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00:28Transcription by CastingWords
00:44The Frozen Seas are worlds unto themselves.
00:49Beneath their ceiling of ice, they have an eerie, almost magical stillness, cut off from the storms that rage above.
01:01In the winter, the feeble slanting rays of the sun bring little warmth, and the temperature seldom rises above minus
01:0850 degrees centigrade.
01:23For much of the year, it is dark and cripplingly cold.
01:27Yet there is life here, at both ends of the Earth, the Arctic and the Antarctic.
01:44For most animals, whether they live in or out of water, the winters, when much of the sea is frozen,
01:51bring the greatest challenge.
01:57The Northern Hemisphere. It's February, and as the Earth tilts on its axis, the sun's rays creep slowly northwards, and
02:05the Arctic emerges from its harsh winter.
02:11The Arctic is a frozen ocean, surrounded by continents, and when the surface of the sea between the continents freezes
02:19from shore to shore, land predators walk out onto it to hunt.
02:31It's early March, and the sea is still covered with ice, but there are patches of open water, polinias, that
02:40never freeze over.
02:41Here, where tidal currents are squeezed between islands, the water movement is so strong that ice cannot form.
02:54Walruses spend the winter in polinias.
02:58Here, they have permanent access to the air, but they can also retreat to the sea to shelter or to
03:04hunt.
03:18Other sea mammals overwinter in polinias, as well. In this one, a young bowhead whale.
03:33Here, the current is really fast, and the shifting ice is dangerous.
03:43This whale became trapped when ice encircled it last autumn.
03:56There is no food here, but a whale must breathe, and the only place that it can do so for
04:02miles around is in this tiny hole.
04:07It's living entirely on its reserves of fat, but now they're dangerously low.
04:13It will be some months yet before it can escape.
04:31Elsewhere, other whales have also been trapped.
04:34These are belugas.
04:36Their tiny hole in the ice has been kept open, not by currents, but by the belugas' continuous movements as
04:43they rise to breathe.
04:50Open water is now some 20 miles away.
04:53It will be two months yet before the ice melts.
05:08The belugas are extremely thin, and most of them are horribly scarred.
05:22But their wounds were not inflicted by the ice.
05:34A whale would be a huge prize for any meat-eating hunter, and these belugas, trapped by the ice, are
05:41within reach of polar bears.
05:57When aware of the danger, the belugas stay submerged as long as they can.
06:02But they can only hold their breath for about 20 minutes.
06:24Catching a four-metre-long whale that weighs one tonne is no easy task.
06:29Even if that whale is weakened by starvation.
06:45But a beluga is well worth waiting for.
07:11Day by day, as the hole gets bigger, it becomes increasingly difficult for the bear to land a whale.
07:21Keeping its fur in good condition and free from salt is important for warmth, and the bear uses snow like
07:29blotting paper.
07:41These belugas have been attacked by many bears over the last six months, and some have been caught.
07:51It may have taken a long time and a lot of patience, but a catch, when it's made, brings abundant
07:57rewards of energy-rich blubber.
08:11Gulls rely on bear kills at this time of the year, and the colour of blood staining the ice attracts
08:17them from a long way away.
08:23The remaining belugas still have a long wait before they're released from their prison and the threat of slaughter.
08:38The remains of a bear's
08:59Peek foxes also rely on the polar bears to hunt on their behalf.
09:04They're the jackals of the north and scavenge from bear kills whenever they can.
09:17In winter and early spring, they're wholly dependent on bears.
09:22Only in the summer, when the sea ice melts, will they regularly catch prey for themselves.
09:35They're not strong enough to tackle adult seals, but can certainly take newborn pups or birds.
09:55This canny individual is going to bury its prize. It may need it during the uncertain times ahead.
10:06The presence of bears affects the behaviour of almost all the animals here, big and small.
10:13The bears tend to avoid the fringe of fragmented ice bordering open water, where travelling can be very laborious.
10:20But that very fact makes this area, the pack ice, a particularly good place for seals to pup.
10:36Harp seals breed here. Their pups are born with white coats, which camouflage them very effectively against the snow.
10:46Harp seals have a very short nursing period, a necessity on this unstable pack ice.
10:52But suckling is intensive. The pup feeds for just 12 days on milk that is 45% fat.
11:00Then it's abandoned and has to fend for itself.
11:07A male hooded seal.
11:14This impressive nasal display is used to warn away other males.
11:25And to win a mate.
11:28Wooded seals also breed on pack ice.
11:31Their pups suckle for only four days, the shortest nursing period known for any mammal.
11:37And all because the threat of polar bears caused them to breed on the unstable ice.
11:58Another arctic seal opts for the solid ice further north.
