All language subtitles for Dinosaur.with.Stephen.Fry.S01E03.1080p.AMZN.WEB-DL.DDP2.0.H.264-RAWR_track4_[eng]

'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.

Mind you...

You never know.

ROARS

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.

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 a
dazzling and bizarre array of
forms.

To become giants.

ROARS

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.

For millions of years,
dinosaurs ruled the Earth.

And during their reign,
shifting continents and
changing climates

allowed many different species
to evolve.

Last time, I was in the
Cretaceous,

one of the hottest times in the
history of life on Earth.

The climate was ten degrees
warmer than today.

The perfect conditions
for the infamous raptors

to hunt giant grazers,
like Iguanodontes.

Tonight, I'm coming closer to
home,

to a period near the end
of the dinosaurs' reign.

And they've saved their
A-listers for last.

ROARS

For this period is ruled over

by some of the most chilling,
awe-inspiring, and enigmatic
animals

that have ever lived.

We've arrived at a key stage
in dinosaur history,

the moment that evolution
produces

the most terrifying killer
ever to stalk the Earth.

It's 68 million years ago.

We're in the era known
as the Late Cretaceous.

The dinosaurs' reign still has
another two million years to
run.

They are thriving.

This landscape around me

is a place you might nowadays
call North America.

And if you look carefully
enough,

this world is starting to
appear a little more familiar
than before.

Flowering plants have taken
over,

fuelling an explosion
in insect life.

And amid the conifers,

we can see trees
that we'd know today,

like maples and oaks.

So much for the plant life,

but the animals of this age
are far from familiar.

Oh, and look, there, at the
water.

One of the most iconic species
of the era.

The magnificent three-horned
Triceratops.

There's a group of them
enjoying a pause for some
water.

And over there, that
extraordinary-looking creature

is not actually a dinosaur at
all,

but one of their flying cousins
known as a pterosaur.

They look so ungainly, don't
they?

Carting around those huge wings
made of skin.

But if you were to see one
in... There, like that, there!

See? They're so graceful
when they're in the air.

ROARS

Something's spooked them.

And I don't think it's me.

LOW GROWLING

ROARS

This is the most fearsome
dinosaur of them all,

the Tyrannosaurus rex.

Its name, actually, is doubly
royal.

"Tyrannus" is Greek for king,
and "rex" is Latin for king.

You have to say, he really does
look

very much like
the ruler of this place.

A truly formidable beast.

It's 12 metres in length
and four metres in height,

and weighs in at eight tonnes.

ROARS

He's basically a double-decker
bus on legs.

But with sharper teeth.

The product of millions of
years of evolution.

But at just 68 million years
BC,

he actually lives closer in
time to the iPhone

than he does to the
Diplodocuses of the Jurassic
era.

Since their time, a quarter
of a billion years in the past,

the giant supercontinent of
Pangea has been gradually
splitting apart.

As it split,

it isolated distinct
populations of dinosaurs

in different corners of the
world.

And it's this isolation that
allowed them to diversify.

In what is today China,

68 million years ago, we find
the feathered and beaked
Oviraptor.

In Russia, the Olorotitan
ruled, with its colourful head
crest.

And in South America,
the giant Argentinosaurus.

Weighing up to 100 tonnes,

it's one of the largest animals
the world has ever seen.

T. rex fossils
have only ever been found

in what is now North America.

At the time, the continent
itself was split in half

by a vast inland sea.

And it's on the western island
where our T. rex lives.

And it is not on its own.

Slightly terrifyingly,
it's estimated

that at any one given time,

20,000 of these T. rexes
were roaming around.

That means that
over 2.5 billion T. rexes

once walked the Earth.

That's roughly the population

of Europe, North America,
and Africa combined.

Let's take a careful look,
shall we?

HE GIGGLES
Those arms are frankly tiny.

They look really silly.
I wonder what they're for.

ROARS

All right, all right.

Clearly touched a nerve there.

I should imagine those huge
hind legs do most of the
shifting around.

And they also act as a kind
of a balancing point

between the bulk of the body
and that huge sweeping tail.

And then
there's the extraordinary head.

Just packed with teeth,

which I can imagine would do
a serious amount of damage.

But there is something rather
curious about those teeth.

