Kings of the Waterworld Planet Dinosaur Files

If you thought you knew all there was to know about dinosaurs,

think again.

This is Planet Dinosaur Files,

the series that rewrites the pre-history books.

We're bringing to life

the most awesome beasts ever to walk the Earth,

with state of the art CGI technology that makes you feel

like you're right there.

And I'll be discovering

what made these massive, lethal and, frankly, bizarre beasts tick.

I'll be taking the plunge to devise demos in my watery workshop,

where I'll be using fin power, backed up with a bit of muscle.

And I'll even be turning myself into a human crocodile.

In the last 20 years, scientists have discovered more dinosaurs

than in all the centuries that have gone before.

Amazing new discoveries.

They reveal a jaw-dropping cast list of creatures.

Bigger...

weirder...

deadlier, than we'd ever imagined.

This time on Planet Dinosaur Files,

we're asking the question,

which creature was king of the prehistoric water world?

You might think you know about prehistoric creatures...

..like the huge, 12-tonne plant-eater,

Diplodocus...

..or the mighty Tyrannosaurus Rex,

a savage predator who dominated on land for almost five million years.

But who ruled our planet's rivers and seas?

Prepare to meet some new watery wonders from the age before man.

Kimmerosaurus -

as long as a killer whale,

agile as a dolphin.

He ate sharks for breakfast.

Sarchosuchus -

a super-crocodile,

a terrifying reptile.

King of the prehistoric rivers.

And Predator X -

heavier than 20 hippos.

His jaws were stronger

than any dinosaur that has ever lived.

Three amazing creatures from the prehistoric waterworld.

But first, let's get something straight.

These creatures were gigantic reptiles,

with the weaponry and power to match many top dinosaurs,

but none of them were actually dinosaurs.

That's because a dinosaur stands upright on legs.

So prehistoric creatures that swam using fins or a tail

are not dinosaurs.

They're best described as marine reptiles.

But they lived at the same time as the dinosaurs,

and I'm going to look at what made these creatures so special.

First, how well do they swim through the water?

What equipment do they have to speed them through their watery world?

Next, size.

Is being big a great advantage for these marine reptiles?

And hunting.

What cunning ways do these predators have of catching their prey?

Let's meet our first contender.

Their home was these warm, tropical oceans

that once covered the continent of Europe.

This is Kimmerosaurus.

It's a type of prehistoric sea creature called a Plesiosaur.

Kimmerosaurus was six metres long,

the length of a killer whale,

and lived 150 million years ago.

They may look alien to us now,

but they shared the ocean with some very familiar fishy hunters.

Sharks!

This one's called a Squatina

and it looks similar to Angel Sharks

which can be found in the sea today.

The Squatina blends itself in with the sea floor,

so it can ambush passing fish.

But Kimmerosaurus has other ideas.

The hunter Squatina

is about to become the hunted.

Kimmerosaurs had a special way of hunting,

scraping the sea bed with their snouts

in search of prey hiding in the sand.

But how do we know this? By examining the evidence, that's how.

Check out this cliff in Switzerland.

It holds an amazing secret.

In 1998, these mysterious grooves were discovered

carved into this cliff face.

It's actually one giant fossil.

Rewind 150 million years.

That same cliff face, which is today 700 metres above sea level,

was then the bottom of the ocean.

And not only that,

those grooves could have been left by a hunting Kimmerosaurus.

This was a skilful hunter,

relying on speed and agility to fill its belly.

Look at those fins.

Perfectly suited to moving quickly in the water.

And there are creatures in our oceans today

that swim in a very similar way to Kimmerosaurus.

These sea lions have four fins, like Kimmerosaurus,

and a very similar swimming technique.

And look at these penguins.

We all know those stubby wings don't get them airborne,

but once they go underwater, it's almost like they're flying.

Look how nippy they are.

Time to head off to the Planet Dinosaur Files workshop,

which this week has moved to my local swimming pool.

So how good was a Kimmerosaurus's swimming technique?

Well, I'm going to try and find out in this swimming pool.

Now I can swim backstroke and front crawl and things like that,

but I haven't got the equipment to swim like a Kimmerosaurus.

So we've built this.

Now, it may look a bit big and bulky,

but actually it's only about half the size of the real thing.

And the Kimmerosaurus, he didn't swim front crawl like that.

The Kimmerosaurus used wings.

What they used to do was, sort of, flap these wings in the water,

to propel themselves at great speed underwater.

Now, Jim and I, the muscles of the Kimmerosaurus,

can't spend much time underwater, because of our lungs,

but we can operate these wings.

-Ready, Jim?

-Yeah.

-Let's go!

'We're timing how long it takes our Kimmerosaurus swimming model

'to get down this 25-metre pool.

'Just how good are those underwater wings?'

That's pretty astonishing.

I mean, just these four flapping fins

have managed to get well over a quarter of a ton of boat and rider

down a swimming pool in less than 45 seconds.

And obviously a real Kimmerosaur would be a lot smoother,

because they swam under the water.

They didn't have a big bulky boat with them.

