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

0:02 NARRATOR: This is a grizzly.

0:05 1000 pounds of muscle...

0:08 teeth...

0:09 and claw.

0:10 This is a grizzly cub.

0:13 One pound of blind, toothless fluff.

0:18 It's no natural born killer.

0:21 It has to learn how to hunt.

0:25 Learn how to battle its fiercest foe.

0:30 Learn to become...

0:33 Built for the Kill.

0:50 The North American wilderness.

0:55 Home of the ultimate showdown.

1:07 Grizzly bear.

1:14 Wolf.

1:17 Two top predators.

1:27 Two deadly rivals.

1:54 Wolf and bear are ancient enemies.

2:13 The bear has size, strength and speed.

2:25 The wolf has the power of numbers.

2:31 It's a face off that began the moment the bear was born...

2:51 The middle of winter.

2:54 Storms rage.

2:58 But all is quiet underground.

3:04 A 400 pound female gives birth to one pound cub.

3:16 Blind, toothless and utterly helpless.

3:22 But he grows fast.

3:26 Feeding on milk containing more fat than heavy whipping cream.

3:37 In three months, he'll be ten times heavier.

3:43 And it will be spring...

3:58 The female is the first to emerge, after 6 months inside the den.

4:06 But warm weather brings danger.

4:11 Snow fields become unstable...

4:35 Underground, the cubs would never know what hit them!

4:47 This avalanche missed.

4:56 There are many more dangers beyond the den.

5:00 But the female is starving.

5:03 Over winter- she lost 40% of her bodyweight.

5:19 It's the cubs first day above ground.

5:23 And survival lessons begin.

5:36 The young male has only one teacher: mom.

5:41 Following in her footsteps, he learns what's good to eat and where to find it.

5:48 When he's not goofing around.

6:18 Mom keeps her cubs close.

6:24 Other bears are the biggest threat.

6:31 An adult male just out of the den.

6:39 Lean.

6:40 Mean.

6:41 And hungry.

6:45 Weighing in at close to 1,000 pounds, he's nearly twice the size of the female.

6:52 And armed with formidable weapons.

6:59 Huge muscles on back and shoulders power immensely strong arms.

7:07 Massive paws are tipped with lethal claws:

7:14 6 inch talons twice the size of polar bear and black bear.

7:21 Grizzlies pack a helluva punch...

7:25 When bears fight: blows break teeth Blind eyes.

7:33 Shatter jaws...

7:54 A single swipe once knocked a man's head clean off his shoulders.

8:00 The grizzly's bite generates enough force to crush a bowling ball.

8:07 Enormous muscles attached to the skull power the jaws.

8:13 The teeth are strong enough to bite through a cast iron skillet And a baby bear.

8:24 Big grizzlies are cub killers.

8:33 The young male has just one defense.

8:39 Adults are too big and heavy to haul themselves up trees.

8:44 Cubs can.

8:56 Faced with a feisty mom, he goes in search of an easier meal.

9:03 Leaving the young male with a different problem...

9:19 He was lucky.

9:23 Few males reach adulthood uninjured.

9:30 Falls, fights and famine take their toll.

9:37 In some places, half of all cubs will never see their third birthday.

9:53 It's a harsh land to bring up babies.

10:13 The weather is fickle.

10:17 The hunters ferocious...

10:54 There's no love lost between the two top predators.

11:02 Babies are innocent victims.

11:11 Wolves kill cubs.

11:21 But a mother bear is dangerous.

11:26 A single blow can break a wolf's back The pack goes looking for easier prey.

11:58 And so does the female.

12:01 Wolves beware...

12:14 The alpha female.

12:18 Guarding the den with her pups.

12:29 But eventually, she has to leave in search of water.

12:37 Big mistake.

12:44 The female is desperate for protein.

13:15 One wolf against a hungry mother?

13:21 It's no contest.

13:39 The wolf has lost her family.

13:42 The bear has found protein.

13:44 But it's not enough.

13:47 Once her cubs leave the den, mother must quadruple her milk production.

13:54 Hunting animals is hard- picking plants is easy.

14:07 In some places, plant material makes up 97% of a grizzly's diet.

14:15 While his sisters mimic their mother- digging for roots....

14:21 the little male goes exploring.

14:30 He's equal parts appetite and curiosity.

14:50 At this age, he desperately needs his mother's protection...

16:05 The young male will have to sharpen up, if he's to survive.

16:16 He needs three years at his mother's side.

16:20 Learning what to kill -how to catch it...

16:24 honing his senses.

16:27 A young elk's best defense is to hide.

16:31 But the bear follows her nose.

16:35 She can sniff out prey a mile away.

16:39 Her snout contains two highly sensitive chambers- 100 times larger

16:44 than the human nose packed with over a billion receptor cells.

16:50 Ten million nerve strands fire electrical signals straight to the brain.

17:02 It's the cubs' first hunting lesson.

17:17 The calf's only hope is to run!

18:14 It's the cubs' first taste of blood.

18:18 And valuable protein for their mother's milk supply.

18:49 She's protector.

18:50 Provider.

18:51 And teacher.

18:57 The young male will need all the help he can get,

19:00 for it won't be long before he faces

19:01 a pack of one of the continent's most powerful predators...

19:18 Like all good parents, the female grizzly can't be too over protective.

19:24 The cub's survival will depend on his curiosity and sense of adventure.

19:33 Even running water is a hazard...

