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The frozen seas
are worlds unto themselves.

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Beneath their ceiling of ice,

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they have an eerie,
almost magical stillness,

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cut off from the storms
that rage above.

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In the winter, the feeble slanting
rays of the sun bring little warmth

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and the temperature seldom rises
above minus 50 degrees Centigrade.

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(HOWLING, WHISTLING WIND)

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For much of the year,
it is dark and cripplingly cold.

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Yet, there IS life here
at BOTH ends of the earth —

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the Arctic and the Antarctic.

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For most animals, whether
they live in or out of water,

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the winters,
when much of the sea is frozen,

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bring the greatest challenge.

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The northern hemisphere.

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It's February,

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and as the earth tilts on its axis,

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the sun's rays
creep slowly northwards

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and the Arctic emerges
from its harsh winter.

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The Arctic is a frozen ocean
surrounded by continents,

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and when the surface of the sea
between the continents

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freezes from shore to shore,

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land predators walk out onto it

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to hunt.

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It's early March,

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and the sea is still covered
with ice...

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But there are patches
of open water — polynyas —

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that never freeze over.

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Here, where tidal currents
are squeezed between islands,

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the water movement is so strong
that ice cannot form.

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Walruses spend the winter
in polynyas.

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Here they have permanent access
to the air,

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but they can also retreat
to the sea to shelter, to hunt.

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Other sea mammals overwinter
in polynyas as well— in this one,

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a young bowhead whale.

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Here, the current is really fast

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and the shifting ice is dangerous.

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This whale became trapped

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when ice encircled it last autumn.

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There is no food here,

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but a whale must breathe,

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and the only place it can do so
for miles around is in this tiny hole.

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It's living entirely
on its reserves of fat,

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but now, they're dangerously low.

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It will be some months yet
before it can escape.

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Elsewhere, other whales
have also been trapped.

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These are belugas.

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Their tiny hole in the ice

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has been kept open not by currents,

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but by the belugas'
continuous movements

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as they rise to breathe.

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Open water is now
some 20 miles away.

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It will be two months yet
before the ice melts.

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The belugas are extremely thin

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and most of them
are horribly scarred.

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But their wounds
were not inflicted by the ice.

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A whale would be a huge prize
for any meat—eating hunter,

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and these belugas,
trapped by the ice,

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are within reach of polar bears.

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Well aware of the danger,

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the belugas stay submerged
as long as they can,

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but they can only hold their breath
for about 20 minutes.

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Catching a four—metre—long whale
that weighs one tonne

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is no easy task,

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even if that whale
is weakened by starvation.

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But a beluga
is well worth waiting for.

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Day by day,
as the hole gets bigger,

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it becomes increasingly difficult
for the bear to land a whale.

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Keeping its fur in good condition
and free from salt

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is important for warmth,

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and the bear uses snow
like blotting paper.

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These belugas have been attacked
by many bears

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over the last six months,

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and some have been caught.

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It may have taken a long time
and a lot of patience,

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but a catch when it's made
brings abundant rewards

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of energy—rich blubber.

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Gulls rely on bear kills
at this time of the year,

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and the colour of blood
staining the ice

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attracts them from a long way away.

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The remaining belugas
still have a long wait

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before they're released
from their prison

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and the threat of slaughter.

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Arctic foxes
also rely on the polar bears

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to hunt on their behalf.

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They're the jackals of the north,

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and scavenge from bear kills
whenever they can.

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In winter and early spring,

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they're wholly dependent on bears.

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Only in the summer,
when the sea ice melts,

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will they regularly catch prey
for themselves.

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They're not strong enough
to tackle adult seals,

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but can certainly take
new—born pups or birds.

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This canny individual

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is going to bury its prize.

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It may need it
during the uncertain times ahead.

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The presence of bears

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affects the behaviour of almost all
the animals here, big and small.

