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Africa is a land of giants.
Vast landscape sculpted by impressive rivers, massive waterways, home to
magnificent creatures as powerful as the rivers themselves.
Their extreme living conditions test the strength and survival skills of
the large inhabitants.
These are Africa's awesome Rivers of Giants.
Africa's most impressive animals are the elephants, hippos and crocodiles,
all water dependent creatures that need giant size waterways to survive.
Their habitat once stretched along most of Africa's rivers from the far
north to the extreme south, but today their range is limited and these are
seven of their last remaining safe havens.
South Africa's Pongola and Sand rivers, Southern Africa's Limpopo,
Namibia's Hoanib, Tanzania's Rufiji, Uganda's Victoria Nile and Gabon's
Ogooue.
In Southern Africa, the Limpopo marks the border between South Africa,
Botswana and Zimbabwe.
It originates in a city and broadens once it flows through the wildlife
rich sanctuary of the Tuli Block in Botswana.
Here, the Limpopo is a true giant and it supports an impressive range of
titans.
The elephant, the largest mammal on land, the python, the largest snake in
Africa, the leopard, the largest spotted cat, and the civet, the
largest member of the mongoose family
During the dry winters, the river shrinks dramatically and the
surrounding land becomes barren and dry.
The animals are forced to leave their summer grazing grounds and move to the
river's edge.
The Limpopo's largest giants, the great herds of elephants, are regular
visitors.
They adapt to a wide range of habitats, varying from Savannah plains
to dense forest.
The one thing they depend on to survive is a permanent source of
water.
Then it's off to the soft sandy banks for a sand bath.
This natural remedy protects their skins from the sun and suffocates
parasites.
While the older elephants indulge in skin care, this four month old baby
practices the mechanics of trunk control, not an art form that comes
naturally.
After a few hours, the herd's daily river routine is over.
At the senior cow's signal, the elephants move on to feed.
They leave behind the Limpopo's most skillful hunter, the python, a snake
equally at home in a tree, as it is in water.
It's a patient predator that can wait motionless for hours for its prey to
come within reach, then it uses all of its four to five meters of muscular
coils to constrict and suffocate a variety of prey from antelope to
squirrels.
And one such morsel comes into range, an adventurous young squirrel at an
age ready to wander away from its mother, but she keeps an attentive
vigil from above.
The slightest ripple on the water's surface and she sounds the alarm.
The young explorer rushes to safety.
The warning came just in time.
The young squirrel managed to escape becoming a snack for the python.
But the python can easily go without food for several weeks.
The mother squirrel holds the youngster down for a forced grooming,
a minor punishment considering what it just escaped.
Below them, the silent Limpopo's stalker visits the water's edge before
she begins to hunt.
The leopard is the largest spotted cat in Africa and the biggest of the
solitary hunters.
Her territory stretches along the riverbank, a thoughtful choice
considering that her prey is attracted to the only source of water for
kilometers.
Stealth and patience are the leopard's strongest attributes.
They enable her to sneak up on her prey unnoticed.
Her target for tonight, a scrub hare.
Normally, she would devour a small prey such as this, but tonight the
leopard does not eat her kill.
She has a dependent to feed, a male cub waiting in a tree for his dinner.
She delivers the hare intact.
At 10 months, he's bigger than his mother and almost fully grown, but he
still depends on her for food.
However, she won't provide his meals for much longer.
Soon she will be ready to mate again, and she will force him out of her
care, then he'll have to catch his own food.
And in preparation for his bachelorhood, he trains on prey that
is already dead.
His mother makes herself comfortable, while the cub expends some energy.
This exercise helps him learn how to catch his own meals, how to pounce on
and grip his prey.
But there is only so much that he can learn with such a small prey item, so
he settles down to eat.
As the Limpopo attracts the leopard's food to its banks, it also traps prey
in its waters.
The dwindling river leaves behind isolated pools, which imprison the
water inhabitants.
Easy prey for opportunistic hunters.
