Original subtitles

Over 66 million years ago...

SCREECHING WAIL

..our world was ruled...

BELLOWS

..by dinosaurs.

The largest animals that have ever walked the Earth.

Today, dinosaur experts across the globe

are uncovering the bones they left behind...

..allowing us to imagine how these extraordinary creatures

may have lived...

..so that we can tell their stories.

SHRIEKS

And they...

..can walk again.

ROARS

Nine million square kilometres of parched sand.

The Sahara Desert is one of the most inhospitable environments

on Earth.

But for dinosaur hunters, like Dr Nizar Ibrahim,

it's a gateway to a lost world.

Deep in a remote part of the desert, known as the Kem Kem,

Nizar and his team are excavating the remains

of one of the largest predatory dinosaurs that ever lived.

Is it broken there?

I don't know. It seems to be one bone here and one here.

Wow.

A spinosaurus.

Oh, that is beautiful.

What do you reckon? Maybe a rib?

Or a rib, yeah.

I knew we'd find one.

Using the team's discoveries,

we can imagine how it lived and died...

..100 million years ago.

In the Late Cretaceous period...

..Africa has just broken away from South America.

And the land that will become the Sahara...

..is a river system.

Its waters support acres of scrub and forest

that provide shade from the intense Cretaceous sun.

Perfect for an afternoon nap.

GENTLE SNORTING

This is Sobek the spinosaurus.

11 metres long.

His powerful jaws packed with teeth.

Disturbing this monster's sleep...

..could have deadly consequences.

HIGH-PITCHED CLUCKING

HIGH-PITCHED CLUCK

LOW GROWL

HIGH-PITCHED WAIL

But this isn't lunch.

HIGH-PITCHED CLUCKING

It's one of his babies.

Sobek is a father.

Like some species of modern birds, once the eggs are laid,

the job of looking after the kids falls to him.

YELPS

YELPS

Sobek must keep his young family alive...

..until they can fend for themselves.

PNEUMATIC DRILLING

100 million years later...

Looks like bone.

You got the location mark all right?

...Nizar and the team are starting to uncover evidence

that could shed light on how spinosaurus raised their young.

See more? Any luck on that side?

Bones that show Sobek wasn't built like other dinosaurs.

So, Marco, you can see this nice little curvature here.

I think this is certainly a vertebra.

It's a little fragile, this one.

This vertebra was part of Sobek's six-metre tail.

All right, let's get it out, and let's see if we can find more.

In total, the team has recovered more than 40 tail bones.

This will be vertebra number...22?

- Yeah. - OK.

- Starting from the smallest one? - We're starting distally, yes.

And for Nizar and fellow palaeontologist Francesca Borchi,

they reveal something unique.

What I think is really remarkable is, like, you get close

to the tip of the tail, and you still have these really long spines.

Spines like these are not found

on the tail bones of other predatory dinosaurs.

Once you see the shape of the spines, it's quite narrow.

- Yes. - And...and flat.

Basically just a giant paddle.

Yeah.

- The more we collect, the more aquatic this thing becomes. - Yeah.

For Nizar, a thin flat tail can mean only one thing...

..Spinosaurus was a swimmer.

WATER SPLASHES

Underwater, Sobek is in his element...

...using his huge tail to power him through the water.

He's guarding a nursery pool,

the place he and his babies call home.

And with Dad's back turned, the kids take to the water.

This secluded backwater is the perfect learner pool.

CROAKS

So, while Sobek's patrolling,

the babies hone their hunting skills.

But it's not long before one of them gets into trouble.

If it doesn't get help soon...

..this baby will drown.

Dad to the rescue.

CROAKING CALL

With everyone safely back on the bank,

the family settles down to sleep.

But they must soon leave the safety of the nursery pool

and travel somewhere Sobek knows they can catch

far more substantial prey.

And the journey ahead will be fraught with dangers.

Because, although the dig site is barren and lifeless today...

..Nizar and the team have evidence that when Sobek was alive,

the Kem Kem was far more perilous.

Lots of big predatory fish.

There's a nice...nice jaw.

Absolute monster.

Its rivers teemed with massive carnivorous fish...

