Original subtitles

Narrator: In the dry-lands of South Africa,

where heat and thirst are a constant,

there's an alien world seemingly void of life.

But a line runs through it,

Where nature abounds.

A waterway of immense proportions -

Breathing life into the desert.

This is the pilgrimage of the Orange river -

the journey of the Linear Oasis.

Stretching over 1,200 miles,

the Orange river is the longest in South Africa.

Flowing west towards the cold Atlantic Ocean,

it bisects Lesotho

and then forms South Africa's border with Namibia.

In its lower reaches it's a mammoth force,

Forging its way through rock and sand alike.

Alternating between angry, abundant might -

And slow lethargy.

The Orange river is an iconic landscaper

across the southern tip of Africa.

But the river has humble origins

in the mountain peaks of Lesotho.

It begins as just a trickle.

Or rather, many trickles.

The river starts nearly 10,000 feet above sea level,

in the Maluti Mountains.

Up here in the clouds, rainfall is abundant.

It doesn't take long for trickles to become streams.

And for streams to become rivers.

The catchment area here is vast

- with multiple watersheds

channeling many young rivers into one another.

In these early reaches the river is known as the Senqu -

named by the Sesotho inhabitants of the area.

On leaving Lesotho,

the river bends out into the interior of South Africa.

It's here that it joins forces with its main tributary,

the Vaal.

The Vaal river has been working its way south west

for over 600 miles.

The two rivers merge in South Africa's Northern Cape province.

From here, they continue their journey westwards

towards the Atlantic Ocean,

crossing two thirds of the country with renewed strength.

Despite having sources so close to the east coast,

both rivers flow west -

making their journey to the sea a long one.

This is a result of tectonic uplift

that blocked their flow east

and channeled both rivers into the basin of the interior.

550 miles from its source,

the newly merged Orange river

attracts a diverse range of life.

The day is young but the avian residents are already busy.

Birds flock to its waters,

attracted by the numerous fish, crabs and frogs on offer.

Water birds have already taken their first swim

and wait patiently to catch the first rays of light

after a cold morning of fishing.

Others let their meals come to them.

Floating islands of vegetation drift idly downstream.

For the birds it's a mobile buffet -

transporting various marooned insects down the river.

Wagtails pick their breakfast off with ease,

enjoying a ride as they forage.

The African darter is one of the bigger personalities here.

It's also one of the best swimmers.

They move using foot-propulsion,

usually with only their long neck visible above the water.

This has earned them the colloquial name,

the 'snakebird'.

A male's on the hunt for fish.

He will spear his prey before bringing it up to the surface

to shake it off his bill tip and into his mouth.

This tricky operation requires some practice.

Patrolling above is the avian authority on fishing

the African fish eagle.

The darter must be wary.

The great eagle is not averse to stealing somebody else's catch.

With such riches on offer,

fights for territory often break out.

An aerial dogfight falls from the sky.

The highly territorial Egyptian geese

will fight to the death for this stretch of river.

But their racket draws unwanted attention.

The fish eagle sees the distracted geese

as a chance for an easy meal.

A close call.

It appears his eyes are bigger than his stomach.

The river courses with fishermen in many forms.

One of the most elusive predators

moves quickly and quietly,

flipping rocks and feeling for crabs along the shallow banks

of the Orange river.

The Cape clawless otter.

Characterized by its partly webbed, clawless feet,

its diet includes crabs, fish, frogs and even worms.

They use their extremely sensitive whiskers

as sensors in the water

to pick up the movements of potential prey.

Their front paws come in handy

when digging on the muddy bottoms of ponds and rivers,

picking up rocks and looking under logs.

They're playful creatures and enjoy foraging as a group.

With plenty on offer in the Orange river,

life thrives in large numbers.

Through its upper reaches

the Orange river cuts through a range of habitats.

The morning light begins to slowly heat the granite boulders

along its banks,

Enticing some hairy inhabitants

to emerge from between the cracks and crannies.

The Rock hyraxes are awake.

As they do every morning

the colony assumes strategic positions on the boulders,

soaking up the warm, golden light

and generating some energy for the busy day ahead.

Although, hyraxes are rarely busy.

Rock hyraxes rest most of the time.

This is especially true for the adults -

who enjoy a late morning sleep on the warming rocks.

Although they resemble rodents,

hyraxes are in fact relatives of the modern-day elephant -

evidenced by their pointed tusk-like upper incisors.

The soles of their feet have large, soft pads

that are kept moist by sweat-like secretions.

Among the vigilant adults are several babies.

They too clamber out of the fractures

to soak up a bit of sun -

making good use of their mother's soft fur.

Finding a position that suits everybody

can be a difficult task.

Finally, the family unit absorbs the suns energy in a big pile.

The peace is short-lived.

For the youngsters, there's fun to be had.

