Original subtitles

STEPHEN FRY: 'Dinosaurs. Prehistoric monsters.

'Huge, terrifying.

'I've always loved them. Always been fascinated by them.

'What's mind-boggling is that these extraordinary creatures

'roamed where we walk today.

'But what if I could go back in time,

'millions of years into the past,

'to the magical, dangerous world they lived in.

'I wonder...

'what would I make of them face-to-face?'

Oh, you can just pull up here.

Thanks.

Imagine being able to explore

their world and move with them.

HE CHUCKLES

It's just a dream, I suppose, but...

Well, I must get on with my life. Ha.

DISTANT ROAR

Mind you... you never know...

DRAMATIC MUSIC

ROARING

'For 180 million years, dinosaurs dominated our planet.

'In this series, I'm going to be transported back

'to the different eras of these awe-inspiring creatures...'

'..to immerse myself in their amazing, magical world.'

HISSING Hey! Don't do that!

'With the help of experts

'and the latest scientific discoveries from our time,

'we'll put their power and strength to the test,

'unravel their remarkable story from humble origins

'of the dawn of the dinosaurs

'to see how they evolved

'in a dazzling and bizarre array of forms to become giants...'

'..and produce some of the scariest predators

'ever to have stalked the earth...'

'..until their ultimate demise, wiped from the face of the planet

'in a single catastrophe of unimaginable power.

'Come with me as I travel back in time

'to encounter the dinosaur.'

'Reverse back time

'and the Earth we know today looked very different indeed.

'The land squashed together into one giant mass called Pangea,

'which covered a third of the planet.

'And as the Earth changed, so did the conditions.

'New and distinct worlds formed

'and each was home to its own class of unique characters.'

'Last time, we were in the Jurassic period

'to discover how the very first dinosaurs grew into monsters.'

BELLOWS

'Tonight, we're exploring the next key chapter in the dinosaurs' story,

'when a multitude of strange and exciting new species

'evolved to take over a fast-changing planet.'

'We're in a time period known as the Cretaceous.'

'The climate is one of the hottest in Earth's history,

'as much as ten degrees Celsius warmer than today.

'So hot, there's not even ice at the north and south poles.'

'Among the ancient conifers and ferns,

'appearing for the very first time are flowering plants and trees,

'as well as a remarkable new cast of dinosaurs.'

EXHALES

This is one of the most dynamic ages in dinosaur history.

An era that sees an explosion of diversity.

'Among an array of new species

'comes a group of highly effective predators known as raptors.

'The most famous is probably Velociraptor,

'a break-out star of the Hollywood movie Jurassic Park,

'which featured a couple of terrifying creatures

'teaming up to outwit their prey.

'Now I wonder how accurate that really was?'

Ah, there you are. Hello.

HISSING Hey! Don't do that!

Velociraptors are in fact about the size of a turkey.

Not quite the terrifying killing machines

that Spielberg brought to life.

Jurassic Park did somewhat exaggerate the Velociraptor's size,

but that was partly because of a dramatic discovery

that was made while the film was in production.

An entirely new and much bigger raptor.

DRAMATIC MUSIC, ROARING

SQUEALS

This is the Utahraptor.

Named after the American state where it was discovered in 1991.

It's really remarkable, isn't it?

Look how it has all those feathers over its body,

and yet it doesn't even fly.

Look at those remarkable flashes of red on its wings.

They're even brighter on the other side.

And those razor-sharp teeth mark it out as a vicious meat-eater.

It also has very sharp claws,

and those two huge ones there on its feet.

What are they for, I wonder?

But the raptors weren't the only dinosaurs to come into their own

during the Cretaceous. Hell, no!

'The trigger lies with those shifting continents.

'As we head from the Jurassic to the Cretaceous,

'the supercontinent Pangea fragments.

'This break-up isolates pockets of land

'where evolution starts to run along different tracks,

'producing a variety of new dinosaurs.

'In North America, there's the spikily-armoured Gastonia.

'In Africa, what is today Niger, the Ouranosaurus,

'with a huge sail on its back,

'thought to store food like a camel's hump.'

'And in south-east Asia in modern Laos,

'the Ichthyovenator,

'with a tapered snout able to pluck fish from the seas.'

