SANJAYAN, VOICE-OVER: IN THE BAKING HEAT OF THE AFRICAN SAVANNA... AS RIVERS DRY UP... WILDLIFE FLOCKS TO THE WATERHOLE.

WE'VE NEVER FULLY UNDERSTOOD HOW A SINGLE WATER SOURCE CAN SUPPORT SO MANY COMPETING SPECIES... UNTIL NOW.

THIS WATERHOLE HERE, IT'S HUMAN MADE.

WE'VE TEAMED UP WITH SOME OF THE WORLD'S BEST SCIENTISTS AND CONSERVATIONISTS TO BRING A WATER SOURCE TO THIS REALLY HARSH, DRY PART OF AFRICA.

SANJAYAN, VOICE-OVER: WE'RE WORKING WITH THE RESERVE TO CREATE THE WORLD'S FIRST WATERHOLE WITH A BUILT-IN CAMERA SYSTEM.

THIS HAS NEVER BEEN DONE BEFORE, AND WE HAVE NO IDEA WHAT'S GOING TO HAPPEN, BUT THESE CAMERAS ARE ALWAYS ON AND THEY'RE READY TO CAPTURE THE ACTION.

SANJAYAN, VOICE-OVER: IN THE DRY SEASON... WE SAW A WILD COMMUNITY SPRING UP AROUND THIS NEW OASIS.

WOW.

[WHISPERING] IT'S LIKE MY HEART IS RACING RIGHT NOW.

SANJAYAN, VOICE-OVER: BUT WHEN A HUGE PREDATOR TURNED UP, EVERYTHING CHANGED.

MAN: OOH, LOOK AT THAT!

HA HA!

WOW!

THAT IS A BEAUTIFUL, BIG MALE LION.

SANJAYAN, VOICE-OVER: NOW IT'S THE HOTTEST TIME OF THE YEAR AND THINGS ARE GOING TO GET TOUGHER AS TEMPERATURES SOAR BEYOND 100 DEGREES...

TURNING THE WATERHOLE INTO A LIFELINE FOR THE RESERVE'S MOST VULNERABLE.

SANJAYAN: THAT'S AMAZING TO SEE AN ELEPHANT WITH HALF HIS TRUNK GONE.

SANJAYAN, VOICE-OVER: AND THIS PRECIOUS WATER SOURCE TURNS INTO A TARGET FOR A NEW PREDATOR.

[HYENAS LAUGHING] WILL A HYENA CLAN MUSCLE THE LOCAL LION PRIDE OUT OF THE AREA?

HYENAS WILL KILL LION CUBS ANY CHANCE THEY GET.

SANJAYAN, VOICE-OVER: THIS IS THE STORY OF LIFE... AND DEATH AT THE WATERHOLE.

SANJAYAN, VOICE-OVER: OUR WATERHOLE IS LOCATED ON THE MWIBA WILDLIFE RESERVE, PART OF THE SERENGETI ECOSYSTEM IN NORTHERN TANZANIA.

IT'S AN AREA SPANNING OVER 200 SQUARE MILES... A SANCTUARY FOR SOME OF AFRICA'S MOST ICONIC WILDLIFE.

THE LONG DRY SEASON IS COMING TO AN END... AND WE'RE BACK AT THE HOTTEST TIME OF THE YEAR.

FOR 8 HOURS A DAY, TEMPERATURES REACH A BLISTERING 100 DEGREES.

THE LANDSCAPE IS BEING SCORCHED BY THE SUN... AND ONE OF THE MAJOR SOURCES OF FOOD FOR HERBIVORES, ACACIA TREES, ARE ALMOST BARE.

OUR WATERHOLE COULD BE MORE IMPORTANT THAN EVER.

I CAN FEEL THE HEAT.

THIS IS THE HOTTEST TIME OF YEAR.

THE RAINS HAVEN'T BROKEN YET, THEY'RE JUST BUILDING, AND EVERY DAY JUST FEELS HEAVY AND HUMID.

IT'S GOING TO BE REALLY INTERESTING TO SEE HOW THESE COMMUNITIES OF ANIMALS THAT WE'VE GOT TO KNOW SO WELL, HOW THEY DEAL WITH THIS NEW CHALLENGE-- THE CHALLENGE OF HEAT.

SANJAYAN, VOICE-OVER: WITH NEARBY NATURAL WATER SOURCES DRIED UP AND WITH 5 MONTHS OF VERY LITTLE RAIN, OUR WATERHOLE IS NOW SERVICING A HUGE AREA.

THERE'S HARDLY ANY SHADE, SO JUST GETTING HERE CAN BE EXHAUSTING.

BUT WHEN WATER IS SO SCARCE...

IT'S A JOURNEY ANIMALS HAVE TO MAKE.

