Original subtitles

in the southern reaches of africa's great kalahari basin,

the air quivers with heat.

everything is made tough.

ancient rivers harbor water -

deep underground.

these are hidden lifelines

creating a fragile link to survival.

this is a land of deep thirst,

and raw beauty.

this is the kgalagadi transfrontier park.

the kalahari basin

is one of southern africa's most striking landscapes.

millions of years of erosion have formed the sandy soils

that define this vast high altitude plateau.

a thirsty wilderness covering some 345,000 square miles.

within this expanse lies the kgalagadi transfrontier park.

it straddles the border between south africa and west botswana

and covers almost 14,000 square miles.

life here is hard,

characterized by long dry months

and unpredictable sporadic rains.

in parts as few as 6 inches of rain fall in a year.

most of this vanishes quickly,

drained through the sandy soils

and evaporated by the beating sun.

but two unlikely veins of life

weave their way through the park,

ancient dry riverbeds

that hold earth's most precious resource deep below.

here camelthorn trees grow tall,

their long roots tapping into the hidden water.

their boughs becoming havens

and their seeds food for many desert inhabitants.

smaller grasses

and herbs

take advantage of nutrient rich soils around them.

even with these resources,

the hardy creatures of the kgalagadi

have had to adapt to survive this harsh environment.

from colonies of master builders.

to herds of herbivores.

these in turn

feed a host of desert predators.

from africa's most iconic,

to the diminutive and shy -

hunting for their living on land

and from the air.

and completing a food chain

in which every link relies on the perseverance of the others.

it's mid winter;

the height of the dry season in the park.

when quality plant food is hard to find.

herbivores congregate in dry riverbeds,

where underground water can still support

the toughest plant life.

but crowds can attract danger.

africa's most powerful hunters live here.

and few are fiercer than lions.

these sisters are in the prime of their lives.

they've lived together since birth,

spending much of the dry season around the riverbed,

attracted by the abundance of potential prey.

their pride is ruled by a coalition

of a young male with a growing mane -

and his more imposing ally.

he weighs in at around 440 pounds,

capable of bringing down prey four times his own weight.

with animals concentrated in the riverbeds,

the lions have prime real estate.

but with low game densities beyond the riverbeds,

their range could be as big as 1,000 square miles.

lions dominate the kalahari food chain,

hunting mainly by the cover of darkness -

and sleeping away most of the hot day.

but they're not the park's only predators.

for another group of the kgalagadi's iconic cats,

the day's schedule will soon have a lot more in store.

in the nossob riverbed, a family of cheetahs is about to stir.

they're one of the few species of diurnal cat

and spend the night lying low

to avoid the threat of their fierce competitors, like lions.

cubs are vulnerable to attack by a range of predators,

and in some areas fewer than half

will survive past three months.

but this mother has done a remarkable job

in successfully raising her four cubs

to the brink of independence.

when they reach around 18 months

the youngsters will leave their mother,

and so they must take every opportunity

to learn to kill.

clocking top speeds of more than 68 miles per hour,

these are the fastest land mammals on earth.

unlike other cats their claws are permanently exposed,

providing high-speed traction on the loose, sandy terrain

like an athlete's spikes.

and, while they may not be the fiercest predators,

they are among the most efficient in the kgalagadi.

enjoying success in two out of seven hunts -

a rate almost twice as productive as the area's lions.

here in the riverbeds,

their favorite prey is the dainty springbok.

nearly 70 percent of the kgalagadi's springbok

will fall prey to cheetahs.

but a medium sized antelope doesn't go far

when spread between five hungry cats.

today's lesson will focus on bigger prey.

the cheetah head off to look for a more substantial meal.

so for today, these springbok can feed peacefully.

with its triple-tone coat,

the springbok is one of africa's prettiest antelope.

but its pelt

is also of particular importance for survival here.

summer days in the kgalagadi

regularly top 105 degrees fahrenheit,

but even in the cooler winter months,

temperatures can exceed 85 degrees.

to deal with the heat,

springbok turn their white rumps in the direction of the sun,

reflecting up to 95 percent of its rays.

but in this world of sun baked sand,

the ground acts as a mirror,

reflecting hot sunlight from below.

the springboks' white bellies repel these rays too,

preventing overheating.

this enables springbok to spend more time in the open

while other animals retreat,

looking for the refuge of shade.

for shade the kgalagadi's animals rely largely

on one of the most iconic and important

of the park's plant species.

the camelthorn tree.

reaching 50 feet tall,

these grow prolifically along the kgalagadi's riverbeds.