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The bears tend to avoid
the fringe of fragmented ice

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bordering open water

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where travelling
can be very laborious,

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but that very fact
makes this area — the pack ice —

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a particularly good place

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for seals to pup.

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Harp seals breed here.

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Their pups are born with white coats

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which camouflage them
very effectively against the snow.

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Harp seals have
a very short nursing period —

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a necessity
on this unstable pack ice —

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but suckling is intensive.

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The pup feeds for just 12 days

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on milk that is 45 per cent fat.

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Then it's abandoned

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and has to fend for itself.

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A male hooded seal.

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This impressive nasal display

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is used to warn away other males...

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and to win a mate.

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Hooded seals also breed
on pack ice.

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Their pups suckle
for only four days,

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the shortest nursing period
known for any mammal,

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and all because
the threat of polar bears

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caused them to breed
on the unstable ice.

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Another Arctic seal opts
for the solid ice further north.

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Because it's easy for bears
to hunt here,

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these ringed seals
must be particularly vigilant

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and have to hide their pups.

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Ringed seals
are comparatively small,

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so they can give birth
to their pups

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in little caves or lairs
under the snow.

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Here, a pup is out of sight

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and protected from bad weather.

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In late March and into April,

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female bears emerge from
winter dens with their new cubs.

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The mother has not eaten
for at least five months

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and she's hungry — very hungry.

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If she doesn't succeed in catching
a regular supply of seals,

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her milk will fail

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and her cub will die.

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Bears have an extraordinarily
sensitive sense of smell

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and can detect seal pups
hidden in the snow

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from two kilometres away.

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But a female ringed seal
uses several lairs

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and a bear will have
to break into a number

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before it finds one
that is occupied.

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This is a crucial time for the cub.

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By watching its mother hunt

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and by copying her actions, it's
beginning to acquire the rudiments

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of its own hunting skills.

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Play is also important
for developing muscles

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and improving co—ordination.

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As the days go by,

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the sun rises higher and remains
above the horizon even at night.

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The female bear continues to hunt

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until her cub is too tired
and can't keep up.

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She's smelt something.

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The pup escapes
through a hole in its lair

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that leads to the sea below.

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Only one in 20 hunts is successful,

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but this mother
must find a seal pup soon

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if her cub is not
to starve to death.

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As spring turns into summer, the sun's
heat begins to melt the sea ice.

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Now, the ocean is accessible

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and the Arctic's summer visitors
return.

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Migrating birds

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arrive from the south

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to nest and feed on the seafood
now within their reach.

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Brunnich's guillemots

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are the northern equivalent
of penguins,

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but they have retained
the power of flight

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for they need to reach cliff ledges

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where their nests will be safe
from predatory bears and foxes.

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Nonetheless, they are as at home
in the water as in the air.

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They dive down
to a depth of 50 metres or more

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to catch fish.

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00:17:20,400 --> 00:17:22,915
In June, the ice begins to fracture.

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The cracks — or leads —

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form useful corridors of open water

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for air—breathing animals.

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Belugas, migrating
to their feeding grounds,

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00:17:36,920 --> 00:17:40,914
use these leads to penetrate
the ice—covered seas and reach areas

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00:17:41,080 --> 00:17:45,074
where their preferred food,
Arctic cod, has spent the winter.

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00:17:51,800 --> 00:17:56,511
The males regularly dive
to about 500 metres to find fish.

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The females and young,
which have smaller lungs,

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only go to about 350.

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00:18:14,800 --> 00:18:18,396
In late June and July,
narwhals arrive.

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The females,
who usually lack tusks,

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come first with their new calves.

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The males follow a little later.

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They also move up the leads

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in search of fresh feeding grounds.

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Bowheads. Up to 18 metres long

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and weighing 100 tonnes.

193
00:19:02,320 --> 00:19:04,312
These are the only large whales

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00:19:04,480 --> 00:19:06,915
that stay in the Arctic
all year round.

