Planet Dinosaur

THEY GROWL

We're living through THE golden age of dinosaur discoveries.

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.

In just the last few years,

we have uncovered the most extraordinary fossils,

exquisitely preserved and tantalisingly intact.

Combined with the latest imaging technology,

we have been able to probe deeper and reveal more than ever before.

It gives us our first truly global view of these incredible animals.

Planet Dinosaur "Lost World"

In this programme, we're exploring the lost world of Africa.

For almost 100 years, this was a forgotten land.

Now, new discoveries have revealed

some of the most spectacular dinosaurs ever found.

Two giant killers,

both bigger than T Rex,

both living in the same place.

IT ROARS

One of these killers, more than any,

has captured the imagination.

A bizarre killer that we've only just managed to reconstruct,

in the last few years.

The story begins in Egypt, in 1912,

when fragments of a giant dinosaur were discovered.

A predator with two-metre-long spines rising over its back.

It was unlike anything seen before.

It was only in 2005, when a complete upper jaw was found,

that we could accurately reconstruct this bizarre creature.

With a skull almost two metres long,

this dinosaur was a colossal 17 metres

from nose to tail -

four metres longer than T Rex.

The reign of the dinosaurs began

almost 250 million years ago.

But this killer didn't appear

until a time known as the Mid-Cretaceous.

95 million years ago, its home in north Africa

was a desert surrounding a vast system of rivers and swamps.

The swamps are refuges for many large dinosaurs,

like the duck-billed Ouranosaurus.

IT BARKS

IT BELLOWS

They're also the hunting grounds for a killer.

IT BELLOWS

IT ROARS

IT SNIFFS AND GRUNTS

IT SNIFFS

IT BELLOWS

At seven metres and three tonnes, Ouranosaurs are big...

..but easily within the scope of a large predator.

IT BELLOWS

IT GROWLS

WATER SPLASHES

IT BELLOWS

IT SNIFFS

Spinosaurus.

At 17 metres, the biggest killer ever to walk the Earth.

An 11-tonne colossus.

IT RASPS AND GROWLS

However, for the time being,

these Ouranosaurs are off this killer's menu.

Spinosaurus is part of a family of dinosaurs

that are relatively newly-discovered.

Recent finds have shown that this strange group

lived from South America, through Europe, to Asia.

But the last and biggest of all came from north Africa.

Spinosaurus itself.

In 2010, analysis of their bones and teeth revealed something surprising.

Chemical traces found in the fossils suggested the Spinosaurus lived

more like a crocodile than other land-based dinosaurs.

It showed that they spent a large part of their lives in water.

IT BARKS

Spinosaurus is a predator, but one that hunts in water.

It's ichthyophagous - a fish-eater.

This is Onchopristis.

An eight-metre-long giant swordfish,

similar to those alive today.

The saw-like rostrum is lined with lethal barbs,

and is in itself up to 2.5 metres in length.

It's thought they migrated into freshwater rivers to breed,

where the young may be safer,

but the adults are exposed to new threats.

With their breeding season at its height,

these rivers are filled with Onchopristis.

It's the perfect hunting opportunity for Spinosaurus.

Spinosaurus's conical teeth evolved to grip prey

rather than tear off flesh.

For that, it needs powerful arms and claws.

IT GROWLS

GROWLING

With prey plentiful, Spinosaurus can afford to be wasteful.

A fact which other dinosaurs take full advantage of.

Rugops, an eight-metre carnivore.

Anywhere else, it might dominate.

But here, it is dwarfed by Spinosaurus.

Spinosaurus is unique, with long, narrow jaws

and nostrils set high on its head.

Its teeth were straight and conical.

They gave us a clue as to how it killed.

More evidence came in 2008,

when Spinosaurus' skull was put through a CT scanner.

It revealed a curious pattern of holes and sinuses in the snout

that looked just like those of crocodiles.

It's thought these contained pressure sensors,

sensors that, like a crocodile, can detect prey,

making it perfectly adapted to hunting in water.

This discovery gives us our best evidence of exactly how it hunted.

Able to hold its snout in the water because of its high nostrils,

it can strike without even seeing its prey.

GROWLING

IT GRUNTS

The ever-attendant Rugops has a weak jaw and skull. It's no killer.

It is a natural-born scavenger,

living off the scraps of this highly-efficient predator.

We can assume so much about the diet of Spinosaurus

because its fossilised teeth are commonly found

with the remains of the giant sawfish.

More recent discoveries appear to provide even more direct evidence.

In 2005, a Spinosaur fossil was found with a sawfish vertebrae

stuck in a tooth socket.

Another, discovered in 2008,

had a fragment of a sawfish barb apparently embedded in its jaw.

They suggested a clear predator-prey relationship.

Spinosaurus is the region's biggest killer

because it can exploit an environment so successfully.

A dinosaur at home in water.

For a time, it lived with little threat from other dinosaurs

and the species evolved into a 17-metre giant.

But Spinosaurus wasn't the only giant predator which thrived here.

Carcharodontosaurus. Land-based killer.

A meat-eater. A carnosaur.

A cousin of Allosaurus, but four times bigger.

With serrated teeth 16 centimetres long,

Carcharodontosaurus was a giant killer.

Up to 13 metres long and weighing around seven tonnes.

Like Spinosaurus, it too was bigger than T Rex.

Big predators need big hunting ranges.

Carcharodontosaurus may have needed up to 500 square kilometres each,

making competition for the best hunting grounds intense.