Original subtitles

Over 66 million years ago...

SCREECHING WAIL

..our world...

HIGH-PITCHED CLUCKS

..was ruled...

SHRIEKS

..by dinosaurs.

DEEP BELLOW

HISSES

GRUNTS

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...

..and they...

..can walk again.

ROARS

Utah - in the heart of the American West.

Home to some of the most spectacular scenery on Earth.

And the forces that shaped the landscape

also make it a paradise...

..for dinosaur hunters.

In a remote part of the desert,

palaeontologists Dr Jim Kirkland...

..and Dr Josh Lively...

..have made a remarkable discovery.

So we've exposed quite a bit of bone, Jim.

Yeah.

The bones of one of the most heavily armoured dinosaurs...

..that ever lived...

Oh, that's cool.

..a gastonia.

Yeah, you might have a leg there.

Using their discoveries,

we can imagine how this youngster lived and died...

..113 million years ago.

In the Early Cretaceous period...

..the land that will become Utah

was warmer and wetter.

BIRDSONG

And what is desert today

is covered by conifer forests...

..and rolling meadows of ferns.

DEEP ROAR

Plentiful food...

..for groups of plant-eating gastonia...

..including youngster...George.

LOW BELLOWING

Like all young gastonia,

he must stick close to his parents...

..because danger...

..is never far away.

CHITTERING

CHITTERING

Utahraptor.

SNARLS

A heavyweight cousin of velociraptor,

the size of a grizzly bear.

And they hunt vulnerable young gastonia.

The ferns providing ideal cover

for a surprise attack.

Just yards away,

George and his family are oblivious...

..to the approaching danger.

SNARLING

With the raptors within striking distance,

the gastonia get a lucky break.

CRUNCH

SHRIEKING AND ROARING

Like many modern herd animals,

the adults form a defensive ring around their young.

Weighing over a tonne each,

covered in thick armour...

..a group of adult gastonia is virtually invulnerable.

With one of their group injured,

the raptors cut their losses.

But George can't rely on the safety of the herd

for much longer.

He's reached adolescence, when, like all young male gastonia,

it's thought he'll be pushed out of the group.

SOLITARY BELLOW

George must now grow up

without his family to protect him.

We'll probably do Dakota,

and at least one other person too.

At the dig, the team is starting to uncover evidence...

Is there a bone there coming up from somewhere?

Try and get your fingers under that if you can reach over.

..that might explain how young gastonia like George

survived to adulthood...

You got one over there. There's a big guy here.

Oh, OK. Looks like a limb bone.

Might connect to some of this bone right here.

..and the clues are coming thick and fast.

Beautiful! That's bone.

Looks like the rib might go into this one.

Everywhere they dig,

bone after bone emerges from the ground.

Found a couple of ribs right here,

going over top of a vertebra,

and then several pieces of armour.

A ton of bones just in this small spot.

It's too many to be from just one individual.

Got these thin rib-like sections.

Right. I mean, so far, you know, right in here,

there's probably parts of two animals.

And, intriguingly, all the gastonia found across the site

appear to be of a similar age.

From looking at skeletal remains,

we're looking at half-grown individuals,

you know, sub-adults to full adults.

Kind of analogous to teenagers, right? Yeah.

All these teenagers found together

suggests something unexpected.

BELLOWS

Since leaving his family group,

George has been living on his own...

..keeping deep in the forest...

..where it's easier to hide from predators.

SNUFFLES AND GRUNTS

But it's not long before he comes face-to-face...

..with another young male.

GRUMBLING ROARS

And it looks...

..like he means business.

Gastonia's skulls and necks are specially adapted

to act like shock absorbers.

But this isn't a fight.

This is how gastonia make friends.

Of all the armoured dinosaurs...

..they're one of the only known social species.

George has just joined a group.

It's a huge step forward,

dramatically increasing his chances

of making it to adulthood.

This gang of teenage boys will stay together

until they're tough enough to fend for themselves...

..because until their armour is fully developed,

they're vulnerable.

Just working our way around these elements,

trying to get around this big femur here.

At the dig, amongst the gastonia bones....

Hey, Josh? Check this out. What is that?

..the team makes an unexpected discovery.

Oh, wow.

That's really neat.

It's definitely not gastonia.

