0:00:36 > 0:00:41Summer in the polar regions, and the sun never sets.
0:00:43 > 0:00:46Imagine a single day that lasts for months.
0:00:50 > 0:00:53Some polar animals will face great challenges
0:00:53 > 0:00:56as their ice world vanishes around them.
0:00:59 > 0:01:02Others must use this special time wisely,
0:01:02 > 0:01:05for summer's riches will not last.
0:01:33 > 0:01:35The summer is just beginning
0:01:35 > 0:01:38and the increasing power of the sun
0:01:38 > 0:01:41is creating a spectacular new landscape.
0:01:49 > 0:01:55This melting ice sheet in the Arctic is 150 miles long,
0:01:55 > 0:01:57with 1,000 waterfalls.
0:02:03 > 0:02:04Vast expanses of ice
0:02:04 > 0:02:09that were once stone still, have come to life.
0:02:34 > 0:02:37The polar bear's world is melting away
0:02:37 > 0:02:38under the constant summer sun.
0:02:48 > 0:02:53As the season advances, the frozen surface of the ocean disintegrates.
0:02:54 > 0:02:57Soon, the ice here will have totally vanished.
0:03:07 > 0:03:11The polar bear family have to adapt to their rapidly-changing home.
0:03:18 > 0:03:23For the two cubs, this is a whole new watery world.
0:03:23 > 0:03:26It's the first time they have seen the sea ice break up.
0:03:33 > 0:03:34They're only six months old
0:03:34 > 0:03:38and will be dependent on their mother for another two years.
0:03:43 > 0:03:45They have much to learn.
0:03:54 > 0:03:57Their first swimming lesson,
0:03:57 > 0:04:00and they're not sure that they want it.
0:04:11 > 0:04:15For their mother, swimming is second nature.
0:04:18 > 0:04:22But the cubs still prefer to have ice beneath their feet
0:04:22 > 0:04:23whenever they can.
0:04:35 > 0:04:38Soon, it will be impossible to avoid the water.
0:04:44 > 0:04:47This lone male has lived through a dozen summers
0:04:47 > 0:04:50and is perfectly at home in the sea.
0:04:56 > 0:04:59He can swim up to 50 miles a day.
0:05:01 > 0:05:06He's hungry, and he's searching this ice maze for seals.
0:05:16 > 0:05:20But travelling across this increasingly fragile ice scape
0:05:20 > 0:05:24is hard work for an animal weighing over half a tonne.
0:05:37 > 0:05:41It's also harder to hunt when you have to swim.
0:05:42 > 0:05:46In open water, the odds are in the seals' favour.
0:06:06 > 0:06:09Lean months lie ahead for the polar bears.
0:06:09 > 0:06:12They will have to adopt new hunting strategies,
0:06:12 > 0:06:14or risk starvation.
0:06:20 > 0:06:24The northern part of the Earth is now tilting towards the sun,
0:06:24 > 0:06:28and all around the Arctic, the sea ice continues its retreat.
0:06:38 > 0:06:41The last remnants of the ice world
0:06:41 > 0:06:44drift with the wind and the tides.
0:07:04 > 0:07:08The sun's heat may be gentle at these latitudes,
0:07:08 > 0:07:11but it is continuous for 24 hours a day,
0:07:11 > 0:07:15and it carves the ice into magical shapes.
0:07:30 > 0:07:36Those that need ice have to visit the glacier fronts to find it.
0:07:41 > 0:07:44A comfortable bed is hard to come by.
0:07:53 > 0:07:56A polar bear's fur is so dense
0:07:56 > 0:07:58that water is easily shaken off.
0:08:05 > 0:08:08And ice absorbs water like a towel.
0:08:30 > 0:08:32That's better.
0:08:35 > 0:08:38There's now little chance of catching seals,
0:08:38 > 0:08:42and this bear may not eat again until the end of summer.
0:08:46 > 0:08:49It's better to save energy and doze in the sun.
0:08:59 > 0:09:02The warmth of the sun's rays
0:09:02 > 0:09:05is now bringing the Arctic lands back to life.