but the park's rivers rarely flow.

they see surface water only once every eleven or so years.

the real source of moisture lies deep beneath the ground

and the camelthorns access it

with taproots descending as far as 195 feet below the surface.

using this moisture to grow tall and strong

the camelthorns perform a number of functions

crucial to life in the kgalagadi.

none is more important than their role as scaffolding.

this mass of sticks may seem lifeless from a distance.

but a closer look reveals a hive of activity.

it is home to a colony of incredible architects.

sociable weavers.

at five and a half inches in height,

these weavers weigh just less than an ounce.

but when they combine their powers for design,

their homes can spread 23 feet through the camelthorn canopy,

and weigh in at more than a ton.

males and females all contribute to building the mega-structures,

which can house as many as 300 pairs.

during the day the nest is akin to an international airport,

abuzz with business.

with arrivals,

departures,

and hundreds of flights.

all masterfully avoiding each other in the immediate airspace.

most of the weavers will spend their entire lives

living in this nest.

and it's essential to their ability to survive

in the park's extreme weather conditions.

the thick walls offer excellent insulation,

meaning that even on the hottest days

the internal temperature

never rises above 87 degrees fahrenheit.

on freezing winter nights

the birds' shared heat

can raise the internal temperature

by as much as 41 degrees.

some of the camelthorn trees in the kgalagadi

are 250 years old.

these have continuously

supported sociable weavers' nests for more than a century

or almost thirty generations.

the trees thrive in the riverbeds

where nutrients collect,

leeched from the sand of the surrounding dunes

by the occasional rain.

but there are places in the park where nothing grows at all.

the kgalagadi is dotted with multiple

broad, barren depressions known as pans.

these are the last remnants of long since deceased rivers.

when erratic kalahari rains do fall,

surface water collects on the compacted clay

only to evaporate under the hot sun.

minerals and salts are left behind

which over time

become too concentrated for plants to grow.

for a pair of desert experts like these ostriches,

there is no land too foreboding.

the largest species of bird in the world,

they stand at six and a half feet tall and weigh 220 pounds.

they cannot fly, but make up for this by running

at up to 43 miles per hour,

7 miles an hour faster

than a lion.

more remarkable than their speed

is their ability to survive in the heat of the kgalagadi.

they have exceptionally low water demands,

getting almost all of the moisture they need

from their mostly plant based diet.

for the ostriches

there is little time spent resting as they spend more than

60 percent of the day striding the landscape,

looking for food.

while nothing grows in the middle of the pan,

animals still visit these open wastelands.

they will congregate at these hollows

and eat the soil in small quantities,

taking on the minerals as a supplement to their diet,

which is lacking at this tough time of the year.

the dry earth is not the only source of extra minerals

available in the kgalagadi.

this female gemsbok is heavily pregnant.

in the dry winter her diet is lacking much needed nutrients,

which will become ever more important

when nursing her newborn.

to make up for this lack she turns to an unlikely source -

the rib of a large herbivore.

perhaps a wildebeest or perhaps even another gemsbok.

she'll chew the bones of other animals

to extract minerals such as calcium and phosphorus.

it's an example of nature's innovation

which allows animals like her

to survive in incredibly difficult habitats.

she belongs to possibly the most well-adapted and iconic

of all the desert dwelling species.

at about 4 feet tall at the shoulder,

gemsbok weigh around 530 pounds.

these majestic antelope are known for their horns,

which average more than three feet long

from ribbed base to razor sharp tip.

an injury at a young age can cause a deformity in growth.

this could put the pregnant cow at a disadvantage

when it comes to defense against predators.

thus far she's been unhindered by the deformity -

able to live life as a productive member of the herd.

but things are different for the bulls.

gemsbok are one of the few antelope

in which the horns of males are shorter than those of females.

but they're also thicker and stronger,

better preparing their bearers for battles for dominance

and the right to mate.

when two bulls come to a stalemate,

only a third can come between them.

the skin around bulls' necks is up to a quarter inch thick

to protect them during these skirmishes.

the gemsbok survive

thanks to a range of adaptations to life in a parched land.

they are able to go much of their lives without drinking;

getting the moisture they need from their food instead.

to make this possible,

the gemsboks' bodies are geared toward saving water.

while many mammals will pant or sweat to cool down,

both processes waste water.

instead, the gemsbok can allow their normal body temperature

of 96.2 degrees fahrenheit

to rise to a staggering 113 degrees.

they can handle a hot body

but an overheated brain can be life threatening.