Ah, this is nice.

..and enormous crocodiles.

Look at that.

OK.

Tip of the snout, right?

This is where the nose end is, essentially.

This will be the size of the biggest crocs today.

Big, nasty elosuchus.

Elosuchus is an extinct species of croc,

with jaws over a metre long.

This tooth is very nice. Still here.

Yeah, they're pretty, er, robust.

If the rivers were dangerous...

Carcharodontosaurus tooth.

..the land was home to an even more deadly predator.

Yes, it's very well preserved.

I can see all of the serrations here.

Like a steak knife, right?

Carcharodontosaurus was the T-rex of Africa...

..three metres tall

and armed with more than 50 flesh-cutting teeth.

Got several T-rex-size predatory dinosaurs,

or even bigger than T-rex, big crocs, giant fish.

- Not very safe. - Yeah.

You know, there are really many different ways to die.

These lands were once home to more large predators

than anywhere else in Earth's history.

A fearsome collection of carnivores...

..that Sobek must navigate...

..if he's to feed his family.

And there's danger lurking at every turn.

CROAKING CALL

Hidden from view, the murky waters are patrolled

by at least eight species of ferocious crocodile.

CROAKING CALL

But that's the least of their worries...

RUSTLING

..because the family has just entered the territory...

LOW SNARL

..of carcharodontosaurus.

This fearsome six-tonne killing machine...

..is also on the hunt for food.

ROARS

SCREECHING

LOW GROWLING

ROARS

ROARING

Time to get the babies to safety.

ROARS

With so many deadly predators around,

it will take everything Sobek's got to reach his destination...

..without his family becoming someone else's meal.

And not far from the dig site, on a remote plateau...

..the team has discovered signs of another monster...

- You good? - OK.

Good. I'm ready to go whenever you are.

..evidence that's best seen from the air.

DRONE WHIRS

So, how many pictures are we taking in total?

About 500, 600.

So, if we start down that ridge,

and then work our way over and do that whole site.

The photographic survey reveals what's hidden here.

Arranged in rows, these aren't just boulders...

..they're footprints.

This is a dinosaur trackway.

And to identify which dinosaur made it...

- Really big one. - Wow.

..Nizar and colleague, Dr Roy Smith, take a closer look.

You've got this edge here,

and then quite a nice shape around that side, as well.

Yeah, very nice.

Each footprint is a cast of the foot that made it.

- So, the claw over there, right? - Yeah, yeah.

- And I think there's two more there. - Yeah.

- The back of the foot. - Yeah.

And at over a metre across,

they're some of the biggest ever found.

- No. - No.

- This is really impressive. - Yeah.

There's a bit missing, or it would have been even bigger.

It would have been even bigger.

- We've got a giant here. - Yeah, yeah.

These footprints were made

by one of the largest dinosaurs that's ever lived.

Titanosaurs - huge long-necked dinosaurs, 14 metres high.

At more than 60 tonnes,

each one weighs as much as a herd of elephants.

DEEP BELLOW

But for one elderly member of the group...

..this has become its final resting place.

And it could provide Sobek with the food he needs

for his hungry babies.

But they're not the only ones

on the lookout for a free lunch.

LOW GROWL

An adult carcharodontosaurus...

ROARS

CHITTERING

..has already laid claim to the carcass.

ROARS

With his babies to look after, Sobek can't risk injury...

..so he must now decide if it's a prize worth fighting for.

GROWLING

Sobek is bigger.

But one bite from these jaws could be fatal.

Sobek's fearsome claws could give him the advantage.

But, crucially, the carcharodontosaurus...

..is built for hunting on land.

ROARING

HISSES

So Sobek backs down.

BABIES CHITTER

His family won't eat today.

But if they can survive their journey,

a much bigger prize awaits.

As night falls,

Nizar and the team examine an astonishing fossil.

The place where this was found, it was so narrow

you could only just crawl on your belly, essentially.

Discovered close to the dig site,

it's the remains of an extinct species of fish.

This is the head of onchopristis.

The brain case,

the blade-shaped snout, it's all there.

Onchopristis is commonly known as a sawskate

because of the long snout, lined with barbs,

it used to stun its prey.

