0:00:03 > 0:00:07This is the inside story of four extraordinary predators.
0:00:07 > 0:00:09The peregrine falcon...
0:00:09 > 0:00:11the Nile crocodile...
0:00:11 > 0:00:13the cheetah...
0:00:13 > 0:00:15and the great white shark.
0:00:23 > 0:00:27With ground-breaking computer graphics...
0:00:27 > 0:00:31and incredible close-up photography...
0:00:31 > 0:00:35we reveal the inner alchemy that gives our hunters the edge.
0:00:39 > 0:00:45Reconstructing their intimate lives as they make their kills.
0:00:51 > 0:00:54But who is the planet's perfect predator?
0:01:20 > 0:01:23Living right above the heads of the people of London...
0:01:27 > 0:01:30..the fastest animal on the planet,
0:01:30 > 0:01:32the peregrine falcon.
0:01:44 > 0:01:49Man-made cliff tops offer sanctuary to the peregrines...
0:01:51 > 0:01:53..but they also present new dangers.
0:02:06 > 0:02:09With the arrival of spring come new demands
0:02:09 > 0:02:10on the peregrines' hunting skills.
0:02:10 > 0:02:13Demands that will stretch them to their limit.
0:02:30 > 0:02:31There are new mouths to feed.
0:02:40 > 0:02:44If these chicks are to survive long enough to fly the nest,
0:02:44 > 0:02:49their parents will have to catch two pigeons a day for the next month.
0:03:00 > 0:03:04This will be the greatest challenge of their mother's life.
0:03:13 > 0:03:16Her secret weapon is speed.
0:03:22 > 0:03:26But on the flat, a pigeon can out-fly a peregrine.
0:03:28 > 0:03:33She must use gravity to reach her maximum speed.
0:03:38 > 0:03:41For this, she rides the updraft.
0:03:54 > 0:03:56Half a mile above the city,
0:03:56 > 0:04:01she can now survey the whole of her territory.
0:04:02 > 0:04:04Of all the four predators,
0:04:04 > 0:04:07the peregrine falcon has the keenest eyesight.
0:04:10 > 0:04:12At the base of each retina,
0:04:12 > 0:04:15she has two concentrations of visual sensors,
0:04:15 > 0:04:18where humans have only one.
0:04:20 > 0:04:23This gives her incredible powers of triangulation.
0:04:25 > 0:04:30From two miles away, she locks on to her unsuspecting target.
0:04:31 > 0:04:33The hunt is on.
0:04:46 > 0:04:50While this peregrine falcon must kill every day,
0:04:50 > 0:04:55there's one predator that can survive without food for a year.
0:04:59 > 0:05:02It lives in the rivers of Africa.
0:05:03 > 0:05:05Even when they have run dry.
0:05:28 > 0:05:33Months ago a five-metre, half-ton Nile crocodile
0:05:33 > 0:05:36scraped out a burrow to escape the heat.
0:05:40 > 0:05:43Now he's in a state of suspended animation.
0:05:50 > 0:05:54His heart beats only twice a minute...
0:05:57 > 0:05:59..delivering just enough blood
0:06:00 > 0:06:03to keep his vital organs from shutting down completely.
0:06:10 > 0:06:15To survive, he draws on the fat reserves
0:06:15 > 0:06:17accumulated from last year's hunt.
0:06:24 > 0:06:28In this condition, he rides out the worst of the drought.
0:06:31 > 0:06:35THUNDER RUMBLES
0:07:05 > 0:07:08When the rains finally return...
0:07:09 > 0:07:11..the predator
0:07:11 > 0:07:13flickers to life.
0:07:28 > 0:07:35But before the cold-bloodied reptile can hunt, it must first power up.
0:07:50 > 0:07:55The ridges of scales along his back are more than just body armour.
0:07:57 > 0:08:03They act like solar panels, absorbing the heat.
0:08:05 > 0:08:09Just beneath the surface, a web of capillaries carries the warm blood
0:08:09 > 0:08:12to the crocodile's core...
0:08:13 > 0:08:16..activating his systems.
