Original subtitles

Narrator: Africa's most iconic landscape: Savanna.

A stage where nature's greatest dramas unfold.

Famous for the "big five,"

It's also home to less well-known creatures.

From predator to prey,

Energy flows through this dynamic system.

Every species has a role to play

In the savanna's unique web of life.

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Africa is dominated by thorn bush savanna,

Vast, sweeping grasslands that cover almost half

Of the continent's surface.

Savanna covers over 12 million square miles,

Stretching across 27 african countries, and beyond.

Twenty percent of the planet's surface

Is dominated by grasslands.

Surprisingly, the plant at the heart

Of the savanna's story is a humble grass.

South african savanna contains a rich diversity

Of grass species...

Countless slender stems that feed an entire ecosystem.

The savanna is a complex web of life, from the plants

At the bottom of the food chain, to the predators at the top.

Stories of life and death

Have unfolded on these plains for millions of years.

Grassland provides a feast for herds of grazers...

And the carnivores that track them down.

Lions are the savanna's definitive hunter.

The impala instinctively runs for cover.

But lions are masters of ambush.

The lionesses' hunting partner greets her;

This is a shared success.

Most hunts end in failure.

This kill is good news for their pride.

This meal will feed the family, including their growing cubs,

Curbing their hunger for several days.

It is through these fatal dramas

That energy flows through the savanna's

Dynamic food chain.

Plants eaten by the herbivores

Ultimately also sustain the carnivores.

The word "savanna" conjures images of open, grassy plains

Devoid of trees--

Such as those of tanzania's famous serengeti.

But these are not typical.

Most savannas have many trees,

Growing in delicate balance with the grasses.

The key to the existence of savanna is light.

Its trees must be widely spread,

So the canopy can't close over and shade out the grasses.

The other essential ingredients

Are warm temperatures year-round,

Peaking in a hot season...

Complete with summer rains.

During this wet season, a precise amount of water--

More than 20 inches -- must fall for the grasses to thrive.

Last but not least the savanna depends on its animals,

Whose grazing habits encourage new shoots.

Harnessing the sun's energy is the first step in a cycle

That ultimately feeds all the hungry mouths in this ecosystem.

But the savanna is not only somewhere to eat.

It's also a refuge,

Providing shelter for animals.

Of all its creatures, none are more important

To the landscape than elephants.

Their feeding habits maintain these open grassy plains,

Which would otherwise revert to forest.

Elephants live in stable groups of closely related females

Led by a matriarch.

She has an intimate knowledge of the landscape and,

In particular, the best feeding places.

It's no surprise that elephants have enormous appetites.

Bush elephants are the largest of all terrestrial animals,

An adult female weighing in at over three tons.

It takes five percent of her body weight--

Around 150 kilograms of vegetation per day--

To fuel a body this big.

Every day, elephants spend up to 16 hours

Consuming everything from grasses to bushes,

Even whole trees.

The herd leaves a trail of destruction behind.

Or so it seems.

In fact, their bulldozing activity

Is essential to the savanna.

By felling a proportion of the trees in any one area,

They reduce the shady canopy;

Enabling light to reach the understory,

So grasses have a chance to grow.

The fallen branches also protect these new shoots,

Preventing grazers reaching them.

Elephant activity renews the grasses and, surprisingly,

The damaged trees also benefit.

Resilient species such as acacia have adapted to cope

With their brutal pruning by re-sprouting.

The acacia also relies on them to help plant its seeds.

Elephants have inefficient digestion,

So many of the seeds they consume

Pass through their gut undamaged.

The dung is so rich in minerals it provides the perfect compost

For the acacia seeds to germinate.

The nutrients also support other life forms.

Dung beetles eat it,

And roll dung balls over large distances to use as nests,

Fully stocked with food for their larvae.

These busy beetles help to fertilize the surrounding soils

And spread the seeds, which take root in new areas.

So the plants eaten by elephants are also fed by their dung...

And the interconnected cycle of life continues.

Once her family is full,

The matriarch leads them on to new feeding areas.

Elephants play a central role

In the renewal of the landscape,

Making homes for a diverse community of wildlife.

Africa has the world's greatest concentration of antelope,

Most of which live on the savanna.

Blue wildebeest gather in large herds,

Consuming grasses rich in phosphorous and nitrogen.

Once the grasses are exhausted,

The wildebeest will be forced to move on,

Often joining mass migrations in search of fresh pastures.

