Episode 1 Shark

Drop beneath the waves...

..and you'll discover another world.

Mysterious.

Unexplored.

A world ruled by strange,

fearsome creatures.

They're an ancient family

whose ancestors fought dinosaurs.

Today, they are every shape,

every size,

and hunt in every sea.

These are the ocean's greatest predators.

This is the world of the shark.

Off the coast of Cape Fear

are the wrecks of over 100 ships.

A unique place

where you can get closer than you may like

to one of the most frightening-looking sharks.

Ragged tooth sharks gather in these wrecks to feed.

They show all the characteristics of great ocean hunters.

A streamlined body,

and a muscular tail.

A mouth packed with teeth.

Teeth that are endlessly replaced.

A head crammed with sensors to detect their prey.

Their design is so successful,

it's barely changed in 400 million years.

The best place to see these perfect predators in action...

..is here,

the tip of South Africa.

A lone blacktip shark is drawn to a faint sound

far away in the distance.

A sound far too faint for human hearing.

She's not alone for long.

Other blacktips can hear the sound, too.

It's the greatest gathering of hunting sharks in the world.

Hundreds and hundreds of six-foot-long sharks,

all here because of this.

Ten million anchovies are swarming up the coast

on their annual migration.

Tiny and agile,

they easily out-manoeuvre a single shark.

But the blacktips work together.

Of all the sharks,

these are the masters of teamwork.

Some swim underneath the fish,

trapping them against the surface.

While others circle the shoal.

Herding them together.

And, when the moment is just right...

..the blacktips attack.

Striking from every angle,

the sharks cut off any escape route.

As the attack builds,

the fish crush together ever tighter.

Greedy gannets dive in,

getting a free meal from the blacktips' hard work.

The fish huddle at the surface.

But there's no way out.

The sea is filled with a snowstorm of fish scales.

And then these blacktips simply disappear into the blue.

Sharks belong to one huge extended family.

And every single family member shares certain key features.

Their skin is made from thousands of minute teeth coated with enamel.

Sharks don't have bones.

Instead, there's a skeleton of rubbery cartilage.

They all have a row of gill slits,

usually five along their side.

There are 510 species of shark.

The largest is a staggering 40 feet long.

The smallest could fit in the palm of your hand,

and it glows in the dark.

Some have heads shaped like a hammer.

Others like a chainsaw.

And there's one with a body so strange...

..it can hardly be seen at all.

This master of disguise

lives in the eastern seas of Indonesia.

Home to the world's richest coral reef.

More than 1,500 species of fish swim in these sunlit waters.

But in the shadows, something is lurking.

This is the tasselled wobbegong.

The greatest ambush hunter of all sharks.

The tassels on his chin look like pieces of coral,

breaking up his profile.

His skin is exquisitely camouflaged.

He lies motionless, staring at the fish.

His sharp eyes focus on a single spot in front of him...

..waiting for a victim to stray into range.

No luck here today.

Time to try somewhere else.

The wobbegong is a poor swimmer, but has a routine.

If one site isn't working, there are other places to set the trap.

The wobbegong's favourite hideout is the entrance to a cave.

The fish are wary and keep their distance.

But the wobbegong has a trick.

His tail is a lure that attracts his prey.

Waving it at the back of his cave,

it mimics a fish already swimming there.

So, it looks safe to enter.

Wrong.

Pressure sensitive cells on the wobbegong's head

detect the slightest movement.

As they come ever closer,

the wobbegong goes onto high alert.

It's behind you!

The strike is so fast,

the other fish never even saw the victim disappear.

In the blink of an eye...

..the fish is sucked into the mouth,

and straight into the stomach to be slowly dissolved and digested.

Wobbegongs may be the masters of patience...

..but other members of the shark family

are in rather more of a hurry.

The mako is the fastest shark in the world.

Think torpedo with teeth.

The tail is packed with muscle.

The body is sleek and streamlined.

It has a stabiliser on the side for cornering at speed.

Like all sharks, the skin is made from minuscule teeth,

but the mako's is specially textured to minimise drag.

Here in the open ocean, their dinner, tuna, is quick

so makos have to be even quicker.

To see just how fast they are takes a speedboat...

..towing a camera.

