HI, I'M BILL PULLMAN. WHEN I FIRST CAME TO MONTANA
40 YEARS AGO, I DIDN'T REALIZE
SOMETHING WAS MISSING FROM THIS PLACE
THAT SEEMS SO WILD. WOLVES WERE GONE, AND GRIZZLY BEARS WERE
CRITICALLY ENDANGERED. BUT ALL THAT WAS
ABOUT TO CHANGE. YELLOWSTONE NATIONAL PARK
BECAME THE STAGE FOR A GROUNDBREAKING COMEBACK-- THE RETURN OF THESE
ICONIC ANIMALS. BUT WHILE WE IMAGINE THEM
AS INVINCIBLE, YOU ARE ABOUT TO SEE THAT THEIR
LIVES ARE FULL OF HARDSHIP. A GRIZZLY MOM RAISING CUBS
HAS TO ALWAYS BE ON GUARD, AND A WOLF WITHOUT A PACK DOESN'T HAVE MUCH OF A CHANCE
TO SURVIVE. THIS IS THE STORY OF
THE RETURN OF THE PREDATORS. YELLOWSTONE. IT BEGAN WITH AN IDEA,
A BOLD EXPERIMENT: TO PROTECT THE WONDERS
OF THE NATURAL WORLD. BUT FOR NEARLY A CENTURY
A MIGHTY FORCE WAS MISSING. ICONS, HUNTED AND FEARED. FOR ALL ITS BEAUTY,
YELLOWSTONE WAS IN CHAOS. A LAND OUT OF BALANCE. UNTIL THE RETURN
OF THE PREDATORS. [ROARING] THE GRAY WOLF HAS RECLAIMED
ITS TERRITORY. GRIZZLIES ARE TAKING BACK
THE THRONE. IN THE STRUGGLE OF THE CHASE AND THE TIRELESS BATTLE
FOR SURVIVAL... LIFE FOR A HUNTER IS NEVER EASY. A LEGENDARY MOTHER
GUARDS HER LEGACY. AND A LONE WOLF SEARCHES
DESPERATELY TO FIND A PACK. [BARKING] [HOWLING] THIS IS YELLOWSTONE REBORN. THE DAWN OF A NEW ERA
FOR BOTH PREDATORS AND PREY. [GROWL] [THUNDER] [GROWLING] [BIRDS SQUAWKING] [CHIRPING] MOUNTAIN BLUEBIRDS HERALD
THE ARRIVAL OF SPRING IN YELLOWSTONE. BUT NOTHING ANNOUNCES THE SEASON LIKE A MIGHTY GRIZZLY
WAKING FROM HIBERNATION. ♪ HUNGER DRIVES HIM
DOWN TO THE VALLEY, GUIDED BY A FAMILIAR SCENT. HIS NOSE, SEVEN TIMES STRONGER
THAN A BLOODHOUND'S, BRINGS HIM STRAIGHT
TO THE SOURCE. A WINTER-KILL BISON CARCASS. [GRUNTS] A RICH SOURCE OF PROTEIN UNLOCKED BY FAST-MELTING
ICE AND SNOW. ♪ BUT IT'S ALSO ATTRACTED ANOTHER. A LONE WOLF. A CURIOUS ADOLESCENT
NAMED BLACKTAIL. LIKE MANY YOUNG MALES, HE'S LEFT
BEHIND THE SECURITY OF HIS PACK TO STRIKE OUT ON HIS OWN. BUT BLACKTAIL IS ALREADY
TREADING ON THIN ICE. ♪ IT'S A RARE ENCOUNTER: TWO TOP PREDATORS
GOING TOE-TO-TOE. THE OLD BOAR HOLDS HIS GROUND. POSITION IS EVERYTHING. BUT WHAT BLACKTAIL
LACKS IN EXPERIENCE, HE MAKES UP FOR WITH BRAVADO. HE TAUNTS THE BOAR
WITH A PLAYFUL BOW. HE'S HUNGRY, AND
HE'S TESTING THE LIMITS. A SINGLE SWIPE COULD KILL. ♪ [ROARING] BLACKTAIL COULD OUTRUN THE BEAR, BUT HE STAYS CLOSE,
DARING HIM TO KEEP UP. [ROARING] LURING HIM FARTHER AND FARTHER
FROM THE CARCASS. [ROAR] ♪ THE BOAR HAS HAD ENOUGH. BLACKTAIL IS PLAYING
