"This is a blue whale, the largest animal on the planet." "In fact, the largest animal that has ever lived." "It's 100 foot long and weighs nearly 200 tonnes." "For millions of years, these giant whales and their super-intelligent cousins, the dolphins, have ruled the world beneath the waves." "Sadly, our relationship with them has not always been a friendly one." "In the past, we persecuted them." "But today we are reaching out to them and experiencing a sense of wonder that's hard to explain." "As we explore the seven seas, we'll come face to face with the world's most extraordinary whales and dolphins." "Uncovering their secrets alongside the scientists who dedicate their lives to understanding them." "The great mystery is, what are the whales doing here?" "These killer whales demand respect." "They've taken out a minke whale that probably weighs more than ten tonnes." "I think we could talk to dolphins within five years." "Sharing these breathtaking encounters, two of the world's top underwater cameramen." "I've waited a long time to see a blue underwater, and that was just magic." "Fantastic, today is the best day of my life." "Whales are born to be big." "Even this newborn baby weighs over a tonne." "So what is it like to live your life as an ocean giant?" "Part of our attraction to whales has always been their gentle nature." "But we are beginning to discover a different story, one spiced with sex and violence." "Every spring thousands of humpback whales are drawn to Hawaii, the world's most remote island chain, to do battle." "A scientific team heads out over the tropical seas of Maui," "for a bird's-eye view of one of nature's greatest showdowns." "Gangs of humpback whales posture, ram, and can even kill each other." "So what has driven these giants to fight?" "The answer to this question needs a close-up view of the action from underwater." "Jeff Kalbach has spent 15 years watching fighting whales, trying to make sense of their belligerent behaviour." "OK, she is ready to go." "He's joined by ex-Cousteau cameraman Didier Noirot, who's hoping to find more clues by going right into the thick of the action." "Humpbacks are my favourite whales." "I have filmed them many times before but there is one thing I'm really keen to see, is to see the fight of the males." "It's going to be very dangerous, you can be hit by the tail end." "I guess you can die." "They go so fast underwater despite their size, and that's going to be, like, a challenge for me." "There's news of some action a mile offshore." "See that pectoral fin, the white?" "Now it's going up, rolling over." "A female humpback announces she's here, and she's ready to mate." "These fin slaps can be heard a mile away." "And almost immediately a gang of suitors is headed her way." "One, two, three, four, five, there's definitely six, seven." "Oh, big guy." "Before long, she's surrounded by male admirers." "To help her choose the strongest mate she sets the ultimate fitness contest." "She sets off on a marathon swim with the pack of jostling males in hot pursuit." "Each one is trying to win her affections by staying as close to her as possible." "All ready to go?" "Yes, exactly." "We have to go." "Underwater, the 40-tonne males might seem relaxed but the tension is building." "They are already sizing each other up." "These lustful rivals could do battle at any minute." "Didier must stay alert." "He can't risk diving with scuba tanks, as any dispelled air could be interpreted as a challenge by the males, who blow bubbles as a sign of aggression." "Like now." "Suddenly, the female comes into view, escorted by a bubble-blowing lead male, or "primary"." "It's a good start to the filming." "There was the two animals right here and I could tell that wasn't the female or the primary so we were looking and then all of a sudden, Didier was like, ooh, he hits me and then right behind us was the primary" "coming with a bubble trail." "Bubble trail which I filmed." "Yes." "Jeff believes the escort uses bubbles to produce a 100-foot curtain to screen the female from other challengers." "And, with lungs the size of a car, it's the biggest male that can expel the most air." "This hot pursuit can last all day and cover miles of ocean." "To stand a chance of catching the action the team must race ahead." "Meanwhile, the competition escalates to explosive shows of strength." "Look at that, he's riding contact with her, you can see his pec fin." "The other animals are colliding into him, look at him pushing and shoving." "See that fluke just flick over like this and he's diving down, charging at somebody, pushing somebody away." "For the dive team, it's like jumping into six lanes of traffic." "Testosterone-fuelled giants charge by at 20 miles per hour." "A male upends into the crucifix block, a tactic to stop a rival in its tracks." "As the violence intensifies, it becomes more dangerous for the rival whales and for the cameraman." "A huge male charges straight for his bubble-blowing rival, ramming him off course." "For Didier, it is the dive of a lifetime." "It was amazing." "It was perfect, good dropping, thank you, good advice, we are just at the right time at the right moment." "We saw the collision and then that male...with his, all his bubbles." "Using his weight advantage, the bigger male takes the lead, but the female has yet to choose her mate and the marathon continues." "Let's