Forests cover one third of the lands of the Earth.
Hiding within them are half of all the animal species on the planet.
But forests are complex places in which to hunt.
There is never a clean line of sight.
No room for the chase.
To get to its prey in this labyrinthine world...
DEER CALLS
..without being discovered...
..the forest hunter must master the art of the ambush.
The tiger is the largest of all forest predators.
Yet its life depends on being able to hide itself -
no simple task for a cat weighing up to 200 kilos.
The vanishing act takes years to perfect...
..beginning when tigers are just cubs.
Like domestic kittens, tiger cubs
can't resist the compulsion to stalk.
TWIG CRACKS
MONKEY MAKES ALARM CALL
At first, it's a game.
But the cubs are learning the skills
needed to move silently over the crunchy forest floor.
It takes practice...
..and perseverance.
A cub will fail many times.
TWIG CRACKS
MONKEY ALARM CALL
But, ultimately, its life will depend on getting it right.
By the time it is a young adult,
a tiger can move without making a sound.
But to get close to its prey, it must also be out of sight.
Herds have many eyes,
and they never let down their guard.
As long as they can see the tiger, there can be no ambush.
As long as they can see...
the tiger.
Not close enough.
To stand a good chance of catching a deer,
a tiger must stalk to within ten metres
before launching an attack.
And to do that,
it must take advantage of any cover its forest provides.
THUNDER RUMBLES
With experience, a tiger becomes expert
at exploiting any opportunity.
THUNDER RUMBLES
The noises and darkness of a storm can be used to conceal its approach.
It moves in downwind of the herd...
..undetected.
Once within striking distance, it freezes.
The final trick for a hunting tiger
is to get closer
without moving at all.
Let the stag come as close as it will.
Then wait for it to turn
and take one step away.
The perfect strike...
and brave - this stag weighs almost as much as the tiger.
It instinctively moves its prize out of sight before starting its meal.
An accomplished ambusher.
Years in the making,
with the skills to turn the challenges of its forest
to its advantage.
But not all forests are the same.
They begin where the trees begin, in the far north.
This is the largest forest of all.
An unbroken band of coniferous trees that wraps around the globe -
the Boreal forest.
In winter, it can appear empty
but this endless maze is the arena for a unique game of hide and seek.
Snow falls in this forest for months on end.
As it collects on the fallen branches and trunks
that litter the forest floor,
a hidden labyrinth of snow tunnels is created beneath.
Here, out of the icy air,
is where the forest's rodents spend their winter.
Prey exists even in this seemingly empty forest...
if you know where to find it.
The American marten.
It only lives where, in winter,
the snow is deep enough to create this maze.
Its slim body is ideally shaped for searching snow tunnels,
but that shape means it also loses heat quickly.
To stay alive, it must continually search for food.
The marten picks up a scent.
It listens for any movement.
Found you!
One mouse is not enough.
To keep warm in this frozen forest,
the marten must find three mice every day.
But with thousands of tunnels under the snow, which one do you check?
You check them all!
A frantic game of hide and seek.
Only one in ten tunnels is home to a mouse.
And even then, finding the mouse is not guaranteed.
For hunters in the Boreal forest,
just finding food is the biggest challenge of all.
In the forest further south, prey is more abundant.
The deciduous forest we know so well.
In the summer, it's busy with small birds.
The trees are thick with foliage.
It's a complex world in which to navigate.
A problem for the female sparrowhawk.
Since she has to produce and lay eggs,
her body must be of a certain size,
and she's too big to sneak up on her prey in this crowded habitat.
At this time of year, she relies on another -
a smaller, more agile hunter
able to travel at speed through the tangled woodland -
the male sparrowhawk.
He is well suited to hunting in the dense summer forest
but he must give almost everything he catches...
to his boss.
She's twice his size!
In the summer, she and their young depend on his hunting expertise.
He never rests, surprising small birds on the wing.
Ambushing from lofty hiding places.
He is a specialist summer hunter.
Each day, he provides up to ten small birds.
Until the rules of the game change...
with autumn.
The deciduous trees shed their delicate, frost-prone leaves.
The cover the male relied on all summer...
is blown.
The hunt must change from hide and seek to open chase.
The greater size of the female sparrowhawk is now an advantage.
She has the strength and the weight to catch bigger prey.
Jays are too large for the tiny male to tackle.
But they are the perfect target practice for the fledgling females.
They can't resist the challenge.
It may look like a bit of fun.
But buzzing jays helps the fledglings learn
how to hunt in a place where there is no leaf cover.
