Original subtitles

This is the inside story of four extraordinary predators.

The peregrine falcon...

the Nile crocodile...

the cheetah...

and the great white shark.

With ground-breaking computer graphics...

and incredible close-up photography...

we reveal the inner alchemy that gives our hunters the edge.

Reconstructing their intimate lives as they make their kills.

But who is the planet's perfect predator?

Living right above the heads of the people of London...

..the fastest animal on the planet,

the peregrine falcon.

Man-made cliff tops offer sanctuary to the peregrines...

..but they also present new dangers.

With the arrival of spring come new demands

on the peregrines' hunting skills.

Demands that will stretch them to their limit.

There are new mouths to feed.

If these chicks are to survive long enough to fly the nest,

their parents will have to catch two pigeons a day for the next month.

This will be the greatest challenge of their mother's life.

Her secret weapon is speed.

But on the flat, a pigeon can out-fly a peregrine.

She must use gravity to reach her maximum speed.

For this, she rides the updraft.

Half a mile above the city,

she can now survey the whole of her territory.

Of all the four predators,

the peregrine falcon has the keenest eyesight.

At the base of each retina,

she has two concentrations of visual sensors,

where humans have only one.

This gives her incredible powers of triangulation.

From two miles away, she locks on to her unsuspecting target.

The hunt is on.

While this peregrine falcon must kill every day,

there's one predator that can survive without food for a year.

It lives in the rivers of Africa.

Even when they have run dry.

Months ago a five-metre, half-ton Nile crocodile

scraped out a burrow to escape the heat.

Now he's in a state of suspended animation.

His heart beats only twice a minute...

..delivering just enough blood

to keep his vital organs from shutting down completely.

To survive, he draws on the fat reserves

accumulated from last year's hunt.

In this condition, he rides out the worst of the drought.

THUNDER RUMBLES

When the rains finally return...

..the predator

flickers to life.

But before the cold-bloodied reptile can hunt, it must first power up.

The ridges of scales along his back are more than just body armour.

They act like solar panels, absorbing the heat.

Just beneath the surface, a web of capillaries carries the warm blood

to the crocodile's core...

..activating his systems.

His eyesight sharpens.

His hearing tunes in to the world around him.

BIRDS SCREECH

For the next six months, he must make do with only fish to snack on.

Then, it is the moment he's been waiting for.

Inside his ears,

minute hair-like structures detect a low-frequency sound

well beyond human hearing.

It's the rumble of a distant stampede.

for fresh pastures.

Finally, he has his quarry in his sight.

The hunt is on.

While the crocodile can wait for prey to come to him,

another predator must make an epic journey to reach hers.

Deep in the Indian Ocean,

the world's largest predatory fish is heading to her feeding grounds.

One ton and five metres long, this female great white shark

left the coast of Australia over 100 days ago on a 7,000-mile journey.

She cruises half a mile down, in a world of pitch black.

Up above,

fishing fleets are scooping out the last of the big shoals.

Down below, the shark is burning the last of her fuel supply.

She has almost exhausted the fatty oils in her liver.

She must get to her feeding grounds soon.

Highly sophisticated electro-sensors in her nose...

..allow her to detect the Earth's magnetic grid...

..and accurately compute her position.

Occasionally, she returns to the surface,

possibly to get her bearings from the stars.

Finally, the near-starving shark reaches her destination,

the coast of South Africa.

It's early winter and she has timed her arrival to perfection.

Thousands of six-month-old Cape fur seals are venturing

into deep water for the first time.

Thanks to their energy-rich blubber,

these seals would make a perfect meal for most sharks.

But most sharks can't cope with these cold temperatures.

They're cold-blooded

and lose body heat as their blood passes through their gills.

The great white, however,

uses a specialised network of blood vessels to reabsorb its body heat.

Because of this, it can raise its body temperature

14 degrees higher than other sharks,

giving it superior strength, speed and brain power.

She's crossed an ocean to be here.

It's time to eat.

From two miles away, she can smell the colony,

able to detect one molecule of blood in a million of water.

From 250 metres away,

she can distinguish the sound of seals from the background surf.

From 25 metres, she can make out surface objects

only 15 centimetres across.

The hunt is on!

While the ultimate sea predator can go without a kill for weeks,

the ultimate land predator must kill almost every day to survive.

The fastest animal on land

has had the run of the African plains for millennia.