go." "Let's go." "Go, go." "Then, suddenly, the mood changes." "The female has vanished, perhaps having eloped with her chosen male." "And without the object of their desire the heat has gone out of the battle." "Minutes after duelling in the high seas, the males are caressing each other in a graceful ballet." "And they stopped, they danced like a ballet, beautiful." "How beautiful to watch them just moving and turning and touching." "It was spectacular, very spectacular." "Despite the scientists' best efforts, no-one has ever seen humpbacks mating." "But everything points to the female choosing the biggest blowing and hardest hitting male to be the father of her young." "It's not just humpback males for whom size really matters." "Here, off the coast of Argentina, is the biggest whale orgy on the planet." "In the sheltered bays of Peninsula Valdes, 7,000 southern right whales come to mate, give birth and raise their young." "Even for a veteran cameraman, it's an extraordinary spectacle." "I have never seen that before." "So many whales, so close to shore." "It's probably the only place in the world you can see that." "Right whales are huge, at least twice the sizes of humpbacks." "Their tails alone match the wing span of a light aircraft." "Unlike the aggressive humpbacks, male right whales are surprisingly gentle lovers." "A 40-year project studying the lives of these extraordinary creatures offers a unique opportunity to get close to these gentle giants, and Didier can't wait." "I love southern right whales, they are probably the friendliest of the whales, they are very approachable, they don't mind the divers, and here in Patagonia the water is very clear so I'm really looking to do something fantastic." "Exploring the mating habits of these friendly whales is Dr Mariano Sironi." "Tragically, it's their very friendliness that made them such easy targets for the early whalers and made them the "right" whales to hunt." "Today, these giants are making a slow but promising recovery, thanks to conservationists like Mariano, and to their..." "..amorous nature." "You see the male in the right position under the female?" "Yeah." "You can see the flipper of the male hugging the female, and they are belly to belly." "Both sexes are very promiscuous, and the males are equipped with a particularly astonishing adaptation for mating, a pair of giant testicles!" "Their two testicles together can weigh up to one tonne." "The testes of the right whale are 20 times heavier than those of the blue whale..." "20?" "!" "..so, that's an indication of a very sexual species." "Mariano is investigating the link between the size of a male's giant testicles and his chances of paternity." "But making sense of this mass of writhing bodies at the surface is difficult." "To complete the picture, Didier must get in the water." "Let's go." "With most whales, getting close to them is the challenge." "WHALE GRUNTS" "WHALE BELLOWS SLOWLY" "They are so friendly that a diver must be careful not to be accidentally crushed by one of these 80-tonne giants." "Underwater, it becomes abundantly clear that males not only boast giant testicles but that, at nine foot long, they have the biggest penis in the animal kingdom." "And one which appears to have a mind of its own!" "When they finally mate, it's belly to belly." "But this is just the start for the female, as she goes on to mate with the rest of the males, sometimes up to five or six at a time." "After an hour of being spellbound by this extraordinary courtship," "Didier's air finally runs out." "That was just fantastic." "Good." "What I have seen just now is the most amazing spectacle" "I have ever seen underwater." "Ohh, that's good." "Didier's intimate images of the mating will be invaluable to Mariano's study." "By mating with a variety of males, the female ensures that the battle for paternity goes on inside her and not in the open seas." "But it's still the biggest male that stands the best chance of winning that battle, because by having the longest penis and largest testicles he can flush out any competitor's sperm." "For male southern right whales, size really does matter." "And in 12 months' time this female will give birth to a calf that will inherit its father's strength and, most importantly, his size." "But here, off the west coast of Mexico, it's the size of the mother that matters." "These calm, safe waters are ideal nurseries for these playful grey whale newborns." "For the first three months of their lives, when they're at their most vulnerable, the calves live in peace, feeding only on their mothers' milk." "The calf has tripled in weight, but for his mother there's nothing to eat here." "For her own survival, she must leave this safe haven and lead her calf on a perilous journey, the longest made by any mammal." "From the barren waters of Mexico, they will swim 6,000 miles to the rich feeding grounds of Alaska." "During its 50-year lifespan, a grey whale will swim over half a million miles!" "As they head north from Mexico, they hug the coastline, hiding in the murky shallows." "But at Monterey Bay, California, they can take a short cut across the deep mouth of the bay, and that's a gamble." "They're now exposed to attack." "At dawn, a scientific research team heads out into the troubled waters of the bay." "BELL RINGS, SEALS BARK" "John Durban is studying the attacks on grey whales." "This