0:08:23 > 0:08:26His eyesight sharpens.
0:08:29 > 0:08:32His hearing tunes in to the world around him.
0:08:34 > 0:08:38BIRDS SCREECH
0:08:42 > 0:08:47For the next six months, he must make do with only fish to snack on.
0:09:01 > 0:09:04Then, it is the moment he's been waiting for.
0:09:08 > 0:09:10Inside his ears,
0:09:10 > 0:09:14minute hair-like structures detect a low-frequency sound
0:09:14 > 0:09:17well beyond human hearing.
0:09:23 > 0:09:25It's the rumble of a distant stampede.
0:09:36 > 0:09:39Hordes of wildebeest on their never-ending quest
0:09:39 > 0:09:41for fresh pastures.
0:10:15 > 0:10:18Finally, he has his quarry in his sight.
0:10:20 > 0:10:22The hunt is on.
0:10:26 > 0:10:30While the crocodile can wait for prey to come to him,
0:10:30 > 0:10:35another predator must make an epic journey to reach hers.
0:10:42 > 0:10:44Deep in the Indian Ocean,
0:10:44 > 0:10:49the world's largest predatory fish is heading to her feeding grounds.
0:11:10 > 0:11:15One ton and five metres long, this female great white shark
0:11:15 > 0:11:22left the coast of Australia over 100 days ago on a 7,000-mile journey.
0:11:27 > 0:11:32She cruises half a mile down, in a world of pitch black.
0:11:46 > 0:11:48Up above,
0:11:48 > 0:11:52fishing fleets are scooping out the last of the big shoals.
0:11:59 > 0:12:05Down below, the shark is burning the last of her fuel supply.
0:12:16 > 0:12:19She has almost exhausted the fatty oils in her liver.
0:12:28 > 0:12:31She must get to her feeding grounds soon.
0:12:40 > 0:12:45Highly sophisticated electro-sensors in her nose...
0:12:47 > 0:12:51..allow her to detect the Earth's magnetic grid...
0:12:56 > 0:12:59..and accurately compute her position.
0:13:02 > 0:13:06Occasionally, she returns to the surface,
0:13:06 > 0:13:10possibly to get her bearings from the stars.
0:13:23 > 0:13:28Finally, the near-starving shark reaches her destination,
0:13:28 > 0:13:30the coast of South Africa.
0:13:43 > 0:13:47It's early winter and she has timed her arrival to perfection.
0:13:55 > 0:13:59Thousands of six-month-old Cape fur seals are venturing
0:13:59 > 0:14:02into deep water for the first time.
0:14:08 > 0:14:11Thanks to their energy-rich blubber,
0:14:11 > 0:14:15these seals would make a perfect meal for most sharks.
0:14:23 > 0:14:28But most sharks can't cope with these cold temperatures.
0:14:36 > 0:14:38They're cold-blooded
0:14:38 > 0:14:42and lose body heat as their blood passes through their gills.
0:14:48 > 0:14:50The great white, however,
0:14:50 > 0:14:55uses a specialised network of blood vessels to reabsorb its body heat.
0:15:04 > 0:15:07Because of this, it can raise its body temperature
0:15:07 > 0:15:1114 degrees higher than other sharks,
0:15:11 > 0:15:16giving it superior strength, speed and brain power.
0:15:26 > 0:15:29She's crossed an ocean to be here.
0:15:32 > 0:15:34It's time to eat.
0:15:42 > 0:15:45From two miles away, she can smell the colony,
0:15:47 > 0:15:51able to detect one molecule of blood in a million of water.
0:15:56 > 0:15:59From 250 metres away,
0:15:59 > 0:16:02she can distinguish the sound of seals from the background surf.
0:16:11 > 0:16:14From 25 metres, she can make out surface objects
0:16:14 > 0:16:16only 15 centimetres across.
0:16:23 > 0:16:25The hunt is on!
0:16:41 > 0:16:46While the ultimate sea predator can go without a kill for weeks,
0:16:47 > 0:16:52the ultimate land predator must kill almost every day to survive.