The civet usually forages silently near the river for insects and wild
fruits.
The trapped fish can't hide and the civet is not a selective eater.
It spots a chance for a change in menu.
The dry season provides great opportunity for cunning predators such
as civets and leopards.
By the time her cub has finished his meal, the female leopard patrols her
riverfront territory.
She checks regularly to ensure that no one invaded her turf.
Leopards are generally silent, solitary creatures unless a female has
cubs and calls to bring them out of hiding.
Now she summons her large cub even though he makes a complete nuisance of
himself.
For the moment she tolerates him.
By the time the rains come, he'll be old enough to leave her and will have
to make his way alone.
But the change of season is not far away, a storm brews upstream.
Several weeks after the first rain, raging waters surge down the Limpopo,
a roaring flood fills its course to capacity.
A powerful mass of water uprooting whatever stands in its way.
Now the Limpopo becomes a true giant, up to a kilometer wide.
The inhabitants of the Limpopo enjoy this time of plenty.
The abundance of food and water allows the animals to disperse over the wide
plains of the Tuli Block.
The elephant herds move into the scrubland where the new growth
satisfies their monstrous appetite.
The youngster tries to tame his trunk that seems to have a will of its own.
And once again water fills their favorite water holes.
Although the slippery banks get the smaller ones into trouble, the rest of
the herd rushes to help.
This time, it was only a lesson in pride.
The new season finds the young male leopard on his own, and an
accomplished hunter.
For now he is a nomad, but in a year or two he will set up his own
territory along the river.
Then he will earn his place among the formidable group of animals of the
Limpopo.
The second river, the Sand in South Africa, flows through a rich
wilderness called the bush-felt.
This is the land of the notorious big five, two of which form impressive
herds, the elephants and the buffaloes.
But the Sand is also home to a feathered giant, the largest raptor in
Africa, the Martial Eagle.
The long awaited summer rains reach the bush-felt.
The Sand river swells quickly.
Within a few days, the river is in full flood.
Now it earns its traditional African name, Moyatla Mukhaley, which means
fierce when in flood.
So fierce that it sweeps away the vegetation in its path.
The flood only lasts a few days, and the elephants make the most of it.
For them, this is a time of pleasure, a brief period of the year when they
can submerge their entire body.
Bathing is a social event and a time when males of different ages learn
their strength and status by mock fighting and playing.
The thunderstorm season is short lived.
Soon, the river shrinks back to its winter course exposing the sandbanks
that give it its name.
Like the Limpopo, the Sand river is a magnet for the inhabitants of the
surrounding land.
The Martial eagle uses a shallow stream to clean off its plumage and
get rid of some unwanted feather lice.
But the eagle's bath is about to be disturbed by another of the Sand's
giants.
The stampeding buffaloes frighten the bird away.
Buffaloes never venture far from the river.
They need the water to help control their body heat.
They also enjoy a meal of reeds, while they wallow and drink.
After a few hours, the refreshed buffaloes leave the river to continue
feeding in the grass plains of the bush-felt, a little corner of Africa
where the Sand river supports some of the largest remaining herds of
Africa's giants.
But not all rivers provide such abundance for their resident
elephants.
In the heart of the Namib Desert, the Hoanib River is the third and the most
unusual of the continent's rivers.
It moves through one of the earth's harshest environments, a dry
wilderness of scorching sun and barren rocks.
For most of the year, the river runs underground, occasionally breaking the
surface along its course in a few springs and small oases.
It only flows freely above ground for a few days a year.
The river passes through an unforgiving environment, but offers
little food or water.
But two of Africa's largest mammals manage to survive here, giraffes and
desert elephants.
Small herds trek over the scorching sand to find food and water.
They have become perfectly adapted to their parched circumstances, and have
learned to make the most of what little vegetation is offered by the
desert.
Unlike their savannah cousins, they are careful not to destroy the trees
they eat, picking only what they need.
Nothing goes to waste here, dry seeds and hidden roots provide food for the
few inhabitants that have made this their home.