A DANGEROUS GAME. BUT THIS TIME
HIS STRATEGY WORKED. THOUGH HE MAY NOT KEEP
THE PRIZE FOR LONG. [HOWLING] [BARKING] COYOTES. THREE OF THEM. SEEING THAT BLACKTAIL'S ALONE, THEY FORM AN ALLIANCE
AND MOVE IN. [GROWLING] WOLVES ARE USUALLY TOP DOG, BUT THE COYOTES COME AT HIM
FROM ALL SIDES. [GROWLING] HE'S NEVER FACED A GANG
LIKE THIS BEFORE. [YIPPING] ♪ [GROWL] RELENTLESS, ORGANIZED, THE COYOTES CHASE HIM OFF, AND SWIFTLY TAKE POSSESSION. BLACKTAIL WILL GO HUNGRY. [HOOVES RUMBLING] OUT HERE, A LONE WOLF
IS A VULNERABLE WOLF. EVERY MOMENT WITHOUT ALLIES,
WITHOUT TERRITORY, BLACKTAIL'S AT RISK. [GRUNTING] [BISON BELLOWS] LIFE ON HIS OWN
ISN'T JUST DIFFICULT; IT MAY BE IMPOSSIBLE. HE MUST FIND A PACK BEFORE IT'S TOO LATE. ♪ SPRING CRESTS
WITH A WAVE OF GREEN THAT RISES UP
FROM THE VALLEY FLOOR AND RUSHES ACROSS THE PLATEAU. YELLOWSTONE'S GREAT HERDS
ARE RETURNING TO ONE OF THE LAST OPEN RANGES
IN NORTH AMERICA. BISON, ELK AND PRONGHORN MIGRATE
INTO THE PARK BY THE THOUSANDS IN PURSUIT OF
LUSH, GREEN FORAGE. THESE HERDS ONCE BECAME
SO NUMEROUS, THEY OVERGRAZED
YELLOWSTONE'S RICH VALLEYS, LEAVING THEM DAMAGED
AND DEPLETED. BUT NOW, IN SPRING'S FERVOR, A RESURGENT FORCE WORKS
TO KEEP THE SYSTEM IN BALANCE: THE WOLF PACK. THIS IS THE WAPITI PACK. THE LARGEST IN YELLOWSTONE. A FAMILY IN ITS PRIME. 20 MEMBERS STRONG... AND STILL GROWING. [BARKING] THEY ROAM THE VAST INTERIOR
OF YELLOWSTONE, A TERRITORY OF 200 SQUARE MILES. PERFECT WOLF HABITAT. BUT UNTIL RECENTLY, GRAY WOLVES
WERE GONE FROM THIS LANDSCAPE. A CENTURY AGO, PREDATORS WERE
SEEN AS THE ENEMY OF PROGRESS. ELIMINATED FROM NEARLY ALL
OF THEIR FORMER RANGE. SCIENTISTS HAD NOT
YET DISCOVERED THAT AN ECOSYSTEM CANNOT THRIVE
WITHOUT BOTH PREY AND PREDATOR. IN 1926, PARK RANGERS SHOT
YELLOWSTONE'S LAST WOLF. NO ONE UNDERSTOOD
THE CONSEQUENCES. BUT 70 YEARS LATER,
IN THE WINTER OF 1995, TWO HORSE-DRAWN SLEIGHS
CARRIED 15 GRAY WOLVES CAPTURED IN CANADA AND RELEASED THEM IN
THE YELLOWSTONE BACKCOUNTRY. IT WAS THE BEGINNING OF ONE OF THE MOST AMBITIOUS
RESTORATION PROJECTS IN HISTORY. ♪ NO ONE KNEW IF
THE WOLVES WOULD STAY, IF THEY COULD THRIVE
IN AN UNFAMILIAR PLACE. OR WHAT THE LONG-TERM EFFECTS
OF THEIR PRESENCE WOULD BRING TO THE YELLOWSTONE ECOSYSTEM. BUT IT DIDN'T TAKE LONG FOR THE WOLVES TO MAKE
YELLOWSTONE THEIR HOME. [BARKING] THE REVIVAL OF THE HUNT RETURNED THE MOST PRIMARY
DYNAMIC TO YELLOWSTONE... A PREDATOR PURSUING ITS PREY. [BARKING] THANKS TO THE RETURN