0:16:58 > 0:17:00The fastest animal on land
0:17:00 > 0:17:03has had the run of the African plains for millennia.
0:17:08 > 0:17:11But sometimes speed isn't enough.
0:17:14 > 0:17:16The cheetah.
0:17:25 > 0:17:30So far, this mother has succeeded in keeping her three cubs alive...
0:17:32 > 0:17:36..when typically, only one would reach its first birthday.
0:17:55 > 0:17:58Hyenas.
0:17:58 > 0:18:01They will kill cheetah cubs.
0:18:03 > 0:18:07Not only do they have strength in numbers, they're also bigger,
0:18:07 > 0:18:10with bone-crushing jaws.
0:18:23 > 0:18:28To protect her young, the cheetah must act as a decoy.
0:18:31 > 0:18:34Inside, her body fires into action.
0:18:37 > 0:18:40Adrenalin is quickly flushed into the bloodstream.
0:18:44 > 0:18:48Her huge heart doubles its rate to 250 beats a minute...
0:18:53 > 0:18:57..sending extra oxygen and sugars directly
0:18:57 > 0:18:58to her enormous leg muscles.
0:19:02 > 0:19:05She is now ready to engage the enemy.
0:19:47 > 0:19:50This time, she has won.
0:19:51 > 0:19:54But her cubs are hungry.
0:19:54 > 0:19:57They need meat and milk every day.
0:19:59 > 0:20:02She too is weakening.
0:20:02 > 0:20:05To achieve her killer speed, she carries little fat
0:20:05 > 0:20:08and is constantly on the verge of starvation.
0:20:08 > 0:20:10She must eat.
0:20:14 > 0:20:18Cheetahs have enhanced vision in the horizontal plane...
0:20:18 > 0:20:24and can spot a moving gazelle from over a mile away.
0:20:45 > 0:20:47Approaching downwind, she creeps towards
0:20:47 > 0:20:50her 30-metre striking distance...
0:20:59 > 0:21:01..making the most of her camouflage.
0:21:34 > 0:21:38Once again, there's a chain reaction...
0:21:38 > 0:21:41as she prepares for the fastest chase on land.
0:21:49 > 0:21:52The hunt is on.
0:21:54 > 0:21:56All four predators are poised for the attack.
0:22:00 > 0:22:03Their insides a powder keg...
0:22:03 > 0:22:06just waiting to explode.
0:22:10 > 0:22:15But who will make the kill, and who will go hungry?
0:22:32 > 0:22:36Nature's top gun, the peregrine falcon.
0:22:40 > 0:22:42Desperate to feed her chicks...
0:22:44 > 0:22:49..she locks onto her target, a fast and agile pigeon.
0:22:50 > 0:22:53Time to turn on the speed.
0:22:58 > 0:23:01Tucking in her wings, she shoots towards Earth.
0:23:07 > 0:23:13Her teardrop-shaped body, the height of aerodynamic design.
0:23:16 > 0:23:18Within seconds, she has reached
0:23:18 > 0:23:21her terminal velocity of 200 miles per hour.
0:23:31 > 0:23:34The force of air would explode her lungs,
0:23:34 > 0:23:38if not for the baffles in her nostrils,
0:23:38 > 0:23:42a design so effective it is now used in jet engines.
0:23:55 > 0:23:57Nictating membranes wipe her eyes
0:23:57 > 0:24:00to clear them of debris and stop them drying out.
0:24:04 > 0:24:10She prepares for impact, a manoeuvre requiring split-second timing.
0:24:13 > 0:24:17But the pigeon spotted her...
0:24:17 > 0:24:20and she can't compete on the flat.
0:24:49 > 0:24:54Despite their speed, peregrine falcons have a poor strike rate,
0:24:54 > 0:24:59with only 20% of attacks ending in a kill.
0:25:02 > 0:25:06But her chicks must feed before the day is out.
0:25:20 > 0:25:24Back in Africa, hunger is also preying on the mind
0:25:24 > 0:25:26of the freshwater predator.
0:25:39 > 0:25:44So far, this Nile crocodile has survived on meagre pickings.
0:25:47 > 0:25:51Now is his chance for a proper meal.
