0:00:02 > 0:00:05Dolphins, the cleverest creatures in the ocean.
0:00:05 > 0:00:09They may seem familiar, but their undersea lives are a mystery.
0:00:12 > 0:00:15Spy creatures explore their hidden world...
0:00:16 > 0:00:19..discovering amazing abilities..
0:00:22 > 0:00:24..and strange gatherings -
0:00:24 > 0:00:27revealing their intimate relationships,
0:00:27 > 0:00:29as well as their conflicts.
0:00:30 > 0:00:33Discover the intelligence of these fun-loving creatures...
0:00:36 > 0:00:40..and enter their lives as never before.
0:00:56 > 0:01:00In the sea off Mozambique is a secret world.
0:01:03 > 0:01:06It's home to the bottlenose dolphin,
0:01:06 > 0:01:09the most widespread and best-known dolphin in the world.
0:01:11 > 0:01:14Despite their familiarity, their life below the waves
0:01:14 > 0:01:16is steeped in mystery.
0:01:18 > 0:01:20But all this is about to change.
0:01:24 > 0:01:29For here, even a giant clam is not quite as it seems...
0:01:31 > 0:01:34..and these super-smart dolphins are suitably intrigued.
0:01:36 > 0:01:40They know that this clam is like none they have ever seen before.
0:02:05 > 0:02:09These are nautilus, alien creatures from the deep abyss.
0:02:10 > 0:02:14But these are organisms of a very special kind -
0:02:14 > 0:02:17for their eyes are state-of-the-art cameras.
0:02:24 > 0:02:27Nautilus soon meets the long, probing nose
0:02:27 > 0:02:29that gives these dolphins their name.
0:02:37 > 0:02:40Bottlenose dolphins have excellent eyesight,
0:02:40 > 0:02:42but they have another way to see -
0:02:42 > 0:02:45they can beam sound waves from their forehead...
0:02:49 > 0:02:53..and use the returning echoes to create a picture in sound.
0:02:53 > 0:02:56CLICKING
0:02:58 > 0:03:01This sonar penetrates like an x-ray.
0:03:01 > 0:03:03DOLPHIN SQUEAKS
0:03:05 > 0:03:07There's nothing to eat in here.
0:03:11 > 0:03:13The dolphins are so completely at ease with Spy Nautilus,
0:03:13 > 0:03:17a mother is happy to reveal her own precious secret -
0:03:17 > 0:03:22her newborn baby, just five days old.
0:03:31 > 0:03:34He still bears wrinkles from his time curled up in the womb.
0:03:41 > 0:03:44His mother can stay down for 15 minutes,
0:03:44 > 0:03:47he must breathe every two.
0:03:47 > 0:03:50So, for his first few weeks of life,
0:03:50 > 0:03:52she makes sure he's only a few metres from the surface.
0:03:54 > 0:03:56He has been born into an extended family
0:03:56 > 0:03:59made up of aunts and other females.
0:03:59 > 0:04:02DOLPHINS SQUEAK
0:04:02 > 0:04:04Each dolphin has its own unique signature whistle
0:04:04 > 0:04:06that it uses just like a name.
0:04:09 > 0:04:11The baby will learn these whistles
0:04:11 > 0:04:14and soon recognise each and every dolphin.
0:04:19 > 0:04:20Pod members come and go,
0:04:20 > 0:04:23but their enduring friendships are strengthened by touching
0:04:23 > 0:04:25and tickling each other.
0:04:29 > 0:04:32As well as an underwater version of cuddling.
0:04:42 > 0:04:45For mother and baby, close physical contact
0:04:45 > 0:04:47is an essential part of their relationship.
0:04:51 > 0:04:54For the next two years, they will never be apart.
0:05:00 > 0:05:04Further along the Mozambique coast, another spy creature has appeared.
0:05:06 > 0:05:08This is Spy Turtle.
0:05:11 > 0:05:16He is keeping his beady camera eye on another group of bottlenose -
0:05:16 > 0:05:18this time a pod of males.
0:05:27 > 0:05:30Dolphins are intrigued by this strange but harmless turtle,
0:05:30 > 0:05:33so it can easily film them when they come to the surface.
0:05:35 > 0:05:39It can also watch their activities beneath the waves, as well.
0:05:43 > 0:05:46No other spy creature has such a perfect overview.
0:06:00 > 0:06:04Male dolphins live mostly bachelor lives away from the females
0:06:04 > 0:06:08and their life is sociable and happy-go-lucky.
0:06:08 > 0:06:10Like the female pod, males come and go,
0:06:10 > 0:06:13but there is always a core 'band of brothers'
0:06:13 > 0:06:15who can be friends for life.
0:06:16 > 0:06:18To film their energetic and carefree lifestyle,
0:06:18 > 0:06:21Spy Turtle will have to shift up a gear.
0:06:28 > 0:06:30He does his best to keep up...
0:06:50 > 0:06:52..but he's soon outperformed.