OF THE WOLF, THE WORLD'S FIRST NATIONAL PARK
IS NOW RECOGNIZED AS ONE OF THE ONLY INTACT
ECOSYSTEMS OF ITS KIND. [HOWLING] TODAY, MORE THAN 100 DESCENDANTS
OF THIS ENDEAVOR ROAM YELLOWSTONE. THE THRIVING WOLF PACKS KEEP
THE GRAZING HERDS IN CHECK. BUT THEY'RE NOT THE ONLY FORCE
RESHAPING YELLOWSTONE. HIGH IN THE ALPINE, ANOTHER
TOP PREDATOR IS ON THE RISE AND BEGINNING A RITE OF SPRING. A BOAR GRIZZLY, RACING TOWARDS
THE OBJECT OF HIS DESIRE: A FEMALE. [GROWL] THE MARATHON OF GRIZZLY
COURTSHIP, RARELY WITNESSED, IS A TEST OF WILLS
AND ENDURANCE. THE RELUCTANT FEMALE CAN RUN IN
BURSTS UP TO 35 MILES PER HOUR. THE BOAR MUST KEEP PACE
OR RISK LOSING HER TO A RIVAL. [GRUNTS] SO FAR, SHE SEEMS UNIMPRESSED. THE PURSUIT COULD LAST FOR DAYS. [ROAR] FINALLY SHE SLOWS HER PACE
AND ALLOWS HIM CLOSE. [ROAR] BUT NOT TOO CLOSE. [ROARING] AFTER A LONG CHASE, THE FEMALE
TURNS AND GREETS HER SUITOR. HIS TRIAL IS OVER. A FLEETING MOMENT OF UNION
THAT MAY LIVE ON WITH THE NEXT GENERATION
OF YELLOWSTONE GRIZZLIES. IF ALL GOES WELL,
BY NEXT SPRING, SHE'LL HAVE CUBS AT HER SIDE. DOWN IN THE VALLEY, TWO OF THIS YEAR'S CUBS HAVE
JUST EMERGED FROM THEIR DEN. [CUB GROANS] A LEGENDARY MOTHER
LEADS THE WAY. HER NAME IS QUAD-MOM. THE MATRIARCH OF YELLOWSTONE. ONE OF THE MOST REVERED
GRIZZLY SOWS IN PARK HISTORY. IN SPRING 2010,
SHE EMERGED WITH FOUR CUBS, ONE OF ONLY A HANDFUL
OF QUADRUPLETS EVER OBSERVED IN YELLOWSTONE. QUAD-MOM EARNED HER NAME. HER FAME SPREAD, AND SO DID HER MANY OFFSPRING, WHO NOW RANGE THROUGH THE
GREATER YELLOWSTONE ECOSYSTEM. HER LEGACY HAS HELPED
BRING GRIZZLIES BACK FROM THE BRINK
OF EXTINCTION. 40 YEARS AGO,
THE YELLOWSTONE GRIZZLY WAS PLACED ON
THE ENDANGERED SPECIES LIST. AT THE TIME, FEWER THAN 150
BEARS REMAINED IN THE PARK, THEIR NUMBERS DECIMATED BY A CENTURY OF CONFLICT
WITH HUMANS. BUT, ONCE PROTECTED,
GRIZZLIES FLOURISHED. TODAY, MORE THAN 700 GRIZZLIES
CALL YELLOWSTONE HOME. QUAD-MOM IS NOW
MORE THAN 20 YEARS OLD. TIME IS NO LONGER ON HER SIDE. SHE'S AMONG THE OLDEST
WILD GRIZZLIES EVER TO BREED. THESE YOUNG CUBS COULD BE
THE LAST OF HER MANY LITTERS. AND THE RISING NUMBER OF BEARS
IN YELLOWSTONE HAS CREATED A NEW CHALLENGE: COMPETITION. A GASH RAKED ACROSS HER FOREHEAD
IS A SIGN OF RECENT TROUBLE. IT'S THE MARK OF
AN AGGRESSIVE BOAR. A TERRITORIAL MALE
WILL KILL CUBS TO BRING A SOW BACK INTO ESTRUS. SHE CAN'T LET HER GUARD DOWN. ♪ SHE CATCHES WIND OF SOMETHING... JUST OVER THE HORIZON. [GRUNTING] THE BOAR'S SCENT
