The Central Andes mountains.
Thirteen thousand feet above sea level.
In this barren land
live some of the hardiest animals on the planet...
...surrounded by caustic lagoons.
Up here water is precious. It gives life...
...but also takes it away.
This is a land without mercy.
A land burned by the sun and starved of oxygen.
And yet, despite the odds, there is life here.
A life... of extremes.
Running the full length of South America,
the Andes are the world's longest mountain chain.
Halfway down, high peaks wall
the Altiplano.
It is the highest plateau outside of the Himalayas.
For most of the year the rivers run dry.
This lack of water and the cold thin air
make it an incredibly difficult place to live.
Vicuña have just the right adaptations,
including an unusually large heart and lungs
to cope with the scant oxygen.
Females live in groups dominated by a single male.
As the day warms up,
one of the females looks for a secluded spot to give birth.
The adult male keeps watch.
The fawn calls out, even before it is completely born...
...cementing the bond with its mother.
As the newborn wrestles with gravity,
Mom gives it some gentle encouragement.
The fawn's wet fur and the biting wind
are not a good combination.
To avoid getting too cold,
it must get on its feet and start moving...
...as soon as possible.
The fawn weighs just nine pounds
and has a lot of leg to control.
Eventually it grows more stable.
At 20 minutes old it's just about steady enough
for its first drink of milk.
Vicuña are extremely social animals.
It's time to meet the rest of the herd...
...just as soon as it can manage those legs.
Vicuña identify each other by sense of smell,
so there's sniffing all round.
The whole herd comes to greet the new arrival.
Although the fawn has met its first challenge
of simply getting up and moving, it's still very vulnerable,
and will be for the next few hours...
especially while it's still so unsteady on its feet.
By giving birth in the morning,
vicuña ensure that their young
have a chance to dry out before night closes in...
...bringing with it the bitterest cold
of these high Andean peaks.
The Andes run 4,000 miles down
the entire western edge of South America.
The widest part of the chain
is where the high plateau or Altiplano lies...
surrounded by tall mountains.
Here, high-altitude lakes are formed by glacier melt and rain,
unable to drain away.
But there are also white salt lakes,
like the Salar de Uyuni...
...and at the southernmost tip of Bolivia,
the Laguna Colorada.
A lake like nowhere else on earth.
As the intense solar radiation evaporates the water,
mineral salts are left behind.
The lake's vivid color is caused by microscopic algae
that thrive in its caustic waters.
The algae lure thousands of flamingos.
Three different species
the James's flamingo...
the Andean flamingo...
and the Chilean flamingo.
Each species has a slightly different strategy
for finding food.
But they all use their beaks to sieve algae...
and other microorganisms ...from the water.
One of the algae produces a reddish pigment
that not only turns the water pink
but also anything that eats the algae...
including the brine shrimp...
and the flamingos themselves.
At the beginning of the dry season, male and female
James's flamingos begin their courtship dance.
The display normally takes place around noon
and may last for a couple of hours.
The more experienced the birds,
the more elaborate and synchronized the dance.
In high summer, the Laguna Colorada
evaporates quicker than it fills...
leaving a fringe of crystalline salt.
But just northeast of here
lies a lake that has dried up completely.
The Salar de Uyuni, in Bolivia, is a former lakebed,
now deeply encrusted with lithium-rich salts.
It's the largest expanse of salt flats in the world... by far.
Its islands lie in a sea of snow-white salt.
And yet, within this dry arid landscape, life still prevails.
A giant hummingbird... the largest of its kind,
but still not quite an ounce in weight.
It lives on cacti that may be centuries old
and produce nectar that acts as high-grade aviation fuel.
Living at eleven and a half thousand feet,
the giant hummingbird has adapted to the thinner air.
In contrast to other hummingbirds,
its wings are broader,
and, instead of hovering at flowers...
...it comes in to land.
While the cacti are flowering,
the giant hummingbird has all it needs to survive.
In the dry season,
few clouds make it into these central highlands.
The nights are remarkably clear and bitterly cold.
A far cry from the heat of the day.
This extreme daily temperature shift
is yet another challenge
for the animals trying to survive here.
Within a couple of weeks, the infant vicuña
has fluffed up enough to weather these bitterly cold nights.