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00:19:22,800 --> 00:19:24,519
They are not after fish.

196
00:19:24,680 --> 00:19:26,990
They're seeking smaller prey.

197
00:19:28,200 --> 00:19:31,876
Despite having the largest mouths
in the animal kingdom —

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00:19:32,040 --> 00:19:34,032
the size of a small garage —

199
00:19:34,200 --> 00:19:36,635
they eat tiny crustaceans —
copepods —

200
00:19:37,160 --> 00:19:39,152
straining them from the water

201
00:19:39,320 --> 00:19:41,994
with the four—metre—long strips
of baleen

202
00:19:42,160 --> 00:19:44,231
that hang from their upper jaws.

203
00:19:52,480 --> 00:19:54,995
In the summer,
they store enough energy

204
00:19:55,160 --> 00:19:57,834
to last them
through the following winter

205
00:19:58,000 --> 00:20:00,071
when food will be less abundant.

206
00:20:02,480 --> 00:20:04,199
As the ice melts away,

207
00:20:04,360 --> 00:20:07,114
the polar bears are forced
to head for land.

208
00:20:09,560 --> 00:20:11,552
They are excellent swimmers,

209
00:20:11,720 --> 00:20:15,873
and can cover 100 miles
of continuous open water if need be.

210
00:20:51,680 --> 00:20:53,672
Off east Greenland,

211
00:20:53,840 --> 00:20:57,390
there is little ice left by August,
so walruses haul out

212
00:20:57,560 --> 00:20:59,279
to rest on land.

213
00:20:59,440 --> 00:21:01,830
At this time of year,
they are moulting,

214
00:21:02,000 --> 00:21:05,914
getting rid of their old,
scarred, parasite—ridden skin.

215
00:21:16,360 --> 00:21:20,320
A bathe in cold water brings
some relief from the itching...

216
00:21:38,520 --> 00:21:40,512
but even there,

217
00:21:40,680 --> 00:21:43,240
the odd scratch is irresistible.

218
00:22:02,000 --> 00:22:05,437
They make daily excursions
out to deeper water.

219
00:22:15,560 --> 00:22:17,074
Down at 20 metres,

220
00:22:17,240 --> 00:22:19,391
they root around in the sediment,

221
00:22:19,560 --> 00:22:21,631
using their sensitive bristles

222
00:22:21,800 --> 00:22:24,031
to search out soft—shelled clams.

223
00:22:43,000 --> 00:22:44,798
Once they find a clam,

224
00:22:44,960 --> 00:22:47,111
they suck its flesh from the shell

225
00:22:47,280 --> 00:22:49,795
with their powerful,
muscular mouths.

226
00:22:53,040 --> 00:22:56,397
Walruses can feed for
about five minutes at this depth

227
00:22:56,560 --> 00:22:59,951
before they have to return
to the surface to breathe.

228
00:23:07,280 --> 00:23:11,593
Elsewhere in the Arctic, belugas are
gathering in their thousands.

229
00:23:11,760 --> 00:23:15,310
They congregate
in just a few large estuaries.

230
00:23:18,000 --> 00:23:20,993
Belugas of all ages and sizes
come here.

231
00:23:21,480 --> 00:23:23,551
There are even young calves.

232
00:23:35,360 --> 00:23:36,874
Some are so young —

233
00:23:37,040 --> 00:23:39,032
born only a week or so ago —

234
00:23:39,200 --> 00:23:40,793
that they need help.

235
00:23:40,960 --> 00:23:43,111
They swim on their mothers' backs

236
00:23:43,280 --> 00:23:45,670
so that they can breathe
more easily.

237
00:23:56,360 --> 00:23:58,591
As the tide moves up the estuary,

238
00:23:58,760 --> 00:24:00,274
the belugas follow,

239
00:24:00,440 --> 00:24:03,274
swimming into surprisingly
shallow water.

