0:00:03 > 0:00:04Dolphins.
0:00:04 > 0:00:06The cleverest creatures in the ocean.
0:00:06 > 0:00:10Spy creatures delve into their secret lives...
0:00:13 > 0:00:17..to reveal new, surprising behaviour...
0:00:21 > 0:00:24And yet more mysterious events.
0:00:25 > 0:00:30Encounter the greatest dolphin in the ocean.
0:00:30 > 0:00:33And discover their family secrets.
0:00:35 > 0:00:38Hitch a ride on the back of a dolphin.
0:00:39 > 0:00:42And take a leap into another world.
0:00:53 > 0:00:57In South Africa, a superpod of common dolphins is on the move.
0:01:07 > 0:01:11Spy Dolphin joins them and films from the camera in its eye.
0:01:17 > 0:01:20The dolphins are after a special meal,
0:01:20 > 0:01:23one only served up at this time of year.
0:01:23 > 0:01:27CLICKING AND WHISTLING
0:01:38 > 0:01:40The feast happens every winter,
0:01:40 > 0:01:43but in the vast ocean it's difficult to find.
0:01:47 > 0:01:49To track it down,
0:01:49 > 0:01:51they must work as a team.
0:01:51 > 0:01:54CLICKING AND WHISTLING
0:02:04 > 0:02:08Speed is everything. They must beat other predators to the meal.
0:02:13 > 0:02:17By working together, they gain the advantage.
0:02:20 > 0:02:25And here it is, the greatest fish migration on the planet.
0:02:29 > 0:02:31The sardines may number millions,
0:02:31 > 0:02:34but to catch them they must still work as a team.
0:02:37 > 0:02:39CLICKING AND WHISTLING
0:02:39 > 0:02:42They dive deep beneath the shoal
0:02:42 > 0:02:44and start to herd it upwards.
0:02:52 > 0:02:55The fish stick together for safety.
0:02:55 > 0:03:00The dolphins' task is to break down their defences.
0:03:05 > 0:03:08CLICKING AND WHISTLING
0:03:08 > 0:03:11They use loud calls and bursts of bubbles
0:03:11 > 0:03:13to help drive them.
0:03:22 > 0:03:27The shoal fragments into more manageable bait balls.
0:03:27 > 0:03:29Now the feeding begins.
0:03:37 > 0:03:40But sardines are never eaten alone.
0:03:44 > 0:03:47Gannets have been watching from above.
0:03:47 > 0:03:48They seize the moment.
0:03:52 > 0:03:54CLICKING AND WHISTLING
0:04:08 > 0:04:11Gannets aren't the only gate-crashers.
0:04:12 > 0:04:14Bronze whaler sharks join the party.
0:04:40 > 0:04:43The dolphins wisely beat a retreat,
0:04:43 > 0:04:45just in the nick of time.
0:04:48 > 0:04:51A 13-metre Bryde whale.
0:05:06 > 0:05:10And he's not the only ocean giant attracted by the gathering.
0:05:13 > 0:05:16The world's largest dolphin is here, too.
0:05:18 > 0:05:20The orca.
0:05:29 > 0:05:32Orcas always travel as a family,
0:05:32 > 0:05:34and they, too, rely on teamwork.
0:05:34 > 0:05:37ORCAS WHINE
0:05:37 > 0:05:40But they aren't after the sardines.
0:05:40 > 0:05:42They're here for the dolphins.
0:05:59 > 0:06:01They dive deep to take them by surprise.
0:06:09 > 0:06:11A close shave for the dolphin,
0:06:11 > 0:06:14and a disappointment for the orcas.
0:06:16 > 0:06:18But, working as a family,
0:06:18 > 0:06:20they will gain plenty more chances.
0:06:24 > 0:06:26In neighbouring Mozambique,
0:06:26 > 0:06:29Spy Turtle is following a pod of bottlenose.
0:06:33 > 0:06:36He's one of many different spy creatures
0:06:36 > 0:06:38who have been watching how these dolphins
0:06:38 > 0:06:40work together as a team.
