Original subtitles

The wilds of southern africa teem with life.

While most consider big cats

Or huge tuskers

As the true wild icons of africa;

Few appreciate the smaller creatures

That dominate the land

The antelope.

They too have rich stories

Filled with the daily struggle to survive.

An intricate array of trials and tribulations,

Centered on the need to feed and breed.

With stories no less compelling,

They're rarely told.

Of these, two antelope outnumber all others -

Springbok

And impala.

For both, life in the herd

Is critical to their success.

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The long lazy days of summer in southern africa

Are coming to an end.

While conditions are cooling down however,

Relationships in the bush are heating up.

It's the rut -

Mating season for impala.

At this time of the year,

Males fight each other for mates.

Between fighting off rivals and chasing down females,

Life is tough.

There's little time for eating

And males quickly lose condition.

This is the toughest time of the year and the most important,

Because only the winners will go on to mate.

The plains of southern africa teem with antelope.

There are more species here than on any other continent.

These range in size from tiny duikers and steenbok

Weighing about as much as a domestic cat

To massive eland

That are the size and weight of a large cow.

From forests to deserts,

Antelope are the backbone of the environment.

But no matter whether they're big or small,

All species are herbivores

And therefore are closely tied

To the prevailing environmental conditions.

Fed by moist winds blowing in across the warm indian ocean,

The east receives lots of rain -

Almost 40 inches a year -

And is covered in thick lush vegetation.

Meanwhile, the western parts are drier

Receiving less than 20 inches of rain a year

And semi-desert environments dominate the landscape.

Water is scarce

And food is often limited and difficult to find.

Droughts here are regular and severe.

Temperatures regularly soar over a hundred degrees.

And every plant and animal living here is specially adapted

To overcome the rigors imposed by the conditions.

Meanwhile the eastern parts of the region are more congenial;

Moist savannas pulsating with life dominate.

It's more humid and not overly hot

With temperatures hovering pleasantly in the mid eighties

Year round.

The vegetation is lush and green.

More often than not

There is plenty of food to go around.

Across this continental divide

Two species of antelope in particular thrive.

In the lush wooded savannas of the east

Impala eat a broad diet and are incredibly successful.

Their total population has been estimated

At more than two million individuals.

Only one antelope outnumbers them -

The springbok .

More than two-and-a-half million individuals

Range across the dry open plains of the west.

Here they dominate thanks in part to their ability

To eke out a meal even in the toughest conditions

And they feed on just about any greenery they find.

Together these two species

Are the most successful herd-living animals in africa.

Herding behavior evolved following the last ice age,

As the forests covering the continent receded.

Animals moved out onto the new grassy plains

For the first time.

They grew larger and began to cover greater distances

In search of food.

And it became important

For individuals to stick together in herds

So that they could easily find mates

And better protect themselves against predators.

Despite their abundance,

Springbok and impala almost never occur in the same habitat

And roughly follow the dry-wet divide.

Without them

Africa would be a very different place.

In the arid heartland of south africa

Lies the 220,000 acre karoo national park.

This is one of the country's most spectacular parks

Draped across the nuweveld mountains

That rise from open plains

Which millions of years ago were an inland sea.

Just about every animal living here is specially adapted

To surviving the desiccating conditions.

A small herd of springbok

Is grazing across the meager landscape of the scrubby plains.

Springbok are small gazelles

Standing roughly 27 to 35 inches at the shoulder

And weighing up to 100 pounds.

They're hardy characters

Capable of suffering through even the toughest of droughts.

Travelers through the karoo during the late 1800s

Wrote of gigantic herds of migrating springbok

So numerous they took all day to pass their camps.

These would move vast distances across the arid plains

Taking advantage of the unpredictable

And variable rainfall of the region.

These great congregations are a thing of the past.

In modern times

Farming has disrupted ancient migration routes.

And in the karoo,

Springbok are relegated to small herds

Sprinkled across the landscape.

300 miles east

In the world-famous kruger national park

In the wetter eastern parts of the country

A herd of impala is picking its way through the lush vegetation.

Life is very different.

The kruger, as it is fondly known to locals,

Is a gigantic swath of savanna bushveld

Stretching almost 5-million acres

Along the north eastern border of south africa.