12:03Because it's easy for bears to hunt here, these ringed seals must be particularly vigilant and have to hide their
12:11pups.
12:16Ringed seals are comparatively small, so they can give birth to their pups in little caves or lairs under the
12:22snow.
12:24Here, a pup is out of sight and protected from bad weather.
12:32In late March and into April, female bears emerge from winter dens with their new cubs.
12:40The mother has not eaten for at least five months.
12:43And she's hungry.
12:45Very hungry.
12:54If she doesn't succeed in catching a regular supply of seals, her milk will fail and her cub will die.
13:06Beers have an extraordinarily sensitive sense of smell and can detect seal pups hidden in the snow from two kilometers
13:15away.
13:28But a female ringed seal uses several layers, and a bear will almost certainly have to break into a number
13:34before it finds one that is occupied.
13:45This is a crucial time for the cub.
13:48By watching its mother hunt, and by copying her actions, it's beginning to acquire the rudiments of its own hunting
13:55skills.
14:01Play is also important for developing muscles and improving coordination.
14:25As the days go by, the sun rises higher and remains above the horizon even at night.
14:40The female bear continues to hunt until her cub is too tired and can't keep up.
14:51She's smelt something.
15:17The pup escapes through a hole in its lair that leads to the sea below.
15:45Only one in twenty hunts is successful, but this mother must find a seal pup soon if her cub is
15:51dead.
15:51Her job is not to starve to death.
16:09As spring turns into summer, the sun's heat begins to melt the sea ice.
16:18Now the ocean is accessible, and the Arctic's summer visitors return.
16:24Migrating birds arrive from the south to nest and feed on the seafood that's now within their reach.
16:32Brunix Guillemots are the northern equivalent of penguins, but they have retained the power of flight,
16:38for they need to reach cliff ledges where their nests will be safe from predatory bears and foxes.
17:01Nonetheless, they are as at home in the water as in the air.
17:07They dive down to a depth of fifty meters or more to catch fish.
17:20In June, the ice begins to fracture.
17:24The cracks, or leads, form useful corridors of open water for air-breathing animals.
17:34Belugas migrating to their feeding grounds use these leads to penetrate the ice-covered seas
17:40and reach areas where their preferred food, Arctic cod, has spent the winter.
17:52The males regularly dive to about five hundred meters to find fish.
17:57The females and young, which have smaller lungs, only go to about three hundred and fifty.
18:15In late June and July, narwhals arrive.
18:20The females, who usually lack tusks, come first with their new calves.
18:25The males follow a little later.
18:41They also move up the leads in search of fresh feeding grounds.
18:58Bowheads, up to eighteen meters long and weighing a hundred tons.
19:02These are the only large whales that stay in the Arctic all year round.
19:23They are not after fish. They are seeking smaller prey.
19:29Despite having the largest mouths in the animal kingdom, the size of a small garage,
19:35they eat tiny crustaceans, copepods, straining them from the water
19:40with the four-meter-long strips of baleen that hang from their upper jaws.
19:54In the summer, they store enough energy to last them through the following winter,
19:58when food will be less abundant.
20:03As the ice melts away, the polar bears are forced to head for land.
20:10They are excellent swimmers and can cover a hundred miles of continuous open water if need be.
20:37They are excellent.
20:52Off East Greenland, there is little ice left by August,
20:56so walruses haul out to rest on land.
21:00At this time of the year, they are molting,
21:03getting rid of their old scarred and parasite-ridden skin.
21:16A bathe in the cold water brings some relief from the itching.
21:39But even there, the odd scratch is irresistible.
21:48But even there, the odd scratch is irresistible.
22:02They make daily excursions out to deeper water.
22:16Down at 20 meters, they root around in the sediment,
22:20using their sensitive bristles to search out soft-shelled clams.
22:43Once they find a clam, they suck its flesh from the shell with their powerful muscular mouths.
22:54Walruses can feed for about five minutes at this depth,
22:57before they have to return to the surface to breathe.
23:08elsewhere in the Arctic, belugas are gathering in their thousands.
23:12They congregate in just a few large estuaries.
23:18Belugas of all ages and sizes come here.
23:22There are even young calves.
23:36Some are so young, born only a week or so ago, that they need help.
23:41They swim on their mother's backs so that they can breathe more easily.
23:56As the tide moves up the estuary, the belugas follow,
24:00swimming into surprisingly shallow water.
24:11Like walruses, they also need to molt.
24:22A combination of warm fresh water and vigorous rubbing against the gravel does the trick.
24:40They remain here for days or even weeks.
24:43So it's likely that socializing is also important to them.
24:53After molting, they head back out to sea to feed.
25:03It's now autumn, and the sea begins to freeze over once again.