The raptors are a key part of the Cretaceous dinosaur boom,

and Utahraptor here is the biggest one we know of - so far.

But what kind of predators are they?

Well, to discover that, we need to examine the evidence

the raptors left behind.

And to do that, we need to travel to Utah.

'Dr Jim Kirkland has been hunting dinosaurs in the US

'for over 40 years.

'He's found and named 26 new species.

'Back in 1991, he was about to make a momentous discovery.

'He and his team were digging at a quarry in central Utah

'when they unearthed a body part

'that could only have come from a raptor.'

DR JIM KIRLAND:'One of our guys called me over and said,'

Jim, "Will you take a look at this?"

Oh, that's a nice one. Yeah, you did good.

'And it was just sticking out'

from under the rock.

'And I'm looking at it and saying, "Well, that's a claw."

'I want you to uncover this,

'and I realise this is a giant dromaeosaur raptor claw.'

'It was by far the largest raptor claw ever discovered.'

This is a cast of a Deinonychus claw.

That was the biggest one in the world until we found this.

'It's a pretty formidable claw.'

'More fossilised bones followed,

'until Jim could reconstruct a full skeleton.'

'It revealed a creature that stood as tall as a man

'and weighed as much as two grand pianos.

This animal is Arnold Schwarzenegger.

It's got massive bones.

In fact, it matches very close

to the size of the animals in the movie.

'Jim named his new dinosaur Utahraptor,

'announcing his find the same month

'the movie Jurassic Park was released.

'Its large size was a match for Spielberg's infamous Velociraptors.

'But found in Mongolia,

'the real Velociraptor was in fact a mere half-a-metre tall.

'The largest raptor previously known at around twice that height

'was Deinonychus.'

'Utahraptor was half a metre taller still.'

DR JIM KIRKLAND: 'And this thing could kick the side out of the barn.

'These animals could run circles around any of us.'

'Jim's discovery has made Utahraptor the undisputed king of the raptors.'

'When you look at Utahraptor,'

basically scale it up to a large grizzly bear.

The kind of things that live in Alaska

and would rip your head right off.

RASPS

'The perfect guide to these creatures

'and to this key era in dinosaur history

'is a man who has made plenty of dinosaur discoveries of his own -

'Dr Dean Lomax.'

Well, hello, Dean. Hello, Stephen.

You're the man to tell me about these extraordinary creatures.

Beautiful, apart from anything else. Yeah. Fantastic beast.

The thing that really surprises me especially is, I'll be honest,

I think of a raptor, I think of a Velociraptor,

and I think of Jurassic Park, like most people - the feathers.

Mm.I mean, how do we know, and what are they for?

We know for sure because many other raptors

and relatives of raptors have been found with feathers preserved,

'and so if we go along the family tree of raptors,

'we can work out that even the predecessors of the ancestors

'of Utahraptor and Velociraptor had feathers.'

So the days of thinking of...

you know, almost scaly, slimy skin,

those days are over, really?

They're extinct. LAUGHTER

How do you know that it's a meat-eater, that it's a raptor?

What's the first clue that gives you that idea?

The first place you've got to go is right to the mouth.

You can see inside the mouth there you've got the sharp teeth.

They are not teeth for eating plants.

They're definitely for slicing through flesh.

Right. Steak knives.

Steak knives. Exactly.

But then look at the arms, as well, and the feet,

you've got the curved claws there,

and then you've got the long, stiffened tail, as well.

And then, of course, you've got the long legs, so...

this is certainly a hunter. Right.

A very beautiful animal, that's the surprise to me.

I would say that's a genuinely lovely creation.

LAUGHTER

I'm talking about it as if it's in the enclosure at Ascot,

but it would pass rather well there. I think it would be let in.

Yeah. Beautifully dressed. Fabulous.

Oh!

That's quite a turn of speed there.

And is that their superpower?

Yes, certainly one of them, yeah.

So speed is really important for Utahraptor.

At least the juveniles, or shall we say, the teenagers,

they were probably clocked at about 40kph, 25mph.

Pretty fast. That's faster than Usain Bolt.

Yes. That's quick, then, for something of that size,

because even though it's smaller than a lot of the famous...

things like Diplodocus, it's still a big creature.

It is still a big creature. Yeah.