In the coming winter, they will rely on the sudden stall...
the tail chase...
the interception...
By taking larger prey,
the females increase their chances of surviving in the winter forest.
Whereas they can last for a week on just one kill,
the male, limited to smaller meals,
must hunt almost twice as frequently.
It's the price the sparrowhawk must pay for hunting in a forest
that changes so radically with the seasons.
There is a forest where the game of hide and seek is even more complex.
The rainforest.
A place in which the perfect conditions for plant life
never end and the forest runs rampant,
forming the most confusing arena of all.
But there has to be prey hidden somewhere.
In fact, it's hidden everywhere.
The great problem of the rainforest is one of scale.
Most of the prey animals here are tiny.
How can a predator hope to survive on such small prey?
One answer is to be a small predator.
This is a Portia spider.
Rather than use a web, Portia ventures out in search of prey.
Playing hide and seek in this,
the mother of all mazes.
To help her in her quest, she's equipped with three superpowers.
First, an amazing approach to getting about.
Portia is a jumping spider,
able to leap up to 50 times her own body length.
Nowhere seems beyond her reach.
Next, her second superpower - superb eyesight.
Essential if she is to distinguish her prey in all this clutter.
Because her prey doesn't stray.
Portia is a spider-eating spider.
This raises a few problems -
her lunch is three times her size...
packed with venom
and surrounded by a sticky trap.
Mission impossible?
Not at all, because of her third superpower.
Portia is a genius.
She can map her world in three dimensions
and formulate a plan of attack.
She can have an idea.
The web-builder is blind.
It won't have a clue that she's coming.
Right on target
and safely behind those fangs.
But a mind as active as Portia's can always do with more brain food.
Here, there's no anchor point for the abseil.
But Portia has another idea.
Instead of going to the spider...
she will bring the spider to her.
She plucks the strands to imitate struggling prey...
drawing the spider in..
to its death.
But Portia does have her equal -
the spitting spider.
A rival stalker with its own secret weapon.
A bloated head armed with glue guns
that trap with sticky threads.
One spit in the eye would blind Portia.
But she knows how to avoid that.
Only hunt a female with an egg sac.
Follow at a safe distance.
Track it to its lair.
A dangerous place for Portia.
But the spitter is distracted.
She's tending to her eggs.
Portia waits for just the right moment.
It can't spit if its mouth is full.
Mission possible!
For predators larger than Portia,
there is one way to find lots of small prey in a short space of time.
Wait until nightfall.
Under cover of darkness,
the forest comes alive with small animals
trusting that night will hide them.
It won't.
Some hunters ambush by moonlight.
The tarsier.
No bigger than a human hand,
with the largest eyes of any mammal relative to body size,
and huge, bat-like ears to pick out
a telltale scratch amongst the hubbub.
FAINT RUSTLING
The darkness can't hide an insect from a tarsier...
but it can hide a tarsier from an insect.
Because tarsiers compete for food,
they keep their distance while hunting...
each sweeping its own patch of jungle.
But while they hunt...
they too are hunted.
They have their own night stalker.
A reticulated python.
It uses scent and heat-sensing organs to find its prey in the dark.
If the tarsiers spot it, they know what to do.
HIGH-PITCHED CALL Call in the troops!
All the tarsiers in the neighbourhood
abandon their hunts and rally together...
..screaming at the python with high-pitched calls.
TARSIERS CALL SHRILLY
The game is up, and the snake is driven away.
There is safety in numbers,
but when the commotion is over,
it's back to every tarsier for itself.
By day, a different game of hide and seek takes place high above,
in the jungle canopy.
A far more open arena,
hanging 30 metres up in the air,
and home to larger prey.
Troops of monkeys
feasting on the flowers and fruits of the giant trees.
Because monkeys are always at risk of falling, they need
forward-facing eyes to judge the distance to the next branch...
..which means they have a blind spot.
The harpy eagle. With talons as long as a bear's claws,
and a two-metre wingspan, it's the master of the aerial ambush.
If a monkey is under the canopy,
it's out of the harpy's reach.
It's only when one breaks cover
that it becomes available.
MONKEY SCREAMS
The harpy's way of hunting comes at a price.
To fly with prey as heavy as a monkey, it must build enough muscle
to become the most powerful eagle on Earth.
Raising a harpy chick, therefore, takes an extraordinary commitment.
Harpies have the longest period of parental care of any bird of prey.
They feed their chick for up to two years.
In that time, the parents will bring it over 200 monkeys and sloths.
At the end of a year, it's fully grown
but it's far from the finished article.
