0:00:02 > 0:00:04'Across our planet, there are spectacular animals
0:00:04 > 0:00:07'united by one thing.
0:00:09 > 0:00:11'Their size.'
0:00:12 > 0:00:15These are nature's heavyweight champions.
0:00:15 > 0:00:18True masters of their environment.
0:00:18 > 0:00:19These are the supergiants.
0:00:23 > 0:00:26'I'm Steve Backshall and I'm travelling the world
0:00:26 > 0:00:29'to track down the most remarkable supergiants.
0:00:32 > 0:00:35'I want to witness their incredible abilities.'
0:00:35 > 0:00:36Yes!
0:00:36 > 0:00:39'Understand the challenges they face.'
0:00:39 > 0:00:42That tree was snapped like a matchstick.
0:00:43 > 0:00:47'And ultimately discover why size matters.'
0:00:47 > 0:00:48Wow, that's heavy!
0:00:48 > 0:00:51'I believe the best way to do that
0:00:51 > 0:00:54'is to encounter them in their world.'
0:00:54 > 0:00:58It's coming after us! It's coming right for us!
0:01:09 > 0:01:12'Supergiants are unique individuals.
0:01:12 > 0:01:16'They dominate their worlds and out-compete their rivals.
0:01:17 > 0:01:22'But being massive also brings immense challenges.
0:01:23 > 0:01:27'To begin to understand what life is like for a supergiant,
0:01:27 > 0:01:31'I'm looking for an animal that's mastered supersize so well,
0:01:31 > 0:01:35'it's remained unchanged for tens of millions of years.'
0:01:37 > 0:01:39This is the Okavango Delta.
0:01:39 > 0:01:43There's about 5,000 square miles of swampy wilderness here,
0:01:43 > 0:01:47and it's one of the great spots on the planet for wildlife.
0:01:47 > 0:01:51'I've come for an encounter with a predator that's so large,
0:01:51 > 0:01:53'nothing can challenge it.
0:01:54 > 0:01:57'The Nile crocodile.
0:01:57 > 0:01:59'These are Africa's biggest reptiles.
0:01:59 > 0:02:03'Up to six metres long and over a tonne in weight.
0:02:05 > 0:02:10'They combine raw power and speed with patience and stealth.
0:02:10 > 0:02:13'The result is one of the animal kingdom's most formidable
0:02:13 > 0:02:15'hunting techniques.
0:02:26 > 0:02:29'Nile crocodiles look impressive on land,
0:02:29 > 0:02:33'but the secret of their success and their size is found underwater,
0:02:33 > 0:02:37'so that's where I'll need to go.
0:02:48 > 0:02:50'In over 14 years filming wildlife,
0:02:50 > 0:02:53'this is potentially my most dangerous encounter.
0:03:02 > 0:03:04'Joining me is Brad Bestelink,
0:03:04 > 0:03:08'a film-maker who's lived in the Okavango his whole life.'
0:03:09 > 0:03:13So, from your experience, how big do the crocs here get?
0:03:13 > 0:03:19The biggest we've dived with has been about four-and-a-half metres.
0:03:19 > 0:03:23I'm guessing that you've had some pretty close calls with crocs over the years.
0:03:23 > 0:03:27- A big crocodile bit a hole in the side of this boat and sank this boat.- Seriously?!
0:03:27 > 0:03:31Yeah, an animal that big has got no problem going in and punching a hole.
0:03:31 > 0:03:35- It's quite a frightening animal. - Let's hope they don't punch a hole in us!
0:03:39 > 0:03:43'Crocodiles sunbathe to raise their body temperature.
0:03:43 > 0:03:46'The bigger crocs can store more heat
0:03:46 > 0:03:50'and the warmer their muscles, the faster they become.
0:03:51 > 0:03:55'When they're ready, they drop into the water to hunt.'
0:04:05 > 0:04:06Oh, croc!
0:04:07 > 0:04:10'My first chance to see one underwater.
0:04:14 > 0:04:18'The initial few seconds are one of the most dangerous parts of the dive.
0:04:22 > 0:04:25As soon as we hit the water, we have to drop straight down to the bottom
0:04:25 > 0:04:29because the surface is the kill zone, where we're most vulnerable and most exposed.
0:04:31 > 0:04:34'Crocodiles usually ambush their victims from below,
0:04:34 > 0:04:38'so being above them could trigger an attack.'
0:04:42 > 0:04:46Three...two...one.
0:04:54 > 0:04:57'The Okavango is the only place on Earth
0:04:57 > 0:05:00'where diving with these predators is possible.'
0:05:02 > 0:05:04Firstly, because the water's so clear,
0:05:04 > 0:05:08there's much less chance of them creeping up on you unawares.
0:05:09 > 0:05:12But also, this time of year, the water is quite chilly.
0:05:12 > 0:05:15It means that they're much less likely to be aggressive.
0:05:15 > 0:05:19But, I have to say, it's still a nerve-wracking experience.
0:05:21 > 0:05:24'Their camouflage allows them to disappear
0:05:24 > 0:05:27'in this labyrinth of overhanging vegetation.'
0:05:34 > 0:05:37And we have a croc. We have a crocodile.
0:05:44 > 0:05:47I'm just going to edge forward very, very carefully.
0:05:50 > 0:05:53'This crocodile is around three metres
0:05:53 > 0:05:56'and, from its proportions, is probably a female.'
0:05:56 > 0:06:01And at this size, it wouldn't struggle at all with a human being,
0:06:01 > 0:06:06so, to be lying right next to it, to have its tail...
0:06:06 > 0:06:11right down at my knees... is an extraordinary experience.
0:06:15 > 0:06:19The ability to just sit here not expending any energy
0:06:19 > 0:06:21is really important for crocodiles.
0:06:23 > 0:06:26They can lie in wait or ambush for their prey
0:06:26 > 0:06:30for many days at a time if they have to.
0:06:31 > 0:06:35'Large crocodiles can go six months between meals.
0:06:46 > 0:06:50'But when they do encounter a potential victim,
0:06:50 > 0:06:54'they are equipped to burst into action.'
0:06:55 > 0:07:00This broad, flat, paddle-shaped tail...
0:07:00 > 0:07:04at the base here...has enormous amounts of muscle
0:07:04 > 0:07:09which can drive it from side to side as it powers off.
0:07:09 > 0:07:12It can use that for explosive force,
0:07:12 > 0:07:16thrusting it out of the water to catch prey at the water's edge.
0:07:17 > 0:07:21'And the larger the crocodile, the more power it can generate.