One of the largest and most successful

Wildlife reserves anywhere on earth;

Kruger is crowded with animals.

Food is plentiful

And giant herbivores such as elephants and giraffes

Pick from the top branches of the trees while at their feet

Great herds of other browsers and grazers

Pick their way through the landscape.

It's also home

To some of the highest densities of predators in africa.

More than a hundred thousand impala

Munch their way through the thick bush.

Impala are taller than springbok,

Standing almost three feet high at the shoulder

And weighing up to 170 pounds.

With so much food and water available

A host of other browsers prosper.

A small family of kudu browses nearby.

Together kudu and impala often form loose mixed herds.

These aggregations do have some benefit.

In a world controlled by carnivores,

With almost half of all impala deaths caused by predators,

The more eyes on the lookout,

The better.

Predators also range across the arid plains of southern africa.

But animals here worry as much about avoiding the heat

And finding enough food

As they do about being eaten.

Where the borders of south africa,

Namibia and botswana meet

Is one of the dry western regions' most iconic reserves.

The kgalagardi transfrontier park.

Springbok are the most common antelope here.

During summer it's hot -

With midday temperatures over 100 degrees more often than not.

Springbok fare better than most.

They eat pretty much anything they find,

Switching between grass and herbaceous shrubs and succulents

As dictated by the conditions.

This young male is pawing up fresh shoots from the riverbed.

Once he's eaten his fill

He heads for the shade to digest his meal.

Springbok are masters at avoiding the heat.

They face their white rumps to the sun

Reducing the amount of heat absorbed.

White underbellies also absorb less of the heat

Radiating up from the ground below.

And they seek out shade to avoid the roasting conditions.

Gathering in the shade of these acacias has another benefit.

Springbok eat the fallen seed pods

And this is a valuable source of nutrition for them

In tough conditions.

The tree relies on the springbok to disperse their seeds.

The pods contain extremely tough seeds

That are resistant to the springboks' digestive system.

As the springbok move off

They carry the seeds with them before eventually

Depositing them elsewhere

In a nutrient rich pile of droppings -

Giving the seed every chance of germinating.

But one drawback

Of avoiding heat stress by gathering in the trees

Is that the close confines

Make it easier for predators to hunt them.

A lone cheetah is stalking down the dry riverbed.

They're the fastest terrestrial mammal

And can reach speeds of up to 70 miles an hour

For short distances.

The springbok have seen his approach.

He's still far away so they're not concerned.

They have the edge

As long as they get a head start on the cat.

Nearby a meerkat family is not so sure.

Meerkats are 10 to 12 inches long

And weigh a little over 2 pounds.

They're prime targets for raptors

And a host of ground dwelling predators

Including the cheetah.

They can't outrun cheetahs like the springbok can,

So they rely on burrows when threatened.

Just like the antelope, vigilance is key.

The family deploys sentries

To make sure they're not taken by surprise.

This allows the rest of the family

To root around for food below.

Even the ground squirrels

Take advantage of their neighbors' early warning system.

Each threat has its own unique call.

The sentry sounds a warning

And the family scurries below.

A close relative, the slightly larger yellow mongoose,

Is sharing the meerkats' home.

But he's no freeloader

And will often participate in burrow maintenance

And even help extend the underground network of tunnels

If required.

Most of all however, the yellow mongooses also benefit

From their hyper-vigilant house mates.

And vigilance is key to survival

When you're on the wrong end of the food chain.

No matter the habitat,

Whether in the dry west or lush east,

Herbivores always outnumber carnivores.

Life is easier in the east

Where there are plenty of plants available.

But plant matter is hard to digest.

Impala have an arsenal of tools to overcome the challenge.

This female is chewing the cud.

She's grinding leaves with her teeth

Adding enzymes all the time from her saliva.

Then she swallows.

And then regurgitates the food so she can chew it some more.

Every time the cud's swallowed

It's mixed with enzymes and microbes in the stomach

To break down the tough cellulose of plant material.

Without the repeated chewing and swallowing,

Ruminants wouldn't be able to obtain the nutrition

They require from the plants they eat.

It also means they spend less time foraging,

Giving them more time to rest

So they can avoid the heat.

Carnivores also rely on the success of this digestive system

Albeit indirectly.

