Original subtitles

The Sun is absent for up to half the year in the Polar

Regions. When it returns at the beginning of spring, its

warmth will transform this magical ice world.

The greatest seasonal change on our planet is now underway.

Antarctica is still locked in ice and surrounded by a

frozen ocean. Nonetheless, there are signs of spring.

The daily penguins are arriving, just the males. They've

spent five months at sea where it's warmer than it is on

land, and now they're in a hurry, for spring will be short.

They have travelled 6,000 miles across the ocean since

leaving their colony last year, and now they're returning to

breed. They cannot lay their eggs on ice, for they would

freeze, so they have to come here, where there is bare rock.

Over the coming months, the few parts of Antarctica that

are ice-free will be the stage on which five million Adelies

will build their nests.

To construct one, they need pebbles, and without a good

-looking nest, a male will be unable to attract a female

when they, at last, arrive. An impressive property demonstrates your worth as a mate.

It takes stones of all shapes and sizes to build a decent

nest, and finding ones that are just right is not easy.

So some penguins turn to a life of crime.

The one who has been robbed seems unaware that the

thief is just over his shoulder, and looking for more.

The thief's nest is coming along nicely, probably because he

keeps a particularly sharp lookout for robbers. After all,

he takes one to know one.

It's still cold, but the early-season sun does lift the

temperature by a few degrees. That, however, can have

unexpected, even dangerous, consequences.

The sea is heating faster than the land, pulling cold

air from the middle of the continent towards the coast.

These catabatic winds are stronger than any hurricane.

They are the coldest and the most ferocious on the planet.

The storms catch many new arrivals by surprise, and are the

reason that spring here is, in fact, the deadliest season.

Here, early birds take a great risk.

Some years, entire colonies are lost, buried beneath the

snow. The survivors of this storm must hope that the females

prove to be worth the wait when they finally decide to turn up.

Spring in the north of our planet. The sun, after an absence

of six months, breaks the horizon for the first time.

A female polar bear emerges from her den beneath the snow.

The sun must be a welcome relief after so long in the

darkness.

Her den is on a high slope, well away from hungry male bears

who would kill her cubs, but close enough to the sea ice

where she can find food for her extraordinary new family.

Three young cubs.

If you can raise them all to independence, it'll be a rare achievement.

One of the cubs is underweight and will be fortunate to survive these early weeks.

If the family reaches the sea ice where the female can catch

seals, her milk will be enriched and the smaller cub will

quickly gain size and strength. The sea ice, though, is a dangerous place.

The male polar bear has been out on the frozen ocean all

winter. Times have been lean and a bear cub would certainly

make a welcome snack. However, the mainstay of his diet

is seals and now is the time when they have their pups.

The surface of the frozen sea is marked with pressure ridges

and cracks created by the fluctuating tides. Both are good

places to look for seals.

He has detected a seal den beneath the ice. Now he must

pinpoint it using only his extraordinary sense of smell.

By treading lightly, he can avoid scaring his prey.

He will need to punch through a meter of snow to reach the

den. And if his aim is not exactly on target, the seal will

certainly escape.

In fact, the ringed seal abandoned her den just a few hours

ago and her pup has climbed up onto the surface. It's more

exposed up here, but it's easier to see an approaching bear.

The pup is well camouflaged, difficult to see

when its mother has left it to go fishing.

But he can still smell it. He can

smell it. Nine out of ten polar bear hunts end in failure.

The sun's warming effect on the Arctic is increasing

and the sea ice is showing the first signs of weakening.

Inland, the northern rivers are still locked in ice. The

frozen waterfalls are like dams, holding back billions of

tons of fresh water that has not moved for almost six months.

The vast watershed lies motionless, but as spring advances, it begins to stir.

The frozen waterfalls start to weaken. Above them, the pressure is mounting.

Now from high above, whole sections can be seen to be on the move.

The waterfalls are straining to hold back the force that is building up above them.

The dam bursts and the river is unleashed.