As a rule, elephants prefer to drink every day but to survive in this
wasteland, these herds have adapted to go without water for up to four days.
These are the most remarkable elephants in Africa, able to sense
water from kilometers away even in places where it lies hidden beneath
the sand.
These few places occur where the river rises close enough to the surface for
the elephants to reach.
After a little digging, the hidden waters seep to the surface.
These extraordinary animals can travel up to 70 kilometers to find water.
They never stay in one place for long.
Needing to search for more food, they continue their endless wandering up
and down the Hoanib's hidden river course.
During the most desperate time of the year, the elephants know all of
nature's tricks.
October, the time when the largest tree in the riverbed, the Ana tree
sprouts new leaves and seeds.
Many of the animals and birds of the desert depend on this tree for food
and shelter.
Its extensive root system taps water and nutrients from the hidden river
below, and produces young leaves which the tallest animals pluck and eat.
Only the giants of the Hoanib can reach so high, but they feed on more
of the tree than just the leaves.
The most nutritious part of the Ana tree is its pods.
It is unbelievable that the nutrients stored in these seeds are rich enough
in proteins to sustain the largest mammal on land.
During this time when all the other plants bear no leaves or seeds, the
elephants rely on the Ana tree for food, but the tree relies on the
elephants too.
Ana seeds can only develop after they have passed through an elephant's
digestive system.
Its stomach juices dissolve the hard outer layer of the seeds.
They germinate, take root, and are fertilized by the elephant's
droppings.
It's amazing how in this dry wilderness where living is a daily
struggle, two giants depend on each other.
Survival here is determined by the animals' ability to adapt to the
severe conditions.
The giraffe is another well adjusted giant of the Namib desert.
It too can live without water for remarkable lengths of time, even
longer than the desert elephant.
The strong, hot winds add to the animals' discomfort, but they may be
carriers of rain.
High above the dust storm, the moisture finally gathers into clouds.
The never ending drought is broken at last.
The long awaited rain rejuvenates the parched land.
In the surrounding mountains, the water gathers into streams.
Suddenly, there is a river were so recently there was only sand.
In just a few hours, the dry riverbed is transformed into a raging torrent.
It brings fertile soils from the mountain slopes to the valley.
However, this transformation is short-lived.
Within days, the Hoanib River soaks back through the sand and returns to
its underground course.
Soon, all that remains are a few shallow pools and quickly drying mud,
a rare treat for the elephants.
After months of struggling to find food and water, the elephants can now
afford to play.
For this youngster, born in the driest time of the year, the rains came only
just in time.
There is enough food and water here for it to grow strong and keep up with
the herd's wanderings.
In the aftermath of the flash flood, the riverbed comes to life.
For a very short time, the living is easy for the giants of the Hoanib, the
Namib desert's hidden river.
The fourth river is Tanzania's Rufiji.
It boasts a more hospitable flood plain for its quota of large
inhabitants.
Elephants and hippos revel in the abundance of water all year round.
Porcupines, the largest rodents of Africa forage at night.
And giraffes browse from the tallest trees.
Even during the dry season, this perennial river flows strongly.
However, the herbivores' food is not so abundant.
The hippos have to leave the water for long periods to graze from the sparse
vegetation.
But this exposes their sensitive skins to the harsh African sun.
To prevent sunburn, their skin secretes a reddish fluid tinting the
whole body slightly pink.
Adapting to a changing environment is crucial for a giant's survival.
Like its desert cousin, the elephant here has developed different skills to
find food, although it is very destructive in its approach to get to
the unreachable fruit of the doum palm.
Basically, the elephant's secret to survival in Africa's varying
conditions is its ability to feed on anything that nature offers.
But these giants have an appetite to match their size.
They have a poor digestive system, so they need to consume huge quantities
of food.
Only 40 % of it gets digested.
So feeding takes up to 16 hours of the elephant's day.
A day, which is quickly coming to an end.
Darkness reveals some shy and secretive creatures.
Porcupines are mainly active at night.
