0:00:37 > 0:00:41Forests cover one third of the lands of the Earth.
0:00:43 > 0:00:48Hiding within them are half of all the animal species on the planet.
0:00:53 > 0:00:56But forests are complex places in which to hunt.
0:01:05 > 0:01:07There is never a clean line of sight.
0:01:11 > 0:01:13No room for the chase.
0:01:18 > 0:01:22To get to its prey in this labyrinthine world...
0:01:22 > 0:01:24DEER CALLS
0:01:24 > 0:01:27..without being discovered...
0:01:30 > 0:01:34..the forest hunter must master the art of the ambush.
0:01:51 > 0:01:55The tiger is the largest of all forest predators.
0:01:58 > 0:02:02Yet its life depends on being able to hide itself...
0:02:04 > 0:02:09..no simple task for a cat weighing up to 200 kilos.
0:02:14 > 0:02:18The vanishing act takes years to perfect...
0:02:20 > 0:02:23..beginning when tigers are just cubs.
0:02:30 > 0:02:32Like domestic kittens, tiger cubs
0:02:32 > 0:02:36can't resist the compulsion to stalk.
0:02:36 > 0:02:38TWIG CRACKS
0:02:38 > 0:02:40MONKEY MAKES ALARM CALL
0:02:44 > 0:02:47At first, it's a game.
0:02:55 > 0:02:57But the cubs are learning the skills
0:02:57 > 0:03:02needed to move silently over the crunchy forest floor.
0:03:09 > 0:03:10It takes practice...
0:03:20 > 0:03:22..and perseverance.
0:03:33 > 0:03:35A cub will fail many times.
0:03:35 > 0:03:37TWIG CRACKS
0:03:37 > 0:03:38MONKEY ALARM CALL
0:03:43 > 0:03:48But, ultimately, its life will depend on getting it right.
0:03:55 > 0:03:58By the time it's a young adult,
0:03:58 > 0:04:02a tiger can move without making a sound.
0:04:10 > 0:04:15But to get close to its prey, it must also be out of sight.
0:04:22 > 0:04:24Herds have many eyes,
0:04:24 > 0:04:26and they never let down their guard.
0:04:33 > 0:04:37As long as they can see the tiger, there can be no ambush.
0:04:44 > 0:04:48As long as they can see...
0:04:48 > 0:04:49the tiger.
0:05:32 > 0:05:34Not close enough.
0:05:39 > 0:05:42To stand a good chance of catching a deer,
0:05:42 > 0:05:46a tiger must stalk to within ten metres
0:05:46 > 0:05:48before launching an attack.
0:05:53 > 0:05:55And to do that,
0:05:55 > 0:05:59it must take advantage of any cover its forest provides.
0:06:07 > 0:06:10THUNDER RUMBLES
0:06:26 > 0:06:30With experience, a tiger becomes expert...
0:06:32 > 0:06:36..at exploiting any opportunity.
0:06:42 > 0:06:45THUNDER RUMBLES
0:06:52 > 0:06:58The noises and darkness of a storm can be used to conceal its approach.
0:07:03 > 0:07:06It moves in downwind of the herd...
0:07:09 > 0:07:11..undetected.
0:07:30 > 0:07:35Once within striking distance, it freezes.
0:07:39 > 0:07:41The final trick for a hunting tiger
0:07:41 > 0:07:43is to get closer
0:07:43 > 0:07:45without moving at all.
0:07:48 > 0:07:51Let the stag come as close as it will.
0:07:55 > 0:07:57Then wait for it to turn...
0:08:00 > 0:08:02..and take one step away.
0:08:15 > 0:08:17The perfect strike...
0:08:18 > 0:08:23..and brave - this stag weighs almost as much as the tiger.
0:08:29 > 0:08:34It instinctively moves its prize out of sight before starting its meal.
0:08:45 > 0:08:46An accomplished ambusher.
0:08:49 > 0:08:53Years in the making,
0:08:53 > 0:08:56with the skills to turn the challenges of its forest
0:08:56 > 0:08:58to its advantage.
0:09:07 > 0:09:09But not all forests are the same.
0:09:12 > 0:09:16They begin where the trees begin, in the far north.
0:09:22 > 0:09:25This is the largest forest of all.
0:09:25 > 0:09:31An unbroken band of coniferous trees that wraps around the globe -
0:09:31 > 0:09:33the Boreal forest.