Millions of tons of ice fall. The ice grinds their

way downstream, driven by the unstoppable force of the

meltwater.

Boulders and trees are plucked from the bankside.

Within just a few days, the rivers of the north are

all running. The Arctic's fresh water is flowing again.

These vast floods contain 10% of the world's fresh water,

and as they enter the ocean, they accelerate the break-up.

Soon, an area of sea ice the size of

Australia will vanish from the Arctic Ocean.

As the huge ice sheet breaks up, wildlife returns to the north.

The polar bear mother has made it to the edge of the sea

ice, but the smallest cub is nowhere to be seen. It's a sad

outcome, but the disappearance improves the chances

of the remaining two, who now have more milk to share.

Having led her cubs to the edge of the ice,

the mother's next challenge is to catch a seal.

Not easy with these two in tow.

Her prey beneath the ice can detect the slightest vibration,

especially from bears, and this is not the stealthiest of

hunting parties.

Leaving her cubs behind, however, is not an

option. A male bear would eat one in a moment.

This is not going to be easy.

It seems that the cubs already see themselves as fearsome

hunters, but they're still young enough to accept their

mother's discipline. It's the naughty corner for you.

This is not going to be their lucky morning. They saw no

sign of a seal and the cubs are hungry again. The mother has

been nursing for four months without once eating herself,

and now her milk is drying up. She must catch a seal soon,

or the whole family will starve.

The challenge of finding food is getting harder. She needs

the sea ice as a platform from which to hunt, and it's

breaking up faster with each passing day.

Even the ice around the coast is starting to break.

The first cracks here are eagerly awaited by some.

Narwhals.

The unicorns of the north are on a mission to reach the new

fishing grounds in the bays that have been frozen up all

winter, but are now opening up.

To get to them, the narwhals must travel down leads,

temporary cracks in the ice. But these new roads could close

at any time, cutting off the air that they need to breathe.

The road narrows until there's barely room for one-way

traffic. Then a surprise. Narwhals coming from the other

direction.

It's a standoff. Each team faces an armory of sharp tusks.

Finally, one side concedes, and everyone continues in the same direction.

Within a week, the remaining bays break wide open, and

the narwhals turn their attention to social matters.

No one knows exactly what the narwhal's tusk is for. Some

say it's used for fencing, yet these exchanges are too

gentle to be real fights.

Perhaps these encounters are to remind each

animal of where it stands in narwhal society.

We may never know.

Bizarre creatures appear as if from nowhere. The tiny

plankton they eat have been fueled by the increasing warmth

of the sun, and fertilized by the nutrients brought down by

the great rivers and released from the melting sea ice. Sea

gooseberries strain the water with their stinging filaments.

Their beating cilia scatter the sun's rays into dazzling

bursts of color.

Beneath the breaking sea ice, a predatory sea slug flies

through the water on translucent wings. It's on the trail of

a peculiar swimming snail.

And now, the most voracious of the plankton eaters swim up from the depths. Arctic cod.

The shells can be enormous, some containing 500 million

fish, and predators travel hundreds of miles to feast on

them.

The cod harvest is the annual event for the birds and seals of the far north.

For just a short period, the combination of the

strengthening sun, the newly flowing rivers, and the

breaking sea ice make the Arctic Ocean teem with life.

The land is also transformed by the sun's heat.

The small patches of bare ground that appear are darker

than the snow, so they absorb more of the sun's energy. This

accelerates the melt.

The Arctic tundra is unveiled.

By tracking the sun, Arctic poppies catch its rays around

the clock, so their flowers are always warmer than their

surroundings.

For early season insects, this warmth is even more valuable

than nectar if they are to stay active in the cold.

The woolly bear caterpillar does not need the warmth from

flowers to kickstart its spring. It's always the first

insect to appear after the snow retreats, and

the story of how it does so is truly astonishing.