Wildebeest herd together for protection against predators,

Frequently associating with other grazers such as zebra.

Remarkably there is little competition

For food between species,

Because they have distinct feeding habits.

Most of the year there's plenty to go around,

But the landscape is changing.

It's the end of the dry season, a tense time on the savanna.

After months without rain,

The tender grasses have been cropped to ground level,

Nibbled by an army of hungry grazers.

This hasn't killed them.

If the rains come they will re-sprout.

But now only the old indigestible vegetation remains.

At this time of year grazers struggle to find enough to eat.

Surprisingly, even in times of shortage,

There's little conflict over food.

The secret to life on the savanna is sharing.

But competition is fierce for another reason.

This is the start of the breeding season.

The animals are sizing each other up as potential mates,

Or rivals.

The predators are here to pick off the weaker individuals...

And the scavengers to pick up the pieces.

Lions are always on the lookout for their next meal.

They live in groups, called prides,

Consisting of closely related females

And the area's dominant males.

Lions may be deadly predators, but they actually spend

Most of their lives sleeping...

Up to 20 hours a day.

This pride is mainly active at night

When their nocturnal vision gives them greater advantage

Over their prey.

The reflective strip under the eye helps lions

To see better in low light.

For now, though, they do as little as possible.

Thanks to the cool shade of the tree,

The family can relax.

But the peace won't last.

There is fierce competition amongst carnivores

On the savanna...

They all eat meat, which is challenging to kill.

Within the pride, it's the lionesses

That are the main hunters.

Even with their combined power, a kill is not guaranteed.

With the pride taking every chance to hunt,

The savanna community must watch its back.

Adult rhino though, have little to fear.

Like many savanna grazers, they're grass specialists.

They lack incisors, relying instead

On their strong flat lips to hoover up short grass,

Chewing it between massive molars.

White rhino are the world's largest species,

Like this bull, weighing in at around 4,800 pounds.

This female is accompanied by her youngster,

Around six months old.

But with the bull nearby, they're heading towards danger.

Mothers with young normally steer clear.

Bulls are known to attack other rhinos

That get between them and a potential mate.

Even the very young.

But, unusually, the mother allows her calf

To approach this large bull.

He could easily kill the youngster

With one stab of his lethal horn.

But the bull's reaction is surprising.

He seems to welcome the youngster's attention

And responds gently, even playfully.

Bulls spend most of their lives alone,

But do occasionally tolerate other submissive males

In their territory.

After his risky adventure, the little calf returns

To the safety of his mother.

She is key to his survival on the savanna,

Protecting him for his first two vulnerable years of life.

Although she's started to wean him,

The calf will rely on his mother's milk

Until he is a year old.

Adult rhino have no natural predators

Because they are large, thick-skinned and well armed.

However, calves do occasionally fall victim to lions.

Rhinos have poor vision,

Relying instead on their excellent hearing

And sense of smell to detect threats at a distance.

The mother can't see the lion clearly.

But she can smell him.

With her precious calf an easy target,

She's not taking any chances.

Rhino can charge at speeds up to 25 miles an hour,

A lethal battering ram.

The female is more than a match, even for a big male lion.

At last the calf's back with his mother,

Where he can suckle in safety,

Thanks to her devoted protection.

One of the lions' favorite prey is buffalo.

The young ones are an easy target.

Even adults regularly fall victim.

To protect themselves, buffalo find safety in numbers,

Living in large herds:

Complex, ever-changing societies of males and females.

As a strong, united front, these herds can fight off an attack

From a whole pride of lions.

But the herds are also targeted by smaller creatures

With a taste for their blood.

Plagues of parasites feast on their skin.

Horns are useless against this onslaught of biting insects.

But buffalo have a strategy.

Close co-operation with red-billed oxpeckers.

These helpful birds pick off fleas, ticks and swarming flies.

Buffalo trust them to remove the tormenting insects

And the oxpeckers benefit from a constant supply

Of nourishing food.

And wherever the herd goes, the oxpeckers go too.

Communal living has advantages, but also creates a problem.

For buffalo, life in the herd means many mouths to feed.

So they can't be too fussy about what they eat.

Their savanna staple is grass,

But there are some treats on the buffalo's menu too.

Being large animals, they can reach high

Into the savanna's bushes.

Another savanna specialist is the world's largest antelope,

The eland.

