All habitats present challenges to life,
but few more so than the desert.
(wind blowing)
The hottest, driest, most hostile landscapes
seem foreboding to us.
(gentle music)
The conditions can be deadly,
but still a hardy band of unique animal and plant species
have adapted to face the challenges head on.
From cactus to camels,
to hedgehogs,
and even humans.
Each one finds its own ways
to exploit and conserve food and water
in its daily struggle for survival.
(waves whooshing)
Deserts are a huge part of our planet,
but they are getting bigger and harsher because of us.
Thankfully, it doesn't take much to give them a hand
and to reveal the enduring treasures of the desert.
(gentle music) (insects chirping)
You might expect to find deserts
around the center of the Earth, the equator,
the part of the planet closest to the sun
and exposed to its most direct rays.
But instead, the equator has a band of rainforest.
On this hottest part of the globe,
the sun heats the ground,
and from it hot air rises.
When it gets higher, the air cools,
and rain falls,
keeping the forest well watered
and under the protected cover of clouds.
(rain whooshing) (thunder booming)
(gentle music)
Once the rain has fallen,
the dry air is pushed out to the sides
by more hot air rising below.
It falls 15 to 30 degrees north or south of the equator.
And this is where most of the world deserts are formed.
Like the biggest, the Sahara.
The largest hot desert,
almost as big as the United States,
the Sahara straddles many countries across Northern Africa.
Much of the region is a sea of sand
punctuated by dramatic shifting dunes,
some more than 150 meters tall.
The Sahara is consistently one of the hottest places,
typically over 40 degrees,
which makes it hard for life.
(wind whooshing) (dramatic music)
But there are some tough inhabitants.
There's an aray of small animals,
(gentle music)
making up the base of the food chain.
Even the thin-skinned European green toad
can eek out a living by lurking in the shadows.
(fox sniffing)
Dune beetles have rich bodies
to collect and channel the morning dew into their mouths,
making them the perfect water source
for this little predator,
the smallest member of the dog family.
(wings flapping)
The fennec fox might be tiny,
but its ears are anything but.
(wings flapping)
They are an adaption,
increasing the surface exposed to any breeze
to help him lose heat.
(fox flapping)
His thick coat is sandy,
not only for camouflage
but pale to reflect the sun by day
and thick to keep him warm at night.
And hairy feet stop this little fox
from scolding his toes on the baking sand.
(fox sniffing)
With these adaptations, the fennec fox can thrive,
and comfortably forage among the dunes.
(fox munching)
(gentle music)
At first glance,
there isn't much animal life in the desert.
But that's because of the temperature.
To beat the heat,
most creatures wait for the cool of night.
(insects chirping)
Specially on the scolding plains of Australia.
(lively music)
Spinifex mice are more comfortable exploring
under the cover of darkness.
In most areas,
coldblooded lizards like to bask in the sun's heat
to fuel their bodies.
But here, many are more active at night.
(tense music)
The knob-tailed gecko is no threat to the mice.
(gentle music)
But it could be in trouble
when a mouse lookalike starts foraging.
It might look like a little rodent,
but the fat-tailed dunnart isn't at all related.
It's a marsupial,
a tiny cousin of the ferocious Tasmanian devil.
The little guy's about the length of your thumb,
but that doesn't deter his carnivorous confidence.
Though luckily for the gecko,
he's after crickets tonight.
(fat-tailed dunnart munching)
As the sun appears on the horizon,
these creatures will seemingly vanish,
retreating to their burrows.
And a new cast appears.
(wind blowing) (gentle music)
Some animals are crepuscular,
meaning they are most active at dawn and dusk.
This time in the vast sways of desert
that straddle Central Europe.
A quick sniff and her nose tells her
it's safe to leave her den.
When you are as small as a long-eared hedgehog,
it pays to be careful.
She begins her daily foraging trip
across the sand dunes of her home
in the deserts that straddle Central Eurasia.
She's looking for breakfast
and hoping to find it before the sun bakes the sand
until it's too hot to touch.
She's a fan of little creatures.
70% of her diet is crunchy insects
that will give most of the moisture she needs.
She's not the only one looking for a bite.
A toad-headed agama is basking
in the relative cool of the morning.
He watches the competition.
Until she gets a bit close.
(dramatic music)
He transforms himself into a movie alien.
Lipids are umbrella-like flaps of skin
he can expand to freak out would-be attackers.
Finding enough food in the desert is tough.
Neither has time to worry about the other.
(gentle music)
Though breakfast for either of them might be off.
(wind blowing)
In the desert, sandstorms can be sudden and severe.
(wind blowing)
The lizards has a neat trick.
A quick shimmy and he's buried enough
to shelter from the storm.
The hedgehog wisely retreats to her burrow.
This is a typical day for creatures of the desert.
