"This is a story about a pride of lions... and how they raise their cubs." "...about its defence force of two brothers its mothers and hunters and the animals that decide their future." "Their greatest enemies, nomadic males..." "And their competitors and their constant battle to get food." "This is a story, but everything you're about to see is based on fact." "Events that affect the lives of the cubs - the heirs to the Lion Battlefield." "You're about to see the African savannah like never before..." "This is a virtual world - modelled on 50 years of scientific study." "With new technology we analyse the lion's kingdom in a way that ordinary cameras cannot show." "One hundred square miles under total surveillance with the ability to reveal key zones within the lion battlefield." "Rich grasslands." "A vital water source." "A year round marsh." "Sheltered woodlands." "All enclosed by an escarpment." "This is prime lion territory the homeland of our battlefield pride." "The pride has seven lionesses and 1 0 cubs, all just a few months old and still dependent on their mothers' milk." "Nearby, a large male, father and protector - one of two brothers that defend this pride." "Their job, to keep the cubs alive until they're 2 years old and independent." "But each day brings new threats - and to succeed will take a mix of strength, devotion and sheer luck." "A mile away, the second brother is on border patrol." "Along the edge of his pride's territory, he leaves a string of warning messages for any rivals passing by." "Drenched in his pheromones, the bushes act like beacons - clear no entry signs for other males." "Every 30 metres or so, he repeats the message..." "And this impregnates his feet with scent." "Every footstep lays claim to the land and the pride that lives there." "Each brother leaves thousands of scent prints every day..." "And neighbouring pride males do the same, carving up the land into their separate territories." "But in the no-man's land between, there's space for others to survive... the pride males' rivals..." "Nomad males... waiting for any chance to seize power." "At five years old, these two are serious contenders... looking for a pride to call their own." "For now, they try to keep out of the pride males' way." "If not, they could be killed on sight... but this rarely happens." "The scented boundaries are one deterrent, but pride males have another way of warning trespassers to keep their distance" "A pride brother is warming up for one of the loudest sounds in Africa..." "A wave of aggression radiates across the plains declaring that this land is his - and he's prepared to fight for it." "Every lion within five miles gets the message." "As the wall of sound races across territorial boundaries, heads of neighbouring prides respond... broadcasting their own status and location." "And our pride brother answers back..." "So every pride male knows exactly where the others are - a good way of avoiding volatile face to face encounters." "ln between, the nomads listen - but they keep quiet." "By tuning in, they work out where the pride males are..." "Today they learn the brothers are two miles apart..." "This is the chance the nomads have been waiting for..." "They cross the scent line..." "into occupied territory." "From their lookout, the lionesses are first to spot the intruders - they know only too well what it means." "All their cubs were killed a year ago after a similar attack by the brothers, who are now their mates." "And every successful take-over is the same:" "Remove the old males..." "Kill the cubs..." "And mate to produce cubs of their own." "Today it could happen all over again..." "At 8 years and 200 kilograms, this pride brother is in his prime... but alone he's vulnerable." "The nomads may be novices, but there are two of them." "Younger lionesses hide the cubs, but older females prepare to help the male... and this could swing the odds..." "The nomads are separated..." "They have a simple choice - retreat or die." "The battle's over - and all 1 0 cubs are safe." "The nomads slink away to lick their wounds... lucky to have survived to fight another day." "Until then they're condemned to no-man's land again." "Life in the pride is well worth fighting for... both brothers mate with all seven females." "But victory can only be temporary." "They'll hold the territory only for as long as they are at their peak." "The lionesses are the true landowners - part of a bloodline that may date back hundreds of years." "All sisters and daughters, they've grown up together and have probably never left this territory." "This solidarity is the key to their success - as mothers... and as formidable hunters." "The pride's best hunter leads..." "and others follow." "Two stay behind to guard the cubs." "Hunting together increases their chances of success." "To feed the pride, they need to kill more than 200 animals every year." "They've known this area all their lives... and now they're heading for the marsh a zebra hotspot." "They may have hunted here several hundred times before... lt's as routine as a trip to the shops." "And zebra are on offer today." "The hunters fan out and one breaks off to slip around the side." "Each lioness will now watch for her own chance independently." "The side attacker takes advantage of the scrub to move in closer." "There are no calls, no signals - just an instinctive awareness of each other's position." "With the marsh to the rear, the zebra have few ways out... and one by one, their exits are being blocked." "The lions pay no attention to wind direction... after all, their lingering smell is everywhere." "Zebra are faster than lions... so to run one down, there must be an element of surprise." "The lions need to get within 30 metres." "When the trees end, the side attacker, too, reverts to stealth..." "Four lionesses are now poised to strike if any zebra strays within the 30-metre zone..." "The danger may seem obvious to us... but zebra only see in black and white." "The side attacker blocks the remaining exit..." "The zebra are surrounded..." "and one takes that fatal step too far... ln 30 seconds the females have brought down two adult zebra... bagging more than 200 kilograms of meat for the pride." "The cubs arrive to join their mothers for a meal... but they're not the only mouths the females have to fill." "The males get their perk too... food as protection money." "But hunting doesn't always go so smoothly - and some meals are better at fighting back." "You're now on patrol with possibly the greatest animal defence force on earth." "A 30-strong herd of buffalo - reputedly the most dangerous animals in Africa." "While grazing, they form a close defensive unit..." "At the head is an advance guard - often an older, experienced male." "To the side, the flankers - usually mature females." "At the back, a rear guard made up of younger adults." "ln the centre, the vulnerable calves." "More than 30 tons of tough beef around the herd's soft centre... a strategy designed to ward off lions." "The buffalo stick close together... and spend 20% of their time scanning for possible danger." "Eyes, ears and nose are tuned to any sudden change in their surroundings." "The big males are the main line of defence." "At full charge they can run at 40 miles per hour - and have the impact of a car." "Their horns are formidable weapons... and their hide is more than an inch thick." "Even so, they're not invincible." "They live with the constant threat of ambush." "The herd approaches a danger zone - where woodland scrub meets open grassland." "An ideal location for an ambush." "Most of our pride's successful kills occur close to this boundary." "The advance guard freezes - he has registered the danger." "And his lack of movement puts the others on red alert." "They all stop grazing and focus in the direction of the threat." "Within seconds, the unit is primed and ready... forming a barrier around the calves." "Now they have two choices - stand firm, or retreat." "There is strength in numbers, but mass panic is also a possibility." "The advance guard relies on the backup of others - a lone charge could be his last." "The unit is only as strong as its weakest link - one loss of nerve can trigger a stampede..." "The lions give chase..." "watching for any sign of weakness." "They test the adults and bounce off but an exhausted calf makes easy meat." "But today it's a different story..." "This is not an ambush." "The lions are well fed and resting, using the scrub to shelter the cubs." "ln fact, it's they who have been taken by surprise..." "The cubs are too young to understand the danger." "The buffalo sense their advantage - and defence switches to attack..." "The advance guard spots the cubs - and his fury is unleashed." "Ten confused cubs try to hide..." "but for some it's too late." "Lionesses try distracting the attackers..." "but they're outnumbered..." "When the cubs stop moving, the buffalo lose interest." "The lionesses call to their cubs." "And the survivors emerge..." "But now there are only seven..." "the other three are dead." "The cubs must survive another 1 8 months of hazards like this before they're old enough to fight their own battles." "Life can be hard for the pride, but it's even more uncertain on the fringes of lion society." "ln no-man's land, the nomads have split up to look for food..." "Finding prey is not a problem - but catching it is." "Their thick adult manes mean ambush by daylight is out of the question." "But luckily it's not the only way to get a meal." "Most grazing animals aren't killed by predators, but by illness and disease." "Their bodies could be easy meat for nomads - but they've got to find them first." "And the secret of successful scavenging is speed." "Around our 1 00 square mile battlefield, there may be only one fresh carcass every day." "A wildebeest has died - two miles from one of the hungry nomads - and the race to find it will begin immediately." "But for a lion on the ground, it's like looking for a needle in a haystack the savannah's scavenging elite arrive by air." "A thousand metres up - a griffon vulture has a panoramic view." "Equipped with telephoto vision, it can scan 200 miles in a day." "To find the target regularly, this still isn't enough." "But this vulture is not alone it's part of a squadron of lookouts... one lion against an aerial network of hundreds." "When one of the squadron spots a carcass, it drops to earth at up to 80 miles per hour..." "But it won't be alone for long." "It's just transmitted a signal to other vultures." "This steep dive acts like a signpost in the sky..." "So other vultures read the sign and change direction and in turn relay the message further afield." "This chain reaction ripples outwards, and the flight paths line up from all directions..." "From as far as 20 miles away, birds home in on the same few square metres of ground." "Just minutes since this wildebeest died - and 20 birds have reached the target." "And that's just the start." "This is fast food, savannah style." "ln half an hour, the carcass has completely disappeared." "And the nomad never even knew it was there." "But not always." "Here's