0:00:04 > 0:00:06THEY GROWL
0:00:06 > 0:00:10We're living through THE golden age of dinosaur discoveries.
0:00:12 > 0:00:15All over the world, a whole new generation
0:00:15 > 0:00:17of dinosaurs has been revealed.
0:00:18 > 0:00:20From the biggest giants...
0:00:20 > 0:00:22and the deadliest killers...
0:00:22 > 0:00:24to the weird and wonderful.
0:00:33 > 0:00:37From the Arctic to Africa.
0:00:37 > 0:00:39From South America to Asia.
0:00:45 > 0:00:47In just the last few years,
0:00:47 > 0:00:50we have uncovered the most extraordinary fossils,
0:00:50 > 0:00:53exquisitely preserved and tantalisingly intact.
0:00:55 > 0:00:58Combined with the latest imaging technology,
0:00:58 > 0:01:02we have been able to probe deeper and reveal more than ever before.
0:01:06 > 0:01:13It gives us our first truly global view of these incredible animals.
0:01:28 > 0:01:32In this programme, we're exploring the lost world of Africa.
0:01:33 > 0:01:37For almost 100 years, this was a forgotten land.
0:01:39 > 0:01:41Now, new discoveries have revealed
0:01:41 > 0:01:44some of the most spectacular dinosaurs ever found.
0:01:44 > 0:01:46Two giant killers,
0:01:46 > 0:01:49both bigger than T Rex,
0:01:49 > 0:01:52both living in the same place.
0:01:55 > 0:01:57IT ROARS
0:02:01 > 0:02:03One of these killers, more than any,
0:02:03 > 0:02:05has captured the imagination.
0:02:07 > 0:02:11A bizarre killer that we've only just managed to reconstruct,
0:02:11 > 0:02:13in the last few years.
0:02:16 > 0:02:19The story begins in Egypt, in 1912,
0:02:19 > 0:02:23when fragments of a giant dinosaur were discovered.
0:02:25 > 0:02:29A predator with two-metre-long spines rising over its back.
0:02:30 > 0:02:32It was unlike anything seen before.
0:02:34 > 0:02:38It was only in 2005, when a complete upper jaw was found,
0:02:38 > 0:02:41that we could accurately reconstruct this bizarre creature.
0:02:43 > 0:02:45With a skull almost two metres long,
0:02:45 > 0:02:49this dinosaur was a colossal 17 metres
0:02:49 > 0:02:51from nose to tail -
0:02:51 > 0:02:54four metres longer than T Rex.
0:02:58 > 0:03:01The reign of the dinosaurs began
0:03:01 > 0:03:03almost 250 million years ago.
0:03:05 > 0:03:06But this killer didn't appear
0:03:06 > 0:03:10until a time known as the Mid-Cretaceous.
0:03:10 > 0:03:1595 million years ago, its home in north Africa
0:03:15 > 0:03:19was a desert surrounding a vast system of rivers and swamps.
0:03:24 > 0:03:27The swamps are refuges for many large dinosaurs,
0:03:27 > 0:03:30like the duck-billed Ouranosaurus.
0:03:30 > 0:03:32IT BARKS
0:03:33 > 0:03:35IT BELLOWS
0:03:43 > 0:03:46They're also the hunting grounds for a killer.
0:03:48 > 0:03:50IT BELLOWS
0:03:54 > 0:03:56IT ROARS
0:03:56 > 0:03:59IT SNIFFS AND GRUNTS
0:04:03 > 0:04:05IT SNIFFS
0:04:05 > 0:04:07IT BELLOWS
0:04:07 > 0:04:11At seven metres and three tonnes, Ouranosaurs are big...
0:04:18 > 0:04:22..but easily within the scope of a large predator.
0:04:30 > 0:04:34IT BELLOWS
0:04:35 > 0:04:37IT GROWLS
0:05:07 > 0:05:09WATER SPLASHES
0:05:10 > 0:05:12IT BELLOWS
0:05:15 > 0:05:17IT SNIFFS
0:05:22 > 0:05:24Spinosaurus.