Hey, Jim? Yeah.

Heather found something interesting

and, uh, I'm wondering if you could tell me

whether or not it is what I think it is.

A nice curve.

Yeah, that's a small

therapod metacarpal end bone.

Could be a juvenile Utahraptor.

Utahraptor bones found alongside the young gastonia...

All right, I was right! It's a therapod metacarpal.

Yeah, confirm.

..suggest that throughout the gastonia's adolescence...

CHUCKLES

..Utahraptor was an ever-present threat.

TAPPING

And Josh and Jim have evidence that shows

just how deadly they could be.

A cast of a Utahraptor toe claw.

You know, you put the claw itself - you know,

this is the bone underlying it.

Just to be conservative, we could say it comes out

to about there, you know, in length. Yeah.

30cm long,

these killing claws were Utahraptor's primary weapon.

This thing might be kicking through inch-thick hide,

so fast you can barely see it.

Wam-wam-wam-wam! This thing's just punching lots of holes,

which would do a lot of damage.

These claws are the perfect tool

for puncturing the weak armour of young gastonia.

Maybe you have to think of it more as a can-opener.

Yeah, if it can flip it over,

use that to slice open the belly.

Yeah. These things are one of the most formidable predators

that ever lived.

Holding their toe claws off the ground

to keep them razor-sharp...

HISSES

..Utahraptor...

..is a finely tuned killing machine.

GRUNTS

SCREECHES

And this adult male...

..and the group he leads

have just entered the forest...

LOW BELLOWING

..following the trail of George and the gastonia gang.

But hidden beneath the thick undergrowth...

SCREECHES

..finding them won't be easy.

So the young raptors streak ahead...

SQUAWKING

..to try and flush them out...

..while the adults follow behind,

ready to make the kill.

With Utahraptor's eyesight

as sharp as modern birds of prey...

..even the slightest movement...

..could be fatal.

HISSES

So when they hear the raptors coming...

SCREECH

..the gastonia freeze.

LOW GRUNTING

The juveniles have missed them.

PANTS

But George must hold his nerve

because the deadliest threat is still to come.

SNUFFLING GRUNT

THUDDING FOOTSTEPS

The group leader.

HISSES

GRUNTS

It's a close call.

GRUNTS QUIETLY

But every day George and the gang survive

is a day closer to the safety of adulthood.

And emerging from the ground...

..clues that reveal even young gastonia...

..would have been no pushover.

BLOWS

Well, you should be getting close, I think.

Hey, Josh.

Get in my section, tell me what you think.

So...

There's so much here.

Plenty of osteoderms.

And they're coming out pretty solid, then? Yeah.

Osteoderms are the bones that made up the gastonia's armour.

That's a real nice one. Oh, yeah.

So you can kind of see on this one that kind of ridge right there,

that keel, that would point up.

Makes for a spikey dinosaur. It really does, yeah.

In life, each osteoderm was covered by a thick scale...

Now, this is one of the nicest ones we've had so far.

This would have been on the back of the animal.

..which would have created an armoured plate.

Where you see the hollow base that these have,

they're for blood vessels,

bringing nutrients up into this bone,

to grow that big scale that was on top.

There's a lot of armour on these animals.

It's a discovery that reveals the gastonia's armour

was nearly fully formed.

But the team has evidence

Utahraptor was one step ahead.

Revealed by an astonishing fossil found near the site

and taken to the lab for analysis.

Ah, it's a gold mine.

Yeah. It really is.

Entombed in this nine-ton block of sandstone...

..the team has discovered the remains of an entire group

of Utahraptors.

And over here,

we've got the string of articulated vertebrae.

Yeah. I mean, that's just beautiful.

And hidden amongst the hundreds

of perfectly preserved teeth and claws and bones...

Yeah, that's the great thing about this block.

We'll have so much material.

..curator Don DeBlieux has found something that could be

Utahraptor's deadliest weapon.

We got this beautiful little top of a skull,

and then we flipped it over.

Right here is the impression of the brain.

For a dinosaur,

this young Utahraptor brain is very large.

Yeah, certainly remarkable, given the size.

Yeah, that would be a very intelligent animal.

They would have been the most intelligent animal of its time.

Oh, certainly. Utahraptor would have been capable of

some pretty complex behaviours.

