One quarter of all the land on Earth
is covered by a single, remarkable type of plant.
Almost indestructible, it can grow two feet in a day...
And be tall enough to hide a giant.
That plant is grass,
and the world it creates is truly unique.
The grass in northern India is the tallest on the planet,
home to some of the most impressive creatures to tread the Earth.
These are the good times,
but in just a few months, all this fresh growth will be gone,
and the animals will be forced to move on.
That is the way things are on grasslands across the planet.
A cycle of abundance, destruction and rebirth
that affects every creature that lives here.
The largest grassland on Earth, the vast Eurasian Steppe,
stretches one third of the way around our planet.
Spring rain has brought fresh grass, and with it, new life.
A relic from the Ice Age, a baby Saiga antelope,
just three hours old.
His only company, his twin.
Until they can stand, their mother has left them hidden in the grass.
They should be safe, as long as they remain quiet.
For these calves, the clock is already ticking.
Their herd will soon be moving on, seeking the freshest new grass.
Their lanky legs are a sure sign that they're built for a life on the move.
Saiga always give birth to twins,
so their numbers grow rapidly just when grass is plentiful.
Their bizarrely shaped nose can detect fresh growth
from hundreds of miles away.
The young twins will now begin the nomadic life
they share with most animals on the world's open plains.
Grasslands occur where rain is too sporadic for forests to exist.
The rain that a grassland needs to survive for a year
might arrive all at once.
Storms like these can release 12 inches of rain in 24 hours.
Not much fun if you're out in it.
Eventually the earth can't soak up any more,
and the grassland undergoes a radical change.
Many plants would drown here, but grasses thrive.
They grow so fast,
their leaves quickly rise above the water and into the sunlight.
Here in southern Africa,
water transforms one of the most remarkable grasslands on Earth,
the Okavango.
Every year, 5, 000 square miles of grassland are flooded.
For one pride of lions, this poses a major problem.
There may be plenty of prey around,
but lions struggle to run it down in water.
The pride has three-month-old cubs. They've never seen water before.
If their mothers don't make a kill soon,
the cubs might not survive the week.
But fuelled by the flood, the eruption of grass attracts new possible prey.
Buffalo arrive in herds 2, 000 strong.
Powerful, aggressive and united,
they're the most dangerous animal a lion can face.
The biggest bulls don't run.
They're simply too huge to be scared of lions.
At 900 kilos, he weighs more than all five lionesses combined.
The pride do have numbers on their side,
but one sweep of his horns could be deadly.
One distracts the bull up front, while her sisters attack from behind.
The cats must somehow topple the buffalo,
but with swamp under foot, they can't get any traction.
The bull is weakening,
but the lions are tiring, too.
It's now a battle of will as much as strength.
To live, the bull must somehow shake off the lioness.
The bull is wounded,
but thanks to his two-inch-thick hide, he will recover.
For the pride, these are hungry times.
But, ultimately, once the water recedes, there will be new life,
and new food to benefit all.
In the right conditions, grasses have the extraordinary ability
to grow from first shoots to flower in a matter of only days.
Grasses become the miniature equivalents of fruiting trees.
And for creatures living within the grass,
this is a landscape as vast and towering as any rainforest.
And excellent place to build a tiny tree house
for a harvest mouse.
During summer, European meadowlands are full of food,
but only for those that can reach it.
Climbing grass is harder than climbing trees,
not least because their stems just won't stay still.
Her prehensile tail acts like a fifth limb,
so she's as agile as a monkey clambering around in a tree.
And just as well,
for the best food in this tiny forest is at the very top of its canopy.
Feeding up here, she's exposed.
A barn owl.
Not her finest move...
But it did the trick.
Harvest mice seldom go all the way down to the ground.
It's a tangled and dangerous world down here.
But she can read the pattern of the stems overhead like a map,
and so find her way home.
And not a minute too soon.
There are mouths to feed.
Her babies must fatten up quickly.
They need to harvest the summer grasses while they're still rich with food.
On the African savannah, too, seasonal grasses are filled with life,
but it won't last long.