With predators lurking,

Impala need to be vigilant in order to survive.

Large omni-directional ears give them excellent hearing.

And they have an acute sense of smell

Enhanced by their enlarged nasal passages.

Their eyesight is excellent

At detecting movement at great distances,

With a field of vision spanning 300 degrees of horizon.

Not all threats come from outside the herd however.

Only male impala carry horns,

Which they use in disputes over females.

This territorial male has spotted an intruder.

He takes up an aggressive posture

To warn the off the challenger.

They lock horns

And engage in a shoving match designed to determine dominance.

Fights seldom cause permanent damage

As long as the looser backs off.

Horns are specifically shaped for wrestling other males

Rather than stabbing and piercing,

Which gives them little value for defense.

Horns are a hindrance in close bushy confines

And females have no use for them.

On the dry open plains

Of the arid half of the country however,

It's a different story.

Here, both sexes typically bear horns

And scientists have wondered why.

One theory suggests springbok females have horns

So that their teenage sons resemble them.

There is intense competition

Amongst mature males in mixed herds,

So the longer young males look like females,

The longer they are ignored by dominants.

The latest theory suggests the females' horns

Have more to do with deterring predators,

Based on how conspicuous the animals are.

In the open, antelope are easily spotted by predators.

And horns are a deterrent,

So males and females both have them.

The taller you are, the more conspicuous you are,

So the bigger the deterrent you need.

Which explains why the gemsbok,

A much larger desert wanderer, has impressive horns to match.

Like springbok, these rapier-like weapons

Are borne by both males and females.

It's winter on the fringes of the arid great karoo

At the southeastern extent of the springbok's range.

Winter here is breeding season for springbok.

This territorial male is marking the bushes

With secretions from glands on his head.

He's advertising for mates and warning off rivals.

Tension is everywhere.

A young male ignores the warning

And the dominant male puts him in his place.

This territory is not big enough for both of them.

The dominant sees off the challenger for now.

On the plains of africa only the fittest survive -

The dominant male, while battered and bruised,

Has earned his right to mate with many females,

Passing on his genes to future generations.

Meanwhile the loser's family tree has come to an end.

Back in the wetter eastern parts of kruger

A dominant male impala is chasing a mate.

He's identified a female in estrus.

And is in hot pursuit.

She leads him on a merry dance

And the hapless male can only follow hopefully behind

Caught in her spell.

He flicks his tongue and nods his head enthusiastically

Doing his best to convince his would-be partner.

And eventually she relents,

Briefly pausing so that he can catch up.

Once mated,

He'll rarely show any further interest in her,

Even though she'll remain sexually active

For a few more days.

During this time

She'll be courted by other males and will almost certainly mate

With as many as four additional suitors.

The impala's range extends north

To the grassy plains of east africa.

There are no springbok here

But there are five other species of gazelle.

Two of them can be found here in the world famous

Ngorongoro crater in tanzania

Thousands of miles to the north.

Hemmed in on all sides

By the steep slopes of the ancient caldera,

This is one of the most remarkable landscapes in africa.

Fertile soils from the crater's volcanic history

Feed a menagerie of wildlife.

In ngorongoro grant's and thompson's gazelle

Often graze together.

Thompson's gazelle or "tommies"

Are the most common antelope in east africa,

Preferring the short grass of wide open plains.

They're remarkably similar in both size and color

To springbok.

It's thought this color pattern

Helps camouflage the herds from predators

Such as lions and cheetahs.

But camouflage only gets you so far

And all gazelles on the open grasslands of east africa

Are also fleet of foot.

Back in the dry, open riverbeds

Of the kgalagadi transfrontier park,

Athletic ability is paramount.

These springbok are pronking.

It's suggested this behavior advertises

An individual's athletic ability

To would-be predators.

It may also release pheromones

Or be an important alarm signal to the rest of the herd.

Other more romantic viewpoints however,

Suggest they're simply jumping for joy.

Even in more vegetated regions

Athletic ability is important to avoid the local predators.

Impala can leap effortlessly

More than 9 feet high and 35 feet over the ground.

They're also fast -

Even so they're no match for tsessebe

One of their nearest relatives.

Tsessebe are nearly twice the size of impala

And are the world's fastest antelope

Capable of reaching speeds of nearly 37 miles an hour.