So compared to other dinosaurs of the period,

they were the fastest, or amongst the fastest?

Certainly up there amongst the fastest

of the two-legged meat-eating dinosaurs.

DINOSAUR VOCALISING

Ooh, now here's something.

Oh! What's that?

Now that is a type of dinosaur called an iguanodontid,

and specifically, I think, this is one called iguanacolossus.

This is part of a big family of dinosaurs

that's had its roots, the very first of these were called iguanodon,

found here in the UK.

My goodness. And are they meat-eaters or vegetarians?

No, these are strictly plant-eaters. Oh.

So it's possible that this would be a prey animal

for our friend the Utahraptor?

Very likely. They lived together at the same time.

STEPHEN GASPS

Well, I think this one might be in danger of becoming lunch.

'But if it comes to a fight, will these placid plant-eaters

'have the pace or the power to survive a raptor attack?'

SCREECHING

'We're in the early Cretaceous period,

'when the dinosaurs flourished into a dazzling and bizarre array

'of very different forms,

'including a group of deadly predators

'that were covered in exquisite feathers, but couldn't fly...

'the raptors.'

'We're on the trail of this one,

'but it seems more interested in an iguanodontid

'that's grazing over there, quite oblivious of the threat to it.'

The thing I've been rather fascinated by

is as it's preparing, it seems,

to ambush this iguanodontid,

I can't help noticing those signature -

I don't know what you'd call them - toe claws that poke up.

What on Earth are they for? They're so unusual.

Yes, the old famous sickle-shaped toe claw.

This is something that was on the toe itself, it's the second toe,

and this, palaeontologists have thought,

maybe is it used for slashing?

Is it used for stabbing? Or maybe even climbing up trees?

Oh, good heavens. Yes, like someone climbing up a telegraph pole.

Exactly. But we know for sure

that it would have been used in close combat.

How'd you know that for sure?

Well, we have, would you believe, an exquisite fossil

that was found in 1971

as part of an expedition in Mongolia,

of a Velociraptor found with one of these claws

buried deep in the throat region of a Triceratops relative

called Protoceratops.

You have this behaviour that is locked in time, preserved forever.

Wow.

So I get the slasher/stabber role,

but what's so surprising is that it points upwards.

I can picture coming downwards, grabbing, but this?

You can see on the Utahraptor,

the claws are held up constantly in life,

up in the air, so the claw didn't actually touch the floor,

and the reason for that was to protect the claw itself

and keep it sharp and always ready for attack.

And if we're to believe Stephen Spielberg,

it taps its toes on the chromium floor of the kitchen,

or whatever it was that it was doing.

Yeah, I think that was done for cinematic effect.

I can't imagine that ever would have happened.

'To unravel the secret

'of exactly how Utahraptor used those vicious claws...'

'..engineer and dinosaur enthusiast Adam Wojcik

'is turning to the power of modern machinery.

'His team has constructed a set of robo dinosaurs

'to put the claws to the test.

'And he's getting the expert advice of palaeontologist Joe Bonsor.'

What we've done is we've got a motor here and a gearbox and a swingarm

and a nice, sharp steel claw.

What we want to look into is the idea that Utahraptor

and the other raptor-like dinosaurs

had this big slashing motion

that they could make with their claw,

and we want to see how effective that would really be.

'Adam's brought the Utahraptor's vicious claw

'back to life with two tests.

'The first uses a mechanical slashing limb,

'testing the popular idea that raptors disembowelled their prey.'

'The second test uses the claw to pierce and penetrate,

'more like an eagle's talon.

'Which will be more effective?'

'The slasher claw is up first.

'So, will it be able to slash through dinosaur skin?

'Some leather might give us an idea of what it would be like

'against a true prey animal, like an iguanodontian dinosaur.'

'The teams modelled the metal claw

'on the original Utahraptor fossil.'

This would be the bony core of the claw, and then it would

have been surrounded in like a keratin sheath around the core.

'It's time to put the slasher theory to the test.'

Oh. Wow. We've definitely got...

That's really interesting. ..no penetration there.

There's a bit of a scratch, but nothing major, really.

'The claw just bounces off the leather.'

So even though we've emulated the action,

it hasn't given you the end result.