0:06:41 > 0:06:43SPY TUNA WHIRS MECHANICALLY
0:06:44 > 0:06:47DOLPHINS CLICK AND WHISTLE
0:06:49 > 0:06:52Spy Baby joins the underwater menagerie.
0:06:53 > 0:06:56This new, remote-controlled spy creature
0:06:56 > 0:06:58also has cameras for eyes.
0:07:00 > 0:07:04He's on the trail of a young male that has just left his mother's pod.
0:07:11 > 0:07:16He's having to survive without the support of family or friends,
0:07:16 > 0:07:20and it's not something he likes very much.
0:07:23 > 0:07:25He unearths a tubeworm...
0:07:25 > 0:07:28Not the quality of seafood he's used to!
0:07:28 > 0:07:31CLICKING
0:07:33 > 0:07:35He's in need of company,
0:07:35 > 0:07:38and for now the new spy creature will do nicely.
0:07:38 > 0:07:41CLICKING AND WHISTLING
0:07:43 > 0:07:46Spy Baby records his lonely call...
0:07:46 > 0:07:50CLICKING AND WHISTLING
0:07:50 > 0:07:52Then plays it back to him.
0:07:52 > 0:07:55CLICKING AND WHISTLING
0:08:00 > 0:08:03The dolphin responds with his signature whistle.
0:08:03 > 0:08:06DOLPHIN WHISTLES
0:08:11 > 0:08:13And Spy Baby plays this back as well.
0:08:14 > 0:08:16SPY BABY WHISTLES
0:08:21 > 0:08:23These unique whistles are used like names,
0:08:23 > 0:08:26repeating the call is a sign of friendship.
0:08:32 > 0:08:35He picks up a mangrove seed...
0:08:36 > 0:08:38..and presents it to Spy Baby.
0:08:41 > 0:08:43It's another friendly gesture.
0:08:48 > 0:08:50Offering gifts is common among dolphins
0:08:50 > 0:08:53but Spy baby can never be the companion he needs.
0:09:08 > 0:09:12He must find real dolphins if he is to thrive in this new stage of life.
0:09:14 > 0:09:17To discover more about the single dolphins,
0:09:17 > 0:09:19the spy team enlists some special support.
0:09:23 > 0:09:24In the Caribbean,
0:09:24 > 0:09:28there is a bottlenose dolphin with a very useful talent.
0:09:41 > 0:09:45He's happy to carry tiny cameras into the wild.
0:09:45 > 0:09:51Each day, this tame dolphin is given free rein to explore the open ocean.
0:09:58 > 0:10:02He returns when he wishes with a recording of his adventures.
0:10:09 > 0:10:10From this unique position,
0:10:10 > 0:10:14it's clear how he glides through the water with such ease.
0:10:25 > 0:10:28Powerful beats of his tail give him perfect control
0:10:28 > 0:10:30as he searches for company.
0:10:35 > 0:10:38But another dolphin finds him first.
0:10:44 > 0:10:46He could hear his call from 10 miles away.
0:10:47 > 0:10:51By happily swimming side-by-side, they show they're friends.
0:11:00 > 0:11:03Only dolphins that know each other come this close.
0:11:08 > 0:11:11They partner up as they start looking for a meal.
0:11:16 > 0:11:19Despite the wealth of fish life on the reef,
0:11:19 > 0:11:21the dolphin has learnt to be choosy
0:11:21 > 0:11:24as many fish are distasteful or poisonous.
0:11:39 > 0:11:44Up ahead is a barracuda - a wholesome meal.
0:11:54 > 0:11:58But it's quick and has a nasty nip. It's not worth the trouble.
0:12:08 > 0:12:12A giant snapper presents the next opportunity.
0:12:14 > 0:12:17But it too is armed to the teeth and best avoided.
0:12:23 > 0:12:27Surprisingly, the barren sea bed offers the easiest possibilities.
0:12:31 > 0:12:34He scans it with sonar, moving his head like a minesweeper.