0:07:00 > 0:07:05All dolphins love to leap, but these boy racers love it more than most.
0:07:05 > 0:07:08The best can jump nearly six metres.
0:07:31 > 0:07:33Some can really do it in style.
0:07:45 > 0:07:48Across the world, off the coast of Central America,
0:07:48 > 0:07:50lives an even more energetic dolphin.
0:07:52 > 0:07:54To film their high-speed antics,
0:07:54 > 0:07:57a new and faster spy creature joins the team.
0:08:00 > 0:08:03Spy Dolphin reaches 15 miles per hour
0:08:03 > 0:08:05and also has HD cameras for eyes.
0:08:10 > 0:08:12But he'll have his work cut out,
0:08:12 > 0:08:17these spinner dolphins can easily travel 250 miles in a single day.
0:08:19 > 0:08:22And he soon discovers just why they're called spinners.
0:08:33 > 0:08:36They are curious about Spy Dolphin -
0:08:36 > 0:08:40as they jump, they sneak a peek at their strange travelling companion.
0:08:49 > 0:08:53To film underwater, another super-fast spy creature
0:08:53 > 0:08:54enters the fray.
0:08:58 > 0:09:01Spy Tuna can rapidly infiltrate these dolphins...
0:09:03 > 0:09:06..and use the camera in her mouth to capture the first ever images
0:09:06 > 0:09:08from inside the pod.
0:09:13 > 0:09:16She soon discovers that what Spy Dolphin saw at the surface
0:09:16 > 0:09:18was just the tip of the iceberg.
0:09:18 > 0:09:21DOLPHINS SQUEAK AND CLICK
0:09:26 > 0:09:28Although dolphins normally travel in small groups,
0:09:28 > 0:09:31they sometimes come together in spectacular numbers.
0:09:33 > 0:09:38This is a super pod made up of hundreds upon hundreds of dolphins.
0:09:46 > 0:09:49But it's not Spy Tuna's only revelation.
0:09:53 > 0:09:57She soon discovers just how their extraordinary leaps are performed.
0:10:08 > 0:10:11Rapid beats of the tail provide the power...
0:10:16 > 0:10:19..while twisting starts as they leave the water.
0:10:22 > 0:10:27Sheer muscle drives their spectacular aerial display.
0:10:42 > 0:10:46No other dolphin accomplishes these astonishing corkscrews.
0:10:59 > 0:11:01Back in Mozambique,
0:11:01 > 0:11:04the young dolphin is off on his first adventure.
0:11:14 > 0:11:16Stingrays are a common sight.
0:11:16 > 0:11:19His mother uses warning calls to teach him
0:11:19 > 0:11:21to avoid the sting in their tail.
0:11:24 > 0:11:27But it seems this is not just a passing ray...
0:11:30 > 0:11:32..something far more mysterious is happening.
0:11:38 > 0:11:41The stingrays are gathering together.
0:11:44 > 0:11:46The dolphins join in.
0:11:46 > 0:11:49Their unrivalled knowledge of ocean life tells them
0:11:49 > 0:11:52that this entourage is well worth following.
0:11:57 > 0:12:01Leading them is an extremely rare small-eyed stingray -
0:12:01 > 0:12:03the biggest stingray in the ocean.
0:12:07 > 0:12:11Shadowing the rays are cobia fish.
0:12:11 > 0:12:15These renowned scavengers confirm that a meal is on its way.
0:12:28 > 0:12:31This is the first time such an extraordinary gathering
0:12:31 > 0:12:34of sea creatures has been recorded.
0:12:34 > 0:12:38But to the worldly-wise dolphins it must be a common sight.
0:12:38 > 0:12:40It's an early lesson for the new baby,
0:12:40 > 0:12:42but he'll have to hold his breath.
0:12:46 > 0:12:49He's learning that rays possess a unique skill -
0:12:49 > 0:12:51one that might lead them to a meal.
0:12:56 > 0:13:01On the ray's underside is an array of electrosensors.
0:13:01 > 0:13:04These detect the minute electrical discharges
0:13:04 > 0:13:06given off by other animals -
0:13:06 > 0:13:08even those buried in the sand
0:13:09 > 0:13:11When the ray senses a hidden fish,
0:13:11 > 0:13:14it stops and sucks it into its mouth,
0:13:14 > 0:13:18while all the followers can do is scramble for scraps left behind.
0:13:22 > 0:13:25But dolphins are smarter.
0:13:28 > 0:13:32Having used the rays as guides to the best fishing grounds,
0:13:32 > 0:13:34they then deploy their own super-senses
0:13:34 > 0:13:36to find the buried treasure.
0:13:38 > 0:13:42Their sonar penetrates the sand and bounces off the hidden meals.
0:13:43 > 0:13:47DOLPHIN CLICKS
0:13:51 > 0:13:55The baby has sonar, too, but he's still just trying it out.
