Challenges of Life

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0:00:21 > 0:00:22Our planet may be home

0:00:22 > 0:00:26to 30 million different kinds of animals and plants.

0:00:26 > 0:00:31Each individual locked in its own life-long fight for survival.

0:00:32 > 0:00:36Everywhere you look, on land or in the ocean, there are extraordinary

0:00:36 > 0:00:40examples of the lengths living things go to to stay alive.

0:00:45 > 0:00:47This is the coast of Florida.

0:00:49 > 0:00:52Here, strange scars on the sea bed

0:00:52 > 0:00:55hint at one animal's remarkable strategy.

0:01:00 > 0:01:03These are bottlenose dolphins,

0:01:03 > 0:01:06one of the most intelligent animals on Earth.

0:01:07 > 0:01:12Their prey is very elusive, fast-swimming fish.

0:01:12 > 0:01:17But the dolphins have invented a completely new way of hunting.

0:01:20 > 0:01:25By beating its tail down hard, this dolphin stirs up the shallow silt.

0:01:32 > 0:01:35And by swimming in a tight circle

0:01:35 > 0:01:39it creates a ring of mushrooming mud around a shoal of fish.

0:01:59 > 0:02:03The contracting ring traps the fish just like a net.

0:02:03 > 0:02:06Panicked, the fish jump to escape.

0:02:08 > 0:02:11Right into the open mouths of the waiting dolphins.

0:02:24 > 0:02:27Again and again, the lead dolphin creates a circle,

0:02:27 > 0:02:30before they all line up with perfect timing.

0:02:57 > 0:03:04These dolphins are the only ones known to have developed this hunting behaviour and it gives them an edge.

0:03:08 > 0:03:13This sort of advantage may mean the difference between life and death

0:03:13 > 0:03:15in the survival of the fittest.

0:03:21 > 0:03:25This series reveals the most spectacular and extraordinary

0:03:25 > 0:03:30strategies that animals and plants have developed to stay alive.

0:04:06 > 0:04:09For every creature, every day is full of challenges,

0:04:09 > 0:04:14all of which must be overcome, somehow, in order to survive.

0:04:26 > 0:04:30Kenya, famous for its big cats.

0:04:30 > 0:04:32The supreme hunters.

0:04:44 > 0:04:48Cheetahs specialise in hunting at speed.

0:04:48 > 0:04:52Though fast, they are fragile creatures,

0:04:52 > 0:04:55built to sprint after small prey.

0:04:55 > 0:04:57They don't have the strength or weight of a lion

0:04:57 > 0:04:59to bring down larger animals.

0:05:02 > 0:05:04This male is different.

0:05:04 > 0:05:08He doesn't hunt alone. He's learnt that there is strength in numbers.

0:05:22 > 0:05:27But here there are not just two, but three cheetahs.

0:05:27 > 0:05:29A band of brothers.

0:05:36 > 0:05:40They have changed their tactics and, by doing so,

0:05:40 > 0:05:43have taken their prey by surprise.

0:05:43 > 0:05:46They have learnt that working together

0:05:46 > 0:05:49they can bring down large prey.

0:05:53 > 0:05:55An ostrich.

0:05:55 > 0:05:59A bird that towers over a cheetah and is more than twice as heavy.

0:06:01 > 0:06:05It can't fly to escape danger, but it can lash out with a deadly kick.

0:06:07 > 0:06:11A female, unaware as yet, of any danger.

0:06:17 > 0:06:20Even with three of them this is still highly risky.

0:06:20 > 0:06:26If one gets injured the other two couldn't hope to tackle such large prey.

0:06:34 > 0:06:38On the other hand, if they get it right, the rewards

0:06:38 > 0:06:40are huge.

0:06:47 > 0:06:52The male has spotted one of the brothers, but only one.

0:06:52 > 0:06:53It's not too worried.

0:07:06 > 0:07:08Then suddenly there are three!

0:07:20 > 0:07:22The female is slower to realise the danger

0:07:22 > 0:07:24and the cheetahs switch targets.