0:05:26 > 0:05:30At 17 metres, the biggest killer ever to walk the Earth.
0:05:32 > 0:05:34An 11-tonne colossus.
0:05:44 > 0:05:47IT RASPS AND GROWLS
0:05:54 > 0:05:56However, for the time being,
0:05:56 > 0:05:59these Ouranosaurs are off this killer's menu.
0:06:07 > 0:06:11Spinosaurus is part of a family of dinosaurs
0:06:11 > 0:06:14that are relatively newly-discovered.
0:06:14 > 0:06:17Recent finds have shown that this strange group
0:06:17 > 0:06:20lived from South America, through Europe, to Asia.
0:06:22 > 0:06:27But the last and biggest of all came from north Africa.
0:06:27 > 0:06:28Spinosaurus itself.
0:06:30 > 0:06:36In 2010, analysis of their bones and teeth revealed something surprising.
0:06:36 > 0:06:41Chemical traces found in the fossils suggested the Spinosaurus lived
0:06:41 > 0:06:45more like a crocodile than other land-based dinosaurs.
0:06:46 > 0:06:51It showed that they spent a large part of their lives in water.
0:06:55 > 0:06:56IT BARKS
0:07:06 > 0:07:11Spinosaurus is a predator, but one that hunts in water.
0:07:13 > 0:07:16It's ichthyophagous - a fish-eater.
0:07:21 > 0:07:23This is Onchopristis.
0:07:28 > 0:07:31An eight-metre-long giant swordfish,
0:07:31 > 0:07:32similar to those alive today.
0:07:34 > 0:07:37The saw-like rostrum is lined with lethal barbs,
0:07:37 > 0:07:40and is in itself up to 2.5 metres in length.
0:07:42 > 0:07:46It's thought they migrated into freshwater rivers to breed,
0:07:46 > 0:07:49where the young may be safer,
0:07:49 > 0:07:52but the adults are exposed to new threats.
0:07:59 > 0:08:01With their breeding season at its height,
0:08:01 > 0:08:06these rivers are filled with Onchopristis.
0:08:06 > 0:08:09It's the perfect hunting opportunity for Spinosaurus.
0:08:40 > 0:08:44Spinosaurus's conical teeth evolved to grip prey
0:08:44 > 0:08:47rather than tear off flesh.
0:08:47 > 0:08:50For that, it needs powerful arms and claws.
0:08:50 > 0:08:52IT GROWLS
0:08:58 > 0:09:00GROWLING
0:09:09 > 0:09:14With prey plentiful, Spinosaurus can afford to be wasteful.
0:09:14 > 0:09:17A fact which other dinosaurs take full advantage of.
0:09:20 > 0:09:23Rugops, an eight-metre carnivore.
0:09:25 > 0:09:27Anywhere else, it might dominate.
0:09:29 > 0:09:32But here, it is dwarfed by Spinosaurus.
0:09:42 > 0:09:46Spinosaurus is unique, with long, narrow jaws
0:09:46 > 0:09:49and nostrils set high on its head.
0:09:49 > 0:09:51Its teeth were straight and conical.
0:09:51 > 0:09:54They gave us a clue as to how it killed.
0:09:56 > 0:09:58More evidence came in 2008,
0:09:58 > 0:10:01when Spinosaurus' skull was put through a CT scanner.
0:10:03 > 0:10:07It revealed a curious pattern of holes and sinuses in the snout
0:10:07 > 0:10:10that looked just like those of crocodiles.
0:10:11 > 0:10:15It's thought these contained pressure sensors,
0:10:15 > 0:10:19sensors that, like a crocodile, can detect prey,
0:10:19 > 0:10:22making it perfectly adapted to hunting in water.
0:10:28 > 0:10:33This discovery gives us our best evidence of exactly how it hunted.
0:10:35 > 0:10:39Able to hold its snout in the water because of its high nostrils,
0:10:39 > 0:10:42it can strike without even seeing its prey.
0:10:46 > 0:10:48GROWLING
0:11:04 > 0:11:06IT GRUNTS
0:11:12 > 0:11:17The ever-attendant Rugops has a weak jaw and skull. It's no killer.