0:12:57 > 0:13:01When he finds a hidden fish, he IDs it by upping the sonar's intensity.
0:13:08 > 0:13:10A tasty titbit for all the effort.
0:13:13 > 0:13:15Single dolphins have to rely on their personal skills
0:13:15 > 0:13:17and abilities for everything.
0:13:18 > 0:13:24It's a different matter for those that hunt as a pod.
0:13:24 > 0:13:29In South Carolina, bottlenose take teamwork to a whole new level.
0:13:34 > 0:13:36The results are spectacular.
0:13:40 > 0:13:41Fish explode onto the shore.
0:13:45 > 0:13:47They just have to be plucked from the mud.
0:13:55 > 0:13:58Spy Dolphin moves in for a closer look.
0:14:02 > 0:14:07He follows as the dolphins patrol the shallow creeks to find yet more fish shoals.
0:14:12 > 0:14:15The technique requires close cooperation.
0:14:21 > 0:14:24But one dolphin makes the final decision,
0:14:24 > 0:14:26selecting which mud bank to use.
0:14:33 > 0:14:35He then leads the charge.
0:14:39 > 0:14:42The fish leap and panic, right onto the shore.
0:14:59 > 0:15:02The dolphins may hunt like this 15 times on each low tide.
0:15:15 > 0:15:18These techniques are only known by a few local individuals
0:15:18 > 0:15:22and they have to be learnt by younger members of the group.
0:15:27 > 0:15:29Stranding is a serious hazard for dolphins.
0:15:32 > 0:15:34But these have mastered the knack.
0:15:42 > 0:15:46As dolphins are so intelligent, they can tailor the way they catch food
0:15:46 > 0:15:48to exploit specific local conditions.
0:16:53 > 0:16:54In Mozambique,
0:16:54 > 0:16:58the dolphin that's left his pod still cuts a lonely figure.
0:17:07 > 0:17:10His task now is to find a companion.
0:17:11 > 0:17:14And Spy Baby doesn't measure up to the job.
0:17:27 > 0:17:30But Spy Baby soon spots someone who might.
0:17:35 > 0:17:36But it's not a bottlenose.
0:17:41 > 0:17:46It's a rare humpback dolphin - a different species entirely.
0:17:53 > 0:17:57Regardless, the young bottlenose still seems interested.
0:18:01 > 0:18:05And something extraordinary appears to be happening -
0:18:05 > 0:18:08they seem to be making friends.
0:18:13 > 0:18:18This is the first time such a peculiar partnership has ever been filmed.
0:18:27 > 0:18:31They strengthen their relationship by swimming close together.
0:18:35 > 0:18:39It may not be a match made in heaven but at least it's company.
0:18:50 > 0:18:52Orcas are never lonely.
0:18:52 > 0:18:54Their families stay together for life.
0:19:05 > 0:19:10British Columbia has among the highest number of orca pods in the world.
0:19:15 > 0:19:17The family is led by the eldest female,
0:19:17 > 0:19:20while her daughters and granddaughters follow behind.
0:19:29 > 0:19:32Unlike most dolphins, the males stay with their family.
0:19:35 > 0:19:38His dorsal fin is nearly 2m high.
0:19:45 > 0:19:47They stay together for life
0:19:47 > 0:19:51and any hunting knowledge gained is kept exclusively within the group.
0:19:54 > 0:19:58A calf learns the family secrets from an early age.
0:19:58 > 0:20:00What he knows depends on which pod he's in.
0:20:05 > 0:20:08This pod specialises in hunting fish.
0:20:10 > 0:20:14And, as salmon migrate into the bay, the whales are in for a treat.
0:20:17 > 0:20:22The orcas know just how to catch them and stealth is not required.
0:20:23 > 0:20:25They rely on shock and awe.
0:20:27 > 0:20:29They make as much noise as possible,
0:20:29 > 0:20:32slapping the water with their 2m-wide tails.
0:20:39 > 0:20:42The shock waves stun or disorientate the fish.
0:20:44 > 0:20:46And breaching adds to the confusion.