Spring has turned to summer.

And as the dry season sets in...

GRUNTING

..George and the gastonia gang leave the forest to find water.

They're still unruly teenagers...

GRUNTING

..but now in near-adult bodies.

And at the edge of the water hole,

clay-rich soil provides the gang

with essential minerals...

..vital for strengthening their armour.

And now the gastonia are tougher,

they're no longer an easy kill.

So the raptors change tactics.

DEEP BELLOWING

The group leader attracts their attention.

HISSES

..and uses his brightly coloured wing feathers...

..to create...

..a diversion.

Like a fox in a henhouse...

..the kill triggers the leader's predatory instinct.

SCREECHES

Trapped at the water's edge...

..it looks like George's luck has run out.

GRUNTS

INDISTINCT CONVERSATION

But at the dig,

Josh and the team have made a discovery.

They've come to retrieve a fossil

that may shed light on events that happened here

130 million years ago.

So, Don, I was originally thinking

it was down this drainage,

but looking at it now, I actually think

it's further over that way. Yeah, I think you're right.

But collecting it from the steep cliff face...

Damn! This is going to be tough.

..won't be easy.

It might be further that way, that's the thing.

Oh, there it is. Yeah, that's totally it.

Yeah. So, Don, I think

if you want to bring the back board over here

and then we can go ahead and start strapping it down.

With your legs. Do it.

This is a fossilised foot cast.

Big man on campus. All right.

All right, you got it. March on. Got it.

It formed when a dinosaur footprint

filled with silt and dust,

but over millions of years was compressed into solid rock...

Like that, OK? Just like that.

Luckily, it's not super fragile.

..creating a cast of the foot that made it.

All right.

One, two, three. It definitely gets easier up here.

OK.

OK.

But which dinosaur does it belong to?

Wow.

That's really cool.

We've got three big, wide toes on this footprint,

so that eliminates a couple dinosaurs right off the bat.

Yeah.

If it was gastonia, it'd have four toes.

And it's unlikely to be a predator

because there are no claws.

Most likely a plant-eater.

Yeah, I think a good candidate could be some sort of bipedal

plant-eating dinosaur, kind of like planicoxa.

Right, we're at the right level for those guys.

Or close. Absolutely.

Planicoxa were beaked, stocky dinosaurs that lived in herds.

You can imagine them travelling together

and moving long distances.

For sure. Maybe gastonia was year-round

and these dinosaurs were more seasonal.

All right.

You guide us, Steph.

Finding planicoxa footprints here

is an important discovery...

..because it suggests they migrated through this landscape.

BELLOWING

SNARLS

BELLOWS

As the group leader closes in on George...

HIGH-PITCHED ROARING

..a herd of planicoxa pass close by.

HIGH-PITCHED ROARING

And without any armour,

they're a much easier kill...

GRUNTING

..handing George...

..a very lucky escape.

But as the dry season intensifies,

the planicoxa herds will move on.

So, as George and the gastonia gang return to the forest,

they know it won't be long

until the raptors are hunting them down once more.

But coming out of the ground...

Let's see how long this is.

..further evidence the gastonia buried here...

We're looking at about 31.5cm long.

..were more than capable of defending themselves.

The proximal width, where it attaches to the tail,

looks like about 17.5cm wide. Yeah.

So, yeah, this is one of these specialised spikes

along the tail. Like, sticking out?

Yeah, yeah. So it'll be sticking out

from the sides of the tail.

You can imagine this with a big scale over top of it,

a bit piece of keratin,

so this would have come to a very sharp point.

And these, we think, were used as a weapon.

These blade-like spikes

were positioned along the entire length

of the gastonias' tails.

And Jim and Don have uncovered something

that shows just how these weapons were used.

And then, as I was trying to work on that,

I hit something over here.

So this is a femur, the upper-leg bone.

That's a pretty sizeable femur.

And then as I dug around,

I see we have a complete tibia, lower-leg bone.

Yeah.

You can see how short, you know, the lower leg is,

while the upper leg, about half the length...

Right. ..which is, you know, the exact opposite

than what you see in a running animal.

Gastonia had a top speed of around 5mph...

..because their hind legs weren't built for running.

They were adapted for a very different purpose.

Certainly, these things are not just simple bones.