0:09:39 > 0:09:42In winter, it can appear empty
0:09:42 > 0:09:47but this endless maze is the arena for a unique game of hide and seek.
0:09:54 > 0:09:57Snow falls in this forest for months on end.
0:09:59 > 0:10:02As it collects on the fallen branches and trunks
0:10:02 > 0:10:04that litter the forest floor,
0:10:04 > 0:10:09a hidden labyrinth of snow tunnels is created beneath.
0:10:12 > 0:10:15Here, out of the icy air,
0:10:15 > 0:10:18is where the forest's rodents spend their winter.
0:10:23 > 0:10:28Prey exists even in this seemingly empty forest...
0:10:31 > 0:10:33..if you know where to find it.
0:10:38 > 0:10:40The American marten.
0:10:43 > 0:10:45It only lives where, in winter,
0:10:45 > 0:10:49the snow is deep enough to create this maze.
0:10:51 > 0:10:56Its slim body is ideally shaped for searching snow tunnels,
0:10:56 > 0:11:00but that shape means it also loses heat quickly.
0:11:02 > 0:11:06To stay alive, it must continually search for food.
0:11:11 > 0:11:12The marten picks up a scent.
0:11:25 > 0:11:28It listens for any movement.
0:11:41 > 0:11:42Found you!
0:11:49 > 0:11:51One mouse is not enough.
0:11:53 > 0:11:56To keep warm in this frozen forest,
0:11:56 > 0:11:59the marten must find three mice every day.
0:12:02 > 0:12:08But with thousands of tunnels under the snow, which one do you check?
0:12:11 > 0:12:12You check them all!
0:12:24 > 0:12:26A frantic game of hide and seek.
0:12:31 > 0:12:34Only one in ten tunnels is home to a mouse.
0:12:44 > 0:12:48And even then, finding the mouse is not guaranteed.
0:12:55 > 0:12:58For hunters in the Boreal forest,
0:12:58 > 0:13:02just finding food is the biggest challenge of all.
0:13:09 > 0:13:12In the forest further south, prey is more abundant.
0:13:19 > 0:13:22The deciduous forest we know so well.
0:13:24 > 0:13:27In the summer, it's busy with small birds.
0:13:31 > 0:13:33The trees are thick with foliage.
0:13:36 > 0:13:39It's a complex world in which to navigate.
0:13:42 > 0:13:45A problem for the female sparrowhawk.
0:13:48 > 0:13:51Since she has to produce and lay eggs,
0:13:51 > 0:13:53her body must be of a certain size,
0:13:53 > 0:13:59and she's too big to sneak up on her prey in this crowded habitat.
0:14:01 > 0:14:06At this time of year, she relies on another -
0:14:06 > 0:14:08a smaller, more agile hunter...
0:14:10 > 0:14:14..able to travel at speed through the tangled woodland...
0:14:20 > 0:14:22..the male sparrowhawk.
0:14:28 > 0:14:32He is well suited to hunting in the dense summer forest...
0:14:37 > 0:14:41..but he must give almost everything he catches...
0:14:42 > 0:14:44..to his boss.
0:14:50 > 0:14:52She's twice his size!
0:14:56 > 0:15:04In the summer, she and their young depend on his hunting expertise.
0:15:08 > 0:15:13He never rests, surprising small birds on the wing.
0:15:17 > 0:15:21Ambushing from lofty hiding places.
0:15:25 > 0:15:28He is a specialist summer hunter.
0:15:34 > 0:15:38Each day, he provides up to ten small birds.
0:15:42 > 0:15:45Until the rules of the game change...
0:15:47 > 0:15:48..with autumn.
0:15:54 > 0:15:58The deciduous trees shed their delicate, frost-prone leaves.
0:16:01 > 0:16:04The cover the male relied on all summer...
0:16:06 > 0:16:07..is blown.
0:16:14 > 0:16:19The hunt must change from hide and seek to open chase.
0:16:24 > 0:16:29The greater size of the female sparrowhawk is now an advantage.
0:16:31 > 0:16:36She has the strength and the weight to catch bigger prey.
0:16:39 > 0:16:42Jays are too large for the tiny male to tackle.
0:16:46 > 0:16:51But they are the perfect target practice for the fledgling females.
0:17:01 > 0:17:05They can't resist the challenge.
0:17:40 > 0:17:43It may look like a bit of fun.
