All language subtitles for Natures Great Events s01e01.eng

DAVID ATTENBOROUGH:
The power of the sun

drives the seasons,
transforming our planet.

Vast movements of ocean and air currents

bring dramatic change
throughout the year.

And in a few special places,
these seasonal changes

create some of the greatest
wildlife spectacles on Earth.

Here in the Arctic each summer,
the sun begins to melt the winter ice.

Nearly three million square miles of ice
will disappear,

opening up a narrow window of
opportunity for millions of animals.

For many, it's their best chance
to feed and breed.

But for polar bears,
it's the hardest time of the year.

They have to survive the greatest
seasonal change on the planet.

Winter in the Arctic.

The northern lights
flicker across the sky.

It's a land of continuous night

where temperatures plummet to minus 40.

Polar bears are in their element,

hunting for seals on the frozen sea.

But the long night is coming to an end.

In February the sun rises

for the first time in four months.

In the coming weeks
the strength of the sun

will power an enormous change.

But for now its rays offer
only a little warmth.

Despite the sun's return, six million
square miles of the planet's far north

is still cloaked in ice.

Deep snow covers the mountains.

Even the sea is frozen solid,
many metres deep.

Groups of ringed seals
haul out through holes in the ice

to bask in the weak sunlight.

(YELPING)

But they are vulnerable
and have to keep a lookout.

With the sea still frozen,
it's easier for predators to get close,

and the seal's greatest enemy
is the polar bear.

A mother bear and her four-month-old cub
are hunting.

Seals make up most of the bear's diet,

and to find them she must lead
her youngster out onto the ice

for the first time.

Scientists, looking at how
a changing climate is affecting bears,

have fitted the female
with a radio collar.

The ice here is thinner,

and she must spread her weight
to avoid breaking through.

For her cub, it's all just a game.

By sticking close to Mum,
he'll learn how she hunts for seals,

a critical lesson
for his future survival.

At this time of year
the frozen Arctic is empty of life

and only a few hardy residents
can survive.

For a female arctic fox,
the winter has been a time of hunger.

Food is scarce and she's had
to wander far and wide,

scavenging from the remains
of bear kills.

(YELPING)

But her fortunes are changing.

A dead reindeer is a lucky find.

If no other scavengers come along,

this could sustain her
for the rest of the winter.

With the sea frozen,
polar bears are busy hunting.

This bear has caught a seal.

He waited for it to surface
through a hole in the ice

and his patience has been rewarded.

He must catch a seal about once a week,
and this is the best hunting season.

As long as there is sea ice
the bears won't go hungry,

as walking on the ice is the easiest way
for a bear to get close to a seal.

But the ice will soon start to break up
and hunting will get harder.

The calories the bear takes in now

will have to see him
through hard times ahead.

For polar bears
it's the survival of the fattest.

At this time of year there are still
only five hours of daylight.

But as the sun rises higher,
each day lasts 40 minutes longer.

It's March, and with increasing sunlight

the first in a huge wave of migrants
are arriving.

Millions of seabirds are travelling
north to reach the frozen coast.

Huge flocks of little auks
and guillemots

fly across many miles of ice
from the nearest open water.

Their destination is
the still-frozen sea cliffs.

It's an inhospitable place,

but in a few weeks
everything here will change.

It pays to be early, even though
the snow has yet to melt.

The first arrivals get the best
nesting ledges and a head start.

(SQUAWKING)

They have just 50 days from
laying their eggs to raise their chicks.

(SQUAWKING)

The Arctic's silent wilderness
is coming to life.

It's three months since the sun's return
and its power is growing daily.

The air temperature rises slowly

and once above zero,
at long last, the melt begins.

Melting snow feeds freshwater streams
which pour off the land.

In just a few short days,
the melt unveils a whole new landscape.

The coastal cliffs
now teem with nesting seabirds,

and it's not long before
they attract unwelcome attention.

The fox's white winter coat
has disappeared with the snow.

Her new camouflage will allow her
to change from scavenger to hunter.

The short summer will be
her best chance to raise a family.

The snow may be
disappearing from the land,

but the sea ice has yet to melt.

The coastline is still locked in ice.

The islands of the Arctic

are surrounded by thousands of miles
of white frozen ocean.

