0:00:05 > 0:00:09We're living through the golden age of dinosaur discoveries.
0:00:10 > 0:00:12All over the world,
0:00:12 > 0:00:15a whole new generation of dinosaurs has been revealed.
0:00:17 > 0:00:19From the biggest giants
0:00:19 > 0:00:21and the deadliest killers
0:00:21 > 0:00:23to the weird and the wonderful.
0:00:32 > 0:00:35From the Arctic to Africa,
0:00:35 > 0:00:39from South America to Asia.
0:00:43 > 0:00:46In just the last few years,
0:00:46 > 0:00:49we have uncovered extraordinary fossils,
0:00:49 > 0:00:51exquisitely preserved and tantalisingly intact.
0:00:51 > 0:00:56Combined with the latest imaging technology,
0:00:56 > 0:00:58we have been able to probe deeper
0:00:58 > 0:01:01and reveal more than ever before.
0:01:04 > 0:01:08It gives us our first truly global view
0:01:08 > 0:01:10of these incredible animals.
0:01:25 > 0:01:29In this programme we examine the new giants -
0:01:29 > 0:01:32the heavyweights of the dinosaur world.
0:01:32 > 0:01:34It's only in recent years
0:01:34 > 0:01:38that we have unearthed the biggest dinosaurs that ever lived.
0:01:38 > 0:01:42Animals on such a huge scale it is difficult to comprehend.
0:01:42 > 0:01:47Just how and why did these titans grow so massive?
0:01:48 > 0:01:52And could any animal attack such a huge beast?
0:01:53 > 0:01:57One of these new giants has eclipsed all others.
0:01:57 > 0:02:00At 35 metres, it was as long as Diplodocus.
0:02:00 > 0:02:05Yet this dinosaur was seven times as heavy.
0:02:09 > 0:02:13The first glimpse of this new giant was made in the 1990s
0:02:13 > 0:02:15during a dig in Argentina.
0:02:18 > 0:02:22In Patagonia, a fossil was pulled from the ground.
0:02:22 > 0:02:27It was a single vertebra, but it was as tall as a human being.
0:02:28 > 0:02:31Other bones followed.
0:02:31 > 0:02:34They belonged to the biggest dinosaur
0:02:34 > 0:02:36ever known to have walked the Earth.
0:02:38 > 0:02:43It lived in South America 95 million years ago.
0:02:45 > 0:02:48In a world very different from our own -
0:02:48 > 0:02:52a world that is only now giving up its secrets.
0:03:05 > 0:03:08The start of a new life.
0:03:14 > 0:03:18But on these plains, danger is never far away.
0:03:20 > 0:03:24This is a chaoyangopterid pterosaur,
0:03:24 > 0:03:27attracted to the easy prey of a nest site.
0:04:12 > 0:04:14Throughout the late 1990s,
0:04:14 > 0:04:18extraordinary dinosaurs were uncovered in Argentina.
0:04:18 > 0:04:25At one location, a nest site was found, so full of dinosaur eggs
0:04:25 > 0:04:29that they could barely avoid crushing them underfoot.
0:04:29 > 0:04:34Some eggs even contained exquisitely preserved dinosaur embryos.
0:04:36 > 0:04:38Then, in 1999, at the same nest site,
0:04:38 > 0:04:42a complete adult dinosaur skeleton was uncovered.
0:04:43 > 0:04:46It appeared they'd found the parent.
0:05:09 > 0:05:11But first impressions can be deceptive.
0:05:11 > 0:05:14This isn't the parent.
0:05:14 > 0:05:17This is a Skorpiovenator -
0:05:17 > 0:05:18a predator.
0:05:22 > 0:05:26The skeleton found at the nest site was almost certainly a nest raider,
0:05:26 > 0:05:28preying on the hatchlings.
0:05:48 > 0:05:50The hatchlings' real parent,
0:05:50 > 0:05:54and the owner of the enormous vertebra is Argentinosaurus.
0:05:58 > 0:06:02A plant-eating giant that dwarfs everything around it.
0:06:11 > 0:06:13From the bones that were found,
0:06:13 > 0:06:16we've calculated that Argentinosaurus
0:06:16 > 0:06:19was a colossal 35 metres long,
0:06:19 > 0:06:22and weighed as much as 75 tonnes.
0:06:28 > 0:06:34When born, the hatchlings themselves weigh a paltry 5kg
0:06:34 > 0:06:37and need to fend for themselves immediately.
0:06:49 > 0:06:53From studying the embryos, and looking at the bones of the adults,
0:06:53 > 0:06:57we know that the growth of these giants was phenomenal.