0:09:24 > 0:09:26FAINT BIRDSONG
0:09:39 > 0:09:41TWITTERING
0:09:55 > 0:09:58BIRDSONG
0:10:04 > 0:10:06Red phalaropes.
0:10:06 > 0:10:09They've flown all the way from the tropics
0:10:09 > 0:10:12to feed in these rich Arctic waters.
0:10:12 > 0:10:15They stir up the tiny creatures
0:10:15 > 0:10:18that are now flourishing here with a special spinning dance.
0:10:25 > 0:10:29All excellent fuel as they hurry to rear the next generation.
0:10:32 > 0:10:37The Arctic terns have made an even longer journey to breed here.
0:10:37 > 0:10:42They have flown 11,000 miles from the Antarctic.
0:10:43 > 0:10:47Their newly-hatched chicks will need to grow fast
0:10:47 > 0:10:49if they're to accompany their parents
0:10:49 > 0:10:52when they return south in only six weeks' time.
0:10:56 > 0:11:00An eider duck has chosen to nest in the centre of the tern colony.
0:11:00 > 0:11:04Hardly a tranquil place to raise your young.
0:11:08 > 0:11:11But the noisy neighbours have a feisty attitude to life,
0:11:11 > 0:11:14and that can be very valuable.
0:11:14 > 0:11:17SQUAWKING
0:11:27 > 0:11:30A hungry bear looking for a meal
0:11:30 > 0:11:32can destroy hundreds of nests
0:11:32 > 0:11:33in a single raid.
0:11:33 > 0:11:35Defensive squadrons of terns
0:11:35 > 0:11:37take off immediately.
0:11:46 > 0:11:48Sharp beaks stab down from above.
0:11:48 > 0:11:52The bear has nothing in his armoury that can cope with this.
0:12:08 > 0:12:10The terns have drawn blood from his muzzle.
0:12:20 > 0:12:22He leaves in search
0:12:22 > 0:12:24of an easier meal.
0:12:28 > 0:12:32The eiders survive, thanks to their choice of neighbours.
0:12:39 > 0:12:42And the ducklings begin their sprint to maturity.
0:12:46 > 0:12:48Fishing continues around the clock
0:12:48 > 0:12:52as the terns race to rear their young
0:12:52 > 0:12:54before the return of the freeze.
0:13:04 > 0:13:09So the rich waters of summer fuel the breeding of all these visitors
0:13:09 > 0:13:12and enable them to build up the reserves they will need
0:13:12 > 0:13:14for the long return journey south.
0:13:27 > 0:13:30Inland, the winter snows have gone,
0:13:30 > 0:13:33revealing a vast treeless wilderness.
0:13:40 > 0:13:45The male snowy owl is finding plenty of lemmings
0:13:45 > 0:13:47to bring to his mate.
0:13:51 > 0:13:53But they're not just for her.
0:14:01 > 0:14:05She is brooding their rather scruffy young.
0:14:07 > 0:14:09She tears the meal into beak-sized chunks
0:14:09 > 0:14:12that the owlets can swallow whole.
0:14:12 > 0:14:14Each of them can eat two lemmings a day.
0:14:25 > 0:14:28The male has no time to rest.
0:14:28 > 0:14:32Over the course of the summer, he will have to provide his family
0:14:32 > 0:14:34with over 1,000 lemmings.
0:14:36 > 0:14:40The hungry owlets keep the adults working around the clock.
0:14:44 > 0:14:48The Arctic summer may be short, but the days are long.
0:14:49 > 0:14:54Everyone must take advantage of the 24-hour daylight.
0:14:54 > 0:14:59None more so than the owls' tiny neighbours, the Lapland buntings.
0:14:59 > 0:15:00SQUAWKING
0:15:13 > 0:15:17Both parents feed their growing family continuously.
0:15:28 > 0:15:31A mere ten days after hatching,
0:15:31 > 0:15:34and they will all have left in record time.
0:15:38 > 0:15:40The last needs a little encouragement.
0:15:49 > 0:15:52The owlets have also left their nest
0:15:52 > 0:15:55and turned into football-sized balls of fluff.
