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Planet Earth II (2016): Season 1, Episode 4 - Deserts - full transcript

The world's deserts force animals to come up with ingenious ways of coping with hostile conditions, giving rise to the most incredible survival stories on earth.


Imagine a world

where temperatures rise
to 50 degrees Centigrade,

where there's no escape
from sun, wind and dust.

Imagine a world
with almost no food or water.

These are the conditions
in one-third of the lands of our planet.

To live here

demands the most extraordinary
survival strategies.

This is the oldest desert in the world.

The Namib in southwest Africa.

It's been dry for 55 million years.

Life here for a hunter
is as hard as it gets.

A pride of lions,

one of the very few

that endures
this desert's scorching temperatures

and lack of water.

Hunting here presents special problems.

A herd of oryx,

the only prey within 30 kilometres.

Out here,
there is no cover for an ambush.

It will have to be a straight chase.

They have failed,

and each failed hunt
brings the lions closer to starvation.

To find enough to eat,

the pride continually searches
an area the size of Switzerland.

Three days and 150 kilometres later,

and still, no kill.

These are desperate times.

A dry riverbed
on the edge of their territory.

The only animals here are giraffe.

But these one-tonne giants
could kill a lion

with a single kick.

Lions seldom tackle
such formidable prey.

But this pride can't go on much longer

- without food.

The whole pride
must work together as a team,

if they're to succeed.

Two lionesses lead the chase.

Others race to cut off
possible escape routes.

The giraffe has the speed and stamina
to outrun the pride.

But it's being chased into a trap.

Up ahead, the lead female waits.

It's now up to her.

(MGM

Most lion hunts end in failure.

But no lions fail more often
than those that live in the desert.

Once again,

the pride must continue their search.

It does sometimes rain in the desert.

Here in the American West,

storms can strike
with devastating force.

After 10 months of drought,
millions of tonnes of water

are dumped on the land in under an hour.

Over millions of years,

sand and gravel
carried by the rampaging floods

have carved channels
through the solid rock.

Salt canyons, 50 metres deep.

In some places,
these canyons have widened

until the land between them is sculpted
into table lands and isolated pinnacles,

some of the most
dramatic landscapes on the planet.

The rain may be long gone,

but there is water here,

locked away within the tissues
of specialist desert plants.

Cacti are unique to American deserts.

They all hoard water,
storing it in swollen stems,

and protecting it
behind a barricade of spines.

They're so successful
that they dominate these deserts.

But this forest of spikes

can cause problems
for the animals that live here.

A Harris hawk.

It has developed special techniques
for hunting amongst the cacti.

Ground squirrels.

Prey.

At the first sign of danger,
they bolt for the safety of the thorns.

But the hawks have a tactic
to flush them out.

These are the only birds of prey
that hunt in packs.

Flying in formation,

they try to drive their quarry
into the open.

But this squirrel is staying put.

So now the hawks continue the hunt

on foot.

They're closing in from all sides.

Soon, all escape routes are cut off.

The squirrel is trapped.

The spines that cover
almost every plant in this desert

can provide protection and shelter
for many animals.

So, why should these spikes
be hung with corpses?

What kind of creature
could be responsible

for creating such a gruesome scene?

There's a mysterious killer
at work in this desert.

It's a butcher bird.

This little song bird uses the spines
as a butcher uses his hook,

to hold its prey as it dismembers it.

And with chicks to feed,
he also uses the spines as a larder.

He's been stocking it for weeks.

Hanging his prey out of the reach
of scavengers on the ground

ensures that his newly-hatched young
will never go hungry.

An ingenious solution

to making the good times
last in the desert,

if a little macabre.

Some deserts are so arid,

they appear totally devoid
of all vegetation.

Yet even these landscapes

can be transformed

in a matter of days.

The deserts of Peru
are amongst the driest in the world.

But just add a little water,

and plants
that have lain dormant for months

will burst into life.

And when a desert suddenly turns green,

even the most seemingly desolate

can become a land of opportunity.

No creature exploits
the greening of a desert more quickly,

or more dramatically,

than a locust.

Madagascar's arid southwest

has received
its highest rainfall in years.

Now, an army is on the march,

attracted by the smell
of newly-sprouting grass.

Locusts are normally solitary creatures,

but when food becomes
suddenly plentiful,

they come together
into an unstoppable force

that devours everything in its path.

But this devastation
is about to get a lot worse.

The locusts now transform
into winged adults.