0:13:57 > 0:14:00DOLPHINS CLICK AND SQUEAK
0:14:04 > 0:14:07His mother's domed forehead, known as the melon,
0:14:07 > 0:14:10concentrates the sound waves into a beam.
0:14:15 > 0:14:18The returning echoes reveal the shape and type of any hidden fish.
0:14:23 > 0:14:24Some make a dash for it.
0:14:28 > 0:14:30But there's always plenty more fish in the sea.
0:14:32 > 0:14:33She tries again.
0:14:35 > 0:14:38By increasing the speed and intensity of her clicks,
0:14:38 > 0:14:40she can search deeper into the sand.
0:14:42 > 0:14:45And a concentrated blast of sonar can even stun the fish.
0:14:48 > 0:14:51CLICKING
0:14:51 > 0:14:53Success at last!
0:14:57 > 0:15:00It's not a moment too soon for the baby dolphin -
0:15:00 > 0:15:01he's held his breath
0:15:01 > 0:15:04for a record-breaking three and a half minutes!
0:15:07 > 0:15:10He now gets his own reward.
0:15:11 > 0:15:14The milk from his mother's watertight pouch
0:15:14 > 0:15:16is six times richer than cow's milk.
0:15:18 > 0:15:19Reared on this nutritious diet,
0:15:19 > 0:15:22he'll double in size in just one month.
0:15:24 > 0:15:25By shadowing his mother,
0:15:25 > 0:15:28the calf learns hunting methods unique to catching fish
0:15:28 > 0:15:31in his local area.
0:15:31 > 0:15:33Like so many things in a dolphin's life,
0:15:33 > 0:15:36the knowledge that rays are a good guide to a meal
0:15:36 > 0:15:39is handed down from mother to calf.
0:15:42 > 0:15:44And the same intelligent learning
0:15:44 > 0:15:48is also seen among other dolphin pods throughout the world.
0:15:52 > 0:15:54The shallow waters of the Florida Keys
0:15:54 > 0:15:57create a very different challenge for a bottlenose dolphin.
0:15:59 > 0:16:01The way they catch fish is even more inventive.
0:16:05 > 0:16:08It's a perfect mission for Spy Dolphin.
0:16:20 > 0:16:23But he won't be working alone...
0:16:25 > 0:16:28..beneath the waves, a new spy creature
0:16:28 > 0:16:30joins the underwater menagerie.
0:16:54 > 0:16:58Spy Ray, a creature that glides along the bottom
0:16:58 > 0:17:00as it follows the dolphins across the seagrass.
0:17:09 > 0:17:13Its subjects have devised an extraordinary hunting technique
0:17:13 > 0:17:15especially for these conditions.
0:17:20 > 0:17:23It starts when a dolphin deliberately beats his tail
0:17:23 > 0:17:25to stir up a plume of mud...
0:17:33 > 0:17:36..covering the unsuspecting fish...
0:17:36 > 0:17:37as well as Spy Ray.
0:17:43 > 0:17:45He soon forms a U-shaped mud plume.
0:17:53 > 0:17:55And then ploughs through the cloud,
0:17:55 > 0:17:58catching any fish confused by the sudden blackout.
0:18:05 > 0:18:09He's chasing ballyhoos, one of the fastest-reacting fish in the sea.
0:18:14 > 0:18:17But the dolphin's sonar can see right through the mud,
0:18:17 > 0:18:20while the fish can't see her coming.
0:18:25 > 0:18:28Usually, the dolphin wouldn't stand a chance with these fish,
0:18:28 > 0:18:32but by using his intelligence to create a mud screen,
0:18:32 > 0:18:33he regains the advantage.
0:18:37 > 0:18:39Further along the Keys,
0:18:39 > 0:18:43the spy creatures discover that when dolphins cooperate to use the mud,
0:18:43 > 0:18:46they can achieve even more success.
0:18:48 > 0:18:51By working as a team, they have devised a way to hunt mullet.
0:18:53 > 0:18:56One member of the pod races ahead of the shoal,
0:18:56 > 0:18:59and again beats her tail to create a mud wall.
0:19:00 > 0:19:03But this time she creates a complete circle,
0:19:03 > 0:19:05entrapping the fish inside.
0:19:06 > 0:19:10As the mud ring spreads, the mullet try to escape the trap,
0:19:10 > 0:19:13leaping into the mouths of the waiting dolphins.
0:19:18 > 0:19:19Once all of the fish have jumped,
0:19:19 > 0:19:22the dolphins start again, forming a new mud ring.
0:19:28 > 0:19:31The dolphins then wait for the next fish eruption.
0:19:32 > 0:19:36Spy Dolphin noses closer to take up a ringside seat.
0:19:57 > 0:20:01The youngsters learn the art of catching by watching the experts.
0:20:09 > 0:20:11These unique techniques are only
0:20:11 > 0:20:14known by dolphins local to these shallow waters
0:20:14 > 0:20:18and these skills are passed on from generation to generation.