And I guess this is showing us that this inside edge

wasn't used for cutting and slicing. Yep.

'Time for the second test, the piercing claw action.'

So this is the penetration rig.

'A hydraulic ram will simulate

'the pushing force of the Utahraptor's toe muscles.

'Will it be enough for the tip to pierce the tough leather hide?'

Are you ready? I'm ready. Let's do it.

'Three, two, one.'

Oh, look at that. Straight through.

So this does kind of give us some more weight

behind the theory that these were

using these claws more of a piercing tool,

to kind of cling onto the back of prey,

and then it would strike down with the mouth

and rip it apart, really.

But none of this slashing.

Yeah, and I think the idea that they were using these

to sort of slash about, a bit like Zorro,

is probably a bit just for the movies, I think, yeah.

OK, fair enough.

VOCALISES

I'm not sure where the Utahraptor has got to,

but I don't think it's going to end well for our friend here

if it gets within striking distance.

Interesting dinosaur, the iguanodontid.

Not nearly as famous as the great raptor, but they were actually

one of the first dinosaur species ever discovered.

So what else do we know about this docile dino?

'London's Natural History Museum

'is home to some of the most important

'iguanodontid fossils ever found,

'giving palaeontologist Joe Bonsor

'plenty of opportunity to unravel their secrets.'

'A complete skeleton is on display in the main hall,

'and behind-the-scenes,

'a set of giant teeth found back in 1822,

'long before dinosaurs were even known about.'

So these would have been

some of the first-ever Iguanodon teeth found in the world.

These were found along the side of a quarry,

in cuttings from the quarry.

'The discovery was made by husband and wife Mary and Gideon Mantell,

'amateur fossil hunters who spotted the teeth

'poking from rocks in West Sussex.'

'They look a little bit like iguana teeth,

'and that was the first thing that Gideon thought they belonged to,'

just something a lot, lot bigger.

'This is what led Mantell to coin the name Iguanodon,

'meaning "iguana's tooth."'

'Over time, more fossils emerged of this mysterious creature...'

'..including a single spike that Mantell assumed was a horn.'

'Based on the bones,

'Victorian artists tried to reconstruct this ancient beast.'

'It basically looks like a giant, big reptile,'

a big iguana, on all fours.

You can see the spike which was placed at the end of the snout,

kind of like a horn.

'But since then, scientists have discovered that the spike

'wasn't a horn after all.'

'Using 3D scanning technology,

'it's now possible to find the solution

'to this ancient jigsaw parcel.

'Along with scans of other iguanodontid bones,

'Joe is able to reconstruct a remarkable prehistoric hand.'

'The spike was, in fact, a vicious stabbing thumb.'

When they're all laid out like this,

you get a real sense of how this hand was put together.

So we've got the large thumb spike there,

and then we've got these three digits in the middle,

which it would have used as kind of a modified hoof for walking on.

The fifth digit was prehensile,

and it could curl it in towards the palm of the hand,

and could be used for grasping vegetation and leaves

and things like that.

'Seen also on the full skeleton,

'the thumb spikes gave the iguanodontid a secret weapon.'

In life they would have been coated in a horny kind of keratin sheath

that would have been really sharp,

'a lot like a claw to swipe at predators for defence.

'It could probably rear up on its hind legs

'and brandish these thumb spikes,

'and that would be enough to hopefully scare away the predator.

'It would have been a very formidable sight.

'I wouldn't want to mess with this at all.'

'So the iguanodontid may look rather placid,'

but it does have those spiked thumbs.

SUSPENSEFUL MUSIC

Let's take a look at how these vicious claws work.

VOCALISING

SCREECHING

Ah.

'Our iguanodontid's shaken off the first attack,

'but is Utahraptor about to go in for the kill?'

SCREECHING

'I'm in the early Cretaceous period, a key moment in dinosaur history,

'when they diversified into a huge range of new forms,

'including the deadly raptors.

'But can this one overpower a much larger iguanodontid,

'with its intriguing spiked hands?'

ROARING

RAPTOR YELPS

It turns out those spiked thumbs

really are a formidable self-defence mechanism -

even against the claws and jaws of the Utahraptor.

So, the iguanodontid gets away this time,

but clearly, the Utahraptor must catch its prey occasionally -

otherwise, it couldn't survive.