0:07:22 > 0:07:25'This female is half the length of the biggest crocs,
0:07:25 > 0:07:28'but she can swim incredibly quickly.'
0:07:28 > 0:07:32Once they get moving, there's simply no way you're going to keep up,
0:07:32 > 0:07:35especially not into the current.
0:07:35 > 0:07:38They can drive themselves on with total ease.
0:07:38 > 0:07:41And I'm just going backwards!
0:07:45 > 0:07:47Our next challenge is to get back up to the boat.
0:07:47 > 0:07:51We need to get up and out of the water as quickly as possible.
0:08:06 > 0:08:09Oh! That was incredible.
0:08:09 > 0:08:11I just can't believe
0:08:11 > 0:08:15how much she allowed us to be close to her.
0:08:15 > 0:08:19We were right on top of her and just not bothered by us at all.
0:08:19 > 0:08:21So chilled out.
0:08:21 > 0:08:24What a wonderful animal.
0:08:24 > 0:08:29But this is probably as large as female crocodiles get.
0:08:29 > 0:08:32The males are the ones that get to be really enormous.
0:08:37 > 0:08:39'I really want to find a large male
0:08:39 > 0:08:42'and get a sense of its power underwater.
0:08:44 > 0:08:47'So we're continuing upriver to look for one.
0:08:55 > 0:08:59'And that appears to be a giant.'
0:08:59 > 0:09:01Yeah. Hey, it's a big croc, eh?
0:09:05 > 0:09:09I've just seen a really good-sized crocodile slide into the water
0:09:09 > 0:09:12and we're just trying to get a handle on where it is.
0:09:32 > 0:09:34It's even more gloomy and sinister now.
0:09:50 > 0:09:53Ah, I see it, I see it!
0:09:53 > 0:09:56Our supergiant croc up ahead of us...
0:09:56 > 0:09:59he is a true monster.
0:10:01 > 0:10:06I'm having to do all I can... to keep my heart rate down.
0:10:13 > 0:10:19The last thing I want is for him to sense...any fear from me.
0:10:29 > 0:10:33It's a whole different scale.
0:10:33 > 0:10:37He's probably...over four metres in length.
0:10:37 > 0:10:40It could be four-and-a-half.
0:10:44 > 0:10:47This animal is standing up,
0:10:47 > 0:10:51menacing, threatening, alert.
0:10:51 > 0:10:55I'm really not that comfortable being so close to him.
0:10:55 > 0:11:00It's one of the most chilling experiences I've ever had.
0:11:04 > 0:11:07'A crocodile of this size could be 50 years old
0:11:07 > 0:11:12'and would have no trouble taking an adult wildebeest or me.'
0:11:13 > 0:11:16This is the closest I've ever been
0:11:16 > 0:11:19to lying alongside a dinosaur.
0:11:36 > 0:11:39'The massive male makes for the surface.
0:11:46 > 0:11:51'But simply takes a breath and heads straight back down towards us.'
0:11:52 > 0:11:55It's coming after us.
0:11:58 > 0:12:00It's following us along the bottom!
0:12:11 > 0:12:15'Big males battle to dominate their territories.
0:12:17 > 0:12:20'He clearly sees us as a challenge.
0:12:23 > 0:12:27'We've no choice but to risk a dash for the surface.'
0:12:45 > 0:12:49Well, that was without a doubt the most frightening experience
0:12:49 > 0:12:51I've ever had with an animal.
0:12:52 > 0:12:56There was one point where he came up to the surface
0:12:56 > 0:13:01and then he dropped down and headed straight for us.
0:13:01 > 0:13:05There was a great cloud of sand went up
0:13:05 > 0:13:07and I lost sight of the two guys.
0:13:07 > 0:13:10All I could see was lights twirling around
0:13:10 > 0:13:13and he's sat on the surface right back there now,
0:13:13 > 0:13:16a completely different attitude,
0:13:16 > 0:13:20completely different animal to any of the others we've seen.
0:13:21 > 0:13:26'By growing enormous, male Nile crocodiles become dominant.
0:13:29 > 0:13:34'They retain enough heat to hunt for longer underwater than their rivals.
0:13:36 > 0:13:40'And the biggest, meanest males command the best territories.
0:13:51 > 0:13:55'Being a supergiant can be a huge benefit.
0:13:58 > 0:14:02'But on dry land, it's much more challenging.
0:14:05 > 0:14:09'I've travelled to South Africa to discover how some supergiants
0:14:09 > 0:14:12'solve the problems that size brings.'
0:14:14 > 0:14:17Africa really is a land of giants,
0:14:17 > 0:14:20home to the largest of all land animals.
0:14:21 > 0:14:26'The hippo, rhino and Cape buffalo are all massive,
0:14:26 > 0:14:29'but the supergiant I've come to find
0:14:29 > 0:14:33'can outweigh all three of these combined.'
0:14:33 > 0:14:36They can run down a human being in full sprint,
0:14:36 > 0:14:39they'll destroy pretty much anything in their path.
0:14:39 > 0:14:41They are an unstoppable force of nature.
0:14:41 > 0:14:46'The African elephant is the biggest land animal on the planet.
0:14:47 > 0:14:52'The record-holder was hunted in Angola in 1955.
0:14:52 > 0:14:57'It was four metres tall and had footprints the size of dustbin lids.
0:14:57 > 0:15:01'At over ten tonnes, it weighed more than a T. rex.
0:15:06 > 0:15:09'Today, there aren't so many giant elephants left,
0:15:09 > 0:15:11'but I've tracked one down.'
0:15:13 > 0:15:18Below me now is Addo Elephant Park. It covers about 700 square miles,
0:15:18 > 0:15:22which makes it the third largest reserve in South Africa.
0:15:22 > 0:15:25There's about 500 elephants here.
0:15:27 > 0:15:31'Over the last century, hunting removed all the big ones.'
0:15:33 > 0:15:35So a few years ago they came up with a solution.
0:15:35 > 0:15:38They decided to bring in a supergiant male
0:15:38 > 0:15:40to try and bolster the gene pool.
0:15:41 > 0:15:44'The elephant's called Vallie,
0:15:44 > 0:15:47'and we're hoping to pick up the signal from his radio collar.'
0:15:47 > 0:15:50Here he is. This is him. This is the animal.
0:15:50 > 0:15:52He is enormous!
0:15:54 > 0:15:57'Vallie is one of the largest elephants in the world.'