HAS GIVEN HIM AWAY. TIME TO LEAVE... AND QUICKLY. ♪ ♪ [CUB CRIES] [THUNDER] [RAIN FALLING] ♪ BY LATE JUNE, ABUNDANT RAIN
AND MAXIMUM DAYLIGHT DRIVE AN EXPLOSION OF GROWTH. ♪ [THUNDER] ♪ ON CUE, YELLOWSTONE'S HERDS
ARE BRIMMING WITH NEW LIFE. ♪ ♪ BUT WHERE PREY ARE MANY,
PREDATORS ARE NEVER FAR. THIS IS THE MOLLIES PACK, CELEBRATED AS ONE OF THE FIRST
PACKS TO FORM AFTER THE WOLF REINTRODUCTION. FOR MORE THAN 20 YEARS
THEY'VE RULED THE LAMAR VALLEY, LIMITING THE ELK HERD
TO A HEALTHY SIZE. BUT THEIR REIGN IS
NO LONGER CERTAIN. THE MOLLIES HONED THEIR SKILLS
HUNTING ELK. BUT THIS TIME
THEY'VE SET THEIR SIGHTS ON SOMETHING MORE DIFFICULT. AS ELK BECOME LESS PLENTIFUL,
BISON FILL THE VOID. REVIVING THE BISON HUNT
MAY BE THE KEY TO THE MOLLIES'
CONTINUED SUCCESS. A WALL OF HORNS AND HOOVES
STANDS GUARD. INSTINCTIVELY, MOTHERS
SHIELD THEIR CALVES. AND WHEN DANGER THREATENS,
THE HERD CLOSES RANKS. [GROWLING] [BARK] THE PACK CREATES CONFUSION, TRYING TO SHAKE THE CALF
LOOSE FROM THE HERD, PROBING FOR ANY WEAKNESS. WOLVES ARE BUILT FOR STAMINA. [GRUNTS] THE CHASE IS ON. ♪ THE BISON HUNT IS A NEW TEST
FOR BOTH PREDATOR AND PREY. AN ANCIENT STRUGGLE MISSING FOR
NEARLY A CENTURY HAS RETURNED. AS THE MOLLIES PUSH
THE BISON UPHILL, A LONE WOLF APPEARS
OUT OF THE SAGE: BLACKTAIL. STILL ALONE, STILL HUNGRY, AND STILL DESPERATE. HE SNEAKS IN TO GRAB A SHARE
OF THE ELK CARCASS WHILE THE PACK'S DISTRACTED. IN THE MOLLIES' TERRITORY,
IT'S A DANGEROUS MOVE. AT ANY MOMENT, THE WOLF PACK
COULD RETURN TO DEFEND ITS KILL. ♪ THE INTERLOPER HAS BEEN SPOTTED. ♪ THE MOLLIES WON'T
TOLERATE BLACKTAIL STEALING FROM THEIR ELK KILL. THIS IS THEIR TURF. THE TRESPASSER MUST BE
HUNTED DOWN. IT'S AN AGGRESSIVE DISPLAY
THAT'S HARDLY EVER WITNESSED. ♪ [SNARLING, YELPING] [SPLASH] BLACKTAIL IS TRAPPED
IN THE CREEK. [BARKING] THE PACK CLOSES IN. [BARKING, HOWLING] [GROANS] [SQUAWKING] TATTERED, SOAKED TO THE BONE, BLACKTAIL IS LUCKY
TO ESCAPE ALIVE. [DRINKING] ♪ IF HE CAN'T FIND A PACK,
HIS LUCK WILL RUN OUT. ♪ THESE ARE THE TRIALS
OF A LONE WOLF. ALL HE CAN DO IS LICK HIS WOUNDS
AND STRUGGLE ON. THE RESURGENCE OF WOLVES
AND BEARS IN YELLOWSTONE SHIFTS THE DYNAMIC
NOT JUST FOR PREY, BUT ALSO FOR OTHER PREDATORS. [BISON GRUNTS] CHIEF AMONG THEM, THE COYOTE. WHEN WOLVES WERE GONE
AND BEARS FEW, THE COYOTE POPULATION
SKYROCKETED. NOW, THE BALANCE HAS CHANGED. WOLVES CHASE DOWN COYOTES
AT EVERY OPPORTUNITY. BEARS ARE EQUALLY MENACING. [ROAR] ONLY THREE YEARS AFTER