0:20:52 > 0:20:55When they've caught all they need,
0:20:55 > 0:20:57it's a chance to show-off.
0:21:10 > 0:21:13Back in Mozambique, the pod of females are skirting
0:21:13 > 0:21:15the coast, looking for their next meal.
0:21:16 > 0:21:19This time, they are after another local delicacy
0:21:19 > 0:21:22that requires yet another tactic.
0:21:23 > 0:21:26Fish shoals are surprisingly noisy
0:21:26 > 0:21:29and dolphins can hear the sounds they make from ten miles away.
0:21:32 > 0:21:35Nautilus is among the many spy creatures watching
0:21:35 > 0:21:37the dolphins' plan unfurl.
0:21:54 > 0:21:58The youngster is over a month old now and can stay down for longer,
0:21:58 > 0:22:01but diving deep is always a great adventure.
0:22:06 > 0:22:09They are hunting huge kingfish.
0:22:09 > 0:22:12Some reach over a metre and weigh 15 kilos.
0:22:12 > 0:22:15They are far from easy to catch.
0:22:17 > 0:22:20The young dolphin is still only an observer,
0:22:20 > 0:22:23but this is how he learns the skills needed later in life.
0:22:23 > 0:22:25DOLPHINS CLICK
0:22:30 > 0:22:32The dolphins take their time.
0:22:32 > 0:22:36They know they can't outpace the kingfish, so their idea is to scan
0:22:36 > 0:22:41each fish with sonar and select only the weakest, slowest individuals.
0:22:55 > 0:22:58DOLPHINS CLICK
0:23:02 > 0:23:04And there it is!
0:23:04 > 0:23:07She's found her target and gives chase.
0:23:16 > 0:23:18It's a big catch.
0:23:18 > 0:23:21A nursing mother must eat 15 kilos of fish a day,
0:23:21 > 0:23:26so just one kingfish can provide all her daily requirements.
0:23:29 > 0:23:31She heads back to the depths.
0:23:33 > 0:23:37And Spy Ray soon discovers the reason.
0:23:38 > 0:23:40They use the seabed to help
0:23:40 > 0:23:43break the fish into smaller pieces.
0:23:44 > 0:23:49It's another new discovery for the spy creatures.
0:23:49 > 0:23:51But more revelations are in store.
0:23:53 > 0:23:58Killing such big fish has unexpected consequences.
0:23:58 > 0:24:00The parasites of their prey have jumped ship
0:24:00 > 0:24:03and attached themselves to the dolphins.
0:24:04 > 0:24:08Even the young dolphin has acquired an unwelcome hitchhiker
0:24:08 > 0:24:10just beneath his eye.
0:24:13 > 0:24:16It's a remora - a suckerfish that lives by
0:24:16 > 0:24:18eating the dolphin's leftovers.
0:24:19 > 0:24:23They skip around like an aquatic fly.
0:24:24 > 0:24:26But they're even more irritating than a gnat,
0:24:26 > 0:24:28and far harder to get rid of.
0:24:31 > 0:24:33The dolphins know a few tricks.
0:24:33 > 0:24:36Using the seabed to scrub them off is a good start.
0:24:40 > 0:24:43The youngster has a go.
0:24:53 > 0:24:55Then tries again.
0:24:59 > 0:25:01But, whatever he does,
0:25:01 > 0:25:03the pesky remora stays on board.
0:25:11 > 0:25:13Even when he has to take a breath.
0:25:18 > 0:25:20He tries a different tack,
0:25:20 > 0:25:23rubbing it against an unsuspecting dolphin.
0:25:25 > 0:25:27But has better luck with his mum!
0:25:29 > 0:25:33She accepts the unwelcome gift, as only a mother can!
0:25:39 > 0:25:41Back in the Pacific Ocean,
0:25:41 > 0:25:45the spy cameras are finding that the spinners' extraordinary leaps
0:25:45 > 0:25:48might help them deal with their own remora problem.
0:25:59 > 0:26:02As a spinner leaps, it's clear that she too
0:26:02 > 0:26:05has a remora attached to her belly.
0:26:08 > 0:26:11By twisting violently, she makes it hard
0:26:11 > 0:26:13for any hangers-on to stay on board.
0:26:14 > 0:26:18Most spinning dolphins have these unwelcome guests
0:26:18 > 0:26:21and it's likely that many are dislodged on impact.
0:26:28 > 0:26:30But they leap so persistently,
0:26:30 > 0:26:32there must be other reasons too.
0:26:36 > 0:26:38Possibly, it's a long distance signal
0:26:38 > 0:26:40that helps keep the pod together.
0:26:47 > 0:26:50But dolphins turn everything into a game
0:26:50 > 0:26:53and spinning soon becomes a competition.
0:27:33 > 0:27:36Practice starts at an early age.
0:27:39 > 0:27:41A cautious start...
0:27:45 > 0:27:48Then a spectacular leap, but without the spinning.
