Original subtitles

This is the Okavango Delta

in Southern Africa.

An inland ocean...

..peppered with a thousand islands.

Some are large...

others small.

Here, the sun battles water for control.

Worlds are created...

then taken away.

To survive,

all must cope...

with a state of never-ending change.

From the Arctic... (POLAR BEAR GROWLS)

..to the tropics...

..islands are wild laboratories...

..where unique rules apply...

..and nature puts life...

..to the ultimate test.

In the heart of Southern Africa...

lies the Okavango Delta.

An oasis in the desert.

At its heart are the permanent waters.

These sit along vast, flat plains.

At its farthest reaches are the dry borderlands.

Every year, water surges down the rivers,

fanning out over the desert.

Islands emerge magically from the sand...

..and the largest is Chief's Island.

The delta's waters are constantly changing.

It's now at peak flood...

and Chief's Island is brimming with animals.

(ANIMALS CHITTER)

This is where a hyena clan...

..has chosen to carve out a territory.

(CUB SQUEALS)

They have a queen who rules over the clan.

Under her leadership, they're a stable, social unit

that keeps everyone fed.

They're the largest hyena clan on the island;

over 40 individuals.

They need this large family.

Their island is rich in prey, but also rivals...

(LOW GROWLING)

(CUBS SQUEAL IN DISTANCE)

..all of them vying for control...

..of this prime hunting ground.

Every day, scouting parties strike out

in the search for food.

(HYENAS WHOOPING)

But there's more than just food to be found.

Hyenas welcome the floods.

They love playing in water...

..and these two young sisters...

take full advantage.

(HYENAS CACKLING)

Distracted, they haven't noticed

the rest of the clan has moved on...

(HYENAS WHINING)

..and they are alone.

Without backup...

..they're in danger.

A large pack of wild dogs has spotted them.

(DOG SNORTS)

Wild dogs and hyenas are mortal enemies.

(UNSETTLING MUSIC BUILDS)

So, when dogs outnumber them...

..they'll teach them a lesson.

(HYENA CHITTERS)

(DOG GROWLS)

The sisters can match them for speed

but not stamina...

(DOG GROWLS)

..and they've been separated.

(HYENA SQUEALS)

(DOGS GROWL)

One manages to hold them off...

(HYENA SQUEALING)

..so they turn on her smaller sister.

(GROWLING)

(DOG BARKS)

(HYENA SQUEALS)

It's only the crushing power of her jaws...

..that makes them think twice.

Point made, the dogs lose interest.

Off to harass someone else.

In the future, the sisters must stay closer to the safety of the clan.

(HYENA SQUEALS)

(CUB GROWLING)

Back at their island den,

the rest of the family are enjoying a feast.

(CHOMPING)

But tougher times lie ahead.

Soon, the waters around Chief's Island will fall,

and prey will be free to leave.

Finding food for this large family...

..will become a challenge.

(WIND WHISTLES)

The delta, on which all the animals depend,

is a result of geological events

set in motion millions of years ago.

(THUNDER CRACKS)

Beneath the desert,

Africa started to tear itself apart.

Huge chunks of rock collapsed,

creating a depression. (ROCK CRACKING)

Rivers filled it with sand...

..eventually forming the wide, flat delta we see today.

(WIND WHISTLES)

Every year, these vast plains are covered with flood water...

..revealing thousands of islands.

Some are tiny...

..others larger,

but many have one thing in common.

They owe their existence to some of the tiniest of creatures.

(SINISTER MUSIC)

Termites.

They quietly labour...

..building a city made of soil.

Deep within is something remarkable.

(OMINOUS MUSIC)

The beating heart of the colony.

(TERMITE QUEEN'S BODY SQUELCHES)

This is the termite queen.

She's so large, she's helpless...

..so is cleaned and fed by her devoted workers.

She might be 20 years old.

Her destiny is to reproduce...

..laying 20,000 eggs every day.

Most will become new workers for the colony.

They have a special task.

These tiny insects are island engineers.

(FUTURISTIC ELECTRONIC MUSIC)

They build,

one mouthful of soil at a time...

