Wild Asia: The Arid Heart

The arid lands of Asia - lands of contradiction.

The sandy deserts of India are separated

from the parched interior by the mighty Himalayas.

In their rainshadow lie the deserts

and dry grasslands of China and Mongolia.

The stony Gobi Desert is further

from the sea than any place on earth.

Fierce summers are followed by bitter winters.

North of the Gobi on the grasslands of the Mongolian steppe,

temperatures can plunge to minus fifty degrees.

Like the nomads and their domestic horses,

the wild animals are tough and resilient.

They thrive in the extremes of Asia's ARID HEART.

The long winter is ending on the steppe grasslands,

home to a wild animal the Mongolians know as takhi - the spirits.

Westerners call them Przewalski's horses.

They're the only true wild horses in the world.

The seven mares of this herd are pregnant.

Their foals will be born in a month or two,

in the short summer,

when they'll have the best chance of survival.

Takhi are distinguished by short upright manes

and stripes on the backs of their legs.

They're closely related to the ancestors of domestic horses,

but takhi have never been tamed.

The Mongolians have named the stallion of this herd Khan —

aft their famous ancestor Genghis Khan.

In the 1 3th century Genghis Khan rode out from here

to create the largest empire the world has ever seen.

The Mongol Empire spanned 8,000 kilometres of grasslands

stretching across Asia into Europe.

Like the takhi and Mongolian gazelles,

Genghis Khan and his warrior tribes were nomads,

constantly on the move in search of good grazing.

Mongolia remains a sparsely-populated land

of nomadic herders.

For countless generations the nomads

and their herds have lived

alongside the wildlife of the steppe.

To the herders,

demoiselle cranes are symbols of good fortune;

to harm them would bring bad luck.

The cranes have their own strategy

for surviving the extremes of the steppe.

They escape every winter,

and return in spring to re-establish breeding territories.

The arrival of a male joining his mate

ruffles territorial feathers.

During the breeding season each pair defends

an exclusive territory a few hundred metres across,

to ensure they get the food and water

they'Il need to raise a family.

Once they've agreed on boundaries,

the couples turn their attention to each other.

Cranes are long-lived, and often pair for life.

Before they breed they renew their bonds

in a demoiselle's pas de deux.

Like all demoiselle cranes,

this pair have returned to breed

in the valley where they were born.

To get back from their wintering grounds in lndia,

they have flown 3,000 km over the Himalayas.

The final leg of this astonishing journey

was across the Gobi Desert —

the bleak centre of Asia's arid heart.

Gobi means "stony".

Strong winds have stripped the soil,

leaving only stones,

polished to a shine by the fierce heat.

There's very little water —

at the puddles that pass for waterholes animals

often have to dig to find moisture.

As summer temperatures soar to 50 degrees,

any water soon evaporates,

leaving only soda crystals.

The desolate Gobi is home to the world's only wild camels —

the bactrian camels.

Little more than a thousand of these two-humped nomads remain,

roaming the deserts between China and Mongolia.

Two females and their month old calves

have joined forces to be safer from predators such as wolves.

Camels are superbly adapted to the desert.

Bushy eyebrows and double lashes protect their eyes from sand,

and they can cIamp their noses tight to keep out dust.

Soft padded soles stop their feet sinking into sand.

Camels can go for up to ten days without water.

Their humps hold reserves of fat to sustain them

while they wander the desert in search of food.

The females are shedding their thick winter coats.

The summer ahead will be short,

but intensely hot.

Great gerbils have a different strategy for surviving the desert's

extremes - they go underground.

The uneven surface of their colony conceals

an extensive network of burrows

that provide shelter from winter cold and summer heat.

The first litter of the year has just ventured above ground.

They sniff each other constantly for the reassuring smell of family.

Great gerbils are one of many rodents who've adapted to the desert.

They get all the moisture they need from plants.

But even the best-adapted desert shrub depends on occasional,

unpredictable rain.

Rain might fall on some parts of the desert and not others.

If it comes,

it's a blessing.

In most years only 50 mm of rain falls,

most of it in summer.

Desert plants can wait a whole year for a single shower.

When it comes they respond rapidly.

But almost as quickly as water appears,

the desert air sucks it away.

A strange parasitic flower steals water and nutrients

from the roots of desert shrubs

enjoying a growth spurt after the rain.

But its bright flowers won't last long in the drying wind.

During the day,

beetles write their signature in the sand.

But other tracks belong to animals

that come out only in the cool of night.

The hairy-footed jerboa is a relative of the larger great gerbils.

Also known as a kangaroo rat,

the jerboa leads a solitary life.

It's much more adventurous than the great gerbils,

and may travel more than 2 km a night to find food.

It's a skilled digger,

busiest just before dawn.

In only ten minutes a jerboa can dig a hole half a metre long,

where it will hide from the heat of the coming day.

Great gerbils are also good diggers.

By continually living and burrowing in one place

they reshape the environment to suit their needs.

They're like gardeners - turning the earth,

fertilising it with their waste,

and living off the plants it nurtures.

Their gardening strategy has stood the test of time.

Although each gerbil only lives for two to four years,

some of their colonies are centuries old.

Gerbils are great hoarders —

they stockpile in spring in case there's a summer drought,

and in autumn they accumulate for winter.

They spend long periods

cropping the lush salsola bushes which flourish

because of the pruning and manuring they get from the gerbils.

The youngsters grow quickly and soon

learn to harvest for themselves.

They must also learn to keep an eye out for danger.

A quick retreat foils the black kite,

who continues to hunt,

scanning the desert with sharp eyes.

A female buzzard hovers above her nest,

as her paler mate delivers his catch.

He's left a voIe which she shares between their chicks.

Birds of prey are feared by all small desert animals.

A vole spends as little time as possible above ground.

A Iizard relies on camouflage and stealth. . .

. . .which sometimes isn't enough.

A luckless lizard is lunch for the buzzard chicks.

The male buzzard will be a constant presence in the summer sky

as he hunts for his growing family.

Summer starts later on the more northerly steppe,

where the demoiselle cranes are just beginning their family.

Their nest is a simple scrape of pebbles in short grass.

When the female returns from feeding

she rolls her egg before settling.

She'll incubate the egg for a month,

while her mate patrols their territory.

Cranes raise just one or two chicks a year.

As the herders move their horses to and from water each day,

the female sits tight on her precious egg.

Khan and his herd are feeding

on lush summer grass by a small river.

Five takhi foals have been born in the previous month.

They boost the numbers in Khan's herd to eighteen.

Life seems idyllic, but it hasn't always been easy.

In 1 968,

Przewalski's horses were driven to extinction in the wild.

Since the early 1 990's

animals bred in zoos have been released in areas such as here,

in Hustain Nuruu National Park,

now home to more than a hundred wild takhi.

Khan is the dominant stallion

in a herd of seven mares and their offspring.

There's a cIear hierarchy within the group.

But there are also strong bonds between individuals,

which they reinforce by mutual grooming.

A low ranking horse who tries to join in is chased off.

The last mare to give birth is coming into heat.

Khan and some of the young stallions cluster round

to see if she's ready to mate.

Khan's sniffing tells him she's not yet ready.

The mare lashes out at the unwanted attention.

Khan leaves.

When he judges the time is right

he'll chase the youngsters away.

Domestic cows have also been attracted to the rich grazing.

Khan considers them a threat.

Cattle compete for food,

but it's Mongolia's three million domestic horses

that pose the greatest threat to the takhi's long term survival.

The two species have different numbers of chromosomes,