0:20:51 > 0:20:54They then charge into the shoal, knocking the fish for six.
0:21:03 > 0:21:05Each orca must catch 50 salmon a day
0:21:05 > 0:21:09and their group skills make sure that none go hungry.
0:21:16 > 0:21:19Another pod nearby favours completely different food.
0:21:24 > 0:21:27They specialise in catching dolphins and seals.
0:21:32 > 0:21:34They've acquired a different set of skills
0:21:34 > 0:21:37geared to outsmarting their quick-thinking prey.
0:21:46 > 0:21:49They spot their food by spy-hopping.
0:21:55 > 0:21:57A wake may be the only sign.
0:21:59 > 0:22:00They check again.
0:22:06 > 0:22:09It's just what they've been looking for.
0:22:15 > 0:22:19Dall's porpoises - the fastest dolphins in the ocean.
0:22:19 > 0:22:22They reach speeds of over 35mph.
0:22:30 > 0:22:32Orcas nearly match them for speed
0:22:32 > 0:22:34but the porpoises are much more manoeuvrable.
0:22:40 > 0:22:44As the orcas dive, they switch to stealth mode.
0:22:46 > 0:22:49And try to sneak up undetected.
0:22:51 > 0:22:54But the porpoises just keep on accelerating.
0:23:04 > 0:23:06The orcas' endurance is tested to the limit.
0:23:12 > 0:23:14And the porpoises race to freedom.
0:23:18 > 0:23:20The orcas look for far easier prey.
0:23:22 > 0:23:25A lone sea lion is an unsuspecting target.
0:23:54 > 0:23:57Despite living close to one another,
0:23:57 > 0:24:01the pods that hunt mammals never interact with those that catch fish.
0:24:03 > 0:24:05They not only pursue different prey,
0:24:05 > 0:24:08they even have different calls and dialects.
0:24:20 > 0:24:21Back in Mozambique,
0:24:21 > 0:24:24another spy creature joins the surveillance team.
0:24:24 > 0:24:31This is Spy Puffer, a pufferfish with a camera in his mouth.
0:24:33 > 0:24:35He immediately starts filming the young male
0:24:35 > 0:24:37and his humpback friend.
0:24:44 > 0:24:46They seem to be getting along just fine.
0:24:52 > 0:24:56A second pufferfish joins - this one has cameras for eyes.
0:24:59 > 0:25:00They make a great double act.
0:25:00 > 0:25:03One films forwards, the other sideways.
0:25:14 > 0:25:16They immediately prove popular.
0:25:25 > 0:25:29Close by, Spy Baby has found yet more dolphins.
0:25:30 > 0:25:34It's gang of young males that have also just left their mothers.
0:25:40 > 0:25:43They seem totally unfazed by their first meeting with Spy Baby.
0:25:54 > 0:25:56These young males hang out together,
0:25:56 > 0:25:59both for company and to share knowledge.
0:25:59 > 0:26:02The young bottlenose may have made a friend
0:26:02 > 0:26:04but it's the wisdom of the crowd he needs.
0:26:06 > 0:26:10He cautiously approaches the gang with the humpback by his side.
0:26:15 > 0:26:16He whistles out with his name
0:26:16 > 0:26:19but there's no guarantee he'll be accepted.
0:26:19 > 0:26:21Especially with his strange friend in tow.
0:26:25 > 0:26:29The humpback stays close as the bottlenose tries to join the pod.
0:26:32 > 0:26:35He's seeking reassurance from his friend.
0:26:44 > 0:26:47A pod doesn't accept newcomers willingly,
0:26:47 > 0:26:49even those of the same species.
0:26:50 > 0:26:53A dolphin starts to drive the humpback away.
0:26:58 > 0:27:02And anyway, humpbacks tend to prefer their own company.
0:27:05 > 0:27:07As he turns to leave,
0:27:07 > 0:27:10his bottlenose friend must decide whether to stay or join him.
0:27:15 > 0:27:19But to the bottlenose it's clear where his choice should be.