another carcass, and another scenario." "This time the arriving air force doesn't go unnoticed." "From the ground, another set of scavengers crack the vulture code." "Hyenas read the signs from miles away, and waste no time." "Follow the vultures, find the carcass..." "Jackals, too, are on their way." "The nomad lion is not so sharp." "The vultures have a head start, but they've got a problem - long-range fliers haven't got the tools to open this large carcass." "Their bills can't pierce thick leather, so the flesh is out of reach." "And every second other hungry mouths are getting closer some, that is." "What's needed is a butcher with a heavy cleaver." "And here he is..." "A lappet-faced vulture." "The king of the carcass." "The lappet has a longer bill than any other bird of prey and strong enough to rip the toughest leather." "As it gorges on the prime flesh, it leaves crucial points of entry for the others." "Now they can tuck in..." "and there's no time to waste." "At last the nomad, too, has read the vulture signs... lf lappets have the cleavers, others have the stripping knives." "Serrated edges slice through tissue and a long neck burrows deep into the offal." "ln minutes they too eat their fill... and all the time new diners are arriving..." "Those full from the first sitting are now ready to clean up - and there's nothing like a nap to help digestion." "For those still on their way, the window of opportunity is shrinking fast." "The first wave of ground troops arrives jackals snatch what they can and retreat..." "They know the heavy mob is right behind." "Once hyenas take over, they'll hoover up everything, even the bones." "The nomad finally arrives and the other diners have to make way." "Most of the flesh is gone, but scraps will keep the nomad fighting fit and ready for the next campaign to win the pride." "The pride don't need to live on others' leftovers." "With efficient killers on their books, they can take it easy." "Over the last nine months the lionesses have been busy." "They have killed 50 wildebeest, 40 zebra and 20 buffalo..." "And the cubs have been transformed and are well on their way to independence." "Dependence has changed to play." "Suckling milk to eating meat." "But one strayed." "And now there are six." "Thanks to a high protein diet, the pride can sleep for 1 8 hours a day one of the big advantages of being born a meat-eater." "The pride lions are not only grassland hunters, to prosper they have to exploit the battlefield's rich woodlands too." "For their territory is constantly changing." "Within every grassy plain is a woodland in the making." "Acacia trees armies of them covering the plains." "Heavily defended and trying to get started." "Where the trees take hold, woodland animals move in new prey for our pride and for other predators - the bush-land specialists." "You're now on board the ultimate stealth hunter... lt hunts alone, waging a one to one battle of wits with its prey." "An elephant shrew is hardly a mouthful - just an appetiser on this sunset sortie." "The caracal lynx is a stalker - and its skills are required by any bushland hunter." "ln this dense undergrowth, there's no advantage in numbers, so pride lionesses, like caracals, seek their prey alone." "Caracals are after smaller prey than lions... and they are equipped to register the smallest clue." "Like all bush hunters, they must listen for what they cannot see." "Ahead in a clearing, a gaggle of noisy guinea fowl..." "Of little interest to a lioness, but the caracal is a champion bird catcher... ln low evening sunlight a long shadow could give the game away... so the caracal stalks directly into the sun..." "Now it's telltale shadow is behind." "The guinea fowl may look exposed, but they have a big advantage." "The clearing offers little cover for a stalker and provides a safety zone around them." "So the caracal must use every trick in the book." "Ear tufts help break up its outline." "From ground level, it's effectively invisible." "lts eyes lock on..." "But to have any chance of a catch, it must get within four metres... the critical attack range." "But at the edge of the clearing, there's no more cover, so all it can do is wait - for the prey to drift into the danger zone." "Muscles twitch in readiness... and its cover is blown... lt has to attack." "One metre too far... and a meal is lost." "But the lioness has been more successful - in fact, the bush can support more lions than the open plains." "But bushland too is constantly changing." "And one savannah force has a devastating impact." "When grass is sparse, these bulldozers wreak havoc, snapping acacia trees like twigs, to reach the rich leaves in the crown." "Where elephants flatten everything in their path, the face of our pride's territory alters once again." "The acacia army isn't beaten... it has reinforcements waiting to advance again." "But it's usually foiled before it can even begin..." "Elephants can destroy a future forest in just a few hours." "And when they're on a mission, nothing gets in their way..." "These bulldozers may be an 'irritation'... but it's another set of neighbours that cause the pride real trouble." "Their network infiltrates every corner of the battlefield - and their headquarters are just outside the pride's territory limits." "Hyenas." "The den may be home to as many as 60 adults, but right now they're mainly on patrol looking for food." "A single adult is left to baby-sit." "The other adults may be hunting up to a hundred miles away - they're born to run." "A hyena's heart is twice as big as a lion's giving it the stamina to cover up to 60 miles a day." "Combined with an acute sense of smell, this means hyenas usually beat lions to the easy meals." "The hyenas' success has bred an intense rivalry with lions." "Encounters between the two competitors are common and dangerous." "Near the marsh, the nomad challengers have returned... and are confident enough to infiltrate pride territory again." "Hyenas are confident too - but where lions are concerned, it's sometimes misplaced." "What lions don't have in endurance, they make up for in sheer strength." "The nomads have come of age - and they'll happily cut their teeth on anyone that gets in their way." "This is no time to taunt them." "One wrong move - no second chance." "Lions and hyenas will kill each other at any opportunity." "But there are plenty more where he came from." "Sheer numbers are what makes them such a thorn in every lion's side." "Little goes on around the battlefield that the hyena clan doesn't know about." "They're quick to exploit any weakness." "And here is the prize weakling." "The cheetah is designed for attack, not defence - and its savannah neighbours know it." "Members of the hyena network are never far away, and this is what makes them such formidable competitors for the lions." "The exhausted cheetah can try to hide the kill from the vulture task force..." "But other eyes are everywhere... and it's much easier to steal a meal than catch your own." "Time after time, the cheetah's speed and grace is trumped by brute force." "Surrender is the only choice." "But hyenas kill their own prey, too." "ln fact, around the lion battlefield, they often kill more prey than the lions themselves." "But hunting in the open is a risky business..." "Out here, strength is always relative..." "A single hyena will always concede to a lion but each disputed kill becomes a numbers game..." "Here, two pride lionesses easily overpower five hyenas." "To match the lionesses' strength, hyenas must outnumber them at least three to one." "The odds are crucial - and they can change very fast." "This time five lionesses have killed a male buffalo - and as usual, passing hyenas are quick to investigate." "It's a trophy well worth fighting for, and without the brothers on the scene, the scavengers may be in with a chance." "It all depends on numbers." "At two to one, the lionesses have the upper hand." "They can keep the hyenas at bay, but they can't keep them quiet." "Their calls of excitement can be heard up to three miles away, and draw other clan members from all directions." "These reinforcements start to swing the odds the other way... and the lionesses know it." "But they don't want to lose their hard won prize..." "But the hyena ranks are swelling by the second - and with no sign of their male defenders, it's just a matter of time..." "This is the real clash of the carnivores... and at 4 to 1 , hyenas win by force of numbers." "But one surrendered buffalo is just a hiccup for the pride." "Their larder is about to fill to overflowing." "The pride is sitting on a goldmine." "During the annual migration, 200,000 grazing animals pass right by the lions' door." "The six surviving cubs are now two years old - and ready to hunt for themselves." "The brothers have done their job well." "But they, too, are getting older... and the nomads are itching for another fight." "The battlefield has everything the lions need... and that's because of one more force of nature - one that every lion, every grazer and every tree relies on." "A force that comes out only after dark..." "This mound is a fortress - a termite city, at its heart the queen, the controller of an event that underpins the entire Savannah." "Without her, there would be no lions." "Every night, her five million subjects go to work - on the most important production line in Africa." "From every termite mound, tunnels take workers out into the fields." "Their mission - to collect dry grass." "They harvest more than all the other grazing animals put together." "The grass is dragged back into the storage pits." "Other workers break it down and send it deeper - to these underground gardens." "It forms a compost, to grow white fungus - a fungus that fuels the entire system." "Every termite eats it and the queen transforms it into brand new termites." "More builders, more harvesters, more soldiers." "As they dig tunnels and collect grass, they mix nutrients into the soil." "Around every termite mound is a nutrient rich zone." "These nutrients grow grass... and grass grows grazers - food for the pride." "But tonight the fortress is under attack..." "From the savannah ramraider - an aardvark." "To survive, it needs 1 0,000 termites every night - and it's got the tools to get them." "But the aardvark isn't alone other raiders are out tonight... and they're not after food." "The termite tower is under attack..." "and soldiers rush to its defence." "The aardvark's sticky tongue scoops up to 30 termites every second." "If it reaches the queen, the colony is doomed." "But thousands of bites become unbearable - this raid will soon be over..." "Above ground, another raid is just beginning..." "The nomads are attacking the brothers..." "and this time it's all or nothing." "A new dawn - and another new era for the lionesses." "The nomads have taken over the pride..." "The new kings will court the lionesses and their two-year-old daughters." "But all the other males have fled." "The old males are mortally wounded." "At eight years their short, violent lives are almost over." "This is the final chapter of the brothers' story." "But close by, a