If we compare him

to our Jurassic era predator
the Allosaurus,

those teeth
are really thin and sharp,

perfect for slicing through
meat, like steak knives.

They were ideal for gouging out
great lumps of flesh

like a meat cleaver,

thanks to Allosaurus' amazing
gaping mouth.

But T. rexes are much thicker
and rounder,

ideal for heavy-duty crunching.

It's clearly evolved to eat
meat,

with its piercing teeth
and strong jaws.

Which raises a question.

Was he better suited
not for killing live prey

but for feeding off dead
bodies?

Clues could lie in the
modern-day cousins of
Tyrannosaurus,

vultures.

Vultures rely on strong,
dexterous muscles in their
necks

when they tear flesh off bone.

The same muscles are found
in our T. rex.

And they're not the only
similarity.

Vultures and T. rex also have
an S shape to their necks,

which provides leverage

when ripping back
to tear off chunks of meat.

They also share sharp
versatile talons

to grip on their prey.

So, it seems our king of beasts
was perfectly built for
scavenging.

But really, was T. rex
not the hunter/killer

certain movies have led us
to believe?

To help me find out is one of
the world's leading dinosaur
experts,

Dr David Hone, from Queen Mary
University of London.

Hello, David.

My good... Oh, dear, oh, dear.

Mind you, none of us look our
best

when we're tearing into our
dinners, do we?

I mean, this is a dead
Triceratops. So it's
scavenging? Yes.

That's not very regal.

They are scavengers, but they
were also predators, too.

So, like almost all large
carnivores,

they were killing things
actively

as well as taking whatever was
available if they found it.

And of course,
so many modern species

are both predators and
scavengers.

So, hyenas are always
the skulking scavenger,

but actually, they predate
most of their prey.

And people think of lions
as the king of beasts,

that kills everything,

and actually, they're very
adept at stealing food off
hyenas.

Tyrannosaurs and Tyrannosaurus
has particularly strong, thick
teeth,

and an extremely powerful bite,

and they're capable of biting
through even very thick bone.

But actually, at the front,
they have this little row

of actually very small
and flattened teeth,

and what they're actually doing

is a form of feeding
called scrape feeding.

They're literally pushing the
teeth down onto the bone and
pulling back.

Yes, we've got some evidence of
that on a fossilised
Triceratops bone,

where you can see bite marks
left by a scavenging
Tyrannosaur.

We find these long rows
of parallel stripes,

only on areas where the muscles
attach to bone.

So they're very carefully
feeding on just some areas,

and just stripping the muscle
off to eat it.

Oh, I've done that!

We do it with biscuits. Yeah.
Take the top off and scrape it
away.

Exactly what they're doing.
My heavens.

T. rex is clearly
an expert scavenger,

skilled at husking meat from
bone.

But he is undoubtedly
interested in live flesh, too.

And if I hang around long
enough, we might be able to see

just what kind of a hunter
T. rex is.

I've travelled back in time to
a magical and mysterious world,

on the western shores
of a vast inland sea

in a place you'd call today
North America.

Home to some of the most iconic
dinosaurs of all time.

We're in the Late Cretaceous
period,

and we've been on the trail of
the most feared predator, T.
rex.

This one has been scavenging
an old carcass,

but just now,
he's picked up the scent

of something far more
appetising.

Fresh meat.

This is one of the flying
cousins of the dinosaurs, a
pterosaur.

No doubt there's plenty of
juicy meat on those flying
muscles.

ROARS

Ha! What an incredible sight.

That was Quetzalcoatlus, the
largest ever of the pterosaurs.

He may have looked a bit
ungainly on the ground,

but once he took to the air,
it was like a small plane,

and about the same size, too.

Pterosaurs like this

lived alongside the dinosaurs
throughout their history.

But the mystery is,
how did they cheat gravity

and take to the air like that?

To answer that, we'll have to
travel even further back in
time.

170 million years ago,
in the late Jurassic period,

the Isle of Skye,
off the west coast of Scotland,

was a warm, tropical land,
dotted with lagoons.

Scroll forward to the present,

and a team
from Edinburgh University,

led by American palaeontologist
Professor Steve Brusatte,

made a record-breaking
discovery.

It was right here on this
stretch of coast on the Isle
of Skye

where we found Dearc,
the new species of pterosaur.