0:27:51 > 0:27:53Getting better...
0:27:56 > 0:27:58Better still...
0:28:00 > 0:28:02This is more like it!
0:28:05 > 0:28:08Finally, a jump to be proud of!
0:28:10 > 0:28:12It's a perfect ten.
0:28:26 > 0:28:28Meanwhile, in Mozambique,
0:28:28 > 0:28:33the boy racers have turned leaping into a new and dangerous game...
0:28:33 > 0:28:35..playing chicken with a supertanker.
0:28:35 > 0:28:37TANKER HORN BELLOWS
0:28:42 > 0:28:46The huge bow wave offers a free ride with almost no effort at all.
0:28:49 > 0:28:54They go out of their way to play in this man-made surf.
0:28:54 > 0:28:56DOLPHIN WHISTLES
0:29:16 > 0:29:19But all good things must come to an end.
0:29:22 > 0:29:24As Spy Turtle discovers,
0:29:24 > 0:29:27this band of brothers have plenty more ways to entertain themselves.
0:29:38 > 0:29:43Naturally, a favourite pastime involves chasing the opposite sex.
0:29:43 > 0:29:45DOLPHIN CLICKS
0:29:49 > 0:29:53But their boisterous arrival is a dangerous time for a baby.
0:30:03 > 0:30:07A gang of lusty males can kill a young calf
0:30:07 > 0:30:08if he gets in their way.
0:30:11 > 0:30:14And one male gets perilously close to the baby.
0:30:14 > 0:30:16DOLPHINS SQUEAL
0:30:18 > 0:30:20The mother shepherds him away,
0:30:20 > 0:30:24while other females create a protective wall with their bodies.
0:30:27 > 0:30:29The rest confront the males as the baby vanishes
0:30:29 > 0:30:31behind a dolphin blockade.
0:30:35 > 0:30:39Knowing he's safe, his bodyguards return to face the males.
0:30:39 > 0:30:40DOLPHINS CLICK
0:30:44 > 0:30:46Their scars are testament to previous fights.
0:30:49 > 0:30:51DOLPHINS SQUEAL NOISILY
0:30:58 > 0:31:02As always, the spy creatures are right in the thick of it.
0:31:06 > 0:31:10They are simply spectators but, as the females get the upper hand,
0:31:10 > 0:31:14the spy creatures become a soft target for the males.
0:31:17 > 0:31:20They soon run rings round Spy Turtle.
0:31:32 > 0:31:36And Nautilus gets some unwelcome attention.
0:31:42 > 0:31:43Very unwelcome!
0:31:57 > 0:31:59But Turtle is made of sterner stuff
0:31:59 > 0:32:02and he keeps filming as the males are sent packing.
0:32:05 > 0:32:08While Nautilus is out for the count.
0:32:12 > 0:32:15Calm returns to the female pod
0:32:15 > 0:32:18and the baby is safe once more.
0:32:18 > 0:32:19DOLPHIN SQUEALS
0:32:24 > 0:32:27With Nautilus out of action,
0:32:27 > 0:32:31it's time for a new spy creature to take on the feisty males.
0:32:31 > 0:32:36Spy Squid is perfectly suited to explore the coral reefs.
0:32:39 > 0:32:41Like all the spy creatures,
0:32:41 > 0:32:44his success relies on the dolphins' innate curiosity.
0:32:46 > 0:32:48DOLPHINS WHISTLE
0:33:03 > 0:33:05And, like a real squid,
0:33:05 > 0:33:07he creates a jet of water to get around.
0:33:13 > 0:33:15Using this jet propulsion,
0:33:15 > 0:33:18he explores a reef that's a popular spot for the male dolphins.
0:33:22 > 0:33:26Why they come here has always been a mystery.
0:33:33 > 0:33:36But the squid soon discovers that they use the coral reef
0:33:36 > 0:33:38as an impromptu health spa.
0:33:40 > 0:33:42Favourite coral heads are used like pumice stones,
0:33:42 > 0:33:45helping to shed off old skin.
0:33:48 > 0:33:52They visit the same chosen scrubbing sites time and again.
0:34:00 > 0:34:04Incredibly, dolphins replace their outer layer of skin
0:34:04 > 0:34:06once every three hours.
0:34:06 > 0:34:09It's vital for an animal where streamlining is everything.
0:34:16 > 0:34:20By rubbing against the coral, they help speed up the process.
0:34:29 > 0:34:32It's the ultimate way to exfoliate!
0:34:39 > 0:34:41After a good scrub and a scratch,
0:34:41 > 0:34:43the dolphins move on.
0:34:44 > 0:34:47But Spy Squid has attracted the attention of some
0:34:47 > 0:34:49less friendly reef dwellers.
0:34:50 > 0:34:53Potato cod are nearly six feet long
0:34:53 > 0:34:55and weigh over 100kgs.
0:34:59 > 0:35:01And they eat squid for breakfast!