0:15:55 > 0:16:00But they still depend on their parents for food and protection.
0:16:06 > 0:16:08A skua.
0:16:08 > 0:16:10Their mother's talons are her best weapons.
0:16:34 > 0:16:38The owlets are dangerously exposed out on the tundra,
0:16:38 > 0:16:41so they must hurry to change from balls of fluff
0:16:41 > 0:16:43to fully-feathered adults.
0:16:43 > 0:16:47And to do that, they need...more lemmings.
0:16:56 > 0:16:59A lemming doesn't last long these days.
0:17:09 > 0:17:13Times are harder for the wolves here in the high Arctic.
0:17:28 > 0:17:33The cubs are now six weeks old and increasingly hungry.
0:17:45 > 0:17:49The adults have to struggle to feed their growing family.
0:17:55 > 0:17:58Somewhere on this vast expanse of tundra,
0:17:58 > 0:18:00there must be larger prey.
0:18:12 > 0:18:15Musk oxen are on the move.
0:18:22 > 0:18:24They're heading into the valleys,
0:18:24 > 0:18:28where the brief summer rains will produce fresh grazing.
0:18:39 > 0:18:42This is an opportunity that must be seized,
0:18:42 > 0:18:45even if it means travelling 80 miles in a day.
0:18:55 > 0:18:57Their task is a formidable one.
0:19:00 > 0:19:02Musk oxen are immensely powerful
0:19:02 > 0:19:05and their sharp horns can kill.
0:19:15 > 0:19:19A heavily-armoured bull would be an unwise choice.
0:19:19 > 0:19:23Even two wolves would find it a struggle to bring it down.
0:19:30 > 0:19:32A calf.
0:19:34 > 0:19:35Much easier.
0:19:56 > 0:19:58The two wolves work together
0:19:58 > 0:20:01to split the herd and isolate their victim.
0:20:22 > 0:20:25It seems that the wolf cubs will at last eat well.
0:20:30 > 0:20:32But the herd regroups.
0:20:41 > 0:20:43The cavalry ride to the rescue.
0:20:49 > 0:20:54The whole herd encircles the calf with a protective wall of horns.
0:20:59 > 0:21:03For the musk oxen, it's all for one and one for all.
0:21:17 > 0:21:19For the wolves, another attack
0:21:19 > 0:21:22would be not only futile, but dangerous.
0:21:25 > 0:21:27They have spent a lot of energy
0:21:27 > 0:21:30and have nothing whatever to show for it.
0:21:35 > 0:21:37FORLORN HOWL
0:21:45 > 0:21:49Their failure will be felt most keenly back at the den.
0:21:49 > 0:21:51HOWLING
0:22:01 > 0:22:06They have nothing to take back to the family.
0:22:11 > 0:22:13HOWLING
0:22:26 > 0:22:30The pack are forced to move on in search of better hunting.
0:22:36 > 0:22:38They must find something soon
0:22:38 > 0:22:40in this vast wilderness
0:22:40 > 0:22:42to feed their growing family.
0:22:44 > 0:22:47The brief Arctic summer is almost over.
0:22:57 > 0:22:59FAINT SQUAWKING
0:23:07 > 0:23:09At the southern end of the planet,
0:23:09 > 0:23:13the long summer days transform life,
0:23:13 > 0:23:17just as they do in the north, but the cast here is very different.
0:23:25 > 0:23:27King penguins.
0:23:28 > 0:23:34A parent, returning with food, must recognise its chick's call
0:23:34 > 0:23:37amongst a chorus of 400,000 birds.
0:23:59 > 0:24:02Huge colonies like this one
0:24:02 > 0:24:06are found all along the north coast of South Georgia.
0:24:10 > 0:24:14King penguins are active throughout the long summer days,
0:24:14 > 0:24:18so they have to deal with an uncharacteristic polar problem.
0:24:27 > 0:24:30By midday, the temperature can reach
0:24:30 > 0:24:33a sizzling 17 degrees centigrade.
0:24:37 > 0:24:41Any effort can lead to overheating.
0:24:41 > 0:24:44It's best not to overexert oneself.
