All language subtitles for Zambezi BBC Natural World 2012 HDTV_Subtitles01.ENG

This is the least known
of Africa's great rivers.

The Zambezi brings life
to six countries

and its reach spans half a million
square miles of southern Africa.

It's a river of thrilling spectacle

and wild surprises.

At times, the Zambezi's power
can be almost overwhelming.

Yet it can be just as challenging
when its waters all but disappear.

The fate of all life here is at
the mercy of the ever-changing moods

of this great river.

In April, half a million
tons of water

pours over the Victoria Falls
every minute.

Just a few months later,

the Zambezi's most famous
landmark has dried up.

By September,
the drought is so intense

that for much of its course, the
river has shrunk to almost nothing.

This leaves a great swathe
of south-east Africa

deprived of its life-giving waters.

During the wet season,

the Zambezi flows for 1,600 miles

from its source
in the Zambian Highlands

to the coast of Mozambique, where it
empties into the Indian Ocean.

But by the end of the dry season,
the river barely flows at all...

leaving the land at the mercy
of a blistering sun.

The dwindling river draws in
thirsty animals from near and far.

Its banks see a constant flow
of traffic.

The desperate search for food

can keep elephants away from
the river for days at a time...

..which must make their brief
return visits all the sweeter.

Buffalo put in
more regular appearances...

..dipping into the river
morning and evening.

Hippos are even more
tightly bound to the river.

As the Zambezi shrinks,

these dedicated bathers
are forced to crowd together

into what pools remain.

HIPPO GRUNTS

They've spent the cooler night
wandering the banks looking for food.

Daybreak sees them
heading back to the river.

HIPPO GRUNTS

Hippos have thick, blubbery skin

and no sweat glands.

So overheating can be a real problem.

Wallowing through the heat
of the day is one way

to help them keep their cool.

One hippo is late back
from its nocturnal wanderings,

only to find its way
to the river barred.

These hyenas are really
pushing their luck,

picking on such an enormous victim.

But when times are tough,
no opportunity can be overlooked.

HYENAS SCREAM

Hippos only feel safe in deep water.

But this late in the dry season,

that's a commodity
in very short supply...

..forcing thousands to share
the narrowing channels

that feed the Zambezi.

This stressful overcrowding
leads to fighting

and the inevitable casualties.

The smell of death draws out
the river's scavengers.

Within a few hours,

over 100 crocodiles have converged
on the carcass from far and wide.

The younger ones hold back,
while the larger crocodiles

squabble over the choice cuts.

Crocodiles are true survivors,
able to go for months between meals.

So this one chance to feed
will be enough

to get many through the hard times.

Others too are reaping the benefits
of this overcrowding.

Wherever there are hippos,
there are oxpeckers.

The hippos tolerate these birds
because they remove ticks

and other skin parasites.

Their habit of picking at old wounds

to lap up fresh blood
is much less friendly.

And hippos aren't the only choice
open to these freeloaders.

Buffalo are plagued by their
attentions, as they poke and probe,

feasting on bugs,
dead skin, saliva...

even earwax.

Six months ago, these mud banks
were completely underwater.

But as the river level has dropped,

carmine bee-eaters have moved in

to stake their claims.

Each nest hole must
be dug anew each year,

after the Zambezi has reshaped
its banks during the flood season.

Some colonies may contain
several hundred pairs,

all crowded together for safety.

But the adults are still
vulnerable to aerial attack.

An African fish eagle
has taken up residence.

And it's developed
a real taste for bee-eaters.

BIRDS CHIRP

Its feet are designed
for grappling with slippery fish,

but they're just as good
at snatching panicking birds.

It's another
of the Zambezi's residents,

adaptable enough to make the most
of any chance that presents itself.

By October, the river has
pretty much reached rock bottom.

Out on the Zambezi's floodplain,

the intense heat is sucking
the last water holes dry.

This warm, muddy water holds
little oxygen for trapped catfish,

but asphyxiation is the least
of their problems.

Marabou storks gather
around the shrinking pool.

Smaller catfish can burrow
into the mud to escape

and will even travel short distances
over land to reach new pools.

But the larger ones
have nowhere to hide.

In the heat, their fate is sealed.

Several hundred miles further inland,

and upstream from the Victoria Falls,

the situation around the Zambezi
is just as desperate.