AND THINGS ARE ABOUT TO GET EVEN MORE DANGEROUS.

A SPOTTED HYENA.

SANJAYAN: I'VE HEARD SOMEONE CALL HYENAS THE "WOLVES" OF THE SERENGETI.

SANJAYAN, VOICE-OVER: BUT WHY IS THIS NOCTURNAL ANIMAL SHOWING UP AT OUR WATERHOLE IN BROAD DAYLIGHT?

LOOK AT THE BELLY ON THAT HYENA.

CLEARLY JUST EATEN.

I MEAN, REALLY EXTENDED BELLY.

THEY CAN PUT AWAY SO MUCH FOOD, EAT IT SO QUICKLY.

SANJAYAN, VOICE-OVER: THE HEAT AND HUMIDITY HAVE EVEN STARTED TO AFFECT ME.

[COUGHS] I'M LOSING MY VOICE.

SANJAYAN, VOICE-OVER: I'M ALSO SPEECHLESS THAT THIS LONE HYENA IS SO BRAZEN.

IT'S CLEARLY MADE A KILL NEARBY... AND IT'S POSSIBLY PICKING OFF DRINKERS AS THEY COME IN TO THE WATERHOLE.

SANJAYAN: I WOULDN'T BE SURPRISED IF HYENAS DO MOST OF THE KILLING IN THIS ENVIRONMENT, AND PARTICULARLY BRINGING DOWN VERY BIG ANIMALS LIKE BUFFALO WHERE YOU NEED, YOU KNOW, 20, 30 HYENAS TO BE ABLE TO PULL DOWN AN ANIMAL THAT'S CLOSE TO 1,000 POUNDS.

SANJAYAN, VOICE-OVER: THE SPOTTED HYENA GETS A BAD RAP AS A SCAVENGER, BUT THEY ARE ACTUALLY AFRICA'S MOST SUCCESSFUL HUNTERS.

OH, JUST LYING DOWN.

FROM A DISTANCE, YOU KNOW AT A WATERHOLE LIKE THIS MAYBE OTHER ANIMALS DON'T SEE IT.

SANJAYAN, VOICE-OVER: BUT FOR THE ONES THAT DO SEE IT, THE PRESENCE OF THIS PREDATOR IS LIKELY TO MAKE THEM REALLY NERVOUS ABOUT COMING TO THIS WATERHOLE.

IT'S UNEXPECTED TO ADD A NEW APEX PREDATOR TO OUR SPECIES LIST SO SOON INTO THE HOTTEST TIME OF YEAR.

WHEN IT'S AT THIS WATERHOLE, IT FEELS SPECIAL BECAUSE IT'S THE FIRST TIME.

I THINK THAT'S WHAT MAKES THIS SO EXCITING.

YOU JUST HAVE NO IDEA WHAT'S GONNA SHOW UP, AND EVERY NEW ARRIVAL IS CELEBRATED, REALLY CELEBRATED AS A NEW ARRIVAL, AS A NEW DISCOVERY.

SANJAYAN, VOICE-OVER: IT'S ALSO THE BEGINNINGS OF A MYSTERY.

IT'S UNLIKELY THAT THIS HYENA IS HUNTING ALONE, SO WHERE'S HIS CLAN, AND EXACTLY HOW MANY OF THEM ARE OUT THERE?

THE ARRIVAL OF A HYENA MUST HAVE AN IMPACT ON THE LOCAL LION PRIDE.

LAST TIME, CAMERAMAN BOB POOLE DISCOVERED A LIONESS CALLED LERIAH HUNTING AROUND THE WATERHOLE DESPERATE TO FEED HER CUBS.

[WHISPERING] WOW, WHAT A POWERFUL ANIMAL.

SANJAYAN, VOICE-OVER: SHE SEEMED LIKE A FIRM FIXTURE IN OUR AREA, BUT SINCE WE'VE BEEN BACK, WE HAVEN'T SEEN HER NOR HER CUBS.

BOB HEADS 3 MILES OUT OF CAMP TO CHECK CAMERA TRAPS WE'VE PLACED AROUND A CARCASS NEAR LERIAH'S DEN.

I'M ANXIOUS TO SEE WHAT WE'VE GOT HERE.

POOLE: THERE'S THE MOTHER RIGHT THERE.

SHE CAME IN LOOKING QUITE DEFENSIVE.

SANJAYAN, VOICE-OVER: IT'S A RELIEF TO SEE LERIAH, BUT SOMETHING ISN'T QUITE RIGHT.

POOLE: WOW.

[HYENAS LAUGHING] HYENAS.

SANJAYAN, VOICE-OVER: A WHOLE PACK OF HYENAS HAVE DESCENDED ON THE CARCASS.