One of our students noticed
a jawbone and some teeth

protruding from that rock.

We took a look, and we saw
there was actually an entire
head in there.

And then, when we started
to take it out of the rock,

we realised that head
connected to a neck,

and connected to a body,
and connected to a skeleton.

Steve took that skeleton
back to the lab.

And it turned out to be
something very special indeed.

The fossil of a
170-million-year-old flying
monster.

The largest Jurassic pterosaur
ever found.

This is a really important
fossil.

I think it is a crown jewel
fossil for us here in
Scotland.

It's not just a beautiful
fossil.

Because it happens to be one
of the only really good
pterosaur skeletons

from the middle part of the
Jurassic anywhere in the
world.

Microscopic analysis
revealed this creature

to have not yet fully grown,

but it was already enormous.

There's one wing.

And here is the other,
more complete wing.

We have the upper arm bone,
the forearm bones.

And so if both wings
were stretched out,

this wingspan would have been
something like 2.5 metres.

And that's wider
than a king-size bed.

Steve's discovery
shows the giants of the sky

were around millions of years
earlier than first thought.

Up until we found this fossil,

we used to think that
pterosaurs never reached those
sizes

until tens of millions of years
later in the Cretaceous period.

The fossil even revealed a
secret as to how they flew.

A secret that can be counted
on just one finger.

I think the most beautiful
part of the fossil is the
little hand.

And we have three little
fingers.

Each one has a very sharp
hooked claw on the end.

And then a much bigger
fourth finger, the ring finger.

And it's that one finger
that anchored the wing.

And the wings of pterosaurs
were a giant sail of skin.

So very different from the
wings of birds or bats.

Modern-day birds have wings
with feathers attached to
bones.

Bats' four limbs form webbed
wings,

and to fly, they flap all four
spread-out fingers.

But the pterosaur used just
that extended ring finger,

acting as a mast,

that stretched along
the leading edge of the wing.

And that finger holds the
answer

to how anything so massive
could stay in the air.

If I were to look at my ring
finger, say in an x-ray,

it would be really solid
inside.

But not pterosaurs.

The bone is basically hollow.

You can see the walls of bone
are pretty thin,

and the middle would have just
been completely full of air.

And in fact, that's true of
almost the entire pterosaur
skeleton.

These animals were big,
but they were featherweight,

and that helped them stay aloft
when they were flying.

So, hollow bones allowed
pterosaurs to keep their weight
down,

and grow large,

and they continued to grow in
size right up to the time I'm
now in,

in the Late Cretaceous.

By then, Quetzalcoatlus, a
pterosaur the height of a
giraffe,

had become the largest animal
that has ever taken to the
skies.

So, Quetzalcoatlus is one of
the most extraordinary animals

that has ever evolved

in the entire 4.5 billion year
history of the Earth.

This was a reptile that was
the size of a fighter jet.

Its wingspan
was over ten metres wide.

It's the biggest thing
that has ever flown

in the entire history of life,
as far as we know.

I mean, you'd have to say,

that is so impressive when it's
on the ground as well.

I mean, it's huge.

I believe 20 feet,
something like that?

About the size of a giraffe
in height?Yep.

Amazing creature.
Absolutely extraordinary.

But how does something like
that actually take off?

First of all, an animal this
size

is actually only in the realms
of 250, 300 kilos.

Enormous, but a giraffe that
size is a tonne.

So not that heavy,
for that wingspan.

And secondly,
birds take off with their legs.

So they actually jump with
their legs, and then start
flapping.

So it's a spring?
Yes.

But they're gonna take off
with just their forelimbs.

Their wing muscles, which they
already use for flapping,

and are therefore extremely
strong,

it's gonna use to launch
off the ground.

So it's jumping
with its big muscles.

Let's see if I can make it show
us.

HE CLAPS
Fly, my pretty!

CLAPPING

Well, that's what I call
a successful take-off.

Extraordinary.

Well, it seems our T. rex
didn't have much chance

of catching our Quetzalcoatlus.

And to be honest, it wouldn't
really have been a fair fight,
anyway.

But T. rex wasn't the only
predator around the world at
this time,

and each was supremely built
for its own choice of prey.

In prehistoric North Africa,

Spinosaurus uses its long snout
to pluck fish from coastal
shores.