At the start of spring, the caterpillar eats as fast as it

can, as indeed it must, for this far north the season would

be brief. The days shorten only too soon, but the

caterpillar has not yet got enough reserves to transform

itself into a moth. It can't leave the Arctic, for it can't

fly, so it settles down beneath a rock. The sun's warmth

rapidly dwindles.

Beneath the rock, the caterpillar is out of the wind, but

the cold penetrates deep into the ground. Soon its heart

stops beating. It ceases to breathe, and its body

starts to freeze. First its gut, then its blood.

Spring.

After four months of darkness, the Arctic begins

to thaw, and the caterpillar rises from the dead.

By the time the first shoots of willow appear in the early

spring, the woolly bear is already eating. But no matter how

fast the woolly bear eats, it will not have time to gather

enough food this year either, and the cold closes in once

again.

Year after year, the caterpillar slows down in the autumn, and then freezes solid.

But eventually, a very special spring arrives.

This one will be its last.

It's now 14 years old, the world's oldest caterpillar. Its

remaining days now become frantic. It starts to weave a silk

cocoon.

Inside, its body is changing into one that can fly and

search, abilities that will be crucial in the days ahead.

It's waited over a decade for this spring, and now its time is near.

All across the Arctic, moths are emerging. After completing

their 14-year preparation, they now have just a few days to

find a partner and mate.

No life illustrates more vividly the shortness of the Arctic

spring, or the struggle to survive in this most seasonal of

places.

As spring advances, the transformation of the tundra continues.

Migrants begin arriving from the south, and

suddenly the tundra is alive with birds and chicks.

The Arctic's transformation is complete.

This influx of life is good news for some permanent residents.

Food is rarely plentiful out on the tundra. The Arctic

wolves must make the most of this boom while it lasts.

The wolves must gather as much food as they can. Many miles

from here, other members of the pack are relying on them.

This barren landscape is a hard place to make a living,

forcing wolf packs to be smaller here than further south.

Six hungry moths to feed. The cubs are just over a month old.

The ducks are devoured instantly, but on the long journey

home they also caught an Arctic hare, a mainstay of the

tundra diet, and one the cubs seem to be particularly keen on.

Uneaten food is usually hidden for leaner times, but there

will be no leftovers today. The cubs are growing fast and

are always hungry.

The good times are certainly back, but these white wolves

remind us of the Arctic's less welcoming side. Their coats

are pale to conceal them during the long, snowy winter.

It's easy to forget that one month ago, this land was a barren white desert.

At the southern end of our planet, the Antarctic sea ice is

still at its greatest extent. But there are a few islands on

its outer edge that the sea ice never quite reaches.

South Georgia is washed by the rich waters of the southern

Atlantic, and the comparative warmth of the sea takes the

edge off the vicious southern winter.

It's even possible for a few hardy animals like the

wandering albatross to live here throughout the whole year.

The enormous albatross chicks take 13 months to fledge, so

they have no choice but to sit here throughout the winter.

It can't be easy, but the thick layer of fluffy down keeps

out the worst of the cold. Their parents travel thousands of

miles to collect the fish and squid they need to stay warm and to grow.

The season is turning, and storms blow in with little warning.

King penguins have also been here all winter.

Their chicks survive by huddling in crashes to conserve

their heat. A solitary bird here standing alone would

quickly die of exposure. It seems for a hardy few, violent

storms are a price worth paying for year-round fishing in

the rich waters of the southern ocean.

The penguins have had the beach to themselves all

winter, but that is a luxury that will not last.

As the winter storms subside, life begins to return.

For half of the year, South Georgia has the greatest

concentration of seabirds in the world, and most of them

arrive in the early spring.

Macaroni penguins make the most impressive entrants, over

five million pairs of them. They are the world's most

numerous penguin, and half of them are now here. The arrival is complete.

Courtship is next on South Georgia's busy spring schedule.

The wandering albatross has the most elaborate display.

These two are renewing their bonds after being months apart.