WOLF REINTRODUCTION, THE NUMBER OF COYOTES
DROPPED BY HALF. BUT THE GENIUS OF THE COYOTE
IS IN ITS ADAPTABILITY. WITH LARGER PREY CLAIMED
BY BIGGER PREDATORS, COYOTES SHIFT THEIR FOCUS
TO SMALLER QUARRY. TAKE AWAY ONE FOOD SOURCE,
AND ANOTHER POPS UP. A VOLE, A SMALL SOCIAL RODENT
WEIGHING LESS THAN TWO OUNCES. WITH SHARP HEARING
AND SWIFT REFLEXES, THE COYOTE MAKES QUICK WORK
OF THE COLONY. ♪ [SQUEAKING] ♪ [SQUEAKING] IT LOOKS EASY. BUT THERE'S A CATCH: SMALLER PREY MEANS
HE NEEDS MORE. ESPECIALLY BECAUSE
HE HAS OTHER MOUTHS TO FEED. ♪ [GROWLING] [YELPING] AS WOLVES AND BEARS
RECLAIM YELLOWSTONE, COYOTE NUMBERS MAY NEVER
RETURN TO THEIR PEAK. BUT OUTSIDE YELLOWSTONE,
IT'S ANOTHER STORY. UNLIKE LARGER CARNIVORES, COYOTES HAVE ADAPTED WELL
TO HUMAN HABITAT. THEY'RE DRAMATICALLY EXPANDING
FROM THEIR HISTORICAL RANGE, SPREADING TO THE FARTHEST
CORNERS OF NORTH AMERICA AND BEYOND. [GRUMBLING] BY AUGUST, QUAD-MOM'S CUBS ARE GAINING ALMOST
TWO POUNDS PER DAY, AND GROWING FRISKIER
BY THE MINUTE. [CUB GROANS] [CUB GROANS] KEEPING THEM FED AND OUT OF
TROUBLE IS A FULL-TIME JOB. [GROANING] BUT TAKING A BREAK TO ESCAPE THE
SUMMER HEAT IS AWFULLY TEMPTING. ♪ ♪ THE CUBS AREN'T SO SURE. THEY'D RATHER STAY ON THE RUN. BUT THEY'LL NEED ALL THE ENERGY
THEY CAN MUSTER, BECAUSE THEY'RE ABOUT TO EMBARK
ON AN EPIC JOURNEY. THE NURSING CUBS HAVE
A CONSTANT DEMAND FOR FOOD. QUAD-MOM KNOWS A SECRET SOURCE
OF CALORIES. BUT IT MEANS LEAVING BEHIND
THE LUSH VALLEY... [ROCKS CLATTERING] LEADING THE CUBS INTO
A COMPLETELY DIFFERENT WORLD. ♪ [SCREECH] ♪ ♪ ♪ ♪ ♪ SHE CLIMBS TO A REMOTE FACE
OF YELLOWSTONE FEW HAVE EVER LAID EYES ON. IT'S AN UNEXPECTED DESTINATION
FOR A LARGE CARNIVORE. BUT EACH AUGUST, A HIDDEN FEAST
LURES BEARS TO THE HIGH ALPINE. QUAD-MOM IS NOT ALONE. THE MOUNTAINS ARE CRAWLING
WITH GRIZZLIES. ♪ AT FIRST GLANCE,
IT'S A BARREN LANDSCAPE. BUT NESTLED AMONG THE ROCKS,
A SPLASH OF COLOR. ALPINE WILDFLOWERS. THEIR SWEET NECTAR ATTRACTS HUNDREDS OF THOUSANDS
OF ARMY CUTWORM MOTHS. THESE ARE WHAT THE BEARS
HAVE COME FOR. EACH AUGUST, THE MOTHS MIGRATE
IN SWARMS FROM THE GREAT PLAINS. THE FATTENED INSECTS BURROW DEEP
INTO CREVICES DURING THE DAY, HIDDEN AWAY FROM
INTENSE SUNLIGHT. UNTIL A HUNGRY INTRUDER
DISRUPTS THE PEACE. DURING THE FEAST, THE GRIZZLIES EACH GORGE
ON 40,000 MOTHS PER DAY, 20,000 CALORIES, THE RICHEST BOUNTY OF FAT AND
PROTEIN IN ALL OF YELLOWSTONE. QUAD-MOM HAS PERFECTLY
TIMED HER ARRIVAL TO TAKE ADVANTAGE OF
THIS BRIEF ABUNDANCE. SHE'LL CONSUME HALF HER ANNUAL