Carmine bee-eaters are superb aerial hunters,
experts at catching insects in midair.
But they have no way of flushing their prey out of the grass.
Once alarmed, most insects stay put.
The bee-eaters need someone to stir things up a bit.
A kori bustard.
It's the world's heaviest flying bird,
so it should be bulky enough to kick up some insects.
Bingo!
Until someone else comes along and cramps your style.
Never mind, perhaps there are bigger opportunities ahead.
What about an ostrich?
The heaviest bird of all.
This time there's more than enough transport to go around.
Soon, almost every ostrich has its own passenger.
But free riders are only tolerated for so long.
What the bee-eaters really need
is a creature so big it won't even notice them.
Nothing cuts a swathe through grass like an African bull elephant.
The trick is to fly as close to the front of the giant as possible.
They only have a split second to grab the prize.
As more insects are stirred up, the competition intensifies.
With summer drawing to a close, the race to stock up is on.
Soon, the grass will wither, and this opportunity will have gone.
As the dry season takes hold,
food becomes increasingly thin on the ground.
Now, only the most specialised predators on the plains can make a living.
She may be spotted like a cheetah, but this cat is no sprinter.
Instead, she has extra-long legs which give her a high vantage point.
But a serval cat's main weapon are enormous radar ears.
They help her pinpoint prey hiding in the grass.
But the prey she seeks are canny.
Southern vlei rats.
They know that any sustained movement can give them away.
So they move in short bursts.
But even the slightest rustle will give her a clue.
Warm.
Warmer.
Missed.
In better times, she could catch 10 a day,
but now, with so few rodents around, she will have to go hungry.
As drought intensifies, life gets tougher for all.
Predators with permanent territories must tough it out,
while most of their prey disappear over the horizon.
To avoid starvation, many grassland animals follow a nomadic way of life.
Over 2, 000, 000 wildebeests wander the East African savannahs
chasing the rains.
And they are not alone.
Arriving on the wing,
Jackson's Widowbirds also seek fresh grass.
Although, it's not just food that they're after.
This male wants a mate.
He's grown elaborate breeding plumage for this moment,
but he needs a stage on which to show it off.
By carefully selecting grass blades, each trimmed to the correct length,
he's creating something very special.
He needs an even surface,
and a centre-piece.
The stage is set.
His bachelor pad is sufficiently neat and tidy to attract a female.
The problem is,
can she see it?
He has competition.
It might take more than a little gardening to impress the ladies.
Jumping is the right idea,
but he's misjudged the height of the grass.
His rival makes it look easy.
Time to raise his game.
It's not only who jumps the highest, but who can keep doing so the longest.
Unable to go the distance, his rivals drop out one by one.
Stamina has won him admirers,
now he can show off his courtship arena...
And engage in a little romantic hide-and-seek.
Finally, he's done enough.
The East African savannahs support millions of grazers.
Each year they devour millions of tons of grass,
and yet there's one creature here
whose impact is far greater than all these animals combined.
They're found wherever grass grows on the planet,
yet their labours go almost entirely unnoticed.
One of the most remarkable is found here on the grasslands of South America.
These blades are so tough that virtually no large grass eaters can stomach them.
Yet they're harvested on an industrial scale...
...by tiny grass cutter ants.
But they themselves can't digest one bit of it.
So, why bother?
The answer is underground,
and it's very ingenious.
Each blade is cut to length and placed into a garden of fungus.
The rotting grass feeds the fungus, and in turn the fungus feeds the ants.
But feeding 5, 000, 000 workers requires intensive agriculture.
Luckily, they are an industrious lot.
This colony alone will collect over half a ton of grass every year.
With billions of ant colonies across the world's grasslands
all doing exactly the same thing, that's a mind-boggling amount of grass.
It's estimated that over one third of the grass that grows on Earth
will be harvested by an insect.
In northern Australia, termites memorialise their industry in sculpture.
These astonishing mounds are 10 feet tall.
They're always built on a north-south axis,
which is why their builders are called compass termites.
These castles of clay
protect their builders from extremes of heat
and seasonal floods experienced on many grasslands.