So, what gives it an edge

against plant-eaters like the iguanodontids?

'A bit of a search among the bushes,

'and I've found our Utahraptor, hunkered down,

'trying to recover from that vicious fight.'

It's clear that he hasn't lost his appetite, though.

And that alert glint in his eye

is a sign of a remarkable inner intelligence.

I think it's time we took a look inside the dinosaur brain.

'The key to the Utahraptor's success is hidden within its skull.

'Compared to other dinosaurs,

'its brain may look small and unremarkable.

'But once you factor in body weight,

'the Utahraptor's brain, proportionally,

'is two and a half times bigger than that of a T Rex -

'and 19 times bigger than a Diplodocus'.

'And this is evidence of far greater intelligence.

'Evolution in the Cretaceous period

'had produced one of the sharpest and smartest predators around.'

To help explain how they used that brainpower,

I'm joined again by dino expert Dean Lomax.

There's different kinds of intelligence.

There's intelligence you use for hunting,

for guessing what your prey is going to do,

and there's cooperation. There's cooperation,

hunting behaviours and stalking behaviours.

And in many respects, for something like Utahraptor,

in many cases, as a predator,

it just needs to be able to outfox its prey.

And working out that if they work cooperatively,

they can take down bigger prey,

which equals more food for the entire party.

And that takes a mixture, I suppose,

of the instinct that has evolved

and actual communication of some kind.

I mean, not language, obviously,

but some form of signalling or recognising, you know,

"You go round there and I'll wait here," sort of thing.

For sure, yeah. Especially when it comes to

trying to ambush its prey, potentially.

So, we know Utahraptors are intelligent, but...

did they really work together?

Well, the answer to that

seems to be coming from a clue found in rocks in Utah.

'In 2001, Jim Kirkland,

'the dinosaur hunter who first found and named Utahraptor,

'made a second remarkable discovery.'

When we first started to excavate the site, we knew, you know...

One of the first things I uncovered was a jaw with teeth in it,

and even on the same block, with the jaw,

there was also a big claw.

I was like, "Oh, that's nice." As we started excavating,

we realised there was a lot of bone material here.

Just a mass, a pod of sandstone and mud filled with bones.

'The team decided to remove

'the entire jumble of bones in one go,

'first encasing it in plaster,

'then transporting the nine-ton sandstone block

'out of the quarry and into Jim's lab.

'As they began to chip away the rock,

'they soon realised they had found a dinosaur death trap.'

Basically, this is a blob of quicksand

which has preserved dozens of Utahraptor skeletons -

adults, babies, two-year-olds.

Here's the shoulder blade of a pretty good-sized Utahraptor.

Of course, here's that sickle claw.

You know, that's from a juvenile.

Backbone. It's mostly buried there, but you can see the ribs going off.

Along here, there's, like, three animals right there,

laid in next to each other. So...

We see over a dozen animals on the surface,

and we know there are skeletons going down through a metre of this.

This is the first example

of a mass accumulation of Utahraptors.

And we believe they all died pretty much at the same time.

'But why would so many Utahraptors

'all fall into the quicksand at the same time?

'The answer lies in a second type of dinosaur

'Jim found entombed here.

'Plant-eating iguanodontids.'

What we see at this site is

there was an iguanodont adult and a juvenile,

apparently got stuck into this quicksand.

This here is probably the vertebra of one of the iguanodonts.

Another... The iguanodont stuff is kinda more scattered.

'For Jim, the presence of these prey animals

'alongside a group of meat-eating Utahraptors

'points to one remarkable explanation.'

I think they're pack hunting.

You would have had a ton, two tons of rotting meat.

That could have rung the dinner bell for these animals,

probably miles away.

You know, brought this pack in.

But it's certainly the attractor to this flypaper

where all these animals got trapped and killed.

'The quicksand has preserved an incredible snapshot

'from the age of the dinosaurs.

'What appears to be a family of Utahraptors,

'hunting together in a group.

'But for Jim, the work has only just begun.'

We may go down a few feet into this block,

cos there's bone bed after bone.

And maybe there's more than one mass mortality in here.

This'll be unravelled, probably, over the next couple of decades.

Ooh!

Looks like we might be in for a pack hunt.