Although they are known to be very cautious creatures, they are
exceptionally noisy eaters.
And even though they walk about on padded paws, their eccentric armor
rustles up quite a noise.
The long, sharp quills are an essential defense mechanism against
predators such as large cats.
They are also incredibly adaptable animals which cope well in changing
environments and climates.
To keep a comfortable temperature all year round, they can increase their
heat loss in summer and produce more heat in winter.
Giraffes find food where no other large animals can find enough to
sustain their bulk.
They browse on the tallest branches for new tender shoots.
But not all vegetation simply allows itself to be eaten.
The whistling thorn has a symbiotic relationship with the cocktail ants
that protect it from herbivores.
The ants make their home in the thorns of the tree and viciously protect them
from any animal that might try to eat their abode.
But giraffes learn the ants' defense ploy, and know better than to try the
whistling thorn.
Instead, this one chooses a different tree.
Here, the animals' lives depend on their ability to find food where there
appears to be none.
But at the Rufiji, the river constantly provides one of the
precious essentials, water.
The fifth river of giants is South Africa's Pongola, a river that feeds
several wide pans on its way towards the ocean.
These tranquil lakes provide the winter home of the Pongola's giant
reptiles, the crocodiles and the resident pods of hippos.
The pans form a haven for them, shallow standing water deep enough to
submerge and plenty of grass growing on the surrounding flood plains to
eat.
The pans are linked to the river by smaller channels.
By the end of summer, the channels are low and a man made cement path built
in one of the channels becomes a hub of activity.
Red breasted tilapia swim upstream to get to their breeding grounds.
But the small waterfall formed by the causeway makes a huge hurdle in the
path of the small fish.
Driven by instinct, they fight the gushing water.
But their struggles attract the attention of keen predators.
Below the waterfall, the crocodiles wait in patient ambush.
This extraordinary adaptation shows the crocodiles' ability to adjust to
changing conditions.
In this case, they make the most of a feast which only occurs for a few
weeks of the year.
To
swallow its catch, the crocodile tenderizes the fish and gets it into
position to gulp down in one mouthful.
The waterfall and its crocodiles are only the first obstacle for the fish.
Once they make it onto the concrete path, they must dodge the beaks of the
fishing team.
The surviving tilapias put on their full breeding colors.
The male's belly is tinged with crimson shades beautified to
perfection to attract the attention of a mate.
The tilapia's breeding season heralds the end of summer.
After spending the warm months in the Pongola river, the crocodiles return
to the pans to endure the winter chill.
They need to do all they can to keep their body temperature above 18
degrees Celsius, otherwise they go into a dormant state.
Through winter, the pans remain at a constant temperature and at night, the
water remains a few degrees warmer than the air.
So the crocodiles retire to the bottom.
They stay underwater for more than an hour at a time by slowing the heart
rate to about four beats a minute.
During the cold months, temperature regulation becomes a vital survival
skill for a reptile that usually inhabits the warmer, tropical parts of
Africa.
The lower winter temperatures make the crocodiles slow and lethargic, until
the sun's rays warm their bodies.
A Goliath heron takes no notice of the sluggish reptile.
This giant of the heron family stands one and a half meters tall, and seeks
out appropriately large size prey: fish, lizards and snakes.
But sometimes, other things appear to be food.
The heron scrapes its beak clean, before using it to preen its feathers.
By now, the sun is strong enough to enliven the Pongola's cold blooded
giants.
A morning treat for a warm-blooded one, too.
Towards the end of winter, the pans of the Pongola start to dry up.
Deep areas are few, and the hippos herd closer together.
Now they are forced to share the remaining space with the new arrivals,
migrating white pelicans.
The pelicans eagerly catch the fish that gather around the hippos to feed
on their droppings.
But the hippos make bad social companions.
Irritated by the crowd, they clear some space.
The feeding session comes to an end and the pelicans are forced off the
water.
A few months later, the warmer days of spring bring the crocodiles out of
their winter lethargy.