Large males are almost as tall as a man,

Over five feet at the shoulder,

But are up to ten times as heavy.

Like buffalo, eland eat a combination of grass and leaves.

They adapt their diet

According to what is available.

Eland have the peculiar characteristic

Of clicking as they walk.

It signals dominance--

The larger the bull, the deeper the clicking sound.

Smaller and more elusive is another

Of the savanna's antelope, perhaps the most elegant of all:

Kudu.

Secretive creatures, they are rarely seen out in the open.

Targeted by many savanna predators,

Kudu have camouflaged, striped coats that blend

Into the background so they can hide in the thickets.

Like all ruminant animals,

This female must chew the cud.

Every mouthful is chewed, swallowed, regurgitated--

And chewed a little more.

Bacteria from the animal's stomach helps to break down

The cellulose in the leaves as it is processed

For a second time.

Like the kudu, in its leafy hideaway,

All the savanna's animals ultimately owe their existence

To the variety of habitats in this unique landscape.

The savanna is one of the world's richest biomes--

Boasting exceptional plant diversity--

In some areas over 5,000 plant species.

A variety of savanna trees grace the landscape,

Including the resilient acacia.

This definitive savanna species is not only eaten by elephant,

It's the favorite food of another iconic character,

The world's tallest animal: Giraffe.

Their extreme height, with males standing over sixteen feet tall,

Enables them to graze the treetops.

Long legs give giraffe an unusual way of walking.

To avoid tripping up over their dinner-plate-sized hoofs,

Both legs on each side move simultaneously.

And although acceleration is slow,

Their top speed of over 30 miles per hour

Enables them to outrun lions.

Their stature not only provides a vantage point

When it comes to predators, but also gives access

To the sweetest new leaves in the canopy.

This means that they don't have to compete for food

With shorter animals.

And it's not just their long necks

That give them the advantage...

They also have a prehensile, 18 inch tongue

Which extends their grasp.

Thorns, the acacia trees' usual defense, don't deter them.

But the trees are not completely at the giraffe's mercy.

The acacia does fight back in a surprising way.

As soon as a tree is eaten by browsers

Its leaves produce poisonous tannins.

They also emit a chemical, ethylene,

Into the air that can disperse over 130 feet.

Incredibly, scientists have discovered the acacia

Are one step ahead of the giraffe.

The chemicals released by a damaged tree

Are detected by its neighbors,

That rapidly activate their own chemical defenses.

Within a few minutes all the trees in the area are toxic.

It's an extraordinary early-warning system,

Evolved to protect plants from hungry animals.

But plant poisons aren't enough to deter

The most destructive grazers of all.

The matriarch and her family

Are tucking into another stand of trees.

Elephants can tolerate high levels of tannin in their food,

As well as latex and even hydrogen cyanide.

This is only possible because they vary their diet seasonally,

Switching to grasses after the rains.

Every animal is adapted to their place

In the savanna's food chain.

This is nature's own recycling system...

Where destruction ultimately promotes new life.

At the end of the dry season,

Testosterone is flowing.

In preparation for mating,

Wildebeest carve up the landscape into territories.

The rut has begun.

Each male is fighting to defend his tiny patch of turf.

If he can hold his ground and guard his females,

He will get the chance to mate.

In the buffalo herds, males are vying for position too.

Both sexes have horns, but only the males

Grow heavyweight headgear,

Forming what is known as a "boss."

This acts both as a weapon and as protection

During head-to-head combat.

It can take eight years for a bull

To win breeding females and father offspring.

The zebra stallions are fired up too.

A male can only control his harem of females

If he can successfully fight off the competition.

The challenger will steal his harem if he can win this battle.

With so much to lose, the stallion's not backing down.

But violence doesn't always pay.

Despite their size and sharp horns,

Eland are peaceful creatures.

Male dominance is not decided by sparring,

But according to a strict social pecking order.

Subtle features, such as size of the dewlap,

The thick skin fold under the neck,

To the size of their horns,

Determines who gets access to females.

But keeping the peace is the exception to the rule

At this time of year.

Mature bull giraffes are generally solitary,

But to gain mating rights to females,

They come face to face to establish dominance.

The only way to decide who's boss is a "necking" contest.

Aiming at the legs they each try to destabilize their opponent.

A male's head is like a 60 pound wrecking ball

At the end of a long, strong, flexible neck.