CALORIES IN ONLY 30 DAYS. A VITAL STOCKPILE FOR WINTER. EVEN THE CUBS HAVE CAUGHT ON, RELISHING THEIR FIRST MOTHS
IN THE ALPINE. ♪ IN YELLOWSTONE,
SURVIVAL HINGES UPON HEEDING NATURAL,
PREDICTABLE CYCLES. BUT IN RARE CASES,
THE FUNDAMENTAL RULES OF NATURE APPEAR TO TURN UPSIDE DOWN. AND DAY TURNS INTO NIGHT. ♪ THE MIDDAY SUN IS FADING. A SUDDEN CHILL GRIPS THE AIR. THE BUZZ OF INSECTS QUIETS, AND THE FEEDING FRENZY
COMES TO A HALT. ALL ACROSS YELLOWSTONE, DARKNESS DESCENDS. ♪ TRAVELING AT
1,800 MILES PER HOUR, THE MOON'S SHADOW
SLICES A NARROW PATH ACROSS NORTH AMERICA. ♪ A TOTAL SOLAR ECLIPSE
BLANKETS YELLOWSTONE IN A FLEETING AURA OF DARKNESS. ♪ ♪ ♪ THE COSMIC FIREWORKS
LAST ONLY TWO MINUTES. ♪ AS SUDDENLY AS THEY VANISHED,
LIGHT AND WARMTH RETURN. ♪ YELLOWSTONE WILL NOT EXPERIENCE
TOTALITY AGAIN FOR 235 YEARS. ♪ [ELK BUGLES] IN AUTUMN, ANOTHER CYCLE
OF CHANGE IS UNDER WAY. THE GREAT HERDS
REVERSE THEIR FLOW, LEAVING THE HIGH COUNTRY
IN DROVES. AND WITH GOOD REASON. WINTER COMES EARLY
TO YELLOWSTONE. ♪ SUMMER'S BOUNTY IS GONE. BY NOVEMBER,
FOOD BECOMES TOO SCARCE. QUAD-MOM HAS NO CHOICE
BUT TO HIBERNATE. SHE'S PREPARED WELL. SINCE SPRING, SHE'S GAINED
30% MORE BODY WEIGHT. FOR THE NEXT FIVE MONTHS, SHE AND THE CUBS WILL RELY
ON THIS STORED ENERGY. BUT IT MAY NOT BE ENOUGH. ONLY HALF OF ALL CUBS
REACH A SECOND SPRING. ♪ AS GRIZZLIES RETREAT
TO THE SAFETY OF THEIR DENS, ANOTHER PREDATOR RISES
TO THE CHALLENGE. [HOWLING] THIS IS THE SEASON OF THE WOLF. WHILE OTHERS BATTLE
THE ELEMENTS, WOLVES ARE IN THEIR PRIME. THEIR SUCCESS IS TIED TO THE
COLLECTIVE STRENGTH OF THE PACK. ♪ BLACKTAIL HAS BEATEN THE ODDS
TO SURVIVE THIS LONG, BUT WINTER'S WRATH COULD BE
FATAL FOR A LONE WOLF. IN THIS LEAN SEASON,
EVERY MEAL IS CRITICAL. AND HIDING AMONG THE WILLOWS IS WHAT LOOKS LIKE
A PERFECT OPPORTUNITY. A WOUNDED BULL ELK,
HALF-FROZEN AT THE WATER'S EDGE. A WOLF PACK WOULD GO
STRAIGHT FOR THE KILL. BUT ALONE, BLACKTAIL HAS ALMOST
NO CHANCE OF TAKING IT DOWN. ♪ HE MUST WAIT UNTIL
THE BULL GIVES OUT. ♪ BUT TIME IS NOT IN HIS FAVOR. FAR ACROSS THE VALLEY,
A LEGION IS GATHERING: THE WAPITI PACK. MORE THAN 20 WOLVES STRONG, THEY TRAVEL IN FORMATION,
SEARCHING FOR PREY. THEY FOLLOW THE RIVER,
UNHURRIED, UNTIL, IN UNISON,
THEY SPOT SOMETHING. [PANTING] THE WOUNDED ELK. BLACKTAIL HOLDS HIS GROUND
IN THE MEADOW. HE CAN'T AFFORD TO ABANDON
THIS CHANCE OF A MEAL. THE WAPITIS GATHER
IN THE TIMBER. THEY'RE STAGING FOR AN AMBUSH