There's an iguanodontid there that's being harried by some...

Yeah, those are Utahraptors, aren't they?

They sure are.

RAPTORS SCREECHING

ROARING

Now, that's fascinating,

because I've not really witnessed this...

pack behaviour before.

I suppose one of the reasons they can afford to cooperate

is there's enough reward of protein from their kill

to feed the whole family. That's exactly it.

I'm sure they're wanting to make sure the little babies,

the little chicks, get their fair share of food too.

Oh!

Looks as if the youngsters are finally gonna get their meal.

That sort of makes me wonder whether

there were, like, hierarchies of importance,

that the young ones had to eat afterwards,

and there were what we would now call alpha males or alpha females?

Yeah, I'm sure that something like that, a hierarchy,

at least in family groups like this, would have existed.

If they're working together cooperatively -

you think about, say, lions today.

Yes, you can sometimes see them batting away the young ones

as they try and get in, don't you? Yes, that's really interesting.

I'm getting a real impression

of a sophistication about this species, as we would see it.

That's to say you've got cooperation, communication,

bonding with your children and a hierarchy.

Yeah, well, most definitely.

'But there's a mystery I still want solved.

'It's only in recent decades

'we've discovered that some dinosaurs had feathers.

'But our raptors here clearly couldn't fly,

'which raises the question, "What are those feathers for?"

'One answer comes from the discovery

'that dinosaur feathers came in a remarkable range of colours.

'Palaeontologist Dr Jakob Vinther, at the University of Bristol,

'is using a scanning electron microscope

'to look for clues hidden beneath the surface of fossils.

'His ground-breaking research has changed the way we view dinosaurs.'

So, people have been looking at exceptionally preserved fossils

for many, many decades,

and had taken bird fossils, for example, preserving feathers,

and had looked at those,

and had identified these tiny little objects

that typically are shaped like little sausages.

'They looked like bacteria, come to feast on a dead corpse.

'But Jakob had another theory.

'Whilst studying fossilised squid and octopuses,

'he'd examined their preserved ink sacs.

'Under an electron microscope,

'the ink revealed minute ball-like features.

'Tiny containers for the ink's pigment,

'known as melanosomes.

'These structures bring colour to hair and skin

'among many animals today, including us humans.'

It made me think that if the melanosomes

can preserve so well here

and we can identify it using an electron microscope,

I thought to myself, maybe we can actually find preserved melanosomes

in, for example, a feathered dinosaur.

'The first flightless dinosaur ever to be found to have feathers

'was this one.

'Called Sinosauropteryx,

'its fossilised remains were unearthed in China,

'so Jakob decided to analyse its feathers.

'Sure enough, his hunch paid off.

'Under the microscope,

'he spotted the tell-tale shapes of melanosomes.'

And when they are small and round like this,

we see that that's typical of feathers

that was rusty red in colour.

So this particular sample here was ginger.

'Jakob's work has revealed a whole new world of Technicolor dinosaurs.

'And has shed new light

'on the presence of colourful feathers

'among the raptors.

'This raptor was unearthed in China.

'Its feathers, along with its arms and legs,

'helped it to glide between trees.

'And it was Jakob, through studying its fossil,

'who first discovered its true colours:

'a shimmering iridescence.'

We found very long and skinny melanosomes,

which tell us that this dinosaur was in fact iridescent,

so it had metallic sheens, like we see, for example,

in a peacock, or in a hummingbird.

The iridescence is quite unusual,

because if you think about modern birds,

if you have metallic sheens, it's typically for display.

So it's very remarkable to see that.

And therefore it suggests to us that maybe dinosaurs

in fact also used their feathers

to advertise themselves to each other.

'Our Utahraptor certainly seems to be using his colourful feathers

'to send a powerful message.'

SCREECHING

Whoa, Dean, what is that?

Are we under attack? Is that a threat?

'Having seen what he did to the poor iguanodontid,

'I don't fancy our chances.'

'Expert Dr Dean Lomax and I have come face-to-face

'with a meat-eating raptor from the Cretaceous period,

'when the dinosaurs produced an explosion of new species.

'And this one seems alarmingly on edge.'

That actually is a courtship display.

So, you see how it's using its feathers there.

You see the bright colours of the feathers as well.