Along the river's banks,
the land is turning into a dust bowl.

As the grass withers and dies,
there's little left to eat.

Everything is hanging on,

hoping the river will soon
revive their fortunes.

Wandering guinea fowl disturb
a pack of hunting dogs.

The birds are of only
passing interest.

These dogs are after bigger prey.

The pack exchange greetings as they
steel themselves for the chase.

The dogs have been waiting
for the cool of the evening...

but now it's time.

The pack is led by an alpha pair.

They decide when to move
and what to hunt.

As they close in, the pack splits
up, trying to outflank their prey.

Impala have speed.

But the dogs can run
at 30 miles an hour...

..and have incredible stamina,
as well as guile.

In their panic, the impala
runs straight into the trap.

DOGS WHIMPER

Three quarters of
all wild dog hunts end in a kill.

A group this size
needs to kill every day.

And a river-side territory
means they fare better than many.

Away from the river,
the land is parched.

Life is a challenge
for even the biggest

and smartest of
the Zambezi's inhabitants.

With the river side
vegetation exhausted,

hungry elephants have been
forced away from the river

in search of food.

They can't afford to ignore anything.

Even a toppled tree
gets the herd excited.

Little ones need to learn
these twigs are edible

and some moisture can still
be found in the bark.

But the adults need up to 200 kilos
of forage every day...

..and lots of water to help
digest such a high-fibre meal,

which means repeatedly trekking
back and forth to the river.

Three or four days without a drink
is just about their limit.

Local knowledge can make
all the difference to survival.

It's intelligence
the herd matriarchs have accumulated

over decades of wandering the plains.

Young calves begin to absorb
this survival know-how

as they march at their mothers' side.

A fully grown elephant can easily
drink 100 litres of water

in a single visit.

There's little time to linger,

although some seem reluctant
to leave the comfort of the river.

But soon, this ordeal will be over.

The mood of the Zambezi
is about to change.

The first signs of that change

can be seen above the rolling
hill country of northern Zambia.

The Kaleni Hills rise just
1,500 metres above sea level,

but they are the green heart that
will pump life back into the Zambezi.

Above these hills,
powerful and opposing trade winds

begin to converge.

These collisions generate huge
thunderclouds and torrential storms.

These first downpours
mark the rebirth of the Zambezi.

From these hidden springs,

the great river begins
to trickle its way to the sea.

As the streams combine,

the rejuvenated Zambezi
begins to gather strength

as it curves westward into Angola.

These forest glades are the last
stronghold of giant sable antelopes.

The darker males
carry huge, curved horns

that can grow
to over a metre and a half.

For 30 years, there were
no sightings of these animals.

Then, in 2005,

this one herd was rediscovered.

With only a few hundred left,

every new addition helps bolster
the sables' dwindling numbers.

For the moment at least,
these highly-endangered antelopes

have found a sanctuary
on the banks of the Zambezi.

As the river swings back east
and re-enters Zambia,

it leaves the sable
and the forests far behind.

The growing Zambezi begins to wind
its way across the Barotse Plains.

These first rainstorms
have partially refilled

some of the long-dry water holes.

After months on the move,

the pressure on the great herds
of buffalo finally eases.

As the plains turn
from brown to green,

the buffalo can settle down to
the serious business of eating,

spending up to 18 hours every day
grazing the new grass.

The Losi people have lived alongside
the Zambezi for generations,

adapting to it many moods.

Before the water levels begin
to rise, there's time to visit

a favourite fishing hole to plunder
the last of the trapped catfish.

Soon, this grassland
will be unrecognisable

and the Losi will be forced
to move on to pastures new.

They will not be
the only ones on the move.

As the rains gather in strength,

others are being drawn
towards the Zambezi.

Small groups of blue wildebeest
begin to arrive,

after a 200-mile journey
south from the forests of Angola.

30,000 will eventually gather here.

It's one of the largest,
yet least known migrations in Africa.

They are here to graze
the fresh grass...

and to calve.

Almost all wildebeest calves
are born within a three-week period,

flooding the Zambezi's plains
with new life.

But they have already attracted
some unwelcome attention.

A clan of hyenas begin
to shadow the growing herds.

Their hunting strategy is simple...

Get the herd moving.