0:24:47 > 0:24:51The heavily-insulated penguins stretch out
0:24:51 > 0:24:53so their naked feet can cool in the breeze.
0:25:06 > 0:25:09Their gigantic neighbours use a different approach.
0:25:09 > 0:25:14Wet sand cools the backs of these elephant seals,
0:25:14 > 0:25:16and also acts as a sunscreen.
0:25:25 > 0:25:30The chicks, in their downy coats that have kept them warm all winter,
0:25:30 > 0:25:33are in even greater danger of overheating.
0:25:50 > 0:25:53It will be two months before they can swim properly,
0:25:53 > 0:25:56but a dip in a shallow river brings a little relief.
0:26:14 > 0:26:19There is, however, another way to cool the blood.
0:26:22 > 0:26:27This murky pool has become a penguin spa.
0:26:34 > 0:26:37It's a great way to cool the feet,
0:26:37 > 0:26:39but there is no reason to stop there.
0:26:39 > 0:26:43You can indulge yourself with the full treatment.
0:26:58 > 0:27:00Mud, glorious mud!
0:27:14 > 0:27:17For the fully-feathered adults,
0:27:17 > 0:27:20there's a cleaner, more invigorating option.
0:27:25 > 0:27:28The bracing waters of the Southern Ocean.
0:28:31 > 0:28:35The 100-mile-long island of South Georgia
0:28:35 > 0:28:38lies on the northern fringe of Antarctica.
0:28:46 > 0:28:50Ice-free all year, its rich coastal waters
0:28:50 > 0:28:54make it a popular breeding destination for all beach lovers.
0:29:03 > 0:29:07In summer, 95% of the world's population
0:29:07 > 0:29:10of Antarctic fur seals come here.
0:29:12 > 0:29:14Packed tightly together, they form
0:29:14 > 0:29:17one of the densest gatherings of marine mammals on Earth.
0:29:21 > 0:29:24The island's beaches are filling fast
0:29:24 > 0:29:28and will soon be crammed with five million of these summer visitors.
0:29:31 > 0:29:36Space is at a premium, as every female needs a dry patch of sand
0:29:36 > 0:29:39the size of a beach towel for herself.
0:29:46 > 0:29:48And for good reason.
0:29:54 > 0:29:59Virtually all of them give birth within just ten days.
0:30:12 > 0:30:16It's crucial to establish a strong bond with your baby
0:30:16 > 0:30:19in such a crowded colony.
0:30:27 > 0:30:31The pups grow quickly on rich, high-fat milk.
0:30:41 > 0:30:45After giving birth, the females are ready to mate,
0:30:45 > 0:30:47so each male guards up to 15 of them
0:30:47 > 0:30:50in his small patch of beach.
0:30:50 > 0:30:55'A bull may only hold a territory for one season in his entire life.
0:30:56 > 0:31:01So when a challenger arrives, he will risk everything to retain it.
0:31:34 > 0:31:37Their sharp teeth inflict terrible injuries.
0:31:53 > 0:31:57Many bulls die from exhaustion after these fights.
0:32:01 > 0:32:06In the heat of the battle, the pups are also in real danger.
0:32:23 > 0:32:26The defeated bull makes his escape,
0:32:26 > 0:32:30but the colony still suffers from the side-effects of the battle.
0:32:38 > 0:32:43Many of the pups get lost in the violence and confusion.
0:32:43 > 0:32:45FORLORN BARKING
0:33:20 > 0:33:23This time, there is a happy ending.
0:33:32 > 0:33:34As summer progresses,
0:33:34 > 0:33:37even more of the Southern Ocean is gradually opening up.
0:33:45 > 0:33:48The summer melt, as it moves south,
0:33:48 > 0:33:51arrives first at the Antarctic Peninsula,
0:33:51 > 0:33:54the most northern tip of the continent.
0:33:57 > 0:34:02As the ice retreats, a dramatic 500-mile-long coastline
0:34:02 > 0:34:06is revealed for the first time in seven months.
0:34:13 > 0:34:15This new seascape is home
0:34:15 > 0:34:19to one of the most numerous mammals on the planet.
0:34:21 > 0:34:23Crabeater seals.