Trying to beat the heat, find food,
and survive the weather
in one of the most hostile environments on the planet.
(wind blowing) (gentle music)
Deserts can be found on every continent
and cover 1/5 of the Earth's surface.
They are defined
as receiving less than 25 centimeters of rain a year.
And crucially lose more moisture to evaporation
than they gain from rain.
Because there's little wetness,
they don't get many clouds,
so temperatures get very cold at night,
often below freezing.
And exceptionally hot during the day,
50 degrees centigrade or more.
We typically imagine deserts as sandy,
but they can be rocky too.
(elephant trumpets)
Usually without much vegetation because of the conditions
and without plant roots to stabilize soils,
the earth blows away, revealing sand,
gravel and rocks.
(gentle music)
Sometimes offering windows on long lost landscapes.
The bizarre pillars of rock in the Pinnacles Desert
in Western Australia
are made from the remains of tiny shellfish,
indicating that this area was once ocean.
No one is too sure what carved the strange structures.
(birds chirping)
It might have been minerals leaching into the soil
and cementing them.
Or the boring roots of long lost trees
might have compacted the ground and created entry points
where eroding rain water could seep in.
Either way, there are no trees now,
so the galahs have to make due
with nesting on the pillars instead.
The otherworldly landscape seems a far cry
from its ocean origins.
(waves whooshing)
Though water and deserts
are not things we associate together,
some deserts are actually found on the coast.
It's the ocean itself that causes them.
Cold water currents,
in this case the Benguela,
bring water from the poles to warmer climates.
The cold water below makes the sky shed its water
as rain or mist
before it reaches the coast,
leaving dry areas in land.
Coastal deserts.
This one is the Namib,
the oldest desert on the planet.
It's been arid for at least 55 million years.
(wind blowing)
The landscape has been thwarted on both sides
by its geography.
Trade winds blow across Southern Africa from the east.
But when they hit the Drakensberg Mountains,
thrusting them skywards,
the air cools and moisture droplets form.
(wind blowing)
(thunder booming) (rain whooshing)
The mountains get rainfall,
but the deserts beyond get nothing but hot dry winds.
And to the west,
the cold ocean claws back the moisture too.
(seals barking)
But there is one benefit.
The cold air of the coast meeting the warmth of the desert
causes a regular bank of fog,
a hint of moisture that drawls in across the dunes.
(gentle music)
Just enough to feed desert specialist plants
like these Lithops,
aptly nicknamed living rocks.
Living close to the ground,
these plants aren't exposed to the drying winds.
There's not much of the plant above ground,
but to help their few leaves
gather enough sun for photosynthesis,
their surface is see-through.
They're succulents, storing water in their chunky leaves.
Despite the tough conditions,
the plants can be hardy and long-lived.
The Welwitschia, sometimes called a living fossil,
is only found in the Namib Desert.
But despite this hostile environment,
individuals survive for thousands of years.
(insects chirping)
All the plants are living water stores
for a surprising wealth of wildlife.
Gemsbok, like many of the animals here,
have adapted to survive
without access to water for weeks on end.
(gentle music)
They get what they need from the plants.
To conserve this most precious desert resource,
they don't sweat to cool down,
instead allowing themselves to overheat.
Their bodies can reach 45 degrees centigrade,
which is hot enough to cause brain damage in most animals.
But they cope thanks to a network of blood vessels
that carry the excess heat away from their brain.
There's not a huge diversity of large animals here.
The desert is too tough for most.
But the gemsbok are joined by ostrich.
Springbok.
And a few zebra.
(zebras thumping)
Giraffes even manage to make a living here.
They can only cope where there are enough acacia trees.
Their long highly-mobile lips
help them pick out tiny leaves
from between the plant's thorny defenses.
The giant trees seem to live in the absence of water,
but the desert can deceive.
While the Namib lacks any surface water,
there are rivers that run deep underground,
and along their course the trees are able to make a living
using exceptionally long roots to boar down into the ground
and extract moisture.
(elephant trumpets)
Thanks to their efforts,
other animals get a little moisture from their leaves.
It's even enough to sustain the biggest animals on Earth.
And the trees form the rare luxury of cool shadows
that creatures of all sizes can enjoy.
Plants really define the success of whole food chains
and they are masters at adaptation.
The plants vary just as much as the animals
from one region to the next.
(bird craws)
North America has four main deserts.
The Great Basin is high elevation,
meaning that it gets harsh winters.
(gentle music)
Rather than rain,
the little moisture it receives falls as snow.
The plants here are not succulents.
Instead, they are dominated
by the small-leafed and hardy sagebrush.
The tough plants are enough to sustain
one of the larger desert animals.
Pronghorns.
Almost all of their water
comes from the leaves of these tough plants.
Often called antilope,
the graceful creatures are the last members
of a unique family of fleet-footed grazers.