Look for a weakness...

..then strike.

The hyenas move in amidst the chaos,
searching for a victim.

The calf makes it back
to the safety of the herd.

Its mother is not so lucky.

The clan soon gather around
the downed wildebeest.

Despite having so much choice,
nothing is wasted.

All too soon,
the wildebeest will move on.

And the hyenas' time of plenty
will disappear.

By January, the storms
are coming thick and fast.

The river channel
can barely contain the torrent.

After months with so little water,

the Barotse's residents
are about to be confronted

by a very different Zambezi.

The flood surges out
over the river banks,

inundating thousands of square miles.

Almost overnight,

the grassy plains are transformed
into a shallow inland sea.

More migrants arrive,
following the advancing flood...

..their growing numbers adding

to one of the greatest gatherings
of birds anywhere on the planet.

The rising water has suddenly
got everything on the move.

Insects, frogs and fish
all make their way

onto the flooded plains to breed.

Easy pickings
for the hordes of water birds.

Even ground hornbills take advantage,

stalking the shallows.

Spoonbills sift the grasses
for snails and minnows,

while yellow-billed storks
tackle bigger fish.

But while
these new arrivals make merry,

others are now forced to move on
as the waters deepen.

The buffalo herds bulldoze
their way towards higher ground.

The blue wildebeest
continue their wanderings.

It will take five months for them
to complete their return journey

back to the Angolan hills.

Lechwe antelope are in their element.

Strong swimmers,
they never stray far from water.

But even they must move
to keep pace with the rising tide.

The relentless Zambezi forces both
predator and prey into full retreat.

April marks high water
on this stretch of the Zambezi.

The river's floodplain
is now 20 miles wide.

It takes weeks for the floods
to cross these flat expanses,

as if the river is drawing breath
before plunging on toward the sea.

The Losi too have learnt to adjust
to the rhythms of the great river.

Their villages first
become waterlogged...

..then, gradually, submerged.

Soon, they will abandon their huts,
driven out by the rising tide.

But they can't just
up sticks and leave.

By tradition, they must first wait
for the signal from their king.

Today has been decreed as
the moving day - the Kuomboka.

The word means literally
"to get out of the water."

CHEERING

It marks the time when the entire
community moves to higher ground

and in some style.

An elephant decorates
the King's barge.

A crane perches on the roof
of the Queen's.

100 men peddle each of the royal
barges across the flooded grasslands.

It takes hours in the boiling heat

and humidity to reach their summer
villages on the edge of the plains.

The Losi may be away
for six months or more,

but it's a disturbance
well worth putting up with.

The silt left behind
after the floodwaters recede

invigorates the plains, preparing
it for the returning villagers

to plant their crops
and graze their animals.

The Kuomboka is a celebration
of the gifts the Zambezi brings

to this part of Africa

and of how much the rise and fall
of the river dictates life here.

For now, the Losi villages stand
empty, deserted by the people

and their livestock.

But there is life here still.

New lodgers flood
into the abandoned settlements.

Carp, minnows and cichlids pick over
the remnants of village courtyards.

The flooded houses make perfect
breeding grounds

for many Zambezi fish.

Others use them as shelter
from predatory tigerfish.

But stray too far from cover

and there are other hunters
waiting to drop in.

Able to hover and eat on the wing,

pied kingfishers
are perfectly at home

fishing over the flooded grasslands.

As the floodwater finally
reaches the southern end

of the Barotse plain,

it is gently funnelled back
into the main channel of the Zambezi.

Now, over 700 miles from its source,

the great river gathers itself
for the next stage of its journey.

Heading east again,
the Zambezi begins cutting through

the tough volcanic
rocks of the Tonga Plateau.

Ahead, a cloud rises
half a mile into the sky.

It's not smoke from a bushfire,

but spray.

Visible from 20 miles away,

this cloud signals the most famous
landmark on the Zambezi.

This is Mosi-oa-Tunya -

the smoke that thunders.

To the wider world,
these are the Victoria Falls.

In full flood, this is the largest
sheet of falling water in the world.

Over half a million cubic metres of
water pour over the lip every minute.

At this time of year,
the falls are over a mile wide.

And the cascade throws up
enough spray to sustain

a unique rainforest
along the Zambezi's banks.