0:27:19 > 0:27:22As the humpback returns to a solitary life,
0:27:22 > 0:27:25his friend chances his luck with the motley crew.
0:27:30 > 0:27:32The pod has a strong hierarchy
0:27:32 > 0:27:36but he has an unusual method to wheedle his way in.
0:27:45 > 0:27:47He begins to act like a female,
0:27:47 > 0:27:50deploying feminine charm to win them over.
0:27:59 > 0:28:01It seems to be working.
0:28:12 > 0:28:15They even perform mating rituals.
0:28:34 > 0:28:38By discovering his feminine side he's gradually accepted.
0:28:41 > 0:28:43Every male undergoes this initiation rite
0:28:43 > 0:28:46before he is allowed to join the gang.
0:28:50 > 0:28:52This is his new family now
0:28:52 > 0:28:56and he'll soon be party to everything they know.
0:28:59 > 0:29:03Such strange rites of passage have never been filmed before
0:29:03 > 0:29:07and have previously been mistaken for males attacking females.
0:29:08 > 0:29:10In other parts of the world,
0:29:10 > 0:29:13more strange rituals are still being discovered.
0:29:16 > 0:29:18Recently, in Shark Bay, Western Australia,
0:29:18 > 0:29:22some bottlenose dolphins have taken to wearing what look like hats.
0:29:27 > 0:29:31They're actually sea sponges, which they balance on their noses.
0:29:36 > 0:29:39This is the first time this behaviour has been filmed
0:29:39 > 0:29:42but the reason they carry them remains a mystery.
0:29:49 > 0:29:51One thought is that they use them
0:29:51 > 0:29:54to protect their noses as they root around in the sand.
0:30:01 > 0:30:04But some look a bit big for the job.
0:30:15 > 0:30:18As they live in such cloudy water,
0:30:18 > 0:30:20the real reason has yet to be confirmed.
0:30:30 > 0:30:34Sometimes, mysteries just add to an animal's intrigue.
0:30:38 > 0:30:39Just a few miles away,
0:30:39 > 0:30:43the unique behaviour of another bottlenose pod is better understood.
0:30:48 > 0:30:52Each day, they enter this shallow bay.
0:30:57 > 0:31:02They seek the fish that gather around the shoreline.
0:31:02 > 0:31:06As the fish dart away, they instinctively head to the shore,
0:31:06 > 0:31:08where it's too shallow for dolphins.
0:31:11 > 0:31:14But this is all part of the dolphins' strategy.
0:31:19 > 0:31:22Fish that make a break for it are chased right back.
0:31:31 > 0:31:34As usual, the young are watching and learning.
0:31:42 > 0:31:44The fish soon fringe the shallows,
0:31:44 > 0:31:47but they've been lulled into a false sense of security.
0:31:54 > 0:31:57The dolphin now steps on the accelerator,
0:31:57 > 0:32:00powering into the dangerously shallow water.
0:32:05 > 0:32:09The sudden turn of speed raises her back clean out of the water.
0:32:13 > 0:32:17A few thrusts from the tail and she hydroplanes across the surface,
0:32:17 > 0:32:20covering ten metres in less than a second.
0:32:25 > 0:32:29Using this technique, she easily outpaces the surprised fish
0:32:29 > 0:32:32and also avoids becoming stranded.
0:32:42 > 0:32:45It's a skill known only by the dolphins of Shark Bay.
0:33:39 > 0:33:42In South Carolina, some bottlenose pods
0:33:42 > 0:33:46have found a far easier way to get a meal
0:33:46 > 0:33:49they simply learn the routines of the local shrimping boats.
0:33:54 > 0:33:57When their nets are ready to be hauled,
0:33:57 > 0:34:00the dolphins rush out to join them...
0:34:00 > 0:34:04and grab any dead or injured fish that fall through.
0:34:07 > 0:34:10But sometimes even that much effort's not required.
0:34:13 > 0:34:16The unwanted catch is thrown back into the sea
0:34:16 > 0:34:19and into the mouths of the waiting dolphins.