0:15:58 > 0:16:02The best way of getting a real sense of quite how big this animal is,
0:16:02 > 0:16:04is to approach him on the ground.
0:16:15 > 0:16:18It's been a long time since I've seen an animal
0:16:18 > 0:16:20that has that size tusks.
0:16:20 > 0:16:23They're becoming all too rare nowadays.
0:16:38 > 0:16:42When Vallie had his radio collar fitted, all of his measurements were taken.
0:16:42 > 0:16:45He stands 3.4 metres at the shoulder,
0:16:45 > 0:16:48which means he's taller than our bus that we're driving around in.
0:16:52 > 0:16:56'An elephant of this size weighs around six tonnes
0:16:56 > 0:16:59'and no other animal around here could challenge him.
0:17:02 > 0:17:05'But his life in Addo isn't easy.
0:17:06 > 0:17:09'The temperature regularly tops 40 degrees Celsius.
0:17:12 > 0:17:17'It's tough here, and even harder if you have a massive body.'
0:17:19 > 0:17:23To see an animal of this size in the absolute prime of his life
0:17:23 > 0:17:25up close, on foot,
0:17:25 > 0:17:29is one of the great privileges of being here in Africa.
0:17:33 > 0:17:35'But as wild elephants can be dangerous,
0:17:35 > 0:17:38'to get a more intimate idea of scale
0:17:38 > 0:17:40'I'll need a friendlier supergiant.'
0:17:53 > 0:17:56There are very few bull African elephants in the world
0:17:56 > 0:18:00you could stand this close to, but Tembo's very special.
0:18:00 > 0:18:03And trust me, when you're in the shadow of a giant,
0:18:03 > 0:18:05you feel very, very small.
0:18:06 > 0:18:11'He's over three metres tall and very used to being around people.'
0:18:11 > 0:18:15You might think that, being this size, life would be easy.
0:18:15 > 0:18:17You don't have to worry about any predators.
0:18:17 > 0:18:20But for a supergiant, life is just packed with challenges.
0:18:20 > 0:18:25'It takes over 200 kilos of food every day
0:18:25 > 0:18:27'to fuel a body this size.
0:18:31 > 0:18:35'So elephants will stop at nothing to get a meal.'
0:18:37 > 0:18:41In the wild, elephants are capable of taking down really large trees
0:18:41 > 0:18:45in the hope of getting to the foliage up in the canopy.
0:18:54 > 0:18:56How about that?
0:18:58 > 0:19:02'An elephant's trunk has around 60,000 muscles.'
0:19:12 > 0:19:17This is that tree trunk that Tembo was twirling like a twig.
0:19:23 > 0:19:26I actually didn't think it was going to be that heavy!
0:19:26 > 0:19:28Wow!
0:19:29 > 0:19:32There must be a tonne of trunk here.
0:19:33 > 0:19:35And for him it was absolutely effortless.
0:19:38 > 0:19:41'This strength gives elephants access to food
0:19:41 > 0:19:43'others can't take advantage of.
0:19:46 > 0:19:50'But these giants may have to cover hundreds of miles to find food.
0:19:54 > 0:19:57'And if you weigh the same as four family cars,
0:19:57 > 0:20:00'that takes some clever engineering.'
0:20:01 > 0:20:04There's something very, very special about the feet
0:20:04 > 0:20:06that I'd really like to show you.
0:20:06 > 0:20:10About 60% of the weight is coming through these two front legs,
0:20:10 > 0:20:13so he has enormous, pillar-like bones
0:20:13 > 0:20:17which allow all of the weight to be driven down into these huge feet.
0:20:17 > 0:20:20Elephants effectively walk on their toes,
0:20:20 > 0:20:25so this area is where the foot bones are - you can see the toenails,
0:20:25 > 0:20:29and all of this area here is fat.
0:20:29 > 0:20:32It's a huge, fatty shock-absorber.
0:20:35 > 0:20:38'The giant pads cushion the feet.
0:20:38 > 0:20:41'With each step, the fat spreads out,
0:20:41 > 0:20:44'distributing the load over a greater area.
0:20:46 > 0:20:52'When they lift their foot, the fat contracts and the foot gets smaller.
0:20:54 > 0:20:57'This helps them avoid getting stuck in the mud.
0:21:00 > 0:21:06'While that's ingenious, these titans also face an extra challenge.
0:21:07 > 0:21:10'Overheating in the African sun.
0:21:12 > 0:21:16'The solution is their colossal ears.'
0:21:19 > 0:21:23Even just standing here now, I can feel from the mechanical action
0:21:23 > 0:21:25of them flapping backwards and forwards,
0:21:25 > 0:21:28it is genuinely cooling, but it's much more than that.
0:21:28 > 0:21:31Running close to the surface of the skin is a dense
0:21:31 > 0:21:35network of capillaries, filled with warm blood.
0:21:35 > 0:21:38As the air moves over the ears, it cools the blood down,
0:21:38 > 0:21:42which is then returned to the body, bringing down the overall body temperature.
0:21:43 > 0:21:47'Tembo can cycle almost 1,000 litres of blood
0:21:47 > 0:21:50'through his ears every hour,
0:21:50 > 0:21:53'cooling it by up to nine degrees in the process.
0:21:54 > 0:21:59'Without their vast ears, elephants wouldn't be able to survive here.
0:22:01 > 0:22:04'Having solved the problems of their size,
0:22:04 > 0:22:07'elephants can thrive across much of Africa.
0:22:08 > 0:22:14'In their endless search for food, they've become nature's landscapers.
0:22:18 > 0:22:21'Another solution to the problems of supersize
0:22:21 > 0:22:26'is to escape the drag of gravity by living in the ocean.
0:22:27 > 0:22:30'Off the coast of Africa lurks another supergiant
0:22:30 > 0:22:32'that does just that.
0:22:33 > 0:22:36'The great white shark.
0:22:39 > 0:22:41'It's the perfect hunting machine.
0:22:44 > 0:22:48'Some truly gargantuan great whites have been pulled from the ocean.
0:22:49 > 0:22:54'Over six metres long and two tonnes in weight.
0:23:00 > 0:23:05'Some of the largest ever seen have been recorded off the coast of South Africa.'
0:23:12 > 0:23:17So this is the reason why there is such an abundance of great white sharks here in False Bay.
0:23:17 > 0:23:20On this rocky island, there are over 70,000 Cape fur seals.
0:23:25 > 0:23:30'To find out why supergiant sharks are so successful here,
0:23:30 > 0:23:33'the best place to start is underwater
0:23:33 > 0:23:35'with the animals they hunt.'