..glued together with their own saliva.

The termites collect more and more soil...

..a quarter of a tonne a year.

They create a giant mound...

..rising clear of the water.

But this is only the first act.

As weather erodes the soil...

..a platform is created on which more mounds can grow.

Over hundreds of years,

mounds rise, fall,

and rise again.

An island slowly takes shape...

..eventually...

..becoming huge.

These islands, created by some of the smallest creatures...

..are home to some of the largest animals on Earth.

(ELEPHANT GRUNTS)

Over the last few weeks...

..the delta's waters have been falling.

Chief's Island has now disappeared.

And so, times have changed for the hyena clan.

Gone are the days of easy pickings.

Their prized island has withdrawn its greatest benefit.

Before, prey animals were trapped by high water.

But now, they're free to escape the hyenas.

Being the biggest, baddest clan is an asset in the good times...

..but now they're just extra mouths to feed.

Finding enough food is their full-time job.

Hyenas have an acute sense of smell...

(HYENA SNIFFS)

..giving them the edge over other predators.

And there's a scent on the breeze.

(HYENA CACKLES)

A zebra... (HYENAS CHITTERING)

..or what's left of it.

(HYENAS CHITTERING)

Hyenas are the island's recyclers.

Unlike their rivals,

they can digest skin and even solid bone.

(CRUNCHING)

But the clan is being watched...

..by the zebra's rightful owner.

(DEEP GROWLING)

(LION GROWLS)

(HIGH-PITCHED YAPPING)

A male lion can snap a hyena's spine with one bite,

so this is a life-or-death gamble.

(HIGH-PITCHED YAPPING)

(LION GRUNTS)

But the hyenas have numbers on their side.

They can create chaos and confusion.

(LION ROARING)

(HYENA YAPPING)

(LION GROWLING)

(HYENA WHINES)

(LION ROARS)

(DRAMATIC MUSIC)

(MUSIC INTENSIFIES)

(MUSIC FADES)

(GROWLS)

(HYENAS CACKLING)

The lion can't chase them all.

He'll bide his time.

Hyenas better watch out.

(GROWLS)

(HYENAS WHOOPING IN DISTANCE)

For the hyenas, this will keep them going.

Their ability to survive on skin and bones

means there's even enough to take back to the den.

(CUBS SQUEAKING)

The hyenas are getting by...

..but until the delta brings change,

..their future hangs in the balance.

In the farthest reaches of the delta,

the water is now almost gone.

After six months of flood...

..the desert is reclaiming its sands.

These are the borderlands.

Food is scarce.

This barren landscape...

..was once a lush, green place.

(SWELLING ORCHESTRAL MUSIC)

Now there's little more than rutted dirt.

A lone bull hippo is left high and dry...

..using the mud to protect his skin

from the beating sun.

But some...

..have been waiting for this opportunity.

(ETHEREAL MUSIC)

For trapped fish...

..there's no escape.

Pelicans and storks fly in from afar...

..for a final grisly feast.

Soon, even they'll be forced to leave.

Unlike the fish, they have somewhere to go.

(GRUNTING)

Upstream, the hippos are in better shape.

They don't know what's coming.

Their lagoon is already shrinking...

..and it's causing tempers to flare.

(ROARING)

An old male leaves the stresses of the water to feed.

(HIPPO SNORTS)

There's still good grazing to be had around the edges of the lagoon.

But he's not alone;

a young pretender,

eager to find their place in the pecking order.

The old boy's not impressed.

(ROARS)

(TENSE MUSIC)

He gives a final warning...

(GRUNTING)

(BELLOWING)

(GRUNTING)

..but it's foolishly ignored.

(FIERCE ROARING)

(DRAMATIC MUSIC)

(ROARING)

(BIRD SQUAWKS)

Times can be tough living in these ever-shifting waters.

Some face the changes head-on.

Others are forced to leave.

In the north of the delta are its permanent headwaters.

They never dry out.

(WATER BUBBLING)

Millions of fish fry have arrived,

fleeing the receding flood downstream.