0:07:50 > 0:07:56It takes the combined effort and weight of all three brothers to bring down this powerful bird.

0:07:56 > 0:08:00Even now the ostrich could land a fatal kick.

0:08:08 > 0:08:10So far, the brothers are winning.

0:08:10 > 0:08:13Ostriches have yet to find a way to foil such tactics.

0:08:17 > 0:08:21Other animals have also evolved surprising tactics to outmanoeuvre

0:08:21 > 0:08:26the enemy, not with brute strength but with extraordinary weapons.

0:08:27 > 0:08:29Madagascar.

0:08:31 > 0:08:35A strange world where nothing is quite as it seems.

0:08:44 > 0:08:50To hunt here requires stealth and subterfuge.

0:08:50 > 0:08:55And living within the trees is a master of ambush.

0:08:55 > 0:08:57A preying mantis.

0:08:58 > 0:09:01Well camouflaged and lightning quick,

0:09:01 > 0:09:04these insects are highly efficient predators.

0:09:22 > 0:09:25But even they are outgunned.

0:09:32 > 0:09:35A chameleon.

0:09:35 > 0:09:41Its camouflage is exceptional because it can change its skin colour to match its surroundings.

0:09:49 > 0:09:53Its eyes move independently to spot prey.

0:09:57 > 0:10:01It creeps towards to its victim, until just in range.

0:10:06 > 0:10:09Then it unleashes a super weapon.

0:10:09 > 0:10:14Its tongue shoots out at 15 metres per second.

0:10:18 > 0:10:23And not only hits, but grasps its target.

0:10:39 > 0:10:42But few hunters are always successful.

0:10:42 > 0:10:45For them a hunt is just one meal.

0:10:45 > 0:10:47For prey, the stakes are higher.

0:10:47 > 0:10:50It's life...or death.

0:11:02 > 0:11:10As Antarctica moves from spring into summer, the inlets and bays, once choked with ice, become free.

0:11:15 > 0:11:17And animals move in to feed.

0:11:27 > 0:11:29These are crabeater seals.

0:11:29 > 0:11:36They don't actually eat crabs, but krill, small shrimps that swarm in their billions in these waters.

0:11:50 > 0:11:54Resting on a large ice floe, these crabeaters are safe.

0:12:04 > 0:12:10But as soon as they enter the water, they are on their guard,

0:12:10 > 0:12:11for good reason.

0:12:15 > 0:12:16Killer whales.

0:12:20 > 0:12:25Here in Antarctica, many killer whales prey only on fish.

0:12:25 > 0:12:30But these whales are different, they specialise in hunting seals.

0:12:43 > 0:12:50This seal swimming to open water is unaware of the danger heading his way.

0:12:52 > 0:12:54Until now.

0:12:59 > 0:13:06He's in real trouble. There is no escape unless he can hide behind this small piece of floating ice.

0:13:28 > 0:13:31But he's been spotted and surrounded.

0:13:45 > 0:13:47Now agility is his only chance.

0:13:47 > 0:13:51He dodges for his life, staying as close as he can to the iceberg.

0:14:03 > 0:14:04He's tiring.

0:14:05 > 0:14:08And the whales tighten the circle, going for the kill.

0:14:37 > 0:14:39But hunters don't always get their own way.

0:14:42 > 0:14:46In the end, the seal's determination and skill, using

0:14:46 > 0:14:50the ice for protection, kept him just out of reach.

0:14:54 > 0:14:57And the whales move on.

0:15:01 > 0:15:03Recently it's been observed that killer whales

0:15:03 > 0:15:07are much more successful when hunting other types of seal.

0:15:07 > 0:15:12Crabeaters like this put up too much of a fight.

0:15:26 > 0:15:31For creatures living in the open ocean there is nowhere to hide from predators.

0:15:31 > 0:15:34But there is safety in numbers.

0:15:59 > 0:16:03One fish, however, has evolved a different escape tactic.

0:16:07 > 0:16:11To leave the water completely, take to the air and fly!