The shiny housing attracts the attention of all sorts of animals.

First to follow,

fur seals.

Their top speed is 10mph.

Twice as fast as an Olympic swimmer.

But there are faster creatures around.

A pod of common dolphins arrives.

With super streamlined bodies, their top speed is 20mph.

But, if the boat accelerates,

they, too, will drop away.

Then, at full speed,

a mako.

It can sprint at 30mph.

That's quicker than Usain Bolt.

Makos have been clocked at 46mph,

though no-one really knows their limit.

But it's faster than the speed boat.

Sharks have adapted to live in every ocean in the world.

Even here, where the ocean is frozen.

Under this Arctic ice lives one of the most mysterious sharks of all.

DOGS WHIMPER AND HOWL

For centuries, they were known only to the Inuit people.

They once caught sharks as food for their dogs.

Today, they use their skills

to help scientists find and track these sharks.

Greenland sharks live half a mile down

in the abyss.

In this twilight zone,

there is little to eat,

and the water is -1.

Only the salt stops it from freezing.

A Greenland shark's metabolism is set low to survive the cold.

He swims at just half a mile an hour,

but he could live for 200 years.

In his constant search for food,

he must emerge from the darkness,

and slowly, slowly,

swim to the surface.

Up in the light, it's a beautiful place.

But he cannot see it.

He is blind.

In these Arctic waters,

every Greenland shark has a copepod parasite attached to the eyeball.

This bizarre creature lives only on Greenland sharks,

gnawing away at the surface of his eye

until his world drops into shadows.

He finds his way through the darkness by smell.

If he picks up the scent of food, he could track it for miles.

Greenland sharks scavenge anything they can find.

A dead reindeer,

even a drowned polar bear.

Most times, his search for food at the surface finds nothing.

He drops down again,

blind and silent...

..and disappears back into the deep.

His is a long and lonely life.

It's not only Greenland sharks that live in the abyss.

The deep ocean hides other sharks that are even stranger.

Now, new technology and new cameras mean they can be found.

A team of Japanese scientists and cameramen

have spent four years exploring the abyss.

Over half a mile deep,

strange creatures appear,

feeding on the detritus that drifts down from life at the surface.

Either that,

or they feed on each other.

There are predators in the darkness.

A frilled shark catches prey by lunging forward like a snake,

snaring victims in its 200 teeth.

Their mouths open so wide

they can swallow prey more than half their size.

Their eyes have built-in image intensifiers

to detect the faintest glimpse of potential food.

Some sharks are so well adapted to life in the depths,

they don't rely on sight at all.

The goblin shark is a living fossil,

virtually unchanged for 100 million years.

The long snout works like a metal detector,

picking up the minute electro-magnetic field

given off by fish.

In the darkness, it drifts towards prey

until they're directly in front of its jaws.

The extra reach helps snatch the victim

and, down here, that can make all the difference.

Constant darkness and a pressure 100 times greater than at the surface

makes this a tough place to live.

But there's one species of shark

that lives somewhere even more challenging.

And it's in the most unexpected place.

The tropical seas of Australia's Great Barrier Reef.

14 species of shark live in these shallow waters.

Twice a day, conditions here change drastically.

And that's what the smallest shark on this reef

is waiting for.

Under two feet long,

an epaulette shark could be eaten by the bigger sharks if it's spotted.

So, while they're around, it stays well hidden.

It's waiting for the tide to go out.

And, on this part of the reef, when the tide turns,

it's like a plug has been pulled out.

A billion gallons of water pour away.

The bigger sharks retreat into deeper water.

The reef is left as a series of interconnected rock pools.

Perfect!

Now the epaulette has the reef all to itself.

The other rock pool creatures live in fear of this tiny tyrant.

Its sinuous body is ideal for crawling into crevices.

Its favourite dish is fresh crab.

But it's not all going the epaulette's way.

The tide keeps dropping.

What was once a pool quickly becomes just a puddle.

The scorching Australian sun is no place for a shark.

As the water finally drains away,

the epaulette is left high and dry.

No shark can breathe out of water.

But the epaulette shark has a trick.

By shutting down its organs one by one

it can cope without oxygen 60 times longer than a human.

And if necessary, it switches to survival strategy number two.