0:23:40 > 0:23:42Cape fur seals.
0:23:42 > 0:23:46They've got a really graceful, elegant, agile way about them
0:23:46 > 0:23:48underwater.
0:23:49 > 0:23:51They have all these senses on display.
0:23:51 > 0:23:55The enormous eyes - they've got fantastic eyesight.
0:23:55 > 0:23:58And all those whiskers make them very, very sensitive
0:23:58 > 0:24:02to everything that's going on in the water around them.
0:24:02 > 0:24:03They're so aware.
0:24:03 > 0:24:09It's their manoeuvrability - the fact that they can twist and turn
0:24:09 > 0:24:11and move at such speed.
0:24:11 > 0:24:14It's an animal that's almost impossible to catch.
0:24:18 > 0:24:22'But somehow, great whites manage to eat thousands of seals here
0:24:22 > 0:24:24'every year.
0:24:29 > 0:24:31'To find out how,
0:24:31 > 0:24:35'we're going to need to see a great white at work.'
0:24:37 > 0:24:40So this is how you attract the attention of a shark.
0:24:40 > 0:24:42It's called chumming.
0:24:42 > 0:24:45What we're doing is creating a thin slick of blood and oil.
0:24:45 > 0:24:48Sharks can sense just a tablespoon of blood
0:24:48 > 0:24:51in an Olympic swimming pool of water,
0:24:51 > 0:24:54and can pick up blood from well over a mile away.
0:24:56 > 0:25:00I know it's hard to guesstimate but, for you, the biggest that you've ever seen here?
0:25:00 > 0:25:03The biggest shark I've ever seen at Seal Island
0:25:03 > 0:25:05- is about five-and-a-half metres. - Five-and-a-half?
0:25:05 > 0:25:08That's enormous. I mean, that must be the size of a bus!
0:25:08 > 0:25:11You think it's a whale when it approaches the boat.
0:25:13 > 0:25:17'Even a giant shark will barely break the surface.
0:25:18 > 0:25:20'To get a true sense of scale,
0:25:20 > 0:25:24'we need to be eye-to-eye and underwater.
0:25:26 > 0:25:29'Shark cages are the safest way to get close.
0:25:29 > 0:25:32'On occasion, too close!'
0:25:43 > 0:25:45Big shark! Whoa, that's a big shark!
0:25:45 > 0:25:49'After hours of waiting, a shark finally appears.
0:25:49 > 0:25:53'Time for me to get into the cage.'
0:25:54 > 0:25:57We have an enormous great white shark
0:25:57 > 0:25:59circling around behind the boat.
0:25:59 > 0:26:01This is exactly what we'd hoped for.
0:26:01 > 0:26:04She is absolutely colossal.
0:26:05 > 0:26:08Probably the biggest great white I've ever seen.
0:26:12 > 0:26:15Go down in, go in, go in, go in!
0:26:19 > 0:26:24We've been lowered down to about three metres below the surface.
0:26:26 > 0:26:31'It's here that the great white's array of senses are on display.'
0:26:33 > 0:26:36Wow, did you see how close that was?
0:26:36 > 0:26:38It came rocketing past the cage.
0:26:38 > 0:26:42'From a distance, the shark is drawn in by smell.
0:26:42 > 0:26:47'But when it gets close, it fixes on food using its sight.
0:26:50 > 0:26:54'Great whites' eyes are incredibly sensitive.
0:26:57 > 0:27:00'Next, electrical sensors in the snout
0:27:00 > 0:27:03'analyse the food from close range.
0:27:09 > 0:27:14'Once the shark realises this is an easy meal, it attacks.'
0:27:18 > 0:27:20Oh, look at that!
0:27:20 > 0:27:23Right over the top of us,
0:27:23 > 0:27:26thrashing about like crazy.
0:27:30 > 0:27:33'The water around me is cold...
0:27:33 > 0:27:36'too cold for most types of shark to function,
0:27:36 > 0:27:40'but great whites have a special ability.'
0:27:42 > 0:27:46One of the reasons they can thrive in waters like these
0:27:46 > 0:27:50is that, unlike most fish, they're warm-blooded.
0:27:51 > 0:27:55'They use their massive muscles to heat their blood.'
0:27:56 > 0:27:58It means they can carry on functioning
0:27:58 > 0:28:01at the absolute apex of their abilities.
0:28:02 > 0:28:04'These lunges are fine for scavenging,
0:28:04 > 0:28:08'but when the sharks are hunting highly manoeuvrable seals,
0:28:08 > 0:28:10'they need to step up their game.'
0:28:11 > 0:28:15The great white shark's secret is an attack that is one of the most
0:28:15 > 0:28:18incredible spectacles in the whole natural world.
0:28:22 > 0:28:25'And to witness that, we need to change tactics...
0:28:28 > 0:28:31'..by using this.'
0:28:32 > 0:28:34It's a decoy, just really a chunk of fibreglass
0:28:34 > 0:28:37made in the shape of a Cape fur seal.
0:28:37 > 0:28:40And on the top, this is our very own black box recorder.
0:28:40 > 0:28:44This measures G-force at the moment of strike.
0:28:44 > 0:28:47Essentially, this is going to tell us how it feels
0:28:47 > 0:28:49to be hit by a great white shark.
0:28:55 > 0:28:58'The decoy also has a built-in camera.'
0:29:06 > 0:29:09Glad it's him out there and not me.
0:29:10 > 0:29:13'What we're hoping for is known as a breach.
0:29:16 > 0:29:18'Conditions are perfect.
0:29:18 > 0:29:21'Great whites prefer to hunt in low light
0:29:21 > 0:29:24'as it gives them an element of surprise.'
0:29:24 > 0:29:27The longer this weather continues,
0:29:27 > 0:29:29the better our chances of seeing a breach.
0:29:45 > 0:29:46Yes!
0:29:46 > 0:29:50That was exactly what we've been hoping to see.
0:29:50 > 0:29:53A full, leaping breaching attack.
0:29:53 > 0:29:56It was an enormous animal and it completely cleared the water.
0:29:56 > 0:29:59The tail must have been two-and-a-half, even three metres
0:29:59 > 0:30:01out of the waves.
0:30:01 > 0:30:05The force that must be generated to get an animal of that size
0:30:05 > 0:30:08clear of the water must be unimaginable.
0:30:08 > 0:30:11'But how hard did that shark hit the decoy?'
0:30:11 > 0:30:14Right, I want to bring it in quickly now because the last thing we want
0:30:14 > 0:30:18is a great white breaching right up onto the boat.