0:34:24 > 0:34:27It's the ultimate breakfast buffet.
0:34:39 > 0:34:42Dolphins may be incredibly inventive,
0:34:42 > 0:34:45but they are also clever enough to grab a takeaway when they can.
0:34:45 > 0:34:50They are ever adaptable, constantly watching and learning new skills.
0:34:53 > 0:34:56In Mozambique, the young bottlenose has been in the gang for
0:34:56 > 0:35:00many weeks and, from them, has picked up
0:35:00 > 0:35:03many new talents along the way.
0:35:03 > 0:35:07He's also found a new friend.
0:35:07 > 0:35:11Most males have a best mate within a pod.
0:35:11 > 0:35:16Once formed, this bromance can last a lifetime.
0:35:25 > 0:35:28As ever, spy creatures watch their every move.
0:35:33 > 0:35:37The mock turtle is already proving a hit.
0:35:37 > 0:35:39And so are the puffers.
0:35:44 > 0:35:49The young male gives his new-found friend a guided tour.
0:36:02 > 0:36:04The pair are becoming inseparable.
0:36:11 > 0:36:15The reef is a rich stomping ground for these teenage tearaways.
0:36:22 > 0:36:25The young male learnt most of his skills from his mother,
0:36:25 > 0:36:29but he's making a whole new set of discoveries with his latest pals.
0:36:37 > 0:36:40A real puffer fish offers the chance for bored teenagers
0:36:40 > 0:36:42to have some fun.
0:36:56 > 0:37:00He tries to hide, but he won't get off that lightly.
0:37:00 > 0:37:03His next defence is to inflate like a ball.
0:37:06 > 0:37:08Now the game can really begin...
0:37:19 > 0:37:21Playing catch is a great pastime.
0:37:26 > 0:37:30They take turns to carry and pass it between each other.
0:37:41 > 0:37:45But something far more extraordinary seems to be happening.
0:37:47 > 0:37:52When attacked, puffer fish release a neurotoxin.
0:37:52 > 0:37:54In high doses it can kill,
0:37:54 > 0:37:58but, in small doses, it has a narcotic effect.
0:38:04 > 0:38:07It seems to be affecting the dolphins.
0:38:17 > 0:38:21They appear totally blissed out by the whole experience.
0:38:31 > 0:38:35And remarkably, all take turns in passing the puffer around.
0:38:41 > 0:38:45This is the first time that apparent recreational drug use
0:38:45 > 0:38:47has been documented in dolphins.
0:38:59 > 0:39:03With the dolphins otherwise engaged the puffer deflates.
0:39:03 > 0:39:06He's free to go on his way.
0:39:07 > 0:39:11It looks like they will be distracted for quite some time.
0:39:23 > 0:39:26Back in the Caribbean, the camera dolphin shows
0:39:26 > 0:39:29just how much he interacts with other dolphins.
0:39:33 > 0:39:38If another dolphin calls, he immediately answers.
0:39:38 > 0:39:40LOW WHISTLE
0:39:47 > 0:39:50He uses dozens of different calls, telling all the dolphins in
0:39:50 > 0:39:54the local area where he is and what he's doing.
0:39:54 > 0:39:56LOW WHISTLE
0:39:56 > 0:39:59The lips of the blowhole act like a mouth,
0:39:59 > 0:40:00adjusting the sound.
0:40:03 > 0:40:05CLICKING
0:40:09 > 0:40:11Before long, his calls are answered.
0:40:18 > 0:40:22In murky water, it's the only way they can stay in contact.
0:40:29 > 0:40:32Different pods have different dialects or accents,
0:40:32 > 0:40:35and each sound has a specific meaning.
0:40:39 > 0:40:42WHISTLING
0:40:51 > 0:40:55They hear a far greater range of frequencies than we can,
0:40:55 > 0:40:58so we can only eavesdrop on a fraction of their conversations.
0:41:13 > 0:41:15WHISTLE
0:41:19 > 0:41:23Blasts of bubbles add emphasis to what he's saying.
0:41:30 > 0:41:34And special calls are reserved for the opposite sex.