They have huge muscle attachment points,

so they've developed powerful legs for serious,

strong manoeuvrability. Stocky guys,

just standing their ground.

You just see these things just holding on the ground

and swinging their tail with those big blades,

just like the one over there they already pulled out.

Yeah, that big boy.

Yeah. Slashing across,

and probably reach head-high easily,

and literally slap a Utahraptor, you know, right in the face.

Gastonia's powerful hind legs and spiked tails...

..mean George and the gang are now formidable adversaries.

RUNNING STEPS

But with the dry season now at its height,

and the planicoxa gone...

..the raptors are starving.

Desperate for food, they must take any opportunity...

..to make a kill.

But now nearly fully grown,

the gastonia gang will stand and fight.

HISSES

BELLOWING

HISSES

And this time,

they've got the weapons to defend themselves.

The gastonia now have the upper hand.

But driven by hunger,

the raptors have no choice but to attack.

HISSES

BELLOWS

With the group leader fatally wounded...

..the remaining raptors back down.

BELLOWS

But George's moment of triumph will be short-lived.

The hot summer months bring a new danger.

Something revealed by

a completely different type of evidence...

..found alongside the gastonia bones.

Palaeobotanist Dr Carol Hotton

is an expert in ancient pollen.

Howdy, Carol. Hey, Jim, take a look.

There's some interesting grains right in the centre.

So, if you see those little round grains

that look like flat tyres,

that's pollen from an extinct conifer.

And, um, there's another grain.

That's a member of the cypress family.

Hmm.

That was well adapted to dry conditions.

All the pollen Carol has identified

belongs to trees that lived in a parched, arid environment.

130 million years ago,

the forest that covered the dig site was a tinder box.

You can see all through the field

black pieces. Yeah, little shards.

Yeah, little shards. Twiggy-looking things

that are pretty small for twigs.

Right. In all probability, they represent charcoal.

It's unlikely to be anything else,

and I see that in all my pollen samples.

There's only one thing

that could have produced so much charcoal.

THUNDER ROLLS

The long, dry summer months

have created a time bomb.

As wildfire rages through the parched forest...

..it threatens the gastonia

and the surviving raptors.

CHITTERS

SCREECHES

BELLOWING

But George is slow to react to the danger.

BELLOWS

SQUAWKS

With a top speed around 20mph,

the raptors soon reach a clearing in the forest.

SQUAWKS

But they're trapped between the flames

and a treacherous marshy swamp.

And George and the gastonia gang aren't far behind.

The flames driving the two mortal enemies together...

..for one final showdown.

GRUNTS

This one is...

But back at the lab...

Oh, that's just...

..the sandstone block filled with raptor bones...

Now, this one here...

..has one last secret to reveal.

..right size...

Nice little jaw right there.

Oh, yeah. I see the teeth on that.

The amazing thing is that all these delicate little teeth

are all still in place in their sockets.

Oh, it's really remarkable to have it so well preserved.

Such high levels of preservation...

Hard to tell. And certainly this,

you know, still has the teeth included.

..tell the team the bones have not been disturbed.

The block captures the very moment the raptors died.

And interesting that

all the best-preserved bones all seem to be in this sand.

Yeah. It suggests that sand is part of why they died,

why they're so well preserved.

Although the sand is solid today,

Jim believes that when the raptors died,

it was liquid.

You know, what killed them is what buried them.

Given the geology of the setting,

most likely we're looking at a mass mortality tied to quicksand.

SQUAWKS

BELLOWS

HISSING

SHRIEKS

SQUAWKING

Panicked, the raptors run into trouble.

BLEATS

With the raptors out of the way...

..George has the chance to escape.

LOW BELLOWING

But they're struggling.

The very things that protected them from the raptors...

..heavy armour and short, stocky legs...

GRUNTS AND PANTS

..mean George and the gang

are too slow to escape the fire.

PANTS

One by one...

..the smoke takes its toll.

Buried where they fell...

..the landscape is transformed around them.

Layer upon layer of rock builds up...

..as the aeons pass...

..and the continents silently drift across the face of the Earth...

..until George and the gang are finally found...

..130 million years later.

Next time...

..T-Rex's lethal, faster cousin.

A young hunter fighting for her place

in the most ferocious pack on Earth.