new one begins." "Their sons were lucky to escape the raid alive... and now they, too, must do their time as nomads... a journey that make take four years, until they're ready to try for a pride of their own." "Our lionesses' new defenders may last months or years." "But for now they are the new kings of the lion's battlefield." "It's time to tell the neighbours they've arrived." "This is a story about one of the most inhospitable places on Earth and animals that have to survive here they must find food here and raise their young and protect them from the dangers of the frozen wilderness." "The main danger is others of their own kind - the main ally the constantly changing sea ice." "They navigate here with heightened senses, evolved to lead them straight to food." "This is a story, but it's based on years of research by teams of Arctic scientists." "ln it, we follow the victories and defeats over a single year on the polar bear battlefield." "This is polar bear country - a vast frozen sea bordered by stark mountains, glaciers and barren, snow-covered shores." "It's a white wilderness at the top of the world, and you're about to see it as it's never been seen before." "With the help of computer-generated images, we can see what normally can't be seen and go anywhere the story takes us from the vast plain of sea ice where the bears stalk and attack up to the snowdrifts on the mountain slopes where the birthing dens are hidden," "safe from other polar bears." "It's a world dominated by ice - ice that changes as the year passes." "And it's those changes that determine where a polar bear goes and what it does." "Solid winter sea ice..." "melts in the early spring... to become broken ice floes in the summer." "The ice is where the action is." "All the animals here depend on it... and they live on it or in it or under it." "Where ice, air and water meet there's a place for seals to hide." "And below that is the beluga whale's upside-down world, where the ice is the ceiling and the whole Arctic ocean is a space to live." "The battlefield's enormous." "lts size makes the polar bear a perpetual nomad, trekking fifteen miles a day and up to five thousand a year on ice that's constantly moving." "Our story starts down there in the ice and snow." "It's spring, and a new life is about to see daylight for the first time but not until this female tests the air." "She's been holed up for nearly six months and she doesn't know what's out there now." "There could be danger, and she has something precious to protect." "When she went into the den last winter, she was fifty per cent heavier and alone." "But she's not alone now - she has a cub, one cub." "It's his first experience of the wider world the first moments away from the warm, dark safety of the den." "He was born in January, just over three months ago." "The world he came into was small and cramped." "He had fur, but his eyes were closed." "He wasn't any bigger than a guinea pig." "Outside, it was the depth of winter and blizzards were blowing at a hundred miles an hour." "The temperature was minus sixty Celsius." "Inside, though, it was a comfortable two or three degrees above freezing." "Mother's milk like double cream ensured he put on fat rapidly." "For the next couple of years with his mother there'll be little time for play." "He has to learn how to survive as a polar bear." "He and a lot of others." "All along these slopes, mother bears have been waiting out the winter in their dens isolated from most dangers at a time when they're vulnerable." "But when travelling to their hunting grounds on the sea ice they're even more vulnerable." "Here, the biggest danger is other polar bears - large males, who see cubs as nothing more than potential food." "The mother almost seems to tiptoe she puts some distance between her cubs and the male." "Polar bears are creatures of habit." "Mothers returning to the same areas to hunt each spring to a long-awaited breakfast." "And the wait's not over." "Even after they reach the ice, the trek could take them another two hundred miles." "The ice is constantly shifting." "It cracks and moves." "Huge slabs collide, and blocks are pushed up to form long pressure ridges like miniature mountain ranges." "Mother bears know where their prey will be near lines of weakness next to a pressure ridge." "This mother hasn't eaten since last autumn but has been producing milk." "So, her supply of fat is almost gone." "She needs to eat soon." "She makes straight for a ridge, sniffing constantly." "Smell is her guiding sense." "Entering the bear's sensory world we find the most interesting smells are found near the fissures in the ice." "Nothing is left to chance - she investigates everything." "And this is what she's looking for - a seal." "At this time of year it's under the solid ice." "The bear could be on top of the seal, but with ice between them, it might as well be miles away." "She needs a meeting place and this is it - a tiny breathing hole." "It's a ringed seal and like all marine mammals, it needs air to breathe." "It can stay down for more than twenty minutes, but eventually it has to get its nose to the air or drown." "So it makes holes in the ice." "Using its sharp claws it scrapes out a hollow on the underside which ends in a hole no more than an inch across... lt's just wide enough for a seal's nostrils - this time, just opposite the bear's nostrils." "lts breath has given it away." "But the seal still manages to escape." "Most attempts end this way, but the hunt's not over yet." "The seal has several breathing holes, excavated along cracks in the ice." "All the bear has to do is find the hole the seal will be using next the one leaking the strongest smell." "The seal heads for the hole farthest from the commotion." "The bear tracks along the fissure sniffing its way from one breathing hole to another." "As the bear gets close to the hole being used the smell gets stronger." "The seal needs to surface but the bear is waiting at the last hole." "The seal digs its holes in places where the ice is thin - thin enough for shadows to show through." "Still, it has to take a chance and it escapes again and lives to take another breath." "But there's more here." "It's April, and the seals have pupping lairs in the same area." "Seals give birth on the ice or on land, but ringed seals, early in the season, have their pups in lairs on the ice but under the snow." "Each lair is a simple chamber with an escape hole through to the sea." "The lairs, which hold a mother and pup or pup alone are on the sheltered side of the same ridges as the breathing holes." "Each mother has a territory, where she digs a lair and several haul-out chambers which are used either as emergency boltholes or decoys to fool polar bears." "But fooling polar bears isn't so easy." "It's the smells." "They seep out slowly... percolate up through the ice crystals and drift away downwind and into the nostrils of polar bears who walk upwind... led by the nose to an occupied lair." "Everything the mother does is followed by the cub." "She's hunting." "He's learning." "There's nothing obvious in the snow - no airhole or other giveaway." "As long as the seal doesn't move or breathe hard, there's a chance the bear will pass her by." "But the cub's onto something." "And now his mother is too." "It's a lair - and there's breakfast." "Or maybe not." "As the mother bear breaks in... the mother seal uses her escape hatch and heads for another of her lairs." "ln yet another is her pup, but maybe she can distract the bear." "The cub continues his own search while his mother places her entire body into the hole, blocking out light - it might fool the seal into thinking the lair is still intact and it might return..." "But it doesn't." "She follows her nose to another lair." "She has to check out every trace of seal smell." "Still nothing." "But what's that over there?" "The bear locks on to another target." "The slightest sound will warn the seal, and it'll be down the escape hatch in an instant." "The bear can't see what she's looking for... but she can smell it all right and maybe even hear it." "It is a seal pup - 75% fat - just what polar bears like." "It's crucial to the bear that every step is soundless and, to the pup, that it doesn't move at all." "She listens for the slightest sound and detects a single tiny move." "She breaks through directly over the escape hole." "The pup's cornered." "There's no fight." "She simply grabs the pup's head in her mouth and crushes it." "A baby seal will keep a grown polar bear going for no more than a day." "And normally she'd just eat the energy-rich blubber and leave the meat." "But normally she's not this hungry." "She'll eat the lot." "The cub will soon be having his first taste of seal, though he'll be on milk for 1 8 months at least." "That is, if he continues to survive the Arctic's many dangers - and foremost is the weather." "ln the Arctic, the weather can change in a few minutes." "It may be spring, but blizzards can still engulf the ice and anything on it." "Polar bears, though, are so warmly dressed that they only need to find a hollow in the snow, or dig one, and sleep out the storm." "On an adult bear's rump is a thick layer of insulating fat that tapers out towards its head." "lts fur may look white, but its skin is black and absorbs heat." "ln fact, the fur isn't white - it's translucent." "The thick pelt not only helps insulate the bear, it appears to conduct sunlight to the skin." "The layers of both fur and fat mean that very little heat is lost, however bad the conditions." "A thermal camera, which detects heat loss, shows very few hot spots on a polar bear no more, proportionally, than in the whole landscape." "Even young bears play-fighting on the edge of the ice are almost invisible to the thermal camera." "For them, this is tremendous exertion... but they only lose a little heat from the face, shoulders and loins." "All the heat they keep back is what warms them in the worst of the weather." "ln fact, their entire being is built around saving energy and replenishing it with food." "But as predators they're ungainly - always ambling, rarely running." "They rely on stealth rather than speed." "Early June brings a change in the bears' sea ice." "It starts breaking apart." "The wind causes the slabs of ice to move and where the ice has been flexed by the tide, leads of clear water appear." "The bears' hunting grounds have changed." "The vast white wilderness is becoming a patchwork quilt." "It creates long, ice-free highways for marine mammals from the south who are heading north to feed or breed." "A pod of belugas enters a lead following the contours of the ice." "Like seals, they have to come to the surface to breathe." "But they can't make little ice holes - they need some open water." "Things can go wrong, though." "The temperature can drop suddenly, and ice will reform on the sea's surface." "The leads freeze again and the whales are trapped under a fast-forming ceiling." "But they need somewhere to breathe so they keep surfacing at the same spot, which stops the water there from freezing over." "It's a frantic fight for air, for life." "The