All language subtitles for BBC.Earths.Greatest.Spectacles.03.of.03.Okavango.1080p.HDTV_english

Our planet is a place
of constant change.

Each year, the seasons shift
and life is transformed.

But there are places where
the changes are so epic in scale,

they can be seen from space.

In this series, we reveal three of
the most miraculous transformations.

The islands of Svalbard.

Within a few weeks,
frozen wastelands burst into life.

The African Okavango.

A desert transforms into
a magical water world.

And the mysterious forests
of New England

erupting in a blaze of
seasonal colour.

Life finds the most ingenious
and surprising ways to thrive...

..in the world's most
fast-changing landscapes.

The Kalahari basin.

2.5 million square kilometres
of flat sand and scrub.

This desert stretches across
southern Africa.

But at its heart lies a river.

A river that never reaches the sea.

And once a year, it floods.

Over five months, waters spread
across a vast area of the Kalahari,

transforming it into a wonderland.

The Okavango Delta.

This is the story
of how nature creates a unique,

flourishing wetland
out of one of earth's great deserts.

Our story begins
in the heart of the Delta.

The dry season is well advanced

and water is becoming scarcer
by the day.

At this time of year,
predators rule.

Animals have another
six months to wait

before the flood turns this land
back into a lush wetland.

Sable antelope.

After grazing on dry grass, they
have to drink at a stagnant pool.

But they're nervous.

Predators watch their every move.

For a leopard, though,
a sable's size

and lethal scimitar horns
pose too much of a risk.

There are plenty of easier targets.

A family of warthogs.

GRUNTING

Where once there was a wide river,

they use their tough snouts
to truffle for bulbs.

But it's hard work
in this dry, sun-baked ground.

And having your snout in the sand
is decidedly risky.

GRUNTING

SQUEAL!

FRANTIC SQUEALING

SQUEALING

The leopard drags its kill
to a hiding place,

where it can dine in peace.

The warthog will keep it going
for a week.

The dry season means good hunting
for top predators.

For everyone else, food is scarce.

Chacma baboons survive
through their knowledge...

..and eclectic taste.

BUZZING

Elephant dung is a valuable source
of seeds and insects.

CHATTERING

But it looks like
there's an appealing alternative.

A tree that fruits
even in the dry season.

A fan palm.

The fruit is nutritious,
if a bit tough and pithy.

But what's this?

Elephants will eat
virtually any vegetation.

And fruit is their favourite.

They can smell it from
several kilometres away.

For the baboons, the feast is over.

TRUMPETING

The fruit may be 20 metres up
and out of reach,

but the elephant's strategy
is simple.

Brute force.

For a crafty baboon, though,
it sometimes pays to hang around.

It's spotted one
that the elephants missed.

Nearby, at a shrinking pool,
something agitates the water.

Mouths gulp at the surface.

It's crowded with giant catfish
up to a metre-and-a-half long.

There's no oxygen left in the water
for their gills to use.

But these fish also have
lung-like organs that breathe air.

Every day, under the Kalahari sun,
more water evaporates.

African fish eagles
gather expectantly for a banquet.

In desperation, some catfish
attempt to make a run for it,

using their fins to propel them.

Now exposed, they are easy targets
for eagles and jackals.

SQUAWKI NG

These catfish have run out of time.

Within two weeks,
the pool has vanished.

When it floods, there will be
plenty of water for everyone.

But now,
at the end of the dry season,

elephants must keep walking
in search of water.

LOW ROAR

Her calf needs
15 litres of milk a day,

so she must find over 100 litres
of water for both of them.

But elephants have a special
technique to get at fresh water.

No other animal has such power.

Using their tusks,
they pile-drive into the flood plain

until they reach water
beneath the surface.

TRUMPETING

In doing so, elephants create
a lifeline for others.

A hyena and jackal wait their turn.

Elephants with calves
are not to be messed with.

So they dive in when they can.

But this jackal may have pushed
its luck a little too far.

CHATTERI NG

BI RDSONG

For insect-eating birds,
food is increasingly hard to find.

This mound makes
a good lookout post.

But if only it knew what's inside.

It's a fortress
for Macrotermes termites.

A colony a million strong.

A termite's mound is just the hub
of an underground city.

Six kilometres of foraging tunnels.

Here, the Macrotermes process
dead vegetation into food.

The mound is perfectly engineered

to keep air at constant temperature
and humidity.

Protecting the termites
from drying out.

But these mounds will also
prove essential

for the survival of many other
species when the floods come.