0:34:23 > 0:34:27Over 15 million live here, amongst the drifting ice floes.
0:34:38 > 0:34:42They owe their existence here to living organisms so small,
0:34:42 > 0:34:44you might hardly notice them.
0:34:47 > 0:34:51The underside of the sea ice is stained by algae.
0:34:52 > 0:34:55These microscopic plants
0:34:55 > 0:34:59support the most important Antarctic creatures of all.
0:35:00 > 0:35:03Krill.
0:35:03 > 0:35:07They have been grazing on the algal layer throughout the winter.
0:35:09 > 0:35:14As the ice melts, more of the algae are released into the water.
0:35:17 > 0:35:20Both algae and krill flourish in the summer sun.
0:35:26 > 0:35:31The krill collect the algae in the sieve-like basket
0:35:31 > 0:35:34formed by the interlocking hairs between their front legs.
0:35:42 > 0:35:48There are 300-million tonnes of krill in the Southern Ocean,
0:35:48 > 0:35:51with a greater combined weight
0:35:51 > 0:35:54than that of any other animal on the planet.
0:35:59 > 0:36:03Almost all the animals of the Antarctic depend on krill,
0:36:03 > 0:36:06including its giants.
0:36:08 > 0:36:09Humpback whales.
0:36:20 > 0:36:23They drive the krill to the surface
0:36:23 > 0:36:25and then strain it from the water
0:36:25 > 0:36:28with the baleen sieves in their mouths.
0:36:45 > 0:36:47Humpbacks often feed in teams,
0:36:47 > 0:36:50so the overspill from one huge mouth
0:36:50 > 0:36:53can be collected by another just behind.
0:37:28 > 0:37:32The abundance of krill attracts other visitors
0:37:32 > 0:37:34to the peninsula in the summer.
0:37:36 > 0:37:39Antarctic minke whales.
0:37:39 > 0:37:42Their pointed heads and short dorsal fins
0:37:42 > 0:37:45give them speed and endurance.
0:37:52 > 0:37:54And they need both.
0:38:02 > 0:38:04There are other whales here, too.
0:38:07 > 0:38:08Killers.
0:38:15 > 0:38:18This is an extended family of mothers and their young.
0:38:21 > 0:38:24And a male with a huge dorsal fin
0:38:24 > 0:38:27almost two metres high.
0:38:38 > 0:38:40A lone minke whale.
0:38:46 > 0:38:49It's just what this group of killer whales are looking for.
0:38:53 > 0:38:56Working as a team, as they have done for decades,
0:38:56 > 0:39:00they fan out across the strait in search of their quarry.
0:39:11 > 0:39:12And they've found it!
0:39:12 > 0:39:17The minke races away, pursued by outriders on each flank.
0:39:46 > 0:39:48Terrified, the minke heads for the shore.
0:39:51 > 0:39:54It's so desperate to escape, it almost beaches itself.
0:40:05 > 0:40:08It makes a desperate break for freedom.
0:40:17 > 0:40:19Two hours and 20 miles later,
0:40:19 > 0:40:23the minke is still alive and swimming strongly.
0:40:25 > 0:40:28Its only real defence is its endurance.
0:40:28 > 0:40:30But the killers work as a team,
0:40:30 > 0:40:34with fresh ones replacing the outriders in relays.
0:40:46 > 0:40:51And as the minke tires, the battering and the biting begins.
0:41:05 > 0:41:08Seabirds are attracted by the smell of fresh blood
0:41:08 > 0:41:10rising from the water.
0:41:28 > 0:41:31The killers try to flip the minke over.
0:41:31 > 0:41:36If they can manage to keep its blowhole underwater, it will drown.
0:41:41 > 0:41:45One forces the minke's whole body down below the surface.
0:42:01 > 0:42:03And then, the final strike.
0:42:08 > 0:42:12The team drag the minke under for the last time.
0:42:12 > 0:42:14And the hunters, finally, can feed.
0:42:31 > 0:42:33As the summer advances,
0:42:33 > 0:42:36the most southerly stretches of the Antarctic Ocean
0:42:36 > 0:42:39are released from the ice.