Termites manage to do what most grass eaters can't,
break down dead grass and extract the nutrients.
But they themselves can be food for those that can reach them.
A two-foot-long tongue
covered in microscopic hooks,
followed by claws longer than those of a velociraptor.
A giant anteater on the plains of South America.
It can devour 20, 000 insects a day.
Powerful forelegs enable it to rip apart a termite hill with ease.
And as the sun bakes the grass, the termites face new danger.
In minutes, fire turns grassland to ash.
But the grasses are not dead. Their underground stems are unharmed.
Weeks, months may pass,
but eventually the rains will return and the grass will sprout again.
Some grasslands must endure not only fire, but ice.
As winter approaches, the prairies of North America begin to freeze.
In summer, bison roamed freely,
almost continuously cropping the abundant green grass.
Now, that grass is not only withered and frozen, it's about to be buried.
Sixty million tons of snow now blanket this herd's territory.
Pushing through deep snow is exhausting work,
and the bison are now slowly starving.
Just keeping warm saps huge amounts of energy.
Their thick coats can insulate them down to minus 20 Fahrenheit.
It's now minus 40.
The only thing that will keep them alive is buried beneath three feet of snow.
And that's a problem shared with a surprising neighbour.
The food the fox seeks is also deep beneath the snow.
The survival of both creatures depends on getting through to the ground.
For the bison, it will be a matter of brute strength.
Massive neck muscles enable them to shovel five tonnes of snow a day.
Their light-weight neighbour needs more precision.
The bison have reached their goal,
a mouthful of withered grass.
And where the bison have dug, the fox now spots an opportunity.
Every footstep counts,
but he mustn't break through...
Yet.
He listens carefully to pinpoint his target.
It's moving.
A vole.
Small, but 100 times more nutritious than a mouthful of dried grass.
To get through the winter on these prairies, sometimes brain beats brawn.
Ultimately, life on all grasslands depends on the turn of the seasons.
Five hundred miles further north than any tree can survive,
grass returns to life.
Caribou females have journeyed to the far north
to calve.
Over 70, 000 caribou babies will be born in the next few days.
As the calves appear, so too do the leaves of the newly sprouting grass.
And the calves must strengthen quickly.
Within days they will have to keep up with their parents
on a never-ending march.
At one day old, they're already faster than an Olympic sprinter.
They're testing the legs that will carry them thousands of miles,
better to learn their limitations now.
It may look playful, but there's no harder life on the grasslands
than that facing these infants.
The caribou mothers now join together,
each with an infant exactly the same age.
They're setting off on the greatest overland trek made by any animal.
But wherever grass eaters travel, predators lie in wait.
Here they are, Arctic wolves.
They must seize their chance
while the caribou pass through their territory.
The wolf runs at the herd, trying to flush out the weak or the slow.
A calf is separated.
At full tilt, 40 miles an hour, the wolf is just faster.
But the calf has stamina.
Only a few weeks old, and this calf's will to survive is remarkable.
And it needs to be,
for these young caribou have now started a journey
that will last a lifetime.
Forever chasing the seasonal growth of the grass on which they depend.
Like all grassland creatures, they are at the mercy
of these unpredictable but ultimately bountiful lands.
Grass can survive some of the harshest conditions on Earth,
flood, fire and frost, and still flourish.
So it is that grasslands provide a stage
for the greatest gatherings of wildlife on planet Earth.
For the grasslands team, no location would prove as challenging
as that dominated by elephant grass in northeast India.
The aim, to capture intimate images of some the world's most elusive creatures
using the latest technology.
But they will need to be careful.
More people are killed by wildlife here in Kaziranga
than in any other national park on the planet.
Every time we go into these tunnels,
we have to take an armed guard,
'cause there are so many animals in here that are dangerous.
Tigers are probably the least of our worries,
but rhinos and buffalo,
elephants, sloth bear, all of them can injure you.
And we gotta keep up with our armed guard.
The team have bumped into their first obstacle.
There's a rhino right there.
Let's go back because it's too risky going through this heavy grass.
Let's get in the open.
There's another rhino.
- Now we have two rhinos. - Let's get in here.