Hartebeest and wildebeest are also close relatives of impala.

At first glance

It seems unlikely that these animals should be so close.

Impala are graceful

While everything about the wildebeest is awkward.

One thing all members of the family

Do have in common however,

Is they live out in the open and gather in herds.

And great herds attract predators like lions;

And leopards.

Living in a herd is advantageous.

There are many eyes to scan for danger.

So remaining in the herd is important.

Sick individuals or youngsters that lag behind

Are prime targets.

It's not only predators who track the herds.

A cattle egret is feeding on insects

Kicked up by passing feet.

Feeding alongside herds of antelope

Gives this individual one and a half times more food

Than a solo effort.

Red-billed ox-peckers also track the herds.

They're combing through their fur looking for an easy meal.

The impala tolerate the freeloaders

Because they're enjoying the grooming.

And the ox-peckers are able to remove annoying ticks

From even the most hard to reach places.

Ecto-parasites such as ticks aren't only an irritant -

They also carry disease.

So the impala benefit from the service.

An entire world revolves around what's left behind

By grazing antelope.

Copper dung beetles are collecting impala droppings.

There are more than 2,000 species of dung beetle.

This one is a roller.

He pats dung into a ball

And rolls it away before burying it.

Dung balls are food for the beetles and their young.

If he's lucky

His ball will attract a female and she'll lay her eggs in it.

He buries the ball safe underground,

Allowing the developing larvae to slowly eat their way

To the surface.

By burying these balls

He's also injecting valuable nutrients back into the soil

Facilitating plant growth and ultimately,

More food for impala in the great cycle of life.

Impala and springbok are very similar in many ways

But they almost never live in the same habitat,

With one exception.

Etosha national park in northern namibia.

Located in the arid heart

Of the kalahari desert in the south west of africa,

This 8,600 square mile park

Is renowned for its bountiful wildlife.

Animals here congregate at the reserve's waterholes

To survive the parched surroundings.

A black-faced impala has come down to the waterhole to drink.

She's instantly recognizable by her black facial markings.

The black-faced impala is a subspecies

That lives across angola and northern namibia.

It's better adapted to its desert home

Than the common impala of the east.

The two subspecies will readily hybridize if they mingle,

But black-faced impala are vulnerable

And etosha is one of their last strongholds.

For this reason,

The government of namibia tries to keep them isolated

But it's tricky.

Private game farms stocked with common impala

Surround etosha and so the government works

To keep them out of the national park.

Down at one of the lush waterholes of kruger

A herd of common impala drinks nervously.

Danger lurks in these waters.

Large crocs such as this one

Can be more than 13 feet long.

Spooked, the impala dash back to the safety of the bush.

But danger lurks here too.

The herd becomes separated,

Enabling a lone cheetah to pick off one of the females.

He'll gorge himself on his kill.

But cheetahs are the smallest of the big cats,

So he must eat quickly.

If scavenging lions or hyenas catch wind of his kill,

They will steal it.

Nervously he scans the surroundings.

Having eaten his fill he moves on.

As the seasons March on, the rains return.

It's spring in the moist savannas

Of the kruger national park in south africa.

The trees and bushes are bursting with new growth.

New arrivals throng the surroundings.

It's lambing season

And the bush is alive with youngsters.

Babies suckle from their mothers

For the first four and a half months.

Everyone in the family is jumpy.

Being small in this world makes them a target.

Leopards and jackals prey on youngsters.

So the females have adapted to synchronize their births.

With the young born in times of plenty,

There's enough food for lactating moms;

And the mass of youngsters swamps would-be predators

And reduces individual risk.

Still it's best to be on high alert.

A perilous road lies ahead for these youngsters -

Only half of them will survive their first year

To reach adulthood.

But those that do

Will grow up to take their place

In the great herds of africa.

Across the vast open spaces of southern africa

These two species dominate the landscape.

Springbok and impala are the most numerous antelope,

Numbering into the millions.

Though inhabiting different worlds, together

They're the central characters in the giant circle of life

That unfolds across southern africa.

From the dry deserts of the west;

To the moist savannas of the east,

These two species are pivotal

In the success of both plants and animals

Living across this divide.

For in africa

Springbok

And impala

Truly reign supreme.

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