0:30:19 > 0:30:23Well, if this was a real seal, it would be in a lot worse
0:30:23 > 0:30:25condition than that.
0:30:30 > 0:30:34Kind of miraculous, but this does still seem to be functioning.
0:30:34 > 0:30:36And let's see what we recorded.
0:30:37 > 0:30:41The highest it's recorded is 5G of force
0:30:41 > 0:30:44as this decoy was being carried upwards by our shark.
0:30:44 > 0:30:47That's the same as a fighter jet in a tight turn.
0:30:47 > 0:30:51And if you can imagine that, that kind of force being delivered
0:30:51 > 0:30:53by an animal that could be a tonne in weight
0:30:53 > 0:30:57with 300 scalpel-sharp teeth, it would be simply unstoppable.
0:30:57 > 0:31:01If this was a real seal, right now it would be in tatters.
0:31:02 > 0:31:06This is a devastating predatory technique.
0:31:06 > 0:31:08The shark's eyes,
0:31:08 > 0:31:11pressure and electrical sensors lock on to its target.
0:31:12 > 0:31:17With a few flicks of its tail, it accelerates to 20 miles an hour.
0:31:26 > 0:31:30The force of the impact drives the entire animal clear of the water.
0:31:40 > 0:31:44The decoy is continuing to attract large great whites.
0:31:56 > 0:31:57Played in real-time,
0:31:57 > 0:32:00we get an insight into why breaches are so lethal.
0:32:02 > 0:32:06Seals only have a tenth of a second to react.
0:32:12 > 0:32:15And finally we witness a breach by a giant great white.
0:32:20 > 0:32:25The decoy is 90 centimetres.
0:32:26 > 0:32:29Using it as a scale,
0:32:29 > 0:32:33this shark is around five metres long.
0:32:36 > 0:32:38This is a true supergiant.
0:32:38 > 0:32:41Seen fully out of the water, you can understand why
0:32:41 > 0:32:45it's one of the most lethal predators on the planet.
0:33:02 > 0:33:05Being a supergiant allows animals to break the rules,
0:33:05 > 0:33:10and in Florida one species has used that ability to invade
0:33:10 > 0:33:13and conquer a totally new habitat.
0:33:14 > 0:33:18The Everglades is probably my favourite part of the whole of North America.
0:33:18 > 0:33:21Firstly, because it's very wild and untameable,
0:33:21 > 0:33:24but secondly, because it is fantastic for wildlife.
0:33:26 > 0:33:29These wetlands are home to America's biggest reptiles.
0:33:32 > 0:33:36Alligators, crocodiles and turtles all thrive in this wilderness.
0:33:36 > 0:33:40But there's one reptile that simply shouldn't be here,
0:33:40 > 0:33:43and it's out-competing all the others.
0:33:44 > 0:33:47The Burmese python.
0:33:47 > 0:33:49These snakes can reach six metres in length
0:33:49 > 0:33:52and weigh the same as a heavyweight boxer.
0:33:55 > 0:33:58The pythons are native to South-East Asia
0:33:58 > 0:34:00and first came to America as pets.
0:34:03 > 0:34:08Some were released or escaped. Now their numbers are growing.
0:34:12 > 0:34:16Over 2,000 have been caught in and around the national park.
0:34:20 > 0:34:23Nobody knows how many are loose in Florida now,
0:34:23 > 0:34:25it could be over 100,000.
0:34:31 > 0:34:35Larger and larger snakes are being pulled from the swamp.
0:34:37 > 0:34:41The longest so far was 5.7 metres.
0:34:45 > 0:34:47I want to get hands-on with a python,
0:34:47 > 0:34:52to discover how its size has allowed it to overwhelm an entire ecosystem.
0:34:54 > 0:34:57So, we've got here a really good-sized Burmese python.
0:35:01 > 0:35:02Oh, wow, that's heavy!
0:35:05 > 0:35:07So, this animal was caught about a year ago
0:35:07 > 0:35:11and it's used for training for local emergency services,
0:35:11 > 0:35:14so the people who might be finding snakes like these
0:35:14 > 0:35:17in people's back yards can use this snake
0:35:17 > 0:35:19to learn how to handle them.
0:35:19 > 0:35:22It's about twice as long as I am tall,
0:35:22 > 0:35:25and around about 40 kilos in weight,
0:35:25 > 0:35:29that's about the same as a really big dog.
0:35:29 > 0:35:34But this is just one long tube of solid muscle.
0:35:34 > 0:35:36This snake is so incredibly adaptable,
0:35:36 > 0:35:41and as long as there's nothing else that's feeding on it, it is unstoppable.
0:35:41 > 0:35:45The pythons are eating their way through the native wildlife.
0:35:45 > 0:35:49Professor Frank Mazzotti from the University of Florida
0:35:49 > 0:35:52has collected an extraordinary range of items they've swallowed.
0:35:55 > 0:35:58We're constantly surprised by the things we find in the stomach.
0:35:58 > 0:36:01In fact, we're still finding new prey items.
0:36:01 > 0:36:06This looks like it's probably the remains of a bobcat.
0:36:06 > 0:36:08The bobcat is so quick, so fast!
0:36:08 > 0:36:13Just the idea for that being overcome by a snake is incredible.
0:36:13 > 0:36:16This is the hoof from a deer and deer hair,
0:36:16 > 0:36:20and it takes quite a large python to eat an adult deer.
0:36:22 > 0:36:26This 34-kilo deer was found inside a five-metre python.
0:36:30 > 0:36:34Now here we've got something that must have been eaten by a bigger snake,
0:36:34 > 0:36:39because those are scales from a decent-sized alligator.
0:36:39 > 0:36:42That is correct. I'd say, I don't know, maybe six feet in size.
0:36:42 > 0:36:46So, an alligator that was as long as I am tall, and it's been eaten...
0:36:46 > 0:36:50- Eaten by a bigger python. - That's incredible!
0:36:50 > 0:36:55I guess what's clear, looking at this, is that nothing is safe here.
0:36:55 > 0:36:58That is true, we have a new top predator on the block,
0:36:58 > 0:37:01and it's the Burmese python.
0:37:01 > 0:37:05Snakes can't chew, but their skulls are supremely flexible,
0:37:05 > 0:37:09allowing them to swallow enormous prey, like alligators, whole.
0:37:12 > 0:37:16They can engulf objects four times wider than their own head,
0:37:16 > 0:37:20that's like me swallowing a car tyre.