0:41:34 > 0:41:37Some of their sounds are quite bizarre.
0:41:39 > 0:41:42LOW LOUD BLOWING SOUND
0:41:42 > 0:41:46This is actually a love song and it seems to be working.
0:41:50 > 0:41:52The females allow him to approach...
0:41:54 > 0:41:55..but not for long.
0:41:57 > 0:41:59CLICKING
0:41:59 > 0:42:01LOW LOUD BLOWING SOUND
0:42:06 > 0:42:10He catches up and, this time, the females wait for him.
0:42:18 > 0:42:20He checks her out...
0:42:23 > 0:42:26..but she's still nursing, so of no interest at all.
0:42:35 > 0:42:37LOW GUTTERY SOUND
0:42:37 > 0:42:39He takes a deep breath.
0:42:41 > 0:42:45Time for a well-earned rest after all his efforts.
0:42:51 > 0:42:54He starts to go to sleep.
0:42:58 > 0:43:02And the fish play dare around their snoozing predator.
0:43:06 > 0:43:09Dolphins have a bizarre way of sleeping.
0:43:09 > 0:43:12Each half of their brain rests in turn,
0:43:12 > 0:43:16allowing the other half to stay awake and alert to danger.
0:43:24 > 0:43:28In Mozambique, the male pod is still very much awake.
0:43:30 > 0:43:34And Spy Squid is on filming duty.
0:43:34 > 0:43:36He's found a hawksbill turtle...
0:43:44 > 0:43:46Squid takes a closer look...
0:44:01 > 0:44:03..but he needs to be careful.
0:44:08 > 0:44:12A potato cod has him in his sights.
0:44:20 > 0:44:24Squid beats a retreat...
0:44:24 > 0:44:25and then goes back to work.
0:44:29 > 0:44:31It's not a moment too soon -
0:44:31 > 0:44:34the pod is chattering with excitement.
0:44:39 > 0:44:41The two friends stick close together
0:44:41 > 0:44:44as the reason for their concern becomes clear.
0:44:49 > 0:44:52Another gang of males is approaching.
0:44:56 > 0:44:58The home pod takes up defensive positions
0:44:58 > 0:45:03as the two groups square up for a territorial fight.
0:45:03 > 0:45:06Then it all kicks off.
0:45:27 > 0:45:31When two pods come together, the existing hierarchy can break down.
0:45:37 > 0:45:40It's how new groups and alliances are formed.
0:46:08 > 0:46:12The pair decide that, for now, they're safer on their own.
0:46:16 > 0:46:18They leave the rest to fight it out.
0:46:21 > 0:46:24They may rejoin the pod when things calm down.
0:46:30 > 0:46:33Bottlenose can choose when to be social or alone,
0:46:33 > 0:46:36but some dolphins don't have this option.
0:46:36 > 0:46:39It's late summer in Patagonia
0:46:39 > 0:46:42and the beaches are packed with breeding sea lions.
0:46:47 > 0:46:50And, as their young are about to enter the water,
0:46:50 > 0:46:52an orca pod arrives like clockwork.
0:46:56 > 0:47:00They are a family that has hunted here for generations,
0:47:00 > 0:47:03and they have devised a spectacular way to get a meal.
0:47:10 > 0:47:13The adult sea lions are wise to their plan
0:47:13 > 0:47:15and usually see them coming.
0:47:36 > 0:47:39But the new pups aren't so smart.
0:47:43 > 0:47:46The orcas patrol the surf zone
0:47:46 > 0:47:48waiting for one of them to make a mistake.
0:47:53 > 0:47:56Sooner or later, they have to enter the water.
0:47:56 > 0:48:00And this is when the orcas strike.
0:48:02 > 0:48:05A near miss, but she'll have plenty of other chances.
0:48:13 > 0:48:16But when it comes to catching sea lion pups,
0:48:16 > 0:48:19there is one orca better than all the rest.
0:48:44 > 0:48:46The expert is a 50-year-old male,
0:48:46 > 0:48:50who's hunted these waters all his life.
