She tries to fight off the adult male.

MUSIC

MUSIC

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. MUSIC

As spring arrives, the sea ice retreats, and in a few

places, Antarctica's coast is exposed to the open sea. MUSIC

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.

MUSIC Oh dear.

The chicks, until they're eight weeks old, depend

on their parents for food and, critically, warmth.

Melt water 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.

MUSIC The feathers 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.

DOG BARKS

DOG BARKS

MUSIC

What's lacking in skill... ..is made up for with persistence.

But a parent's labours could be in vain MUSIC

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 melt water 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.

MUSIC

Antarctica is losing the very element that defines it.

Ice.

That is now diminishing six times faster than it once did.

Neumeyer 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 on land.

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, a hundred or so animals strong.

Killer whales are among the most intelligent of all non

-human predators. And they're now working out how to tackle

prey that isn't a Weddell Seal.

And a daily 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 practice 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 coordinated trick of

their part of the 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. Crab eater 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 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.

The With the ice flow having broken in two, the seals have

become more vulnerable. The Matriarch now pushes the ice

flow 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 crab eater 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.

The Leppan seal.

By far the most ferocious of all Antarctica seals.

Dare this pod tackle him?

He's a three-meter adult, an aggressive hunter in his own right.

Unused to being targeted by killer whales, the Leppan seal

makes the mistake of leaving the safety of the ice flow.

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 skillful 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 ice cap, 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 meters 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 meters 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 a hundred 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, a thousand 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

meters tall stand on the desolate valley floor.

The only life form,

a mummified crabby to 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 10 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 lake bed are living structures found nowhere else on Earth.

Giant stromatolites, standing half a meter 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.

Whilst filming in the extremes of Antarctica, capturing the

remarkable behavior of wave-washing killer whales was to

prove the crew's greatest strength. The team set off from

the Falkland Islands on board the Golden Frees, which will

be their home for the next month and a half. It's under the

command of Antarctic explorer Dion Ponce. What's the weather

like for the crossing? First day's 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

Brownlow has yet to find his sea legs. Destroyed. Fourth day at sea. Sick.

On arrival at the peninsula, their search begins, guided

by Lee 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 specialized 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. We found the first killer whales.

These are what we want. Good start.

To get shots low to the water, they launch a gyro-stabilized

camera system in a small boat. There's only half the length

of the killer whales.

Definitely feel like we've just been checked out. It's quite intimidating.

In the filming first, camera operator Bertie Gregory

launches the drone to capture a new perspective on this

hunting technique. We've got four or five killer whales spy

hopping. Some are moving away. They might get ready for a

wave.

That's the first wave. That's the braking wave that's broken the pack in half.

The seal's in the water. The seal's in the water. He could

be in trouble here. 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 groundbreaking

footage is also providing valuable scientific data,

contributing to the long-term study of these highly

specialized killer whales.

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

here she is. This is a photograph taken during Frozen Planet

One. 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. 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 it doesn't

happen so much. And warmer weather here means less sea

ice, which could have consequences for the killer whales'

preferred prey of wet or seals. There's a cruel irony,

really, that we've today found the largest group of wet or

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

crab-eater seals, but then something remarkable happens.

They approach one of Antarctica's most formidable predators, the Lisbon seal.

This is absolutely incredible, because that's really not

considered a key prey for them. Oh, 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. 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 it

to happen.

Thank you for watching!