0:26:04 > 0:26:07The crocodile is an ambush predator.
0:26:07 > 0:26:10But to succeed, he must get close.
0:26:11 > 0:26:14No more than three metres away.
0:26:35 > 0:26:38The wildebeest are wary of any movement.
0:26:47 > 0:26:51For his final approach, he must vanish completely.
0:27:07 > 0:27:13Although he can barely see, he uses his claws to feel his way forward.
0:27:24 > 0:27:27Pressure receptors studded along his jaws pick up vibrations
0:27:27 > 0:27:29in the water...
0:27:35 > 0:27:37..guiding him to his prey.
0:27:45 > 0:27:49A large crocodile can hide itself in 30 centimetres of water.
0:28:01 > 0:28:04Now, he must wait for them to come to him.
0:28:17 > 0:28:20By lowering his heart rate...
0:28:21 > 0:28:24..and slowing down his metabolism...
0:28:26 > 0:28:29..he can stay submerged for up to two hours.
0:28:39 > 0:28:44Finally, the temptation to drink is too much for the wildebeest.
0:29:11 > 0:29:16He swipes his muscular tail, half his body length.
0:29:17 > 0:29:20It launches him three metres out of the water.
0:29:26 > 0:29:28He shuts his eyes to protect them...
0:29:35 > 0:29:41..and snaps blindly, his jaws studded with five-centimetre fangs.
0:29:57 > 0:29:58He's missed.
0:30:10 > 0:30:12The Nile crocodile's hit rate of 30%
0:30:12 > 0:30:15may beat that of the peregrine falcon...
0:30:18 > 0:30:22..but the wildebeest are only fleeting visitors to his river.
0:30:30 > 0:30:36He must make a kill soon if he is to survive the lean times ahead.
0:30:47 > 0:30:49Drained after an epic voyage,
0:30:49 > 0:30:54the ultimate ocean predator is also ravenous.
0:31:06 > 0:31:10She's come all this way to feast on the thousands of young seals
0:31:10 > 0:31:12braving open water for the first time.
0:31:24 > 0:31:2825 metres down, she launches her lightning strike.
0:31:37 > 0:31:39Three-quarters of her bodyweight
0:31:39 > 0:31:41is muscle that powers her enormous tail.
0:31:56 > 0:32:00Thanks to her fortified scales, her streamlined body
0:32:00 > 0:32:03glides through the water with minimal friction.
0:32:10 > 0:32:14At 31 miles an hour, she's like a living torpedo.
0:32:19 > 0:32:23Moments before the strike, she rolls her eyes back to protect them.
0:32:33 > 0:32:37Steering blind, she now depends on her sixth sense.
0:32:40 > 0:32:45The electro-sensors on her snout detect the seal's electric field.
0:33:01 > 0:33:04Her jaws open almost a metre wide...
0:33:09 > 0:33:13..revealing row upon row of serrated daggers.
0:34:31 > 0:34:37With a 50% hit rate, she is the most efficient hunter so far.
0:34:39 > 0:34:41But she must consume more blubber
0:34:41 > 0:34:44if she's to make it back to peak condition.
0:35:00 > 0:35:02Back on the African plains,
0:35:02 > 0:35:06the fastest land animal is moving in for the kill.
0:35:15 > 0:35:19The survival of her cubs is at stake.
0:35:37 > 0:35:43From 0 to 60 in under three seconds, she outperforms a Porsche.
0:35:45 > 0:35:48Extra-wide airways and outsized lungs
0:35:48 > 0:35:50allow her to take in more oxygen.
0:36:03 > 0:36:08Loose hip and shoulder joints give her extended reach.
0:36:12 > 0:36:15Combined with an elastic spine...
0:36:17 > 0:36:19..that both arches up and curves down.
0:36:23 > 0:36:26This gives her a seven-metre stride.
0:36:29 > 0:36:32For more than half the time, she is airborne.
0:36:41 > 0:36:45Thrusting her forward are her huge leg muscles...
0:36:47 > 0:36:51..composed mainly of fast-twitch fibres
0:36:51 > 0:36:54that contract far quicker than normal muscles...