240
00:24:10,440 --> 00:24:11,920
Like walruses,

241
00:24:12,080 --> 00:24:13,958
they also need to moult.

242
00:24:22,000 --> 00:24:24,231
A combination of warm fresh water

243
00:24:24,400 --> 00:24:28,189
and vigorous rubbing
against the gravel does the trick.

244
00:24:39,360 --> 00:24:41,158
They remain here for days

245
00:24:41,320 --> 00:24:42,800
or even weeks,

246
00:24:42,960 --> 00:24:45,350
so it's likely that socialising

247
00:24:45,520 --> 00:24:47,557
is also important to them.

248
00:24:53,400 --> 00:24:57,110
After moulting,
they head back out to sea to feed.

249
00:25:03,000 --> 00:25:04,514
It's now autumn,

250
00:25:04,680 --> 00:25:07,718
and the sea begins
to freeze over once again.

251
00:25:13,400 --> 00:25:15,869
Thin sheets of ice form
at the surface

252
00:25:16,040 --> 00:25:17,918
and pile up, layer upon layer,

253
00:25:18,080 --> 00:25:21,073
gradually creating
an impenetrable barrier.

254
00:25:29,400 --> 00:25:35,032
By late November, the Arctic ocean
is sealed once again by ice.

255
00:25:49,200 --> 00:25:51,237
The lights of the aurora

256
00:25:51,400 --> 00:25:53,357
play in the winter sky.

257
00:26:03,960 --> 00:26:07,271
And at the other end
of the planet — in the Antarctic —

258
00:26:07,440 --> 00:26:09,432
there is the southern aurora.

259
00:26:24,880 --> 00:26:27,475
Antarctica is now
emerging from winter.

260
00:26:28,360 --> 00:26:31,512
This is the coldest,
windiest place in the world.

261
00:26:31,680 --> 00:26:35,515
Temperatures are still hovering
at a numbing minus 50,

262
00:26:35,680 --> 00:26:38,673
and the returning sun
has virtually no warmth.

263
00:26:39,440 --> 00:26:43,514
Very few animals can survive
such extreme conditions...

264
00:26:45,000 --> 00:26:47,959
but Emperor penguins can.

265
00:26:48,120 --> 00:26:50,112
(HOWLING, ROARING WIND)

266
00:26:53,720 --> 00:26:55,712
Standing on the frozen sea,

267
00:26:55,880 --> 00:26:59,191
they endure the full force
of the Antarctic storms.

268
00:27:08,200 --> 00:27:10,237
Only by huddling together

269
00:27:10,400 --> 00:27:13,677
can they survive
the appalling winter months.

270
00:27:19,480 --> 00:27:23,554
They take it in turns
to bear the brunt of the gales.

271
00:27:25,480 --> 00:27:27,472
They can only live here at all

272
00:27:27,640 --> 00:27:31,634
because Antarctica is surrounded
by the great Southern Ocean

273
00:27:31,800 --> 00:27:34,713
and no land predators
have been able to reach it,

274
00:27:34,880 --> 00:27:36,872
so, unlike Arctic animals,

275
00:27:37,040 --> 00:27:39,635
they're not threatened
by polar bears.

276
00:27:43,000 --> 00:27:44,719
The sea is still frozen,

277
00:27:44,880 --> 00:27:48,112
but one seal, nonetheless,
manages to stay here,

278
00:27:48,320 --> 00:27:51,518
even throughout the winter —

279
00:27:54,600 --> 00:27:56,159
the Weddell seal.

280
00:28:10,600 --> 00:28:14,310
Underwater, it's protected
from the storms above,

281
00:28:14,480 --> 00:28:17,075
but it must have access
to the air all year

282
00:28:17,240 --> 00:28:19,118
in order to breathe.

283
00:28:30,000 --> 00:28:32,993
And they keep
their breathing holes open

284
00:28:33,160 --> 00:28:34,753
with their teeth.