After breakfast it's time to explore their surroundings.

Hyraxes are expert climbers

and the babies, albeit not as skilled as their parents,

are fast learners.

They clamber around the rocks with ease -

often jumping surprising distances.

As the river continues to flow westward

on its journey to the Atlantic

it winds up towards the border of Namibia,

where it cuts through the iconic Augrabies National Park.

Here, the river splits and reforms - creating islands,

smoothed and polished by the vigorous water

over the millennia.

Over time the river has cut a deep gorge

into the ancient granite rock.

Gone is the calm, amicable river.

Here the Orange shows its true strength

in an angry display of white water.

The river twists and turns through the gorge

before blasting over the edge of a 475 foot drop -

the Augrabies falls.

Taking its name from the local Khoikhoi language,

"Ankoerabis" means the place of big noises.

Mist rises up from the gorge -

spraying the sun-soaked rocks above.

Small black flies swarm in their millions

and provide an abundant food source for some lucky predators.

Scores of Augrabies flat-lizard emerge from the numerous cracks.

The females are drab in color,

sporting only the intricate patterns

down the length of their spine.

The male lizards however,

are brightly colored - with personalities to match.

They use these colorful scales to signal dominance

and settle territorial disputes.

When they aren't busy catching flies

the males try to outbid each other for prime patches of rock.

Assuming the push-up position, they assert their dominance

by showing off their bright blue belly.

This male has found an unwanted contemporary

in his stretch of territory.

A face-off ensues.

Circling each other,

the males flip their bellies up from the side

to show off their colors.

If this isn't enough to scare off the intruder,

drastic measures must be taken -

a good old-fashioned fight.

Their colors aren't only to warn off other males.

Females that move through their territory

immediately attract interest.

The males try to garner affection

by walking around the females

in an almost robotic, plodding motion,

showing off their colors.

This male has been trying all morning.

His approach seems spot on,

but his follow through leaves something to be desired.

A sharp bite on her tail is not appreciated.

With another courtship gone to waste

he returns to his quest for food.

Crossing the entire width of Augrabies National Park,

the Orange finally emerges from the rocky ravine

and spills out onto the land.

Here the river begins to support more and more vegetation.

As the landscape blends from boulder to bush,

it attracts a myriad of larger residents.

A family of giraffes moves over the jagged landscape,

looking for food.

They seem out of place in this rocky environment.

The giraffes have no predators here

and roam freely, without worry.

Unlike the giraffe, Klipspringers are agile climbers

and clamber over the crags with ease.

And their dappled brown coat

helps to blend them into their background.

But they still must be wary.

A male Klipspringer is on the watch for predators.

And for good reason,

he has young to look out for.

A sub-adult has joined the family.

An extra pair of eyes is invaluable

when danger lurks all around.

A pair of Verreaux's eagles patrols from above.

A baby Klipspringer would make an easy meal -

but the hunters' presence doesn't go unnoticed.

The Klipspringers stick close to the rocks,

which offer both camouflage and shelter.

The vegetation even entices the resident hyrax

away from the refuge of their boulders.

The babies learn to forage by imitating their parents -

they're learning fast.

And like the Klipspringers they too must be vigilant.

A sentry sounds the alarm.

The hyraxes scatter quickly -

abandoning their feeding grounds

to take refuge amongst the crags.

Today, the eagles will go hungry.

Many eyes make life a little easier.

1,200 miles into its journey,

the Orange river enters the Richtersveld.

This is an arid region,

consisting of mountain deserts and sandy plains.

Though at its widest here, the Orange river does little

to quench the Richtersveld's dry environment.

Hundreds of miles downstream, a far stronger body of water

exerts a much greater influence -

one that leaves this landscape dry.

Cold water coupled with the strong winds of the area,

prevents onshore air from accumulating much moisture.

Thus, the land flanking the ocean is a dry and barren place

and moisture from the river does little to quench its thirst.

So just a few hundred feet away from the banks of the river,

the land is parched .

The landscape resembles a hot, lonely planet

one void of life.

But nature finds a way, even here.

An alien plant - dry and cracked, reaches up to the sun.

Its branches, bulbous and bent.

Its leaves, tough and juicy.

This succulent plant is a species of aloe tree -

one of three species that occur in this area.

Its name, the Quiver tree, comes from the indigenous San people,

who used its branches as quivers in which to carry their arrows.

Many of these specimens are over a century old.

Their reflective, waxy bark

helps them survive in this harsh environment.

Like their succulent leaves,

the bark helps to minimize water loss.

There is little relief for the inhabitants of the Richtersveld.

Extreme conditions require extreme adaptations.

This spiny fat arm belongs to the Halfmens -

which means 'half-human'.

These strange plants have an ominous story.

Legend has it that the Halfmens are lost members of a tribe

that escaped Namibia after a terrible clash with invaders.