0:16:18 > 0:16:22After a huge effort to get airborne, flying fish

0:16:22 > 0:16:26can glide 200 metres or so, to escape the predators chasing them.

0:17:11 > 0:17:16Not all animals are hunters, many are vegetarians.

0:17:16 > 0:17:21But the battle between animals and plants can also be intense.

0:17:24 > 0:17:27Boa Vista, central Brazil.

0:17:30 > 0:17:34This valley is peppered with strangely pitted rocks.

0:17:44 > 0:17:53These are not natural formations but the legacy of a long struggle between one animal and one plant.

0:17:55 > 0:18:00Brown-tufted capuchins, highly intelligent monkeys.

0:18:00 > 0:18:04They spend their nights in the safety of caves,

0:18:04 > 0:18:07emerging each morning to find food.

0:18:13 > 0:18:16Down in the valley is a particular favourite.

0:18:16 > 0:18:18A nut palm.

0:18:18 > 0:18:24The palms produce huge seeds, but they have very strong shells

0:18:24 > 0:18:27that protect them against attack from hungry animals.

0:18:34 > 0:18:39For the capuchins this is a war of attrition.

0:18:42 > 0:18:47They check which seed is the ripest, and the battle commences.

0:18:53 > 0:18:59The first job is to tear the tough fibrous husk from the nut.

0:19:03 > 0:19:07He doesn't try to crack the nut straight away,

0:19:07 > 0:19:09but drops it to the ground.

0:19:09 > 0:19:15He's learnt that a nut should be given a week or so drying in the sun.

0:19:15 > 0:19:17These are ones he prepared earlier.

0:19:17 > 0:19:20He taps them to see if they're ready.

0:19:32 > 0:19:36This huge flat rock is his anvil.

0:19:48 > 0:19:50And this is a hammer.

0:19:51 > 0:19:56It's made of a different and much harder rock than the anvil.

0:19:59 > 0:20:02Now something extraordinary happens.

0:20:15 > 0:20:20The capuchins' use of these stone tools requires an exceptional level

0:20:20 > 0:20:23of intelligence, planning and dexterity.

0:20:36 > 0:20:42The nut finally cracks and exposes a rich, oily kernel.

0:20:49 > 0:20:54Youngsters watch and imitate the adults, just as human toddlers do.

0:20:54 > 0:20:56If they are to become independent,

0:20:56 > 0:20:59they must learn to crack their own nuts.

0:21:05 > 0:21:10But the learning process is long, with many frustrations.

0:21:13 > 0:21:18They learn early on that to do a job properly,

0:21:18 > 0:21:20you need the right tool.

0:21:30 > 0:21:33It can take eight years for a capuchin to master this art

0:21:33 > 0:21:37and overcome the palm's formidable defences.

0:21:47 > 0:21:53But some plants have turned the tables and feed on animals.

0:21:57 > 0:22:02This is a highly sophisticated trap. The bait,

0:22:02 > 0:22:07sugary nectar around the rim of the disc.

0:22:07 > 0:22:15The triggers, fine hairs, two of which have to be touched within 20 seconds of each other.

0:22:23 > 0:22:29The victim, a fly which finds the colour and nectar irresistible.

0:22:38 > 0:22:39One.

0:22:52 > 0:22:53Two.

0:23:00 > 0:23:07When triggered, the trap snaps shut so fast that the fly is imprisoned.

0:23:16 > 0:23:20The Venus flytrap now slowly digests its victim.

0:23:36 > 0:23:40Life's challenges are more than just finding food.

0:23:40 > 0:23:45In every animal's life there comes a time when its mind turns to breeding.

0:23:47 > 0:23:50One creature's approach is mind-boggling.

0:23:54 > 0:23:56Malaysia.

0:24:10 > 0:24:15This strange insect has been lying dormant on the forest floor.

0:24:44 > 0:24:53Once safe in the trees, these males hide among the leaves and begin an extraordinary transformation.