Because the sea ice is so thick,
it won't begin to break up

until the temperature stays above zero
for a number of days.

Until then, few creatures can penetrate
this icy barrier.

The sun reflects from
the white frozen sea,

creating a desert of icy mirage.

The bear can still walk on the ice
to hunt for seals,

but not for much longer.

It's getting warmer by the day.

The bear's world is about to melt away.

It's now June and the sun beats down
24 hours a day.

The temperature remains constant
above zero degrees.

The frozen sea begins to melt.

Pools form across the surface,
absorbing more of the sun's heat,

speeding the thaw.

Sunlight penetrates the frozen surface,

illuminating a strange world
beneath the ice.

The frozen barrier has split.

Mysterious voices echo
against the icy ceiling.

Giant cracks, or leads,
form at weak points,

creating a pathway for new arrivals.

Narwhal.

Known as the arctic unicorn
because of their strange spiral tusks,

narwhal are some of
the most secretive and elusive animals

in the world's oceans.

The leads provide passage for thousands
of these mysterious whales.

Each summer they travel 600 miles north,

navigating through the ice
to reach rich fishing grounds.

More whales travel along the edge
of the ice where it meets the open sea,

to search for the openings of leads.

It's a hazardous journey.
As mammals, they need air to breath

and if the ice closes above them
they could suffocate.

They're looking for holes in the ice
where they can surface.

A single breath
will last them for 1 5 minutes.

The further they travel, the harder it
becomes to find holes in the ice.

They snatch a breath and then travel on.

But ahead, the ice forms
an impenetrable barrier.

The narwhal use their heads
and their long tusks

to break the ice
and enlarge the breathing holes.

For now they've reached a dead end
and must wait.

The ice will need to melt further
if they are to continue.

All across the Arctic
the sea ice is beginning to retreat.

The leads widen,
forming tracts of open water.

Wind and ocean currents
shift the loosening ice, breaking it up.

As the ice melts, thousands of miles
of open ocean become accessible,

providing a bonanza
for millions of seabirds.

In just four weeks
a colony of guillemots

can devour one and a half
million tonnes of arctic fish.

As the ice melts, their journey to
their feeding grounds in the open sea

shortens by the day.

They gather at the edge
of the retreating ice

and dive to hunt
for arctic cod and capelin.

The shoals are found 80 metres down
in the murky depths,

and the guillemots must hold
their breath for nearly two minutes.

With their crops stuffed with fish,
they return to the colony

to feed their hungry youngsters.

(YELPING)

With 24 hours of daylight,
they go on fishing around the clock.

Warmed by the sun
and driven by winds and currents,

the sea ice is now fragmenting.

That is a big problem
if you need the ice to hunt from.

A polar bear can smell a seal
from over a mile away.

(SNIFFS)

But the prey he depends on
is hard to find

in this constantly moving landscape.

He must take to the water to navigate
through the drifting maze of ice.

Bears are excellent swimmers,
but he's no match for a seal.

As the ice melts,
finding seals gets harder

and with more open water,
it's easier for a seal to escape.

The melt has caused a shift in power.

Now it's ''advantage seal''.

The bear's chance has slipped away,
and his hunger grows.

The ice barrier broken,

strange marine visitors begin to arrive.

They've swum 600 miles to get here,
and with the ice gone

they can make their way into
the shallows of freshwater estuaries.

(CLICKING)

Beluga whales.

As more and more belugas arrive,

a strange annual ritual begins.

For belugas, this is
a very special event.

The violent thrashing against the
river bed loosens their year-old skin

and rids them of unwelcome parasites

they may have picked up
on their journey.

In freshwater,
warmed by the strengthening sun

and with the smooth
pebbles in the shallows to rub against,

the whales whistle with pleasure.

(ALL WHISTLING)

But the ice-free summer will be short.

The whales can only enjoy
their arctic spa for two weeks.

Soon the belugas must leave the shallows

and make the most of
what's left of the summer

to hunt the shoals of arctic fish.

It's early July,

and at the bird cliff
the fox has caught a nesting fulmar.

She has a family now,
eight tiny mouths to feed,

and one bird is not enough to go round.

The cubs bicker over their dinner.

They're only three weeks old
and in just another two weeks

they'll have to be ready
to fend for themselves.

