Attenborough and the Giant Dinosaur Page #5

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or reds and oranges,

on the toenails of Melvin's

foot indicating high pressure.

And then some cooler colours

back towards the heel pad

in the greens and light blue.

That's low pressure.

So elephants are supporting most

of their weight on their toenails.

That pressure gets transmitted

up to their toe bones

and then up to their wrists

and ankles and so forth.

John's analysis suggests

that our titanosaur's legs,

like those of an elephant,

were placed vertically beneath the

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!

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