Planet Dinosaur

We are living through

THE golden age

of dinosaur discoveries.

a whole new generation of dinosaurs has been revealed.

From the biggest giants...

to the weird and wonderful.

From the Arctic

to Africa.

From South America to Asia.

for the first time

we have a truly global view of these incredible animals.

we journey back 150 million years

to the Jurassic Period.

A time when the first giant killers stalked the earth.

But these giants weren't confined to the land.

Recent discoveries

have revealed an astonishing new hunter in the oceans.

These new giant killers posed the greatest of threats.

predator and prey were locked in a perpetual battle for survival.

we must travel back 150 million years

to a time when much of Europe looked like the Bahamas.

A time when these warm tropical seas were home to giant predators.

have left their mark

etched in stone.

This cliff face in Switzerland

is carved with a series

of enormous gouges and grooves.

Many over nine metres long.

The entire rock face is actually

an upturned slab of Jurassic Ocean floor.

And the marks were left by a predator

as it hunted for food.

Sharks like this squatina

are similar to angel sharks which still exist today.

It's an ambush predator and lies in wait.

But in these seas there are bigger hunters.

This is Kimmerosaurus.

They belong to a group called plesiosaurs.

they're one of the Jurassic Ocean's most successful hunters.

And also one of the most common.

And it's this unusual hunting method

that left its trace on the ocean floor

We now know that the rock face in Switzerland

is etched with the marks of hunting plesiosaurs.

But these giants were not the king of the seas.

Many of the fossils show evidence of having been violently ripped apart.

there were

much bigger predators

lurking in these seas.

in an island in the high Arctic,

a fossil was dug out of the frozen earth.

Its skull alone was nearly twice that of T-rex.

This was an enormous killer.

the like of which had never been seen before.

this is the most powerful marine reptile ever discovered.

Twice as big as most Jurassic Ocean predators...

an animal

that must go down in history as one of the ocean's most deadly hunters.

And it's prey like Kimmerosaurus

that are in its sights.

Skull analysis of giant killers

suggests that they hunted their prey by smell...

allowing them to silently hone in on their target.

we've calculated that Predator X

could move up to five metres per second -

fractionally faster than a Kimmerosaurus.

The kimmerosaurs only defence

is to head for the refuge of shallow water.

Predator X's size works against him.

Unable to hunt efficiently in shallow water...

..means that the Kimmerosaurus can use this as a refuge.

A subtle advantage that makes the difference between life and death.

Predator X and Kimmerosaurus

are just one example

of a predator-prey relationship

locked in a fight for survival.

In the western states of North America

is one of the richest sources of dinosaur fossils.

It's known as the Morrison Formation.

these rocks

have given us a tantalising glimpse

of how two dinosaurs adapted together

to protect themselves against another deadly predator...

..Stegosaurus and Camptosaurus.

Fossils of these two species

are almost always found

in the same area.

footprints of the two

were recovered from the same site.

It seemed that they lived alongside one another.

But why would two unrelated plant-eaters

live together?

Stegosaurus -

a heavily armoured tank

with a deadly weapon at the end of its tail...

known as a thagomizer.

Camptosaurus - a much smaller plant-eater

with no obvious defences.

DINOSAUR GROANS

Skull analysis shows

that Camptosaurus has bigger eyes -

and relative to its body - a much bigger brain.

Camptosaurus appears to be a lookout.

While the armoured Stegosaurus provides the muscle.

STEGOSAURUS GROANS

It's likely Camptosaurus and Stegosaurus

stuck close together for mutual protection...

..in a world where danger is ever-present.

Allosaurus -

a one-and-a-half-tonne ambush hunter with a lethal bite.

The world had never known a predator like it.

it's now faced with the prospect of either starving...

or facing the most well-protected giant of the Jurassic.

a predator needs to try to attack the stegosaurs from the front.

The evidence for encounters such as these is incredible.

directly link

revealing the unmistakeable signs