The maze of channels seems to offer safety.

What they don't know...

..is others are arriving, too.

A barbel.

A voracious predator,

over a metre long.

And it's not alone.

Following along behind...

..are hundreds more.

They scour the creeks for unwary prey.

The thrashing attracts other predators.

Egrets.

The fish fry are forced to run the gauntlet,

above and below.

(OMINOUS MUSIC)

They're trapped.

Gaping mouths and stabbing beaks are everywhere.

(CHILLING MUSIC)

For the fish that do make it to safety...

..these permanent waters offer a lifeline.

They have survived their trial,

but other animals are about to face their own.

(INSECTS CHIRPING)

On the dry floodplains,

the time has arrived...

..for a magical event.

This is when the termites breed.

A chance to start a colony,

and the first steps in creating a new island.

The next generation of winged lovers takes to the air,

looking for a mate.

But it's a hostile world outside their mound.

As soon as they touch down, they shed their wings.

They must move quickly.

Exposed on the surface,

they're in danger.

The males begin a frantic search for pheromone trails...

..chemical messages leading to the females.

The odds, however, are stacked against them.

This bumbling protein buffet is bound to attract attention.

Marabou storks.

The termites are a welcome, if unexpected...

breakfast.

(QUIRKY MUSIC)

Sand toads wake from hibernation to join in.

Even ants take care of the stragglers.

He's avoided being eaten and found what he hopes will be...

..his new queen.

Now, he must keep up...

..moving as quickly as they can to find what they're looking for...

..soft ground.

Then, without delay,

they dig their marital burrow...

..which, in the coming years...

could become part...

..of a new Okavango island.

After months of drying out,

the delta is shifting.

Change is on the way.

New floodwater is finally flowing through its veins once more.

First a trickle.

Then...

a flood.

The water will reclaim over 8,000 square kilometres of desert

and restore thousands of islands.

(TRIUMPHANT MUSIC BUILDS)

With it come animals...

(LOW GROWLING)

(ELEPHANTS SNORTING)

.in their thousands...

(BIRDS CHIRPING AND HONKING)

..making the most of fresh grass.

(UPLIFTING MUSIC)

On Chief's Island, the flood is back once more.

The rising water has rebuilt the island.

The hyenas' prime territory is restored.

There's also been a baby boom.

This couldn't happen in the borderlands or beyond.

Hungry youngsters are everywhere.

And there are more to come.

The clan queen...

..is also expecting.

With so many extra mouths to feed...

..scavenging is now a full-time job.

Being pregnant doesn't mean she's excused duties.

So, she sets out,

playing her part in the search for food.

(SNIFFING)

She's picked up an unmistakable scent.

(SNIFFING)

(FLIES BUZZING)

Disease has taken its toll on elephants,

weakened by the long dry season.

(FLIES BUZZING)

It's also attracted...

unwelcome visitors. (BIRD SQUAWKS)

(SQUAWKING)

Vultures...

(HYENA GROWLS) (VULTURE SQUAWKS)

..a signal to every predator around

that there's a feast to be had.

An old foe returns.

(LOW GROWLING)

(VULTURES SQUAWK)

(LOW RUMBLING GROWL)

(OMINOUS MUSIC)

If he catches her, he could easily kill her.

(LION GROWLS)

(VULTURE SQUAWKS)

But she isn't giving up.

Her unborn cubs need her to succeed.

(LION ROARS)

But she doesn't have numbers on her side...

..yet.

She calls for backup. (HYENA WHOOPS)

(HYENA WHOOPS)

(HYENA WHOOPING)

Her whoop is a call to arms.

(HYENA WHOOPS)

(HYENA WHOOPING)

Clan Hyena mobilises.

(DRAMATIC MUSIC)

The tables have turned.

(HYENA WHOOPING IN DISTANCE)

Now it's the lion who's in trouble.

(BIRDS CHIRPING)

(HYENA SHRIEKS)

(LION ROARS)

This could have been a bloodbath...

..but the delta has delivered for both.

There's more than either could possibly eat.