This is the only shark that can walk on land.

It heads towards the nearest water.

The fins have become prototype legs.

At last, the refreshing, cool sea.

This is a shark that can walk its way out of trouble.

Epaulettes aren't the only shark whose body shape has evolved

in surprising ways.

Thresher sharks have a tail that's the length of their body.

They use it as a whip, stunning their prey.

Basking sharks feed on plankton,

filtering vast quantities of sea water

through enormous modified gills.

Nurse sharks have a mouth like a vacuum cleaner.

Their favourite food is firmly hidden in its shell.

But one strong suck...

..and it's out.

A wide, hammer-shaped head helps this shark

detect prey hidden in the sand.

But some sharks have adapted,

not by changing their bodies...

..but by changing their behaviour.

At first sight, whitetip reef sharks don't seem like ferocious predators.

By day, local fish use their skins as a scratching post.

Young sea lions have fun harassing them.

But these sharks are simply biding their time...

..waiting for the perfect conditions to hunt.

As darkness falls, the tables begin to turn.

The whitetips change

from Dr Jekyll...

..into Mr Hyde.

Every available shelter and refuge is taken.

It's a bad idea to be caught in the open after curfew is called.

The whitetip pack use their sense of smell

to home in on the fish.

Hunting as one, they scour the reef,

inspecting every nook and crevice.

You can run,

or you can hide.

Either way, the pack will find you.

Because as they get close, another sense takes over.

Electricity.

All living creatures produce a small electrical field.

Sharks can detect even a few millionths of a volt.

The electricity from the beating heart of a frightened fish.

A struggling fish gives off low-frequency sounds

and that attracts other whitetips,

their hearing tuned to that particular pitch.

In the night, the mob rules.

It's a long wait until dawn.

At last, the sun starts to rise

and, like the flick of a switch,

the attack stops.

The advantage of darkness over,

the whitetips head back to rest.

It's safe for the fish to come out.

They spend the day lying on the seabed...

..if they're left in peace.

But, come the night, the whitetips again will rule the reef.

Sharks have been the ocean's greatest hunters

for 400 million years.

They mastered the seas

with patience and stealth.

Astonishing speed.

Agility and strength.

There is one shark above all others

that combines every single one of these skills,

plus a bit.

MUSIC: Baby Did A Bad, Bad Thing by Chris Isaak

The great white shark has it all.

Speed, strength, stealth.

And huge teeth.

It needs them.

Of all the sharks, it has the hardest prey to catch.

It hunts on the Cape of Storms,

Africa's wild south coast.

It specialises in hunting another predator.

One that is smart, aggressive and agile.

One that even eats small sharks.

Fur seals breed on the islands and feed in the rich waters.

This female has travelled hundreds of miles to be here...

..and she's hungry.

But she has competition.

Dozens of great whites have arrived,

all vying for the same food.

She needs to eat.

The seals gather in the safety of the kelp.

The seals need to reach the open ocean to feed.

To get there, they'll have to run...the gauntlet.

At first light, these seals gather together

and make a dash for it.

But the shark senses their movement

and she starts to track them.

Attacking a seal is dangerous.

Get it wrong and she could lose an eye.

She stays deep, stalking them.

If she's to make the kill,

surprise is everything.

She misses.

Now the advantage goes to the seals.

They scatter, but one has been injured.

The shark is stronger,

but the seal is far more agile.

The seal's strategy is to stay on her tail.

It's the one place it can't be caught.

Keep close and then make a sudden dash for it.

In this murky water, she loses sight of her target.

But the seal is wounded and she starts to follow the plume of blood.

It's a clean kill.

By shaking her head, she rips off chunks she can swallow.

She drops the seal to get a better grip.

But the blood is attracting other sharks.

Her hard-won meal has been taken.

BIRDS CRY

Outwitted and outmanoeuvred, she's wasted precious energy.

Great white sharks burn fuel faster than any other shark.

She must eat soon.

Another group of seals heads her way.

Leaping clear of the water at 20mph...

..the one-tonne shark catches a seal in mid air.

It's no wonder that of all the sharks

The great white is the most famous.

Sharks are the greatest predators in the ocean.

And the great white is the greatest predator of them all.