0:17:44 > 0:17:47But buzzing jays helps the fledglings learn
0:17:47 > 0:17:51how to hunt in a place where there is no leaf cover.
0:17:53 > 0:17:57In the coming winter, they will rely on the sudden stall...
0:17:58 > 0:18:00..the tail chase...
0:18:04 > 0:18:05..the interception.
0:18:16 > 0:18:18By taking larger prey,
0:18:18 > 0:18:22the females increase their chances of surviving in the winter forest.
0:18:27 > 0:18:31Whereas they can last for a week on just one kill...
0:18:33 > 0:18:36..the male, limited to smaller meals,
0:18:36 > 0:18:39must hunt almost twice as frequently.
0:18:42 > 0:18:46It's the price the sparrowhawk must pay for hunting in a forest
0:18:46 > 0:18:49that changes so radically with the seasons.
0:19:00 > 0:19:05There is a forest where the game of hide and seek is even more complex.
0:19:07 > 0:19:09The rainforest.
0:19:11 > 0:19:15A place in which the perfect conditions for plant life
0:19:15 > 0:19:19never end and the forest runs rampant...
0:19:21 > 0:19:25..forming the most confusing arena of all.
0:19:28 > 0:19:31But there has to be prey hidden somewhere.
0:19:35 > 0:19:38In fact, it's hidden everywhere.
0:19:41 > 0:19:44The great problem of the rainforest is one of scale.
0:19:46 > 0:19:49Most of the prey animals here are tiny.
0:19:51 > 0:19:55How can a predator hope to survive on such small prey?
0:20:01 > 0:20:05One answer is to be a small predator.
0:20:11 > 0:20:14This is a Portia spider.
0:20:17 > 0:20:23Rather than use a web, Portia ventures out in search of prey.
0:20:29 > 0:20:34Playing hide and seek in this,
0:20:34 > 0:20:36the mother of all mazes.
0:20:45 > 0:20:50To help her in her quest, she's equipped with three superpowers.
0:20:52 > 0:20:56First, an amazing approach to getting about.
0:21:02 > 0:21:04Portia is a jumping spider...
0:21:08 > 0:21:12..able to leap up to 50 times her own body length.
0:21:16 > 0:21:19Nowhere seems beyond her reach.
0:21:22 > 0:21:26Next, her second superpower - superb eyesight.
0:21:29 > 0:21:34Essential if she is to distinguish her prey in all this clutter.
0:21:35 > 0:21:38Because her prey doesn't stray.
0:21:42 > 0:21:45Portia is a spider-eating spider.
0:21:49 > 0:21:52This raises a few problems -
0:21:52 > 0:21:55her lunch is three times her size...
0:21:57 > 0:22:00..packed with venom
0:22:00 > 0:22:02and surrounded by a sticky trap.
0:22:06 > 0:22:08Mission impossible?
0:22:08 > 0:22:14Not at all, because of her third superpower.
0:22:14 > 0:22:15Portia is a genius.
0:22:19 > 0:22:23She can map her world in three dimensions...
0:22:24 > 0:22:27..and formulate a plan of attack.
0:22:29 > 0:22:31She can have an idea.
0:22:51 > 0:22:54The web-builder is blind.
0:22:56 > 0:22:58It won't have a clue that she's coming.
0:23:22 > 0:23:24Right on target
0:23:24 > 0:23:27and safely behind those fangs.
0:23:35 > 0:23:41But a mind as active as Portia's can always do with more brain food.
0:23:45 > 0:23:48Here, there's no anchor point for the abseil.
0:23:52 > 0:23:55But Portia has another idea.
0:23:58 > 0:24:00Instead of going to the spider...
0:24:06 > 0:24:08..she will bring the spider to her.
0:24:13 > 0:24:18She plucks the strands to imitate struggling prey...
0:24:22 > 0:24:24..drawing the spider in...
0:24:28 > 0:24:30..to its death.
0:24:36 > 0:24:39But Portia does have her equal...
0:24:44 > 0:24:45..the spitting spider.
0:24:48 > 0:24:52A rival stalker with its own secret weapon.
0:24:53 > 0:24:57A bloated head armed with glue guns...
0:24:59 > 0:25:03..that trap with sticky threads.
0:25:06 > 0:25:09One spit in the eye would blind Portia.
0:25:12 > 0:25:14But she knows how to avoid that.
0:25:17 > 0:25:19Only hunt a female with an egg sac.