0:24:54 > 0:24:59One that will make the difference between fathering offspring or not.

0:25:02 > 0:25:07He begins by gulping in air bubbles, forcing them up into his head.

0:25:09 > 0:25:13He then pumps the bubbles into the stalks supporting his eyes,

0:25:13 > 0:25:15just like blowing up a balloon.

0:25:22 > 0:25:26And this is what earns these creatures their name,

0:25:26 > 0:25:28the stalk-eyed fly.

0:25:44 > 0:25:49A few final adjustments to straighten out any remaining creases

0:25:49 > 0:25:51and he's ready for action.

0:25:56 > 0:26:02They may look unwieldy, but eyes on stalks improve not only his ability

0:26:02 > 0:26:07to spot predators, but they are key when it comes to winning females.

0:26:16 > 0:26:24In the evening both males and females gather and the males begin to size one another up, eyeball to eyeball.

0:26:24 > 0:26:30Having the widest eye span puts you at the top of the pecking order.

0:26:32 > 0:26:36The eye stalks are not weapons, they're measuring sticks,

0:26:36 > 0:26:41used to gauge how big, and so how strong, a male is.

0:26:41 > 0:26:45But there's trouble if two top males have exactly the same eye width.

0:26:45 > 0:26:50Then the contest descends into a brawl.

0:27:01 > 0:27:04Defeated.

0:27:04 > 0:27:09The winner. He now has the right to mate with all the females nearby.

0:27:16 > 0:27:23The rather gentlemanly way stalk-eyed flies settle their differences over females is not the only way.

0:27:23 > 0:27:25Some animals are much more violent.

0:27:25 > 0:27:29It's the dry season in Zambia.

0:27:30 > 0:27:39The lagoons are either baked dry, or the mud is so thick animals get stuck, with fatal consequences.

0:27:41 > 0:27:48This male hippo has been living in one small lagoon, but as it dries, it's turning into a death trap.

0:27:50 > 0:27:55Understandably, the females that once shared it with him have all left.

0:27:58 > 0:28:03Even if he wants to, he can't stay much longer.

0:28:03 > 0:28:07He needs water to keep cool and females to mate with.

0:28:12 > 0:28:14And this is where they all are.

0:28:14 > 0:28:19Almost all the hippos in the area are in what is left of the Luangwa River,

0:28:19 > 0:28:23because it's the last place where there's still deep water.

0:28:26 > 0:28:30This bend is controlled by an all-powerful male.

0:28:30 > 0:28:34Since the drought many more females have joined his herd.

0:28:37 > 0:28:42THEY BELLOW

0:28:44 > 0:28:48They are happy to live cheek by jowl, but any male who comes here

0:28:48 > 0:28:52in the hope of mating must first defeat the overlord.

0:29:02 > 0:29:09The wandering male arrives and has a decision to make - submit or fight.

0:30:19 > 0:30:22Victory for the overlord.

0:30:22 > 0:30:29His domination of his channel in the river remains and with it mating rights with the females.

0:30:36 > 0:30:40The loser is alive, but is an outcast.

0:30:40 > 0:30:46He retreats to another part of the river where it's so shallow that no females will follow.

0:30:48 > 0:30:53His chance to father offspring is over for now.

0:30:58 > 0:31:04For some animals the challenges of breeding are not about fighting but about courtship.

0:31:07 > 0:31:15Among birds, displays, songs and rituals can reach extraordinary levels of complexity and beauty.

0:31:22 > 0:31:26During spring, on the freshwater lakes of Oregon,

0:31:26 > 0:31:29grebes join together to renew their partnership.

0:31:44 > 0:31:48The ceremony starts with a series of graceful duets,

0:31:48 > 0:31:51in which one partner echoes the actions of the other.

0:31:58 > 0:32:01But the real test comes now.

0:32:01 > 0:32:05Only the strongest and the most faithful

0:32:05 > 0:32:09are prepared to join together for the final exultant dance.

0:33:03 > 0:33:08Those animals which have young now face a whole new set of challenges,

0:33:08 > 0:33:11to protect and nurture their offspring.