Okay.
The guard throws a ball of mud to one side of the rhinos,
moving the animals on without harming them.
- We're okay. It's gone. - Okay.
What about the other one?
Let's go, quick.
With the rhinos now a safe distance away,
the crew focus on the best spots to position their camera traps.
I love that tunnel, the effect.
Over 100 scaffold poles provide the anchor points
for these secret cameras.
When an animal triggers an infrared beam,
the cameras will switch on automatically and start recording.
If it works, the remote-control cameras should capture close-up footage
without disturbing the animals or putting the crew at risk.
Basically, that's about as much like grass as we can make it look.
As night falls, the crew head back to base for safety.
It's time for the new technology to prove its worth.
At dawn, the crew have a whodunnit mystery on their hands.
Oh, wow.
That's carnage!
This looks like elephant, we think?
This is scaffold pole
they have bent. Look at that.
It's a sad day. You win some, you lose some.
And this time, the animals have outsmarted us.
In fact, check this out.
Whoo-hoo.
So this is our little army of guards, protecting our trigger box.
Do they bite? These ones, they bite?
Sting?
Whoa! Argh! Ow!
The little.
While Chadden irons out the bugs,
Sandesh has met some grumpy locals.
Wild Asian water buffalo have extraordinary senses.
Mothers will charge if they feel threatened.
The guard carries a gun, in case a warning shot is needed,
and with good reason.
More people are killed by buffalo than by any other animal in Kaziranga.
That'll wake you up in the morning.
Many of the park staff have cautionary tales about buffalo.
The buffalo caught him here, through his throat
and the horn came out through his mouth
and flung him before running away.
It's a miracle that he's still alive.
If the wildlife is unfriendly to humans,
it's proving downright hostile to camera traps.
Completely ripped out the scaffold poles,
they've torn the triggers.
While Chadden is convinced it's elephants,
the rest of the crew are not so sure.
This is huge!
It's almost like a human footprint.
You can see the front paw, the rear paw.
We are now two weeks in and it's very frustrating.
I've never actually been anywhere where the animals
go after your equipment and destroy it, more than here.
It's time for the team to do some detective work.
Here is our little security camera.
If any animals are coming through and vandalising our main cameras,
we hope that they're being caught on these little things.
As the crew up their spying efforts,
the guards take them to a promising lead.
Nothing attracts tigers like a rhino carcass.
It's very fresh. It's like from the morning.
And it looks like there's a tiger cub,
so it should be a tigress with cubs, coming to feed on this rhino carcass.
It's pretty cool.
Chadden decides to give the camera traps one last chance.
If there are tigers around, they might scare away the mystery vandals.
Elsewhere in the park,
the security cameras are turning up some unexpected results.
At nighttime, survived another... Ooh!
It's a bear.
Wow, that's a very rare sighting.
I've never seen a bear in Kaziranga.
In all my years, never.
- Oh, his fingernails... - Look at his claws, right on the lens.
So I thought this was elephant damage.
I never thought we'd see a sloth bear doing that.
That's amazing.
A return to the rhino carcass and the plot thickens.
Our transmitter's gone.
That's what tigers think of camera traps.
Do you think there's a bit over there?
Pieces.
The security cameras have caught a new culprit.
Oh, my goodness, there they are.
Ooh!
There it's a tigress, see that. It's a tigress.
It snarled at the camera trap, look at that.
Sure don't like camera traps.
Okay.
With the technology struggling,
Sandesh decides to put himself on the frontline.
- It's on. - And now we're ready.
Time to get the tiger.
He'll have no protection apart from a thin wall of grass,
and must hope he's as well-hidden as the local wildlife.
Over the next five days, Sandesh plays the role
of human camera trap.
Eventually, the more hands-on approach pays off.
Traditional filming methods and a little bit of patience,
have helped reveal the hidden creatures of Kaziranga.
But it's good to know there are still wild places
where animals like to keep their secrets.
I knew it was elephants.
Next time,
we venture to the newest habitat on Earth,
our cities.
To reveal the extraordinary ways
that animals survive in this man-made world.