Once the surge has passed,
the local fishermen move in to try

their luck, in what must be the most
exclusive fishing holes in the world.

Generations have made the precarious
journey out to this pool.

One false move and it's a drop of
over 100 metres onto the rocks below.

The Victoria Falls
are a pivotal point on the river.

From here, the Zambezi leaves
the wild plains far behind

and powers on towards
a new and very different world.

Below the falls,
the river cuts through

the first of several deep gorges.

The Zambezi is squeezed
into a channel just 100 metres wide.

The power
of the compressed river is immense.

Over millions of years,

this slow attrition has carved
a series of steep-sided canyons.

Deep and inaccessible, these gorges
have been cut a centimetre at a time

by the raw energy
of the river in full flood.

For over 100 miles,
the Zambezi zigzags its way east,

driving on towards the coast.

But as the river bursts from
the last of these canyons,

the current slackens

and the flood lost in
the deep waters of Lake Kariba.

Over 180 miles long, this is
one of the largest lakes in Africa.

But only 60 years ago,

these islands were hilltops, because
this lake is a recent addition

to the Zambezi's ancient course.

Holding back all this water
is the Kariba Dam.

It was the first of several huge dams
which now help control

the flow of the Zambezi...

..converting the elemental energy
of the river into electricity

for Zambia, Zimbabwe
and South Africa.

After the dam was completed in 1959,

it took just four years
for Lake Kariba to fill.

As the waters backed
up behind the new dam,

a massive rescue mission
known as Operation Noah

was mounted to help animals
caught out by the rising tide.

A group of dedicated
wildlife rangers

moved in to deal
with the stranded animals

ELEPHANT TRUMPETS

Larger animals were sedated...

..then moved to newly-established
national parks along the lake shore.

Small animals
were stampeded into nets.

DEER WHINE

It was a dangerous business
for all involved.

It was the first time
such an ambitious wildlife rescue

had ever been attempted,

but Operation Noah
was hailed as a triumph.

Over five years,

more than 6,000 animals
were removed to safe ground.

RHINO GRUNTS

RHINO ROARS

Although clearly some were
less than grateful for the efforts

made on their behalf.

RHINO ROARS

While the rescued animals
lived to fight another day,

the dam itself changed
the Zambezi's character forever.

Robbing the river of much
of its essential wildness.

Today, the seasonal floods
on the lower reaches of the river

are no longer dictated by nature,

but largely controlled by engineers.

Yet enough water
is still released from the dam

to keep the river flowing

and every rainy season, the Zambezi
spills out of its main channel

and floods into a series of
ancient lakes and stream beds.

These are known as the Mana Pools.

ELEPHANT GRUNTS

The barren earth
bursts into life with grasses

and seeds that
have lain dormant for months.

This flush of green
draws in game animals

all along the fringes of the river.

Young hippos hide away
in the quieter backwaters.

Many of these pools are now choked
with water hyacinth, a fast-growing,

invasive weed, introduced from
the Amazon in the 19th century.

But these floating mats
block out the light

and starve the water of oxygen,
choking all other life.

Although hippos and elephants
seem to adore it.

So the more they can eat, the better
it is for the health of the pools,

but they have quite a job
on their hands.

The flooding draws even reluctant
bathers into the water.

INSECTS BUZZ

Baboons certainly don't
enjoy getting wet,

but the chance to feast on snails
and flowers proves irresistible.

Along the tree-lined banks,
other Zambezi residents

seem much more at home.

Fish eagles don't miss a trick.

With the bee-eaters long gone,
they have turned their attentions

to the shoals of fish
that gather in the shallows.

They can even turn the tables

on the tigerfish, one of the most
voracious of the Zambezi's predators.

BIRDS SQUAWK

For a brief moment, the flooded
pools are a magnet for many

along the stretch of the Zambezi.

Smart hunters stake out
the water holes.

Waiting and watching.

These buffalo are nervous.

They sense something is not right.

They hightail it for cover.

When threatened, buffalo
bunch in a defensive group,

with the calves gathered together
and larger adults running shotgun.

The lion is persistent,
but when he catches up,

one of the herd's enforcers
proves more than a match.

The rest of the herd
move in as back-up.

Buffalo are notoriously bad-tempered

and quite capable
of dispatching a lion.