whales have solved their problem, for the time being." "They've created a large breathing hole in the ice... and now they have to keep it open until the lead thaws again." "Using their echolocation - their sonar - they search for an escape route." "The whales make sounds that, on bouncing back, give a picture of the way ahead." "But the only picture they're getting is of a sea of ice." "They're stuck under their breathing hole and they'll have to keep surfacing to make sure it stays there." "But before they breathe in, they breathe out and that sends clouds of water and mucous into the air." "The smell is carried on the wind to the nostrils of a young polar bear who starts towards the source of the scent." "The whales' troubles have only just begun." "The bear was a mile away when he picked up the tiniest trace of the smell from a source that not only can't get away but can't stop producing more." "The bear's walking along a corridor of beluga scent that gets stronger as he gets closer." "The whales are too busy just breathing to be concerned about the invitations they're sending out." "And here's another." "The bear can hear the belugas now." "Every time they blow, they give themselves away again." "The bear's nose and ears haven't been lying because now he can see the whales and eyesight isn't his strongest sense." "ln fact, it's about the same as a human's." "The bear has definitely found the belugas and then, in his excitement, he forgets about stealth." "His footsteps reverberate through the ice and the water." "At the best of times, belugas are easily spooked." "Now they're close to panic." "One of them scans the hole." "The bear seems unsure about what to do next." "He's young and has probably never seen belugas before." "If they're anything like seals, though, they're going to have to surface." "The belugas hold their breath and wait for the bear to go." "He doesn't, of course, so they have to take a chance." "They know bears - you can tell by the scars." "But this is a bear that has to think." "How do you catch one of these?" "He seems to have picked one out and he'll try to hit it again and again." "Each time he hits the beluga he rips skin and blubber from the back of its head." "The bear's attacks are wearing the beluga down." "It can't last much longer." "It's surprising, given all the turmoil, that no other bear has turned up." "Well, now another one has." "And this is no novice." "It's that male again." "The smaller bear's too busy to notice." "A large bear can stand ten feet tall - all muscle, claws and teeth." "As the young bear concentrates on his prize the older bear closes in." "If it came to it, he could kill the youngster." "The young bear may have killed the whale, but he still can't get it out." "Finally..." "Now he can eat - although he's not alone." "As the big bear strolls closer, the gulls settle down to wait for their share." "And here's another opportunist - an Arctic fox smells blood, too." "And the young bear smells trouble." "The fox sees an opportunity." "The old bear shows the young one the difference in their sizes while the much smaller animals go straight to the food." "The young bear loses the argument, but at least he's learned how to land a beluga." "Polar bears are quick to learn from observation and experience." "The fox makes its snatch and grab and the big bear takes over along with the other scavengers while the belugas - minus one - still wait for the ice to clear." "And, soon enough, it does clear." "Spring is back." "And when the leads open up this time, it's for the duration of the summer." "The belugas move on..." "They're joined by a whole flotilla of ocean migrants including narwhals, also heading north and a bunch of resident seals going fishing." "The giants are here, too bowhead whales..." "By mid-June... the snow on the ice has started to thaw, forming a network of melt-water pools." "As they grow deeper and wider, the ice gets more slippery." "The thawing by day and freezing by night creates a natural skating rink but not for polar bears they have long hairs between the toes that channel water away like car tyres." "And the pads on each sole have tiny bumps and cavities that stop them from sliding." "And they stay on the ice for as long as they can." "It's from the ice and only from the ice that they can ambush seals." "And the time left for hunting is rapidly disappearing." "ln early summer in the High Arctic, the sun doesn't set which means a twenty-four-hour day for hunting as long as the ice lasts and it won't last much longer." "Twenty-four hours of sunshine is seeing to that." "The ice platform the bears use for their attacks is slowly disintegrating." "As the weather gets warmer, a polar bear gets hungrier and its main hunting advantage disappears from under its feet." "There's no possibility of catching seals now not if a bear loses the ability to surprise one." "Naive seal pups can be caught out, but not on this occasion." "When the tiny ice islands have almost melted away, a bear can find himself a long swim from the coast." "Of course, there are always other animals he could try for." "Not walruses, though." "They swim too fast and could kill a bear in the water, though a walrus pup is a consideration." "Not now, but if one hauls out on the shore... lt's not that polar bears aren't at home in the sea." "Some will swim miles for no obvious reason." "They use their large forepaws to dogpaddle and trail the hind legs as rudders." "A lot of bears will travel north with the receding ice, so they can keep hunting from the ice edge but a bear that's left behind will have to spend the summer on land and will try to get by mainly on its own body fat." "ln summer, an ice bear becomes a water bear or a land bear." "During summertime the living isn't easy - polar bears get little to eat." "But not eating for a couple of months requires energy to be conserved, and that's easy enough." "It just means doing nothing." "But if starvation looms anyway, polar bears can be surprisingly adaptable almost as adaptable as the acknowledged master of the art, the Arctic fox." "These cliffs are fifteen hundred feet high and as sheer as if sea ice were turned on its side." "But there's food up there, if a bear can reach it." "Hundreds of thousands of guillemots are nesting on the cliff-face, but as their chicks mature, there's an increasing danger from gulls." "It's safer for the fledglings to be out at sea." "The trouble is, they can't fly." "They have to glide - glide over enemy territory." "Over polar bears foxes and gulls all waiting for them to ditch short of the mark." "A gull may have snatched that one, but the fox knows there are more coming..." "While the bear still seems to be thinking about going up, the fox is concentrating on what's coming down - food, straight from the sky." "ln summer, an Arctic fox doesn't need a polar bear in order to get a meal." "As for the bear, better to go back to doing nothing." "When their drifting ice floes have melted, some bears find themselves trapped on barren islands but the young bear has landed on the mainland, where there's at least a chance of finding something to eat." "It's truly warm now, and the bear's winter insulation could be a real handicap." "Everything about his body is designed to keep heat in, even when the air temperature reaches thirty degrees." "A polar bear never sweats, and so one that's too active can overheat." "Heat's lost from the muzzle and inside of the thighs and there are thin strips of muscle rich in blood vessels from which heat can escape." "The young bear copes by moving slowly and sleeping as much as possible." "But he still gets hungry, and there's something interesting down there." "The smell's familiar." "It's the smell of belugas - hundreds of them." "They come to this shallow estuary to slough off their old skin." "And because river water is a little warmer than seawater, they bring their newborn calves here." "For belugas, it's like being in a warm communal bath, but for a bear, it's more like... beluga stew." "Sometimes a beluga - busy rubbing its skin off on the river gravel - is caught by the tide and will strand helpless until the tide returns... or something worse happens." "It's the bear or the tide, whichever gets there first." "The beluga still has scratches from the attack at the breathing hole, but this time it could be far more serious." "The tide is coming in." "It only takes one footstep in the water for the bear to give himself away." "This was teeming with belugas a minute ago." "But now they're teeming somewhere else." "It's just another example of how hard it is for polar bears to hunt without the help of sea ice." "By autumn, starvation is a real possibility." "What little food the bears have found is hardly enough to keep them going." "But not everything that happens is the same every year." "There can be surprises." "This autumn, as luck would have it, the sea ice is late in forming, and bears aren't the only ones to feel the consequences of that." "This year's phenomenon starts with a strong smell of seals in the air." "The cause is just over there at the water's edge." "Walruses - hundreds of them." "They should be out on the ice now, but like the bears, they're stranded on land." "As hard as they usually are to kill, they seem vulnerable now, and bears are coming from miles around including the intimidating giant." "Blubber, and lots of it if only it would stand still and not threaten to fight." "Walruses aren't animals that polar bears are used to dealing with." "Somewhere, somehow, there has to be a way into this wall of blubber." "There are pups in there." "There's one." "There's another one." "Another." "But how do you get the pup away from the big ones?" "It's seems to be more than one bear by itself can manage." "But the bear isn't by itself." "Other bears have picked up the scent." "Polar bears are more than just solitary animals - they actively dislike each other." "But they're all very hungry now, and there's an awful lot of food cornered here." "They're circling like vultures." "The only trouble is, these bodies aren't dead." "Even the mother is here with her cub." "The bears have backed the walruses into the water." "But can they organise an assault?" "The mass attack, uncoordinated as it is, seems to be working." "The walruses are breaking ranks." "The bears have singled out the young, the old and the unhealthy - especially the young." "Now they're closing in." "There's the objective..." "Confusion among the walruses." "The wall of blubber is breached." "A pup goes." "Another one." "But as soon as a kill is made, the carcass is dragged away so that other bears won't steal it." "It's a victory, and it's a massacre." "The beach is covered with walrus meat and bones." "Because there were so many bears, they're all feasting at a time when they might be expected to starve." "There are even leftovers for late arrivals." "It's highly unusual for this many polar bears to be gathered in the same place." "For a moment in their lives, they stopped being solitary... young bears, old bears, males and females they've all fed alongside each other." "And because there was