0:11:19 > 0:11:22It is a natural-born scavenger,
0:11:22 > 0:11:26living off the scraps of this highly-efficient predator.
0:11:35 > 0:11:38We can assume so much about the diet of Spinosaurus
0:11:38 > 0:11:41because its fossilised teeth are commonly found
0:11:41 > 0:11:44with the remains of the giant sawfish.
0:11:44 > 0:11:49More recent discoveries appear to provide even more direct evidence.
0:11:50 > 0:11:54In 2005, a Spinosaur fossil was found with a sawfish vertebrae
0:11:54 > 0:11:56stuck in a tooth socket.
0:11:58 > 0:12:00Another, discovered in 2008,
0:12:00 > 0:12:05had a fragment of a sawfish barb apparently embedded in its jaw.
0:12:05 > 0:12:09They suggested a clear predator-prey relationship.
0:12:13 > 0:12:16Spinosaurus is the region's biggest killer
0:12:16 > 0:12:19because it can exploit an environment so successfully.
0:12:19 > 0:12:22A dinosaur at home in water.
0:12:22 > 0:12:27For a time, it lived with little threat from other dinosaurs
0:12:27 > 0:12:30and the species evolved into a 17-metre giant.
0:12:37 > 0:12:42But Spinosaurus wasn't the only giant predator which thrived here.
0:12:45 > 0:12:50Carcharodontosaurus. Land-based killer.
0:12:52 > 0:12:56A meat-eater. A carnosaur.
0:12:57 > 0:13:00A cousin of Allosaurus, but four times bigger.
0:13:01 > 0:13:05With serrated teeth 16 centimetres long,
0:13:05 > 0:13:08Carcharodontosaurus was a giant killer.
0:13:10 > 0:13:13Up to 13 metres long and weighing around seven tonnes.
0:13:14 > 0:13:18Like Spinosaurus, it too was bigger than T Rex.
0:13:19 > 0:13:23Big predators need big hunting ranges.
0:13:23 > 0:13:30Carcharodontosaurus may have needed up to 500 square kilometres each,
0:13:30 > 0:13:34making competition for the best hunting grounds intense.
0:13:35 > 0:13:37IT ROARS
0:13:41 > 0:13:44These young, male Carcharodontosaurus
0:13:44 > 0:13:48both want supremacy over this territory.
0:13:48 > 0:13:52Dominating the land is the key to survival for these killers.
0:13:52 > 0:13:56That can mean a fight to the death.
0:13:56 > 0:13:57THEY GROWL AND ROAR
0:14:11 > 0:14:12THEY PANT AND GROWL
0:14:56 > 0:14:57THEY GRUNT AND SNORT
0:14:59 > 0:15:00IT ROARS
0:15:04 > 0:15:06The evidence of in-fighting
0:15:06 > 0:15:09between carnivores of the same species is dramatic.
0:15:11 > 0:15:13Forensic examinations of fossils has uncovered injuries
0:15:13 > 0:15:17on the skull bones of many large carnivores.
0:15:17 > 0:15:20Tooth puncture marks and gouges are remarkably common.
0:15:21 > 0:15:27Such violent head- and face-biting is thought likely to be territorial.
0:15:30 > 0:15:33With so much to gain, fights over prime hunting territory
0:15:33 > 0:15:35would be commonplace.
0:15:41 > 0:15:43For this victorious Carcharodontosaurus,
0:15:43 > 0:15:47the prize is the hunting rights to these Ouranosaurs.
0:15:48 > 0:15:52Not an easy prey to catch, even for the fastest of predators.
0:15:56 > 0:16:00But we think Carcharodontosaurus has a hidden advantage.
0:16:00 > 0:16:03In 2008, detailed bone analysis
0:16:03 > 0:16:07suggested these dinosaurs employed a system of air sacs.
0:16:08 > 0:16:10Air sacs are used in breathing.
0:16:12 > 0:16:16They ensure that oxygen-rich air flows continually through the lungs
0:16:16 > 0:16:18when breathing in and out.