0:06:58 > 0:07:00Over 40 years,
0:07:00 > 0:07:05they grow from 5kg to an astonishing 75,000kg.
0:07:06 > 0:07:12At their peak, it's been calculated they grow up to 40kg every day.
0:07:15 > 0:07:19The dinosaur embryos are so well preserved
0:07:19 > 0:07:22we can see they already have their teeth,
0:07:22 > 0:07:25in preparation for a lifetime of eating.
0:07:41 > 0:07:45But becoming a giant takes more than simply turning tonnes of food
0:07:45 > 0:07:46into muscle.
0:07:49 > 0:07:52It's about the success and survival of a species
0:07:52 > 0:07:53over millions of years.
0:07:58 > 0:08:02One way to increase the chances of survival
0:08:02 > 0:08:04is by having lots of offspring.
0:08:04 > 0:08:08And the best way to do that is by laying eggs.
0:08:15 > 0:08:17Lots of them.
0:08:19 > 0:08:23The nest site in Patagonia stretches for an astonishing 15km
0:08:23 > 0:08:27and contains tens of thousands of eggs.
0:08:29 > 0:08:33And the site was used continuously for hundreds of thousands of years.
0:08:36 > 0:08:42For killers like Skorpiovenator, the nest site provides a feast.
0:08:45 > 0:08:46But, with thousands of hatchlings,
0:08:46 > 0:08:51they have little impact on the success of the species.
0:08:53 > 0:08:55And pose no threat to the adults.
0:08:59 > 0:09:03But, wherever we find giant plant-eaters...
0:09:05 > 0:09:09..there is always a giant killer lurking nearby.
0:09:15 > 0:09:20And, sure enough, another startling discovery was made in Argentina.
0:09:20 > 0:09:24In the same region, a nearly complete skeleton
0:09:24 > 0:09:28of an enormous predator was unearthed amazingly well preserved.
0:09:30 > 0:09:34The skull alone was over 1.5 metres long.
0:09:34 > 0:09:37And when a second, even larger, specimen was found,
0:09:37 > 0:09:41it became clear that this was bigger than any predator
0:09:41 > 0:09:43that had been found before.
0:09:44 > 0:09:45Bigger than T Rex.
0:09:51 > 0:09:55It was clear that giant predators roamed South America as well.
0:09:55 > 0:10:00And it appeared that Argentinosaurus may have met its match.
0:10:05 > 0:10:09In fact, wherever giant plant eaters have been discovered,
0:10:09 > 0:10:14it appears a giant predator lived alongside them.
0:10:14 > 0:10:17From America, to Europe and Asia,
0:10:17 > 0:10:20we see the same relationship repeated.
0:10:23 > 0:10:27But there was one place on earth that remained a mystery.
0:10:27 > 0:10:31For decades, Africa was the forgotten continent,
0:10:31 > 0:10:35a huge gap in our understanding of planet dinosaur.
0:10:35 > 0:10:40Then, in 2000, a cluster of bones was unearthed in North Africa.
0:10:42 > 0:10:46The bones were huge - one single leg bone was as tall as a human.
0:10:49 > 0:10:53It seemed this, too, was a land of giants.
0:10:53 > 0:10:55And that could only mean one thing.
0:10:55 > 0:10:57There must also be a giant killer.
0:11:03 > 0:11:0895 million years ago, this was a dry and difficult place to survive.
0:11:08 > 0:11:12Food and water were hard to come by and often only found in one place -
0:11:12 > 0:11:19along the banks of a river that has earned the name River of Giants.
0:11:20 > 0:11:24This is Paralititan, a 45-tonne animal...
0:11:26 > 0:11:30..and the undisputed heavyweight here.
0:11:34 > 0:11:37For an animal this size, it's not easy to keep cool,
0:11:37 > 0:11:40so being near water is vital.
0:11:53 > 0:11:56But rivers are dangerous places.
0:12:18 > 0:12:23This is not a good place for a young animal to get stuck.
0:12:30 > 0:12:34And it's not just because of these crocodiles.
0:12:37 > 0:12:40This river holds much, much bigger threats.
0:12:57 > 0:12:59It may look familiar...
0:13:01 > 0:13:05but this was no ordinary crocodile.
0:13:05 > 0:13:07With a skull nearly two metres long,
0:13:07 > 0:13:11it's more than twice the size of any modern croc.
0:13:13 > 0:13:15This was Sarcosuchus.