In ancient Mongolia,

Saurornithoides
has excellent eyesight

to spot small mammals scurrying
around in its desert home.

And in Argentina, Mapusaurus
hunted massive sauropods

in wide-open plains
by working together in packs.

And here in North America,

our T. rex is eyeing up
something a little more
grounded.

A juicy Triceratops.

At least it can't take flight
and escape into the air.

Even so, to track down, catch,

and kill
one of these armoured beasts

is going to be far from easy.

So, how did T. rex choose its
prey?

That is something Professor
Roger Benson of Oxford
University

is trying to find out.

He's going inside the mind of a
very famous T. rex called Stan

to get a sense of how
it sensed the world around it.

Stan was excavated in 1992
from South Dakota, in America.

His bones were sold in 2020 for
an eye-watering $32 million.

Making Stan not just the
best-preserved T. rex ever
found,

but the most expensive dinosaur
in the world.

This is a full-sized replica
of Stan's skull.

One of the things
I'm really interested in

is how we can use information
from the bones

to understand the sense organs
of this animal.

Sense organs don't fossilise
well,

so Roger has just the skull to
study for clues

as to how T. rex might have
used its sight, hearing, and
smell.

This is the eye socket.

About five times as wide
as a human socket.

And it could have housed
a potentially massive eyeball.

An eye socket of this size
has potential

to give T. rex
really excellent vision.

And one of the interesting
features of the eye sockets of
T. rex...

As you can see,
the skull is wide at the back,

it's narrow at the front.

And what this means is that
the eye would have looked
slightly forwards,

allowing it to focus on things
straight ahead of it,

and get some idea of depth.

And what that might tell us
is that T. rex might have been

a relatively effective
visual predator.

So it had good eyesight.

But what other super sense
could help Stan hunt?

Clues could lie
in the animal's brain.

So, Roger scanned the inside
of Stan's skull

and used a state-of-the-art
3D printer

to build a life-size,
three-dimensional

replica Tyrannosaur brain.

It looks like a kind
of wacky alien spider,

but in fact, all of these
structures coming out of the
side,

those are nerves, blood
vessels,

and other structures that
emerge from around the brain.

It may be small,
but this life-sized model brain

can shed light on how T. rex
sensed the world around it.

That way is forwards,
towards the snout.

That way is backwards,
towards the neck.

And one of the structures
we find at the front

are the olfactory bulbs,

the part of the brain that
processes information on
smell.

And there's really
no predatory dinosaur

that has proportionately
bigger olfactory bulb than T.
rex itself.

Which means T. rex
had the best sense of smell

of any dinosaur yet discovered.

And acute
20/20 forward-facing vision.

All the super senses needed
to see or sniff out prey,

day or night.

Which raises the question, was
T. rex - this fearsome predator
-

actually a night-time hunter?

Well, one thing you can say
about the Late Cretaceous

is there's no spill pollution

from street lighting or big
cities, is there?

But let's, erm...
Let's add our own light.

There. Now...

Whoa.

LOW GROWLING

There he is. Look at that.

And these super senses they
have,

they lead you to believe
that maybe he was nocturnal?

Yeah. I mean, that's one thing
that's really gonna help.

You don't need amazing eyesight
in the daylight.

Our eyesight's pretty good,

and yet their eyes
are massively bigger,

so they would operate very well
at night.

And then on top of that,

it's very hard to hide an
animal of this size.

I see what you mean. So they're
better disguised at night?Yeah.

So it's got
a superior sense of smell?

Yeah. A very good sense of
smell.

Again, that's useful in
daylight,

but it's gonna be more useful
at night when you can't see
that far.

Yeah. So again, we don't know
for sure,

but it indicates that it could
well be good in the darkness.

And as for their colouring,
do you think that's dark?

Well, those dark black stripes
on the body

would really help break up the
outline in low-light
conditions.

So a bit like a zebra?

Or, indeed, like a leopard,

or any sort of animal
with some kind of marking?

Spots and dapples, yeah.

Using shadow and highlights
to disguise its outline.

It's extraordinary, isn't it?

I don't really think it's much
of a kind of stealth creature.

No, it never will be.
But an incremental advantage,

if it allows you
to get ten metres closer,

that could be the difference
between getting a meal and not.