For their cold desert home, they need a thick coat,
but at the same time must cope with extreme heat,
so they can rise the hair on their backs,
allowing hot air to escape.
(gentle music)
There are few trees out here on the plains,
the usual places for birds to nest.
But burrowing owls live up to their name,
raising their families underground.
It also gives them a place
to escape the fierce desert temperatures.
While most of North America's deserts get harsh winters,
the Sonoran does not.
Hot year round,
the Sonoran straddles five US states
and a chunk of Northwestern Mexico.
Over 200,000 square kilometers of heat
dominated by the most unique
and iconic desert plants, cactus.
With nearly 2,000 species,
these hardy plants can range from minute to mega.
Up to 20 meters tall,
they are living water towers.
(thunder booms)
(cactus thuds)
Up to 90% of their weight can be the water stored within.
Though some have long tap roots
to reach deep water sources,
most have very shallow but wide-spanning roots
close to the surface
to soak up any rain that falls before it can evaporate.
(gentle music) (rain whooshing)
Their thick waxy skins can reflect the sun
and seal the surface of their leaves to reduce water loss.
Because water is stored in their leaves
and water is the most sought-after resource in the desert,
the cacti need to defend themselves,
otherwise every animal would be raiding their supplies.
(bright music)
So their soupy water inside is bitter to deter drinkers,
though most never get through the first line of defense.
Their famous spines are actually
the plants' highly-modified leaves.
Having normal leaves would increase the surface area
of the plant
and the amount of water lost to evaporation.
Small hair-like spines can also trap a layer of air
close to the plant's skin,
creating a microclimate above her
against the extreme heat of the day and cold of the night.
(squirrel munching)
(gentle music) Like most plants,
the cactus photosynthesize to produce food,
which involves the intake of carbon dioxide
and the output of oxygen.
Plants have stomata,
little breathing holes all over their skin,
for this gas exchange to take place.
But cacti keep their stomata closed during the day,
opening only at night to let out oxygen
and take in carbon dioxide
which is then stored until the sun comes out
and photosynthesis can take place.
(insects chirping)
Thanks to this unusual nocturnal behavior,
cactus can reduce water loss through these pores by 90%.
(animal screeching)
It's not just plants making the most of the cool night.
Not a werewolf howling at the moon.
In fact, not a very threatening-looking creature at all.
But the grasshopper mouse is a predator through and through,
and its quarry some of the most poisonous creatures
that inhabit the desert.
(tense music)
It has a powerful bite to snip off the scorpion's weapons.
But also a resistance to the arachnid's usual lethal venom.
In the Sonoran Desert of North America,
in the ankle-high animal community,
the grasshopper mouse reigns supreme.
(dramatic music)
(mouse screeching)
(insects chirping)
A barking gecko out strolling in the dark African desert
is a bit alarmed by his neighbor.
(gentle music)
Though he might occasionally nibble a little lizard,
the porcupine would much prefer a plate of greens.
He's one of the biggest rodents in the world
and well-armed against the many large predators
of the African bush.
But he's not so well-protected against the desert sun,
so when the sun begins to rise,
he'll head back to his burrow.
Some of his neighbors have the opposite strategy.
Meerkats are not built for cold temperatures
and huddle through the night in burrows.
(gentle music)
When the sun rises, they head out to greet it.
Most mammals maintain even temperature at all times,
but meerkats allow their bodies
to warm during the day and cool during the night.
To help them bounce back from their chilly slumber,
the family sunbathes.
As it gets hotter,
they will take the baking temperatures in their stride,
foraging for breakfast.
The real treat this morning,
like the grasshopper mouse,
meerkats are scorpion slayers.
(meerkats screeching)
The ground squirrels that live alongside them
need a little bit of help in the heat.
(gentle music)
(squirrel munching)
They raise their tails, built-in parasols,
to offer a bit of portable shade.
(squirrel munching)
They have another way to chill when the going gets tough.
They dig to expose cooler sand beneath the surface.
Then they can lay back and enjoy.
In her Eurasian desert,
the long-eared hedgehog is out and about.
She ignores the herds of delicate gazelles.
They can cope with extreme temperatures
but prefer to get most of their hard work done
before things heat up.
Dawn is the best time for the hedgehog to forage.
It's when most animals are active,
before the day gets too hot.
This time, she gets lucky.
There is just enough food to sustain her little body.
(gentle music)
Big animals are scarce in the desert.
Few have what it takes to cope
with the huge shifts in temperature
and the lack of water.
Apart from the most iconic desert giant, the camel.
With tough mouths to cope with the dry vegetation,
long eyelashes and closable nostrils
to keep out the ever-blowing sands.
The ability not to lose much water through sweat or urine.
Broad feet to spread their weight on sandy dunes.