I think it is a very effective swimming technique.

That's Kimmerosaurus. A weird, but wonderful, ocean creature.

For swimming, it was nearly twice as fast as an Olympic swimmer,

and agile with it.

Size? This predator was as big as a killer whale, at six metres long.

And hunting?

Remember, it had that clever way of flushing out prey from the sea bed.

But my search for a prehistoric king of the water world

isn't just limited to creatures from the sea.

This is a river in North Africa more than 95 million years ago.

A herd of massive Paralititans

is coming for a drink at the water's edge.

These were some of the biggest dinosaurs that ever lived.

And there's something about this river

that's making these plant-eating giants uneasy...

..crocodiles!

They may be dwarfed by the Paralititans,

but they're still dangerous.

And now this young Paralititan has got stuck in some mud.

The crocodiles smell dinner.

But what that young herbivore doesn't know is that there's a much,

much bigger threat lurking in these waters.

Meet the king of the crocodiles, Sarchosuchus.

Its name means "flesh crocodile." And this one's hungry.

An enormous 12 metres long -

that's the length of a whole railway carriage -

heavier than a fully-grown elephant,

weighing an astonishing eight tonnes.

Twice the size of any crocodile in the world today.

This is a super-crocodile.

But how can we be sure that a crocodile this big actually existed?

By taking a look at the evidence, that's how.

In Niger, Africa, in 2001, an amazing discovery was made.

A massive crocodile fossil.

A staggering total of 250 different bones.

Amongst all these bones was a huge skull.

Dinosaur experts measured it at a whopping two metres in length.

That's taller than most dinosaur experts!

Back on the prehistoric river bank, Sarchosuchus' enormous size

and massive jaws are a terrifying sight to this young Paralititan.

I don't fancy the chances of this youngster surviving.

Now, the prehistoric Sarchosuchus, although much bigger,

is very similar to crocodiles today.

Dinosaurs have long gone, but crocodiles have survived

and thrived for millions of years.

These ones are in the Nile river in East Africa.

A herd of wildebeest approach the water's edge.

The crocodiles get ready to spring a surprise attack.

Their tactic is to suddenly grab their prey in a vice-like grip,

and drown them in the water, where they have a deadly advantage.

Rewind 95 million years, and we find that even other big predators

had to take care when they entered the patch

of our super-croc Sarchosuchus.

Here the mighty Spinosaurus is looking for a meal nearby.

This normal-sized crocodile isn't really a threat.

But then Sarchosuchus emerges from the water.

Even though Sarcho is barely half its size,

Spinosaurus knows those powerful jaws could drag it underwater.

Taking him on is just not worth it.

You've got to hand it to Sarchosuchus,

when a terrifying dinosaur

like Spinosaurus decides to give it a wide berth.

Sarchosuchus, like all crocodiles,

was perfectly adapted to living in water.

True, crocodiles do have to come to the surface to breathe.

But they've evolved, to be able to spend

staggering lengths of time underwater.

If they're not moving, they can spend several hours

beneath the surface, without needing to come up for air.

They also have a special way of swimming,

that's different to sea lions or Kimmerosaurus,

the plesiosaur we've already met.

A crocodile's body and tail moves in a sideways action,

making a kind of S-shape through the water.

'It's time to find out

'just how effective that method was in practice.'

OK, now let's see how quick it is swimming like a Sarchosuchus.

First, I need a very long tail.

Next, I want to make myself look as frightening and sleek as possible.

And, finally, to be a top predator,

you need to be able to see underwater.

That's it. A Sarchosuchus!

'Kimmerosaurus took 45 seconds.

'But Sarchosuchus swims in a very different style.

'Will it be any quicker over one length of this pool?'

That, that is astonishingly quick! That is twice

the speed of a Kimmerosaurus.

And the thing is, once you get one of these big crocodile tails on,

you can feel the power in the water.

You can use every muscle in your body to propel yourself along.

And that's why the Sarchosuchus must have been

one of the most feared predators in prehistoric waters.

That's Sarchosuchus. A giant grandparent of the modern crocodile.

For swimming, that powerful tail made Sarcho

really fast through the water.

Size-wise?

Well, this beast makes a truly massive splash.

Eight tonnes and 12 metres long.

And hunting?

This killer could just as easily get its dinner on land

as in the water.

But was Sarcho the most fearsome beast in the prehistoric water?

Well, as it happens, far from it.

Because recently, dinosaur detectives have discovered

an even more gruesome killer.

It's so fearsome that even its name is terrifying.

This is Predator X.

A truly enormous monster.

More than 15 metres long and a massive 45 tonnes -

nearly five times the weight of the largest-known killer whale.

It had jaws more powerful than any dinosaur.

But how can we be sure that a creature this massive

once swam in our oceans?

By taking a look at the evidence, that's how.

These are very special prehistoric bones found in 2008.

They come from the island of Svalbard in the Arctic Ocean.

Here, a huge fossil was discovered. This was Predator X.

Its skull was found to be nearly twice the size

of a Tyrannosaurus Rex's.

Predator X was a monster.