But sometimes speed isn't enough.

The cheetah.

So far, this mother has succeeded in keeping her three cubs alive...

..when typically, only one would reach its first birthday.

Hyenas.

They will kill cheetah cubs.

Not only do they have strength in numbers, they're also bigger,

with bone-crushing jaws.

To protect her young, the cheetah must act as a decoy.

Inside, her body fires into action.

Adrenalin is quickly flushed into the bloodstream.

Her huge heart doubles its rate to 250 beats a minute...

..sending extra oxygen and sugars directly

to her enormous leg muscles.

She is now ready to engage the enemy.

This time, she has won.

But her cubs are hungry.

They need meat and milk every day.

She too is weakening.

To achieve her killer speed, she carries little fat

and is constantly on the verge of starvation.

She must eat.

Cheetahs have enhanced vision in the horizontal plane...

and can spot a moving gazelle from over a mile away.

Approaching downwind, she creeps towards

her 30-metre striking distance...

..making the most of her camouflage.

Once again, there's a chain reaction...

as she prepares for the fastest chase on land.

The hunt is on.

All four predators are poised for the attack.

Their insides a powder keg...

just waiting to explode.

But who will make the kill, and who will go hungry?

Nature's top gun, the peregrine falcon.

Desperate to feed her chicks...

..she locks onto her target, a fast and agile pigeon.

Time to turn on the speed.

Tucking in her wings, she shoots towards Earth.

Her teardrop-shaped body, the height of aerodynamic design.

Within seconds, she has reached

her terminal velocity of 200 miles per hour.

The force of air would explode her lungs,

if not for the baffles in her nostrils,

a design so effective it is now used in jet engines.

Nictating membranes wipe her eyes

to clear them of debris and stop them drying out.

She prepares for impact, a manoeuvre requiring split-second timing.

But the pigeon spotted her...

and she can't compete on the flat.

Despite their speed, peregrine falcons have a poor strike rate,

with only 20% of attacks ending in a kill.

But her chicks must feed before the day is out.

Back in Africa, hunger is also preying on the mind

of the freshwater predator.

So far, this Nile crocodile has survived on meagre pickings.

Now is his chance for a proper meal.

The crocodile is an ambush predator.

But to succeed, he must get close.

No more than three metres away.

The wildebeest are wary of any movement.

For his final approach, he must vanish completely.

Although he can barely see, he uses his claws to feel his way forward.

Pressure receptors studded along his jaws pick up vibrations

in the water...

..guiding him to his prey.

A large crocodile can hide itself in 30 centimetres of water.

Now, he must wait for them to come to him.

By lowering his heart rate...

..and slowing down his metabolism...

..he can stay submerged for up to two hours.

Finally, the temptation to drink is too much for the wildebeest.

He swipes his muscular tail, half his body length.

It launches him three metres out of the water.

He shuts his eyes to protect them...

..and snaps blindly, his jaws studded with five-centimetre fangs.

He's missed.

The Nile crocodile's hit rate of 30%

may beat that of the peregrine falcon...

..but the wildebeest are only fleeting visitors to his river.

He must make a kill soon if he is to survive the lean times ahead.

Drained after an epic voyage,

the ultimate ocean predator is also ravenous.

She's come all this way to feast on the thousands of young seals

braving open water for the first time.

25 metres down, she launches her lightning strike.

Three-quarters of her bodyweight

is muscle that powers her enormous tail.

Thanks to her fortified scales, her streamlined body

glides through the water with minimal friction.

At 31 miles an hour, she's like a living torpedo.

Moments before the strike, she rolls her eyes back to protect them.

Steering blind, she now depends on her sixth sense.

The electro-sensors on her snout detect the seal's electric field.

Her jaws open almost a metre wide...

..revealing row upon row of serrated daggers.

With a 50% hit rate, she is the most efficient hunter so far.

But she must consume more blubber

if she's to make it back to peak condition.

Back on the African plains,

the fastest land animal is moving in for the kill.

The survival of her cubs is at stake.

From 0 to 60 in under three seconds, she outperforms a Porsche.

Extra-wide airways and outsized lungs

allow her to take in more oxygen.

Loose hip and shoulder joints give her extended reach.

Combined with an elastic spine...

..that both arches up and curves down.

This gives her a seven-metre stride.

For more than half the time, she is airborne.

Thrusting her forward are her huge leg muscles...