0:37:20 > 0:37:23After squeezing this alligator to death,
0:37:23 > 0:37:26the python will take about an hour to swallow it.
0:37:29 > 0:37:32But they don't always succeed.
0:37:32 > 0:37:35This snake was found dead with an alligator inside it.
0:37:37 > 0:37:43The meal was so big, the snake simply ruptured.
0:37:46 > 0:37:50Pythons here are now pushing six metres.
0:37:50 > 0:37:54It's an amazing success story for this supergiant,
0:37:54 > 0:37:58but it's going to take a monumental human effort
0:37:58 > 0:38:02if the Everglades are ever to be rid of this alien invader.
0:38:05 > 0:38:08Either that or we learn to live with a new top predator
0:38:08 > 0:38:11in the swamps of southern Florida.
0:38:14 > 0:38:18Crocodiles, sharks and pythons all show that supergiants
0:38:18 > 0:38:22are incredibly successful hunters and dominate their environments.
0:38:24 > 0:38:29But another supergiant uses its power to dominate its own species.
0:38:33 > 0:38:36On the Pacific coast of the United States lives the biggest animal
0:38:36 > 0:38:40you can see on dry land anywhere in the Americas.
0:38:43 > 0:38:46For an idea of the scale of the supergiant we're here to find
0:38:46 > 0:38:48I've got a selection of skulls.
0:38:48 > 0:38:52This one belongs to a black bear and these are found right
0:38:52 > 0:38:56here in California, but it's totally dwarfed by this one.
0:38:57 > 0:38:59This is a grizzly bear,
0:38:59 > 0:39:04and the canine teeth on this one are about as long as my thumb.
0:39:04 > 0:39:08This is in the record books as being the largest land predator on Earth.
0:39:11 > 0:39:14So, this gargantuan skull must surely come from some
0:39:14 > 0:39:17prehistoric dinosaur, a sabre-toothed cat perhaps?
0:39:17 > 0:39:22Well, actually this supergiant is anything but extinct.
0:39:22 > 0:39:24In fact, they're increasing in number,
0:39:24 > 0:39:27there's said to be over 150,000 of them,
0:39:27 > 0:39:32and the best place to see them is on the beach just over there.
0:39:41 > 0:39:43These are elephant seals.
0:39:43 > 0:39:46It's pretty obvious where the name comes from.
0:39:46 > 0:39:50I mean, that size, the skin and that extraordinary nose.
0:39:50 > 0:39:52They do just look like swimming elephants.
0:39:54 > 0:39:58Elephant seals are the biggest seals on the planet.
0:39:59 > 0:40:04The largest can be six metres long, and a whopping four tonnes.
0:40:06 > 0:40:08I want to see for myself
0:40:08 > 0:40:12why elephant seals have become supergiants.
0:40:14 > 0:40:17It's important to respect their personal space.
0:40:19 > 0:40:22Elephant seals rarely cross paths with people,
0:40:22 > 0:40:27but when they do, they can really throw their weight around.
0:40:38 > 0:40:42Up here on land, they're impossibly ungainly and out of place.
0:40:44 > 0:40:48But for these female elephant seals, there's still one part of their life
0:40:48 > 0:40:51where they're totally bound to the land.
0:40:51 > 0:40:53They come here to give birth...
0:40:53 > 0:40:56- SEAL ROARS - All right!
0:40:58 > 0:41:00..and to find a man.
0:41:01 > 0:41:05It's the male elephant seals that are the real supergiants.
0:41:05 > 0:41:08They're over three times heavier than the females.
0:41:10 > 0:41:13The males have to fight for mates.
0:41:13 > 0:41:16The bigger they are, the better their chances of success.
0:41:19 > 0:41:23Thanks to scientists from the University of California, Santa Cruz,
0:41:23 > 0:41:27I can get hands-on with one to see how it's equipped for battle.
0:41:28 > 0:41:32He's been sedated while the team attach a radio transmitter.
0:41:36 > 0:41:39It's remarkable, as the animal's breathing
0:41:39 > 0:41:44you can hear the air resonating around that huge nose.
0:41:44 > 0:41:46You can feel the vibrations coming up from the ground,
0:41:46 > 0:41:50it's like someone revving a big motorbike right next to you.
0:41:50 > 0:41:52DEEP SHUDDERING BREATHS
0:41:54 > 0:41:59Inside that mouth are four canine teeth - look a little bit like that.
0:41:59 > 0:42:04Particularly the two on the lower jaw are angled forward like this
0:42:04 > 0:42:07and can be used in a stabbing motion.
0:42:07 > 0:42:10If that was propelled at me I wouldn't last a second.
0:42:12 > 0:42:16Also the skin here is very, very heavy.
0:42:16 > 0:42:21I guess it functions almost like a suit of armour to stave off the worst blows.
0:42:21 > 0:42:223.88.
0:42:22 > 0:42:253.88?
0:42:25 > 0:42:27This male is four metres long.
0:42:28 > 0:42:34He's too heavy to weigh, but seal expert Dan Crocker can size him up.
0:42:34 > 0:42:35Just looking at him,
0:42:35 > 0:42:38I'd guess this male's about 1,500 kilos.
0:42:38 > 0:42:41That's more than three grand pianos!
0:42:43 > 0:42:46This enormous bulk, coupled with those tusk-like teeth,
0:42:46 > 0:42:49makes seal fights incredibly dangerous.
0:42:55 > 0:42:59Confrontations between males always begin with a shouting match.
0:42:59 > 0:43:03They're kind of like two guys in a pub car park after closing time,
0:43:03 > 0:43:07sizing each other up, just letting rip with that enormous bellow,
0:43:07 > 0:43:11and it resonates around that grotesque nose.
0:43:11 > 0:43:13SEALS GROWL
0:43:13 > 0:43:16The bigger the seal, the deeper its call.
0:43:16 > 0:43:20So, by bellowing, males can get the measure of each other.
0:43:20 > 0:43:22SEALS BELLOW
0:43:22 > 0:43:29These giants can sound off at 120 decibels -
0:43:29 > 0:43:30the same as a chain saw.
0:43:33 > 0:43:34If one animal's clearly larger,
0:43:34 > 0:43:37then the other will probably back down or be chased away.
0:43:37 > 0:43:41But if the two are more closely matched, then all hell breaks loose.
0:43:41 > 0:43:44GUTTURAL BELLOWS
0:43:49 > 0:43:52These two animals keep getting closer and closer,
0:43:52 > 0:43:55they're bellowing away and neither's willing to back down.