And of course their most famous humps,
fat stores that can be broken down to water and energy
when they fall on hard times.
Dromedary camels like these
once roamed across much of North Africa and Western Asia,
but for the last 2,000 years
they have been extinct in the wild.
And that's because of a unique relationship
that formed some 4,000 years ago.
The camel was domesticated.
While wild cousins were hunted or interbred
with the domestic animal,
the captive herds grew to take their place.
They made it much easier for another species of large mammal
to make a living here.
(fire crackling)
Humans.
(water sloshing)
There are a number of human populations
who have adapted to desert life,
such as the Bedouins.
A nomadic lifestyle has enabled these people
to exploit the desert,
keeping their animal herds on the move
so they don't overgraze what little vegetation there is.
(gentle music)
Most deserts have indigenous people
who have adapted to the challenging terrain.
The San people,
once known as the Kalahari Bushmen,
have inhabited Southern Africa for at least 20,000 years.
From their Stone Age ancestors,
they maintain a nomadic desert lifestyle in the Kalahari,
using an intimate knowledge of the landscape
and its plants and animals to find everything they need.
(water sloshing)
They use the poisons of plants and insects
to make lethal spears
and track their quarry until the poisons bring it down.
(dramatic music)
The cultural identity of the San faces extinction
in the light of modernization and globalization.
But there is another threat
not only to their way of life,
but to deserts and to the world.
(traffic rumbling)
The massive expansion of the human population
over the last few hundred years,
and especially its industrialization,
has changed the planet's atmosphere.
Carbon and other gases
added to the air through the burning of fossil fuels
acts as a blanket,
trapping heat from the sun
(gentle music)
and making Earth warmer.
And that's not all.
For fuel, building materials,
and to clear space for livestock,
the growing human population has cut trees,
taking away the shade they provided
and their roots that bound the soil.
(trees crackling)
(birds cawing)
(sheep bleat)
Too much livestock is being put on the land.
Overgrazing destroying the plant life.
And intensive farming has reduced the fertility of soil.
These, combined with climate change,
can alter fertile landscapes and turn them to desert.
It is believed the Sahara has grown by 10%
in the past 100 years.
And all deserts continue to grow to this day.
(gentle music)
4,000 years ago,
the Sahara was a lush, green, and productive landscape.
It only took a tiny wobble of the Earth's axes
and a minute temperature change
to produce desert.
A reminder of how quickly and how drastically
habitats across the world could change.
And it's a self-fulfilling cycle.
The desertification of land leads to more crop failures,
more erosion, famine, and drought.
(tense music)
Millions of people are already impacted.
(hatchet clinking)
In fact, 1/6 of the world's population lives in desert,
and their lives are at risk.
Though there are many ways to fight the problem,
using desert hardy crops that can enrich the soil.
(uplifting music)
Careful water management and irrigation
to use water sustainably.
And perhaps most of all planting trees to act as windbreaks,
stabilizing and shading the soil.
Reducing the ground temperature.
Desert has great potential for wind and solar farms
to produce renewable energy.
In fact, it's thought covering just 1% of the Sahara
in solar panels
would provide enough energy for the whole world.
♪ Wooo ♪
And an ambitious project
is building a wall of trees across the Southern Sahara
that will be the largest living structure on the planet,
8,000 kilometers long,
which is already improving the health and livelihoods
of the people living around it.
♪ Ooo ♪
♪ Wooo ♪
Deserts don't have to be bad.
They are beautiful and important habitats
for unique plant and animal species.
But they are fragile and need protecting
to continue their magic.
(gentle music)
And now the desert has a final surprise in store.
One of the defining features of deserts
is low unpredictable rainfall.
(rain dropping)
Because of it,
plants and animals can lie dormant in the ground
and can live their lifestyles quickly
because they know that sooner or later
the most precious of resources will come.
(thunder booming)
(rain whooshing)
It only takes a few drops
and then seemingly in the blinking of an eye
the desert is transformed.
A rainbow carpet of flowers,
a phenomenon that can spring up in deserts across the world.
These extraordinary plants use color and fragrance
to attract insects to pollinate them as quickly as possible.
They will soon produce fruit and seeds
so that as the ground dries up
they can wither away and lie dormant in the soils
until the rains return.
During their glorious showdown,
the animals of the desert get a rare respite.
A brief time of plenty.
They can enjoy rare generosity from the desert.
And raise their young on the bounty.
Some, like the elegant demoiselle cranes,
travel to be here and rear chicks while the going's good.
And for the year-round residents,
there are insects in abundance.
And the hedgehog can feast.
(gentle music continues)
Which is just as well.
In her den, this female has become a mother.
The rains have brought a much needed boost
that will help her raise her little ones,
preparing them as the next generation of desert survivors.
(gentle music)
(wind whooshing)