..composed mainly of fast-twitch fibres

that contract far quicker than normal muscles...

..and that run on glycogen, nature's own rocket fuel.

But there's a catch.

Glycogen breaks down into lactic acid,

the poison that causes muscle cramp.

She has just 20 seconds to make her kill before her muscles burn out.

Hurtling at 70 miles an hour, she risks everything on a trip.

With a 50% strike rate,

the cheetah matches the efficiency of the great white,

but holding onto her kill will be another matter.

By strike rate alone, the cheetah...

..and great white are the top predators.

Snapping at their heels is the Nile crocodile...

with the peregrine falcon swooping into fourth.

But there is more to survival than just hunting.

The great white has made her first kill

but she must make up for lost time.

Kill number two.

Her liver starts to store its fatty oils, but she still needs more.

Over the short winter season,

an experienced shark may catch up to three seals a day.

Months later, however, the tide has turned.

The seals are both stronger and cannier.

While some are still being eaten...

..most can now run rings around their enemy.

The shark's incredible metabolism is both a strength and a weakness.

Like the cheetah, her fast-twitch muscles

are perfect for short bursts of speed but quickly burn out.

The exhausted shark gives up.

But she's done well.

Her fatty liver has now doubled in size.

With energy in reserve, she moves on to her next feeding ground...

..one that may be hundreds of miles away.

But avoiding the fishing fleets is becoming more difficult.

Her luck has run out.

This ruthlessly efficient predator

has ruled the waves for millions of years,

but now these waves are ruled by humans.

So what does the future hold for the other top predators?

On the African plains, the cheetah has made her kill.

But the chase has attracted attention...

..and taken its toll on her body.

Struggling to recover, her lungs heave at 200 breaths per minute.

Oxygen races to her aching muscles...

..breaking down the cramping lactic acid.

But time is running out.

This time, the hyenas went for the easy meat.

But it was meat that the cubs desperately needed.

In the past, cheetahs could avoid their enemies.

But now, their grasslands are shrinking

and being replaced by farmland...

..where the cheetahs are considered a threat to livestock...

..and shot.

She may have had the run of the plains for millennia,

but in the next 30 years the cheetah may become extinct in the wild.

Rapid change is sweeping across the African landscape.

The crocodile's first ambush was a spectacular failure.

To survive the dry season, he must catch a wildebeest

in the few weeks they are passing through.

This time, his jaws find their mark...

..bringing two tons of pressure to bear on each square inch of flesh.

At last, he has his prize.

Rather than fend off the other crocodiles,

he welcomes them to the feast, unable to dine alone.

His teeth may be formidable but they are grippers, not carvers.

Together they perform twisting death rolls

to rip the flesh into bite-size chunks.

A croc's stomach can hold over 25 kilos of meat.

To help him digest the cache before it begins to rot,

the crocodile has a unique adaptation.

His heart.

No other animal has two aortas.

By closing his right aorta, the main blood supply to his body,

and opening up his left aorta,

he can divert the carbon dioxide-rich blood

that he accumulated during his underwater stake-out

straight to his stomach.

The acidic blood produces ten times more stomach acid...

..to help dissolve the huge chunks of meat.

The potent solution is then converted to fat

and stored for the lean times ahead.

He's made his big kill just in time.

His world is slowly turning to dust.

The wildebeest are moving on.

It's time to escape the furnace.

He shuts down once more.

He has only his new fat reserves to see him through to the next rains.

Thanks to the crocodile's remarkable physiology,

it has outlived the dinosaurs and survived the ice ages.

Now, there is every chance it will weather the worsening droughts

brought on by climate change, too.

All the predators have challenges ahead.

But some may fare better than others.

Like the crocodile, the peregrine's first strike was a miss.

As her chicks depend on a daily kill...

..the stakes could not be higher.

Moments before impact...

..she unleashes her five-centimetre talons.

The force of the blow snaps the pigeon's backbone.

CHICKS CRY

Today, the hungry chicks get to eat.

But their parents will have to do this

every day, twice a day, for a month, if all three chicks are to survive.

Weeks later, these three rookie predators

are testament to their parents' perseverance.

Despite their challenges, and their low strike rate,

urban peregrines are on the rise.

Around 30 of the world's fastest animal now soar over London.

All four predators have incredible inside stories.

But the real perfect predator

is the one that can best adapt to a rapidly changing world...

..and learn to live alongside humankind.