plenty for everyone, there were no fights." "And they will all live to see the sea freeze again and to sniff for seals at their breathing holes." "Now the gathering breaks up, and each bear goes away to wait for winter, alone." "The surviving walruses are waiting for winter, too." "To avoid another slaughter, they need ice to haul out on, by leads and patches of open water." "As a few of the remaining walruses bob in the water offshore... the first snow of winter settles on the beach." "The sea ice will be here soon, and the young bear bides his time." "He'll be sustained for a while by the walrus massacre and isn't desperate to eat." "He's just wandering and waiting on the beach." "Then he sees something." "It's a female polar bear - one that didn't live to see the sea freeze." "He almost seems to recognise her." "Why did she die?" "Was it old age, starvation or was it something else?" "Could we be affecting life in the Arctic?" "ln some parts the ice forms later every year." "That's because of the worldwide rise in temperatures." "Without ice, a polar bear can't hunt." "Without ice, there can't be polar bears." "It's October now, and the sea should freeze over in a few days." "But throughout the Arctic, that's not happening." "What ice there is is retreating and thinning." "But right now, in early winter, all the polar bears except pregnant females should be out there, walking on ice." "And eventually the ice does appear." "After a long hard summer the young bear is back in his element." "He has coped." "But how long will polar bears be able to when man-made pollution and unnatural heat are seeping into their battlefield?" "This is a story about one of nature's top predators and how it uses its stamina, intelligence and tenacity to survive." "For the first time, you'll have an extraordinary view of the wolf and the wolf's world." "Through the eyes of its leaders and their family - the pack - you'll witness the stress and success of their life as a team." "And see how the events in the pack's life take place here, in their territory." "A place that's worth protecting in any way they can." "You'll join them in their constant search for food - food big enough to fight back..." "And watch as they battle their bitterest enemies - their neighbours - and their other fierce rival, the grizzly... encounters that threaten their future." "This is a story, but everything you're about to see is based on fact." "The strength of the wolf is the pack, but is this pack up to the challenges of life on the wolf battlefield?" "The Rocky mountains of North America..." "home to hundreds of wolves." "A wilderness that stretches for thousands of square kilometres." "With special technology we can analyse the wolf's world in a way that ordinary cameras cannot show." "Creating a virtual reality..." "From this view, we can focus in on just two hundred square kilometres - our pack's domain." "Revealing the key zones within it:" "Lowland plains... with ridges above for lookout points..." "A river that flows all year round..." "Dense, forested slopes for cover..." "And all this flanked by towering mountain peaks." "Prime wolf territory, currently occupied by our Battlefield pack - the Jets." "This tightly knit team of seven wolves is led by the alpha pair - a big, silver male and his smaller, black mate." "The alphas are mother and father to four adolescents - all born just under two years ago." "The seventh wolf, an adult male, is an outsider - and pack underdog." "All the wolves are expert hunters." "They need to be." "It's January and on the face of it, the wolf's world looks lifeless..." "There's deep snow on the high slopes and it's minus 2O degrees Celsius." "Most small mammals are hibernating and are off the menu." "Only larger prey, like buffalo and elk, are awake and available." "But they're too big for a single wolf to tackle, and they're always on the move to find enough to eat." "So, the Jets must stick together, and be nomadic too." "Wolves are built for long-distance travel..." "Their long legs, big lungs and hearts give them a cruising speed of eight miles per hour." "They can average fifty kilometres a day - and clock up three laps of their territory a week." "But how do they find their way around such a large area - and where do they start looking for food?" "It's always one of the alpha wolves who leads the way." "The alphas have held this territory for almost three years." "Experience has taught them that the herds don't move randomly." "They visit favourite feeding areas at certain times of year - and they always follow the same routes." "Wolves don't move randomly either which suggests they have a mental map of their territory, an in-built route-planner that helps them visualise where they are, and which path to take to intercept their prey." "A wolf's brain is thirty per cent bigger than a dog's - and it's this extra brainpower that helps the wolf navigate so effectively." "The pack's trails make up a closed circuit inside their territory - but some routes connect with their neighbours' trails, creating a huge network of wolf highways for thousands of square kilometres." "With so many other wolves in this area, it's vital our pack has exclusive rights to its territory and food supply." "Somehow, the wolves must protect what's theirs because next door they have the neighbours from hell!" "ln just four years, this rival pack has grown unusually large." "There are twenty-two of them." "The Big Pack's alpha wolves have raised many youngsters - and none of them have left home yet." "There are problems with a pack this size." "They can't afford a day without a kill." "And to find enough food, they need a big territory." "This makes the Big Pack dangerous... sooner or later they could invade the Jets' living space." "Our pack's best defence is to engage in chemical warfare." "The agent they use is scent." "It's a clear warning to outsiders to keep out - a signal all wolves recognise and ignore at their peril." "Wolves leave a scent mark every hundred metres or so along their trails and boundaries." "These signposts are unmissable, and they last for weeks... ideal for animals constantly on the move." "And the source material is portable and easy to produce." "As the urine spreads and evaporates, it releases the wolf's personal perfume." "Scent marking is the responsibility of the two pack leaders." "All they need to do is refresh each mark as they travel - leaving a trail of reassuringly familiar, smelly hotspots." "A wolf has more than two hundred million scent receptors in its nose, making its sense of smell ten thousand times more sensitive than ours." "Along its territorial boundaries, each pack goes into overdrive, responding to the threatening smell of its neighbours." "The stakes are so high here that wolves use droppings, as well as urine, as a double deterrent to intruders." "The alphas encounter and produce a scent signal every two minutes." "By doggedly reinforcing their frontline, they try to keep their territory secure leaving them time to relax and socialise." "The pack's social life revolves around the alpha wolves..." "They dominate more by strength of personality than by brute force." "They use facial expressions and body language to keep everyone in line and show how they feel." "Dominance and submission help keep the peace." "These tussles may look aggressive, but they can simply be a way of reinforcing bonds and reassuring each wolf of its place in the pack." "The adolescents are almost full-grown... but still too young to leave the pack." "For them, free time is playtime." "Company is vital for a wolf... separation can lead to disaster." "Last spring, the alpha female was left alone..." "With prey in very short supply, the pack was forced to split up to search for food, leaving her at the den to guard her pups." "After a week, she faced a harsh choice - leave her pups or starve." "Even underground, pups can be vulnerable... but in the end the mother's hunger drove her to take the risk." "A grizzly's sense of smell is as powerful as a wolf's - and after a long winter without food, it has a craving for protein." "This time the wolves' attack came too late..." "With her pups dead, the female's only chance to breed last year was dashed." "Teamwork is the key to wolf survival." "Even if you're the underdog, it's best to be one of the gang." "Life on his own would be lonely and short." "Operating as a pack is also the only way wolves can hunt big animals effectively." "And it's always the alpha wolves who take the lead." "The Jets haven't eaten for four days and now they're totally focused on finding food." "Each wolf taps into its mental map, which isn't just a 3-dimensional route-planner, it's also a picture catalogue - a menu of prey animals available." "Any one is an attractive target." "But ranging in size from fifty to a thousand kilos - none is easy meat." "Bighorn sheep are fairly small, but live in groups, have big attitudes - and serious headgear." "Others, like moose, are solitary and roam territories of their own." "Every few weeks, the wolves check up on them to see if they've become sick or injured." "Who to hunt and when are key to a successful kill - and their mental maps help them select animals that could offer the easiest pickings." "Top of the menu today are elk... and the wolves must use their mental map to work out how to intercept them." "Years of following migrating herds all through the changing seasons mean the wolves have memorised the elks' routine." "ln January, they can predict the elk are heading for the valleys to the east, forty kilometres away." "Just getting here has taken seven hours." "Now they find a vantage point to keep the elk under surveillance." "The best strategy for hunting big animals is to select the most vulnerable." "Usually by midwinter, with food harder to find, some pregnant females will be struggling..." "As well as being almost four months pregnant, they have their seven month-old calves with them." "The youngsters are weaned, but still stay with their mothers for protection." "Wolves are always interested in calves, as they're more likely to make mistakes." "But so far, this winter's been mild and food in this valley is still within easy reach." "The females look well fed and healthy - and so do their calves." "Has our pack come all this way for nothing?" "And there's another problem - the Jets are only four kilometers from their northern border." "There's a danger the elk will drift across into Big Pack territory." "From their position above the herd, the wolves may be able to spot a weak animal." "After hours of waiting, it's the alpha male who makes a move..." "They've seen no obvious soft target, so it's time to take a closer look." "They make no attempt to hide as they approach and the elk know they're there." "The wolves split up and assess the herd, looking for the wounded... the lame... the weak." "Weakness is easier to see if the elk are moving;" "easier still if they're running." "The alpha female has picked out a nervous calf... at this age, it's had little experience of wolves and its confidence can be easily shaken." "Now the elk are forced to run, but