0:13:19 > 0:13:21Weighing as much as eight tonnes,
0:13:21 > 0:13:24it's the undisputed king of crocodiles.
0:13:32 > 0:13:34A cold-blooded killer.
0:13:34 > 0:13:39And if it can drag its prey into the water and drown it, even better.
0:13:47 > 0:13:49But, even for a deadly predator like this,
0:13:49 > 0:13:52the River of Giants holds dangers.
0:14:06 > 0:14:09Across the world from Africa to Argentina,
0:14:09 > 0:14:13giant sauropods roamed far and wide.
0:14:13 > 0:14:17This herd of Argentinosaurus are now on the move,
0:14:17 > 0:14:21travelling across a swamp covered with volcanic ash.
0:14:27 > 0:14:31It's a dangerous place to be if you're living in the shadows.
0:14:45 > 0:14:47These giants are so massive
0:14:47 > 0:14:50they've turned the sand beneath their feet into quicksand,
0:14:50 > 0:14:53creating death traps with every step.
0:15:01 > 0:15:05It's a danger that was graphically revealed in 2010,
0:15:05 > 0:15:09when an astonishing set of footprints were unearthed.
0:15:09 > 0:15:12Footprints that contained a deadly secret.
0:15:14 > 0:15:17After months of painstaking examination,
0:15:17 > 0:15:20some of the fossil footprints were found to contain
0:15:20 > 0:15:22bones of other animals.
0:15:22 > 0:15:26One exposed the bodies of two mammals, ten small dinosaurs,
0:15:26 > 0:15:28two crocodiles and a turtle.
0:15:30 > 0:15:34In total, 18 animals were buried within a single step.
0:15:36 > 0:15:38But becoming this big is not easy.
0:15:38 > 0:15:41It requires some serious eating.
0:15:41 > 0:15:45Argentinosaurus weighed around 75 tonnes.
0:15:45 > 0:15:51A six-tonne African elephant eats for 18 hours a day to keep going.
0:15:51 > 0:15:55Argentinosaurus weighs more than ten times as much.
0:15:55 > 0:15:57So how did they get enough food?
0:16:00 > 0:16:04They turned themselves into the most efficient eating machines
0:16:04 > 0:16:07the world has ever known.
0:16:07 > 0:16:10Everything about them is designed to get the most food in
0:16:10 > 0:16:13and the most calories out, with the least effort.
0:16:15 > 0:16:19Their long necks give them access to more food without moving.
0:16:19 > 0:16:22But the way they eat is the crucial bit.
0:16:23 > 0:16:27These giants don't waste time chewing.
0:16:27 > 0:16:30They rip and gulp down leaves whole,
0:16:30 > 0:16:33which are digested by bacteria in its massive gut.
0:16:33 > 0:16:37Not chewing means it doesn't need a big, heavy head
0:16:37 > 0:16:39with big teeth and muscular jaws,
0:16:39 > 0:16:43which also means its neck can grow so long,
0:16:43 > 0:16:46able to reach food no other animal can reach.
0:16:52 > 0:16:57Being so big means you're off the menu for most predators.
0:16:58 > 0:17:02Here, there's a killer in a completely different league.
0:17:07 > 0:17:11Over ten metres long and weighing around four tonnes,
0:17:11 > 0:17:15this is Mapusaurus. A newly discovered killer on the block.
0:17:44 > 0:17:49On its own, even it is not a match for a fully grown Argentinosaurus.
0:17:56 > 0:17:59But this giant killer is not alone.
0:18:06 > 0:18:10For years, it was thought that an adult Argentinosaurus would be
0:18:10 > 0:18:13too big for any predator to tackle.
0:18:16 > 0:18:20But in 2006, a new discovery suddenly made even
0:18:20 > 0:18:24the biggest of dinosaurs a lot more vulnerable. As they dug into
0:18:24 > 0:18:29the Argentinean dirt, they didn't just find one predator buried here.
0:18:29 > 0:18:33The skeletons of at least seven Mapusaurus of different ages
0:18:33 > 0:18:38and sizes were found together. It suggested that this was a group.
0:18:45 > 0:18:48A giant killer that appears to hunt in gangs.
0:18:51 > 0:18:56And more than capable of taking on the very biggest dinosaurs.
0:19:11 > 0:19:15Not even a fully grown Argentinosaurus
0:19:15 > 0:19:17is safe from this group.
0:19:19 > 0:19:21The best defence is their sheer size.
0:19:50 > 0:19:56Mapusaurus's teeth are perfectly designed, like blades,
0:19:56 > 0:19:58to slice off chunks of flesh.