0:33:15 > 0:33:21In the cold waters of the northern Pacific Ocean, there lives a giant.

0:33:26 > 0:33:31A giant Pacific octopus at over four metres long.

0:33:35 > 0:33:40She is hunting, not for prey, but for a den.

0:33:40 > 0:33:42Somewhere to settle down and hide.

0:33:52 > 0:33:56Her den has to be just right.

0:33:56 > 0:34:00She's going to live here for the rest of her life.

0:34:03 > 0:34:06She's carrying fertilised eggs,

0:34:06 > 0:34:10and now, happy and settled, she lays them.

0:34:12 > 0:34:14100,000 of them.

0:34:20 > 0:34:26Over the next six months she carefully tends her precious brood.

0:34:29 > 0:34:31She caresses them with her arms

0:34:31 > 0:34:36to keep them free of algae and properly supplied with oxygen.

0:34:38 > 0:34:42This is her first and only brood.

0:34:42 > 0:34:45And so she takes great care of them.

0:34:45 > 0:34:50While she's guarding her eggs she doesn't leave the den.

0:34:50 > 0:34:52Not once.

0:34:52 > 0:34:53Unable to feed,

0:34:53 > 0:34:55she is starving.

0:34:55 > 0:35:02Her last act of devotion is to blow water over the eggs to help them hatch.

0:35:20 > 0:35:23Young, fully-developed octopus pop out.

0:35:28 > 0:35:34Though only a few will survive to adulthood, she's given them the best chance she can.

0:35:37 > 0:35:41After her long and lonely vigil,

0:35:41 > 0:35:43she is dead.

0:35:43 > 0:35:48Surely this sacrifice must make her one of nature's most devoted mothers.

0:35:59 > 0:36:05Here, 30 metres beneath the Costa Rican forest canopy, another dedicated mother

0:36:05 > 0:36:09ensures that her young also have the best possible start in life.

0:36:15 > 0:36:23This tiny strawberry poison arrow frog, only the size of a finger nail, is guarding her fertilised eggs.

0:36:26 > 0:36:31Whilst the eggs and tadpoles are developing, she and her mate keep

0:36:31 > 0:36:35watch, making sure that they are safe from predators.

0:36:35 > 0:36:39But they can't stay here for ever.

0:36:39 > 0:36:42The leaf litter is drying out and tadpoles need water.

0:36:42 > 0:36:45She must do something, and fast.

0:36:53 > 0:36:58She needs to move them and so encourages one tadpole to climb on her back.

0:36:59 > 0:37:01She now begins an epic journey.

0:37:02 > 0:37:06But it's not to a pond, as you might expect,

0:37:06 > 0:37:09she is looking for something very particular.

0:37:09 > 0:37:18Her journey takes her across the forest floor to the foot of a tall tree and then she starts to climb.

0:37:33 > 0:37:36For such a little frog it is a marathon ascent,

0:37:36 > 0:37:42like a human mother climbing the Empire State Building with a child on her back.

0:37:45 > 0:37:50She's looking for a plant, a bromeliad, growing on the tree.

0:37:55 > 0:38:03It holds a pool of water at its centre, the perfect nursery pool for a developing tadpole.

0:38:06 > 0:38:09In slides her youngster.

0:38:16 > 0:38:19But this is only one of six tadpoles.

0:38:19 > 0:38:23She must rush back down to rescue the others.

0:38:28 > 0:38:33One by one she collects them and carries each to its own bromeliad.

0:38:56 > 0:38:59But there is another problem.

0:38:59 > 0:39:01The little pools contain no food.

0:39:05 > 0:39:07So she has to provide it.

0:39:07 > 0:39:13She lays an unfertilised egg in each pool for her tadpoles to eat.

0:39:19 > 0:39:22And then she leaves.

0:39:27 > 0:39:31But one egg won't sustain a growing tadpole for long,

0:39:31 > 0:39:35so she has to return every few days with another egg.