It must spend many more months
building up its flight muscles for the heavy lifting ahead
by working out at the jungle gym.
And, more demanding still,
it must learn the art of the ambush in this aerial world.
Trying to hide from monkeys is not easy.
There are more straightforward options
for the chick's first encounter.
A three-toed sloth -
the slowest prey in the jungle...
with no way of escaping an eagle.
It should be a formality
but even sloths fight back.
It's a valuable lesson.
Hunting the jungle's larger animals is never simple.
The chick must raise its game soon.
After all, this is its parents' territory.
If it doesn't start hunting for itself,
even after all their efforts, they may kill it
to make way for another that will.
While most forest predators hunt alone,
some work as a team.
Chimpanzees hunt monkeys by using the most complex
and intelligent ambush of all.
When they decide to do so,
the whole troop sets out on an extended trek in search of prey.
LOW RUMBLING CALLS
Once they hear monkey calls, all the chimps switch to silent mode.
Carefully, they move in beneath.
Colobus monkeys, 30 metres up in the dense canopy.
It's almost impossible
for a single chimp to catch a monkey in this forest.
The colobus are less than half their weight,
and can escape using small branches that cannot support a chimp.
The chimps must work together to set a trap.
The most accomplished hunter
judges the possible escape route of the colobus,
and moves silently ahead in the forest.
He takes up an advanced, ambusher position,
hidden in the branches just below the canopy.
Other chimps, the blockers,
take his lead, climbing up either side of the colobus,
making themselves obvious to close off other escape routes.
The last chimp is the driver.
His job will be to chase the colobus into the trap.
When all are in position, he launches the attack.
While the driver keeps up the momentum,
the blockers move to close any gaps.
The monkeys flee towards the trap.
When they reach the ambush tree, the trap is sprung.
CHIMPS SCREAM
A colobus is brought to the ground.
Everyone is desperate for a share.
But the meat is divided up in a specific way.
The hunters take the choice cuts.
High-ranking females and their offspring get their share.
CHIMPS GRUNT AND WHOOP
Males who played no part in the hunt feel hard done by,
and become frustrated and sulky.
CHIMPS SCREAM
Meat is a precious treat in the troop's largely vegetarian diet.
But it plays a vital role in chimp society.
In sharing their catch,
the chimps reinforce the bonds that enable them to succeed as a group.
But for all the chimps' intelligence and teamwork,
their hunts only succeed about half the time.
In fact, there's only one animal
that has mastered the forest hunt enough to win every time.
There is nowhere to hide from it.
It is the most successful player of hide and seek on Earth...
the army ant.
This may look like a ball of a million individuals,
but make no mistake -
the colony acts as one.
A super-organism with a sensory system of two million antennae.
A skeleton made from the living bodies of workers.
A defence system of soldier ants
ready to act at any sign of danger,
a digestive system processing piles of food deep inside.
Even a coordinated system for dealing with all the waste.
These are insects that, by working together, transcend individual size.
The colony can search the entire jungle
and flush out its wildlife.
Each day, it sends out a silent probe into the forest
in quest of food.
It doesn't use scouts like other ants.
Instead, a vast search party pushes into virgin territory...
seeking out the signs of anything alive.
They spread out along a ten-metre front,
sweeping across the forest floor.
To find prey, the ants must first touch it.
The irony is that this, the most successful hide and seek player
in the forest, is almost completely blind.
It distinguishes the living only by their movement.
As long as an animal remains still, it is safe.
But the slightest twitch will give it away.
Within seconds, the prey is pinned down.
Within minutes, it's torn apart at its joints.
The more the prey struggles, the more the ants engage.
Right across the raid front,
prey of all sizes are driven from their hiding places.
Even wasps must abandon their homes when the ants arrive.
Everything alive in the path of the raiders
overwhelmed by sheer numbers.
All this prey is just an appetizer.
The army has found one of its chief targets -
a colony of a different kind of ant.
The nest is at the top of this tree.
The defending black ants swarm down the tree trunk,
and take up positions on the branches.
But the army ants send in a legion.
They lock jaws with the black ants and leap from the tree
to take them out of the battle.
Casualties on both sides rain down from the canopy.
But the army ants don't want the adults.
They are seeking the soft-skinned juicy larvae.
A whole generation of white grubs is plundered.
The spoils of the ant war are carried along trails
leading back to the main colony.
Other lines are fresh from other victories.
The army ant raid is an unequalled phenomenon.
Over a million hunters
chasing hundreds of species of prey animals.
By the time the super-organism returns to its nest each day,
30,000 animals will have been caught.