Then you spring and you pounce.
Yeah.

Well, before he springs
and pounces on us,

I'm gonna turn the light down.

Ooh, I think he's found a
target.

He may have the element of
surprise.

But does he have the pace
to run down his prey?

ROARING

I'm in the Cretaceous period,

on a nocturnal hunt

with one of the most
fearsome predators of all time.

T. rex is equipped
with fantastic senses

to help him navigate at night.

Smell, hearing, and eyesight.

And with a bulk like that,
darkness is the perfect cover.

He's found a likely target
over there,

a juicy-looking Triceratops.

But will he be quick enough
to catch his prey?

In fact, how can we possibly
know how fast this,

the largest animal ever on two
legs, could really move?

Evidence may lie
with a distant descendant

of this king of dinosaurs,

the ostrich.

And they do have
a surprising likeness.

This is an ostrich foot.

This is a Tyrannosaurus rex
foot.

They're very, very similar.
If we take the ostrich toe bone

and hold it next
to the same bone in T. rex,

you can see just how similar
they are.

The feet are fundamentally
built out of the same building
blocks.

Palaeontologist Dr Peter
Falkingham of Liverpool John
Moores University

is an expert on dinosaur
locomotion.

To him, the key to
understanding how fast they
could run

lies in how they support their
weight in the first place.

ROARS

So one of the first things
you can see here

is that the T. rex bone,

while it's almost the same
shape as the ostrich bone,

one difference is this divot
on the T. rex bone.

And that's where the tendons
would have attached.

And those tendons would
help brace the toe,

absorb impacts from
the large mass of the T. rex.

So, shock-absorbing ligaments
for support.

But what about moving?

With a top speed
of 70 kilometres per hour,

greater than a racehorse,

the ostrich is the fastest
and largest two-legged animal

alive today.

To understand how they run,
Peter films them in ultrahigh
speed.

I'll be able to look
at really fast motion

and slow it down and be able
to really quantify the motion.

You can see both feet are off
the ground at the same time.

That means it's a run, not a
walk.

And we can pause that.

And if we start tracking,
it will follow that.

And you can see quite clearly
as it's pushing off,

that limb is very, very
straight.

For an ostrich to support
its weight when running,

it keeps its legs
as straight as possible,

and positioned directly under
the main mass of its body.

So, what you can see
as the video plays

is that the ostrich is swinging
its leg from the knee.

Now, an ostrich is about 100
kilos.

A T. rex is eight tonnes.

So that's really gonna have to
try

and keep its limbs as straight
as it can to support its
weight.

By applying these ostrich data
to a computer model,

Peter can simulate
how T. rex ran, too.

So this model is showing
reconstructed muscle positions

on T. rex's skeleton.

And you fire those muscles,

and you figure out how the
bones must have moved

to support the weight.

So you can see the feet,
they're barely off the ground
together,

so it's only just a run.

And you can see that the legs
are straight.

They're straighter than the
ostrich.

T. rex really is pushing the
limits of how large you can
get

and still support yourself
on two legs.

So it's no surprise that it's
finding it difficult to run
fast.

So, how fast could T. rex go?

ten, 15, 20 miles an hour,
tops.

For comparison, an Olympic
sprinter would be 27 miles an
hour.

So it's not as fast
as the fastest human,

but it's probably faster than
me.

It looks like we might be about
to see that running speed in
action.

Our T. rex is on high alert.

He's spotted a lone Triceratops
over there.

This could be an opportunity
to see how fast he can go.

And I've asked dinosaur expert
David Hone

to provide a post-match
analysis of how the hunt goes
down.

ROARING

STEPHEN CHUCKLES

Well, a successful kill.

What were the tactics it uses
there against the Triceratops?

So it's gonna get in as close
as it can.

Though as we said, it's pretty
difficult at that kind of size.

But once it starts going,
basically, it's relying on
distance.

It's better over long distances

than pretty much anything else
that's out there.Oh.

And that's the usual way?

It's not about speed, like a
lion or a cheetah or something?

Yeah. They're not that fast.

I mean, animals at this kind
of scale...

It looks pretty quick,
cos of the size of them,

but they're not as fast
as you would think

for an animal
that's an active hunter.

But again, the scale of
everything,

the prey is relatively big and
slow as well.