Energized by the new warmth, they leave the pans and return to the
Pongola river.
Now the males look for suitable areas to set up their territories.
Each one includes a part of the bank and the water space in front.
Trespassing males are not welcome.
The intruder is banished and the dominant male begins the ancient
courtship ritual of crocodiles, an elaborate display of jaw clapping and
bubble blowing.
Females freely roam through the territories and choose the best suited
or best displaying male.
Once she's found her type, she encourages him to mate with her by
rubbing her chin on his head.
She's not the only one to ask his favors, he's going to be a busy male
for the next few days.
Soon, the females will lay the clutches of a new generation of
Pongolas giant reptiles.
But this is a breeding cycle that occurs along other rivers of Africa,
including the Victoria Nile in Uganda, a sixth river and the beginning of the
longest river on earth.
The birthplace of the Nile is home to some of the oldest giants in Africa:
hippos, elephants and crocodiles.
This December sunset over the Nile triggers the next phase of the
crocodile's life cycle.
The pregnant female chooses a suitable site on the riverbank to dig her nest
well above the waterline.
While laying, she slips into a trance and deposits up to 80 eggs.
Then she wakes up and covers her clutch methodically.
She compacts the earth over the eggs to squeeze out any air pockets that
could cause them to rot.
After almost two hours, her hard work is done.
Dawn reveals that she was not the only one to make a nest here.
Many crocodile mothers lie possessively over their developing
eggs.
They share their nesting site with unlikely neighbors.
Although this might seem a precarious place for such a little bird to nest,
there is method in the dikkop's apparent madness, living with
crocodiles, affords added protection.
Nevertheless, while one dikkop parent broods the eggs, the other keeps an
eye out for scavengers.
Monitors are renowned egg thieves, the sworn enemy of every crocodile nesting
site.
Unfortunately, the dikkops wreck the monitor's plan to find an unguarded
nest.
The lizard moves away and towards another nest well guarded by a pair of
equally hostile dikkops.
The brave little bird spreads his wings to make himself appear larger to
intimidate the monitor and distract it from finding the nest.
The ploy works and the monitor gives up its search.
The dikkop's alarm calls alert the crocodile mothers that left their
nests briefly to cool off.
In a hurry to get back to her own clutch, this mother steps dangerously
close to the dikkop's nest, and the little bird voices her distress, but
there's nothing she can do against the crushing force of such a giant foot.
A narrow escape.
Nevertheless, this site is worth its risks.
Now that the crocodile mothers are back, no monitor will come close.
Here, even hippos run the risk of being crushed to death by a power
source larger than themselves, the Murchison Falls.
The turbulent rapids that precede the waterfalls seem a dangerous place to
choose as a home.
This family group has braved the force of the white waters for generations.
Although the adults are strong enough to fight the wild currents only a few
hundred meters away from the falls, their youngsters or not.
It's a mystery how any babies ever make it to adulthood.
This four year old male made the fatal mistake of climbing on to the opposite
bank.
Here, the sheer cliffs are too high for it to escape to safer ground.
Its life is in danger and its mother cannot help.
The only way off the bank is to get back into the water.
But the rapids overpower the small hippo.
The churning waters quickly pull it down.
Then unbelievably, the exhausted youngster finds a foothold on the
slippery rocks and climbs safely back onto land.
But to reach its mother and the rest of the family, it will need to brave
the deadly rapids once more.
The youngster tries again.
Inevitably, the power of the river proves too strong for the
inexperienced hippo.
He disappears in to the mighty falls.
Most of the Nile's headwaters are channeled into one gorge only eight
meters wide.
No creature could survive these falls.
Too young to conquer the strength of the Nile, this hippo meets an untimely
death.
The strength of the plunging water is so enormous that it creates foam for
hundreds of meters downstream.
The hippos living in this foam bath have made a much safer choice than
their relatives in the rapids above.
Further downstream, the waters of the Nile calm into a steady flow and widen
around reed covered islands.