285
00:28:45,000 --> 00:28:47,834
Only by continually
scraping away at the ice

286
00:28:48,000 --> 00:28:50,356
can they maintain access
to the air,

287
00:28:50,520 --> 00:28:53,831
but that means that their teeth
get badly worn down.

288
00:28:54,160 --> 00:28:57,551
Then, they can no longer hunt
and eat effectively.

289
00:28:57,720 --> 00:29:00,280
Weddell seals die young.

290
00:29:08,960 --> 00:29:11,236
The continent of Antarctica

291
00:29:11,400 --> 00:29:13,392
is so isolated and so high —

292
00:29:13,560 --> 00:29:16,029
almost 5,000 metres in places —

293
00:29:16,200 --> 00:29:19,272
that it's considerably colder
than the Arctic.

294
00:29:22,000 --> 00:29:25,311
Ice slides slowly down
from its centre

295
00:29:25,480 --> 00:29:27,870
towards its rim
in immense glaciers.

296
00:29:30,400 --> 00:29:34,314
During winter, the continent
effectively doubles in size

297
00:29:34,480 --> 00:29:36,073
as the sea freezes over.

298
00:29:36,240 --> 00:29:38,835
Ice forms around its shores

299
00:29:39,000 --> 00:29:41,754
and extends outwards
for hundreds of miles

300
00:29:41,920 --> 00:29:43,912
around the entire land mass.

301
00:29:49,560 --> 00:29:53,474
Under the sea ice live small
shrimp—like creatures — krill.

302
00:29:53,640 --> 00:29:56,599
They have been here all winter.

303
00:29:58,800 --> 00:30:00,996
During these dark months,

304
00:30:01,160 --> 00:30:04,073
they feed by scraping algae
from the ice.

305
00:30:06,800 --> 00:30:09,190
Remarkably, they also shrink in size

306
00:30:09,360 --> 00:30:12,512
and revert to their juvenile form
to save energy.

307
00:30:19,720 --> 00:30:22,280
As the temperature rises in spring,

308
00:30:22,440 --> 00:30:24,193
the ice begins to melt,

309
00:30:24,360 --> 00:30:27,751
and little air bubbles
trapped within it are released.

310
00:30:27,920 --> 00:30:30,719
Microscopic algae grow
around these bubbles

311
00:30:30,880 --> 00:30:32,872
and the krill now graze on them,

312
00:30:33,040 --> 00:30:35,874
gathering them up
with their beating legs.

313
00:30:52,240 --> 00:30:54,232
As the sun's rays grow stronger

314
00:30:54,400 --> 00:30:56,960
and penetrate deeper
into the water,

315
00:30:57,120 --> 00:30:59,430
floating algae begin to flourish,

316
00:31:00,480 --> 00:31:02,631
and krill leave the dwindling ice

317
00:31:03,040 --> 00:31:04,838
and gather in swarms

318
00:31:05,000 --> 00:31:06,992
as they harvest this new crop.

319
00:31:16,760 --> 00:31:18,240
Far to the north,

320
00:31:18,400 --> 00:31:20,392
beyond the blanket of sea ice,

321
00:31:20,560 --> 00:31:22,074
chinstrap penguins

322
00:31:22,240 --> 00:31:25,074
have been overwintering
in the open ocean.

323
00:31:32,240 --> 00:31:34,232
The occasional iceberg

324
00:31:34,400 --> 00:31:36,471
gives them the chance of a rest —

325
00:31:36,640 --> 00:31:38,632
if they can get onto it.

326
00:32:07,160 --> 00:32:10,392
But at this time of year,
where they really want to be

327
00:32:10,560 --> 00:32:11,960
is on land.

328
00:32:12,120 --> 00:32:15,557
It's just getting there
that's tricky.

329
00:32:33,200 --> 00:32:37,035
It's spring, and the penguins
are returning to breed.

330
00:32:43,720 --> 00:32:47,350
Their need to get ashore
is now urgent and imperative.