Ice crystals dust the vicuñas' backs...
but their fleece is more effective than cashmere
at keeping out the cold.
It also protects them from the extreme levels
of ultraviolet light found at this altitude.
The elements aren't the only threats to youngsters.
When the herd moves from its sleeping grounds,
down to the grassier river valleys below...
eyes are watching.
The dominant male stays on high alert.
Preferring the cover of night...
the puma goes in search of easier prey.
Come dawn, the flamingos are dancing on ice.
Along with their beaks, they have another secret weapon
in their fight for survival.
Flamingos have evolved a remarkable system of blood flow.
Warmth passes from their arteries
to the veins in their legs, preventing frostbite.
With three seasons in a single day,
life on the Altiplano can be unpredictable.
Something's not right...
...with the new vicuña infant.
It shouldn't be alone.
Somehow, it's become separated from the herd.
The mother searches everywhere...
...listening for a familiar cry.
Her baby desperately needs its milk...
but it's heading in the wrong direction.
Ahead of it lies the salt flats,
and possible death by dehydration.
The mother is on the right course.
But the fawn is heading further away.
Finally, she sees it.
Soon, it's suckling once more.
Salt pans are a haunting memory of long-lost lakes.
But remnants of the Altiplano's ancient water world
can still be found...
...at Lake Titicaca.
Here, glacier melt and rain collect
to form the largest lake in South America.
And at more than twelve and a half thousand feet
above sea level...
the highest large lake in the world.
With little oxygen in the air or the water,
the lake's inhabitants
need very special adaptations to survive.
The loose baggy skin of the Titicaca water frog
increases its surface area,
allowing it to extract more oxygen from the water.
This giant one-and-a-half-foot-long frog
never leaves the water, and never breathes the air.
It gets all the oxygen it needs entirely through its skin.
If oxygen levels drop, the frog performs pushups.
This increases water flow over its thin baggy skin,
and boosts the amount of oxygen it absorbs.
It's the perfect collection of adaptations
for an aquatic life at high altitude.
This extraordinary land was forged by volcanic forces...
and is still warmed by magma
boiling beneath the earth's surface.
The sulphurous springs at Sol de Mañana in southwest Bolivia
are 16,000 feet above sea level.
Although the landscape looks ancient,
it's one of the youngest and most dynamic
parts of the earth's crust.
Boiling mud pools are a window into the hellish world below.
The Altiplano sits above
a partially molten magmatic soup...
the force behind many of the volcanic eruptions
that have shaped this land...
and many of the eruptions still to come.
In these difficult conditions only the most
exceptional animals can survive, let alone thrive.
The Chilean flamingos have paired up and made nests
from the mineral-rich mud
around the margins of the Laguna Colorada.
Families cluster together, perhaps as a communal defense
against predators such as puma and the culpeo fox.
There'll be no escaping the neighbors
for the next few weeks.
Each couple produces a single egg that rests on a mound
about a foot across and four inches high...
just in case the water level rises.
Some animals might never get to breed.
A herd of young male vicuña wanders a barren no-man's land,
excluded by dominant males but not yet old enough...
or strong enough... to defend harems of their own.
The rocks around are veined with precious minerals,
but blades of grass are much harder to find.
There is almost nothing to eat here...
unless you're after vicuña.
A culpeo fox is scavenging for his next meal.
The vicuña are blissfully unaware.
It seems it's in luck.
A mother and fawn.
But this is no fresh kill.
Unfortunately for the fox,
the carcasses have been here a while,
and the best bits have already been taken.
The remains are as dry as the land.
The fox is forced to carry on its way.
Moving down the western slopes of the Central Andes,
to the foothills...
...the land turns to desert...
...and becomes one of the driest places on earth.
Rain showers can be years apart,
so cacti need long-term water storage.
Animals too have adapted
to get through times of punishing drought.
A marsupial called the elegant fat-tailed mouse opossum
stores fat in its tail and draws on it as needed.
It can even shrink its internal organs
to save energy when food is scarce.
Hunting at night avoids the crippling heat of the day.
But the red scorpion also works nights.
Its sting is not the most toxic,
but it's inflammatory and very painful.