to counter this,

in the gemsbok's moist cool nasal passages

there's an extensive network of blood capillaries.

this cools the blood,

keeping the animal's head at a safe temperature

while the body temperature soars.

the gemsbok will then lose the excess heat in the cooler night,

which is also when they do most of their grazing.

at night even dead grass can absorb 40 percent of its weight

in airborne moisture.

it's enough to satisfy

the gemsboks' low water requirements.

and it allows them to spend more time in the dunes

than their smaller antelope counterparts.

in the southwest portions of the park

lie dune fields extending for a full 500 miles.

their sand is turned ochre red

from iron oxide enveloping the grains.

here, tough grasses take hold along the ridges.

and in some areas, grow in thick, dense swathes.

it's an apparent banquet for animals like the gemsbok.

but there's more to this grass than meets the eye.

known as kalahari sour grass,

its young shoots soon toughen and secrete an acidic substance

which is unpalatable to the animals

and causes them skin irritations.

an inedible sea of seeming abundance

as cruel as any desert mirage.

but not all of the kgalagadi's plants are as deceptive.

in the nutrient-rich riverbeds,

the camelthorns are a lot more than just scaffolding for nests.

in the driest time

they produce large seed pods.

their silvery coat reflects the sun's hot rays

just like the springboks' rumps,

thus minimizing evaporation.

low in tannins and high in protein,

these pods are an important source of nutrition

for many of the kgalagadi's animals.

and this herd of wildebeest cashes in on the feast.

in order to germinate,

the hard-shelled seeds must pass through their digestive systems

where enzymes break down their outer shells.

they will soon be spread by the wildebeest

in repayment of the tree's nutritious favor.

in the cooler part of the day,

the herd takes to the riverbed to lie in the sun.

with many eyes on the lookout, they can take time to relax.

but a herd in the nossob riverbed

is about to have an altogether more dramatic day.

the cheetah family have been on the move all morning

seeking a meal fit for five

and they've spotted the wildebeest.

the day's hunt is about to begin.

the cats keep a low profile, getting as close as possible.

suddenly the chase is on.

a calf injures itself in the chaos of the herd.

the cheetahs surround it but are cautious of the bucking prey.

outnumbered five to one,

this will surely be the end for the young wildebeest.

but the cheetahs are inexperienced.

and the calf isn't going to go down without a fight.

they're at a loss of how to make the kill.

tired from the exertion of the chase,

the cheetah retreat to the shade to recover their strength.

and the wildebeest has a chance to get away.

but they're not about to let it go that easily.

and it's every wildebeest for itself.

the injured calf is abandoned to its fate.

barely able to carry its own weight,

the calf manages to keep eyes on the closest threat.

it matches its harassers, move for move in a terrifying dance.

eventually, exhaustion begins to take hold.

in both predators and prey.

after a drawn-out saga,

the day comes to the strangest of ends.

the cheetahs abandon the opportunity.

despite the huge investment of energy, they will see no reward.

the calf's refusal to surrender

has bought it extra time.

a fine example of the fact

that there are few foregone conclusions

in this unpredictable land.

but as night falls,

a different set of threats may present itself.

and with lions around,

the calf will be lucky to make it to morning.

as day breaks the kgalagadi's springbok

are making the most of the early hours.

while they rely largely on fresh grass after periods of rain,

springbok have adapted to make the most of scant resources

during the barren winter.

and in some cases these occur in an unlikely location;

beneath the bone dry sands of the auob riverbed.

the antelope uncover hidden roots

before plucking them with dexterous lips.

by adapting their diets,

springbok can sustain themselves well enough

to continue with life as usual,

despite the apparent lack in their environment.

and even in these tough times

the males are preoccupied by the desire for dominance

and mating opportunities.

this male moves between the surrounding females,

checking each in turn for reproductive readiness.

but they're unresponsive.

the brief rut and mating season

happened months ago after the wet season

when the herd was in prime condition.

now the females share none of the male's interest.

young males will still size each other up.

but their contests hold none of the intensity

that will occur when the herd is at full fitness.

while the springbok have had an early start to the day,

another group of kgalagadi icons are later to rise.

a family of meerkats.

the pack takes great caution

before leaving the safety of the burrow -

scanning their surroundings for threats.

and for good reason;

they have pups with them.

like the sociable weavers, meerkats work together

to insulate themselves from the extremes of the environment.

but instead of building up they dig down,

making their homes beneath the ground.

and they're not the only ones living here.

their roommates, the yellow mongooses, have had a sleep in.

but they have less patience when it comes to finding breakfast.