is one of the most important ambush points for grey whales along the coast." "The grey whales are coming to this point here and making the decision whether to tuck round in the bay or cut across to the other side and save them some time." "But what could possibly take on a 30-tonne whale, especially one defending her calf?" "No-one knows better than underwater cameraman Doug Allan." "Ten years ago, he filmed a ferocious attack in this exact spot." "And what he saw was the oceans' top predator in action." "Killer whales." "The intensity of the battle has left a lasting impression." "It's a very harrowing experience watching killer whales take down a grey whale calf." "The calf tries so hard to survive, the mother does all she can, too." "The killer whales are just so relentless, they harry, harry, and they will just take those two apart." "A male killer whale is ten tonnes of pure power, a cunning mind and 60 teeth." "The killers targeted the defenceless calf, its survival dependent on the strength and size of its mother." "The killer whales' strength is in numbers." "They launched coordinated attacks to outmanoeuvre the mother." "But she wasn't going to give up her only calf without a desperate fight." "Four times the size of her attackers and with thick skin protected by barnacles, she beat them back with deadly tail swipes." "But the killer whales had chosen their victim well." "The mother was neither big enough nor strong enough to withstand the onslaught, and the killers drove a wedge between mother and calf." "Eventually, they drowned the isolated calf." "After six hours, the battle was over, the mother exhausted, the calf killed and eaten." "A decade on," "John is waiting for this season's killer whale attacks to begin." "What's happening, John?" "They got killer whales, they're about a mile north of the ship over here, the Miller Freeman, and the killer whales were chasing something when they arrived, they've stopped." "John is planning to attach state-of-the-art satellite tags to these killer whales for the first time." "We've got a group of killer whales." "As we're coming up we can see there are birds overhead, and you can smell a really strong fishy smell right now." "That's a good indication they've killed recently, that's the blubber smell of a whale." "The attack is over but the killer whales are now feeding on their victim." "The bulk of the carcass is probably sinking and they're trying to hold it up, but we have seen a whale with a big chunk of flesh in its mouth." "They're probably dismantling it right now." "These killer whales just demand respect." "The feasting whales offer John the best chance to secure a tag." "Right under us here, it's going forwards, so if you go forward a little..." "To work properly, the tag must be positioned perfectly on the dorsal fin." "John's aim has to be spot on." "I'm waiting..." "OK, this one's coming up here." "Perfect." "Oh, yeah, look at that, it's flush." "Just the tapes..." "the antenna looks good." "With so many killer whales gathered in one place," "John is eager to secure as many tags as he can." "That's good, right there, it's good." "When you tagged those whales they didn't flinch." "That's the nice thing about small tags, it's an issue of scale." "We're putting a 40-gram tag on a seven-tonne whale." "They don't notice it." "Now we've got some tags on, the signals are going to get pinged from the tags up to some satellites and we receive the signals on my phone." "That'll allow us to track them over the next few weeks, hopefully." "John can now track their movements and, critically, work out how often grey whales are attacked." "Only one week later, some extraordinary results come through." "Rather than wait in ambush in the bay, these killer whales have headed way up the coast." "Here's Monterey Bay, to give an idea of the scale." "It looks pretty small on this chart." "The first group we tagged, in eight days now, no, further, have moved all the way to the top of this chart to Northern Oregon by the Umpqua River." "It's over 700 kilometres." "The hungry killer whales have had to broaden their search for prey way beyond Monterey Bay," "perhaps because there are far fewer grey whale mother and calves undertaking their epic migration this year." "It's highly likely that this immense migration, probably the longest regular migration of any mammal, is largely due to the threat of predation by killer whales." "Grey whales may choose to breed in Mexico, thousands of miles away from their northern feeding grounds, simply to keep the calves safe from killer whales for as long as possible." "After three months travelling, the grey whales finally make it to Alaska." "The emaciated whales can now gorge themselves." "Each day they sieve out over a tonne of shellfish from the muddy seabed." "But it's only the largest, strongest and most determined mothers who can save the lives of their calves on this most gruelling of migrations." "Further north, within the Arctic Circle, lives a whale three times the size of a grey whale." "And it's grown massive for even more extraordinary reasons." "As it stays in the Arctic all year round, it doesn't need to be big to survive lengthy migrations." "And, protected by the maze of shifting pack ice, it has less to fear from killer whales." "It's a bowhead whale, named after its enormous curved upper jaw." "So, why is this whale so big?" "In