Wanderers pair up in their teens and can spend a further

50 years together, one of the longest partnerships in the

animal world.

By the middle of spring, the snows have cleared from the

coves and the loggos. The beaches are almost free of ice

too, but that isn't the biggest change facing the king

penguins. Their peaceful waterfront has turned into an

obstacle course of blubber.

The elephant seals have arrived.

This beach now contains a greater mass of animals than any other in the world.

The young seals were conceived here a year ago, and now that

they've been born, their mothers are ready to mate again.

The mating rights on this patch of the beach belong to a

beachmaster. His harem contains 50 females. Females that are

coveted by others.

His authority is being challenged.

This rival means business.

This could be the beachmaster's first serious test of his spring campaign.

The beachmaster himself weighs four tons, but this rival is his equal.

When these titans clash, bones crunch.

This is the first time I've seen this happen.

This is the first time I've seen this happen.

This is the first time I've seen this happen.

He has won the first battle, but he may have to defend his

harem every hour for the next month. If he can stay master

of his beach for this period, many of the young born here next year will be his.

It's the end of spring on the wandering albatross cliffs,

their season for fledging. Last year's chicks have lost

their fluffy down and step up to the challenge of getting into the air.

The albatross is not very competent on the ground, so until

it can fly, it isn't good for much. And this makes the

maiden flight the crucial event in an albatross's life.

Managing the largest wingspan in the world takes practice.

Lots of it.

Weeks can go by like this. Certainly the winds must be

right, but it does appear that for some the problem is

something of a mental one.

At last.

The southern ocean beckons. This bird's feet

will not touch land again for five years.

One thousand miles further south, on the edge of the

Antarctic continent, the sea ice is only just starting to

break. But the daily penguin's activities are certainly

warming up. The males have now finished their nests by fair

means or foul, and the females are finally returning just

as the weather is improving. Now their courtship can begin.

The eggs are laid. And the females leave the job of

incubating them to the males while they go fishing out on

the fragmenting sea ice.

Killer whales.

It's teamwork that makes killer whales so dangerous. And this is a big team.

And this is a big team.

And this is a big team.

And this is a big team.

And this is a big team.

And this is a big team. There is no real need for the

penguins to be alarmed. These killer whales are a kind that

only eats fish.

Rising out is simply the best way for the whales to work

out which tracks lead towards the coast and better fishing.

A new generation of Adelies steps forth into the short

Antarctic spring to be nurtured by industrious parents

who've taken great risks to give their young a head start.

They will need to grow fast if they are to fledge and leave

before the freeze sets in again. It's a battle they will win

or lose over the approaching summer.

To film the entire breeding cycle of the Adelie penguin,

frozen planet sent a team to one of the world's largest

colonies at Cape Crozier, Antarctica.

Cameraman Mark Smith and director Jeff Wilson plan to

spend the next four months living amongst the penguins in a

location first visited by the early explorers a century ago.

So arduous was Scott's winter expedition to Cape Crozier

that it became known as the worst journey in the world.

Modern means make Mark and Jeff's journey a more comfortable

affair, but once there, they will be tested to the very

limits of their endurance.

The pair arrive in early spring with enough supplies to

survive the next four months working alone in the Antarctic

wilderness.

Scott's legend of Cape Crozier tells of some extreme weather

to say the least. So Mark and Jeff take advantage of the

clear conditions in the knowledge that the Adelie's arrival is imminent.

But the next morning, things take a turn for the worse.

We've just come up to this ridge to go and check exactly

what it looks like down in the colony.

Even here you can hear a huge kind of roaring noise up on

the hill. Never really heard anything like that before.

Up there must be blowing up the most almighty gale and that

is, you know, just a mile away or something. So that means

that could get here very, very quickly. So, yeah, it makes

you slightly scared. Weird, isn't it? The winds here are

famously ferocious and with so little experience of this

location, Mark and Jeff retreat to the relative shelter of

their hut. I was just today thinking, well, it can't be too

bad because we haven't seen rocks start to blow around yet.