Short, bony horns can cut and bruise.

Giraffe fights can last for half an hour

And injuries sustained can be devastating.

Jaws and necks are sometimes broken.

But fights rarely prove fatal.

But in this instance, there is a clear winner.

Head now held high, he's secured himself

The best chance of attracting a mate and passing on

His winning genes to the next generation.

His next challenge is to win over a female.

Giraffe bulls darken in color as they mature.

This one's in the prime of his life

And he's found a potential mate.

The flick of her tail indicates she is receptive,

So he now has a good chance of mating.

It's no coincidence that most of the savanna community

Breeds at the same time.

For many species, the birth of the new generation

Coincides with the rainy season.

The coming rains will flush the savanna with fresh new grasses,

Vital if there is going to be enough food

For the hungry new babies.

Predators are able to breed year round,

Enabling them to raise their young during times of plenty.

Birth rates amongst lions peak when there are lots

Of vulnerable young prey to catch.

This dominant male has already secured his mating rights

To a pride of females,

Through fierce battles with other males.

He warns the competition to keep out by scent marking.

He's been tracking a receptive female for days.

(lion grunting)

The pair have isolated themselves from the rest

Of the pride for the last 48 hours.

And they've started to mate, regularly once every 15 minutes.

Lions mate quickly and often, up to 40 times per day

And long into the night,

To maximize the chance of fertilization.

Eventually the female returns to the pride.

If she is now pregnant, in three months she will give birth.

Many of the lionesses already have cubs

And feeding their demanding youngsters is thirsty work.

Within a pride females often synchronize their breeding,

Sharing the childcare and even the suckling duties.

Cubs of a similar age are also more likely to survive,

Because being the same size they have equal access to food.

At 11 months old,

Cubs are allowed to join the adults

When they go out hunting; until then, they have to stay behind

Under the watchful eye of a babysitting lioness.

The breeding season is a drain on energy for all species,

Particularly at the end of the dry season

When food quality is poor.

Over recent months the elephants have been traveling

Through a steadily drying landscape.

At this time of year 70 percent of their diet consists

Of trees and bushes.

But elephants also eat fresh grasses,

And these can't grow without water.

Everything now is waiting for the rains.

The matriarch sniffs the air.

Elephants have an excellent sense of smell.

They also have acute hearing,

Sensitive to low frequency sounds,

Such as distant thunder,

And are believed to be able to detect coming rains,

Hundreds of kilometers away.

(rumbling)

Rain...

The essential ingredient for the renewal of the savanna.

Within days,

The first green shoots sprout from moistened ground.

Fresh food for a growing savanna community.

And there are new faces everywhere.

Out on an open plain, female blesbok antelope

Are beginning to drop their lambs.

From its high vantage point,

A verreaux's eagle has spotted the activity.

An adult is far too big to be targeted by the raptor,

But newborns are vulnerable.

The eagle's found the next best thing,

A discarded afterbirth.

It makes a perfect meal.

Verreaux's eagles mate for life, and its partner is hungry too.

Eagles are efficient hunters,

But they will scavenge if the opportunity arises.

Thus becoming a vital link in the savanna food chain,

Recycling the nutrients back into the system.

There are new additions to the resident lion pride.

One of the females has returned with her six-week-old cubs.

Isolated with their mother in the safety

Of a birthing den until now,

They're ready to join their extended family.

For the female cubs that will remain in the pride for life,

This is the start of a long cooperative relationship.

Born at this time of year, there should be plenty of food

For the growing family.

And, with the cubs close in age, they'll be equally matched

When it comes to seizing their share.

In time their mothers will teach the youngsters how to hunt

And take their place as apex predators.

For now, though, their carefree days are full of play.

The rainy season has brought water in volumes

And the waterholes are full.

Elephants love to get wet.

The matriarch and her family indulge in a deep bath.

Elephants are experts at finding drinking water,

Even during drought, but it's a treat to find water

Deep enough to plunge into.

Bathing is part of an elephant's cleaning routine,

Which also involves scratching against trees

To slough off loose skin and parasites.

The whole family joins in.

The savanna lies at the heart of untamed africa...

Where the fortunes of animals and plants are interlinked

In a eternal cycle which brings renewal and fresh growth.

Now flushed green,

The landscape will nourish its animals for months to come...

Creating energy to feed the savanna's dynamic web of life.

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