0:00:05 > 0:00:09We are living through THE golden age of dinosaur discoveries.
0:00:10 > 0:00:15From all over the world, a whole new generation of dinosaurs has been revealed.
0:00:15 > 0:00:17From the biggest giants...
0:00:19 > 0:00:21..and the deadliest killers,
0:00:21 > 0:00:23to the weird and wonderful.
0:00:32 > 0:00:33From the Arctic,
0:00:33 > 0:00:35to Africa.
0:00:35 > 0:00:39From South America, to Asia.
0:00:39 > 0:00:43Using the latest evidence, for the first time
0:00:43 > 0:00:47we have a truly global view of these incredible animals.
0:01:04 > 0:01:06In this episode,
0:01:06 > 0:01:10we explore the dinosaur's extraordinary ability to survive.
0:01:11 > 0:01:16And witness how they have transformed over millions of years
0:01:16 > 0:01:20into some of the most alien-looking animals the world has ever seen.
0:01:22 > 0:01:25This astonishing capacity to evolve
0:01:25 > 0:01:28into ever more diverse and bizarre forms
0:01:28 > 0:01:32meant that it helped them not only spread throughout the world,
0:01:32 > 0:01:35but also dominate life upon it.
0:01:39 > 0:01:44Dinosaurs lived for on Earth for more than 160 million years,
0:01:44 > 0:01:48most famously throughout the Jurassic period.
0:01:48 > 0:01:52But it was during the later Cretaceous period that the biggest,
0:01:52 > 0:01:56baddest and most bizarre dinosaurs lived.
0:01:56 > 0:01:58By the end of the Cretaceous,
0:01:58 > 0:02:01dinosaurs were flourishing on every continent.
0:02:01 > 0:02:05Even dinosaurs that had been around for over 100 million years,
0:02:05 > 0:02:09like the giant, plant-eating sauropods, were still thriving.
0:02:11 > 0:02:15Back then, Europe was a series of large islands.
0:02:15 > 0:02:17On one of these, Hateg Island,
0:02:17 > 0:02:22a giant dinosaur showed a most surprising adjustment to island life.
0:02:38 > 0:02:41Cut off from everywhere else,
0:02:41 > 0:02:44Hateg Island has its own unique collection of animals.
0:02:49 > 0:02:54Bradycneme is one of the predators here.
0:02:57 > 0:02:59Magyarosaurus, a plant-eater,
0:02:59 > 0:03:02is the potential prey.
0:03:04 > 0:03:08And it's the youngest which are in greatest danger from predators.
0:03:32 > 0:03:36Hateg is a island where much is not as it first appears.
0:03:52 > 0:03:54This is a world turned upside down.
0:03:57 > 0:03:58They may look like giants
0:03:58 > 0:04:02but the Magyarosaurus from Hateg Island
0:04:02 > 0:04:04actually stood no taller than a pony.
0:04:07 > 0:04:09Weighing around one tonne,
0:04:09 > 0:04:12they are fraction of the size of their mainland relatives.
0:04:14 > 0:04:19And weigh at least 70 times less than their cousin Argentinosaurus.
0:04:20 > 0:04:21On the island of Hateg,
0:04:21 > 0:04:25there simply wasn't enough food to support a plant-eating giant.
0:04:25 > 0:04:29So, over many tens of thousands of years, they adapted,
0:04:29 > 0:04:34creating a world were many of the dinosaurs were pocket-size versions
0:04:34 > 0:04:36of their relatives.
0:04:38 > 0:04:40But some animals are still huge.
0:04:44 > 0:04:47This is the largest flying vertebrate ever known.
0:04:48 > 0:04:52A pterosaur with a ten-metre wingspan.
0:04:53 > 0:04:56It's as tall as a giraffe,
0:04:56 > 0:04:58standing over five-and-a-half metres.
0:05:00 > 0:05:02Discovered in 2002...
0:05:04 > 0:05:07..its skull alone is three metres long.
0:05:07 > 0:05:10This is Hatzegopteryx.
0:05:13 > 0:05:17A giant that we assumed hunted from the skies.
0:05:34 > 0:05:38That was until the discovery of a series of fossil footprints,
0:05:38 > 0:05:41unlike any found before.
0:05:44 > 0:05:47The footprints were those of a giant pterosaur,
0:05:47 > 0:05:50and they showed that these creatures did not just fly,
0:05:50 > 0:05:53but could comfortably walk on all fours.
0:06:01 > 0:06:06It seems these monsters actually hunt on the ground.
0:06:12 > 0:06:16Hunting with impunity, Hatzegopteryx are the top predators.
0:06:21 > 0:06:22SHORT SCREECH
0:06:51 > 0:06:54THEY SCREECH
0:07:21 > 0:07:25Able to fly from island to island, this is their kingdom.