the older animals know what to do." "They run towards the front and in the middle of the herd - furthest away from the chasing pack - where they're less likely to be spotted if they are carrying an injury." "The wolves can run as fast as elk, but after going without food for several days, will they have the stamina to keep up?" "The elk head for a frozen riverbed where drifting snow is deeper than on the slopes." "It's not a problem for the long-legged elk, but it slows the wolves and saps their energy..." "The wolves clear the drift and accelerate to forty miles per hour." "The herd tries a different strategy and heads for the woods." "They're much more sure-footed on the uneven surface of roots and hollows around the trees..." "Here, the wolves might find it tough to keep up." "And perhaps among the trees, it's harder for them to single out a target?" "But the wolves are still focused... seeking to match their mental picture with a victim." "The elk now turn for high ground - and use the slope to pick up speed and shake off the wolves that way." "lnvisible to them, the herd runs straight through the pack's territorial boundary, marked by their scent." "But will the wolves cross their own frontline?" "They don't hesitate..." "the stakes are just too high." "They're in no-man's land now, and just a kilometre from the border of the Big Pack's territory." "Even after five kilometres, the wolves still push the elk..." "The alpha female's locked onto a target..." "But the elk looks young and fit, so what can she see that we can't?" "ln fact, the elk's lame - and by slowing down the action, we can analyse her injury." "Her right hind leg looks deformed and she can't fully extend it as she runs..." "Her hock joint appears bigger than it should be... lnside there's a bony growth over the joint." "It's like arthritis, but in such a young elk it's probably been caused by a kick or fracture." "And it's now become a life-threatening handicap..." "The younger wolf is lighter and faster than her mother." "But the elk weighs three times their combined weight... and it will take both of them to bring her down." "Hamstringing is an option - but it's not the quickest way to kill... and one kick could be fatal for the wolves." "The elk's almost running on empty, but a huge dose of adrenalin gives her a burst of incredible strength..." "Finally, the elk loses the fight..." "But our pack's in alien territory... and its presence hasn't gone unnoticed..." "The Big Pack is just two kilometres away." "It too was shadowing the herd..." "and spotted the elk running." "Howling helps them muster and delivers a spine-chilling warning to the Jets." "No time for squabbling over the best cuts now... they rip into the rump and belly - wolfing down as much meat as they can." "A wolf's stomach can store fifteen kilos, to digest later..." "Just as well..." "because the big pack's here in force." "Our alpha male is his pack's chief protector... but will he lead them to defend their kill?" "Outnumbered 3 to 1 , they have a simple choice:" "back off or die." "After all our pack's hard work, it's their rivals who benefit..." "The Jets retreat behind their frontline, but at least they're safe to hunt another day." "It's February, and this is the first fresh snowfall for months." "The worsening conditions and deepening snow could make life harder for all the grazers." "But what's bad for the wolf's prey could benefit the wolves... and right now, our pack needs a boost in fortune." "The alpha female is ready to mate - which means a new chance to expand the pack." "The alpha pair spends most of her six weeks on heat together." "This close bond is vital." "She'll need his help to raise their pups." "Wolves mate for life and it's in the alphas' interests to be the only breeding animals in the pack." "It guarantees that all food and attention are devoted to their pups." "At just under two, the adolescents are still too young to breed." "When they are ready to start a family, they'll have to leave the pack." "For all the wolves, the breeding season is the most stressful time of the year." "But it's only at kills that tension turns to open aggression." "To stay in peak condition, both alphas need and demand the richest pickings." "The others must wait their turn..." "Both the alpha wolves' stress levels are at boiling point." "The male picks on his sons." "And his mate attacks her daughters." "These intense outbursts keep the alphas' stress hormones sky-high, but also keeps them on top." "And alpha-aggression suppresses the others' sex hormones, making them even more subdued." "Whatever happens, the best thing to do is just grin and bear it." "If there was more than one breeding season a year, there'd be constant antagonism within the pack - and that would threaten everyone's survival." "It's late March." "The deep snow and freezing conditions of the last few weeks have increased pressure on all the wolf's prey." "Food is very hard to find... and many animals are living off their fat reserves." "The weak are getting weaker." "And it's up to the Jets to find them." "But as always, they have a battle plan." "They're heading south to a huge area of forest." "With its open river course, this location offers both hiding places and food for one of the wolf's most daunting prey - moose." "There are six moose living within our pack's territory." "The wolves visit each one every few weeks - to monitor their condition." "Their decision to come to this forest isn't a random one." "Last time they tracked the moose that lives here, they detected signs of weakness." "Now they're back, to see if there's any change." "They wouldn't stand a chance against a healthy moose, but a sick animal is a different story - and they've come more than thirty kilometres to find out." "But first they've got to track it down." "The wolf hunts just as well by night as in the day." "To help them see in low light, wolves' eyes are designed for night vision." "Their eyes shine because a mirrored layer on the retina reflects all available light back into the eye." "The clear lens in the middle sharpens the image." "So to a wolf, the forest doesn't look so impenetrable... and its peripheral vision is sensitive to any sudden movement." "The wolves split up to search by sight and smell..." "They can sniff out prey up to five kilometres away." "All it takes is a single molecule of moose scent in a quadrillion of air molecules to help them identify their target." "Up ahead, the solitary moose is looking for food." "It's over two metres tall, and weighs three hundred kilos - a formidable opponent for a pack of wolves..." "The moose has selected its surroundings carefully - the dense trees are a good protection against a wolf attack." "And it too has finely tuned senses..." "But wherever the moose goes, it can't help leaving telltale clues - which could help the wolves build up a picture of their quarry." "Millions of its hairs and skin cells constantly shower the ground..." "Every step creates a scent print from glands in its feet..." "And thanks to its high fibre diet, even traces of gas can linger..." "Just two kilometres away, the wolves walk into the moose's scent." "For a short while, they stand rigid and point in the direction of the incoming scent." "They take long, deep sniffs to identify the smell." "Now they're all locked onto their target, they stalk upwind." "The first clue - a depression in the snow where the moose rested just an hour ago..." "The alpha male investigates with quick, short sniffs." "He inhales huge volumes of air straight up his nostrils and onto millions of scent receptors." "Blowing hard back on the area dislodges even more scent particles, mingled with hair and skin cells." "Each one could betray its owner..." "The heavy skin and hair loss indicates the moose is badly infested with ticks - and probably very weak." "A second clue - the moose's tracks." "The male's nose scans the footprint for the most concentrated odour." "This time, as he exhales, he blows air away from the scent through slits in the side of his nose, so it isn't diluted by his breath." "There's a hint of pus - suggesting the moose is injured and may well be lame." "Their attention shifts from the ground to the branches above." "They're looking for a trace of moose saliva... this is it." "A foul stench suggests the moose has rotten teeth - a sure sign that it's old." "And if it can't chew properly, may well be starving." "All the evidence confirms the moose is an ideal target but the wolves still need to get close enough before they strike..." "But given all the clues, this moose is all but dead on its feet." "It's late April and the wolf battlefield is changing." "Rising temperatures stimulate new growth and release hibernating animals from their long sleep." "The thaw gives the wolf's prey a welcome respite and offers the promise of fresh food." "But spring isn't always an easy time for wolves." "ln the big pack, there's mutiny..." "Fighting like this - not linked to the breeding season or a kill, is very rare." "It's happening because the pack has grown too big - the alphas' sons and daughters are now old and bold enough to challenge their authority." "If they kill their parents, one of the youngsters may get a chance to rule this territory." "But force alone isn't enough." "Do any of them have the strength of character to be a leader?" "..." "The big pack's in big trouble." "Life couldn't be more different for the Jets..." "The alpha female has produced three pups and, this time, she's got more support - one of her daughters is on den-duty." "After last year's tragedy - her mother's chosen the den site carefully... lt's on a steep ridge with excellent views and well inside the pack's territory." "It's also thirty metres from a stream - a vital resource for a nursing mother." "She needs plenty of fresh water to produce more milk." "The newborns induce a surge of puppy love in all the wolves - male and female." "This makes the pack want to care for the pups and keeps them working as a team." "And right now, all the other members of the team are ten kilometres away." "This spring, there are plenty of large animals inside their territory - after a hard winter; some are too weak to offer much resistance to a hunting pack." "Their job is to fill their bellies and take food back to the den for the alpha female and her daughter." "From now on, they have to find enough to eat for everyone and keep the pups safe - it's survival at its simplest." "But on the wolf battlefield, fortunes can quickly change..." "Just forty kilometres from where the Jets are feeding on their kill, this large river has washed up a meal for their neighbours." "But the wolves aren't alone." "And the young bear's just as desperate for food..." "These five young wolves are all that's left of the big pack." "They are near starving and can't afford to lose their carcass, but can they defend it?" "As part of the big pack the wolves were efficient killers." "But now this small band of youngsters struggle to fend off a young bear." "If this is the best they can do - these wolves will lose their battle to survive." "Perhaps the big pack has finally had its