0:25:26 > 0:25:29Follow at a safe distance.
0:25:34 > 0:25:37Track it to its lair.
0:25:40 > 0:25:42A dangerous place for Portia.
0:25:49 > 0:25:51But the spitter is distracted.
0:25:53 > 0:25:55She's tending to her eggs.
0:25:58 > 0:26:01Portia waits for just the right moment.
0:26:04 > 0:26:07It can't spit if its mouth is full.
0:26:22 > 0:26:24Mission possible!
0:26:28 > 0:26:31For predators larger than Portia,
0:26:31 > 0:26:37there is one way to find lots of small prey in a short space of time.
0:26:40 > 0:26:42Wait until nightfall.
0:26:48 > 0:26:50Under cover of darkness,
0:26:50 > 0:26:54the forest comes alive with small animals
0:26:54 > 0:26:56trusting that night will hide them.
0:27:03 > 0:27:05It won't.
0:27:09 > 0:27:12Some hunters ambush by moonlight.
0:27:20 > 0:27:22The tarsier.
0:27:23 > 0:27:26No bigger than a human hand...
0:27:28 > 0:27:33..with the largest eyes of any mammal relative to body size,
0:27:33 > 0:27:36and huge, bat-like ears to pick out
0:27:36 > 0:27:39a telltale scratch amongst the hubbub.
0:27:43 > 0:27:45FAINT RUSTLING
0:27:48 > 0:27:52The darkness can't hide an insect from a tarsier...
0:27:55 > 0:27:58..but it can hide a tarsier from an insect.
0:28:11 > 0:28:17Because tarsiers compete for food,
0:28:17 > 0:28:20they keep their distance while hunting...
0:28:23 > 0:28:26..each sweeping its own patch of jungle.
0:28:34 > 0:28:35But while they hunt...
0:28:38 > 0:28:41..they too are hunted.
0:28:45 > 0:28:48They have their own night stalker.
0:28:50 > 0:28:52A reticulated python.
0:29:00 > 0:29:06It uses scent and heat-sensing organs to find its prey in the dark.
0:29:14 > 0:29:17If the tarsiers spot it, they know what to do.
0:29:20 > 0:29:22HIGH-PITCHED CALL Call in the troops!
0:29:25 > 0:29:27All the tarsiers in the neighbourhood
0:29:27 > 0:29:31abandon their hunts and rally together...
0:29:35 > 0:29:39..screaming at the python with high-pitched calls.
0:29:40 > 0:29:44TARSIERS CALL SHRILLY
0:29:47 > 0:29:52The game is up, and the snake is driven away.
0:29:57 > 0:30:00There is safety in numbers,
0:30:00 > 0:30:02but when the commotion is over...
0:30:04 > 0:30:07..it's back to every tarsier for itself.
0:30:30 > 0:30:37By day, a different game of hide and seek takes place high above,
0:30:37 > 0:30:39in the jungle canopy.
0:30:42 > 0:30:44A far more open arena,
0:30:44 > 0:30:47hanging 30 metres up in the air,
0:30:47 > 0:30:50and home to larger prey.
0:30:56 > 0:30:58Troops of monkeys
0:30:58 > 0:31:02feasting on the flowers and fruits of the giant trees.
0:31:05 > 0:31:09Because monkeys are always at risk of falling, they need
0:31:09 > 0:31:13forward-facing eyes to judge the distance to the next branch...
0:31:16 > 0:31:19..which means they have a blind spot.
0:31:28 > 0:31:31The harpy eagle.
0:31:31 > 0:31:34With talons as long as a bear's claws,
0:31:34 > 0:31:39and a two-metre wingspan, it's the master of the aerial ambush.
0:31:43 > 0:31:45If a monkey is under the canopy,
0:31:45 > 0:31:47it's out of the harpy's reach.
0:31:55 > 0:31:57It's only when one breaks cover...
0:31:59 > 0:32:02..that it becomes available.
0:32:10 > 0:32:12MONKEY SCREAMS
0:32:22 > 0:32:25The harpy's way of hunting comes at a price.
0:32:27 > 0:32:31To fly with prey as heavy as a monkey, it must build enough muscle
0:32:31 > 0:32:35to become the most powerful eagle on Earth.
0:32:39 > 0:32:44Raising a harpy chick, therefore, takes an extraordinary commitment.