331
00:33:00,440 --> 00:33:03,000
Doing so is all a matter of timing,

332
00:33:03,160 --> 00:33:05,152
and picking the right wave.

333
00:33:52,160 --> 00:33:54,595
But their journey
has only just begun.

334
00:33:55,160 --> 00:33:57,675
Most of them will have to walk
many miles

335
00:33:57,840 --> 00:34:00,071
before they can find a nest site.

336
00:34:09,120 --> 00:34:11,510
(TREMENDOUS DIN)

337
00:34:15,080 --> 00:34:17,197
This is Zavodovski Island,

338
00:34:17,360 --> 00:34:20,592
which has the largest
penguin colony in the world.

339
00:34:21,880 --> 00:34:24,554
About two million chinstraps
breed here,

340
00:34:24,720 --> 00:34:27,838
and they come to THIS island
for a good reason.

341
00:34:33,400 --> 00:34:35,392
It's an active volcano.

342
00:34:35,560 --> 00:34:38,712
The heat from the crater
and the fumeroles

343
00:34:38,880 --> 00:34:41,634
keeps the slopes
free from the ice and snow,

344
00:34:41,800 --> 00:34:45,396
allowing these chinstraps
to start breeding earlier

345
00:34:45,560 --> 00:34:47,358
than those further south.

346
00:34:49,960 --> 00:34:51,440
But then again,

347
00:34:51,600 --> 00:34:55,310
living on an active volcano
is not without its risks.

348
00:34:57,120 --> 00:34:58,634
Unlike the Emperors,

349
00:34:58,800 --> 00:35:02,430
these penguins are able to lay
their eggs on the bare ground.

350
00:35:02,600 --> 00:35:06,389
Little wonder so many choose
to brave the mountainous waves

351
00:35:06,560 --> 00:35:08,040
in order to get here.

352
00:35:14,600 --> 00:35:16,910
Further south, near the continent,

353
00:35:17,080 --> 00:35:20,073
the blanket of sea ice
is beginning to break up.

354
00:35:24,800 --> 00:35:27,315
Icebergs are gigantic fragments
of ice

355
00:35:27,480 --> 00:35:31,394
that have broken away into the sea
from the front of glaciers.

356
00:35:31,560 --> 00:35:34,951
During the winter,
they were frozen into the sea ice,

357
00:35:35,120 --> 00:35:37,396
but now they're set adrift
once more.

358
00:36:15,360 --> 00:36:17,033
As the bergs break up,

359
00:36:17,200 --> 00:36:19,112
they form brash ice.

360
00:36:20,080 --> 00:36:23,630
It litters the backwaters
of the Antarctic peninsula.

361
00:36:42,920 --> 00:36:47,312
Minke whales make their way
into these placid waters in summer.

362
00:36:47,480 --> 00:36:51,076
This is the most abundant whale
in the Southern Ocean.

363
00:37:02,280 --> 00:37:06,160
Minkes are one of the smallest
of all the baleen whales,

364
00:37:06,320 --> 00:37:09,233
and like all others,
they come here to feed.

365
00:37:22,120 --> 00:37:24,112
The majestic humpback whales

366
00:37:24,280 --> 00:37:26,078
are also summer visitors.

367
00:37:34,760 --> 00:37:37,195
They have travelled
thousands of miles

368
00:37:37,360 --> 00:37:40,592
from their winter breeding grounds
in the tropics

369
00:37:40,760 --> 00:37:44,436
to gather the food that becomes
available here in summer.

370
00:37:59,600 --> 00:38:01,193
In just four months,

371
00:38:01,360 --> 00:38:03,352
they accumulate enough fat

372
00:38:03,520 --> 00:38:07,480
to provide them with energy for
the whole of the rest of the year.

373
00:38:25,000 --> 00:38:28,550
All these animals have come here
in search of one thing —

374
00:38:28,720 --> 00:38:30,200
the krill.