These areas are used by shoebills, the Victoria Nile's only endemic bird
species.
It also has no known close relatives, living or fossil.
It's a giant aquatic bird that does not swim or dive for its food.
It hunts by using its binocular vision to look for prey.
Once it locks its sight on something, it literally collapses onto it.
This one and a half meter tall bird is very rare, and there are only about a
thousand shoebills in Uganda.
Africa's wilderness areas are shrinking, and its giants are joining
the long list of rare and protected species.
The elephants are no exception.
With the surrounding land used by man, the elephants of the Victoria Nile
wade through the river to get to the reeds on the islands.
The elephants' matriarch negotiates the waters of the river first.
She clears the way of possible danger.
A bad tempered territorial hippo could pose a threat to the younger calves.
Once the way is open, the rest follow.
Bringing up the rear is a youngster who lost her trunk in a poacher's
snare.
An elephant without a trunk is like a fish out of water, yet her survival
demonstrates the strong bonds between the members of an elephant herd.
She adapted remarkably well to her situation, but she wouldn't have
survived if the herd hadn't changed its lifestyle.
Now they only feed on the island where the trunkless female can use her mouth
to eat the tall, soft reeds.
An elephant's trunk is highly specialized.
Thousands of muscles are coordinated to act out each chore.
Without it, an elephant needs to learn a whole new way of feeding, drinking
and interacting with the world.
A world in which even the largest land mammals need to tread carefully to
survive.
And where giant reptiles need to battle the odds to raise their young.
For the past three months, crocodile mothers have faithfully protected
their eggs from scavengers.
They briefly left their nests to drink and cool off in the river, but not to
eat.
On her return to her nest, this mother starts to dig guided by the faint
cries that she hears from beneath the sand.
She gently uncovers the first hatchlings, and their cries stimulate
the others to follow.
Unique in the reptilian world, this species has a nurturing side not seen
in other reptiles.
Guided by her maternal instinct, the mother gently gathers her young in the
same jaws that mean death to so many others.
With her gular pouch filled with wriggling bodies, she makes her way to
the water.
She releases them in a safe place among the grasses and reeds that line
the river's banks.
Her maternal duties will end soon, but for the next few weeks, she will stay
in these quiet backwaters to protect her hatchlings from larger crocodiles
and other predators.
The babies are born hunters, they catch their first meal only a few
hours after hatching.
Miniature copies of the next generation of a lineage of reptiles
that in ancient times ruled the entire course of the Nile.
As well as the waterways of West Africa where the seventh river the
Ogooue harbors the exceptions to the rule of river giants.
The Ogooue traverses Gabon's topical valleys and mountains, a rich
environment which is home to smaller versions of their massive savannah
cousins, the forest elephant, the forest buffalo, and two species of
crocodile: dwarf and slender snouted.
Crocodiles that occur in the brackish water of the mangroves in the delta.
With its elongated snout, an adult reaches a length of three meters, but
that is still only half of the average length of a Nile crocodile.
And the dwarf crocodile is even smaller than that, reaching only two
meters.
Its hatchlings are so small that even ants irritate their sensitive skin.
The river provides a good refuge for this water dependent creature.
However, not all the animals here rely so much on the river.
The tropics offer abundant water in pools for the forest buffaloes.
Their light build and small herds prevent overgrazing of the limited
areas of grasslands.
But they have some typical buffalo behavior.
They enjoy a good wallow.
The African elephant's forest cousin is almost half its size, weighing
about 1,000 kilograms less.
Its stature and small tusks allow it to move easily through the
impenetrable forest.
A hidden world where the sunlight filters to the forest floor carpeted
with fallen leaves, the perfect warm conditions for a forest cobra's nest.
If this hatchling survives to adulthood, it will become one of the
largest African cobras and the only true giant of the Ogooue River, the
last of the seven massive rivers that provide refuge for Africa's greatest
beasts.
A company of powerful and impressive titans.
From the largest land mammal to the biggest reptile in Africa.
All of them undisputed river giants.