National Geographic: The Fox and the Shark Page #5

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down current from the vessel.

Any sharks in the area will find the

invitation very attractive.

Marine scientists from the University

of Adelaide want to test

the strength of a great white's bite,

and to identify the telltale sings of

shark attack for forensic purposes

a grisly but necessary study.

The sharks must be induced to bite a

specifically designed pressure plate.

First, they need to be worked

into a biting mood.

Ready now?

Okay, drop her in, Andy.

Now that the shark has the idea,

he gets his tuna on a plate.

Keep it in the air anyway,

because he's a bit cranky!

Running tests on the great white sharks

in the wild is always unpredictable.

We should have an impression on plate!

The plate is designed to measure

pounds of pressure per square inch.

That is amazing.

We're looking at the test strip

now and that looks as if...

This one is 500 kilograms,

One thousand pounds.

That one's more than 1, 000 pounds.

A thousand pounds per square inch

enough to puncture metal plating.

But what exactly is it that draws

a great white and prompts it to bite?

Is it the smell of prey,

or the sight of it,

or the vibrations it

sends through the water?

That's a crucial question for divers

so Rodney helps set up

another experiment.

What I hope to do here is

to really work out

whether the great white sharks

are interested in humans,

whether they can actually see

that there's an unseen shield there,

whether they may be

interested in fish or sound

Just to see

what they are interested in.

They swim around and around so many

times the cages without biting

and haven't had any true results.

I n order to test sight,

Rodney will use a cage of quarter inch

Lexan plastic to give the sharks

a clear view of his shape.

An underwater speaker

will test for sound,

broadcasting low frequency vibrations

to simulate the vibrations

made by moving prey.

A thawed tune will provide scent.

Will the sharks show

any clear preference?

Which one will attract them the most?

The adrenalin that rushes in you

as you go down there

and as the shark comes in

when you're in the Lexan tube

gives you a real rush

that excitement all over again.

It's like the first time

in my shark cages.

It's exciting and my heart you can

feel it a little higher

in you beating a little faster

as you realize that

you are part of an experiment,

that the sharks don't

really know whether or not

they can get at you or not.

It was quite unnerving really,

because I felt like I was naked

in the middle of the street in the

shop window with everything exposed...

Again and again, the circling

sharks pass Rodney by,

and return to the source

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