It's the largest hunt on Earth,
executed by one of its smallest hunters.
Hide and seek?
Game over.
How do you film a tiger hunting in the forest?
That's the challenge the crew faced in India.
Only a handful of tiger hunts have ever been filmed.
So to film the world expert at hide and seek within the forest,
the crew needed a revolutionary new approach.
They put a stabilised cineflex camera on a crane on a Jeep.
So this lets us put the camera right down on the deck
to get a really nice low angle thought the forest.
If we have to look over the foliage, then we can lift it up, um,
basically try and keep the tigers in view for as long as possible.
They concentrated their efforts
on the territory of a female with four grown-up cubs.
Actually mother and four cubs coming this side,
going through this trail you can see behind.
Right, I'm just going to show you something
because it shocked me a little bit.
That's leopard footprints.
And right behind them, that's a tiger footprint.
Biggest forest predator on Earth.
With the last location of the mother and her cubs identified,
the next step is to wait.
In time, the forest will give away the tigers' location.
VARIOUS ANIMALS CALL
This side - a spotted deer giving an alarm call.
We go to check, check there.
These animal alarms signal where the tigers are and where they are going.
DEER CALLS
Alarm calls, getting nearer and nearer.
It's like listening to approaching thunder.
Finally!
After a few precious moments, the tiger disappears again.
It's very thick forest here. We can't see in, let alone film in.
So we've got to have some way of getting in there safely
so we can be near the tigers.
Luckily, we've got just the thing.
Months before the shoot, in England, work was under way to come up with
a new answer to the problem of filming tigers in the forest.
The best way of filming tigers is actually to be on an elephant,
because tigers don't care about elephants.
They're habituated to them. They don't mind.
The idea was to move the cineflex camera
from the Jeep to an elephant...
using a bespoke device nicknamed the eleflex.
That's brilliant!
Built from lightweight aluminium, the eleflex weighs less than a man -
no burden to an animal as large and strong as an elephant.
I'll be sat on top of the elephant.
Why?
So I don't get eaten by a tiger.
So what's our chief problems?
We haven't got an elephant.
After a series of tests,
the eleflex is ready for its field trials in India.
Like your new tripod, Jamie.
Indian tiger parks routinely use domesticated elephants
to patrol the forest for poachers.
Gotham, a 65-year-old male,
has worked with the park rangers all his life.
Now, he's an integral member of a wildlife film crew.
The device was designed to fit to the howdah,
the huge saddle that elephants carry.
Yeah, we definitely need a howdah that starts at a much higher angle.
The field trials reveal
that the eleflex needs a few structural adjustments.
We're going to the next town here, um, just to find a metal worker
who can help us strengthen it
and a tailor to help us build some counterweight bags.
So some new improvements,
we've got the metalwork brace that we got made yesterday.
On the other side, we've got some new weights made by the tailor.
So all in all, I think we've got
the howdah to balance perfectly straight now.
Yeah, power up.
It's time for Jamie to take the eleflex for a test drive.
So I'm up on Gotham -
it works a treat with the eleflex, as we're calling it.
That means we can actually get off road and get into the forest
and um, stick with the tigers.
It's tricky, but it works.
It really does. I think we're going to get some great stuff.
Ready for all eventualities,
the only thing left to do each day is find the tigers.
Most days, however, the crew lose the game of hide and seek.
I've never known a shoot quite like this.
Never spent so little time with the animals we're trying to film.
But every now and again, their luck changes.
Found you!
Just as slow as you can, Diggy.
The game goes on for eight weeks.
The crew throw everything at it.
Actually, I'm being followed right now.
Gradually, bit by bit,
the sequence comes together
until the only thing that evades them is a successful hunt.
We were tracking her,
and then we picked up two stags walking together,
we couldn't see her at all
and we followed the two stags then back towards her.
We got a tiger kill.
Yeah, amazing. Very exciting.
The tiger hurriedly drags her kill out of the sight of rivals.
But tigers don't regard elephants as rivals.
The eleflex meant that we could get on to the elephant
and we could go in with her and finish the sequence off.
Grabbing a filming first is prize enough for the crew
but Gotham deserves his reward.
So that's what you need to play hide and seek with tigers!
A lot of patience, Jeep, a fancy stabilised camera,
an elephant and the luck of the gods.
But um, came together. We managed to do it.
Bye, Gotham.
Next time, the hunt is on out in the open ocean,
where prey is so scarce
that predators are locked in a constant search for food.
Yet this is home to the most remarkable hunters,
including the mighty blue whale.
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