0:48:52 > 0:48:54The technique is a family tradition
0:48:54 > 0:48:56and training starts at an early age.
0:49:07 > 0:49:10They have been hunting sea lions like this for generations.
0:49:24 > 0:49:27Each orca uses their own subtle variations,
0:49:27 > 0:49:30but none is as accomplished as the old male.
0:49:36 > 0:49:39This should be suicidal for a ten-tonne Orca -
0:49:39 > 0:49:43around the world hundreds die from stranding each year.
0:49:47 > 0:49:49Even he seems to be struggling...
0:49:52 > 0:49:54..but he has survived for half a century.
0:49:54 > 0:49:56He clearly knows what he's doing.
0:50:00 > 0:50:02He's never left high and dry.
0:50:10 > 0:50:12Even in a pod where skills are shared,
0:50:12 > 0:50:16there is always one individual who outshines the rest.
0:50:46 > 0:50:48Despite the value of working in a pod,
0:50:48 > 0:50:51in Mozambique, the two dolphin friends discover
0:50:51 > 0:50:54there can be advantages to being independent.
0:50:57 > 0:50:59They meet a group of females
0:50:59 > 0:51:02and are already faring better for being on their own.
0:51:05 > 0:51:08A female has even started to show some interest,
0:51:08 > 0:51:10flirting with the young male.
0:51:20 > 0:51:23Things are going well, but the pair won't be alone.
0:51:28 > 0:51:31His best friend plays gooseberry in this new romance.
0:51:45 > 0:51:50Not put off, the female shows her interest by some seductive moves.
0:51:55 > 0:51:58She also blushes pink a total giveaway!
0:52:02 > 0:52:05And there's nothing subtle about her fin slaps.
0:52:12 > 0:52:15Yet, all the time, the courting pair
0:52:15 > 0:52:18are accompanied by the young male's friend.
0:52:18 > 0:52:20But this best mate has a job to do -
0:52:20 > 0:52:24watching his friend's back while he's otherwise engaged.
0:52:24 > 0:52:27He chases off other males that might muscle in.
0:52:32 > 0:52:36In dolphin world, it's what best friends are for.
0:52:41 > 0:52:44And to guarantee success, the courting male gathers
0:52:44 > 0:52:47a bouquet of seaweed for the new love of his life.
0:53:51 > 0:53:54As the happy couple play with the garland,
0:53:54 > 0:53:56their relationship is complete.
0:54:07 > 0:54:10It seems that the friend isn't doing too badly either -
0:54:10 > 0:54:12he's found himself a girlfriend too.
0:54:16 > 0:54:19It's a match made in underwater heaven.
0:54:44 > 0:54:46Back in the Caribbean,
0:54:46 > 0:54:49the camera dolphin is doing what dolphins love the most
0:54:49 > 0:54:51racing through the waves.
0:55:00 > 0:55:01Like all the dolphins we've seen,
0:55:01 > 0:55:06he has taken us on an incredible journey into his secret world.
0:55:11 > 0:55:14He then treats us to something extraordinary
0:55:14 > 0:55:17he barrel rolls with joy.
0:55:18 > 0:55:24Then, for the first time, the view from his back as he leaps.
0:55:38 > 0:55:42Dolphins are the cleverest creatures in the ocean.
0:55:45 > 0:55:49And, as they have shown us, they certainly have the most fun.
0:57:11 > 0:57:16Out on the reef, Spy Squid goes on one last adventure.
0:57:16 > 0:57:20He soon meets his archenemy the potato cod.
0:57:23 > 0:57:24Another joins...
0:57:29 > 0:57:31And yet another...
0:57:31 > 0:57:33This doesn't look good.
0:57:36 > 0:57:40He valiantly keeps filming, but he's completely surrounded.
0:57:58 > 0:58:01And then...catastrophe.
0:58:19 > 0:58:23Among the fishes, he rests in pieces,
0:58:23 > 0:58:26but like all the spy creatures,
0:58:26 > 0:58:28his job is done.