WHY, 1, 2, 3, 4, 5, 6, 7, 8.

DEFINITELY LOOKING BACK TOWARDS WHERE THE LIONESS IS.

I GUESS THE LIONESS IS PROBABLY OUT OF VISION JUST-- JUST BEHIND THE CAMERA THERE, SO A LOT OF CONFRONTATION GOING ON.

NOW, WHEN YOU GET A PACK OF HYENAS AND THEY'RE COMING AT YOU FROM ALL SIDES, ONE FEMALE CAN'T BEGIN TO DEFEND A CARCASS LIKE THIS, ESPECIALLY WHEN SHE HAS LITTLE CUBS THAT SHE'S GOT TO PROTECT, AND THAT WOULD BE HER NUMBER-ONE OBJECTIVE, WOULD BE TO GET THOSE CUBS OUT OF THERE SAFELY.

SANJAYAN, VOICE-OVER: BOB CAN'T QUITE SEE WHERE LERIAH GOES OR IF SHE EVEN MANAGES TO GET HER CUBS OUT OF DANGER.

HYENAS WILL KILL LION CUBS ANY CHANCE THEY GET.

SANJAYAN, VOICE-OVER: IT'S A WORRYING TURN OF EVENTS.

BOB WILL KEEP SEARCHING TO FIND OUT IF LERIAH AND HER CUBS SURVIVED.

DAYTIME TEMPERATURES ARE NOW SO UNBEARABLY HOT.

THE COOLER NIGHTS ARE DRAWING IN MORE NEW SPECIES, INCLUDING ONE AFRICAN GIANT THAT YOU TYPICALLY SEE IN A WATERHOLE RATHER THAN OUT OF IT.

NO!

LOOK AT THE HIPPO.

HOLY MOSES.

SANJAYAN, VOICE-OVER: GUIDE NUHU MHAPPA IS WITH ME TO LOOK AT THE FOOTAGE OF OUR VERY FIRST HIPPO AT THE WATERHOLE.

THAT'S UNBELIEVABLE, HUH?

WELL, I-- I WASN'T EXPECTING SOMETHING LIKE THIS TO HAPPEN.

SANJAYAN: IT DOESN'T SEEM LIKE HE'S COMING TO THIS POND.

HE'S JUST PASSING RIGHT THROUGH IT.

YEAH, YEAH, YEAH.

YEAH, HE'S NOT INTERESTED AT ALL.

HE MIGHT HAVE ALREADY KNOWN THAT THIS AREA IS NOT DEEP ENOUGH FOR HIM TO BE HERE.

SANJAYAN: I MEAN, THESE HIPPOS GO A LONG WAY FROM WATER TO FEED, RIGHT.

THEY GO OUT ONTO GRASSLANDS AND GRAZE.

YES, YES, SO-- AND THEY CAN GO MANY MILES FROM--BECAUSE WHENEVER YOU SEE HIPPOS, YOU SEE THEM IN THE WATER, SO YOU THINK THEY'RE EATING AQUATIC VEGETATION, BUT THEY'RE NOT.

THEY'RE ACTUALLY COMING ON LAND AT NIGHT AND GOING VAST DISTANCES.

MHAPPA: VAST DISTANCES.

SANJAYAN, VOICE-OVER: EACH NIGHT, A HUNGRY HIPPO CAN EAT OVER 65 POUNDS OF GRASS.

IS THAT SOMETHING THERE?

I DON'T KNOW.

IS IT A ROCK?

SANJAYAN, VOICE-OVER: AND HE ISN'T THE ONLY ANIMAL LOOKING FOR A MIDNIGHT MEAL.

THAT'S AN OWL.

IT'S CALLED A VERREAUX'S EAGLE-OWL.

SANJAYAN, VOICE-OVER: THE VERREAUX'S EAGLE-OWL IS A HIGHLY OPPORTUNISTIC PREDATOR.

IT'S EQUIPPED WITH POWERFUL TALONS, EAR TUFTS, AND CRAZY EYELIDS.

IT'S THE BIGGEST OWL THAT WE'VE GOT IN THE AREA.

IT'S GOT PINK EYELIDS.

LIKE SOMEONE HAS BEEN WORKING ON THEM, ON THEIR EYELASHES.

MHAPPA: LOOK AT THAT.

THAT'S BEAUTIFUL.

SANJAYAN: THAT'S INCREDIBLE.

THAT'S REALLY AMAZING.

I MEAN, WHAT AN UNBELIEVABLE LIKE TABLEAU OF WILDLIFE AND CRAZINESS, YOU KNOW, HIPPO GOES WALKING THROUGH, THEN A BUFFALO, AND THEN THE OWL TAKES OFF.