0:43:55 > 0:43:59When the odds are even, a battle begins.
0:43:59 > 0:44:02This is the key to why these animals get so big,
0:44:02 > 0:44:05where they truly are supergiants.
0:44:05 > 0:44:08When you see two males going head-to-head like this,
0:44:08 > 0:44:11tearing chunks out of each other,
0:44:11 > 0:44:14it is truly like one of the finest gladiatorial contests
0:44:14 > 0:44:18you'll see in the whole natural world.
0:44:18 > 0:44:21Already there's blood spilt everywhere,
0:44:21 > 0:44:23these two massive animals,
0:44:23 > 0:44:28tonnes and tonnes of blubber and muscle going head-to-head,
0:44:28 > 0:44:30with those canine teeth on the lower jaw
0:44:30 > 0:44:33being used like daggers against each other.
0:44:33 > 0:44:36And the females are scattering everywhere.
0:44:36 > 0:44:40The last thing they want is to get caught amongst this lot...
0:44:42 > 0:44:44..and neither do I!
0:44:45 > 0:44:48An even larger seal has joined the fight,
0:44:48 > 0:44:51forcing one male off the beach
0:44:51 > 0:44:54and then the other.
0:44:57 > 0:45:00This massive seal is a beachmaster,
0:45:00 > 0:45:03he controls an entire section of beach.
0:45:03 > 0:45:06The beachmaster seems to have seen off the challengers,
0:45:06 > 0:45:08they've both gone into the surf.
0:45:09 > 0:45:12The supergiant seal defeated both rivals,
0:45:12 > 0:45:15and by doing that has retained the right
0:45:15 > 0:45:17to mate with every female in his territory.
0:45:21 > 0:45:23He is the beachmaster
0:45:23 > 0:45:26and this is the reason these animals get to be so big.
0:45:27 > 0:45:32Very few seals ever get to be beachmasters, although plenty try.
0:45:34 > 0:45:37The stakes couldn't be higher.
0:45:37 > 0:45:41The winners might father 100 pups in a single season.
0:45:41 > 0:45:44The losers might die as virgins.
0:45:46 > 0:45:50Essentially, success, being able to pass on your genes,
0:45:50 > 0:45:54is all down to size, it's all about being a supergiant.
0:45:54 > 0:45:58The vast majority of pups born at Ano Nuevo
0:45:58 > 0:46:00have a beachmaster for a dad.
0:46:00 > 0:46:04It's no wonder they all grow up to become supergiants.
0:46:09 > 0:46:13I've seen how supergiants use their size to hunt prey,
0:46:13 > 0:46:18survive extremes, expand their territory and win mates.
0:46:21 > 0:46:25But there's one ultimate supergiant I want to find
0:46:25 > 0:46:27that dwarfs all the others.
0:46:33 > 0:46:36We couldn't go on a quest for giant animals
0:46:36 > 0:46:38without seeking out the largest ever known to have lived,
0:46:38 > 0:46:40the great whales.
0:46:48 > 0:46:50These are the largest animals on Earth,
0:46:50 > 0:46:53some are even heavier than the biggest of the dinosaurs.
0:46:56 > 0:46:58Most great whales are toothless,
0:46:58 > 0:47:02feeding by sieving tiny sea creatures from the ocean.
0:47:05 > 0:47:08But there's an exception.
0:47:08 > 0:47:12One of these leviathans is toothed and predatory.
0:47:16 > 0:47:19It's a monster that does battle with giant squid
0:47:19 > 0:47:22in the inky blackness of the deep ocean. The sperm whale.
0:47:23 > 0:47:27These are hunters of large fish, sharks
0:47:27 > 0:47:31and, as this footage shows, the legendary giant squid.
0:47:36 > 0:47:39Sperm whales can weigh 45 tonnes,
0:47:39 > 0:47:43and use their size to generate the loudest sound in the animal kingdom.
0:47:46 > 0:47:50I want to discover what they use this superpower for,
0:47:50 > 0:47:52and experience it for myself.
0:47:55 > 0:48:00The best place to do that is the island of Dominica, where the whales pass just off the coast.
0:48:02 > 0:48:04Here we go.
0:48:04 > 0:48:07We have blue skies, mirror-flat seas,
0:48:07 > 0:48:12this is just the perfect day for an encounter with a marine monster.
0:48:15 > 0:48:19We used to seek out sperm whales for all the wrong reasons.
0:48:23 > 0:48:28Over the last two centuries, we pulled around a million of them from the sea,
0:48:28 > 0:48:31hunting them for their valuable spermaceti oil
0:48:31 > 0:48:34which helped fuel the Industrial Revolution.
0:48:37 > 0:48:39Now, they're protected.
0:48:39 > 0:48:43Numbers are stable, and they're found in every ocean on Earth.
0:48:45 > 0:48:47But that doesn't mean they're easy to find.
0:48:50 > 0:48:52To narrow our search, we're going to try
0:48:52 > 0:48:55and track the whales using their own superpower.
0:49:02 > 0:49:06On the end of this pole is a highly-directional microphone,
0:49:06 > 0:49:10we put that into the water and we should be able to hear the sperm whale.
0:49:10 > 0:49:14Andrew Armour has worked with whales for over 20 years.
0:49:15 > 0:49:17He can pick out the faintest of calls.
0:49:17 > 0:49:18FAINT CLICKS
0:49:18 > 0:49:20Hear that?
0:49:20 > 0:49:21What do you hear?
0:49:21 > 0:49:23Sounds like whales.
0:49:23 > 0:49:26Their calls can travel over 30 miles,
0:49:26 > 0:49:30and there are several distinct types.
0:49:30 > 0:49:33I do hear it now, now that you've pointed it out.
0:49:33 > 0:49:37"Tik-tik-tik-tik-tik, tik-tik-tik-tik-tik..."
0:49:37 > 0:49:40This kind of call is known as "coda",
0:49:40 > 0:49:43and sperm whales use it for communication.
0:49:43 > 0:49:46So this is almost certainly a group.
0:49:54 > 0:49:56There she blows, Philbert!
0:49:56 > 0:50:01This is my chance to get up close to these giants.
0:50:10 > 0:50:11OK, get in now, get in now!
0:50:17 > 0:50:21I've joined a baby and an adult female.
0:50:29 > 0:50:34Female sperm whales live in family groups up to 20 strong.
0:50:40 > 0:50:43The rest of this pod could well be hunting far below us.
0:50:45 > 0:50:47Youngsters can't dive deep,
0:50:47 > 0:50:51so this baby-sitter has stayed at the surface.