19:39 Rivers swollen by melting snow are no problem for an adult.

19:48 Grizzlies are excellent swimmers.

19:52 But cubs need coaxing.

20:43 The female grizzly is a patient teacher,

20:46 but if they don't learn fast they'll go hungry....

20:53 Elk seek sanctuary in water.

20:56 It's a great defense against hunting wolves.

21:05 But not bears.

21:51 If the mother was alone the deer would be dead.

22:01 But her cubs are in danger!

22:10 Do they drown?

22:11 Or starve?

22:23 What's a mother to do?

22:30 There'll be other deer.

22:35 And soon the river will be full of food.

22:45 Millions of migrating salmon.

22:51 But there's a problem Big bears love salmon And hate competition.

23:08 In grizzly society size matters...

23:24 The biggest get the best fishing spots...

23:35 The fish are driven upstream to their spawning grounds.

23:42 Rocks and boulders slow the salmon.

23:57 Experienced anglers catch 100 pounds of fish a day.

24:03 Essential protein for bears fattening up for winter.

24:10 The female needs fish to feed her babies.

24:23 But she must select her fishing ground carefully.

24:28 Big bears are cub killers.

24:38 The best fishing spots are taken.

24:40 So she moves upstream.

24:49 Surrounded by strangers the family's nervous.

24:54 Cubs are as nourishing as fish and just as easy to catch.

25:06 Mom moves to a better fishing rock.

25:19 The cubs try to follow.

25:24 Disaster.

25:34 The sisters are safe.

25:43 But the young male's swept into big bear territory!

25:54 Mom won't give him up without a fight!

26:21 Over the next three years,

26:22 the young male will have many more near death experiences.

26:31 But he'll survive.

26:36 Until the day he leaves his mother's side,

26:40 and enters the long sleep of winter alone....

27:13 The young male is now three years old.

27:21 Alone in his den, he dozes.

27:24 Ready to defend himself.

27:28 Wolves hunt in winter.

27:35 In spring, hunger will draw them together.

27:39 Two top predators, facing off in the ultimate showdown.

28:06 Hunger drives the young male out of his den and into a frozen wilderness.

28:17 It's 6 months since he last ate.

28:23 He's lost a quarter of his bodyweight.

28:26 He needs food fast, so the young male follows his nose.

28:41 The young male's survival will depend

28:43 on the skills he learned at his mother's side.

28:50 Unfortunately, he may have been dozing through the lesson on ground squirrels.

29:01 The rodents are fast.

29:04 They vanish- only to pop out of another tunnel.

29:47 The young male tries his luck at the coast.

29:53 Low tide reveals a bounty.

30:08 Clams- squirting water as they dig deeper.

30:14 Not deep enough.

30:19 He can eat a clam a minute.

30:25 But the young bear's not the only one drawn to the coast in search of food..

31:05 Wolves kill bears, usually the young, the old, and the weak.

31:21 And this bear is too close to the den.

31:28 Time to go.

31:39 The wolves can keep their seafood.

31:51 The young male wants a bigger meal.

31:56 It's hiding in the forest.

32:14 Elk.

32:38 It's time to put all his accumulated knowledge to work.

32:46 He targets a baby!

32:51 The mother runs in front showing her calf the best escape route.

33:01 But the young male will not be distracted.

33:21 His stamina's immense.

33:27 His speed- terrifying.

33:41 It's his first kill of the season.

33:45 There will be many more.

33:47 If he survives an encounter with his ultimate enemy....

34:15 Caribou.

34:18 Migrating in herds 100,000 strong.

34:49 For the young male, finding a herd is easy.

34:57 Targeting an individual is hard.

35:36 He's watching for weakness.

35:45 The herd keeps well clear.

35:49 So he tries Plan B: charge!

35:57 A calf could be caught in the confusion.

36:03 Time for Plan C: Ambush at the river crossing.

36:16 The wolf pack has the same idea.

36:26 Calves are swept from their mother's side.

36:29 And swimming weakens the injured and old.

36:44 Even males in their prime slip and break legs, or get them pinned between rocks.

36:58 Falling behind can be fatal.

37:14 The wolves find a target.

37:18 An injured male: down but not defenseless.

37:26 Caribou have the largest antlers in the world relative to body size.

37:35 The wolves are wary.

37:38 But the bear is hungry.

37:42 Back downstream, the young male makes his move.

38:26 The caribou's antlers are a potent defense.

38:41 But they're not long enough.

39:02 The young male struggles to make the killing bite.

39:08 He's free of the antlers!

39:12 And the deer is doomed...

39:47 But the bear's battle has only just begun....

40:41 A lone wolf is not a problem.

40:46 But she has back up.

40:59 One bear.

41:01 A pack of wolves.

41:03 It's a grudge match three years in the making!

41:50 The young male has the size.

41:58 The wolves have the numbers!

42:12 Round one to the wolves...

42:18 But he's worked too hard to give up now...

42:30 Wolf and bear.

42:41 Two top predators with incredible stamina.

42:49 The wolves are shrewd: they distract- and snatch.

42:56 The bear has strength and lethal jaws and paws.

43:31 Out of 19 recorded fights over a kill- bears won 10; wolves: 9.

43:40 But this young male is driven by hunger.

44:31 Finally, the male claims his reward.

44:45 Incredible stamina...

44:50 Astonishing strength...

44:57 And sophisticated hunting skills...

45:00 combine to make the grizzly bear truly Built For The Kill.