By the end of October,
dryness and increasing temperatures

turn the once-lush Okavango Delta
into a tinderbox.

FLAMES ROAR

But these birds seem to be
attracted to the flames.

For the lilac-breasted roller
and the fork-tailed drongo,

it's a great opportunity.

Because the fire flushes out
a bounty of insects.

Up to a quarter
of the Okavango flood plain

can burn in a single year.

For most of the plants and animals
that live here,

the end of the dry season
can't come soon enough.

THUNDERCLAP

RAIN PELTS

November brings a little respite
to the parched land.

THUNDERCLAP

Warm, humid air moves in
from the tropics.

Rain in the Kalahari.

Just enough to green the delta.

BIRDSONG

CHATTERING

The baboon troop
has grown in number.

SQUEALING

These youngsters were born just in
time to enjoy what the rains bring.

More trees have come into fruit.

It makes for a delicious breakfast.

But there's a downside
to such a wonderful scent.

TRUMPETING

Sure enough,
elephants aren't far away.

TRUMPETING

GENTLE ROARING

The troop scatters.

SQUEALING

Maybe it's time to move on.

Mothers carry their newborns
safely underneath,

where they can keep suckling.

But the older ones
must learn to ride on top.

CHATTERI NG

On these open plains,
the troop must stick together.

Some have already lost limbs
to leopards.

All these animals
will soon face a new world.

The Kalahari rains may have provided
some temporary relief,

but a much greater change
is on its way.

In distant mountains
beyond the Kalahari,

the tropical air now brings
much heavier downpours.

Rain, from highlands to the north,

cascades ultimately into one river.

The Okavango River.

It creates a pulse of high water

which takes two months to snake over
a thousand kilometres

to the top of the Okavango delta.

It will still be another month

before the floodwaters reach
the heart of the delta.

Here, the river always flows

and is home to several
thousand people, such as Sinabe.

His people are descendants
of both Kalahari nomads

and fishermen from central Africa.

As the river rises, water spills
on to the surrounding land.

Creating shallows
ideal for spear-fishing.

The rising pulse of water
continues onwards.

South,
towards the dry heart of the delta.

But to understand what happens next,
we have to go back in time.

Two million years ago, great cracks
ripped through the desert floor.

The land warped to create the shape
of the Delta we know today.

The faults define the start
and finish lines for the flood

which is to come to the main delta.

The dry plains in the heart of
the Delta will soon be transformed.

GRUNTING

Life here is about to be turned
upside down.

GRUNTING

SQUEALING

But for this family of warthogs,

there's still a bit of time
to get some truffling in.

The last rains softened the ground.

And now, getting at those tubers
is much easier.

For the cunning baboons,
it's an unmissable opportunity.

They muscle in to enjoy the fruits
of the warthogs' hard work.

GRUNTING

SQUAWKING

The baboons may have no manners,

but the warthogs
don't really seem to mind.

Perhaps it's because the baboons
provide extra security.

But this is one food source
that will soon disappear.

Hidden in the reeds,
it starts as the tiniest trickle.

The beginning of one of Africa's
greatest floods.

As rising water spills into
the main delta,

it slows and spreads
into countless, tiny rivulets.

RHYTHMIC DRUMBEAT

Travelling at barely
a kilometre a day,

the flood will take another
four months to cover the delta.

But straightaway,
wherever water touches the land,

it makes a remarkable impact.

Common sand frogs
spend most of the year

buried half a metre underground.

But now, water floods their burrows
and forces them to the surface.

They inflate to scare off
any predators.

He's off to find a female.

For tiny creatures
whose homes are in the way,

the trickle is more like a tsunami.

Ants are forced to evacuate
their nest.

An easy snack
for blacksmith lapwings.

Termites now face the flooding
of their colony.

They beat a hasty retreat
to the safety of their mound

as their tunnels start to flood
and collapse.

But in doing so,
something miraculous happens.

The tunnels seal themselves up.

This blocks
the flood's underground advance

and forces the water
back to the surface.

Back inside the mound,
the termites are safe.

Incredibly, the flood provides
just the opportunity they need.

Their fragile castle, made of sand,

requires constant maintenance
and rebuilding.

But the soil,
now softened by floodwater,

is easy to transport
to damaged parts of the mound.

Gradually, thousands of termites
reconstruct their fortress.

Repairing these mounds
isn't just good for the termites.

These structures help to create
something vital

for all the delta's wildlife.

Its islands.

And it all starts like this.

Dung.