eastern Greenland, a scientific team is attempting to unlock the secrets of this little-known giant." "Cameraman Doug Allan has 30 years' experience filming at the frozen poles." "Every time I come to the Arctic" "I think, "This is it, never again." "Next shoot, Caribbean,"" "but there is something special about this that keeps pulling you back." "In the last two centuries, bowheads were almost wiped out by commercial whalers, and are notoriously wary of humans." "No-one knows this better than Doug." "I think if bowheads had personalities they'd be a little bit sad." "They've had such a lot of bad things done to them, were almost wiped out, but somehow I think they're coming back." "They'd like to be friendlier but they just don't yet know how to trust us." "WHALESONG ECHOES" "During the winter bowheads are impossible to track, but in spring they announce their presence with song." "Eavesdropping on these mysterious giants is scientist Outi Tervo." "She's one of the very few whale researchers prepared to tough it out in this brutally hostile part of the world." "It's a "Whooo"... ..and then a "Rughhhh."" "Outi suspects that these are mating calls and that the bowheads may be gathering somewhere close to breed." "Can I have a listen?" "Yeah, sure." "Ah, "Whooo!"" ""Oooh," says the other one." ""Oooh, I like you."" "Outi has never been able to see bowheads under the ice before and hopes that Doug's camera might offer new insights into the world of these secretive whales." "Unfortunately for Doug, bowheads are the masters of concealment, able to hold their breath for up to an hour and a half." "To make matters worse, the elements aren't exactly inviting." "Brrrrrr!" "It's minus 20 degrees Celsius and Doug hasn't even got in the water yet." "But at least there's a whale!" "She just heard me coming, I think." "Bowheads are remarkably alert to danger." "One small splash and this one simply melted away." "The only hope is for a whale that is a little less skittish." "Gosh, these whales..." "Gee, they're hard to get close to." "As the game of cat and mouse continues, the Arctic weather closes in." "Even with his insulated dive suit" "Doug is close to hypothermia after just two hours." "LAUGHING:" "I must be mad." "But how do bowheads survive this cold?" "It's all to do with being a giant." "The bigger and rounder the body, the better it is at retaining heat." "Wrapped in 50 tonnes of insulating blubber, these whales are the fattest animals on the planet." "Indeed, half their entire body weight is fat!" "The team continues to try to film the bowheads underwater, this time using a pole camera." "For the whale, this method of filming may be less intrusive, and for Doug, well, it's just a little bit warmer." "Hold it there, I can see a fluke." "That was the first underwater shot of the bowhead." "I'm sure we can improve on it, but at least it's a start." "Already they're discovering something distinctive about these creatures." "The footage reveals a patchwork of markings all over the whale's body." "Bowheads use their backs to break through the ice to create vital breathing holes, permanently scarring their skin in the process." "These patterns are as unique as fingerprints and help identify each individual whale." "Nice shot, nice shot." "With the whales so close, it's an ideal opportunity for the scientists to collect a DNA sample." "No more than a pin prick to these fat-coated giants." "Analysis of bowhead tissue samples is revealing some extraordinary links between their size and their age." "Some estimate they are over 200 years old, so this could be a sample of a 200-year-old whale." "But that would make that animal one of the oldest living animals on the planet." "Yes, it would be the oldest mammal we know of right now." "WHALESONG" "Bowheads can live for over 200 years because they have a lower body temperature than any other whale, and the lower your body temperature, the slower you age." "These enormous whales can afford to live life slowly, roaming the rich Arctic waters, simply opening their mouths and filtering all the food they need." "Uniquely, a bowhead's backbone never fuses, so all that time they never stop growing." "Just think of all the wisdom that's in that whale." "For 200 years he's swum around the Arctic, slowly finding his way around." "They are amazing, and still mysterious too." "Although this gentle giant can grow for centuries, there is one whale that is even bigger." "Only in the vastness of the ocean could there live the largest creature on earth." "The blue whale." "Before commercial whaling, 300,000 blue whales cruised the oceans." "Today, less than 10,000 remain." "We know almost nothing of their lives and for years assumed that, like the other great whales, they migrated to cold, rich seas to feed." "Yet, in the warm tropical waters off Sri Lanka in the Indian Ocean, blue whales seem to be living here all year round." "An international team of scientists, led by Anouk Ilangakoon, has pioneered blue-whale research here through the decades of civil war." "This is a once-in-a-lifetime opportunity for cameramen Doug and Didier, who have never managed to film blue whales before." "They're not easy to approach like southern right whales." "They're not friendly like humpback whales." "These are very difficult characters." "If I get one shot of a blue whale underwater, that would be a dream come true." "They head