Attenborough and the Giant Dinosaur Page #4

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to get other vegetation.

What about that?

This enormous reach would have saved

our titanosaur a lot of energy.

It only needed to move its neck to feed,

not its whole body.

But how did it eat enough of this

poor-quality food to survive?

Elephants face a similar challenge today.

An elephant can collect

and chew about 130 kilos -

that's 300 pounds of vegetation in a day.

But our titanosaur could have

eaten five times that amount.

It's been estimated that a large

titanosaur would eat enough

plant material to fill

a skip in a single day.

So how did they digest it all?

Elephants solved the

problem by giving their food

long preparatory chews but

titanosaurs didn't bother.

They simply gathered

leaves by nipping them off

and then swallowing them whole.

But that in turn would mean

that they needed a bigger

and longer gut to digest

all that unchewed food.

And it might well have taken ten days

for food to pass through their system.

A bigger gut needs a bigger body so

titanosaurs grew bigger and bigger

until they approached the limits

of what their bones could support.

Two years after the dig began,

a strange cargo arrives,

having made a 7,000 mile journey from Canada.

Dozens of packing cases later

and all the bones are

finally in Diego's warehouse.

Assembling the skeleton can finally begin.

The 3-D data used to make the

skeleton has also been used

to create a computer model.

It means I can get a preview

of what the final skeleton will look like.

The first thing is these very,

very lovely legs.

If we turn it around,

they are very, very column-like

and this is like elephants

but interestingly this titanosaur

had slightly splayed legs,

at an angle of about five degrees

and this slight change would have

really increased the ability

to take all that extra weight.

Can you see the splay because of the joint or

- because of the shape of the bone?

- A bit of both.

You can tell from the shape of

the bone and from where certain

parts of the bones form and how

they sit and then how the bones fit

with one another you can really tell

how it would have sat in real life.

Another thing you can see is a very,

very long neck.

And we just found out that

ours had 15 bones in its neck.

Interestingly, some of them were

five or six times longer than

they were wide.

These incredibly long vertebrae

and there's lots of them.

Why does it have such a long tail?

Well, a couple of reasons.

If you've got an animal this big with

a neck this long,

the last thing you want to be is top-heavy.

And research has just shown

that the centre of gravity

in this animal was somewhere right

in the middle of the chest cavity.

So the heavy tail counterbalances

the exceedingly long neck.

But judging from the size

of the muscle attachments,

the tail was also immensely strong.

It had huge muscles from around

here right down to about a third

of the way down the tail,

somewhere around here.

- So that would be solid flesh?

- Yep, muscle tissue, other tissue,

ligaments, tendons.

Do you think they might have fought with it?

- Possibly.

- Thrashing it about?

It could've been used as a defence mechanism

so you're walking up to that as a predator,

the last thing you

- want to be is on the receiving end.

- Don't put me into it!

Yeah.

The long and painstaking examination

of the backbone has now borne fruit

and Ben has got some important news.

This is a vertebrae here from

right high up in the back,

right near the shoulder blades.

And the most important thing is

this little ridge that ends in this

big lump and this is only found

in this particular dinosaur

so from that and a few

other physical differences,

we think we have got a brand-new,

exciting species.

So our titanosaur is not only a giant,

it is indeed a new species of dinosaur.

Examining the spinal bones also

reveal something about how it coped

with life as a giant.

This is where the spinal

cord would have passed.

- So this hole straight through here?

- Mm-hm.

The whole nerve centre, as it were,

- the cable carrying all the nerves.

- From the base of the tail

- right to the skull.

- It's very small. - It is, yeah. - Ours is what?

- About thumb width.

- So it's not all that much bigger. - No.

This cord was well over 100 feet long.

It would have taken about a

second for a nerve impulse

to go from its tail to its brain.

And what's more,

the spine has revealed another surprise.

It is full of holes,

rather like a Swiss cheese.

The neck bones of titanosaurs

contain so many holes

and spaces that they

weighed around 35% less than

they would have done had

they been made of solid bone.

The leg bones of modern

birds are much the same.

And those spaces serve another

very important function.

They contained air sacs.

These air sacs were connected with the lungs.

So what was their function

and how did they work?

They occupied much of the chest

and ran along the whole length

of the body along the backbone

to the 17-metre-long neck

and then to the head.

It's thought the balloon-like sacs

had thin but strong membranes.

These sacs acted like bellows,

forcing air into the lungs.

When we breathe in,

air flows down into our lungs,

oxygen is absorbed in exchange

for carbon dioxide which is then

got rid of when we breathe out.

The air sac system is very much more

complex but very much more efficient.

It enabled a titanosaur to

take in oxygen continuously,

not just when breathing in

but also when breathing out.

Our titanosaur wasn't the

only giant living around here.

ROARING:

This was a dangerous world,

where meat-eaters were giants too.

New evidence from the dig site

shows that carnivorous dinosaurs

were here as well.

So these are some of the over 80

teeth we found on the dig site.

And you can feel how sharp they are.

- Oh, yes, it's serrated, just like a shark's tooth, in fact.

- Absolutely.

They actually belong to a family

known as a shark-toothed dinosaurs.

We can identify the teeth

at the family level.

We know of one species that

belonged to that family,

it's called Tyrannotitan chubutensis.

- Tyrannotitan?

- Yeah.

- That means a ferocious giant, ferocious beast.

- Exactly. - Good name.

Yeah. Chubutensis is because

of the area it comes from?

Yes, this is the Chubut province.

Great.

Tyrannotitan must have been

a ferocious-looking beast.

With large eyes, sharp, flesh-eating teeth...

..and strong legs, it was a fast,

alert, meat-eating dinosaur.

- And it was as big as T Rex.

- Really? Not as famous.

- Not as famous.

- Tell that to Hollywood.

I have some bones over there

I would like to show you.

So this is one of the tail

vertebrae we found at the dig site.

There's something really interesting here.

- You can see this groove?

- Mmm.

Well, this groove was probably a bite mark

- made by one of the carnivores.

- By one of these teeth?

- Right.

- So it was... What do you mean? Like that?

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