0:39:42 > 0:39:47Over the next two weeks she can climb almost half a mile tending her young.

0:39:49 > 0:39:52An astonishing feat for such a tiny creature.

0:40:01 > 0:40:04While she's busy delivering eggs,

0:40:04 > 0:40:08the tadpole grows legs and its tail begins to disappear.

0:40:10 > 0:40:14And then one day it leaves its bromeliad nursery for ever

0:40:14 > 0:40:17and climbs out into the forest.

0:40:22 > 0:40:26Whilst its mother has a well-deserved rest.

0:40:30 > 0:40:33Birds are also diligent parents.

0:40:33 > 0:40:38Over their lifetime they invest huge effort in just a few young.

0:40:43 > 0:40:46But there is only so much a parent can do.

0:40:50 > 0:40:56All along the Antarctic peninsula both male and female chinstrap penguins have been commuting

0:40:56 > 0:41:00daily from the open ocean to collect food for their chicks.

0:41:08 > 0:41:13Mouthfuls of krill, caught many miles away at sea, are regurgitated.

0:41:22 > 0:41:26But one day the chicks wait in vain for food.

0:41:26 > 0:41:28Their parents do not return.

0:41:30 > 0:41:33The chicks now face life on their own.

0:41:33 > 0:41:37This is the toughest time in an animal's life

0:41:37 > 0:41:40and some are not going to make it.

0:41:46 > 0:41:51Over the next few days, driven by hunger, the chicks make their way down to the shore.

0:41:53 > 0:41:57Instinct tells them they have to head out to sea.

0:42:00 > 0:42:05Built to withstand the cold, they have already accumulated

0:42:05 > 0:42:09a layer of fat, and their outer feathers act as a waterproof shield.

0:42:11 > 0:42:14But they still have to learn to swim.

0:42:37 > 0:42:40The polar sea is challenging enough

0:42:40 > 0:42:42but with a change in the wind,

0:42:42 > 0:42:46a slick of broken ice has choked the bay.

0:42:50 > 0:42:54For any penguin this ice presents a real problem.

0:42:56 > 0:42:59But for the chicks it's a disaster.

0:43:04 > 0:43:09They must get through this barrier to the open water, if they are to feed.

0:43:15 > 0:43:18One, perhaps hungrier or braver than the rest,

0:43:18 > 0:43:23leads the way and tries skittering over the top, while the others watch.

0:43:25 > 0:43:30The ice is hard to swim through, and progress is painfully slow.

0:43:52 > 0:43:54A leopard seal.

0:44:00 > 0:44:04This chick never had the chance to learn how to avoid the seal.

0:44:04 > 0:44:07Its end is inevitable.

0:44:32 > 0:44:38The leopard seal efficiently flays the chick, tearing off a small piece with each throw.

0:44:42 > 0:44:45Others take their chance.

0:45:24 > 0:45:28But the leopard seal is now ready for its next victim.

0:45:46 > 0:45:51It's a lottery, and the lucky chicks make it out to open water.

0:45:55 > 0:46:02There is still an element of chance in life which an individual can do little about.

0:46:26 > 0:46:29In the end, overcoming life's challenges,

0:46:29 > 0:46:33whether finding enough to eat or outwitting your predators,

0:46:33 > 0:46:38is only significant if life's final challenge can be met.

0:46:45 > 0:46:53From a tiny frog dedicating weeks to her few cherished tadpoles, to an orang-utan who spends

0:46:53 > 0:46:56eight years bringing up her baby,

0:46:56 > 0:47:00individual animals strive to reach this one ultimate goal,

0:47:00 > 0:47:07to pass on their genes and to ensure the survival of the next generation.

0:47:09 > 0:47:12Ultimately, in nature,

0:47:12 > 0:47:16that is what life is all about.

0:48:01 > 0:48:05During the three years it took to film Life, our camera crews

0:48:05 > 0:48:10visited every continent on Earth, but the most challenging was Antarctica.