0:36:56 > 0:37:00..and that run on glycogen, nature's own rocket fuel.
0:37:07 > 0:37:09But there's a catch.
0:37:09 > 0:37:12Glycogen breaks down into lactic acid,
0:37:12 > 0:37:14the poison that causes muscle cramp.
0:37:17 > 0:37:21She has just 20 seconds to make her kill before her muscles burn out.
0:37:23 > 0:37:28Hurtling at 70 miles an hour, she risks everything on a trip.
0:37:55 > 0:37:57With a 50% strike rate,
0:37:57 > 0:38:01the cheetah matches the efficiency of the great white,
0:38:01 > 0:38:05but holding onto her kill will be another matter.
0:38:12 > 0:38:15By strike rate alone, the cheetah...
0:38:17 > 0:38:21..and great white are the top predators.
0:38:23 > 0:38:27Snapping at their heels is the Nile crocodile...
0:38:27 > 0:38:31with the peregrine falcon swooping into fourth.
0:38:33 > 0:38:37But there is more to survival than just hunting.
0:39:02 > 0:39:05The great white has made her first kill
0:39:05 > 0:39:08but she must make up for lost time.
0:39:51 > 0:39:52Kill number two.
0:39:55 > 0:40:02Her liver starts to store its fatty oils, but she still needs more.
0:40:46 > 0:40:48Over the short winter season,
0:40:48 > 0:40:52an experienced shark may catch up to three seals a day.
0:41:01 > 0:41:05Months later, however, the tide has turned.
0:41:05 > 0:41:09The seals are both stronger and cannier.
0:41:14 > 0:41:16While some are still being eaten...
0:41:19 > 0:41:23..most can now run rings around their enemy.
0:41:25 > 0:41:29The shark's incredible metabolism is both a strength and a weakness.
0:41:41 > 0:41:43Like the cheetah, her fast-twitch muscles
0:41:43 > 0:41:48are perfect for short bursts of speed but quickly burn out.
0:42:05 > 0:42:08The exhausted shark gives up.
0:42:11 > 0:42:13But she's done well.
0:42:13 > 0:42:16Her fatty liver has now doubled in size.
0:42:35 > 0:42:39With energy in reserve, she moves on to her next feeding ground...
0:42:43 > 0:42:46..one that may be hundreds of miles away.
0:43:00 > 0:43:04But avoiding the fishing fleets is becoming more difficult.
0:43:13 > 0:43:15Her luck has run out.
0:43:22 > 0:43:25This ruthlessly efficient predator
0:43:25 > 0:43:29has ruled the waves for millions of years,
0:43:29 > 0:43:32but now these waves are ruled by humans.
0:43:51 > 0:43:55So what does the future hold for the other top predators?
0:44:03 > 0:44:07On the African plains, the cheetah has made her kill.
0:44:15 > 0:44:18But the chase has attracted attention...
0:44:26 > 0:44:30..and taken its toll on her body.
0:44:33 > 0:44:38Struggling to recover, her lungs heave at 200 breaths per minute.
0:44:42 > 0:44:45Oxygen races to her aching muscles...
0:44:48 > 0:44:51..breaking down the cramping lactic acid.
0:44:55 > 0:44:58But time is running out.
0:46:01 > 0:46:04This time, the hyenas went for the easy meat.
0:46:06 > 0:46:10But it was meat that the cubs desperately needed.
0:46:14 > 0:46:18In the past, cheetahs could avoid their enemies.
0:46:20 > 0:46:22But now, their grasslands are shrinking
0:46:22 > 0:46:27and being replaced by farmland...
0:46:33 > 0:46:37..where the cheetahs are considered a threat to livestock...
0:46:39 > 0:46:41..and shot.
0:46:45 > 0:46:49She may have had the run of the plains for millennia,
0:46:49 > 0:46:54but in the next 30 years the cheetah may become extinct in the wild.
0:47:30 > 0:47:35Rapid change is sweeping across the African landscape.
0:48:01 > 0:48:06The crocodile's first ambush was a spectacular failure.