JUST AS NIGHT IS FALLING. [HOWLING] BUT IN THE RUGGED TERRAIN
HIGH ABOVE THE VALLEY FLOOR, ANOTHER AMBUSH HAS
ALREADY TAKEN PLACE. A WHITE-TAILED DEER IS CAREFULLY
CACHED IN THE SNOW. THE VICTIM OF YELLOWSTONE'S
MOST ELUSIVE PREDATOR: THE MOUNTAIN LION. [PURRING] ♪ [PURRS] ♪ HER KITTEN FOLLOWS. ♪ THEY VISIT THE CACHE TOGETHER,
FEEDING ONLY AT NIGHT. [PURRING] UNDER A CLOAK OF DARKNESS, SHE AVOIDS DETECTION
BY OTHER PREDATORS. THE UNRIVALED STEALTH
OF MOUNTAIN LIONS ALLOWED A SMALL POPULATION
TO PERSIST EVEN AS WOLVES AND BEARS
DECLINED. ALONE ON TOP OF THE FOOD CHAIN, THE BIG CATS HAD
LITTLE COMPETITION. THE KITTEN IS ONLY
EIGHT WEEKS OLD; FAR TOO YOUNG TO ACCOMPANY
MOM ON HUNTS. BUT THROUGHOUT ITS FIRST YEAR, THE CUB WILL DEVELOP
THE TRADEMARK KILLING BITE THAT LIONS USE TO ATTACK PREY. AND THEY'LL BEGIN
TO HUNT TOGETHER. ♪ IN SECRET, MOM AND KITTEN
HAVE GOTTEN THEIR FILL. BUT AS DAYLIGHT APPROACHES, THEY CACHE THE DEER
AND RETRACE THEIR STEPS... BACK TO THEIR DEN. ♪ THE SUN RISES ON WHAT LITTLE
REMAINS OF THE OLD BULL ELK. THE WAPITIS' NIGHT AMBUSH
WAS A SUCCESS. 20 WOLVES FED ON THEIR PRIZE
AND VANISHED, LEAVING ONLY SCRAPS
FOR RAVENS AND COYOTES. BLACKTAIL IS NOWHERE TO BE SEEN. THE WAPITIS ARE
ALREADY MOVING ON. A PACK THIS SIZE NEVER RESTS. THEY MUST KILL AN ELK
EVERY TWO TO THREE DAYS. BUT THIS TIME, THEY'RE ON THE
TRAIL OF AN EVEN LARGER PRIZE. ♪ ON THE HEELS OF THE PACK,
A LONE FIGURE STRAGGLES BEHIND. BLACKTAIL. FOLLOWING THE WAPITIS
AS THEY MARCH ON TO A BISON HUNT. BY LATE WINTER, AS SNOW PILES
HIGHER IN YELLOWSTONE, GRAZERS BECOME LESS MOBILE;
MORE VULNERABLE. THEIR WEAKNESS IS
ANOTHER'S STRENGTH. FOR THE WAPITI PACK, THESE ARE THE CONDITIONS
IN WHICH THEY THRIVE. [HOWLING] THEIR ENERGY IS
AT AN ALL-TIME HIGH. THEY'RE FEEDING ON
THEIR BIGGEST KILL YET: AN ADULT BISON. IT'S A NEW ERA FOR BOTH
PREDATOR AND PREY. THE BALANCE OF POWER HAS SHIFTED
TO THE WOLF PACK. ONLY A FEW PACKS IN YELLOWSTONE
HAVE EVER ACHIEVED THE MYTHICAL STATUS
OF TRUE BISON HUNTERS. NOW, THE WAPITIS ARE AMONG THEM. AS THE ALPHAS FINISH THEIR TURN
AT THE CARCASS, A FAMILIAR FACE APPEARS: BLACKTAIL. ♪ HE MAKES HIS MOVE. [SQUAWKING] ♪ BUT BLACKTAIL HAS
NOTHING TO FEAR. HE'S ALREADY ONE OF THEM. HE'S JOINED THE RANKS
OF THE WAPITIS. ♪ IT'S A RARE CASE. A YOUNG OUTSIDER
HAS SECURED A PLACE WITHIN THE ESTABLISHED PACK. THEY'VE ACCEPTED HIM. AND THEY WILL BE HIS LIFELINE. BUT HE OFFERS
SOMETHING IN RETURN. NOW THAT THE WAPITIS HAVE