And then when they get close,

obviously they're mostly
striking from behind anyway.

Yeah, it went for the back
of the animal.Yeah.

So, dinosaurs have, basically,

most of their big leg muscles

go from about halfway down the
thigh to about halfway down
the tail.

So that area is a single giant
block of muscle.

So any kind of bite in there

is immediately gonna cripple it
and stop it running.

But also, the blood loss and
shock, and the rest of it,

is going to be... Not fatal,
but it's not going anywhere.

So it rips into the sort of
rump of the Triceratops? Yeah.

Brought it down.

It's game over pretty much
at that point.

We've actually got
some more evidence here

that T. rex has been feeding.

And, indeed, going past
afterwards.

What on Earth! Well, it's what
you think it is.

It is, I'm going to use the
word, a turd.

It is. Erm...
This is what they produce.

And this is a genuine one?

It's not just a made-up idea,
is it?

I mean, obviously
it's not the real...

But is it like fossilised poo?
Yeah, it's based on one.

And actually, inset are broken
bit of bone from a young
dinosaur,

which is what we found
in Tyrannosaur,

preserved Tyrannosaur
coprolites.

Oh, so it would crunch up on
babies?

On junior?
They would indeed.

Mostly what they're eating
is youngsters.

But we can actually learn some
stuff about it from this,

because the very fact that the
bone has passed through,

if you looked at something
like a crocodile,

bone comes out almost as a
slurry.

The acid is so strong that the
bone basically dissolves.

It doesn't here.

And it's been through
a much bigger animal.

So its digestive power
is not some kind of...

It's not some kind of
superpower,

which I think some people
think it is.

It's a simpler tube, really?
Yeah.

But it's just going
for a more normal digestion,

rather than a super bone eater.

So again, that harks back

to it not being some kind
of specialist scavenger

that can dissolve bone and get
every last bit out of it.

Cos even the bones of babies
come through.

I think we've learned what we
can from this. I'll pop it
back.

Do that. Pop the turd back,
if you'd be so kind.

And then wash my hands.
Yeah!

So, we've amassed
some terrifying examples

of the power of those T. rex
jaws,

crunching through the bone
of a Triceratops.

And passing the remains
of baby dinosaurs in its waste.

But what would it be like to be
on the receiving end of that
bite?

The crocodile has the most
powerful bite of any animal
alive today.

Its over 1.5-tonne nip is
powerful enough to crush a
human skull.

But how strong was T. rex's
bite

compared to today's
world record-holder?

To find out, T. rex's fearsome
jaws are being brought back to
life

with this mechanical replica.

Capable of exerting the same
force as a T. rex jaw.

Operated by University College
London engineer

and dinosaur enthusiast
Dr Adam Wojcik,

and paleobiologist Andre Rowe.

I'm a big T. rex guy.

I've been studying a lot
of bite forces.

And T. rex's highest bite
forces

were generally around four
times as much

as the largest modern
crocodiles.

Which is quite scary,
when you think about it.

And obviously it's going
through a whole array of teeth,

you've probably got around
about 250kg of force per
tooth.

A T. rex could channel five
tonnes of pressure through its
teeth.

Now,that's gonna be pretty
destructive.

First up in that t.
rex jaw press, a cow skull.

CRACKING

Fantastic.

The bone has definitely
exploded.

It's kind of split.

You heard the noise there.
Quite the crack.

I have no doubt that T. rex
could have done this

to a large herbivorous dinosaur
back in its heyday.

And probably a lot more as
well.

Yeah, no doubt about that.

The bone is destroyed.

But this doesn't come close to
what a real T. rex was capable
of.

I think the next thing for us
to do

is test it on something
a little bit more chunky.

Without any dinosaur bodies
available to test today,

we're going to try something
designed to withstand being
crushed.

Andre, do you think on the
basis of this experiment,

T. rex could actually have
chewed its way through a brick?

Well, considering the bite
forces,

and the evidence we have
from our tests today,

I don't think that it's outside
of the question...Right.

..if we somehow brought bricks
back to the Late Cretaceous.

It would be quite a spectacle,
that's for sure.

Well, I've discovered
this incredible statistic

about its bite force,

that it's the greatest of any
animal that ever lived on
Earth.

Kind of overengineered.