0:48:07 > 0:48:10To survive the dry season, he must catch a wildebeest
0:48:10 > 0:48:13in the few weeks they are passing through.
0:48:52 > 0:48:55This time, his jaws find their mark...
0:48:58 > 0:49:03..bringing two tons of pressure to bear on each square inch of flesh.
0:49:11 > 0:49:14At last, he has his prize.
0:49:27 > 0:49:30Rather than fend off the other crocodiles,
0:49:30 > 0:49:34he welcomes them to the feast, unable to dine alone.
0:49:37 > 0:49:43His teeth may be formidable but they are grippers, not carvers.
0:49:43 > 0:49:46Together they perform twisting death rolls
0:49:46 > 0:49:49to rip the flesh into bite-size chunks.
0:50:09 > 0:50:13A croc's stomach can hold over 25 kilos of meat.
0:50:16 > 0:50:20To help him digest the cache before it begins to rot,
0:50:20 > 0:50:23the crocodile has a unique adaptation.
0:50:25 > 0:50:27His heart.
0:50:31 > 0:50:34No other animal has two aortas.
0:50:36 > 0:50:41By closing his right aorta, the main blood supply to his body,
0:50:41 > 0:50:43and opening up his left aorta,
0:50:45 > 0:50:48he can divert the carbon dioxide-rich blood
0:50:48 > 0:50:53that he accumulated during his underwater stake-out
0:50:53 > 0:50:55straight to his stomach.
0:50:57 > 0:51:02The acidic blood produces ten times more stomach acid...
0:51:04 > 0:51:07..to help dissolve the huge chunks of meat.
0:51:19 > 0:51:22The potent solution is then converted to fat
0:51:22 > 0:51:25and stored for the lean times ahead.
0:51:37 > 0:51:40He's made his big kill just in time.
0:51:59 > 0:52:03His world is slowly turning to dust.
0:52:14 > 0:52:16The wildebeest are moving on.
0:52:20 > 0:52:23It's time to escape the furnace.
0:52:53 > 0:52:57He shuts down once more.
0:52:59 > 0:53:04He has only his new fat reserves to see him through to the next rains.
0:53:09 > 0:53:12Thanks to the crocodile's remarkable physiology,
0:53:12 > 0:53:18it has outlived the dinosaurs and survived the ice ages.
0:53:29 > 0:53:34Now, there is every chance it will weather the worsening droughts
0:53:34 > 0:53:37brought on by climate change, too.
0:54:01 > 0:54:04All the predators have challenges ahead.
0:54:06 > 0:54:09But some may fare better than others.
0:54:11 > 0:54:15Like the crocodile, the peregrine's first strike was a miss.
0:54:18 > 0:54:21As her chicks depend on a daily kill...
0:54:23 > 0:54:26..the stakes could not be higher.
0:54:57 > 0:54:58Moments before impact...
0:55:02 > 0:55:06..she unleashes her five-centimetre talons.
0:55:21 > 0:55:25The force of the blow snaps the pigeon's backbone.
0:55:52 > 0:55:56CHICKS CRY
0:56:07 > 0:56:11Today, the hungry chicks get to eat.
0:56:20 > 0:56:22But their parents will have to do this
0:56:22 > 0:56:28every day, twice a day, for a month, if all three chicks are to survive.
0:56:54 > 0:56:58Weeks later, these three rookie predators
0:56:58 > 0:57:00are testament to their parents' perseverance.
0:57:25 > 0:57:30Despite their challenges, and their low strike rate,
0:57:30 > 0:57:34urban peregrines are on the rise.
0:57:38 > 0:57:42Around 30 of the world's fastest animal now soar over London.
0:57:51 > 0:57:56All four predators have incredible inside stories.
0:57:58 > 0:58:01But the real perfect predator
0:58:01 > 0:58:06is the one that can best adapt to a rapidly changing world...
0:58:10 > 0:58:14..and learn to live alongside humankind.
0:58:38 > 0:58:41Subtitles by Red Bee Media Ltd
0:58:41 > 0:58:44Email subtitling@bbc.co.uk