And just at that moment, it was like a rock took off and rolled down there.

Yeah, it's getting stronger. By the second day of the storm,

the winds reach 80 miles an hour and it's apparent that even

getting lunch from the outside larder is too risky. Yeah.

To their increasing alarm, the storm continues to build.

All afternoon it's been blowing about, it must have been 100

miles an hour and in the last half hour it's just got a lot

stronger. Aside from being absolutely terrified, Zia did

worry that our gear is stashed outside somewhere, that

we didn't have room for it in the hut. We just don't know

whether it's going to be there in the morning or not, which

is just about the end of our trip. On the third day of the

storm, the winds hit 130 miles an hour. The hut starts

to shake from its very foundations and Mark and Jeff's

situation becomes critical. The wind's so strong it's

constantly blowing the pilot light out on the parapet stove,

so the temperature's strong. The wind's rising. It's like

the bloody roof's coming off. The really scary thing is that

had we gone out down to the colony and tried to film today,

it's a very high likelihood that we'd be dead by now. And I

don't say that lightly, there's no way we would have

seen this through down there and that is quite sobering.

After four terrifying days inside the hut, the winds

finally drop and Mark and Jeff are keen to see what, if any,

equipment has survived. All the real important stuff, the

camera stuff, is all still here and it's still strapped to

this rock.

You have no idea how much joy that gives us. We can get on with our jobs now.

The first things to welcome us into the colony are

these skewers which come in and batter us from above.

At its height, the colony will swell to over half a million

penguins and in the 24-hour daylight of the Antarctic

summer, Mark and Jeff spend all of their waking hours

filming. Unpredictable weather continues to force the team

to climb the two miles back to the relative shelter of their

hut and Mark devises a novel way of testing the wind speed.

After six weeks, the first sign that the pair might be

tiring of their penguin neighbours. Over there's a leopard

seal. It's the first non-penguin looking animal in two

months. Look at that, it's a leopard seal. So I was down

here filming the penguins coming in, followed this penguin

that came out of the waves up the beach, very nice shot,

stopped the shot and there in the middle of the frame was

this completely white penguin trying to get into the shot.

We kind of suspect that he might be following us around now.

Working around the clock for this length of time in the

presence of half a million screaming penguins would test

anyone's resolve. I hate carrying gear. Hear that? I hate

carrying gear. I don't want to do it anymore. Midway through

their trip, after more than a thousand hours amongst the

penguins, their grip on reality is beginning to loosen. Here

we are on the Penguin Superhighway where the penguins go

down to the sea. It seems that they follow the American

system driving on the right, going down to the sea on the

right, going back from the sea on the left as you're facing

the sea. I'm fairly sure that yesterday they were doing the British system.

The legendary Cape Crozier weather soon snaps them back into

reality. We're just filming the penguins with this huge wind

storm coming over the ice cap. This is the kind of thing we

were warned about by the guy who was here before, who's been

here for several years and saying if you see skies like this

then you should run for home. But of course we're just going

to stay and film it because we're the BBC. But in this part

of the world, working for the BBC doesn't count for much.

Within minutes the winds reach hurricane strength and the

crew are in serious trouble. We've got an hour venture out

and go up about a mile up this valley which looks like it's

got about 80 mile an hour winds blowing down it. So it's

going to be quite an adventure. Bit frightening though

really. After three months the pair are now fully aware of

the strength the winds can reach. There is a very real

danger that they could be separated and lost in these

whiteout conditions.

Two terrifying hours later and their relief at finally reaching the hut is tangible.

With a month still to go at Cape Crozier, Mark, Geoff and

the penguins will face many more storms like this. But it

seems that their greatest challenge will be to maintain

their sanity. Here we are travelling through the Antarctic

by sled we're being pulled by a herd of huskies.

Twelve of them panting out front, breaths steaming from

their mouths. And as we go along we see the happy people

waving at us.

We're going to take off!