out into blue-whale territory, 20 miles into the open ocean." "Despite Anouk's decades studying blue whales, she is still unsure how many there are off Sri Lanka, and why." "Sri Lankan blue whales seem to be pretty unique." "They seem to stay around here year round and the real mystery is what are they feeding on?" "And what is there to sustain them throughout the year in these waters?" "Will it finally be possible to record what these mysterious whales are up to?" "The whales remain elusive." "Did you get me my shot yet?" "That was the first time!" "No, be patient." "This is going to be difficult, you know." "Those whales were..." "They didn't stop, they just came towards me." "Perfectly streamlined, blues are one of the fastest ocean giants, powering along at over 30 miles an hour." "But at least they're sticking around." "So what holds them to this patch of blue sea off Sri Lanka?" "By measuring how temperature and salinity change with depth, scientist Asha de Vos believes she has the answer." "What I've discovered is that along our coastline there are these areas of upwelling, pretty large areas, which are bringing all this cold, nutrient-rich water from the depths to the surface, which might be providing conditions for whale food." "The upwelling of cold, nutrient-rich water is unusual for the tropics, but appears to contain the perfect food for blue whales, whatever that is." "Any images of whales feeding in Sri Lanka will not only be a first, but will also help support Asha's theory." "Ironically, the water is so full of nutrients, it's too murky to film in." "I could see that guy almost coming in." "He put his head down." "But, of course, with an 80-foot whale, when the head goes down, it's 80 feet down, and I just lost the head." "Lovely view of the tail going through." "Big, big tail." "I swum very fast toward the whale, but then, all of a sudden," "I saw all the massive animal coming to me so quickly..." "What an experience." "I was lucky not to be hit, but I really want to see it again." "So far, the footage suggests that, if the whales are feeding, it must be at depth." "Ari Friedlaender, another member of the research team, is investigating the duration and depth of each whale's dive." "OK, I think that's the animal from that third group, so that dive time is about seven minutes." "I'd probably say, just based on that dive time, maybe between about 50 and 200 metres." "I think it's pretty clear that these guys are feeding." "They're lunging quite a bit down there too." "Ari is now convinced the whales are feeding at great depth, but on what?" "The whales leave behind crucial evidence floating on the surface." "This is whale poo." "Whale poo?" "!" "That's right." "It's red in colour, and that gives us a clue to what it is, actually." "It's full of krill." "That's what they feed on?" "That's right." "The largest creature in the ocean feeds almost exclusively on one of the smallest... krill." "A crustacean just a few inches long." "Krill are normally found in cold polar seas, but the unusual conditions off Sri Lanka allow krill to thrive in these tropical waters." "So is that why the blue whales are here?" "We see these animals diving, we're counting how long they're down and I've got 100% confidence that these guys are diving deep down and they're finding these really dense patches of krill and lunge-feeding through them." "We've made an animation of how these whales feed at depth." "The blue whale dives to 600 feet, below where the krill are hiding in the gloom." "The whale then powers up through the swarm, gulping its own body weight of water into its ballooning throat." "It then strains out the nutritious krill through its fine mesh of baleen." "Each lunge requires huge effort, but if you have a mouth as big as a blue whale's you can catch so much food that the whole process becomes extraordinarily efficient." "Their size is the secret of their success." "Doug and Didier make one final attempt to get up close to the deep-feeding giants." "It was certainly the biggest whale that I've ever seen." "It just looked enormous underneath me." "I've waited a long time to see a blue underwater, and that was just magic." "Beautiful." "Fantastic." "Today is the best day of my life." "Pumped up on tonnes of krill, blue whales can grow as long as a jetliner, weighing almost 200 tonnes, twice the size of the largest dinosaur." "But, worryingly, the blue's giant size and its giant appetite are now putting it at risk." "We know that climate change is occurring, and that in places like Antarctica the temperatures have sky-rocketed." "We also know that krill has started to decrease, and when you don't have enough food blue whales are going to have trouble surviving." "So as climate change happens, as krill starts to be depleted, blue-whale survival could be in jeopardy." "Blue whales are still endangered, but they are recovering, slowly." "For their recovery to continue, it's not just the whales themselves that will need protection," "For their recovery to continue, it's not just the whales themselves that will need protection, but the seas and the other creatures they depend on." "We may have missed the chance to live with the great dinosaurs of the past, but we do have the good fortune to be sharing our time with the largest creatures that ever lived, these magnificent ocean giants." "WHALESONG" "Subtitles by Red Bee Media Ltd"