(YELPING)

The winter ahead will be so harsh that
only two of these eight cubs

are likely to gain enough weight
to survive.

Their lives depend on every mouthful.

(YELPING)

When food is scarce
the most dominant cub will feed.

And the smallest will go hungry.

The seabirds have been working
round the clock to keep their chicks fed

and to prepare them for
the first big challenge of their lives.

If they are to escape the winter,

they'll have to leave the cliffs
right away, and get far out to sea.

But it's only been 20 days
since they hatched

and their wings are
still too weak for them to fly.

So far their feet
have never left the ground

and there is only one way down
to the safety of the sea,

300 metres below.

Reluctantly, the chicks take
a few nervous steps towards the edge.

Encouraged by a gentle nudge,

he leaps into the unknown.

Dad follows right behind him,
reassuringly calling to his chick.

(SQUAWKING)

Made it.

The landings may not be stylish,
but at least they're on target.

(SQUAWKING)

It's easy to misjudge the distance
and some fall short of the water.

But even now, Dad sticks close by.

He encourages his chick
to take the last few steps

towards the safety of the waves.

But some chicks
land a long way from the water.

They're sturdy enough
to survive the fall,

but this is no place to be left alone.

For the mother fox it's easy pickings.

With so many free meals
falling from the sky,

she runs from one kill to the next.

The chicks will be jumping
for only three days,

so she must make the most
of this bonanza.

The survival of her own family
depends on it.

With more chicks
than she can possibly carry,

the mother fox has to be clever.

What her family can't eat now,
she buries.

For the days ahead
she'll have a well-stocked larder,

enough for all eight of her cubs.

Their bellies now full at last,
the cubs can relax in the sun.

For the guillemot chicks that survive,
the ordeal has only just begun.

They must retreat south 600 miles,
beyond the reach of winter.

But the youngsters can't fly yet,
their wings aren't strong enough.

So, led by their parents,
they'll have to swim.

(SQUAWKING)

At the height of summer
even the permanent ice caps

are touched by the power of the sun.

Melt-water, channelled down
from high on these ice caps,

pours over a precipice
where the ice meets the ocean.

Along this 200-mile wall of ice,

a thousand freshwater cascades
plummet into the sea.

As July draws on,
the great melt reaches its peak.

The greatest seasonal change
on the planet has taken place.

The sea ice that once extended
all the way to the horizon

is now open ocean.

In just three months, the sun has won
its battle with the ice.

Over two and a half million square miles
of ice has melted away,

uncovering thousands of islands
surrounded by open ocean.

But in recent years, the scale
of this melt has been growing.

And for one animal
this is a critical issue.

A mother bear and her adolescent cub

rest on a fragment of sea ice.

With the melt, they're forced
to swim ever-greater distances

to hunt for seals.

Their arctic home is increasingly
vulnerable to a changing climate,

and this year there has been
even less ice than normal.

If future melts
are as extreme as this one,

bears like these
may starve or drown, lost at sea.

This is one of the last pieces of ice
now adrift in the open ocean.

The polar bear's icy world
has melted away.

For many others the open water
provides the greatest feast of the year.

The narwhal have
made it through the ice.

They gather in bays where they can hunt
for arctic cod and squid.

Here they are joined
by other ocean migrants.

Bowhead whales.

These 1 00-tonne giants
feed on millions of tiny plankton

that flourish in the sunlit waters.

Belugas have come for the rich fishing

and rest on the surface between dives.

Even on the sea bed
there is plenty on the menu.

Two tonnes of pulsating blubber

forages for clams in the sediment.

Walrus are year-round residents
of the Arctic,

following the ebb and flow of the ice.

In the open summer waters they
can reach huge areas of the ocean floor,

rich feeding grounds
for these giant seals.

They hoover up clams
with their rubbery lips.

A single walrus can eat up to
4,000 clams in one 1 0-minute dive.

Bellies full, they come up for air.

With the sea ice gone,
the walrus haul out on dry land to rest.

(BELLOWING)

They're used to huddling together
to keep warm,

and even now that
it's 1 2 degrees above freezing,

they prefer to stick close together.

In the warmth of the sun, the walrus
begin to shed their old skin,

and they spend hours scratching.

Some places are
harder to reach than others.

(GRUNTING)

These irritations make them bad-tempered
and arguments often break out.