0:35:11 > 0:35:13Spy Squid is dicing with death.
0:35:24 > 0:35:26Time for a sharp exit.
0:35:37 > 0:35:40Meanwhile, the male dolphins have found yet more
0:35:40 > 0:35:43ways of occupying their overactive minds.
0:35:48 > 0:35:52Africa's southern coastline is renowned for its huge breakers
0:35:52 > 0:35:55and whenever surf's up, it's the perfect time for the dolphins
0:35:55 > 0:35:57to catch a wave.
0:36:01 > 0:36:02Being so intelligent,
0:36:02 > 0:36:05dolphins like to keep themselves fully occupied.
0:36:08 > 0:36:12Unlike most animals, much of what they do is simply for fun.
0:36:17 > 0:36:18Like experienced surfers,
0:36:18 > 0:36:21the dolphins know that timing is everything.
0:36:35 > 0:36:38They turn in perfect synchrony.
0:37:26 > 0:37:29Squid finally catches up and goes for the ride of its life.
0:37:46 > 0:37:51But even for dolphins, the waves are sometimes just too challenging.
0:37:57 > 0:38:00And for the Squid, it's total wipe out!
0:38:11 > 0:38:13Among the nearby female pod,
0:38:13 > 0:38:18the young dolphin is now over six months old.
0:38:18 > 0:38:21He'll keep suckling until he's nearly fully grown
0:38:21 > 0:38:23and ready to leave his mother.
0:38:25 > 0:38:29He's a bundle of energy and just loves to play and leap.
0:38:40 > 0:38:44But, at this age, lessons are starting to get serious.
0:38:48 > 0:38:50One of the first was how to catch fish.
0:38:50 > 0:38:53Now he must learn to do it on his own.
0:38:53 > 0:38:57He must master using his sonar to locate food hidden in the sand.
0:39:04 > 0:39:08He's an attentive student, mirroring his mother's every move.
0:39:11 > 0:39:15DOLPHINS CLICK
0:39:23 > 0:39:27But mastering his sonar isn't exactly child's play.
0:39:27 > 0:39:32A misfire will give the game away and scare off the fish.
0:39:32 > 0:39:35DOLPHIN SQUEALS
0:39:35 > 0:39:37Missed!
0:39:42 > 0:39:47Eventually, he gets the knack and his much deserved reward.
0:39:52 > 0:39:54He will need these skills when, at two years old,
0:39:54 > 0:39:58he will finally leave the maternal group to set up life outside.
0:40:04 > 0:40:08Back with the spinners, Spy Turtle joins the other spy creatures.
0:40:19 > 0:40:22As the pod passes, he's completely surrounded.
0:40:25 > 0:40:28A super-pod like this can be over half a mile long.
0:40:33 > 0:40:36Down below, Tuna is suffering the consequences
0:40:36 > 0:40:39of being in the heart of the action.
0:40:43 > 0:40:45Dolphins consume a lot of fish
0:40:45 > 0:40:48and the result is a lot of waste.
0:40:51 > 0:40:55But for dolphins, pooing on your friends is socially acceptable.
0:40:57 > 0:40:58It's full of pheromones,
0:40:58 > 0:41:02giving information about the state and mood of other dolphins,
0:41:02 > 0:41:04as well as the food they've just eaten!
0:41:06 > 0:41:09It's all too easy to take a direct hit!
0:41:16 > 0:41:18This is actually a complement.
0:41:18 > 0:41:21She really is a dolphin-friendly tuna!
0:41:25 > 0:41:27Out of the firing line,
0:41:27 > 0:41:31Turtle is still having a bit of trouble keeping up.
0:41:32 > 0:41:34He valiantly does his best.
0:41:34 > 0:41:37But when they really press the accelerator,
0:41:37 > 0:41:38there is nothing he can do.
0:42:11 > 0:42:14Tuna isn't so easily outclassed
0:42:14 > 0:42:16and she soon spies why the spinners are so excited.
0:42:20 > 0:42:23Bubbles stream from the spinner's blowholes,
0:42:23 > 0:42:26showing that the dolphins are whistling out their names.
0:42:26 > 0:42:28DOLPHINS WHISTLE
0:42:29 > 0:42:31These signature whistles
0:42:31 > 0:42:33fill the ocean with glistening speech bubbles.
0:42:39 > 0:42:43It's a magical sight that has never been filmed before.
0:42:49 > 0:42:50But the wonders continue,
0:42:50 > 0:42:54as the reason for their excitement becomes clear.
0:42:54 > 0:42:56Another super-pod is approaching.
0:43:00 > 0:43:01DOLPHIN WHISTLES CONTINUE
0:43:05 > 0:43:08Incredibly, the two groups start to combine.
0:43:14 > 0:43:16The numbers grow and grow,
0:43:16 > 0:43:21until they form the greatest dolphin gathering ever seen.