25:14Thin sheets of ice form at the surface and pile up layer upon layer,
25:18gradually creating an impenetrable barrier.
25:30By late November, the Arctic Ocean is sealed once again by ice.
25:49The lights of the aurora play in the winter sky.
26:03And at the other end of the planet, in the Antarctic,
26:07there is the southern aurora.
26:24Antarctica is now emerging from winter.
26:29This is the coldest, windiest place in the world.
26:32Temperatures are still hovering at a numbing minus 50,
26:36and the returning sun has virtually no warmth.
26:39Very few animals can survive such extreme conditions.
26:45But emperor penguins can.
26:54Standing on the frozen sea, they endure the full force of the Antarctic storms.
27:08Only by huddling together can they survive the appalling winter months.
27:20They take it in turns to bear the brunt of the gales.
27:26They can only live here at all, because Antarctica is surrounded by the great southern ocean,
27:32and no land predators have been able to reach it.
27:35So, unlike Arctic animals, they're not threatened by polar bears.
27:42The sea is still frozen.
27:45But one seal nonetheless manages to stay here, even throughout the winter.
27:54The Weddell seal.
28:11Underwater, it's protected from the storms above.
28:15But it must have access to the air all year in order to breathe.
28:31And they keep their breathing holes open with their teeth.
28:45Only by continually scraping away at the ice can they maintain access to the air.
28:51But that means that their teeth get badly worn down.
28:54Then they can no longer hunt and eat effectively.
28:59Weddell seals die young.
29:09The continent of Antarctica is so isolated and so high, almost 5,000 metres in places,
29:16that it's considerably colder than the Arctic.
29:23Ice slides slowly down from its centre towards its rim in immense glaciers.
29:31During winter, the continent effectively doubles in size as the sea freezes over.
29:37Ice forms around its shores and extends outwards for hundreds of miles around the entire land mass.
29:50Under the sea ice live small, shrimp-like creatures, krill.
29:54They have been here all winter.
29:59During these dark months, they feed by scraping algae from the ice.
30:07Remarkably, they also shrink in size and revert to their juvenile form to save energy.
30:20As the temperature rises in spring, the ice begins to melt and little air bubbles trapped within it are released.
30:29Microscopic algae grow around these bubbles and the krill now graze on them, gathering them up with their beating legs.
30:52As the sun's rays grow stronger and penetrate deeper into the water, floating algae begin to flourish.
31:00And krill leave the dwindling ice and gather in swarms as they harvest this new crop.
31:17Far to the north, beyond the blanket of sea ice, chinstrap penguins have been overwintering in the open ocean.
31:32The occasional iceberg gives them the chance of a rest, if they can get onto it.
31:42Far to the north.
31:43Far to the north.
31:45Far to the north.
31:46Far to the north.
31:48Far to the north.
31:50Far to the north.
31:52Far to the north.
31:53Far to the north.
31:54Far to the north.
31:55Far to the north.
31:57Far to the north.
31:58Far to the north.
31:59Far to the north.
32:07Far to the north.
32:08But this time of year, where they really want to be, is on land.
32:12It's just getting there that's tricky.
32:34It's spring, and the penguins are returning to breed.
32:44Their need to get ashore is now urgent and imperative.
33:00Doing so is all a matter of timing and picking the right ways.
33:07This is a Great Dower.
33:13No one has to wait for the dead in the bundles.
33:18No one has to wait for the moon.
33:19It's hard to wait.
33:35I don't think that it's going to wait until we leave.
33:52But their journey has only just begun.
33:56Most of them will have to walk many miles before they can find a nest site.
34:15This is Zavodovsky Island, which has the largest penguin colony in the world.
34:22About two million chinstraps breed here, and they come to this island for a good reason.
34:34It's an active volcano.
34:37The heat from the crater and the fumaroles keeps the slopes free from the ice and snow,
34:42allowing these chinstraps to start breeding earlier than those further south.
34:50But then again, living on an active volcano is not without its risks.
34:58Unlike the emperors, these penguins are able to lay their eggs on the bare ground.
35:03Little wonder so many of them choose to brave the mountainous waves in order to get here.
35:15Further south, near the continent, the blanket of sea ice is beginning to break up.
35:25Icebergs are gigantic fragments of ice that have broken away into the sea from the front of glaciers.
35:31During the winter, they were frozen into the sea ice.
35:34But now, they are set adrift once more.
35:50a strong woodинг here in the tcomp of the sea ice is the dark now.
35:54There we are not running around the sea ice.
35:57But now, the lake has been called
35:58The California city's Tree-River sealed this biennалось.
35:59A lucky one of our rivers is aboveetoforespotcly考ens and can't lie about that soldier-ideap from the island.
36:02Byron оказ 장ondale, the care of the coast, many of the Indiana city,...
