Vast open plains.
Immense spaces.
Eerie silence but any feeling of emptiness is an illusion.
The plains of our planet support the greatest gatherings
of wildlife on Earth. At the heart of all that happens here
is a single living thing.
Grass.
This miraculous plant covers a quarter of all the lands of the Earth.
Grasslands exist
where ever there is a little rain, but not enough to sustain the forests.
Some are huge. The Central Asian Steppe alone extends one third of the way
around our planet.
It's summer and eagles effortlessly cruise the thermals
scanning the ground beneath for signs of prey.
In the distant reaches of Outer Mongolia one of the planet's great migrations
is underway. Few people ever see this extraordinary annual event.
Mongolian gazelle.
Two million are thought to live here but no one really knows.For much of the time they're scattered through this vast landscape
but once a year they come together to have their young.
Nearly all will give birth within the next ten days.
Out in the open, communal calving is the safest way to have young.
With so many pairs of eyes keeping watch
it's almost impossible for predators to sneak up.
There are no bushes, no trees, there's only one thing to hide behind,
grass and it's not very effective.
Predators also have a hard time raising their young on open grassland.
Without trees eagles have to nest directly on the ground.
All inhabitants of the Great Plains are exposed to the elements.
Fire sparks panic in the herd.
Gazelles are born to run, and even young calves easily outpace the flames
if they can avoid being trampled.
With nothing to stand in it's way the blaze consumes anything that can't flee.
Huge quantities of grass, valuable food have been lost
and with it the old and the weak.
The gazelles move on to new pastures and leave the desolation behind them.
From the ashes rises the phoenix. Grass the incredible survivor.
Because it grows from a protected part at the base of its stems, grass is almost indestructible.
Able to repair and reproduce itself rapidly
it covers more of the Earth's land than any other plant and feeds more wildlife than any other.
Red billed quelea.
One and a half billion swarm across the savannas of Africa.
These are the most numerous birds on Earth.
Some flocks are so vast, that they could take five hours to pass overhead.
Only grass can feed plagues of these proportions.
The ravenous hordes devour the seeds and the leaves and stems are cropped
by great herds of antelope.
The East African savannas alone sustain nearly two million wildebeest.
They trim the grass down to it's roots leaving little in their wake
but within days the plant will recover and continue to sustain
the biggest herds on Earth.
Grass is not confined to the tropics.
It manages to grow even in the bitter conditions of the Arctic.
Beyond the limits of the last tree the planet is barren and ice locked.
The frozen no man's land at the end of the Earth.
But, for a short time each year, the long dark winter releases it's grip.
Temperatures rise, and grass that has lain dormant and frozen throughout the winter
sprouts once more. Green returns to the Arctic.
The receding ice reveals an immense flat plain, the size of Australia.
This is the Arctic tundra.Snow geese.
They winter along the Gulf of Mexico and in spring they fly the entire length
of North America to reach the Arctic tundra.
Five million birds make this journey every year.
Their marathon migration is almost three thousand miles long
and has taken them three months.
Exhausted and starving, they touch down inside the Arctic Circle
back at their traditional breeding grounds, at last.
Snow geese pair for life.
As soon as couples arrive, they must stake a claim to a nesting patch.
Ideal sites are in short supply and quarrelsome neighbors are all around.
Disputes can be vicious.
Point taken.
It's a long way to travel, but for a short period the tundra is the ideal place for a grazer.
The grass grows vigorously during the short intense summer
and the are fewer predators than farther south.
Here, geese can nest on the ground in relative safety nonetheless this female must
incubate her eggs for three weeks and throughout this time
she will be very vulnerable.
An Arctic fox surveys the colony.
She's been waiting for the geese all winter.
Sneaking up unnoticed is impossible. Perhaps fortune will favor the bold.
The colony is well defended. There are no easy pickings here.
She's driven away from every nest, but hunger compels her to continue.
There are more eggs here than she can possibly eat now
but the nesting season is short so she stashes much of her plunder
for later in the year
when all the geese have gone.
Further south, other bigger predators prowl the tundra.
Wolves.