Because you're talking about
the ability to crush bricks.

All it needs is a bone.

And these are avian bones,
some of them are hollow.

Some of them. But a lot of the
herbivores don't have that.

And so, of course, for the big
things like Triceratops,

if you want to break into them,

or break up the carcass
to be able to consume it,

then you're going to need
a comparable bite power

to get through the bones
of a huge animal.

ROARS

Ah, there's a second T. rex
approaching.

This could get interesting.

ROARS

I'm in a time near the end
of the dinosaurs' reign.

I've already seen the
scavenging ability of our
mighty T. rex.

And witnessed an incredible
fight with a Triceratops.

But it doesn't seem to be alone
in this prehistoric wilderness.

An outsider has just arrived
here in the Late Cretaceous
period.

At first, I thought
he was gonna fight our T. rex

over its fresh kill.

But now...
THEY ROAR

..I'm not so sure.

Because this dinosaur is, in
fact, a she.

Maybe we're about to witness
the more loving side of T. rex.

A bit of Tyrannosaurus sex,
if you like.

ROARS

Well, that was quick.

I wonder if dinosaur expert
David Hone

can shed any more light on how
we can possibly know anything

about how Tyrannosaurs really
mated.

Well, they can't be accused of
wasting time over the matter,

can they?
No, definitely not.

But that's pretty common.

A lot of modern animals

take seconds, really,
for this kind of thing.

We saw a bit of sort of
muzzling and nuzzling.

Do you think that was likely?
That they would rub their
noses?

Most animals go through some
form of courtship ritual,

even if it is only a few
seconds.

And we do at least have plenty
of birds

that go in for beak rubbing
and things like this.

There's even been
a specific suggestion

that Tyrannosaurs did this
with very sensitive lips.

That's a nice thought.

I suppose I can't help
mentioning that,

with all dinosaur coupling,
you feel the sheer size.

I mean, can the female
take the weight?

Well, presumably she would,

otherwise we wouldn't have had
dinosaurs for 160 million
years!

I wonder if the T. rex as well,

those tiny hands, are they
enough to help him cling on, as
it were?

I'm sure they helped a little
bit,

but I doubt that's what the
arms were functioning for.

Because otherwise the females
probably wouldn't have had
them.

And now?

Do they stay together and raise
their young as a couple?

Very probably.
It's likely that Mum at least,

and quite possibly both,

were engaged in looking after
the babies after they hatched.

As well as looking after the
eggs,

and guarding the nest
in the beginning.

Well, these two seem
to be getting on very well.

But when it comes to T. rexes,
that isn't always the case.

Dr David Gelsthorpe
at the Manchester Museum

is examining
the full-size replica of Stan,

the most complete and valuable
dinosaur yet discovered,

for clues as to just how
violent life was for this king
of beasts.

Stan probably wasn't fully
grown.

He was probably
about 20 or 30 years old.

He may be a youngster,

yet Stan bears marks
of how dangerous life was

in the Cretaceous.

There's a hole just up there.

It's quite a round circular
hole.

I've got a T. rex tooth.

And if you hold it up next
to the hole, it fits perfectly.

So this is really great
evidence

for another T. rex having
an encounter with Stan,

and the tooth going so far in

that it's actually made this
puncture wound in the scalp.

And there's more evidence
of sparring

further down the skeleton, too.

On the third vertebra back,

there's quite a sort of bulbous
knobbly piece of bone,

where the T. rex has had
some kind of injury.

The bone has grown around
this injury.

It very likely is evidence
of a fight.

There probably would have been
bigger and more aggressive T.
rexes

that were right at the top
of the food chain.

But he no doubt would have been
challenging his way to the top.

And our T. rex has been
in a few fights, too.

There are scars all over his
body,

showing that, well, he may be
a mean, killing machine,

but he faces his own dangers.

In the next episode,

we're going to see how T. rex
faced threats from the plant
eaters,

as creatures like Triceratops
used their formidable
defences...

..to fight back.

And as these creatures enjoy
the heyday of the Late
Cretaceous,

they are completely oblivious
to a warning sign in the sky.

That bright star is, in fact,
an asteroid.

And the extinction of the
dinosaurs

is hurtling towards
a devastating collision

which will change the course of
the history of life on planet
Earth.