So it's actually trying

to attract the attention of another Utahraptor, I think.

So we might not be a meal, but we might be a date?

I'm not sure that's any better, really!

Quite possibly!

Oh. What... What's he doing there?

Yeah, you can see it scratching the sediment there.

There's actually direct evidence

that we have from the site in Colorado,

in the States, of a dinosaur dance floor.

These dinosaurs... Seriously?

Seriously. ..scratching the floor.

And this is something that modern birds do as well.

It's a behaviour that's called lekking.Yes.

And they lek around,

they strut their stuff in front of onlooking females,

and they try to entice them, attract their attention.

And sometimes they tidy their area. They pick up sticks...

That's the sort of thing, exactly. And then the female, eventually,

after all the silky dance moves and the vocalisations by the birds,

and the same for the dinosaurs,

they then come, the female selects the partner,

they go away and do their, er, business.

Right! And for all we know,

they were giving out a boom, or a...

"Hello!" ..some sort of noise.

Of some description. And it would have been, yeah,

highly vocalised,

to just try and seem like the strongest individual.

The scratching, especially, is to show,

"Pick me, I can build a nest.

"And I'm the strongest of the individuals."

And presumably the wide display with the fringes,

like a cowboy's jacket, is also a kind of size, strength.

Definitely, yeah, showing the strength,

the size of this individual, compared to the other ones.

Is it us? Is it trying to attract our attention?

Oh, there we go. There's a female. Ah!

Oh, my goodness.

So, is she...

Is she on for it, do we think?

She looks like she might be interested.Yeah.

THEY CHUCKLE

Is she gonna swipe left or right? That's the big question, isn't it?

Wow.

'It looks like she's not quite ready to commit,

'but while we wait to find out,

'let's get ahead of ourselves and ask:

'What kind of parents might they make?

'Were raptors hands-on or nowhere to be seen?

'A good place to start is with crocodiles and alligators.

'These are some of the closest living relatives of dinosaurs.

'Baby crocodiles emerge from their eggs

'already able to feed themselves,

'just as dinos did.

'So for zoologist Rebecca Lakin,

'crocodile parenting offers one rather extreme model.'

Crocodiles, of course, are pretty poor parents, really.

The mum is really there just to stop her from being eaten by predators.

'A different extreme

'comes from the dinosaurs' other living relatives - birds.'

Birds take a much more active approach to parenting their young.

Those babies are completely dependent on their parents

for everything for the first few weeks of life.

'So, which of these two extremes did Utahraptor parents follow?

'A remarkable answer has emerged,

'with an intriguing discovery

'made in Mongolia's barren Gobi Desert.'

So, this specimen was discovered in the 1990s,

and it's a dinosaur that we call Citipati,

which is in the Oviraptor family, very closely related to Utahraptor.

What we're looking at here is the dinosaur is on its belly.

So, we're looking at it from behind, from the top,

from a sort of bird's-eye view.

And you can see from the posture that it's got its arms back,

protecting the eggs,

exactly like a bird would brood its eggs.

'This was a parent caring for its young

'to the bitter end.'

This dinosaur, in all likelihood,

was actually buried alive in a sandstorm

and may have actually taken the decision

to stay with its eggs and be buried in sand and mud,

rather than abandoning them.

And how fantastic of a parent is that?

Utahraptor is even more closely related to modern birds

than is Citipati.

So, in all likelihood, Utahraptor was a very good parent,

by the standards of the time.

It seems probable, then,

that, like their cousin the Oviraptor,

Utahraptor looked after their young from the moment the eggs were laid.

And presumably, this allowed them

to form close family groups that could hunt together.

By the... Heh! By the look of these two,

they'll be calling into action those parenting skills quite soon.

They're getting on awfully well.

'We won't get to see that ourselves, though,

'because it's time to leave

'this fascinating chapter of dinosaur history behind us.

'The Cretaceous has so far produced

'some radically different kinds of dinosaurs,

'from the plant-eating iguanodontids,

'with their vicious thumb spikes...

'..to the intelligent, speedy and ruthless raptors.

'Large and small.'

But in 40 million years' time,

dinosaur evolution is about to throw up a brand-new predator

that will make the Utahraptor look like a pussycat.

T Rex.

ROARING