0:43:29 > 0:43:32This is the legendary megapod,
0:43:32 > 0:43:35made up of over 3,000 dolphins!
0:43:48 > 0:43:52Never have so many dolphins been filmed in one underwater view.
0:43:52 > 0:43:56It looks more like a vast fish shoal than a pod of dolphins!
0:44:02 > 0:44:05Dolphins can only reach these numbers in the deep ocean
0:44:05 > 0:44:07where vast fish shoals can be found.
0:44:12 > 0:44:16Here, the ocean bottom lies 3,000 metres down.
0:44:21 > 0:44:26At the surface, Spy Turtle has only just managed to catch up!
0:44:29 > 0:44:34Below, the new arrivals start to get to know each other
0:44:34 > 0:44:37and romance blossoms everywhere.
0:44:39 > 0:44:43Unlike the bottlenose, they appear to be meeting in peaceful harmony.
0:45:04 > 0:45:08In the megapod, it seems, free love reigns.
0:45:12 > 0:45:16And, as Turtle discovers, love, indeed, is all around.
0:45:18 > 0:45:23A pair of olive ridley turtles are also caught up in the romantic mood.
0:45:36 > 0:45:41The male clasps his mate using special claws on his flippers.
0:45:44 > 0:45:48But, while he's on board, the female is firmly in the driving seat.
0:45:58 > 0:46:01And when she shows an interest in Spy Turtle,
0:46:01 > 0:46:03there is simply nothing he can do.
0:46:05 > 0:46:09Unfortunately for him, she seems to prefer Spy Turtle!
0:46:22 > 0:46:26She strokes his face to show her interest.
0:46:37 > 0:46:40But Spy Turtle has a job to do,
0:46:40 > 0:46:43he's here only to observe.
0:46:44 > 0:46:46He leaves them to it.
0:46:48 > 0:46:51The natural order is restored once more.
0:46:56 > 0:46:58There's always more dolphins to film.
0:47:04 > 0:47:07Back in Mozambique, Spy Squid is also on duty.
0:47:11 > 0:47:14He soon discovers that the male bottlenose are also
0:47:14 > 0:47:16in a playful mood.
0:47:18 > 0:47:20Pieces of seaweed and other trinkets,
0:47:20 > 0:47:22plucked from the ocean floor
0:47:22 > 0:47:24often become treasured possessions.
0:47:24 > 0:47:26DOLPHINS SQUEAL
0:47:36 > 0:47:39The more interesting they are, the better.
0:47:44 > 0:47:47And wafting fronds of Sargassum seaweed
0:47:47 > 0:47:49are the most sought after of all.
0:47:53 > 0:47:56They delight in gathering and carrying them.
0:48:00 > 0:48:02And showing off their catching skills.
0:48:07 > 0:48:12But today these seaweed garlands have another purpose.
0:48:17 > 0:48:22The males carry them like floral bouquets towards the females.
0:48:26 > 0:48:28The females react as before,
0:48:28 > 0:48:31confronting the males with a show of strength.
0:48:37 > 0:48:39The youngster may now be over a year old
0:48:39 > 0:48:41but his mother still shepherds him away.
0:48:41 > 0:48:44It's better to be safe than sorry.
0:48:45 > 0:48:47But something has changed,
0:48:47 > 0:48:49the males have come bearing gifts
0:48:49 > 0:48:52and their plan seems to be working.
0:48:52 > 0:48:55A male with a bouquet catches the eye of a young female...
0:48:57 > 0:48:59..and he shows off his skills.
0:49:14 > 0:49:16She seems impressed.
0:49:20 > 0:49:22He drops the bouquet...
0:49:26 > 0:49:28..and she catches it.
0:49:35 > 0:49:37It's now her turn to flirt,
0:49:37 > 0:49:40using the garland to tempt and tease.
0:49:46 > 0:49:51They may now be an item, but they won't spend much time alone.
0:49:57 > 0:49:59His mates muscle in
0:49:59 > 0:50:01and the female is spoilt for choice.
0:50:10 > 0:50:13No other mammal uses gifts in this way.
0:50:13 > 0:50:17It's another demonstration of their superior intelligence
0:50:17 > 0:50:19and refined social skills.
0:50:26 > 0:50:28The two may have planned to be alone,
0:50:28 > 0:50:32but among bottlenose, mating is rarely a private affair.
0:50:35 > 0:50:37Even the mother is swept up in the flirtatious mood.
0:50:53 > 0:50:56Although she won't be ready to breed until her boy leaves home.
0:50:59 > 0:51:03Back in the Pacific Ocean, Spy Tuna is on her final mission
0:51:03 > 0:51:05with the spinner dolphins.
0:51:07 > 0:51:10She soon discovers another extraordinary example
0:51:10 > 0:51:13of a dolphin's co-operation and intelligence.
0:51:15 > 0:51:17Super-pods like these march on their stomachs
0:51:17 > 0:51:20and, 30 miles from shore,
0:51:20 > 0:51:22the deep ocean seldom disappoints.