And with conditions as good as this,

they do so three times
faster than normal.

Now, they are at their most voracious.

And with wings,
they can take to the skies.

Once airborne, the locusts can travel
over 100 kilometres a day

in their search for new feeding grounds.

A super-swarm of this scale
may only appear once in a decade.

This one extends
over 500 square kilometres

and contains
several billion individuals.

Between them, they will devour
40,000 tonnes of food in a day.

Nothing can strip a land
of its vegetation with such speed

and thoroughness as a plague of locusts.

When the food eventually runs out,
the whole army will die.

But not before it's devastated the land.

With no plants to bind them,

thin soils soon turn to dust
and blow away.

Now, these barren lands
are left to the mercy of the elements.

Scorched by the sun
and scoured by windblown sand,

desert rock is shaped into strange,
otherworldly landscapes.

These rocky deserts
may have a beguiling beauty,

but when they become this barren,
very little life can endure.

For many animals,

the only way to survive
the most hostile times

is to keep moving.

In the Kalahari,

brief rains have given way
to the dry season.

Food and water
are becoming increasingly scarce.

For these zebra, it's time to leave.

They are setting off
on the longest over-land migration

made by any mammal in Africa,

marching towards the scent
of distant rains.

As drought intensifies,

desert-living elephants
must also undertake long journeys

in search of water.

The older females can remember where,
even in times of extreme drought,

there may still be water,

and sometimes lead the herd

to a waterhole they may not
have visited for decades.

These zebra are almost
at the end of their journey.

This is what they've been heading for.

A rare waterhole.

In deserts,
most waterholes are short-lived.

They appear after rains,

but then vanish
almost as quickly as they came.

Animals have come here
from many kilometres around.

Yet, this can be a dangerous place
in which to linger.

A hundred kilometres away,
in the heart of the desert,

sandgrouse chicks are hatching.

It's safer for them to be here.

But being so distant
from water is a gamble.

With only their mother
to shield them from the sun,

if they get nothing to drink,

they will be dead within hours.

Their only hope is their father.

Every morning,
he makes the 200-kilometre round trip

to get water for the family.

Grouse from all over the desert
visit this oasis,

arriving together in large flocks.

And that is important.

There's safety in numbers.

The male snatches a drink,

but he also needs to collect
water for his chicks.

Using specially-adapted breast feathers,

he can soak up water like a sponge.

But it takes time,

and he is in danger.

Goshawk.

Sandgrouse here are their main prey.

Again and again,

the male sandgrouse risk their lives

in order to collect water
for their chicks.

This is why sandgrouse
nest so far from waterholes.

At last,

he's soaked up as much as he can.

Carrying a quarter
of his bodyweight in water,

he can now set off
on the long journey home.

He's back, and just in time.

He can give the chicks
their first-ever drink.

But he will have to undertake
this perilous journey

every day for the next two months,

until his chicks

can finally make the flight
to the waterhole for themselves.

It's July in the deserts of Nevada

in the western United States.

The hottest time of the year.

Bands of wild horses, mustang,

are converging on one of the last
remaining waterholes around.

Now, water not only offers them
the chance to drink.

It can also bring power.

If a stallion can control
access to water,

he will have secured mating rights
to the entire herd.

So stallions
try to dominate these pools,

fighting off rivals
who venture too close.

A stranger.

He's travelled 15 kilometres to be here

because the pools where he's come from
have already dried up.

With him come his females.

If he can't provide them with water,

they will leave him
for the white stallion

who already dominates this pool.

So he will have to fight.

There is everything to lose.

A broken leg or a shattered jaw
would mean a slow and painful death.

A missed kick,

and it's all over.

The new arrival has won.

And his prize
is more than just a chance to drink.

He has provided for his herd,
and in the process,

stolen his rival's females.

The white stallion's rule is over.

Desert life is not only shaped
by the scarcity of water,

but also by the relentless power

of the sun.

The highest temperatures on Earth
have all been recorded in its deserts.

Changes in the climate

mean temperatures here
are rising more than the global average.

And as deserts heat up,

they are also expanding.

Every year,

a further 150,000 square kilometres
of grass and farmland

are turning into barren stretches
of dust and rock.

In the heat of the day,

surface temperatures
can reach a scorching 70 degrees,

far too hot to handle for most.

But not for this shovel-snouted lizard.

Raising its feet off the ground in turn

enables each to briefly cool.

But even this dancing desert specialist

can't stand the heat for long.

One option is to find shade.