This would have been a fairly slow,

bottom-dwelling skate-like animal.

OK.

But that's insane.

And with spinosaurus so at home in water,

Nizar has a theory.

So, this would have been

one of the primary food sources for spinosaurus.

- Incredible. - God, it's amazing. Wow.

Sawskate could grow up to four metres in length...

..so a single fish would make a sizeable meal.

But once a year, like rays do today,

it's thought they gathered to breed...

..in their thousands...

..providing an incredible feast...

..that awaits Sobek and his family.

BABIES CHITTER

But in this predator-infested land,

danger can strike at any time.

SCREECHING

HAMMERING AND DRILLING

And 100 million years ago...

..there weren't just predators on land and in the water.

They were also in the air.

So, this is a lower jaw of alanqa.

This is a Kem Kem pterosaur.

It is a pretty remarkable specimen.

Uh-huh.

Alanqa was a huge flying reptile

with a seven-metre wing span...

..twice that of any bird alive today.

Essentially, what we're looking at here is

the skull would be going back, you know.

- Like this. - Yeah, something like this.

A metre, more or less.

- Yeah. - Pretty big.

Yeah, it's probably the largest Kem Kem pterosaur.

Its jaws reveal

what this flying monster would have eaten.

It's got this really interesting

raised structure here.

- It's got, like, a Y shape. - Mm-hm.

There's a corresponding matching part

in the upper jaw,

and so maybe this was something

that was used to crush hard-shelled prey.

Although it's adapted to eat shellfish,

alanqa was so big, it didn't need to be picky.

It's possible that these things

were catching little things on the ground,

you know, when they walk on the ground.

Maybe little dinosaurs, little crocs, amphibians,

whatever they could catch.

Yes, yes.

With alanqa about, no small creature was safe.

ALANQA SHRIEKS

SHRIEKS

To reach the sawskate breeding ground,

Sobek must lead his young family through the forest.

It's their final challenge...

..but the most deadly.

For alanqa, a young spinosaurus would make a tasty meal.

SQUEAKS

LOW GROWL

And the dense foliage provides perfect cover...

..for an ambush.

SQUEAKS

SNAP

TWIG SNAPS

SQUEAKS

SQUEAKS

SQUEALS

GRUNTS

Too late.

ROARS

Having come so far...

..losing one of his babies is a huge blow.

CROAKING CALL

But if Sobek is to keep the others alive,

he must keep moving.

As the family emerges from the forest...

..their journey's end is in sight.

The sawskate breeding ground...

..and the promise of plentiful food

for Sobek and his family.

But for his babies to eat,

Sobek will have to fight his way

to the front of the queue.

HAMMERING

INDISTINCT CHATTER

And at the dig,

Nizar and palaeontologist Dr Gabriele Bindellini

have evidence that could reveal

how spinosaurus settled their differences.

So, I think this is the tallest we've got.

Mm-hm.

And it still miss a good portion at the tip.

Yeah, I mean, I think we're missing 30, 35,

maybe even 40 centimetres.

Mm-hm. Which makes it super long.

Yes.

- Do you want to take this end? I'll hold it here. - Mm-hm.

Over 1.5 metres long,

this is one of the 15 bones that rose up from Sobek's back,

supporting his enormous sail.

- I've tried to visualise all of his other spines. - Mm-hm.

I mean, it's a massive structure.

Spinosaurus sails are so big...

..they must have had an important function.

It's probably, like, primarily

a display structure to, you know...

- To be seen from the distance. - Yeah, like...

- Peacock. - Yeah, like a peacock's train.

But unlike a peacock, Nizar believes

the main function of spinosaurus's sail

might not have been to find a mate.

So, you're one spinosaurus, and you come close

to another spinosaurus's territory...

- Yes. - And what are you going to see?

You're going to see this big sail, right?

And just by looking at the sail, you can go,

"Ooh, there's a really big spinosaurus.

"I'd better not get close to this guy."

"Stay away from here."

I think it would be very efficient

- at scaring off, erm, other predators or rivals. - Yeah.

Sobek's intimidating sail

could be just what he needs...

..to win a prime fishing spot.