0:32:52 > 0:32:57Harpies have the longest period of parental care of any bird of prey.
0:33:04 > 0:33:07They feed their chick for up to two years.
0:33:13 > 0:33:19In that time, the parents will bring it over 200 monkeys and sloths.
0:33:27 > 0:33:30At the end of a year, it's fully grown...
0:33:34 > 0:33:36..but it's far from the finished article.
0:33:42 > 0:33:43It must spend many more months
0:33:43 > 0:33:48building up its flight muscles for the heavy lifting ahead
0:33:48 > 0:33:51by working out at the jungle gym.
0:33:56 > 0:33:58And, more demanding still,
0:33:58 > 0:34:03it must learn the art of the ambush in this aerial world.
0:34:17 > 0:34:20Trying to hide from monkeys is not easy.
0:34:36 > 0:34:38There are more straightforward options
0:34:38 > 0:34:40for the chick's first encounter.
0:34:47 > 0:34:49A three-toed sloth...
0:34:51 > 0:34:54..the slowest prey in the jungle...
0:34:54 > 0:34:57with no way of escaping an eagle.
0:35:17 > 0:35:19It should be a formality
0:35:19 > 0:35:22but even sloths fight back.
0:35:36 > 0:35:38It's a valuable lesson.
0:35:41 > 0:35:45Hunting the jungle's larger animals is never simple.
0:35:47 > 0:35:50The chick must raise its game soon.
0:35:51 > 0:35:54After all, this is its parents' territory.
0:35:57 > 0:35:59If it doesn't start hunting for itself,
0:35:59 > 0:36:04even after all their efforts, they may kill it
0:36:04 > 0:36:07to make way for another that will.
0:36:16 > 0:36:19While most forest predators hunt alone...
0:36:23 > 0:36:25..some work as a team.
0:36:30 > 0:36:34Chimpanzees hunt monkeys by using the most complex
0:36:34 > 0:36:37and intelligent ambush of all.
0:36:39 > 0:36:41When they decide to do so,
0:36:41 > 0:36:46the whole troop sets out on an extended trek in search of prey.
0:36:46 > 0:36:49LOW RUMBLING CALLS
0:36:49 > 0:36:55Once they hear monkey calls, all the chimps switch to silent mode.
0:37:01 > 0:37:03Carefully, they move in beneath.
0:37:07 > 0:37:12Colobus monkeys, 30 metres up in the dense canopy.
0:37:16 > 0:37:18It's almost impossible
0:37:18 > 0:37:22for a single chimp to catch a monkey in this forest.
0:37:22 > 0:37:25The colobus are less than half their weight,
0:37:25 > 0:37:29and can escape using small branches that cannot support a chimp.
0:37:32 > 0:37:35The chimps must work together to set a trap.
0:37:39 > 0:37:41The most accomplished hunter
0:37:41 > 0:37:44judges the possible escape route of the colobus,
0:37:44 > 0:37:46and moves silently ahead in the forest.
0:37:50 > 0:37:53He takes up an advanced, ambusher position,
0:37:53 > 0:37:56hidden in the branches just below the canopy.
0:38:04 > 0:38:06Other chimps, the blockers,
0:38:06 > 0:38:09take his lead, climbing up either side of the colobus,
0:38:09 > 0:38:13making themselves obvious to close off other escape routes.
0:38:21 > 0:38:24The last chimp is the driver.
0:38:26 > 0:38:29His job will be to chase the colobus into the trap.
0:38:38 > 0:38:41When all are in position, he launches the attack.
0:39:00 > 0:39:02While the driver keeps up the momentum,
0:39:02 > 0:39:05the blockers move to close any gaps.
0:39:11 > 0:39:13The monkeys flee towards the trap.
0:39:20 > 0:39:25When they reach the ambush tree, the trap is sprung.
0:39:25 > 0:39:28CHIMPS SCREAM
0:39:35 > 0:39:37A colobus is brought to the ground.
0:39:46 > 0:39:48Everyone is desperate for a share.
0:39:50 > 0:39:53But the meat is divided up in a specific way.
0:39:55 > 0:39:58The hunters take the choice cuts.
0:40:02 > 0:40:05High-ranking females and their offspring get their share.
0:40:10 > 0:40:12CHIMPS GRUNT AND WHOOP
0:40:12 > 0:40:15Males who played no part in the hunt feel hard done by,
0:40:15 > 0:40:18and become frustrated and sulky.