0:07:30 > 0:07:35Hateg island is one example of the strange paths evolution can take.
0:07:36 > 0:07:39But all over the world, bizarre-shaped dinosaurs
0:07:39 > 0:07:43continually evolved throughout their long reign.
0:07:43 > 0:07:46Perhaps the strangest of all dinosaurs
0:07:46 > 0:07:50is one particularly weird group, Therizinosaurs.
0:07:52 > 0:07:54And the best example of these peculiar animals
0:07:54 > 0:07:57was announced in 2009.
0:07:58 > 0:08:03The skeleton revealed the secrets of this strange creature
0:08:03 > 0:08:06that lived in New Mexico 92 million years ago.
0:08:19 > 0:08:21These swamps are home to zuni-tyrannus,
0:08:21 > 0:08:24a mid-sized tyrannosaur.
0:08:26 > 0:08:29GROWLING
0:08:36 > 0:08:42And they're also home to this weird creature, Nothronychus.
0:08:42 > 0:08:48It's actually a close relative of the tyrannosaur,
0:08:48 > 0:08:51but with one major difference.
0:08:51 > 0:08:54Nothronychus has given up eating meat.
0:08:59 > 0:09:03Here, the tyrannosaur is the top predator.
0:09:16 > 0:09:21GROWLING AND SNARLING
0:09:29 > 0:09:32Therizinosaurs had been a mystery for decades,
0:09:32 > 0:09:36known only from tantalising fragments.
0:09:37 > 0:09:41That all changed with the discovery of Nothronychus.
0:09:41 > 0:09:46It gave us our clearest look at this strange group of dinosaurs.
0:09:46 > 0:09:49It walked upright on short, stocky legs.
0:09:49 > 0:09:52It had wide hips, and a long neck.
0:09:52 > 0:09:56Its teeth showed that these weren't the teeth of a killer.
0:09:56 > 0:10:00Far from its ferocious tyrannosaur cousins,
0:10:00 > 0:10:04this pot-bellied dinosaur had evolved into a strict vegetarian.
0:10:06 > 0:10:09But armed with viciously long claws on its forearms,
0:10:09 > 0:10:12it was by no means defenceless.
0:10:12 > 0:10:16GRUNTING AND GROWLING
0:10:32 > 0:10:33By becoming a plant eater,
0:10:33 > 0:10:37Nothronychus has easy access to food.
0:10:40 > 0:10:42And because it walks on two legs,
0:10:42 > 0:10:46it can use its claws to pull down branches to reach leaves.
0:10:49 > 0:10:51Nothronychus thrives here
0:10:51 > 0:10:54because it doesn't compete with the tyrannosaurs for food.
0:10:54 > 0:10:57GROWLING
0:11:01 > 0:11:04But just because you're not competing for food
0:11:04 > 0:11:08doesn't mean you're not seen AS food.
0:11:28 > 0:11:33These are dangerous places to be at the bottom of the food chain.
0:11:34 > 0:11:40Unable to run, Nothronychus relies on brute strength.
0:11:43 > 0:11:46GROWLING AND SNARLING
0:12:07 > 0:12:11Tyrannosaurs are predators that will eat anything,
0:12:11 > 0:12:14even one of their own, whether they've killed it or not.
0:12:17 > 0:12:22And a discovery found in Montana of a number of meat-eating dinosaurs
0:12:22 > 0:12:27appeared to show that being such an unfussy eater
0:12:27 > 0:12:30could have dramatic consequences.
0:12:30 > 0:12:33It seems scavenging can hold hidden dangers.
0:12:34 > 0:12:38This tyrannosaur wasn't killed by Nothronychus.
0:12:40 > 0:12:44There's a more deadly killer at work here.
0:13:12 > 0:13:15All the predator's bones were found alongside
0:13:15 > 0:13:18the edge of an ancient stagnant lake.
0:13:20 > 0:13:23And all of them died at the same time.
0:13:23 > 0:13:28Similar mass killings have been found today among birds.
0:13:28 > 0:13:33And the killer - a fast-acting, naturally occurring deadly disease.
0:13:33 > 0:13:35Botulism.
0:13:35 > 0:13:40Botulism is caused by bacteria that can thrive in rotting carcasses.
0:13:40 > 0:13:42We think that the dinosaurs too
0:13:42 > 0:13:47might have been victims of this lethal and invisible killer.
0:13:49 > 0:13:51Once a carcass is poisoned,
0:13:51 > 0:13:55it is quickly passed on to any animal that eats it.
0:13:57 > 0:13:59With lethal results.