Having run the gauntlet of Kem Kem predators,

there's now only one thing

standing between him and feeding his babies.

A rival spinosaurus.

LOW GROWL

ROARS

Sobek must try to intimidate this older male...

..and take his place on the bank.

ROARS

So he initiates a ritual dance...

BOTH GROWL

..showing off his sail.

But as a young male, Sobek's sail is smaller...

BOTH GROWL

ROARS

..and not intimidating enough.

ROARS

Forced from the bank where the fish are easier to catch,

the job of feeding his hungry babies...

..has just got much more difficult.

HAMMERING AND SCRAPING

Can we get some measurements, Marco?

But evidence from the dig...

140.

..suggests Sobek may have been

well-equipped for the challenge.

CAMERA CLICKS

It's something we haven't really seen before.

- Something new. - Yeah?

One of the missing foot bones.

Yeah.

Sobek's foot bones are similar to those of water birds,

meaning his feet could have been webbed...

Here we are.

We're going to wrap it in this, tape it,

and this one we're going to put in a plaster jacket.

..helping him to swim after his prey.

INDISTINCT CHATTER

It's a tibia.

Where's the box?

And if he caught it, Sobek had another adaptation...

The teeth are really amazing.

..that made him a formidable underwater predator.

If I didn't know spinosaurus was here,

I would say this is a crocodile tooth.

Looking at it, the shape is basically the same, you know?

Unlike the broad blade-like teeth

of other predatory dinosaurs...

..spinosaurus teeth are smooth and conical like a crocodile's,

because they both eat the same food.

This is basically

your main piece of anatomical weaponry

- if you're going after fish. - Oh, yeah.

We're talking really big fish.

Stabbing slippery prey.

With more than 60 of these teeth

in its long jaws...

It's conical, it's...

..spinosaurus was able to tackle the largest fish.

Imagine having to hold on to a big sawskate

fighting for its life.

Yeah, it definitely wasn't an easy catch.

Yeah, I mean, they put up a real fight.

You need these kind of killing tools, right,

to hold on to the prey.

Webbed feet and spiky teeth are critical adaptations...

..that Sobek will need to make a catch.

But even so...

..success...

..is far from guaranteed.

Although Sobek is faster...

..the sawskate is more agile.

Time for a change of tactics.

Attacking from below...

..like a shark.

Success.

But getting his catch to his family won't be easy.

LOW GROWL

ROARS

WAILS

BOTH ROAR

This time, Sobek is in no mood to give up his kill.

BABIES CHITTER

By leading them to this land of plenty,

Sobek has ensured his babies' survival.

But his moment of triumph...

..has come at a terrible cost.

So, these are small parts

of the femur,

of the thigh bone, of our spinosaurus.

- Yeah, wow. - That's really nice, right?

Slices cut through Sobek's bones

have a disturbing story to tell.

We looked at some of the sections.

We looked at the growth lines under the microscope,

trying to look at the age.

- Oh, yeah. - They came out pretty nice.

You know, it's not as easy

as reading growth lines on a tree,

but we can narrow it down to an age

of 17 to 19 years at death.

OK, so he wasn't that old.

Yeah, like a young adult-ish, you know.

Mm-hm.

Other large predatory dinosaurs

are thought to have had a lifespan of about 30 years.

But Sobek's bones reveal

he was barely an adult when he died.

So, maybe he could have lived a little bit longer.

Yeah, if we assume a similar kind of lifespan

for a spinosaurus, you know, late 20s, early 30s,

it's a life cut short.

The evidence hidden within his bones...

BABIES CHITTER

..suggests Sobek may not have lived

to see his family grow up.

In providing for his babies...

..he has paid the ultimate price.

BREATHES HEAVILY

GASPS

EXHALES

GROANS SOFTLY

BREATHES SOFTLY

And as the great river ebbs and flows,

it covers his body

with layer upon layer of sediment...

..preserving Sobek's story

beneath the desert's shifting sands...

..until he is eventually found...

..100 million years later.

Next time...

..a gang of armoured dinosaurs

battles to reach adulthood...

..hunted by one of the most fearsome predators...

..that's ever lived.