Grizzly Bear Transformation (Full Episode) | Built for the Kill | Nat Geo Animals

NARRATOR: This is a grizzly. 1000 pounds of muscle ... teeth ... and claw. This is a grizzly cub. One pound of blind, toothless fluff. It's no natural born killer. It has to learn how to hunt. Learn how to battle its fiercest foe. Learn to become... Built for the Kill. The North American wilderness. Home of the ultimate showdown. Grizzly bear. Wolf. Two top predators. Two deadly rivals. Wolf and bear are ancient enemies. The bear has size, strength and speed. The wolf has the power of numbers. It's a face off that began the moment the bear was born... The middle of winter. Storms rage. But all is quiet underground. A 400 pound female gives birth to one pound cub. Blind, toothless and utterly helpless. But he grows fast. Feeding on milk containing more fat than heavy whipping cream. In three months, he'll be ten times heavier. And it will be spring... The female is the first to emerge, after 6 months inside the den. But warm weather brings danger. Snow fields become unstable... Underground, the cubs would never know what hit them! This avalanche missed. There are many more dangers beyond the den. But the female is starving. Over winter - she lost 40% of her bodyweight. It's the cubs first day above ground. And survival lessons begin. The young male has only one teacher: mom. Following in her footsteps, he learns what's good to eat and where to find it. When he's not goofing around. Mom keeps her cubs close. Other bears are the biggest threat. An adult male just out of the den. Lean. Mean. And hungry. Weighing in at close to 1,000 pounds, he's nearly twice the size of the female. And armed with formidable weapons. Huge muscles on back and shoulders power immensely strong arms. Massive paws are tipped with lethal claws: 6 inch talons twice the size of polar bear and black bear. Grizzlies pack a helluva punch... When bears fight: blows break teeth Blind eyes. Shatter jaws... A single swipe once knocked a man's head clean off his shoulders. The grizzly's bite generates enough force to crush a bowling ball. Enormous muscles attached to the skull power the jaws. The teeth are strong enough to bite through a cast iron skillet And a baby bear. Big grizzlies are cub killers. just one defense. Adults are too big and heavy to haul themselves up trees. Cubs can. Faced with a feisty mom, he goes in search of an easier meal. Leaving the young male with a different problem... He was lucky. Few males reach adulthood uninjured. Falls, fights and famine take their toll. In some places, half of all cubs will never see their third birthday. It's a harsh land to bring up babies. The weather is fickle. The hunters ferocious... There's no love lost between the two top predators. Babies are innocent victims. Wolves kill cubs. But a mother bear is dangerous. A single blow can break a wolf's back The pack goes looking for easier prey. And so does the female. Wolves beware... The alpha female. Guarding the den with her pups. But eventually, she has to leave in search of water. Big mistake. The female is desperate for protein. One wolf against a hungry mother? It's no contest. The wolf has lost her family. The bear has found protein. But it's not enough. Once her cubs leave the den, mother must quadruple her milk production. Hunting animals is hard - picking plants is easy. In some places, plant material makes up 97% of a grizzly's diet. While his sisters mimic their mother - digging for roots.... the little male goes exploring. He's equal parts appetite and curiosity. At this age, he desperately needs his mother's protection... The young male will have to sharpen up, if he's to survive. He needs three years at his mother's side. Learning what to kill -how to catch it ... honing his senses. A young elk's best defense is to hide. But the bear follows her nose. She can sniff out prey a mile away. Her snout contains two highly sensitive chambers - 100 times larger than the human nose packed with over a billion receptor cells. Ten million nerve strands fire electrical signals straight to the brain. It's the cubs' first hunting lesson. The calf's only hope is to run! taste of blood. And valuable protein for their mother's milk supply. She's protector. Provider. And teacher. The young male will need all the help he can get, for it won't be long before he faces a pack of one of the continent's most powerful predators... Like all good parents, the female grizzly can't be too over protective. The cub's survival will depend on his curiosity and sense of adventure. Even running water is a