0:40:18 > 0:40:21CHIMPS SCREAM
0:40:27 > 0:40:33Meat is a precious treat in the troop's largely vegetarian diet.
0:40:35 > 0:40:38But it plays a vital role in chimp society.
0:40:42 > 0:40:43In sharing their catch,
0:40:43 > 0:40:49the chimps reinforce the bonds that enable them to succeed as a group.
0:40:53 > 0:40:56But for all the chimps' intelligence and teamwork,
0:40:56 > 0:41:00their hunts only succeed about half the time.
0:41:04 > 0:41:06In fact, there's only one animal
0:41:06 > 0:41:10that has mastered the forest hunt enough to win every time.
0:41:16 > 0:41:18There is nowhere to hide from it.
0:41:22 > 0:41:27It is the most successful player of hide and seek on Earth...
0:41:33 > 0:41:34..the army ant.
0:41:38 > 0:41:41This may look like a ball of a million individuals,
0:41:41 > 0:41:44but make no mistake -
0:41:44 > 0:41:46the colony acts as one.
0:41:49 > 0:41:53A super-organism with a sensory system of two million antennae.
0:41:56 > 0:41:59A skeleton made from the living bodies of workers.
0:42:04 > 0:42:06A defence system of soldier ants...
0:42:08 > 0:42:11..ready to act at any sign of danger...
0:42:13 > 0:42:18..a digestive system processing piles of food deep inside.
0:42:20 > 0:42:25Even a coordinated system for dealing with all the waste.
0:42:28 > 0:42:34These are insects that, by working together, transcend individual size.
0:42:37 > 0:42:41The colony can search the entire jungle...
0:42:42 > 0:42:44..and flush out its wildlife.
0:42:52 > 0:42:55Each day, it sends out a silent probe into the forest
0:42:55 > 0:42:57in quest of food.
0:43:05 > 0:43:08It doesn't use scouts like other ants.
0:43:12 > 0:43:16Instead, a vast search party pushes into virgin territory...
0:43:21 > 0:43:25..seeking out the signs of anything alive.
0:43:37 > 0:43:41They spread out along a ten-metre front,
0:43:41 > 0:43:43sweeping across the forest floor.
0:43:46 > 0:43:49To find prey, the ants must first touch it.
0:43:51 > 0:43:55The irony is that this, the most successful hide and seek player
0:43:55 > 0:43:58in the forest, is almost completely blind.
0:44:01 > 0:44:04It distinguishes the living only by their movement.
0:44:08 > 0:44:12As long as an animal remains still, it is safe.
0:44:15 > 0:44:18But the slightest twitch will give it away.
0:44:23 > 0:44:26Within seconds, the prey is pinned down.
0:44:29 > 0:44:32Within minutes, it's torn apart at its joints.
0:44:37 > 0:44:41The more the prey struggles, the more the ants engage.
0:44:46 > 0:44:48Right across the raid front,
0:44:48 > 0:44:51prey of all sizes are driven from their hiding places.
0:44:55 > 0:45:00Even wasps must abandon their homes when the ants arrive.
0:45:05 > 0:45:08Everything alive in the path of the raiders
0:45:08 > 0:45:13overwhelmed by sheer numbers.
0:45:22 > 0:45:24All this prey is just an appetizer.
0:45:28 > 0:45:31The army has found one of its chief targets...
0:45:32 > 0:45:36..a colony of a different kind of ant.
0:45:39 > 0:45:41The nest is at the top of this tree.
0:45:43 > 0:45:47The defending black ants swarm down the tree trunk,
0:45:47 > 0:45:50and take up positions on the branches.
0:45:54 > 0:45:57But the army ants send in a legion.
0:45:59 > 0:46:03They lock jaws with the black ants and leap from the tree
0:46:03 > 0:46:05to take them out of the battle.
0:46:16 > 0:46:20Casualties on both sides rain down from the canopy.
0:46:27 > 0:46:30But the army ants don't want the adults.
0:46:37 > 0:46:40They are seeking the soft-skinned juicy larvae.
0:46:43 > 0:46:47A whole generation of white grubs is plundered.
0:46:53 > 0:46:57The spoils of the ant war are carried along trails
0:46:57 > 0:46:59leading back to the main colony.
0:47:01 > 0:47:04Other lines are fresh from other victories.
0:47:19 > 0:47:23The army ant raid is an unequalled phenomenon.