(HYENAS YIPPING)

In a moment rarely witnessed,

they settle for an uneasy truce.

(HYENAS SLURPING)

The queen of Chief's Island can feed in safety for now.

And inside her,

the next in line to the island throne will grow strong.

In the floodplains, returning water is consuming the land.

Some animals welcome it...

..but it's not good news for everyone.

It's forcing baboons to find a new home.

The delta's largest primate,

they must find an island that can support the family of 15.

If there's one thing the delta isn't short of now...

..it's islands.

And this one has its own fruit tree.

This is just what they're after.

Figs.

the delta's superfood.

But youngsters are more interested in their new playground.

(BABY BABOONS CHATTERING)

The baboons can relax...

..but below...

..the termites are on full alert.

(QUEEN TERMITE'S BODY SQUELCHES)

The returning waters threaten to drown their colony.

They must waterproof their tunnels

before it arrives.

It's a race against time.

But they have another problem...

..one that comes from within and threatens

to undo all their hard work.

The termites have entered into a partnership with a white fungus.

They tend and feed it.

In exchange...

..it provides almost their sole supply of food.

The termites may be doing everything to stop water coming in...

..but their fungus is trying to break out,

growing through the tunnels...

..throwing out mushrooms...

..so it can release its spores.

But mushrooms are irresistible to baboons.

And to get them, they break open the mound.

The termites swing into action,

sealing the breach from the inside.

(FRENZIED MUSIC)

It will dry hard as rock...

..keeping out the neighbours and the coming flood.

(WIND WHISTLES)

Some islands are forged by the earth...

..others by tiny creatures,

but in the headwaters,

it's giant animals that change entire landscapes.

The water here is deep and permanent.

It's so wet that some of the islands literally float.

And abundant plant life provides year-round food for elephants.

(ELEPHANT SNORTS)

This is why they choose to stay in the delta.

The good times outweigh the bad.

And these massive animals

are capable of causing huge changes to the delta.

(UPBEAT PERCUSSIVE MUSIC)

Elephants dislodge vegetation...

..which accumulates into rafts...

..growing as they journey.

They can come together...

..to create floating islands.

Hippos then take over.

They crash through vegetation...

..creating channels...

a spiderweb of waterways...

..others can exploit.

The hippos also keep the lagoons open...

..which allows more delicate plants, like waterlilies, to grow.

They may only be small,

but these lily pad islands have a big influence.

The leaves give shade,

helping to keep the water cool and give cover to fish.

And their flowers offer rich nectar.

The lily pads are home to a bird that spends its days island hopping.

The jacana, or lily-trotter.

Exceptionally long toes spread its weight.

It can almost walk on water.

The jacana has evolved to spend its entire life...

..on these floating islands.

The lilies provide food...

and a place to raise a family.

(CHICK CHEEPING)

(INSECTS BUZZING)

(CHEEPING)

Chicks are brought up by their single dad.

He has a clever way of keeping them safe.

(CHICKS CHEEPING)

(HIPPO SNORTS)

He carries them under his wings...

..until they find their feet.

(HIPPO GRUNTING)

But this family is being watched.

(CHICK CHEEPS)

The hippo is not the problem.

(HIPPO GRUNTS)

A rival jacana is eyeing the territory.

But Dad's not going to let anyone muscle in on his lilies.

(SQUAWKING)

(FRENZIED SQUAWKING)

Calm restored...

..for now at least.

Chief's Island has come through for the hyena clan.

Their scavenging adaptations saw them through the tough times.

So now...

(HYENAS YAPPING)

..they can enjoy the good times.

(CUBS YIPPING)

And their island queen...

..also has a new arrival.

The latest member of the Chief's Island clan.

(CUB SQUEAKS SOFTLY)

The delta shapes the lives of every animal

that lives within its powerful influence.

They respond to its dynamic ebb and flow of water.

For some...

this brings challenge.

But for others...

..the delta brings great benefits...

..that enable them to prosper.

As long as the distant rains continue to fall,

this unique world of island...

..will emerge every year...

..from the desert sands.

(EPIC ORCHESTRAL MUSIC)

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