0:16:18 > 0:16:23It's a very efficient system, similar to that of birds.
0:16:23 > 0:16:27It implied that dinosaurs like Carcharodontosaurus
0:16:27 > 0:16:29were highly-active hunters.
0:16:29 > 0:16:32And they needed to be.
0:16:32 > 0:16:35It's reckoned that a dinosaur of this size would need to eat
0:16:35 > 0:16:39a minimum of 60 kilos of meat every day simply to survive.
0:16:47 > 0:16:50Big hunters rely on ambushing their prey.
0:16:58 > 0:17:01Closing as much distance between it and its chosen victim.
0:17:19 > 0:17:21HONKING
0:17:37 > 0:17:39SQUEALING, GROWLING
0:17:54 > 0:17:55IT MOANS
0:17:55 > 0:17:56LOW GROWLING
0:17:58 > 0:18:02This Carcharodontosaurus doesn't waste energy
0:18:02 > 0:18:04chasing the injured animal.
0:18:08 > 0:18:13Its initial attack has critically wounded the Ouranosaurus.
0:18:13 > 0:18:16Now, it simply needs to follow and wait.
0:18:32 > 0:18:35PANTING
0:18:53 > 0:18:56Carcharodontosaurus were deadly killers,
0:18:56 > 0:18:59but not in the way you might expect.
0:18:59 > 0:19:02Its skull was relatively weak.
0:19:04 > 0:19:05And computer analysis has shown
0:19:05 > 0:19:08that they're unlikely to be strong enough
0:19:08 > 0:19:09to hold onto struggling prey.
0:19:11 > 0:19:14Their teeth were thin, like knives,
0:19:14 > 0:19:16too weak to bite easily through bone.
0:19:17 > 0:19:22But they were sharp, with deadly serrations, just like a shark's.
0:19:24 > 0:19:29The very name Carcharodontosaurus means "sharp-toothed lizard".
0:19:30 > 0:19:33We think it used its skull and teeth
0:19:33 > 0:19:35to slash deep into the flesh of its prey,
0:19:35 > 0:19:39causing massive injury and blood loss.
0:19:48 > 0:19:51Delivered at speed, such an attack could kill
0:19:51 > 0:19:54without the need for an intense struggle.
0:19:57 > 0:19:59It's an efficient killing method
0:19:59 > 0:20:03and one that's perfectly suited to this environment.
0:20:03 > 0:20:07But success can look very different when a season changes.
0:20:09 > 0:20:13For a time, Cretaceous north Africa had two deadly killers.
0:20:13 > 0:20:16By exploiting different environments,
0:20:16 > 0:20:19they didn't compete and could coexist,
0:20:19 > 0:20:25dominating their chosen habitats. Spinosaurus was a specialist.
0:20:25 > 0:20:27But this came with risks.
0:20:27 > 0:20:32Small environmental changes can make it vulnerable.
0:20:37 > 0:20:40And this area is prone to seasonal droughts.
0:20:58 > 0:20:59When the river is dry,
0:20:59 > 0:21:02Spinosaurus' usual food supply has disappeared.
0:21:06 > 0:21:09Other animals retreat to a few remaining pools.
0:21:11 > 0:21:13Some, the Spinosaurus would do well to be wary of.
0:21:22 > 0:21:25The smaller crocs aren't the problem.
0:21:27 > 0:21:31Sarcosuchus a giant 12-metre crocodile.
0:21:31 > 0:21:33IT ROARS
0:21:50 > 0:21:53Reptiles like these can survive droughts
0:21:53 > 0:21:58by effectively hibernating during times of hardship.
0:21:58 > 0:22:00Spinosaurus can't.
0:22:00 > 0:22:02As an active hunter,
0:22:02 > 0:22:05its metabolism demands a regular supply of food.
0:22:06 > 0:22:11Although it is a specialist, it isn't confined to the rivers.
0:22:11 > 0:22:15In tough times, it too can hunt on land.