After fleeing south and crossing the Orange river,

they ended up scattered in the never-ending hills

of the Richtersveld.

Their hopes of ever returning home were dashed,

when their god turned them into thorny plants -

destined to stare longingly to the north,

where the land of their ancestors lies.

In these lower reaches, the river is known as the !Gariep -

which means 'great river' in the local Nama language.

The Nama have traversed this region for centuries -

their ancient etchings

remain on the numerous rocks that scatter the Richtersveld.

But the stones themselves tell a much older story.

These rocks were forming before Africa even existed.

Their geological beginnings stretch back two billion years -

almost half the age of Earth itself.

Continuous volcanic activity and successive intrusions

have left a landscape consisting

of more than 10 separate geological groups.

This complex geology provides diverse habitats

where an array of plant and animal species can thrive.

Creatures slither and creep through the rugged terrain.

Even here, Klipspringers easily navigate their way to food.

A family of Cape ground squirrels

searches among the stones for insects.

Separated from the river by the Richtersveld's jagged mountains,

there's nothing for them to drink

so they have to get their daily water from the food they eat.

While the family forages - a guard keeps a look out.

Staying close to the burrow is a good bet for safety.

Lying on the plains

are the quartz fields of the Richtersveld.

Over the millennia, large, fractured rock has broken down

to form a beautiful carpet of white pebbles.

Between the stones

are some of the best examples of succulent diversity

in southern Africa.

Each plant stranger than the last.

Some make use of camouflage -

mimicking the gravel that lies around them.

But one rock seems livelier than the rest.

A Stone grasshopper moves amongst the pebbles.

His textured exoskeleton

leaves him all but invisible to potential predators.

The landscape has become his greatest defense.

Occasionally a small amount of water

does reach the highest mountaintops

in the form of mist.

And when it does

it provides plants and animals with enough moisture to exist.

Bulbous Butter trees grow

and flowering plants add a magical splash of color.

Though far from abundant,

this water leaves its scars on the rocky plains below.

Dry riverbeds stretch across the stony flats -

carved into the earth

by the rare flash floods that occur here.

Small holes pepper the baked earth of the dry riverbank.

One by one, hundreds of Brown-throated martins

shoot out of their nests.

These inconspicuous little birds

start their morning with a bit of sun soaking

and a social catch-up.

There are few places to perch here - and each spot

is highly contested.

Having secured a spot it's time to get every feather in place.

Once preened to perfection they can test out their wings.

The martins are highly sociable

and enjoy a spot of playful flight.

Constantly communicating,

the twittering chatter of the birds fills the air by the nest.

But danger lurks.

In the heat of the day, an ominous character appears

from out of a dark cave in the riverbank.

A Nile monitor: a formidable predator.

Using his forked tongue to sniff the air -

he gathers information about potential meals

that may be nearby.

Nile monitors are not fussy eaters

and they love birds' eggs.

But being ectothermic,

he must warm up before attempting any activity.

Today is apparently not the day to go hunting.

Having caught enough sun for now,

the monitor returns to his cave.

The martins however are ready for action.

Their destination

the Orange river.

Martins are usually found foraging near water.

Their short, wide bills

are the perfect tools for snatching up tiny insects.

These small birds show extreme dexterity on the wing.

And miraculously avoid mid-air collisions.

In its last few miles

the river reaches its final stages and approaches the coast.

Signs of the oceans presence start to appear on the hilltops.

A mystical tapestry covers the land,

showing signs of relief.

These are the lichen fields of Alexander bay.

Lichen is neither a plant nor an animal.

Rather, it's a community of microscopic algae and fungi,

living together in symbiosis.

In amongst the fuzz,

strange plants grow in the protection

of this rusty green blanket.

As do many small, inconspicuous creatures.

Lichens thrive here because of a source of moisture

that rolls in from the sea.

When the ocean fog arrives, it comes in thick and fast.

Within minutes,

it can block out the sun and envelope the lichen fields.

Bringing life to the plants

and the collection of strange residents

that call these fields home.

After a 1,200 mile journey

through ever changing landscapes

the Orange river finally purges its contents

into the Atlantic Ocean.

The river discharges almost 3 billion gallons of water a year.

Having travelled across two thirds of South Africa,

the great Orange river fans out into its delta

before spilling into the sea.

Flamingoes and water birds flock to the mouth

to sift through the nutrient-rich waters.

The Orange river has traversed

an entire continent on its journey.

And has run a lifeline

through some of South Africa's harshest environments.

From source to sea,

it has played host to countless wild and wonderful creatures.

And left its scars on rocks that have born witness

to the geological history of Africa.

In a land without relief

This waterway is a welcome gift

to South Africa's thirsty inhabitants.

Breathing life into the desert,

the Orange river is a sanctuary,

a Linear Oasis.