0:42:48 > 0:42:52Adelie penguins have been feeding in the open ocean.
0:43:04 > 0:43:06The most southerly of all penguins,
0:43:06 > 0:43:09they're returning to the Antarctic continent
0:43:09 > 0:43:12with stomachs full of krill.
0:44:03 > 0:44:09The sea ice has finally retreated all the way back to the beach,
0:44:09 > 0:44:13so the walk back to the colony is as short as it will ever be.
0:44:13 > 0:44:16Crucial for the half-million penguins here
0:44:16 > 0:44:20who are hurrying to raise their chicks before the freeze returns.
0:44:24 > 0:44:28Most of the pairs have two chicks to care for.
0:44:30 > 0:44:34Each chick requires nearly 30 kilograms of food
0:44:34 > 0:44:35before it's fully grown.
0:44:39 > 0:44:42Most of their catch is krill,
0:44:42 > 0:44:44and Adelie penguins consume a staggering
0:44:44 > 0:44:481.5 million tonnes of it a year.
0:44:56 > 0:45:00'There are no land-based predators in Antarctica.
0:45:02 > 0:45:06The threat here comes from the skies.
0:45:17 > 0:45:18A South polar skua.
0:45:38 > 0:45:42An unguarded chick is an easy catch.
0:46:10 > 0:46:12Nothing can save the chick now.
0:46:30 > 0:46:35But now the parents can focus all their attention on the second.
0:46:55 > 0:47:00Only half of these chicks will survive to adulthood.
0:47:00 > 0:47:03But there are thousands more parents with young
0:47:03 > 0:47:05in this huge colony.
0:47:07 > 0:47:12Parents that cannot rest, for their young must be fit and strong
0:47:12 > 0:47:16if they're to survive the dangers that autumn will bring.
0:47:42 > 0:47:44Next time - Autumn.
0:47:44 > 0:47:47And the sun starts to set on the frozen planet.
0:47:49 > 0:47:54The race is on to finish breeding before the big freeze.
0:48:18 > 0:48:21In summer, the frozen oceans melt
0:48:21 > 0:48:25and the polar animals disperse to feed amongst the broken ice.
0:48:27 > 0:48:30So, even finding them in this vast expanse of sea
0:48:30 > 0:48:33and drifting ice floes wouldn't be easy.
0:48:38 > 0:48:43In the Arctic, the aim was to get close to a polar bear family
0:48:43 > 0:48:46and film them in this fast-melting world.
0:48:53 > 0:48:55Firstly, the team had to use
0:48:55 > 0:48:59a ship capable of breaking through the pack ice
0:48:59 > 0:49:03around the 2,000-mile-long coastline of Svalbard.
0:49:05 > 0:49:09Producer Miles Barton and cameraman Ted Giffords
0:49:09 > 0:49:14are checking out fjords known to be frequented by bears.
0:49:14 > 0:49:19We've just seen a bear walking around in front of a glacier over there.
0:49:19 > 0:49:21We've just arrived, so this is a test, more than anything,
0:49:21 > 0:49:25but we're going to go and see if we can film it.
0:49:25 > 0:49:28We're seeing how smoothly we can make this operation work.
0:49:35 > 0:49:39"Stay on Channel Six. Can you give me directions to the bear, please?"
0:49:41 > 0:49:45The plan is that the team's stabilised aerial camera,
0:49:45 > 0:49:47now fitted to the speedboat,
0:49:47 > 0:49:51will give perfectly stable shots of the bear swimming.
0:49:51 > 0:49:55- If we spin this around, we'll lose it.- The fellow's over here, yeah?
0:49:55 > 0:49:58- Oh, yeah, got him!- I can't get any tighter.- You shoot it?
0:50:02 > 0:50:03Whey!
0:50:06 > 0:50:09That's nice. Nice sparkle, nice liquid look.
0:50:09 > 0:50:12- Let's let him go.- OK. Cut.
0:50:15 > 0:50:20After their initial success, the weather takes a turn for the worse.
0:50:24 > 0:50:27For five days, there are no more polar bears.