Readymade fertiliser
laden with fruits and seeds.

Floodwater soaks up
the dry side slopes of the mound

to create the perfect
bedding for new plants.

Gradually, season-by-season,

termite mounds become home
to more and more plants.

As they grow,
they attract more animals,

which in turn bring with them
the seeds to grow even more plants.

Sycamore fig, fan palm, marula.

Until the termite mounds
are barely recognisable

under their lush green canopies.

As it floods, raised areas around
termite mounds become islands.

They provide food, shelter
and a refuge throughout the year

for everything from elephants
to baboons and birds.

In the delta,
once featureless desert,

there are now around
150,000 such islands.

For a lot of thirsty animals,

the floods simply mean
sweet drinking water.

Elephants no longer need
to dig holes.

TRUMPETING

CHATTERING

GRUNTING

Baboons, too, seem to delight
in the precious liquid.

Curious youngsters, encountering
the flood for the very first time,

don't seem to know
quite what to make of it.

The sand may look barren,

but wherever the water touches it,
something magical happens.

Within a couple of days,
billions of freshwater plankton

begin to awake and hatch.

Such tiny creatures
are the delta's secret ingredients.

The foundation of its food chain.

Meanwhile, in a deeper channel,

a mountain of foam has appeared.

It has been created
by a pair of African pike.

Notoriously aggressive,

but caring parents
that watch over their offspring.

Hidden safely underneath the foam,

hundreds of fish eggs
are beginning to hatch.

The fry remain attached to the foam
until they are well developed.

And now, the delta offers plenty
for them to eat.

The tiny pike fry join small,
hungry fish of 70 different species,

swimming though the shallows

in a nutritious soup
of freshwater plankton.

BIRDSONG

Before long,
the skies fill with birds.

One of Africa's greatest
wildlife spectacles.

Travelling nomads from far and wide.

The reason they're here?

Wherever water covers the land,
it fills up with little fish.

Each of the birds has its own
special technique for catching them.

A saddle-billed stork
jabs at its prey.

African spoonbills
have the perfect equipment

for filtering out
the finest morsels.

Black egrets use their wings
to form canopies over the water.

The shade lures nervous fish
desperate for cover.

Others attack directly from above.

A pied kingfisher.

At 25 centimetres long,

it's the world's
largest hovering bird.

Hovering demands a lot of energy,

so they have to catch a quarter
of their weight in fish every day.

Keeping its head perfectly still,

about ten metres above the water,
it sees movement.

Then drops in a controlled dive.

If the fish sees it, the kingfisher
can still abort and save energy.

If not, it commits
and dives rapidly.

It's worth the effort.

Hovering allows them to hunt
in the middle of the plains,

where the pickings
are especially rich.

The bird kills its prey
with a blow to the head.

But before it can swallow,
it must flip the fish, head first,

or the spines will stick
in its throat.

Within a few months,
another type of organism

vital to the delta
breaks the surface.

Dozens of species
of aquatic grasses,

sedges and water lilies.

At dawn, day lilies open

to attract pollinating bees
and flies.

As dusk approaches,
the day lilies begin to close,

and give way to the night shift.

Night lilies open
their brilliant petals...

..bright enough to attract insects
in the moonlight.

Water lilies, flourishing in the
middle of the Kalahari desert.

Perhaps the greatest
miracle of the delta.

And only possible
thanks to one thing.

Nature has found a unique way
to keep the water of the Delta

pure, very low in toxic salts.

Its secret lies with those
extraordinary islands.

Trees on the islands act as pumps,

sucking in water
from the surrounding swamp.

As they do so,

salts in the water are deposited
in the sand of the islands.

By extracting salt from the water,

it's as though the islands
are kidneys,

removing waste from the bloodstream.

This way, the islands keep
the Delta's waters fresh

and able to nurture abundant life.

As the morning sun heats the ground,
rising vapours everywhere

reveal that water has spread
right across this plain.

It's a transformation that turns the
tables between predator and prey.

Red lechwe appear in large numbers,
looking for their favourite food...

..tender aquatic plants.

But a hyena hopes to take
advantage of their distraction.

It just needs to get
a little closer.

Time to run for it.

Lechwe have large splayed hooves

that allow them to bound at speed
through shallow water,

giving them
a big advantage over any predator.

It's an adaptation that helps
to protect them

during the time of flood.

Soon the aquatic vegetation
sprouts everywhere

and the water becomes impassable.

But crisscrossing
the flooded plains,

highways through the reeds appear.