375
00:38:31,360 --> 00:38:33,352
Krill is the mainstay

376
00:38:33,520 --> 00:38:35,512
of the Antarctic food web.

377
00:38:43,440 --> 00:38:45,636
It occurs in phenomenal quantity —

378
00:38:45,800 --> 00:38:48,634
billions of individuals
in a single swarm,

379
00:38:49,160 --> 00:38:51,391
and swarms can stretch for miles.

380
00:38:56,480 --> 00:39:00,713
Fur seals also collect
this rich, super—abundant food.

381
00:39:01,720 --> 00:39:03,712
Krill swarms are very patchy,

382
00:39:03,880 --> 00:39:05,360
but once found,

383
00:39:05,520 --> 00:39:07,000
feeding is easy.

384
00:39:33,280 --> 00:39:37,194
Humpbacks engulf
hundreds of thousands of them

385
00:39:37,360 --> 00:39:39,829
in a single gargantuan mouthful.

386
00:39:51,320 --> 00:39:52,800
When the going is good,

387
00:39:52,960 --> 00:39:54,838
the whales feed continuously,

388
00:39:55,000 --> 00:39:57,390
each eating
up to two tonnes of krill

389
00:39:57,560 --> 00:39:59,119
in 24 hours.

390
00:40:03,280 --> 00:40:06,796
Further south, near the continent,
the sea ice is still sound.

391
00:40:06,960 --> 00:40:10,192
Here, where the ice remains
for most of the summer,

392
00:40:10,360 --> 00:40:12,591
Emperor penguins make their home.

393
00:40:13,720 --> 00:40:16,189
These have been feeding out at sea,

394
00:40:16,360 --> 00:40:19,671
and are now ready to make
their way back to the colony

395
00:40:19,840 --> 00:40:21,479
to feed their chicks.

396
00:40:23,640 --> 00:40:27,156
Instead of heading
straight for the ice edge,

397
00:40:27,320 --> 00:40:30,233
the penguins hesitate
some distance from it.

398
00:40:31,080 --> 00:40:32,560
They're nervous.

399
00:40:44,600 --> 00:40:46,114
They dive down

400
00:40:46,280 --> 00:40:48,795
and investigate the ice edge...

401
00:41:03,320 --> 00:41:04,993
And for good reason.

402
00:41:05,160 --> 00:41:08,039
Leopard seals patrol this border.

403
00:41:16,120 --> 00:41:20,558
Leopard seals are the Antarctic's
equivalent of polar bears.

404
00:41:20,720 --> 00:41:22,518
They're the top predators,

405
00:41:22,680 --> 00:41:25,593
but they hunt most successfully
in the water,

406
00:41:25,760 --> 00:41:27,274
so by and large,

407
00:41:27,440 --> 00:41:30,512
the animals they prey on
are safer out on the ice.

408
00:41:37,320 --> 00:41:41,837
They have a lazy grace
that belies their ferocious nature.

409
00:41:56,000 --> 00:41:58,231
Confident that the coast is clear,

410
00:41:58,400 --> 00:42:00,995
the Emperor penguins
head for the ice...

411
00:42:03,000 --> 00:42:05,151
but they certainly don't linger.

412
00:42:45,400 --> 00:42:49,440
Now they have a long walk back
to the colony.

413
00:42:54,320 --> 00:42:58,234
Emperor penguin colonies are
some way back from the ice edge.

414
00:42:59,080 --> 00:43:02,551
In winter, they may be
as much as 100 miles from it,

415
00:43:02,720 --> 00:43:05,713
but as the summer progresses
and the ice melts,

416
00:43:05,880 --> 00:43:08,475
the edge comes ever closer
to the colony.

417
00:43:08,640 --> 00:43:11,109
So by the time the chicks
are fledged

418
00:43:11,280 --> 00:43:13,511
and ready to take their first swim,

419
00:43:13,680 --> 00:43:15,160
the water is close by.