0:14:00 > 0:14:03But plant-eaters, like Nothronychus,
0:14:03 > 0:14:06are usually safe from such deadly killers.
0:14:06 > 0:14:09By completely changing its diet,
0:14:09 > 0:14:13Nothronychus shows the extraordinary adaptability
0:14:13 > 0:14:17of the group known as the theropod dinosaurs.
0:14:19 > 0:14:21These two-legged dinosaurs
0:14:21 > 0:14:24were the most diverse of all the dinosaur groups.
0:14:26 > 0:14:29From predators like Mapusaurus and Majungasaurus
0:14:29 > 0:14:32to the bizarre Therizinosaurs...
0:14:34 > 0:14:37..the extraordinary tree-living Microraptor,
0:14:37 > 0:14:39to the weird Gigantoraptor.
0:14:42 > 0:14:46They evolved into an incredible range of shapes and sizes.
0:14:48 > 0:14:51The tyrannosaurs were the most successful
0:14:51 > 0:14:53of the theropod predators.
0:14:54 > 0:14:58And once tyrannosaurs dominated in an area,
0:14:58 > 0:15:02many other meat-eating dinosaurs simply disappeared.
0:15:04 > 0:15:07But those that had changed their diets flourished.
0:15:09 > 0:15:13Mongolia, 85 millions years ago.
0:15:13 > 0:15:16One group of dinosaurs thrives here
0:15:16 > 0:15:21despite the fact that they live in the shadow of a deadly tyrannosaur.
0:15:21 > 0:15:27These are Oviraptorids, omnivores that eat animals and plants,
0:15:27 > 0:15:31and so don't compete directly for food with the biggest of killers.
0:15:35 > 0:15:37And the benefits are clear,
0:15:37 > 0:15:40because some of these creatures become huge,
0:15:40 > 0:15:43like the eight-metre Gigantoraptor.
0:15:49 > 0:15:53But this group have another trick to help them survive,
0:15:53 > 0:15:56the way they nest.
0:15:57 > 0:15:59In Mongolia in 1994,
0:15:59 > 0:16:04a nest of very large dinosaur eggs was discovered.
0:16:04 > 0:16:07An array of more than 20 eggs
0:16:07 > 0:16:10arranged in pairs around the edge of a shallow pit.
0:16:11 > 0:16:15They were the biggest dinosaur eggs ever found.
0:16:16 > 0:16:19When an embryo was found preserved within an egg,
0:16:19 > 0:16:23it proved that the nest, eggs and embryo
0:16:23 > 0:16:26were almost certainly those of Gigantoraptor.
0:16:34 > 0:16:38But nesting makes an animal vulnerable.
0:16:41 > 0:16:43Alectrosaurus.
0:17:06 > 0:17:09But against a pair of Gigantoraptors,
0:17:09 > 0:17:13a five-metre tyrannosaur has little chance of success.
0:17:30 > 0:17:33As Mongolia has given up it secrets,
0:17:33 > 0:17:37we have learnt more and more about these extraordinary creatures.
0:17:39 > 0:17:44In 2005, one particular fossil was found to contain two eggs
0:17:44 > 0:17:48within its body cavity, ready to be laid.
0:17:49 > 0:17:52Even more amazing were a number of other finds
0:17:52 > 0:17:55that revealed the nesting behaviour of these dinosaurs.
0:17:55 > 0:17:59Three dinosaurs were discovered, all sitting on top of nests of eggs -
0:17:59 > 0:18:03the dinosaurs sitting in the centre of the nest with their long arms
0:18:03 > 0:18:07spread out to protect the pairs of eggs arranged around them.
0:18:09 > 0:18:12These dinosaurs were brooding.
0:18:17 > 0:18:21Looking after their eggs increases the chance of them hatching.
0:18:23 > 0:18:28And having large eggs means the hatchling is more developed,
0:18:28 > 0:18:32making it less vulnerable to predators.
0:18:35 > 0:18:41But it takes longer to hatch - up to 80 days for Gigantoraptor.
0:18:44 > 0:18:46A time when both egg and the brooding parent
0:18:46 > 0:18:48are permanently at risk.
0:19:17 > 0:19:21Smaller Oviraptors are no more than a nuisance.
0:19:25 > 0:19:28Larger predators are a different story.
0:19:37 > 0:19:42Unwilling to leave the nest, the adult protects its offspring,
0:19:42 > 0:19:45first, by hiding...
0:19:59 > 0:20:03..and if that fails, it goes on the offensive.
0:21:10 > 0:21:12Protecting the nest
0:21:12 > 0:21:16means Gigantoraptors' young are more likely to survive.
0:21:20 > 0:21:23It now seems clear that the instinct to nurture
0:21:23 > 0:21:27and care for a nest of eggs had its origins with the dinosaurs.