And here's their creator -
a hippopotamus.

He's a grazer and thinks nothing
of bulldozing a way through.

As he does so,
he excavates a channel.

And it's not only hippos that
have to find a way through.

In the far north of the Delta,

Sinabe rows through dense
beds of reeds.

To get through, he seeks
the help of the spirit of the river.

Deep in the reeds,
he discovers a hippo channel.

It's a highway for fish,
so the perfect place to rig a net.

Sinabe's village is
on the edge of the flood plain.

His family know that
as long as the Delta provides,

they will never go short of food.

He smokes the bream
to preserve it

for days when the catch
isn't quite as good.

Meanwhile, his family weave baskets
out of grass from the flood plains.

Later in the year,
they will be used for catching fish.

By July, in the heart of the Delta,

the once-dry savanna has become
a lush water-world.

But this transformation has
an odd effect on the baboons.

SQUEALING

Each has developed
its own funny walk.

SCREECHING AND GRUNTING

SCREECHING

All that is, except for the baby -
who just gets a soaking.

SCREECHING

It seems likely that baboons don't
much enjoy being in the water -

or they may be nervous of
something in it.

Crocodiles are everywhere.

For the troop,
a flooded Delta is a lawless place,

but a threat worse even than
a crocodile has appeared.

Lone male baboons.

The shrinking of territory on land

forces the loners into contact
with troops.

They may fight the troop's
alpha male for control.

If the stranger wins,
he may also kill the young

and mate with the females.

An incumbent alpha male must keep
a close eye on any rival.

HE BARKS

To survive, it is crucial that
he lay down his authority.

BARKING AND GRUNTING

GRUNTING

ROARING

SCREECHING

ROARING AND BARKING

SCREECHING AND ROARING

BARKING

GRUNTING AND SQUEALING

SCREECHING AND SQUEALING

GRUNTING

Insurgents must be sent packing.

As the Delta floods, everywhere,
tension seems to be mounting.

Not least in the hippo community,

where their watery territories
are expanding dramatically.

Here, too, there is
a young challenger.

The territory's resident bull
snorts a warning.

HE SNORTS

The adversaries declare
their ownership of the pool

by vigorously spreading dung
with their tails.

SNORTING

They yawn to display
their weaponry -

huge ivory tusks.

SNORTING

First, a test of strength.

SNORTING

The old bull makes
a temporary retreat.

Females have a vested
interest in the outcome.

They will only be prepared
to accept a mate

that can hold his own in a fight.

The resident bull
retaliates brutally.

SNORTI NG

SNORTI NG

Hippos will often fight for hours
and sometimes to the death.

Finally, a brutal headlock -
the coup de grace that settles

it for the older male -

expelling the pretender
from his territory.

Which means the resident bull
passes the test

to sire this year's
crop of baby hippos.

GRUNTING

The young male has been
injured during the retreat,

his flank exposed
to his furious pursuer.

At least nature has arranged for him
to be nursed - by these oxpeckers.

They eat anything that might
cause an infection.

The pain is probably worth it

and he should survive
to fight another day.

By August, the floodwaters
finally reach

the Delta's southern fault line,
its maximum extent.

The Okavango is now one of the
largest inland deltas in the world.

The whole Delta is linked by water -
shallow flood plains, pools,

and deeper channels all fed
by the Okavango River.

Billions of fish that fill
the plains have grown rapidly.

And Sinabe's wives and daughters are
ready for them with their baskets.

SINGING IN AFRICAN LANGUAGE

SINGING CONTINUES

SINGING STOPS

Bulldog fish will make a fine stew.

In the main river,
something strange is happening.

The waters appear to be boiling.

It's catfish,
taking gulps of air at the surface.

And they are here
in their millions.

Before the flood recedes, they
return from their hunting grounds

in the far reaches of the Delta to
the safety of the deep channels.

Amongst the papyrus,
they hunt smaller fish.

Flocks of egrets arrive
to join in the feast.

No-one is safe in the mayhem.

African fish eagles swarm
and dive-bomb the catfish.

Millions of fish that grew fat
out in the flood plains

bring life back to the river
that brought them water.

When it's needed most,

the flood creates a vast oasis
in the desert - a wonderland.

Its 10,000 square kilometres
of crystal waters

attracting animals from all over
the dry Kalahari desert.

HE ROARS

HE ROARS

But these waters will never
reach the sea.

They will soon begin to evaporate or
simply sink into the Kalahari sand,

as the Okavango Delta
gradually returns to dry savanna.