420
00:43:23,160 --> 00:43:26,119
This colony is in the lee
of a headland,

421
00:43:26,280 --> 00:43:29,193
and that prevents the ice
from being broken up

422
00:43:29,360 --> 00:43:30,919
by ocean currents.

423
00:43:31,400 --> 00:43:33,960
The returning adults
are so full of food

424
00:43:34,120 --> 00:43:35,839
that they can barely walk,

425
00:43:36,000 --> 00:43:38,720
but with no predator
to threaten them now,

426
00:43:38,880 --> 00:43:40,872
they can take their time.

427
00:43:49,800 --> 00:43:53,680
Somehow, in this mêlée
of 60,000 or so penguins,

428
00:43:53,840 --> 00:43:56,036
a parent has to find its chick.

429
00:44:06,040 --> 00:44:09,317
It returns to the place
where it last left its chick

430
00:44:09,480 --> 00:44:12,359
in the hope
that it might still be close by...

431
00:44:14,800 --> 00:44:17,315
but chicks tend to wander,

432
00:44:17,480 --> 00:44:19,915
so the adult has to call to it.

433
00:44:22,400 --> 00:44:24,915
(ADULT MAKES LOW TRILLING CALL)

434
00:44:28,080 --> 00:44:30,231
(CHICK MAKES HIGH—PITCHED PEEP)

435
00:44:34,200 --> 00:44:35,714
The chick responds,

436
00:44:35,880 --> 00:44:38,190
and they slowly
home in on one another.

437
00:44:38,360 --> 00:44:40,750
The plaintive entreaties
of the chick

438
00:44:40,920 --> 00:44:44,596
stimulates the adult
to regurgitate a mouthful of fish.

439
00:44:55,160 --> 00:44:57,152
With the return of one parent,

440
00:44:57,320 --> 00:45:00,233
the other is free to go to sea
to feed for itself.

441
00:45:15,440 --> 00:45:17,830
Aware of the leopard seal's
presence,

442
00:45:18,000 --> 00:45:21,072
the penguins press together
at the ice edge

443
00:45:21,240 --> 00:45:24,358
unwilling to be the first
to risk diving in.

444
00:45:40,000 --> 00:45:43,038
Occasionally,
the seal comes out onto the ice

445
00:45:43,200 --> 00:45:45,192
and attempts to grab one...

446
00:46:00,000 --> 00:46:03,072
But its most successful strategy
by far

447
00:46:03,240 --> 00:46:04,720
is to lie in wait.

448
00:46:12,200 --> 00:46:14,635
It hides behind a corner of ice.

449
00:46:17,600 --> 00:46:19,592
The Emperors gain confidence

450
00:46:19,760 --> 00:46:21,274
and make a dash for it.

451
00:46:33,080 --> 00:46:35,675
The first wave of penguins escape.

452
00:46:38,400 --> 00:46:40,790
Once in open water,
they will be safe.

453
00:46:45,760 --> 00:46:47,991
But the seal is alerted
by the noise,

454
00:46:48,160 --> 00:46:51,392
and through the mass of bubbles,
it makes its attack.

455
00:47:02,000 --> 00:47:04,834
Almost invariably, it makes a kill.

456
00:47:12,160 --> 00:47:14,595
Encouraged by the absence
of the seal,

457
00:47:14,760 --> 00:47:18,231
the remaining penguins
make a break for the open sea.

458
00:47:37,640 --> 00:47:39,916
In time, their chicks will fledge,

459
00:47:40,080 --> 00:47:42,993
and when the Antarctic autumn
is near its end,

460
00:47:43,160 --> 00:47:46,392
these adults will walk
across the newly—formed ice

461
00:47:46,560 --> 00:47:48,552
to endure yet another winter

462
00:47:48,720 --> 00:47:50,951
on the frozen sea.