0:47:28 > 0:47:31Over a million hunters
0:47:31 > 0:47:35chasing hundreds of species of prey animals.
0:47:40 > 0:47:45By the time the super-organism returns to its nest each day,
0:47:45 > 0:47:4830,000 animals will have been caught.
0:47:52 > 0:47:55It's the largest hunt on Earth,
0:47:55 > 0:47:58executed by one of its smallest hunters.
0:48:02 > 0:48:03Hide and seek?
0:48:04 > 0:48:06Game over.
0:48:17 > 0:48:20How do you film a tiger hunting in the forest?
0:48:21 > 0:48:24That's the challenge the crew faced in India.
0:48:27 > 0:48:30Only a handful of tiger hunts have ever been filmed.
0:48:31 > 0:48:36So to film the world expert at hide and seek within the forest,
0:48:36 > 0:48:39the crew needed a revolutionary new approach.
0:48:46 > 0:48:51They put a stabilised cineflex camera on a crane on a Jeep.
0:48:53 > 0:48:55So this lets us put the camera right down on the deck
0:48:55 > 0:48:57to get a really nice low angle through the forest.
0:48:57 > 0:49:01If we have to look over the foliage, then we can lift it up, um,
0:49:01 > 0:49:04basically try and keep the tigers in view for as long as possible.
0:49:04 > 0:49:06They concentrated their efforts
0:49:06 > 0:49:10on the territory of a female with four grown-up cubs.
0:49:11 > 0:49:15Actually mother and four cubs coming this side,
0:49:15 > 0:49:18going through this trail you can see behind.
0:49:18 > 0:49:20Right, I'm just going to show you something
0:49:20 > 0:49:21because it shocked me a little bit.
0:49:21 > 0:49:24That's leopard footprints.
0:49:24 > 0:49:28And right behind them, that's a tiger footprint.
0:49:28 > 0:49:30Biggest forest predator on Earth.
0:49:35 > 0:49:39With the last location of the mother and her cubs identified,
0:49:39 > 0:49:41the next step is to wait.
0:49:45 > 0:49:49In time, the forest will give away the tigers' location.
0:49:51 > 0:49:53VARIOUS ANIMALS CALL
0:49:53 > 0:49:58This side - a spotted deer giving an alarm call.
0:49:58 > 0:50:00We go to check, check there.
0:50:02 > 0:50:07These animal alarms signal where the tigers are and where they're going.
0:50:10 > 0:50:11DEER CALLS
0:50:11 > 0:50:14Alarm calls, getting nearer and nearer.
0:50:14 > 0:50:16It's like listening to approaching thunder.
0:50:21 > 0:50:23Finally!
0:50:37 > 0:50:41After a few precious moments, the tiger disappears again.
0:50:43 > 0:50:47It's a very thick forest here. We can't see in, let alone film in.
0:50:47 > 0:50:51So we've got to have some way of getting in there safely
0:50:51 > 0:50:53so we can be near the tigers.
0:50:53 > 0:50:55Luckily, we've got just the thing.
0:50:57 > 0:51:00Months before the shoot, in England, work was under way to come up with
0:51:00 > 0:51:04a new answer to the problem of filming tigers in the forest.
0:51:06 > 0:51:09The best way of filming tigers is actually to be on an elephant,
0:51:09 > 0:51:11because tigers don't care about elephants.
0:51:11 > 0:51:14They're habituated to them. They don't mind.
0:51:14 > 0:51:16The idea was to move the cineflex camera
0:51:16 > 0:51:18from the Jeep to an elephant...
0:51:22 > 0:51:27..using a bespoke device nicknamed the eleflex.
0:51:30 > 0:51:32That's brilliant!
0:51:32 > 0:51:37Built from lightweight aluminium, the eleflex weighs less than a man -
0:51:37 > 0:51:40no burden to an animal as large and strong as an elephant.
0:51:42 > 0:51:44I'll be sat on top of the elephant.
0:51:44 > 0:51:46Why?
0:51:46 > 0:51:48So I don't get eaten by a tiger.
0:51:50 > 0:51:52So what's our chief problems?
0:51:52 > 0:51:54We haven't got an elephant.
0:51:56 > 0:51:57After a series of tests,
0:51:57 > 0:52:01the eleflex is ready for its field trials in India.
0:52:02 > 0:52:04Do you like your new tripod, Jamie?