0:50:51 > 0:50:55It could be Mum, an aunt or even Grandma.
0:50:58 > 0:51:00She's playing with me,
0:51:00 > 0:51:02mirroring my movements.
0:51:13 > 0:51:17As she dives, she swings past my cameraman.
0:51:22 > 0:51:26That tail has the force to power a giant,
0:51:26 > 0:51:28it could easily kill a human.
0:51:30 > 0:51:33Yet she takes care not to hit either of us.
0:51:36 > 0:51:38It's a remarkable display of agility.
0:51:48 > 0:51:53The whales are just as fascinated with me as I am with them.
0:51:53 > 0:51:56It's a far cry from the meetings between our species
0:51:56 > 0:51:58in the days of whaling.
0:52:06 > 0:52:09I am absolutely shaking like a leaf.
0:52:09 > 0:52:11She brought her calf right alongside us,
0:52:11 > 0:52:16span over onto her side so that she was looking directly in my eyes
0:52:16 > 0:52:18from no more than a couple of metres away
0:52:18 > 0:52:23and then she pirouetted like a ballerina and swept past me.
0:52:24 > 0:52:28But she made so sure that she didn't hit me.
0:52:36 > 0:52:39Back on land, I've got a chance to see how sperm whales
0:52:39 > 0:52:42generate their extraordinarily powerful calls.
0:52:50 > 0:52:55This is a cast of a skeleton of a small female sperm whale.
0:52:55 > 0:52:58I guess the thing that catches the attention is the lower jaw,
0:52:58 > 0:53:01lined with these curved, backwards-facing teeth.
0:53:01 > 0:53:06But weirdly, the predatory weapon of the sperm whale is up here.
0:53:09 > 0:53:13This is where the bulk of the head sits, and it is immense.
0:53:13 > 0:53:16It could make up as much as a third of the animal's body length.
0:53:16 > 0:53:22Almost all of this is filled with spermaceti, that waxy oily liquid.
0:53:22 > 0:53:25The sounds that the sperm whale generates are bizarrely created
0:53:25 > 0:53:29at the front of the nose, travel back through the spermaceti
0:53:29 > 0:53:32until they hit this portion of the skull,
0:53:32 > 0:53:35which is shaped like a satellite dish, a parabola.
0:53:35 > 0:53:39It focuses and intensifies the sounds as they pass back
0:53:39 > 0:53:43through the spermaceti, and then out at this end of the animal.
0:53:45 > 0:53:48This beam of sound bounces off objects in the water.
0:53:49 > 0:53:53By listening to the echoes, sperm whales build up
0:53:53 > 0:53:56a three-dimensional picture of their surroundings.
0:53:58 > 0:53:59Using this system,
0:53:59 > 0:54:03they can hunt in total darkness over 1,000 metres underwater.
0:54:05 > 0:54:08To feel the force of these sounds for myself,
0:54:08 > 0:54:10I'm heading back out to sea.
0:54:12 > 0:54:14There she blows, Philli!
0:54:14 > 0:54:1612.30!
0:54:19 > 0:54:22We have a mother and her calf approaching from this side,
0:54:22 > 0:54:23travelling very quickly.
0:54:25 > 0:54:27And three animals travelling from this side.
0:54:27 > 0:54:30It looks like their paths are going to converge
0:54:30 > 0:54:32right in front of us.
0:54:32 > 0:54:37It's possible this could be exactly what we've been waiting for.
0:54:37 > 0:54:40If it's a family group, there's likely to be a lot of communication.
0:54:41 > 0:54:45This is my chance to feel the power of sperm whale sonar.
0:54:54 > 0:54:57I've dropped right into the middle
0:54:57 > 0:54:59of a group of socialising sperm whales...
0:55:05 > 0:55:08..and the sound is overwhelming!
0:55:14 > 0:55:18The largest males can generate 230 decibels,
0:55:18 > 0:55:21far louder than a jet plane taking off.
0:55:31 > 0:55:34The whales seem to be scanning me, firing sonar at my body
0:55:34 > 0:55:37and visualising its shape by listening to the echoes.
0:55:43 > 0:55:47It's highly directional, as the barrel of the whale's head turns
0:55:47 > 0:55:51towards me, I can feel the sound resonating through my whole body.
0:55:57 > 0:55:59And she's giving me a good eyeballing.
0:56:11 > 0:56:14The biggest sperm whales can be 20 metres long
0:56:14 > 0:56:16and four times heavier than a fire engine.
0:56:21 > 0:56:24Physically, I have little in common with this supergiant,
0:56:24 > 0:56:28yet I feel closer to it than any of the others.
0:56:30 > 0:56:35We're both creatures with close family bonds,
0:56:35 > 0:56:37a real sense of curiosity...
0:56:39 > 0:56:42..and a desire to communicate.
0:56:59 > 0:57:02That was perfect!
0:57:02 > 0:57:04Absolutely mesmerising!
0:57:04 > 0:57:08That was exactly what we've come halfway round the world to find.
0:57:08 > 0:57:11The sound of the whales is deafening.
0:57:11 > 0:57:14But it is rather a mystical experience,
0:57:14 > 0:57:19kind of feeling like you're really in the whales' world.
0:57:19 > 0:57:21It's thought that sperm whales can use
0:57:21 > 0:57:24their most powerful pulses of sound as a weapon,
0:57:24 > 0:57:26stunning giant squid.
0:57:28 > 0:57:30Yet, rather than being hostile,
0:57:30 > 0:57:33this supergiant is the most gentle I've met.
0:57:40 > 0:57:41I think the sperm whale is,
0:57:41 > 0:57:44to me, the epitome of the supergiant animal,
0:57:44 > 0:57:47one that can do things we human beings can only dream of,
0:57:47 > 0:57:51and makes us realise quite how fragile we really are.
0:57:52 > 0:57:55These remarkable animals have overcome all the problems
0:57:55 > 0:58:00that size throws at them, in order to dominate their environments.
0:58:02 > 0:58:06But their future survival is far from certain.
0:58:06 > 0:58:10In today's world of shrinking habitats and dwindling resources,
0:58:10 > 0:58:15it's tougher than ever for giants to find space to live, and food to eat.
0:58:18 > 0:58:21Supergiant animals fill us with awe and wonder
0:58:21 > 0:58:24and remind us of everything that's special in the natural world.
0:58:24 > 0:58:26Everything that's worth saving.
0:58:37 > 0:58:41Subtitles by Red Bee Media Ltd