For them, finding food on the plains is an even greater challenge.
Not only is their prey seasonal it's also hard to find.
They've been searching for days without a sign.
Somewhere in this immense landscape there is food for them.
This is it.
Caribou.
Travelling thirty miles a day they can cover nearly two thousand miles
during the summer months. The wolves will starve if they don't find the caribou
but it's no easy task to locate prey that never stops traveling.
Biting flies and the quest for new pasture drives the migration ever onwards.
The prairies of North America.
This rich pasture once supported the greatest herds ever seen on our planet.
There were once sixty million bison
but no animal is immune to intensive hunting by man or the destruction of it's habitat
and a century ago the bison were reduced to barely a thousand.
Now, thanks to rigorous protection, the species is recovering.
The growing season is long and the grass here can support herds all year around.
Male bison weigh in at one ton. In high summer the bulls are fat from the rich grazing
and in prime condition but only a few will mate.
Exactly which few is about to be decided.
On temperate plains around the world summer is a time for growth and reproduction.
Now the grass produces it's flowers. New colors also come to the plains.
The northern flowering is mirrored by the grasslands of the southern hemisphere.
And nowhere is more impressive than on the velt of South Africa.
Not all temperate plains are so rich and colorful in the summer.
This is midsummer on the Tibetan Plateau the highest great plain in the world.
Despite the conditions, grass survives, and in sufficient quantities
to support the highest of all grazing herds those of the wild yak.
Even in summer life is hard temperatures rarely rise above freezing,
and the air is thin.
It's also exceptionally dry
for one very big reason the Himalayas.
The great mountain range acts as a barrier preventing clouds moving in from the south
and this casts a giant rain shadow that leaves Tibet high and dry.
Grass clings to life even as desiccating winds remove what little moisture remains in the soil.
So long as grass can survive, so can grazers.
Female asses are mysterious creatures.
They come and go as they please and much of their behavior seems unfathomable to an outsider.
They're the great nomads of the plateau and will often trek vast distances across these
parched plains in search of oases.
But when they do find paradise they're liable to feed and drink
for just a few hours and then head back to the dust
for no apparent reason.
Wild ass are the most conspicuous pioneers of this high frontier
but the most numerous grazer in Tibet lives underground.
Pika
A relative of the rabbit. It too feeds on grass.
On the exposed plateau pikas never stray far from their burrows but even so, squatters will move in
given half a chance.
While ground peckers and snow finches can be a nuisance
they're worth tolerating,because they provide a valuable early warning system.
The bizarre Tibetan fox. The pika's nemesis.
When stalking, it keeps below the skyline perhaps helped by it's curious body shape.
But why the square head? In summer, the Tibetan plateau heats up
drawing in warm wet air from the south but the water never arrives.
As the moist air approaches it's forced upwards by the Himalayas
and condenses into huge rain clouds.
These clouds drop all their water on the southern side of the mountains.
The very peaks that keep Tibet dry are responsible for the monsoon rains
falling farther south, and the greening of India.
Here, soaked by rain and bathed in tropical sun grass reaches it's full potential.
Elephant grass is the tallest in the world. Grass that towers over an elephant,
can conceal all sorts of surprises. On the African savannas, grazers are marching
in search of grass and water.
A few African savannas are very special. Here, rain water from far and wide
flows across the flat plains. Grass is submerged but still it grows.
Flooded, burnt, baked and frozen grass can withstand it all.
After six months of drought, grass replaces dust over great areas.
Fresh new shoots draw animals from great distances.
Many undertake epic migrations to catch the boom time.
Some resourceful animals live here all the year round.
Baboons are permanent residents but they have to change their behavior
if they are to gather what they need on the newly flooded plains.
There's plenty to eat but getting to it can be a little uncomfortable.
New water poses problems for the youngsters but they know where to find a dry seat.
A juicy snail is ample recompense for sodden paws.
Having survived the dry barren times animals can now reap the rewards.
On this seasonal planet, the great plains are lands of feast and famine.
At their peak they support the greatest gatherings of wildlife
found anywhere on Earth.