(BELLOWING)

(SNORTING)

Spitting, stabbing and bellowing
iron out any disagreements.

(SNORTING)

All disputes settled,
a peace of sorts returns once more.

Digesting a belly full of clams
generates a lot of wind,

making walrus colonies
very fragrant places.

(FARTING)

Fed by the abundant supply
of guillemot chicks,

all eight fox cubs seem to have
boundless energy.

Soon they will be ready to face
the world without their mother.

In just five weeks
she's raised her cubs,

making the most of the short summer.

The mother fox has won
her race against time.

Between June and July, the Arctic
is the land of the midnight sun.

An empty wilderness
has been transformed.

(CHIRPING)

The once-frozen ocean
is now bursting with life,

as all the animals
enjoy the summer feast.

(CLICKING)

But polar bears aren't so fortunate.

With no sea ice to hunt on,
they're now trapped on dry land.

A hungry bear will eat any food
it can get its paws on,

but for a meat-eater
a few scraps of dry lichen won't go far.

It may have been four months
since his last kill

and he won't find any seals here.

If the yearly increase
in the scale of the melt continues,

more bears will starve.

Two thirds of the world's polar bears
could vanish by 2050.

The great melt has always
been difficult for bears,

but soon surviving the summer
may become impossible.

The scale of the summer melt has changed
over the last 30 years.

2007's melt broke all records.

400,000 extra square miles of ice
disappeared,

the greatest melt ever recorded.

The latest predictions suggest that
the Arctic may be entirely ice-free

in summertime within 20 to 40 years.

By September, the sun's power
begins to ebb.

The summer comes to an end
and the Arctic empties of life.

The last seabirds
begin their long journey south,

leaving only a few
hardy residents behind.

The fox cubs now face
the changing season alone.

Already, the first snow
is beginning to fall.

The full Arctic winter
is just six weeks away.

For hungry bears,
six weeks may be too long to wait.

The sea ice will not freeze properly
till it reaches minus 2 degrees.

For now, it's still too warm.

This ice is no use to the bears.
They can't walk on it to hunt.

The normally unsocial bears
gather in groups,

trapped on the shoreline.

This is the time of year
the male bears spar.

(GROWLING)

Only the biggest bears have
the energy reserves to fight.

After a summer without food,
the bear's systems are in low gear.

These aerobics help warm them up,

in readiness for
the winter hunting ahead.

(GROWLING)

It's late October,
but still the sea hasn't frozen.

For every degree rise
in the average temperature,

the summer melt is extended
by a whole week.

That's more bad news for polar bears.

Smaller, younger bears don't have
the energy of the big males.

Each day they are without food,
they lose nearly a kilo.

Some have lost
half of their body weight.

These hungry bears must now rest
in the snow and conserve energy.

All they can do is wait.

At last the wind changes,

blowing from the cold north
across the sea.

The air temperature
plummets to 20 degrees below.

It's now cold enough
for ice crystals to form in the ocean.

They knit together
forming a greasy layer of surface ice.

This thickens into plates

which bump and collide in the swell,
forming pancake ice.

These pancakes lock together
to form a continuous surface.

At long last the sea has frozen.

Only now can the bears head out
onto the sea ice to hunt for seals.

But the new ice has a surprise in store.

(ICE CRACKING)

This season,
for the first time ever recorded,

even the winter ice is thinner.

The ice here is too thin to climb out on

and he struggles to free himself.

At last, safely on the firmer ice,

he rolls in the snow to dry his fur.

In November, the sun sets
over the frozen north.

It will not appear again
for four months.

The summer melt provides opportunities
for millions of animals,

but has now become a threat
to the polar bear's very survival.

This season, the bear has survived
the greatest melt yet recorded

and made it through
to the Arctic winter.

The frozen Arctic sea is one of
the most demanding of all environments,

and the location
for a rarely seen spectacle.

The Nature's Great Events team

wanted to film the annual migration
of the elusive arctic narwhal.

To do so, they would have to live on,
dive beneath and fly over the ice

during the climax of the great melt.

The quest for the narwhal started
at the height of the melt, in July,

when the sea ice
was at its most dangerous.

This made the task of first finding
the whales a tough prospect.

This is rough ice. And we're stuck.

