Planet Dinosaur

We are living through THE golden age of dinosaur discoveries.

From all over the world, a whole new

generation of dinosaurs has been revealed.

From the biggest giants...

and the deadliest killers,

to the weird and wonderful.

From the Arctic,

to Africa.

From South America, to Asia.

Using the latest evidence, for the first time

we have a truly global view of these incredible animals.

In this episode,

we explore the dinosaur's extraordinary ability to survive.

And witness how they have transformed over millions of years

into some of the most alien-looking animals the world has ever seen.

This astonishing capacity to evolve

into ever more diverse and bizarre forms

meant that it helped them not only spread throughout the world,

but also dominate life upon it.

Dinosaurs lived for on Earth for more than 160 million years,

most famously throughout the Jurassic period.

But it was during the later Cretaceous period that the biggest,

baddest and most bizarre dinosaurs lived.

By the end of the Cretaceous,

dinosaurs were flourishing on every continent.

Even dinosaurs that had been around for over 100 million years,

like the giant, plant-eating sauropods, were still thriving.

Back then, Europe was a series of large islands.

On one of these, Hateg Island,

a giant dinosaur showed a most surprising adjustment to island life.

Cut off from everywhere else,

Hateg Island has its own unique collection of animals.

Bradycneme is one of the predators here.

Magyarosaurus, a plant-eater,

is the potential prey.

And it's the youngest which are in greatest danger from predators.

Hateg is a island where much is not as it first appears.

This is a world turned upside down.

They may look like giants

but the Magyarosaurus from Hateg Island

actually stood no taller than a pony.

Weighing around one tonne,

they are fraction of the size of their mainland relatives.

And weigh at least 70 times less than their cousin Argentinosaurus.

On the island of Hateg,

there simply wasn't enough food to support a plant-eating giant.

So, over many tens of thousands of years, they adapted,

creating a world were many of the dinosaurs were pocket-size versions

of their relatives.

But some animals are still huge.

This is the largest flying vertebrate ever known.

A pterosaur with a ten-metre wingspan.

It's as tall as a giraffe,

standing over five-and-a-half metres.

Discovered in 2002...

its skull alone is three metres long.

This is Hatzegopteryx.

A giant that we assumed hunted from the skies.

That was until the discovery of a series of fossil footprints,

unlike any found before.

The footprints were those of a giant pterosaur,

and they showed that these creatures did not just fly,

but could comfortably walk on all fours.

It seems these monsters actually hunt on the ground.

Hunting with impunity, Hatzegopteryx are the top predators.

SHORT SCREECH

THEY SCREECH

Able to fly from island to island, this is their kingdom.

Hateg island is one example of the strange paths evolution can take.

But all over the world, bizarre-shaped dinosaurs

continually evolved throughout their long reign.

Perhaps the strangest of all dinosaurs

is one particularly weird group, Therizinosaurs.

And the best example of these peculiar animals

was announced in 2009.

The skeleton revealed the secrets of this strange creature

that lived in New Mexico 92 million years ago.

These swamps are home to zuni-tyrannus,

a mid-sized tyrannosaur.

GROWLING

And they're also home to this weird creature, Nothronychus.

It's actually a close relative of the tyrannosaur,

but with one major difference.

Nothronychus has given up eating meat.

Here, the tyrannosaur is the top predator.

GROWLING AND SNARLING

Therizinosaurs had been a mystery for decades,

known only from tantalising fragments.

That all changed with the discovery of Nothronychus.

It gave us our clearest look at this strange group of dinosaurs.

It walked upright on short, stocky legs.

It had wide hips, and a long neck.

Its teeth showed that these weren't the teeth of a killer.

Far from its ferocious tyrannosaur cousins,

this pot-bellied dinosaur had evolved into a strict vegetarian.

But armed with viciously long claws on its forearms,

it was by no means defenceless.

GRUNTING AND GROWLING

By becoming a plant eater,

Nothronychus has easy access to food.

And because it walks on two legs,

it can use its claws to pull down branches to reach leaves.

Nothronychus thrives here

because it doesn't compete with the tyrannosaurs for food.

GROWLING

But just because you're not competing for food

doesn't mean you're not seen AS food.

These are dangerous places to be at the bottom of the food chain.

Unable to run, Nothronychus relies on brute strength.

GROWLING AND SNARLING

Tyrannosaurs are predators that will eat anything,

even one of their own, whether they've killed it or not.

And a discovery found in Montana of a number of meat-eating dinosaurs

appeared to show that being such an unfussy eater

could have dramatic consequences.

It seems scavenging can hold hidden dangers.

This tyrannosaur wasn't killed by Nothronychus.

There's a more deadly killer at work here.

All the predator's bones were found alongside

the edge of an ancient stagnant lake.

And all of them died at the same time.

Similar mass killings have been found today among birds.

And the killer - a fast-acting, naturally occurring deadly disease.

Botulism.

Botulism is caused by bacteria that can thrive in rotting carcasses.

We think that the dinosaurs too

might have been victims of this lethal and invisible killer.

Once a carcass is poisoned,