Massive Nature

The southern tip of the African continent.

Sailors once called this "The Cape of Storms"

These waters seem forbidding and without life.

But just below the surface,

one of the world's greatest wildlife spectacles

is about to emerge.

Rising up from the depths,

appears to be one giant creature.

But appearances can be deceptive.

This is one single animal,

but millions. It's a massive shoal of sardines

100,000,000 little fish are about to begin 1000 mile journey

up the African coast.

And on course to intercept them are armies of deadly predators.

Tens of thousands of them.

If they will find the sardines

one of nature's greatest confrontations will take place.

This is Massive Nature.

But why here ?

And why now ?

In an attack of this scale,

the life of every single little fish will be on the line.

So, at the moment of impact, is it all over for these sardines ?

Or did some still have a change to save themselves ?

And are these sardines the only ones in danger ?

Because even hungry predators have predators of their own.

Dolphins and sharks are deadly enemies.

Will they turn on each other ?

It's a moment when life hangs in the balance for both predator

and prey.

The future of all these animals would depend on a chain of events

that begun 6 months ago,

more than 1000 miles down the coast.

Our story starts in deep water,

off the southern tip of Africa, on the Agulhas bank

a safe place for sardines.

It's their nursery.

Here hundreds of millions of tiny fish are growing,

breeding and multiplying.

They're safe here, for now.

But they can't stay here forever.

Before long , something will set them on a journey up the coast of Africa.

And that something is food.

In winter a cold current sweeps 1000 miles up the coast

carrying with it the sardines plankton food.

When the time comes, the sardines will have no choice, but to follow.

Their dangerous journey will take them past Bird Island

It's the world's largest colony of fish-eating gannets.

Here, 100000 birds are gathering to breed.

Timing is critical.

Although they'll have almost 6 months to raise their chicks before the sardine shoal passes by,

not all will be ready.

And while the gannets await the sardine's arrival

on a nearby island, 7000 cape-fur seals are gathering to breed.

With such massive numbers in this colony

the seals can't simply wait for the sardines to arrive

they'll need to start hunting closer to home.

And that could put the gannet chicks in real danger.

The first great storms of winter trigger a big change in the ocean currents.

The life-sustaining plankton is swept out of the sardine's nursery.

And with billions of new mouths to feed, the massive shoal sets off on its epic journey.

Sheer numbers force the sardine shoal to follow their food,

even if it means leaving the safety of these deep waters.

As the shoal begins its incredible journey

hundreds of miles up the coast, yet another animal is preparing to join the hunt.

Common dolphins thrive in the seas along the coast of Africa

They're social, playful animals,

but also intelligent and cunning hunters.

These dolphins will, in fact, be the brains behind this whole sardine hunt.

Because if they don't find the fish, then none of the other predators will, either.

Somehow, they sense the sardines are on the move

and they mobilize their own massive force.

They bound together into a huge armada

5000 strong, a dolphin super pod,

assembled with the soul purpose of hunting down sardines.

But in these numbers, they can also become a target.

For in these same coastal waters are sharks.

They're normally solitary hunters, except when there's a dolphin super pod on the move.

Now they too gather in their thousands, and begin their search for the dolphins.

But will these sharks find the dolphins, before the dolphins find the sardines ?

Halfway through their journey, and still safe in deep water,

the shoal moves on relentlessly.

Each little fish is blissfully unaware of the gathering of predators

Amassing in their honor.

On Bird Island, the gannet chicks have hatched.

These young birds must fatten up fast,

and learn to fly soon, if they are going to join the sardine hunt.

They'll need these fat reserves to tide them over

until they can learn to fly with the rest of the colony,

and that will make them a target.

Nearby, at the seal colony,

a new generation of predators is about to take to the water.

And all these pups will soon be learning their own survival skills.

As the numbers swell, the pressure mounts on the seals, too.

And, like the gannets, they will be forced to leave these islands, in search of food.

When that time comes, these young pups will have to fend for themselves,

in ever more dangerous waters.

The odds seem to be stacking up against the sardines

but for now they're safe, so long as they remain in deep water.

And even if they were to be found here, being part of the massive shoal

means the odds of survival are good.

But shoaling comes at a cost.

Hiding in the middle, a fish may be safe, but there's precious little food here.

So each fish must take its turn at the edge of the shoal, where it can feed,

but where it also risks becoming food.

Being part of the massive shoal, also makes them easier to find.

And there's one predator with a plan to do just that.

A few hundred miles off the coast, the dolphin super pod is now on the move.

With so many mouths to feed, their search is becoming desperate.

They're now using a combination of intelligence and sonar

to try and locate the sardine shoal.

Highly organized, they set up a sweeping front

a line of scouts, several miles wide, to scan the sea for signs of the sardines.

But as a dolphin's sonar beams out