0:50:30 > 0:50:33The captain decides to take a break
0:50:33 > 0:50:36and parks up in the pack ice.
0:50:39 > 0:50:43After all that fruitless searching by the crew, a bear visits them.
0:50:48 > 0:50:51A large and inquisitive adult male.
0:50:58 > 0:51:00So the team decides to follow him.
0:51:03 > 0:51:06The open water between boat and bear
0:51:06 > 0:51:08means the crew can safely film
0:51:08 > 0:51:12from surprisingly close range without disturbing him.
0:51:12 > 0:51:15That's nice. Oop!
0:51:18 > 0:51:20The bear is so relaxed,
0:51:20 > 0:51:23he even begins to hunt right alongside them.
0:51:23 > 0:51:27He's looking for a seal inside.
0:51:27 > 0:51:29But he's just completely ignoring us.
0:51:29 > 0:51:32Just hold it there. Just hold it there for a minute.
0:51:32 > 0:51:35- He's going to climb up.- OK.- Ready?
0:51:38 > 0:51:40Ha-ha! That's a big bear!
0:51:45 > 0:51:47That's pretty good, pretty good.
0:51:48 > 0:51:51The closest we've been to a polar bear so far.
0:51:53 > 0:51:55Despite this remarkably close encounter,
0:51:55 > 0:52:00the team still wants to film a family of bears.
0:52:00 > 0:52:04"There's these females and two cubs to the starboard side.
0:52:04 > 0:52:07- "She's at two..." - There's good news on the radio.
0:52:07 > 0:52:12Oh, there's a cub. Yeah, I've seen the cubs.
0:52:12 > 0:52:15They're looking straight at us. Look at that.
0:52:15 > 0:52:17That's amazing!
0:52:17 > 0:52:19As the mother looks distinctly hungry,
0:52:19 > 0:52:23they will need to keep at least 15 feet of open water
0:52:23 > 0:52:26between her and the boat.
0:52:26 > 0:52:28Having a good look at us.
0:52:28 > 0:52:32- Oh, look at them! Look at the cubs! - Yeah.- Ha-ha!
0:52:38 > 0:52:40Jason, just go when you need to.
0:52:42 > 0:52:45- Oop, here she comes.- Bloody hell!
0:52:47 > 0:52:50Mother bears are always desperate for food for their cubs,
0:52:50 > 0:52:54so the crew could be the perfect supper.
0:52:54 > 0:52:57- She's getting in.- Oh, my God, she's going to come in the water there.
0:52:59 > 0:53:01The 15-foot gap was just enough.
0:53:01 > 0:53:03God, that was amazing!
0:53:09 > 0:53:12- We have to go.- OK.
0:53:14 > 0:53:17- Do you want to get close up to the cubs?- Still rolling.
0:53:17 > 0:53:20Yeah, that's cute. She's going in the water. OK.
0:53:20 > 0:53:23And then I'm going to stay with the cubs.
0:53:23 > 0:53:26With the cubs for a nice splash.
0:53:29 > 0:53:33Go on, cubs. Yeah! Hey!
0:53:33 > 0:53:35Well done! Well done!
0:53:35 > 0:53:36Great stuff!
0:53:38 > 0:53:41She looked like she wanted to get in the boat.
0:53:43 > 0:53:46Sometimes, it's quite shocking to actually look up from the monitor
0:53:46 > 0:53:49and realise they're about 15 feet away from you.
0:53:49 > 0:53:51But, um, a lovely family group.
0:53:55 > 0:53:57The boat-based camera has helped
0:53:57 > 0:53:59to get remarkably close shots of the bear family,
0:53:59 > 0:54:02but how would it cope in the more extreme conditions
0:54:02 > 0:54:04of the Southern Ocean?
0:54:13 > 0:54:17Another Frozen Planet team headed south.
0:54:17 > 0:54:21The plan is to use the same camera system to film the hunting strategy
0:54:21 > 0:54:26of the most spectacular marine predators in Antarctica.
0:54:27 > 0:54:29Killer whales.
0:54:30 > 0:54:34The team enlisted the help of scientists Bob Pitman
0:54:34 > 0:54:36and John Durban.