If you were to put one on a set of weighing scales today,

it would take five double-decker buses to tip the balance.

So what exactly did this giant sea predator eat to get so big?

And how did it catch its prey?

Well, this predator hunted other smaller predators.

In fact, there's evidence that Kimmerosaurus could have been

top of the menu for this ocean monster.

Predator X hunted mainly by smell.

By passing water through special nostrils

inside its massive snout, it picked up the scent of nearby prey.

Now, often in the water, smaller can seem faster.

And as Predator X is three times bigger than Kimmerosaurus,

you might think that Kimmerosaurus

would be able to outswim this huge hunter.

Let's find out if that really is the case.

'Back to the pool, where I'm doing a spot of underwater engineering.'

Time to bring a bit of Predator X to the local swimming pool.

Now, in swimming style he's pretty much the same as Kimmerosaurus,

four large fins flying through the water.

The significant difference, he's much, much bigger.

There's the little old Kimmerosaurus one. Here's the big Predator X one.

Now, whereas Kimmerosaurus was about the size of a killer whale,

this thing, in real life, would have been

about the size of this swimming pool.

'Now, remember, our Kimmerosaurus swam a length in 45 seconds.

'But Sarchosuchus did the same distance twice as fast,

'just 22 seconds.

'How will Predator X get on?

'Once we get those massive fins into a rhythm,

'Predator X eats up the water.'

Just over 30 seconds! This thing's quick.

It's not quite as quick as Sarchosuchus,

which was very swift off the mark,

but noticeably faster than Kimmerosaurus.

And the fact is, the way it felt here,

Jim and I just don't have the power for waterwings this big.

And the difference is, real-life Predator X was a veritable monster.

He was like a 45-tonne torpedo.

And it had all the strength it needed to drive its massive wings

through the water, giving it the ability

to devour just about anything it wanted.

So, Predator X was no slow-coach.

In fact, dinosaur experts have worked out

that Predator X's muscle power and huge fins

gave it a maximum speed of five metres per second.

Crucially, and our demo backs this up,

that's faster than Kimmerosaurus.

And that could mean the difference between life and death.

But don't write off Kimmerosaurus.

It wasn't completely defenceless against an attack from Predator X.

Sometimes, being a lot smaller than the creature that's hunting you

can be an unexpected advantage.

These Kimmerosaurs have swum into the much shallower water

of this lagoon. This is a clever tactic,

because Predator X is just too big to get in here.

Now, you can see this kind of thing happening with sea creatures today.

These killer whales are hunting seals.

But the seals know that if they stay in water near the beach,

the whales won't be able to get them.

That's one hungry whale that's staying hungry a while longer.

Rewind again 150 million years,

and the tide is rising in the Kimmerosaurs' lagoon.

They think they're safe here,

but now it's become deep enough for Predator X to swim in.

However, the water's still too shallow for its big power advantage

to count against these more agile Kimmerosaurs.

But Predator X knows it will get its chance.

Eventually, the Kimmerosaurs will have to leave the shallows

so they can feed in deeper water.

And in the deep ocean, the odds swing back in his favour.

He just needs to wait.

Big sea predators come into their own in the deep ocean.

This Great White shark is searching for seals on the surface.

It can stay out of sight down in the murky depths

and then spring an ambush.

This amazing slow-motion film shows how,

by attacking the seal from below,

the Great White can use its maximum speed and power

to surprise its prey.

Just like the seal,

this Kimmerosaurus is hunting for food in deep water.

But that also means it's vulnerable to attack.

Predator X spots its prey from below.

Now it can use all its power and speed.

Just like the Great White shark,

it's all about a surprise attack from the depths.

That first incredible blow stuns the Kimmerosaurus and slows it down.

Now Predator X can finish the job.

Those jaws are an astonishing four times as powerful as T-Rex.

Kimmerosaurus is history.

So that's Predator X, a huge ocean hunter.

But how does this mega-monster from the deep

compare with our other amazing marine reptiles?

There was Kimmerosaurus. Sharks were its favourite food.

For swimming, it was rapid underwater and agile, as well.

Size-wise, it weighed one tonne and was six metres long.

And hunting?

It had a clever way of flushing out prey from the sea floor.

Then the massive Sarchosuchus, a very powerful super-crocodile.

Swimming? It was faster than Kimmerosaurus and Predator X.

For size, it was impressive - eight tonnes and 12 metres long.

Hunting? Well, it could take prey on land and in water.

And finally, the incredible Predator X,

with jaws stronger than any dinosaur.

For swimming, its huge bulk didn't stop it being frighteningly fast.

Size? Well, it was stunning - 45 tonnes and 15 metres long.

And hunting?

It was like a massive Great White shark,

using the surprise attack.

Predator X was truly astonishing -

a mighty monster that ruled the seas for 100 million years.

So, my pre-historic king of the waterworld is Predator X.

And by a distance.

Next time on Planet Dinosaur Files,

we meet the prehistoric super-heavyweights.

And find out just how much damage all that weight can do.

Subtitles by Red Bee Media Ltd