0:20:01 > 0:20:04With prey so large, a single bite isn't always fatal.
0:20:04 > 0:20:08It appears Mapusaurus could just snack,
0:20:09 > 0:20:12feeding from its victim without actually killing it.
0:20:20 > 0:20:25The victim surviving to provide more food at a later date.
0:20:35 > 0:20:37But even in a group,
0:20:37 > 0:20:40these giant killers are never far away from danger.
0:20:45 > 0:20:49Attacking an animal more than ten times your weight
0:20:49 > 0:20:50carries grave risks.
0:21:24 > 0:21:27Even with the threat of predators hunting in gangs,
0:21:27 > 0:21:31the phenomenal size of these giants would usually keep them safe.
0:21:32 > 0:21:35But a giant needs to grow.
0:21:37 > 0:21:41It's the younger, smaller animals that are in greatest danger from
0:21:41 > 0:21:44giant predators like Sarcosuchus.
0:21:44 > 0:21:47And here in Africa there is nowhere to hide.
0:22:22 > 0:22:26Things are about to get even worse for the young Paralititan.
0:22:28 > 0:22:31Around the river of giants, there is another killer.
0:22:34 > 0:22:39Carcharodontosaurus. A predator always looks for the easiest kill,
0:22:39 > 0:22:45the weak, injured or young. The Paralititan is all three.
0:23:05 > 0:23:10In such a deadly game of tug of war there can only be one winner.
0:23:34 > 0:23:36But the kill is still not certain.
0:23:36 > 0:23:39Carcharodontosaurus can tackle this youngster,
0:23:39 > 0:23:43but a herd of 45-tonne adults is another matter.
0:24:05 > 0:24:10Injured but alive, this youngster has a lucky escape.
0:24:10 > 0:24:15Encounters like this have left tantalising clues behind.
0:24:15 > 0:24:17Amongst the bones of a Paralititan,
0:24:17 > 0:24:20we have found a Carcharodontosaurus tooth suggesting
0:24:20 > 0:24:23a predator-prey relationship.
0:24:23 > 0:24:26They complete a global picture,
0:24:26 > 0:24:28a pattern that is repeated across the world.
0:24:28 > 0:24:32In Asia, we find Mamenchisaurus and Sinraptor.
0:24:32 > 0:24:38In North America, Diplodocus and Allosaurus and now Africa.
0:24:39 > 0:24:43For every giant plant eater we find a giant predator
0:24:43 > 0:24:47living side by side. And it's in South America
0:24:47 > 0:24:49where we have the biggest of all.
0:24:49 > 0:24:52Argentinosaurus and Mapusaurus.
0:24:52 > 0:24:57Two giants whose fates appear to be inextricably linked.
0:25:15 > 0:25:19This Argentinosaurus wounded by a gang of mapusaurs
0:25:19 > 0:25:22has succumbed to its wounds.
0:25:28 > 0:25:31Out on the plain, other keen-eyed predators are quick to spot
0:25:31 > 0:25:33a stricken animal.
0:25:47 > 0:25:50It's a prize worth waiting for.
0:25:50 > 0:25:53And attracts carnivores from miles around.
0:26:25 > 0:26:28Mapusaurus are not only hunters.
0:26:28 > 0:26:30Like virtually every carnivore today,
0:26:30 > 0:26:34scavenged prey plays a huge part in their diet.
0:26:47 > 0:26:51We know enough about the biology of giant sauropods
0:26:51 > 0:26:56to estimate of this 70-tonne animal, 11 tonnes is bone,
0:26:56 > 0:27:03three and a half tonnes blood, four tonnes is hide and skin,
0:27:03 > 0:27:0815 tonnes fat and 39 tonnes is meat.
0:27:08 > 0:27:13Enough to feed a whole ecosystem for days.
0:27:33 > 0:27:38Mapusaurus was reliant on the giant sauropods in life and death.
0:27:39 > 0:27:42When the Argentinosaurus disappeared from South America
0:27:42 > 0:27:4493 million years ago,
0:27:44 > 0:27:48so did the giant predator Mapusaurus.
0:27:48 > 0:27:52It was the same story in Africa - when Paralititan vanished,
0:27:52 > 0:27:55Caracharodontosaurus followed.
0:27:55 > 0:27:58It appears that these extinctions were linked,
0:27:58 > 0:28:02and this story is repeated time and again.
0:28:02 > 0:28:05When the giant sauropods died out,
0:28:05 > 0:28:08the giant predators lost their main food supply
0:28:08 > 0:28:10and they too were doomed.
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