Attenborough and the Giant Dinosaur Page #3

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body like strong, massive columns.

This arrangement transmits

the weight to the toes

and then spreads the force,

using fatty pads in the back feet,

as shock absorbers.

But our titanosaur had one other

adaptation to help them walk -

one that elephants lack.

A clue to this can be seen

on the giant thighbone.

- How's it going?

- Good, good.

Ben Garrod specialises in

reconstructing skeletons

and he's joining the team to

look at the bones in detail.

Marks on them show clearly

where the muscles were attached.

- That's halfway down the femur, isn't it, that big lump there...

- Yes.

..for these massive muscle and,

I guess, tendon attachments?

This lump is where a huge muscle

was attached to the femur.

The other end of this muscle

was connected to bones

like these in the tail.

It's this connection that

helped our dinosaur to walk.

They've got so much strength

and so much rigidity up there.

They actually used their tails to help move,

to help their propulsion.

- So they had massive muscles and tendons from...

- Help...?

Yes, so the movement of the tail

actually pulled the hind legs

backwards and then raised them forwards.

Oh, I see.

I must try that sometime!

LAUGHTER:

The largest lizard alive today,

the Komodo dragon,

has a similar adaptation.

The swing of their tail helps their

back legs move more efficiently.

Of course, our dinosaur was different,

not least because it

weighed over 500 times more.

And that makes John Hutchinson

suspect that it would have

had to deal with another problem -

one also faced by passengers

on long-haul flights.

Pressure in the legs of big

animals is a really big problem.

If blood stays down there too long,

it's going to pool and clot.

Much like airline socks that humans use,

large animals,

again and again,

have evolved very thick elastic skin

around their lower limb that helps

to keep that pressure very high.

Actually, I can empathise.

I have to wear those same kind

of stockings to get my blood

back up my long legs!

Time to thank our helpful elephant.

You're a lovely thing. Yes, you...

Oh, you want one! OK, in you go.

Thanks. Thanks, pal.

That's all I've got!

A giant animal like an elephant

also needs a huge heart to pump

blood around its body.

And so did our titanosaur.

Its heart must have been immense.

From our new, detailed knowledge

of the skeleton, John Hutchinson

has calculated that it was more

than six feet in circumference.

It probably weighed 230 kilos

and would have had to shift 90

litres of blood with a single beat.

There's one!

And it would have had to repeat

that beat every five seconds.

HEART BEATS:

There it goes again.

Weighing more than three grown men,

it would have been extraordinarily powerful.

And in order to pump blood

around the body at high pressure

and then into the delicate

lungs at a lower pressure,

it's thought that our titanosaur's

heart had four chambers -

more like that of a bird than a reptile.

So, a powerful heart pumped the

blood to the extremities of the body,

but how did the blood get back?

As in an elephant,

a combination of fatty footpads

and tight skin are thought to have

forced the blood from its legs...

..all the way back to its heart.

Toronto, Canada, and the world's

biggest dinosaur-making factory.

The team is building a life-size

skeleton of this vast creature

to be unveiled in Diego's warehouse

in Argentina in six months' time.

First, they have to turn all the

information from the 3-D scans

into each individual bone.

State-of-the-art robots

carve moulds from polystyrene

so that the bones can be cast in fibreglass.

Up until now, the fossil bones

have been the main focus of the dig

but the rock that surrounds the fossils

also holds important information.

The nature of the layers of rock in

which these fossils lie can tell us

a great deal about how they got to be

where they are and how old they are.

Some of these layers are

volcanic ash which must have come

from a volcano erupting every now and

then somewhere in the neighbourhood.

And this ash around the bones can

tell us how old the fossils are.

Scientists worked out that all these fossils

dated from the Cretaceous period

but better than that,

they dated them precisely

to 101.6 million years old.

By a detailed forensic examination

and comparisons with living creatures,

the team have deduced a great deal

about the life of our titanosaur.

We now know when it lived, how big it was,

how it moved and what its

young might have looked like.

We've even calculated its heart rate.

In an investigation of this scale,

sometimes the most important

information comes not from

the most eye-catching evidence

but from quite tiny details.

Here is something that I really hoped

the excavation was going to find.

It's a tooth.

And it's tiny compared with

the size of the huge animals

from which it came.

Teeth can tell you a huge

amount about an animal.

And if you look at the tip,

you can see that it has been

worn into two facets on either side.

And that tells us that this tooth

engaged with the teeth on the other

side in an alternate way like that,

not head-on but one on either side.

So this animal, like a pair of scissors,

just nipped off the vegetation

on which it was feeding.

Enormous though it was,

just nipped off little leaves

and here are fossils

of some of the different kinds of

plants on which it might have fed...

..cycads, ferns and conifers.

One thing these plants have in common

is that they're all very

fibrous and hard to digest.

To get enough nutrients

from such poor quality foods

our titanosaur would have had

to eat them in vast quantities.

A descendent of one of these plants

still grows in Patagonia today.

200 million years ago when South America,

Australia

and Antarctica were all

joined together to form

a supercontinent called Gondwana,

a particular kind of

vegetation was dominant -

they were conifers.

They continued to survive

to 100 million years ago

when our titanosaurs were

roaming the land and a few still

survive today. Here in the foothills

of the Andes is one of them.

The monkey puzzle tree called araucaria.

Trees, like araucaria,

show that the dinosaurs

must have had another problem.

These conifers,

apart from being poor-quality fodder,

can grow to over 130 feet in height.

They would have been out of reach for

many animals but not our titanosaur.

Here, boys, come on.

It's pretty clear why a long neck

is useful for a land-living animal.

It enables it to reach vegetation

which is growing high up

at the top trees that other

ground-based animals couldn't reach

and it must have been much

the same for titanosaur,

except we know from the fossils

that titanosaur's neck was

very, very much longer.

And that enabled it to sweep

its head in a great wide arc

and even to reach between two

tree trunks that happened to be

growing close together

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