hazard... Rivers swollen by melting snow are no problem for an adult. Grizzlies are excellent swimmers. But cubs need coaxing. The female grizzly is a patient teacher, but if they don't learn fast they'll go hungry.... Elk seek sanctuary in water. It's a great defense against hunting wolves. But not bears. If the mother was alone the deer would be dead. But her cubs are in danger! Do they drown? Or starve? What's a mother to do? There'll be other deer. And soon the river will be full of food. Millions of migrating salmon. But there's a problem Big bears love salmon And hate competition. In grizzly society size matters... The biggest get the best fishing spots... The fish are driven upstream to their spawning grounds. Rocks and boulders slow the salmon. Experienced anglers catch 100 pounds of fish a day. Essential protein for bears fattening up for winter. The female needs fish to feed her babies. But she must select her fishing ground carefully. Big bears are cub killers. The best fishing spots are taken. So she moves upstream. Surrounded by strangers the family's nervous. Cubs are as nourishing as fish and just as easy to catch. Mom moves to a better fishing rock. The cubs try to follow. Disaster. The sisters are safe. But the young male's swept into big bear territory! Mom won't give him up without a fight! Over the next three years, the young male will have many more near death experiences. But he'll survive. Until the day he leaves his mother's side, and enters the long sleep of winter alone.... The young male is now three years old. Alone in his den, he dozes. Ready to defend himself. Wolves hunt in winter. In spring, hunger will draw them together. Two top predators, facing off in the ultimate showdown. Hunger drives the young male out of his den and into a frozen wilderness. It's 6 months since he last ate. He's lost a quarter of his bodyweight. He needs food fast, so the young male follows his nose. The young male's survival will depend on the skills he learned Unfortunately, he may have been dozing through the lesson on ground squirrels. The rodents are fast. They vanish - only to pop out of another tunnel. The young male tries his luck at the coast. Low tide reveals a bounty. Clams - squirting water as they dig deeper. Not deep enough. He can eat a clam a minute. But the young bear's not the only one drawn to the coast in search of food.. Wolves kill bears, usually the young, the old, and the weak. And this bear is too close to the den. Time to go. The wolves can keep their seafood. The young male wants a bigger meal. It's hiding in the forest. Elk. It's time to put all his accumulated knowledge to work. He targets a baby! The mother runs in front showing her calf the best escape route. But the young male will not be distracted. His stamina's immense. His speed - terrifying. It's his first kill of the season. There will be many more. If he survives an encounter with his ultimate enemy.... Caribou. Migrating in herds 100,000 strong. For the young male, finding a herd is easy. Targeting an individual is hard. He's watching for weakness. The herd keeps well clear. So he tries Plan B: charge! A calf could be caught in the confusion. Time for Plan C: Ambush at the river crossing. The wolf pack has the same idea. Calves are swept from their mother's side. And swimming weakens the injured and old. Even males in their prime slip and break legs, or get them pinned between rocks. Falling behind can be fatal. The wolves find a target. An injured male: down but not defenseless. Caribou have the largest antlers in the world relative to body size. The wolves are wary. But the bear is hungry. Back downstream, the young male makes his move. The caribou's antlers are a potent defense. But they're not long enough. The young male struggles to make the killing bite. He's free of the antlers! And the deer is doomed... But the bear's battle has only just begun.... A lone wolf is not a problem. But she has back up. One bear. A pack of wolves. It's a grudge match three years in the making! The young male has the size. The wolves have the numbers! Round one to the wolves... But he's worked too hard to give up now... Wolf and bear. Two top predators with incredible stamina. The wolves are shrewd: they distract - and snatch. The bear has strength and lethal jaws and paws. Out of 19 recorded fights over a kill - bears won 10; wolves: 9. But this young male is driven by hunger. Finally, the male claims his reward. Incredible stamina... Astonishing strength... And sophisticated hunting skills ... combine to make the grizzly bear truly Built For The Kill.