day, but on the wolf battlefield, the seasons march on." "It's early August and the grazing animals are making the best of the rich menu available during the short, Rocky Mountain summer." "Both youngsters and adults will need to be in prime condition for the long winter ahead." "Now, at three months old, our pack's pups are still the centre of attention... and old enough to leave the den." "Already they're showing the tenacity and character they'll need to survive." "The alpha pair's strong leadership has paid off." "And the pack's teamwork has given the three pups the best start in life." "Together, they've got through the setbacks and challenges of the last year - and started to lay the foundations for a bigger, stronger pack." "The pups are part of the team and ready to take on the world." "It's time for the wolves to return to their life on the move..." "And the pups can begin to learn the skills they'll need to play their part in killing for the pack." "The alpha female and her mate now have another generation to defend their future." "And with their neighbours spent, ahead of our pack lies a land of opportunity." "On the Wolf Battlefield, it's time for the Jets to draw a new frontline." "This is a story about a hungry mother..." "A female tiger shark and the extra-ordinary world she lives in." "Right now she's got to find a meal... she's pregnant - there are forty babies in her belly... and if they are to survive, she must eat soon." "But she has rivals other tiger sharks they're chasing the same food." "And there are other hunters out today sharks with a range of senses we can barely comprehend." "They're all competing in a world beyond our perception." "This is a story, but everything you're about to see is based on fact." "For the next few months these waters will become a Shark Battlefield." "You're about to see a tropical island like you've never seen it before." "A virtual world - based on fifty years of scientific study." "Within it, we can travel to any point on the island revealing our shark in ways that ordinary cameras cannot show." "From the outer reef edge, we take you to... the channel a highway between the open sea and sheltered lagoons." "All around the island is a ring of coral the reef flats there's no richer concentration of marine life anywhere on earth." "Protected from the stormy ocean by these reefs, there's a large, shallow lagoon." "It's a feeding and breeding area for residents and ocean visitors alike." "And where sand has built up on the reef flats there are coral cays..." "nest sites for millions of seabirds." "These are the critical zones in this natural battlefield." "And for the next three months they'll be the hunting ground of our female tiger shark." "She's about four metres long and twenty years old... her tiger stripes have begun to fade with age." "Along with her there's a gang of remoras or sucker fish that come and go looking for scraps." "She's now nine months pregnant... three months from giving birth - but her developing pups are in danger." "She hasn't fed for some time and if she doesn't find a meal soon, some may die before they're born." "Finding food isn't easy." "The water is thick with plankton and for us visibility is restricted but a tiger shark's eyes are ten times more sensitive than ours." "Vision alone won't help her anyway, especially when the nearest easy meal is ten kilometres away." "A dead turtle floats near a breeding beach... a hundred kilos of food - just what our pregnant mother needs but she'll have to be quick." "Other tiger sharks are in the area each one is focused on the need for food." "To track down this meal, eyesight isn't going to be much use." "We've now entered the shark's sensory world." "We see the turtle as a source of tantalising smells." "As it decomposes, telltale scents diffuse into the water." "Some scent molecules sink down into the deeper currents, while others spread out quickly at the surface." "These smells broadcast news of the turtle's death... and its location news that travels on the current at about four kilometres per hour." "Soon the dead turtle detection zone covers ten square kilometres and our female tiger shark is perfectly designed to find it." "She can read signs in the water that we cannot see unless we switch back into scent world..." "Now we can see the clouds of background smells that seep out of the reef, and dominate our tiger's life." "She channels water through her ultra-sensitive nostrils, testing it for interesting odours twenty-four hours a day." "Two-thirds of her brain is constantly at work analysing the messages received." "ln effect, she is reading a chemical book dissolved in the water... a book that tells the story of what lies upstream." "And this is crucial if she's to find the turtle." "But she's not alone." "There's no prize for runners-up..." "To increase her chance of picking up a lead, she zigzags back and forth across the current." "This enables her to test a greater expanse of water than if she just swam straight ahead." "She checks the deeper water near the sea floor, where heavier scent molecules may lie then swims back to the surface... always covering as large a sample area as possible." "She's getting closer to the turtle's scent trail, but unless she actually swims across it, she won't know it's there." "Just a few metres to the left or right and she could miss it... and miss out on a meal." "She's found it, and she cuts across the flow." "She swims back and forth across the current." "As one nostril leaves the odour trail, she turns back into it she turns again, she mustn't lose this vein of scent... her unborn babies are depending on what may lay at the end of it." "She swims up the scent corridor as it meanders back to its source... back to the dead turtle." "But is she already too late?" "Other tiger sharks have hit the jackpot first." "The tigers' saw-like teeth can slice through flesh, shell, even bones." "More scent cascades into the water and more sharks arrive to fight for the prime cuts." "One turtle won't last long." "It's thirty minutes since our female hit the scent trail... but there's no way she could know if she's following old news." "The meal is over and the few scraps left behind are snatched by smaller reef sharks." "It's back to square one for our pregnant female..." "She searches around the clock, circling and re-circling the island..." "She can swim non-stop up to ninety kilometres a day." "But after a week she's still failed to find food, so her search has a renewed urgency." "But it's evening, and an hour before dark there's a race for the safest places to spend the night." "Our tiger shark's too big to nose about among the corals, so she heads out over the reef edge to deeper water." "The reef fish are safe from our tiger... but what will the night bring?" "On moonless nights, there's little light down here." "Even with the latest night-vision technology, it's hard for us to see anything." "But there's a shark that's perfectly at ease in these black waters... lt hunts in total darkness..." "using senses hard for us to understand." "It's a whitetip reef shark - a specialist reef hunter." "Even with no light at all, it weaves its way between the jagged corals without a scratch." "It's guided by a sixth sense that we don't have." "It has sensors that detect movements in the water from a couple of metres away." "It's as if it is surrounded..." "by a pressure sensitive bubble." "The sensory cells run down each side of its body and over its head... and they're known as the lateral line." "It's a kind of 'touch-at-a-distance' - like having a second skin a short distance from its body." "The shark can even feel when its own pressure wave becomes distorted by the coral walls." "So it can hug the reef without colliding with it investigating every nook and cranny for hidden fish." "Even if they've wriggled out of sight deep in the coral fortress, fish still give themselves away... they can't do anything about their scent." "Odours build up in their hideaways and tiny clues seep out across the reef..." "Courtesy of its lateral line, a whitetip can press its nostrils close in to the corals." "It's missed this tiny trail of fish odour." "But there's more than one shark hunting tonight whitetips hunt in gangs." "When they do detect the whiff of food, they've got what it takes to get in really close." "The whitetip's wedge-shaped head can squeeze into any crevice... its thick skin, covered with millions of tiny teeth, acts like a chain mail suit, protection from the sharpest corals." "By folding its large dorsal fin against its back, it can squirm even further into holes... and by manoeuvring along the seabed with its pectoral fins, it can reverse back out again." "Our tiger shark's not so flexible... but then, she is considerably larger." "A whitetip that strays too far from the reef could end up as her long-awaited meal but now the whitetip gang has picked up the scent from a potential target and they flush out a fish..." "...a rock cod." "It's now caught in a game of cat and mouse - and don't forget this is all taking place in complete darkness." "As it makes a dash for cover, the fish leaves something behind, and the shark follows it." "Each time it thrashes its tail, it leaves a trail of disturbance... and this is detected by the shark's lateral line sensors." "The rock cod's best chance is to stay calm and move slowly until it can find another hideaway." "The whitetips probe the darkness." "They know there's something here, if only they could pinpoint it." "The sharks that follow in the fish's wake can also smell its scent trapped in the turbulence it leaves behind." "The rock cod seems to live a charmed life, but the odds are stacking up against it." "All it will take is one false move..." "The commotion trips the lateral lines of any sharks nearby, and they join the frenzy." "But they need to watch their backs... like all sharks, tiger sharks have lateral lines too." "Predators can soon become prey - the balance shifts throughout the night." "By morning our tiger has still failed to find food." "She's moved into the lagoon, heading for the fringe of mangroves and she's in a hurry..." "She's detected an irresistible smell... and it seems to be coming from the shallow waters around the mangroves." "But now she can't go any further it's too shallow... just another a dead end in her search for food." "The smell is coming from another mother - a much smaller lemon shark - giving birth." "Like most reef sharks, she's swum in as shallow as she can so that her newborn pups are out of reach of larger sharks." "Minutes after birth, each pup makes a beeline for the safety of the mangroves." "For the moment, these youngsters are safe here from the tiger shark." "But on the other side of the lagoon, there's more potential food arriving." "They're stingrays, riding the incoming tide... heading for the island's central lagoon." "Here, they search for worms and shellfish buried in the sand and then disperse to find a resting place where they can simply disappear." "Their sandy camouflage breaks up the outline of their bodies." "Nothing will find them here... or will it?" "An even