But today, it's only his pride
that's been injured.

After months of rain, the Zambezi
is about to change moods once again.

Storm clouds still
build over the river each afternoon,

but these last downpours
have lost much of their power.

The rain does little
but kick up the dust.

ELEPHANT GRUNTS

All along the Zambezi,

animals once again start preparing
for harder times.

But on one of the river
terraces, a rare treat.

An ancient fig tree
has burst into fruit.

A Trumpeter Hornbill shares
the figs with a troupe of baboons.

Fig trees can crop
at any time of the year

and these fruits
always attract a crowd.

As the heat intensifies, acacias
begin shedding their seed pods.

These are irresistible
to bull elephants.

In a good year, one tree
may produce 300 kilos of seeds.

For the tree, it's a great way
to spread its seeds.

For the elephants,
these are rare and welcome morsels,

packed full of energy.

It's a chance for everyone
to stock up.

There are no giraffes here,
so every extra centimetre gained

gives these bulls
exclusive access to more food.

But it can be
a precarious balancing act.

Some elephants go to extraordinary
lengths to reach the best leaves.

ELEPHANT ROARS

Bulls can weigh over 5,000 kilos

and these acrobatics
must place immense stresses

on their spine and legs.

But it's worth the risks to gather in
the last of the greenery.

Soon, life all along the Zambezi

will become much more challenging,
as the dry season begins to bite.

Beyond the Mana Pools,
the river continues eastwards

through an ancient rift valley,
heading towards Mozambique.

The Indian Ocean is only
a few hundred miles distant.

But already the water level
in the river is dropping.

HIPPO GROANS

Once again, hippos begin crowding

into the deeper stretches of
the Zambezi and its tributaries.

Adults tend to hog
the deeper parts of the river

and the youngsters have learnt
to give them a wide berth.

They form their own gangs
on the fringes,

where their curiosity can get
them into all sorts of scrapes.

In the main channel, a dominant bull
controls each stretch of deep water.

He will tolerate others,

as long as they behave
themselves and defer to him.

This muck flinging
is all about intimidation.

Crowded together, cheek by jowl,

it's only a matter of time
before tensions erupt.

The shockwaves ripple down the line.

Once the pecking order is restored,
everyone settles down,

but there's unfinished business here.

Fights can last for hours
and if opponents are well matched,

can be to the death.

The dominant male has reasserted
his right to be the leader

and so monopolise the females
along this stretch of river.

For a while longer, elephants
can still take things easy.

ELEPHANTS RUMBLE

The bank-side vegetation
is not yet exhausted,

so they can stay close to the river.

There's even the odd moment
for them to indulge themselves.

River mud makes an excellent screen
against the blistering African sun.

This very young calf
is none too steady on its feet...

..and soon needs rescuing
by its ever-attentive mother.

Elephants are great swimmers.

River crossings hold few fears.

Their snorkels allow them to continue

even when fully submerged.

There's time to spend a few minutes
enjoying each other's company

and the cool of the water.

Soon, life will become
much more serious.

As food becomes harder to find,
the elephants will again

be forced to spend more and more time
away from the river.

As times get tougher,
the Zambezi will once again become

the vital lifeline
on which all can depend.

After 1,600 miles,

the Zambezi is nearing the end of its
epic journey across southern Africa.

Here, on the flatlands of Mozambique,

the great river mellows as it
begins to divide into a maze

of smaller channels.

As the flow eases, silt carried
from the heart of Africa

begins to settle

creating a huge delta that
reaches out into the Indian Ocean.

Today, this delta covers
over 4,000 square miles,

but just 60 years ago,
it was twice this size.

This dramatic decline is due mainly
to the huge amounts of water

being held back
by the many dams upstream.

Yet the river still empties
vast quantities of fresh water

into the Indian Ocean.

But even as this mixes with the salt
water, its journey is not over.

Already, the heat of the sun
is sucking droplets

back up into the sky.

These clouds are carried
far inland by the trade winds,

where they release
their precious cargo as rain.

Rain that replenishes
the flow of the Zambezi,

and so continues
the endless recycling of water

that is so crucial to life.

Despite our best efforts
to tame its many moods,

the Zambezi remains one of Africa's
greatest and wildest rivers.

Subtitles by Red Bee Media Ltd