0:52:07 > 0:52:12Indian tiger parks routinely use domesticated elephants
0:52:12 > 0:52:14to patrol the forest for poachers.
0:52:15 > 0:52:18Gotham, a 65-year-old male,
0:52:18 > 0:52:20has worked with the park rangers all his life.
0:52:22 > 0:52:25Now, he's an integral member of a wildlife film crew.
0:52:35 > 0:52:38The device was designed to fit to the howdah,
0:52:38 > 0:52:40the huge saddle that elephants carry.
0:52:43 > 0:52:47Yeah, we definitely need a howdah that starts at a much higher angle.
0:52:47 > 0:52:48The field trials reveal
0:52:48 > 0:52:52that the eleflex needs a few structural adjustments.
0:52:56 > 0:53:01We're going to the next town here, um, just to find a metal worker
0:53:01 > 0:53:03who can help us strengthen it
0:53:03 > 0:53:06and a tailor to help us build some counterweight bags.
0:53:17 > 0:53:19So some new improvements,
0:53:19 > 0:53:24we've got the metalwork brace that we got made yesterday.
0:53:24 > 0:53:27On the other side, we've got some new weights made by the tailor.
0:53:27 > 0:53:31So all in all, I think we've got
0:53:31 > 0:53:35the howdah to balance perfectly straight now.
0:53:36 > 0:53:38Yeah, power up.
0:53:39 > 0:53:43It's time for Jamie to take the eleflex for a test drive.
0:54:02 > 0:54:04So I'm up on Gotham -
0:54:04 > 0:54:07it works a treat with the eleflex, as we're calling it.
0:54:07 > 0:54:10That means we can actually get off road and get into the forest
0:54:10 > 0:54:13and, um, stick with the tigers.
0:54:13 > 0:54:15It's tricky, but it works.
0:54:15 > 0:54:18It really does. I think we're going to get some great stuff.
0:54:18 > 0:54:20Ready for all eventualities,
0:54:20 > 0:54:24the only thing left to do each day is find the tigers.
0:54:31 > 0:54:35Most days, however, the crew lose the game of hide and seek.
0:54:38 > 0:54:40I've never known a shoot quite like this.
0:54:40 > 0:54:45Never spent so little time with the animals we're trying to film.
0:54:45 > 0:54:48But every now and again, their luck changes.
0:54:48 > 0:54:50Found you!
0:54:51 > 0:54:53Just as slow as you can, Diggy.
0:55:00 > 0:55:03The game goes on for eight weeks.
0:55:08 > 0:55:10The crew throw everything at it.
0:55:12 > 0:55:14Actually, I'm being followed right now.
0:55:17 > 0:55:20Gradually, bit by bit,
0:55:20 > 0:55:21the sequence comes together
0:55:21 > 0:55:25until the only thing that evades them is a successful hunt.
0:55:33 > 0:55:37We were tracking her,
0:55:37 > 0:55:41and then we've picked up two stags walking together,
0:55:41 > 0:55:42we couldn't see her at all
0:55:42 > 0:55:44and we followed the two stags then back towards her.
0:55:50 > 0:55:51We got a tiger kill.
0:55:53 > 0:55:55Yeah, amazing. Very exciting.
0:55:57 > 0:56:00The tiger hurriedly drags her kill out of the sight of rivals.
0:56:04 > 0:56:07But tigers don't regard elephants as rivals.
0:56:14 > 0:56:17The eleflex meant that we could get on to the elephant
0:56:17 > 0:56:20and we could go in with her and finish the sequence off.
0:56:22 > 0:56:26Grabbing a filming first is prize enough for the crew
0:56:26 > 0:56:29but Gotham deserves his reward.
0:56:31 > 0:56:34So that's what you need to play hide and seek with tigers!
0:56:34 > 0:56:37A lot of patience, Jeep, a fancy stabilised camera...
0:56:39 > 0:56:42..an elephant and the luck of the gods.
0:56:42 > 0:56:45But, um, came together. We managed to do it.
0:56:45 > 0:56:46Bye, Gotham.
0:56:51 > 0:56:54Next time, the hunt is on out in the open ocean,
0:56:54 > 0:56:56where prey is so scarce
0:56:56 > 0:57:00that predators are locked in a constant search for food.
0:57:07 > 0:57:11Yet this is home to the most remarkable hunters,
0:57:11 > 0:57:14including the mighty blue whale.