0:21:28 > 0:21:31It's a behaviour that was so successful,
0:21:31 > 0:21:34it's still widespread today with birds.
0:21:34 > 0:21:37But the fossils show something else.
0:21:37 > 0:21:41These animals all died sitting on their nests.
0:21:56 > 0:22:01It seems that the threats don't always come from predators.
0:22:01 > 0:22:05Sometimes the real danger comes from the most unlikely places.
0:22:29 > 0:22:32These dinosaurs were all buried alive.
0:22:40 > 0:22:44Planet Dinosaur was an incredibly diverse and varied place,
0:22:44 > 0:22:49with these creatures able to colonise every continent on Earth.
0:22:51 > 0:22:53Continually evolving and changing,
0:22:53 > 0:22:57their dominance of life on Earth was absolute.
0:22:59 > 0:23:02Yet, they were doomed.
0:23:08 > 0:23:12Their downfall was caused by an asteroid smashing into the Earth.
0:23:15 > 0:23:18Travelling 20 times faster than a speeding bullet,
0:23:18 > 0:23:2115 kilometres across,
0:23:21 > 0:23:23it slammed into The Gulf of Mexico.
0:23:28 > 0:23:32The impact released more energy than a billion atomic bombs.
0:23:33 > 0:23:36The initial impact triggered wild fires,
0:23:36 > 0:23:39massive earthquakes and tsunamis.
0:23:39 > 0:23:44But most devastating was the debris blasted high into the atmosphere.
0:23:47 > 0:23:52This shrouded the planet in a cloak of darkness that lasted for months,
0:23:52 > 0:23:55cutting off sunlight.
0:23:55 > 0:23:58The Earth was thrown into almost permanent night.
0:24:01 > 0:24:03Animals that survived the blast
0:24:03 > 0:24:06were now faced with their greatest ordeal,
0:24:06 > 0:24:10as a devastating chain of events was set in motion.
0:24:14 > 0:24:17Deprived of light, many plants died.
0:24:18 > 0:24:23Plant-eaters like this Magyarosaurus are the first to be affected.
0:24:23 > 0:24:27With no food, the biggest succumb first.
0:24:29 > 0:24:34Fresh growth of plants offers a glimmer of hope,
0:24:34 > 0:24:38allowing smaller plant-eaters to scratch out a living.
0:24:38 > 0:24:43But these aren't enough to sustain anything for long.
0:25:06 > 0:25:10Scavengers initially have an easier time of it.
0:25:12 > 0:25:15As the plant-eaters succumb to starvation,
0:25:15 > 0:25:16there is a glut of food.
0:25:36 > 0:25:39But this surplus is an illusion.
0:25:44 > 0:25:48Once gone, scavengers will starve, too.
0:25:54 > 0:25:58The impact resulted in the collapse of whole food chains,
0:25:58 > 0:26:02and the extinction didn't just affect dinosaurs.
0:26:04 > 0:26:07Virtually all life on Earth was affected.
0:26:07 > 0:26:11More than 60% of all species were wiped out.
0:26:13 > 0:26:16Yet the extinction wasn't a lottery.
0:26:16 > 0:26:20One factor more than any other determined the dinosaur's fate.
0:26:22 > 0:26:23Size.
0:26:23 > 0:26:28On land, no animal weighing more than 25 kilograms survived.
0:26:31 > 0:26:37There just isn't enough food to sustain large animals.
0:26:39 > 0:26:44Ironically, it's the very thing that make dinosaurs so iconic
0:26:44 > 0:26:47that condemns them to extinction.
0:26:56 > 0:26:59The finds and discoveries of recent years
0:26:59 > 0:27:02have painted a staggering picture.
0:27:02 > 0:27:04Dinosaurs were incredibly adaptable,
0:27:04 > 0:27:08with an astonishing capacity for survival.
0:27:13 > 0:27:17Enduring the break-up of continents, sea-level rises
0:27:17 > 0:27:20and countless changes in climate,
0:27:20 > 0:27:23they continued to diversify and thrive.
0:27:26 > 0:27:29On land, in water,
0:27:29 > 0:27:33among the trees and even in the skies.
0:27:39 > 0:27:43They conquered every continent,
0:27:43 > 0:27:48dominating life on Earth for more than 150 million years.
0:27:51 > 0:27:55The most successful animals the world has ever known.
0:27:59 > 0:28:03It was only with an unprecedented extraterrestrial impact
0:28:03 > 0:28:07that finally saw the end of Planet Dinosaur.
0:28:31 > 0:28:33Subtitles by Red Bee Media Ltd
0:28:33 > 0:28:35E-mail subtitling@bbc.co.uk