and are first to go hunting for insects.

following their lead the meerkats venture out,

slowly at first.

they soon come across their other neighbors

the ground squirrels.

they too live as a family, with mom keeping a careful eye out.

unlike the others,

the squirrels are satisfied with a mainly vegetable based diet -

nibbling away contentedly.

these three social species

happily share their turf with each other

but will all jealously defend it

against rivals from their own species.

as the day goes on, each makes the most

of what their surroundings have to offer.

while the mongooses and squirrels

will split up to forage as individuals,

the meerkats stick together,

watching each others' backs to the last.

while the meerkats' day is just beginning,

one of the kgalagadi's other subterranean dwellers

is getting ready to head back underground.

this cape fox spent the cold winter night hunting alone,

digging for its favorite prey of mice.

it enjoys the morning warmth

before heading to sleep in its den,

where it will raise its pups come early summer.

weighing in at 11 pounds,

the cape fox is the smallest canid in southern africa.

it's also the only true fox living here

and is endemic to the region.

the little predator is vulnerable to bigger carnivores

and it must return to safety below ground.

the entrance to its den

is carefully concealed beneath the branches

of one of the kgalagadi's hardy shrubs.

these plants are almost as well adapted

as the animals which eat them.

like the 'three-thorn',

so named for the way it grows,

always branching off in increments of three.

and the 'black-hook', named for its dark thorns.

to survive here these plants have tiny, thin leaves

to minimize water loss through evaporation -

and thorns to avoid being devoured in large quantities.

like the smaller shrubs,

thorns are crucial to the survival of camelthorns.

this young tree will eventually grow

to resemble the comparative giant behind it.

and when it does, it will serve another important purpose

for the kgalagadi's birds,

giving them branches on which to perch.

red headed finches are the same size as the sociable weavers.

these grain eaters will gather in flocks

numbering in the hundreds.

unlike many in the kgalagadi they must drink frequently,

congregating around the park's rare water sources.

but the finches are vulnerable to predation by birds of prey,

and they dare not relax on open ground -

diving in for two sips

before returning to the cover of the camelthorn's branches.

but as much as the camelthorn serves them

with a protected perch,

it provides the same service

to the birds of prey that hunt them.

the kgalagadi is a hotbed of raptor activity.

this southern pale chanting goshawk

will prey on small birds like weavers and finches.

but its favorite food is small mammals.

it devours its latest victim in the branches of a camelthorn.

the kgalagadi riverbeds provide ideal habitat for the goshawk.

open ground leaves rodents visible

and the branches of camelthorns provide high perches

from which to launch diving attacks.

and when mice are few and far between,

at around 80 sociable weavers in less than a mile of riverbed,

there's no shortage of food for the goshawk.

having eaten its fill it uses the tree for one last purpose -

cleaning its sharp beak

by rubbing it against the rough bark.

the goshawk isn't the only hunter

that relies on camelthorns.

while their branches are a launching pad for the raptor,

they also provide a favorite resting place

of another of the kgalagadi's cats.

but this little predator may seem out of place

in its wild environment.

the african wild cat looks surprisingly domestic.

mainly active at night,

it spends much of its day relaxing in these branches.

its stripy legs are perfectly camouflaged

against the tree's gnarled bark.

at around 11 pounds

it could easily be confused with a domestic tabby cat,

distinguished only by its longer legs

and the rufus coloring behind its ears.

it was cats like these that were first domesticated

6,000 years ago in ancient egypt

to control rat populations.

and like those ancient ancestors this wild cat's favorite prey

are mice and rats.

high densities of rodents mean that it can get

all it needs in a small territory

of less than half a square mile.

unlike the cape fox

it finds daytime safety above the ground,

in the shaded boughs of its favorite tree.

this predator, as familiar in its appearance

as it is strange in its wild setting,

is yet another reminder that not everything is as it seems

in this unpredictable land.

after a good grooming session

the african wild cat settles down to sleep the hot day away.

here it will remain until evening

when it heads out to hunt,

taking its place alongside the bigger predators

that prowl the park by night.

the riverbeds carving their way

through the kgalagadi transfrontier park

are havens of life in a harsh land.

here tall trees have grown for centuries,

providing both substance and structure

for life to persist.

while living in this thirsty land is challenging,

the park's creatures are perfectly adapted to survive -

enjoying success,

and persevering through failure.

relying on teamwork,

and their own determination -

they defy the odds.

carving out their own place in the cycle of life

that drives this great park.

together these creatures bring vibrant life

to this vast wilderness

in the heart of the kalahari.