0:48:14 > 0:48:16Here filming was only possible

0:48:16 > 0:48:22with the help of an extraordinary range of people and organisations.

0:48:22 > 0:48:26An Air Force jet delivering supplies to McMurdo research station

0:48:26 > 0:48:31ferried one of our crews to the Ross Ice Shelf.

0:48:38 > 0:48:42And on the other side of the continent a team sailed for five days

0:48:42 > 0:48:46across the Drake Passage to reach the Antarctic peninsula.

0:48:48 > 0:48:52Once there, a small crew was put ashore on Deception Island

0:48:52 > 0:48:56to spend a month camping on the edge of a penguin colony.

0:48:58 > 0:49:02Two people and 200,000 penguins.

0:49:09 > 0:49:11Another team joined scientists

0:49:11 > 0:49:13drilling through the ice

0:49:13 > 0:49:16to explore the beautiful and bizarre world below.

0:49:36 > 0:49:41But the hardiest and most ambitious shoot involved four film crews,

0:49:41 > 0:49:46a celebrated French yachtsman and the Ministry of Defence.

0:49:49 > 0:49:52The teams had a two-month window

0:49:52 > 0:49:57to film Antarctica's two top predators in action.

0:49:57 > 0:50:00We knew that one could be found prowling the coast of

0:50:00 > 0:50:06Rosenthal Island, waiting for young penguins to take their first plunge.

0:50:06 > 0:50:10And the man to take us there was Jerome Poncet.

0:50:10 > 0:50:17He skippered the first yacht to sail south of the Antarctic Circle and has been back every year for the past 35.

0:50:17 > 0:50:20He knows Antarctic sailing like no-one else.

0:50:21 > 0:50:25His yacht, the Golden Fleece, is not an ice breaker,

0:50:25 > 0:50:29but Jerome has his own unique way of getting through.

0:50:30 > 0:50:33He shunts one floe against another

0:50:33 > 0:50:36to clear a way through like playing marbles.

0:50:36 > 0:50:39Jerome, once he gets his teeth into,

0:50:39 > 0:50:42into a situation he doesn't like to let it go.

0:50:42 > 0:50:45So, maybe we'll be here for a few hours yet.

0:50:45 > 0:50:49Jerome is determined to get through this channel.

0:50:49 > 0:50:52We talk about hundred, hundreds of tonnes,

0:50:52 > 0:50:56maybe 1,000, 250,000 tonnes or more.

0:50:58 > 0:51:00It's a pooling of water, you have to push.

0:51:03 > 0:51:06Some marbles are just too big.

0:51:11 > 0:51:15For now, Jerome is foiled and has to moor for the night.

0:51:15 > 0:51:20For him, tying up to 100,000 tonnes of ice

0:51:20 > 0:51:23is just another day at the office.

0:51:30 > 0:51:35Progress is slow, but they need to get to Rosenthal before the penguins leave.

0:51:37 > 0:51:41They make it through and the penguins are still there.

0:51:43 > 0:51:48Chinstrap penguin chicks fledge at a particular time of year.

0:51:48 > 0:51:52The crew knew this would draw leopard seals like a magnet.

0:51:53 > 0:51:57Leopard seals are giants among their kind, they have teeth

0:51:57 > 0:52:02bigger than a lion and a mouth that can open nearly 180 degrees.

0:52:02 > 0:52:04How close can Doug get?

0:52:09 > 0:52:12With this seal, very.

0:52:29 > 0:52:32He loses interest in his reflection

0:52:32 > 0:52:35and goes back to eating penguins.

0:52:46 > 0:52:48That was very exciting.

0:52:48 > 0:52:51He was a super seal,

0:52:51 > 0:52:54super seal, gave me lots of action nice and close,

0:52:54 > 0:52:58but I must admit you do have to feel sorry for the penguin,

0:52:58 > 0:52:59just doesn't stand a chance.

0:52:59 > 0:53:02The team knew where to find leopard seals,

0:53:02 > 0:53:05but finding the other top predator

0:53:05 > 0:53:08was going to be another matter entirely.