0:54:36 > 0:54:38They had put satellite tags on the whales,
0:54:38 > 0:54:42and so could locate them for the camera team.
0:54:44 > 0:54:48Doug Allan operates the camera rig from the wheelhouse,
0:54:48 > 0:54:51while Doug Anderson films from the deck.'
0:54:51 > 0:54:53Yeah, there. See it?
0:54:53 > 0:54:56It just surfaced right with them.
0:54:56 > 0:54:58OK, there's a killer whale at 11:00,
0:54:58 > 0:55:02about 200 metres heading towards those two seals on the floe.
0:55:02 > 0:55:04Good. This could be really good.
0:55:05 > 0:55:08At last, having tracked the group for several days,
0:55:08 > 0:55:11the whales look as if they are about to hunt.
0:55:11 > 0:55:14Yeah, they're going to go in for it.
0:55:17 > 0:55:19There it goes.
0:55:22 > 0:55:26Four whales there. Um, two adult females,
0:55:26 > 0:55:28a juvenile and a big adult male.
0:55:28 > 0:55:31Swimming in formation, the killers create a wave
0:55:31 > 0:55:34to wash the seal off the floe.
0:55:34 > 0:55:36It's all pretty intense.
0:55:36 > 0:55:38Oh. There's another wave.
0:55:38 > 0:55:41- Yes.- Wave! Wow!
0:55:43 > 0:55:45Yeah, he's in the water.
0:55:45 > 0:55:47Having successfully filmed several hunts
0:55:47 > 0:55:49with the boat-based cameras from above,
0:55:49 > 0:55:53the team are keen to see what's happening underwater.
0:55:55 > 0:55:57Only one way to find out.
0:56:01 > 0:56:03Time to launch the dinghy.
0:56:11 > 0:56:13Doug Anderson approaches the seal and the killers
0:56:13 > 0:56:17with an underwater camera mounted on a pole.
0:56:25 > 0:56:28For the first time, the team can see
0:56:28 > 0:56:33- how the whales create the killer wave.- There it is.
0:56:36 > 0:56:38The underwater camera also reveals
0:56:38 > 0:56:42surprisingly cautious behaviour by the whales.
0:56:42 > 0:56:46They seem wary of being bitten by the much smaller seal.
0:56:48 > 0:56:51And they even blow bubbles to confuse it.
0:56:51 > 0:56:54They're so cautious with the seals.
0:56:54 > 0:56:57At the end of the day, the seal's got a big mouth full of teeth,
0:56:57 > 0:56:59and these whales just don't take risks.
0:57:08 > 0:57:10Having dealt with the seal,
0:57:10 > 0:57:13the whales turn their attention to the dinghy.
0:57:13 > 0:57:16First, they get right up close
0:57:16 > 0:57:19for a better look at Doug.
0:57:26 > 0:57:28Then they line up to create the kind of wave
0:57:28 > 0:57:30that washed the seal off the floe.
0:57:30 > 0:57:33Oooh!
0:57:34 > 0:57:37For a moment, the crew get an uncomfortably close
0:57:37 > 0:57:41seal's eye view of this remarkable hunting strategy.
0:57:46 > 0:57:51Look! See that? The juvies are making waves.
0:57:53 > 0:57:57It's a great feeling being there. Being so close to the behaviour,
0:57:57 > 0:57:59having the water coming into the boat.
0:57:59 > 0:58:01From our point of view, you know,
0:58:01 > 0:58:05it's all about trying to get the feeling of being with these whales.
0:58:05 > 0:58:08With these whales, there's no bother with that. They're so confident.
0:58:08 > 0:58:11They just want to be all around you and checking you out.
0:58:11 > 0:58:15I can't imagine I'll have another experience like this in my career.
0:58:15 > 0:58:18You know, these come along rarely.
0:58:18 > 0:58:22And you just feel happy and lucky when...when they do come.
0:58:22 > 0:58:25You just don't get better days than that.
0:58:32 > 0:58:34Subtitles by Red Bee Media Ltd
0:58:34 > 0:58:36E-mail subtitling@bbc.co.uk