0:51:24 > 0:51:28Their long range sonar has detected something down below.
0:51:31 > 0:51:33A shoal of lanternfish ascending from the deep.
0:51:37 > 0:51:40By day, these fish normally live 1,000 metres down,
0:51:40 > 0:51:42so this is a rare sight indeed.
0:51:44 > 0:51:47Plans are quickly made
0:51:47 > 0:51:50and the spinners start by pushing the fish closer to the surface.
0:51:52 > 0:51:54As the dolphins hug the outside edge,
0:51:54 > 0:51:58the fish react, as planned, by moving upwards as a mass.
0:52:00 > 0:52:03More spinners add to the upward pressure.
0:52:07 > 0:52:10The huge shoal is gradually squeezed closer together.
0:52:16 > 0:52:17The spinners keep up the pressure,
0:52:17 > 0:52:19pushing the fish towards the surface
0:52:19 > 0:52:21and into an ever tighter mass.
0:52:32 > 0:52:34The swirling shoal has nowhere to go...
0:52:36 > 0:52:38..now the feeding begins.
0:52:42 > 0:52:45The dolphins pick off any stragglers one by one.
0:52:45 > 0:52:48It requires hardly any effort at all.
0:52:56 > 0:52:59DOLPHINS CLICK
0:53:05 > 0:53:10But in the ocean, a feast is rarely kept secret for long.
0:53:16 > 0:53:20These are giant Mobula rays,
0:53:20 > 0:53:22each with a wingspan of over two metres.
0:53:29 > 0:53:32They simply open their bucket-sized mouths
0:53:32 > 0:53:35and scoop up a super-sized meal.
0:53:35 > 0:53:38Dozens of fish disappear in a flash.
0:53:48 > 0:53:49But this isn't their only trick,
0:53:49 > 0:53:52their huge wings flick like a whip,
0:53:52 > 0:53:56stunning or killing dozens of fish with every pass.
0:53:57 > 0:54:00The following rays will trawl up the victims
0:54:00 > 0:54:02and, in turn, their wing beats
0:54:02 > 0:54:03create even more carnage.
0:54:08 > 0:54:12The spinners won't turn down a second course,
0:54:12 > 0:54:15especially one handed to them on a plate.
0:54:22 > 0:54:25And yet more rays keep coming.
0:54:40 > 0:54:42Together the spinners and the rays work the shoal
0:54:42 > 0:54:45until every stomach is full.
0:54:45 > 0:54:48Even so, they hardly dent its numbers.
0:54:51 > 0:54:54Lanternfish are the most numerous fish in the deep ocean.
0:54:54 > 0:54:58By fishing so far from land, the spinners and rays gain
0:54:58 > 0:55:01a rare and sumptuous meal.
0:55:16 > 0:55:18Then, as silently as they arrived,
0:55:18 > 0:55:20the rays are gone,
0:55:20 > 0:55:22leaving the dolphins to their games.
0:55:27 > 0:55:28Having eaten all they can,
0:55:28 > 0:55:31the spinners celebrate as only they know how.
0:55:33 > 0:55:35They party way into the night.
0:56:00 > 0:56:02SPLASHING
0:56:36 > 0:56:39Back in Mozambique, the young male bottlenose
0:56:39 > 0:56:41is now growing increasingly independent.
0:56:45 > 0:56:47He has learnt to succeed as a dolphin
0:56:47 > 0:56:49by being curious about everything.
0:57:01 > 0:57:04And when Spy Clam produces a trail of bubbles,
0:57:04 > 0:57:06he's instantly captivated.
0:57:09 > 0:57:11DOLPHIN SQUEALS
0:57:11 > 0:57:14Dolphins test everything with their mouths
0:57:14 > 0:57:18but he soon discovers that bubbles vanish as soon as they are touched.
0:57:34 > 0:57:37Another young friend can't resist having a go.
0:57:37 > 0:57:40Irrepressible curiosity and constant learning
0:57:40 > 0:57:43all adds to their exceptional intelligence.
0:57:49 > 0:57:52It's now time to move on.
0:57:52 > 0:57:54There's plenty more fun to be had in the ocean.
0:57:56 > 0:57:59Especially as a new stage of life is just beginning
0:57:59 > 0:58:01for the young bottlenose,
0:58:01 > 0:58:04an exciting time of independence.
0:58:05 > 0:58:09Next time, find out what happens as he sets off alone.
0:58:11 > 0:58:13Step into the world of the orca,
0:58:13 > 0:58:16the greatest dolphin in the ocean
0:58:16 > 0:58:17and take the ride of your life
0:58:17 > 0:58:20on the back of a real life spy dolphin.
0:58:20 > 0:58:23Uncover more mysteries of the dolphin's secret lives
0:58:23 > 0:58:25and discover what happens
0:58:25 > 0:58:30when one of the spy creatures finally pushes his luck too far!