0:53:09 > 0:53:13Very little is known about Antarctic killer whales.

0:53:13 > 0:53:15Time to bring in reinforcements.

0:53:18 > 0:53:21HMS Endurance,

0:53:21 > 0:53:25the Royal Navy's ice patrol ship.

0:53:28 > 0:53:34She surveys Antarctic waters and the crew see changes every year.

0:53:34 > 0:53:41The latest chart of this area, we are now six miles inside an ice shelf, which just goes to show

0:53:41 > 0:53:47how much retreation of this ice shelf has occurred over the past five or six years.

0:53:48 > 0:53:51Would you get complications...?

0:53:51 > 0:53:54Series producer Martha Holmes and cameraman David Baillie

0:53:54 > 0:53:59were on board to find and film the killer whales from the air.

0:53:59 > 0:54:03Endurance carries two Lynx helicopters used to assist

0:54:03 > 0:54:07the British Antarctic Survey and the Hydrographic Office.

0:54:07 > 0:54:08On this trip,

0:54:08 > 0:54:13some time on one of the helicopters is assigned to the Life team.

0:54:22 > 0:54:28No-one has succeeded in filming killer whales hunting off the Antarctic peninsula before.

0:54:28 > 0:54:33Our two teams have just a few days when they can film together.

0:54:41 > 0:54:44At water level the Golden Fleece has exciting news.

0:54:44 > 0:54:48They've found killer whales which look as though they could be hunting.

0:54:48 > 0:54:54And Navy 435, Navy 435, this is Golden Fleece, Golden Fleece over.

0:54:55 > 0:54:57INDISTINCT VOICE ON RADIO

0:54:57 > 0:55:00'Copy that. We're on our way.'

0:55:00 > 0:55:03Guys, really windy, we'll be...

0:55:03 > 0:55:08pretty lucky to stay with them through this. But we can try though.

0:55:18 > 0:55:23435, this is Golden Fleece, we have lost sight of the orca.

0:55:26 > 0:55:30- The white.- 'Yeah, OK, they're in direct line with that iceberg now,

0:55:30 > 0:55:33'between us and the iceberg about 100 metres this side of it.'

0:55:33 > 0:55:36'Visual. Yeah, visual.'

0:55:36 > 0:55:42From the air, the helicopter team can follow the killer whales more easily than the boat team.

0:55:42 > 0:55:46435, this is Golden Fleece, full copy. Out.

0:55:50 > 0:55:56By working together the helicopter and yacht are able to keep track of the whales in the rough sea.

0:55:56 > 0:56:01'There's four now actually yes, four, and four I can see.'

0:56:01 > 0:56:05A change in the weather gives a chance to film at last.

0:56:06 > 0:56:10They've gone further up this way, if we follow them that's good.

0:56:13 > 0:56:15But will they hunt?

0:56:15 > 0:56:17OK, here they come through.

0:56:19 > 0:56:22Oops, yeah, they 1, 2, 3, 4, 5, 6, 7, 8, it's a good 12 huh, easy.

0:56:26 > 0:56:31Doug has spotted a crabeater seal near some ice, but have the killer whales seen it?

0:56:33 > 0:56:36No, just keep loosening the square screen.

0:56:51 > 0:56:52They have.

0:56:54 > 0:56:55Some good action.

0:56:57 > 0:56:59Can you go closer?

0:57:21 > 0:57:23It's over, that's it, they've got him.

0:57:26 > 0:57:28It's still there.

0:57:31 > 0:57:36For a wildlife cameraman there are always surprises.

0:57:39 > 0:57:44It has taken two months, but they've succeeded thanks to extraordinary

0:57:44 > 0:57:48collaboration from an entire ship's company to a lone skipper.

0:57:48 > 0:57:55Collaborations like this would be the foundation of the whole three years of filming across the world.

0:58:15 > 0:58:19Subtitles by Red Bee Media Ltd

0:58:19 > 0:58:23E-mail subtitling@bbc.co.uk