For two years, the BBC Shark team

travelled the globe to try and reveal sharks like never before.

By spending so much time observing them,

they hoped to show the true nature of sharks.

And that meant getting closer than ever to the ocean's

most impressive predators.

BIKE ENGINES PURR

Of all the places to find a shark, the Arctic was the most unexpected.

To film Greenland sharks means diving in sub-zero temperatures

in uncharted waters.

WIND HOWLS

It takes great expertise to cut a hole through ice

that's eight-feet thick.

Whenever you come out of the tent

and you see a hole cut in the ice,

and no other way out, and you look at it and you think

"Are we absolutely crazy? How cold is this going to be?"

Bits of you that are exposed on your face just, you know,

initially sting and they go numb pretty quickly.

But mentally, getting in is the hardest part.

Even with the latest thermal diving suits,

the crew have just 40 minutes in this freezing water.

We're just putting hot water in our gloves and our hood.

You cool down so quickly in there

that you've really got to go in warm cos, one thing's for sure,

you're not going to warm up when once you get in.

On the surface it's -20, but once in the water

it will feel even colder.

You go through this tiny little hole into a world

that is so completely different to what you see above.

It's like stepping off the planet.

The ice hole is the only exit to the surface.

If they lose their way, they'll be trapped.

There's small pinches and there's small spaces

so, definitely, in the forefront of your mind

is where you're going to be able to turn around to come back out.

So, you definitely take it cautiously and slowly.

Enduring these freezing temperatures,

they discover that the Greenland shark

is perfectly at home in this frozen world.

It certainly lives in a pretty hostile environment.

It's bizarre in many ways, and yet, so of its place.

But the clock is ticking for the crew.

Their body temperatures are dropping and,

what's worse, their air supply is beginning to freeze over.

It's time to get back to the ice hole.

Don't know if I can talk properly.

I actually can't because my lips are frozen.

They have some unique images of the Greenland shark,

but, to get all the shots they need, the Shark team will endure

another 13 dives under the ice.

The team's aim was to film sharks in every ocean habitat -

even man-made ones.

It's called the graveyard of the Atlantic.

Over 100 wrecks off the coast of North Carolina.

Ragged tooth sharks gather here to feed.

An opportunity to get eye-to-eye with a fearsome-looking shark.

-Rachel Butler is in charge of dive safety.

-I'm ready.

-Oxygen analysed?

-Yep, O2 analysed.

Oxygen supply pressure?

'It's really important that we do these checks because you can't

'afford for anything to go wrong if you're trapped inside a shipwreck.'

It's a long way down.

When you're inside a shipwreck with 50 sharks,

it does make you think a little bit because they look so fierce -

especially as they're swimming right over you.

It turns out the sharks are simply not interested in the film crew.

The sharks are very misunderstood, very misunderstood.

They're actually more scared of us than we are of them.

-They are, they are.

-I nearly touched one and it just went - kercheeeww! -

swam fast away from me. I was thinking,

"I'm the one that's supposed to be scared of you!"

But there's one shark where extreme caution is required -

the great white.

WAVES CRASH

To film great white sharks, the team travel

to their prime hunting ground, the coast of South Africa.

One of their goals is to film the sharks underwater

as they prepare to hunt.

Great whites attack seals at the surface,

making it the danger zone for any diver -

so novel precautions are taken.

I've rigged a rear-view mirror on my camera housing here.

White sharks are notorious ambush predators,

so they always seem to come from behind you.

If the light's blinding and you look into it you can't see anything -

that's where they're going to come from.

Andy needs a cage to get to the safety of the seabed.

You're diving around seal colonies where they're hunting.

You'd be stupid not be cautious.

He's able to get a unique perspective from inside the kelp.

As the shark's attention is focused on the seals,

it should ignore Andy.

They're not out to get us.

They're professional predators that eat seals, fish, dolphins -

they really don't think much about people

unless you put yourself in the wrong situation at the wrong time

and that's your fault.

In this series, the team got closer to sharks than ever before...

..but they didn't have a single dangerous shark encounter.

There's far more to sharks than just being a predator

and that is what the next programme explores.

The secret life of the shark family

involves social networking,

mysterious gatherings.

We reveal their secret body language,

how the young grow up,

and their complex courtship rituals.