A TASTE FOR BISON, AN ADDITIONAL MEMBER INCREASES
THEIR CHANCES OF SUCCESS. IN BLACKTAIL, THE PACK HAS
GAINED A LOYAL FOOT SOLDIER WHO WILL HUNT AND DEFEND
AT ALL COSTS. AFTER THE TRIALS
HE'S FACED ALONE, HE'S FINALLY FOUND
A LARGE EXTENDED FAMILY: THE STRONGEST PACK
IN YELLOWSTONE. [HOWLING] BUT AS THE SEASONS TURN
AND SPRING BANISHES THE SNOW, EVERYTHING IS
ONCE AGAIN IN FLUX. SO BEGINS ANOTHER CYCLE
IN YELLOWSTONE. AND THE COMPETITION
HAS RETURNED. IT'S QUAD-MOM
WITH BOTH HER CUBS. THE FAMILY HAS SURVIVED
ITS FIRST WINTER. AND IT'S TIME TO MAKE UP
FOR SIX MONTHS WITHOUT FOOD. THIS TIME, THE YEAR-OLD CUBS
ARE READY TO HUNT. ♪ SPRING DELIVERS THEIR
FIRST OPPORTUNITY: NEWBORN ELK CALVES. [CALF YELPS] DURING PEAK CALVING, THE BEARS
WILL HUNT AROUND THE CLOCK. ELK CALVES ARE BORN SCENTLESS. ONLY ABLE TO RUN
FOR SHORT BURSTS, THEY STAY HIDDEN
DEEP IN THE SAGE. ♪ THE ONLY WAY TO FIND THEM
IS TO FLUSH THEM OUT. IT'S LIKE LOOKING FOR
A NEEDLE IN A HAYSTACK. BUT THIS IS A GAME
QUAD-MOM HAS PLAYED BEFORE. [CALF YELPS] ♪ [GROWLS] SENSING AN OPPORTUNITY,
A COYOTE JOINS THE HUNT. [BEAR GROWLS] HE'S ON TO SOMETHING. [GRUNTS] ♪ BUT IT'S ONLY A HARE;
MUCH TOO FAST. [GRUNTING] ♪ ♪ NOW, HE'S ON TARGET. [ROARING] [BUGLING] [CALF SQUEALING] BUT THE CALF ISN'T GOING DOWN
WITHOUT A FIGHT. [BUGLING] ALERTED BY THE STRUGGLE,
QUAD-MOM JOINS THE CHASE. ♪ [CALF SQUEALING] [YELP] [BUGLING] THE COW ELK RUSHES
TO HER CALF'S DEFENSE. [SQUEALING] ♪ BUT THERE'S NOTHING SHE CAN DO. ♪ WITH THEIR MOTHER'S GUIDANCE, THE CUBS HAVE LEARNED
THE WAY OF THE PREDATOR. THEY WILL NOW PLAY A VITAL ROLE
IN SHAPING YELLOWSTONE. IN THE SPAN OF
A SINGLE LIFETIME, QUAD-MOM HAS PRESIDED OVER
A REMARKABLE TRANSFORMATION. THE RESTORATION OF
AN ANCIENT BALANCE. THE RETURN OF YELLOWSTONE'S
WILD HEART. A PLACE WHERE THE STORY
OF PREDATORS LIVES ON. BUT BEYOND THESE BORDERS,
A NEW FRONTIER BECKONS. WOLVES AND GRIZZLIES
ARE STILL GONE FROM MOST OF THEIR
HISTORIC RANGE. BUT GIVEN FREEDOM TO ROAM, THEIR LEGACY WILL
CONTINUE TO GROW, FROM THE PLACE WHERE
IT ALL BEGAN: YELLOWSTONE, THE WORLD'S
FIRST NATIONAL PARK. IT'S RARE TO HAVE SUCH
A CONSERVATION SUCCESS STORY, AND IT'S ANOTHER REASON
TO CELEBRATE YELLOWSTONE. BUT WHILE WOLVES AND BEARS
HAVE BECOME ICONIC SYMBOLS OF THIS PLACE, THERE ARE SO MANY OTHER ANIMALS THAT MAKE YELLOWSTONE
EXCEPTIONAL. THE PARK IS HOME TO MORE THAN
150 SPECIES OF BIRDS. THE NEXT "EPIC YELLOWSTONE"
FOLLOWS THEIR STORIES, SHOWING THE PARK FROM
AN ENTIRELY NEW PERSPECTIVE.