0:22:15 > 0:22:17SQUAWKING
0:22:20 > 0:22:22IT BARKS
0:22:22 > 0:22:24SQUAWKING
0:22:37 > 0:22:39ROARING
0:22:42 > 0:22:44SQUEALING
0:22:50 > 0:22:52IT GROWLS
0:22:54 > 0:22:57Spinosaur fossils from other parts of the world
0:22:57 > 0:22:59have given us more details about their diets.
0:23:02 > 0:23:06In 2004, a dramatic fossil was recovered from Brazil.
0:23:08 > 0:23:10Part of the neck of a Pterosaur.
0:23:13 > 0:23:16Embedded within one of the vertebrae was a tooth.
0:23:19 > 0:23:22It was the unmistakable shape of a Spinosaur tooth.
0:23:25 > 0:23:28The stomach contents of another Spinosaur, Baryonyx,
0:23:28 > 0:23:33from England, was found to contain some bones of a juvenile Iguanodon,
0:23:33 > 0:23:35a plant-eating dinosaur.
0:23:35 > 0:23:37In spite of their specialisation,
0:23:37 > 0:23:41clearly Spinosaurs weren't exclusively fish-eaters.
0:23:46 > 0:23:49But hunting and catching prey isn't easy.
0:23:49 > 0:23:52Particularly when they're already alert.
0:24:10 > 0:24:13IT SNIFFS
0:24:19 > 0:24:21Hunting on land,
0:24:21 > 0:24:24Spinosaurus is also forced into direct competition
0:24:24 > 0:24:28with any large predators living in the same environment.
0:24:33 > 0:24:36And here, that can only mean one animal...
0:24:41 > 0:24:43..Carcharodontosaurus.
0:24:50 > 0:24:53GROWLING
0:25:00 > 0:25:02IT GROWLS
0:25:02 > 0:25:05GROWLING
0:25:07 > 0:25:10Contests over carcasses are common.
0:25:11 > 0:25:15But outcomes of such fights are far from guaranteed.
0:25:15 > 0:25:19Risk of injury for big animals is acute.
0:25:22 > 0:25:26Modern Komodo dragons are often killed in fights over carcasses.
0:25:29 > 0:25:31ROARING, GROWLING
0:25:31 > 0:25:33More than three metres longer,
0:25:33 > 0:25:36Spinosaurus has size and power on its side.
0:25:38 > 0:25:41ROARING, GROWLING
0:25:45 > 0:25:48But Carcharodontosaurus has the more lethal bite.
0:25:49 > 0:25:51SHRIEKING
0:25:55 > 0:25:57IT GROWLS
0:26:03 > 0:26:06This time, the Spinosaurus triumphed.
0:26:08 > 0:26:11But the balance of power between these two deadly killers
0:26:11 > 0:26:12is a precarious one.
0:26:16 > 0:26:18LOW GROWLING
0:26:23 > 0:26:27In 2008, a Spinosaurus vertebra was recovered.
0:26:29 > 0:26:33Part of the tall, neural spine of the bone was broken off.
0:26:34 > 0:26:37It appeared to have been bitten in half.
0:26:39 > 0:26:40It's been suggested
0:26:40 > 0:26:43that the bite was inflicted by Carcharodontosaurus.
0:26:47 > 0:26:51Spinosaurus was the last and the largest
0:26:51 > 0:26:53of the fish-eating dinosaurs.
0:26:53 > 0:26:58But ultimately, these specialists were doomed.
0:26:58 > 0:27:02Something way beyond their control caused their downfall.
0:27:02 > 0:27:0794 million years ago, the climate changed.
0:27:07 > 0:27:10Global sea levels began to rise.
0:27:10 > 0:27:14The swamps and rivers that Spinosaurus thrived in
0:27:14 > 0:27:15gradually were lost.
0:27:17 > 0:27:18With their loss,
0:27:18 > 0:27:22Spinosaurus's specialism became a vulnerability.
0:27:25 > 0:27:26And the biggest predator
0:27:26 > 0:27:29ever known to have walked the Earth disappeared.
0:27:38 > 0:27:41Subtitles by Red Bee Media Ltd
0:27:41 > 0:27:44E-mail subtitling@bbc.co.uk