Dune grass, the only vegetation here,
provides virtually none.

But just beneath
the surface of the sand,

it is several degrees cooler.

Avoiding the extreme heat
imposes a rhythm on desert life.

And many animals here
choose the simplest option of all,

staying hidden all day

and only venturing out
in the cool of the night.

As darkness falls,

animals appear from seemingly nowhere.

And among them, inevitably,

are hunters.

One of the most voracious
nocturnal predators

is also one of the hardest to see.

This mysterious creature

hardly ever appears
on the surface of the dunes.

But there are signs on the sand
that can give it away.

It lives only here,

where the sand grains
are so perfectly dry and polished

that they flow almost like water.

It's no bigger than a Ping-Pong ball.

A golden mole.

It's totally blind,

but there's nothing
to see underground anyway.

Instead, it has superb hearing.

Its entire head acts as an amplifier

that picks up vibrations
through the sand.

So, to locate prey
on the surface of the dune,

it has, paradoxically,
to thrust its face into the dune.

Termites.

Not easy to catch when you're blind.

Far better to go into stealth mode.

Once below the sand,

it can detect the slightest movement,

allowing it to strike
with pinpoint accuracy.

Well, most of the time.

It can travel two-thirds of a mile
a night in search of its dinner.

And right now,
it has just detected its main course.

Little wonder it's sometimes called
"the shark of the dunes".

Food can be so scarce in the desert

that even at night,
animals can't afford to be choosy

about what they eat.

Israel's Negev Desert.

Otonycteris, the desert long-eared bat,

is on the hunt.

Most bats
catch flying insects on the wing.

But there are so few of these
in the desert

that this bat
must do things differently.

It has to hunt on the ground.

But what really sets it apart

is what it's hunting.

A deathstalker scorpion.

The venom of this species
is potent enough to kill a human.

Tackling it seems madness
for a bat weighing just 15 grams.

In the pitch black,

both predator and prey
are effectively blind.

But the scorpion has one advantage,

he can sense the approach of the bat
through vibrations in the sand.

Otonycteris must rely
entirely on its hearing.

If the scorpion doesn't move,
it won't know it's there.

The battle is on.

Armed with crushing pincers
and a sting loaded with venom,

this scorpion is a dangerous opponent.

A direct strike on the head.

Is it all over?

Not for this bat.

Otonycteris clearly has some immunity
to the venom,

but repeated stings
must still be extraordinarily painful.

And if the bat is not to go hungry,

it must catch another three scorpions
before sunrise.

Desert animals
have developed remarkable strategies

to make the most
of the rare opportunities

that come their way.

Although some deserts
may not see rain for several years,

most will hold a little water
in one form or another.

The trick
is simply knowing how to reach it.

Dawn in the dunes of the Namib,

and something magical is happening.

Moist air
lying over the neighbouring Atlantic

is cooled and blown inland,

forming fog banks
that shroud the desert in mist.

This precious moisture

lies tantalisingly out of reach
at the top of the dunes,

and it won't last long.

It will be burnt off by the sun
just hours after it rises.

Darkling beetles
race to the top of the dunes

to reach the fog before it vanishes.

Some of the Namib's dunes
are 300 metres high,

the tallest in the world.

For a beetle no larger than a thumbnail,

this is the equivalent
of us climbing a dune

twice the height of Everest.

But even more impressive

is what it does next.

Standing perfectly still,
facing into the wind,

the beetle does a headstand.

Fog begins to condense on its body.

Microscopic bumps on its wing cases

direct the water to grooves
that channel it towards the mouth.

Before returning down the slip face,

it will drink 40% of its body weight.

This little beetle

has learned how to conjure water
out of the air

in one of the driest places on Earth.

And it's not alone
on the top of the dunes.

Web-footed geckos use a similar trick.

Surely, few animals
go to greater lengths to get a drink.

Unfortunately, Namaqua chameleons
know that on foggy mornings,

the beetles coming down the dunes
are juicier than those going up.

The diversity of life

that thrives in a world
almost totally devoid of water

is truly remarkable.

Success in the desert

depends on an extraordinary variety
of survival strategies

that have evolved
over millions of years.

But our planet is changing.

The world's deserts
are growing bigger, hotter and drier,

and they're doing so
faster than ever before.

How life will cope here in the future

remains to be seen.

Next time,
we journey to the world's Great Plains.

Where spectacular gatherings of wildlife

cope with extreme change.

And surprising creatures survive

in unexpected ways.