ATTENBOROUGH: Narwhal are so elusive

and the conditions working
on the ice so difficult,

that the crew allowed a month
to track them down.

The plan was to get to
the edge of the ice

in the hope of finding the whales
at the beginning of their migration.

The melt was in full swing and
the team were in the thick of it.

With 24-hour sunlight, the leads
along which the narwhal migrate

were getting wider every day.

After three weeks of searching,

the whales were living up
to their secretive reputation.

The crew couldn't see the narwhal,

but there was evidence that
they were not far away.

A sensitive hydrophone enabled
them to eavesdrop on the whales

under the ice.

I am hearing what could be
sedation whistles and clicks.

So it could be narwhal.

It's very distant and sound travels
a long way under water,

so these guys are probably still far
away, but it's a good sign. It's good.

ATTENBOROUGH:
They could hear the whales,

but would they be able to see them?

By now the cracks had opened wide enough
for them to dive to search for them.

Ice diving is dangerous
at the best of times,

but in such a remote location,
days away from the nearest help,

they had to be especially careful.

Even though it was
the height of the summer,

the icy sea water was still
a chilly minus 1 .6 degrees.

So the team needed
not only specialist equipment

but specialist attitude.

You're very quiet there, Tom.

Well, I was just thinking
we don't really want the ice to close up

while we're underneath it.

No, closing up would be a bad thing.

-It would be a bummer.
-Yes.

ATTENBOROUGH: And Tom from Florida
was taking no chances against the cold.

Ah, that feels really good.

(CHUCKLING)

Sam, we gotta do this more often.

Wha-hey!

ATTENBOROUGH:
Now they were in the whales' realm.

A vast underworld of frigid water

enclosed beneath a ceiling of ice.

This is a world we rarely see.

Sinister, but at the same time
uniquely beautiful.

As the melting ice runs into
the open cracks,

it creates an underwater mirage

as the layer of freshwater mixes with
the denser saltwater beneath it.

If the ice were to close in on them now
they could get trapped.

As they ventured deeper, the crew
carried a lifeline to the surface

to guide them back
to their opening in the ice.

Sadly, there were no narwhal to be seen,

but it was a unique glimpse
of the whale's world.

Sometimes it's a little bit spooky
to have a ceiling above your head,

and then when the tank starts
breaking through a little bit

once in a while you think,

''Is this really an intelligent thing
to be doing?''

But the shot looked cool,
so I think it was worth it.

ATTENBOROUGH: They had spent
over a month on and under the sea ice.

But with still no shots of narwhal,
time and ice were running out.

The edge of the ice was now
only 1 5 centimetres thick,

barely enough to support the weight
of a man, let alone a camera team.

You can feel the swell just coming up
underneath this ice, it's pretty trippy.

It's just a gentle undulation
all around.

This won't be here tomorrow.

ATTENBOROUGH: But just as
the ice was getting too thin,

their effort was rewarded.

-What do you see, Sam?
-Narwhal.

See where the five guillemots are
out there on the water, six guillemots?

ATTENBOROUGH:
Tom and his team had found the narwhal.

The whales had arrived at long last.

But sadly, the ice was now
too dangerous to film from.

If they were to stand any chance
of continuing to film,

it was time to call for reinforcements.

After being stranded for seven days
due to bad weather,

the helicopter crew
finally arrived, just in time.

There was now one last chance
to film the narwhal, from the air.

Armed with an advanced
aerial camera system,

they could zoom in on the action
from a long distance away.

This would enable them
to find the whales

and even get close-up shots
without disturbing them.

As the ice team headed home,
the helicopter team took over.

The helicopter could only carry
enough fuel for a few hours' flying,

and finding the whales in this
vast landscape was a daunting task.

But at last they caught up
with the magical arctic unicorn.

PILOT: Yeah, there they are.
They're kind of 1 0 o'clock from me.

Just coming under us now.

ATTENBOROUGH: Unaware of
the helicopter flying high above,

the whales carried on
their journey through the ice.

This is the first time the narwhal
migration has been filmed

from this incredible aerial perspective.

The plan had worked.
It had taken over six weeks,

but the team had managed to film
the amazing journey of the narwhal

in this most harsh
and testing of landscapes.

It was a rare and magical insight

into the life of one of our planet's
most mysterious creatures.

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