One of these animals is walking towards a nasty surprise.
But which is predator and which is prey?
By the light of the moon,
the opossum and the scorpion close in.
The sharp-toothed hunter disarms its venomous prey.
The elegant fat-tailed mouse opossum
gets a much-needed meal...
and... thanks to that elegant fat tail...
it can save some for later.
On the Altiplano, night-frosts and relentless winds
have carved hard rock into dramatic sculptures...
...creating ideal homes...
...for viscacha.
These rock-hoppers look like rabbits,
but they're more closely related to guinea pigs.
Crevices in the shattered rock offer shelter... and escape.
Only extreme survivors, like viscacha,
can make a living from such sparse vegetation.
To squeeze that bit more from their low-protein diet,
they eat their own feces, absorbing any nutrients
that were missed the first time round.
Not having to graze so much enables the viscacha
to conserve energy in the midday sun...
...and to sleep.
But not too deeply...
Agile young viscacha
are a favorite food of the rare Andean cat.
And this one has another mouth to feed.
It's a bad day for the viscacha...
...but a good day for these highly endangered cats,
of whom there may be as few as 1,500 left in the wild.
When the rainy season finally arrives in the Altiplano,
so too does the grass.
The baby vicuña is now
perfectly insulated against the wet,
but it'll be a while until it's fully weaned onto grass.
Here, the rainy season lives up to its name.
Surrounded by mountains and with no outflow,
the level of the Laguna Colorada keeps rising.
The rain also floods the vast Salar de Uyuni salt flats.
Just inches deep in water,
the Salar de Uyuni becomes a mirror to the heavens.
Higher up, the rainclouds meet a wall of cold air.
Undeterred by the new blanket of snow,
the vicuña herd makes the daily migration
from its higher, safer sleeping grounds
to these lower grazing areas...
...though their normal camouflage is blown.
At six weeks old, the youngster
has done well to survive this far.
But it's not out of trouble yet.
Up to 30 percent of vicuña babies
are taken by puma or fox within their first four months.
But the ever-watchful puma's lost its cover too.
Without the element of surprise it can't keep pace with vicuña,
who can sprint from a standing start.
So, the herd can relax a bit.
But the stormy weather has been catastrophic
for some of the flamingos.
Nests lie flooded and abandoned.
Other flamingos have been luckier.
Eggs resting that bit higher above the cold water
have already hatched.
For the first two months of their life,
chicks need their parents.
But they'll start exploring after just one week.
Some strike out more adventurously than others.
But it's easy for a hatchling to stray too far from home.
It's not long before one of the parents realizes
that its chick is missing.
It listens out...
Parents and chicks can recognize each others' calls.
Even so, at this tender age, it's a long way home.
Until its filter-feeding beak matures,
the hatchling can't eat solid food.
Instead, it relies on crop milk...
a secretion produced in glands
along the parents' digestive tracts.
The fact that both parents can produce this fatty milk
is a distinct advantage for flamingo chicks,
though the heavy rains mean
there will definitely be fewer of them this year.
Storms pass, but their effect lingers on.
On the lower foothills of the Central Andes,
once-dry land begins to bloom.
Long-dormant seeds wake, and germinate.
A bounty like this doesn't happen every year,
so animals are quick to exploit it.
It's a brief flourish,
but it's enough for the flowers
to pollinate and disperse their seeds.
Higher up in the Altiplano, the streams still flow.
It's a time of plenty for the vicuña.
With lots of food to go round,
the youngsters can relax
and enjoy the intensely social side of vicuña life.
But, within months, the dominant male
will force the adolescents out of the group.
In preparation, the young vicuña
are slowly building their strength.
Their heart muscles are already packed with capillaries
for channeling the little oxygen there is up here.
Of course, the best way to build strength... is to play.
As they grow, they will develop their acceleration and agility,
and attain a top speed of around 30 miles an hour.
For now, they're just having fun.
Countless generations of vicuña
have established their place on the vast Altiplano.
Like all the animals here,
they live surrounded by huge active volcanoes,
rarified air, and poor salty ground.
In the extreme conditions of the high Central Andes,
to survive at all is a triumph against the odds.
Proof that life can flourish...
...even in the most inhospitable of places.