36:15As the bergs break up, they form brash ice.
36:20It litters the backwaters of the Antarctic Peninsula.
36:43Minky whales make their way into these placid waters in summer.
36:48This is the most abundant whale in the Southern Ocean.
37:03Minkies are one of the smallest of all the baleen whales, and like all others, they come here to feed.
37:22The majestic humpback whales are also summer visitors.
37:36They have traveled thousands of miles from their winter breeding grounds in the tropics
37:41to gather the food that becomes available here in summer.
37:59In just four months, they accumulate enough water to feed.
38:03Enough fat to provide them with energy for the whole of the rest of the year.
38:25All these animals have come here in search of one thing.
38:29The krill.
38:31Krill is the mainstay of the Antarctic food web.
38:43It occurs in phenomenal quantity.
38:46Billions of individuals in a single swarm, and swarms can stretch for miles.
38:57Fur seals also collect this rich, super-abundant food.
39:02Krill swarms are very patchy, but once found, feeding is easy.
39:06phkeps have wyandreaks and the sea.
39:13The Willis of the Right Ocean
39:13Marjana, Ugh wow!
39:20His mother's mother looks very little through the sun, which would end the sea.
39:20All these tuvies were up to be on the sea.
39:22All these animals where he is in the sea.
39:27The sea of the sea is to the sea.
39:28In the sea of the sea.
39:31The sea of the sea.
39:34All these animals have been in the sea.
39:36The sea of the sea.
39:36and thousands of them in a single gargantuan mouthful.
39:52When the going is good, the whales feed continuously,
39:56each eating up to two tons of krill in 24 hours.
40:03Further south, near the continent, the sea ice is still sound.
40:08Here, where the ice remains for most of the summer,
40:11emperor penguins make their home.
40:15These have been feeding out at sea
40:17and are now ready to make their way back to the colony to feed their chicks.
40:25Instead of heading straight for the ice edge,
40:27the penguins hesitate some distance from it.
40:31They're nervous.
40:45They dive down and investigate the ice edge.
41:03And for good reason.
41:05Leopard seals patrol this border.
41:16Leopard seals are the Antarctic's equivalent of polar bears.
41:21They're the top predators.
41:23But they hunt most successfully in the water.
41:26So, by and large, the animals they prey on are safer out on the ice.
41:37They have a lazy grace that belies their ferocious nature.
41:57Confident that the coast is clear, the emperor penguins head for the ice.
42:01But they certainly don't linger.
42:28But they certainly don't linger.
42:46They have a long walk back to the colony.
42:55Now, they have a long walk back to the colony.
43:00In winter, they may be as much as 100 miles from it.
43:03But as the summer progresses and the ice melts,
43:06the edge comes ever closer to the colony.
43:09So, by the time the chicks are fledged and ready to take their first swim,
43:13the water is close by.
43:23This colony is in the lee of a headland.
43:26And that prevents the ice from being broken up by ocean currents.
43:32The returning adults are so full of food that they can barely walk.
43:37But with no predator to threaten them now, they can take their time.
43:50Somehow, in this melee of 60,000 or so penguins, a parent has to find its chick.
44:06It returns to the place where it last left its chick
44:09in the hope that it might still be close by.
44:15But chicks tend to wander.
44:18So the adult has to call to it.
44:34The chick responds and they slowly home in on one another.
44:38The plaintive entreaties of the chick stimulates the adult to regurgitate a mouthful of fish.
44:55With the return of one parent, the other is free to go to sea to feed for itself.
45:16Aware of the leopard seal's presence, the penguins press together at the ice edge, unwilling to be the first to
45:23risk diving in.
45:40Occasionally, the seal comes out onto the ice and attempts to grab one.
45:53Occasionally, the seal comes out onto the ice and attempts to grab one.
46:00But its most successful strategy by far is to lie in wait.
46:12It hides behind a corner of ice.
46:18The emperors gain confidence and make a dash for it.
46:33The first wave of penguins escape.
46:39Once in open water, they will be safe.
46:46But the seal is alerted by the noise and through the mass of bubbles, it makes its attack.
47:03Almost invariably, it makes a kill.
47:13Encouraged by the absence of the seal, the remaining penguins make a break for the open sea.
47:38In time, their chicks will fledge, and when the Antarctic autumn is near its end,
47:44these adults will walk across the newly formed ice to endure yet another winter on the frozen sea.
48:28If you wish to be found in the middle sea, theépendords are safe.
48:29The easement of the sea is taken over.
48:31Theacakland Proof is a 7-10-1991-hidee.
48:31The End of the Sea is a 7-10-2989-18ellow.
48:35The End of the Sea is a 7-10-2091-1611.
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