more sinister visitor is entering the lagoon." "It's hammerhead shark - a great hammerhead, more than three metres long." "lts head swings from side to side, producing a strange double vision... first one eye points forward, and then the other." "lts hammer-shaped head also works like the hydroplanes of a submarine, so it can turn on a sixpence, or dive rapidly to the bottom." "Unlike our tiger shark, its speciality is hunting on the ocean floor." "With smaller pectoral fins than other sharks, its belly almost skims the sand." "And to detect its prey it has an extraordinary seventh sense, one that can find stingrays hiding under the sand." "The underside of its head is lined with receptors that detect electricity... including minute pulses radiating from the gills of its prey." "The stingrays may be lying still and out of sight but they will give themselves away by the very thing that keeps them alive." "When a hammerhead's about, breathing can be fatal." "...three stingrays, hiding in an area the size of a football pitch, will not be easy to locate, especially as the shark must detect the very weak electric fields generated by the activity of their gills these electric fields can be picked up from twenty centimetres above the sand so the shark must be directly above its target the hammerhead is systematic in its search it sweeps its head from side to side, like a metal detector," "covering as much sea floor as possible... its electrical sensors are so sensitive, it's the equivalent of detecting a household battery from halfway across the Pacific Ocean effective quartering will ensure that the stingrays have no place to hide... lt's now close to a target." "It tightens its search pattern." "The shark uses its hammer to pin down the ray." "It disables its prey with a single bite out of its wing." "The commotion in the water alerts our tiger shark... and she comes in to investigate." "Scent oozes from the dying prey." "The tiger shark locks in." "A pregnant female might do better to avoid this clash of titans." "But the smell of food is just too tempting..." "Anyway she's bigger - usually the last word in shark body language." "The hammerhead gives way." "Our tiger cautiously nudges the stingray's body." "Taste receptors in her mouth check out if it's edible before the first bite." "It's a successful heist though no more than a snack, it's enough to be converted into some food for her forty unborn babies." "A nutritious fluid oozes from the lining of the mother's womb, bathing the babies in a fat-rich milk." "They drink and grow but only if their mother manages to eat for forty..." "Food is what drew our female tiger to the shark battlefield in the first place." "It's the three-month breeding season and the island literally teems with life." "Millions of seabirds come here... with no predators on land at least, the island is a perfect place to nest." "As more prospective parents fly in, there's hardly room to touch down but this carpet of sooty terns provides surprising benefits for sharks." "Each day the parent birds bring back hundreds of tons of fish and squid." "They and their babies process it and turn it into something else that helps keep everyone well fed." "It's guano!" "Layer upon layer of seabird fertiliser." "All it needs is water and a good stir." "The guano run-off mixes with nutrient-rich upwellings from the deep sea floor creating exceptionally fertile waters - the basis of a busy food chain." "The nutritious soup feeds plankton..." "microscopic plants and animals, which are the staple diet of small fish - which in turn are eaten by larger fish - hundreds of millions of them... and at the top of the chain - sharks - hundreds of them." "Tiger, black-tip and bronze whaler sharks invade the outer battlefield, after a gigantic shoal of anchovies." "Bronze whaler sharks are speed merchants." "Lightning attacks shatter the shoal's defences - a confusion of flashing scales." "The tiger sharks are not fast enough to keep up with this crowd." "But these new arrivals are about to show the lot of them how it's done..." "Bryde's whales... while sharks take a single fish in each attack, these monsters take a hundred kilos of fish with a single lunge." "From guano to huge ocean predators... it's one of the most fruitful food chains on the planet - and it underpins the whole shark battlefield." "Across the island there's another gathering." "It's in the main channel." "These are grey reef sharks - and they meet at this spot every day." "They've got to keep moving or they'll sink and drown, but they can 'rest' by hanging in the current." "As the tide moves in and out, they just go with the flow." "To our hungry female tiger, it's a tantalising sight... but grey reef sharks have numbers on their side..." "One spots the cruising tiger... and warns her to keep her distance." "The body language of the smaller shark is crystal clear." "By swimming in this strange, stiff manner - snout up, pectoral fins down - it signals that the tiger should back off." "And although it's just a quarter of the tiger's size, a grey reef shark could seriously damage her by slashing at her gills." "The stand-off is interrupted... and it could mean food." "It's a shoal of spawning parrot fish." "Every time they dart up to mate they produce a sound, and sounds travel further in water than in air - it's a dinner bell for sharks." "Reef sharks are sensitive to just this kind of low-frequency sound..." "Our tiger registers the racket too..." "And whitetips join the scramble." "A whitetip is first on the scene the parrotfish are in a 'spawning stupor' and slow to react..." "The whitetip catches one... but with a larger grey reef shark arriving, can it keep its catch?" "The grey reef shark has made off with the whitetip's prey, but it attracts too much attention and not just from other members of its own gang." "Our tiger shark's back and she's picked up the smell of sliced fish." "But with forty babies inside, she's just too slow." "The reef shark keeps its fish." "The pregnant female will have to draw upon her own fat reserves so her unborn pups can grow." "They're now six weeks from birth, but they'll need to develop some more before they're ready for the outside world." "Their mother heads again for deeper water." "For now, the islands and other prey are safe but even sharks have problems." "There are times when they must call a truce... moments when food is not the top priority." "Clinging to this whitetip's skin there are hundreds of tiny sea lice." "They suck its blood and damage its chain mail suit." "The whitetip can't get rid of them... but it knows a fish that can." "There are fish on the reef that eat such parasites - and they're just waiting for the chance to get to work." "This turtle drops into their cleaning station." "Each cleaner fish eats over a thousand parasites a day." "Eager clients are prepared to queue for treatment... some are more patient than others." "Without cleaner fish, the clientele could die of skin disease." "But luckily, they're open at the same address seven days a week, and all the locals know it." "Reef sharks are on their way... and cleaning station customers could be vulnerable..." "Hammerheads are heading there too." "But the sharks aren't hunting." "Sharks are also patrons of the cleaning station." "Up to twenty settle into their favourite seats and wait for service." "Like a formula one pit stop team, the shark cleaners race into action gills fins head, mouth and eyes - they all get a thorough inspection." "The cleaners do the inside too!" "They're so important to the sharks that they can go where other fish would fear to swim." "It's not only whitetips at the drive-through." "Up above, grey reef sharks join the queue." "They can't stop - they must keep moving to keep breathing - so their pit stop team swims along with them." "A hammerhead is next in line." "Fungus is playing havoc with its skin, and it rolls over to invite attention." "The cleaners pile in..." "For a short time, this is neutral ground on the shark battlefield." "The hammerheads are serviced and leave... but the tiger sharks are nowhere to be seen." "They're gathered in one particular part of the lagoon - as they've been doing for the past two weeks." "But for what?" "Each morning they arrive, just hang around a few hours, then leave again." "Scents in the water say they're in the right place, but they're too early and so far nothing's happening." "Today, though, could be the day." "It's some time now since our pregnant female last fed... and for her unborn pups, the lack of food is reaching crisis point again." "But here's the signal she's been waiting for... lt's just the sound of waves above - but what it says is that the wind is picking up." "And the sharks have learned that the wind can mean fresh food at the surface." "The light is blinding but a special pigment curtain in the shark's eyes enables them to adapt." "And here's what they've been looking for..." "A colony of albatrosses full of chicks about to learn to fly." "All they've been waiting for is wind." "And all the tiger sharks are waiting for is them." "This morning there's a stiff breeze... and the chicks are ready to set off." "One by one, they make their way to the water, where they attempt to take off." "...but every splash could mean a meal... our female moves in for the kill." "But the chicks are not the sitting ducks they seem... our shark's own bow wave sweeps them out of harm's way!" "Another reason for her failure is that just before attack, a protective membrane covers her eyes and she swims blind... or risk serious injury from this sharp bill." "She still has her electrical receptors as a guide... but in half air, half water, the grab is not precise." "Our pregnant mother can't afford to miss this opportunity." "Soon all the chicks will be gone." "With the breeding season coming to an end, this could be our tiger's last chance to feed at the island this year." "And back out in the open ocean, finding a meal will be even more difficult." "If she doesn't get enough food, neither will her babies." "Each one is now sixty centimetres long, packed tightly in the womb like sardines in a can." "Their mother has to eat - and eat well - if they are all to survive." "But, today, one last wave of chicks warms up for take-off." "It's late - they've missed the morning breeze, and as the wind drops, they flounder in the sea." "They seem oblivious of the danger and by now the sharks have learned new tricks." "They rush across the surface, so they don't make bow waves... and the chicks don't know what's hit them." "Our female has fed well." "Her growing babies can put on their final spurt." "With shark stomachs full, the last few albatrosses have a smooth start." "Soon our mother will give birth, but where is still a total mystery." "Even with all our technology and scientific knowledge we still don't know where in the ocean tiger sharks begin their lives." "Nobody has ever witnessed a tiger shark birth." "What we do know is that only two or three will survive their first few years at sea." "And if they do, in five years time they'll come back to join the hunt at the Shark Battlefield."