I MEAN, YOU'RE LIKE... THAT'S THE MAGIC OF THE WATERING HOLE.

SANJAYAN, VOICE-OVER: WE BUILT A WATERHOLE WITH NO IDEA IF ANIMALS WOULD EVEN SHOW UP.

BUT IN JUST A FEW MONTHS, IT'S BECOME A HOTSPOT OF THE AFRICAN SAVANNA.

IN THE DRY SEASON, PREY ANIMALS WERE THE MOST FREQUENT VISITORS, BUT NOW, IN THIS HOTTEST TIME OF YEAR, MORE AND MORE PREDATORS ARE COMING TO THE WATERHOLE.

SERVALS ARE MID-SIZED SAVANNA CATS.

THEY CAN LEAP UP TO 10 FEET IN THE AIR TO CATCH BIRDS MID-FLIGHT.

THE AFRICAN WILDCAT USES ITS ACUTE HEARING TO PRECISELY LOCATE PREY AROUND WATER POINTS.

SPOTTED GENETS USE THEIR RETRACTABLE CLAWS TO HUNT IN TREES AND ALSO DOWN ON THE GROUND.

THE WATERHOLE HAS NOW BECOME A REGULAR FEATURE IN THE LANDSCAPE.

PREY SUCH AS RATS AND HARES MAKE FREQUENT VISITS DURING THE NIGHT, GIVING THESE SMALLER PREDATORS OPPORTUNITIES TO HUNT.

WITH MORE PREDATORS STOPPING BY THE WATERHOLE AT NIGHT, YOU'D THINK EVERY OTHER ANIMAL WOULD VISIT FOR A DRINK DURING THE DAY, BUT THAT'S SIMPLY NOT THE CASE.

YOU KNOW, NOW IN THE HOTTEST TIME OF THE YEAR, ONE OF THE THINGS THAT WE'RE NOTICING LOOKING AT THE DATA IS THAT A LOT OF THE ANIMALS THAT WOULD COME PREFERENTIALLY IN THE MIDDLE PART OF THE DAY, IN THE SORT OF SUNNIEST, HOTTEST PART OF THE DAY--THE ZEBRAS, IMPALAS, WARTHOGS-- THAT WERE BASICALLY TRYING TO AVOID NIGHTTIME PREDATORS, THEY, TOO, HAVE SHIFTED.

THEY'VE SHIFTED THEIR BEHAVIOR.

IT'S JUST SIMPLY TOO HOT TO BE OUT THERE IN THE MIDDLE OF THE DAY.

SANJAYAN, VOICE-OVER: SO, THE SCHEDULE HAS BEEN TURNED UPSIDE-DOWN.

BUFFALO THAT WOULD NORMALLY ARRIVE AT DUSK NOW WAIT UNTIL DARKNESS AT 8 P.M. BEFORE COMING DOWN FOR A DRINK.

ELEPHANTS, WHO REGULARLY VISITED DURING THE MIDDLE OF THE AFTERNOON, ARE NOW MOST OFTEN APPEARING AROUND 9 P.M. ZEBRA, WHICH USED TO COME DOWN AT 11 A.M. EVERY DAY, ARE NOW MORE FREQUENTLY SPOTTED IN THE EARLY HOURS, AROUND 2 A.M. TO 4 A.M.

SO AT THIS TIME OF THE YEAR, NIGHTTIME IS THE NEW RUSH HOUR.

THE BUSY NIGHTS GIVE ME A CHANCE TO DO SOMETHING EXTRAORDINARY.

USING THE BLIND, I CAN ATTEMPT TO GET CLOSE TO AN AFRICAN GIANT.

THE INFRARED LIGHTS MEANS THAT THE CAMERAS CAN CAPTURE EVERYTHING, BUT I AM COMPLETELY BLIND.

[FROGS AND TOADS CROAKING] [WATER SPLASHING] THE CHORUS OF FROGS AND TOADS GIVE ME SOME COVER, BUT IT'S NOT LONG BEFORE HE DETECTS ME.

SANJAYAN: AND YOU CAN JUST FEEL ITS PRESENCE MORE THAN YOU CAN SEE IT.

SANJAYAN, VOICE-OVER: IT'S YOUNG A BULL ELEPHANT, AND HE KNOWS I'M HERE.

[WHISPERING] AND THOUGH HE CAN'T REALLY SEE US, HE CAN DEFINITELY SMELL US AND HE FOR SURE CAN HEAR US.

[TRUMPETS] RIGHT THERE.

IT'S OK.

IT'S OK, BUDDY.

SANJAYAN, VOICE-OVER: AND HE'S NOT ALONE.

IT'S BUFFALO.

SANJAYAN, VOICE-OVER: CAPE BUFFALO ARE NOTORIOUSLY AGGRESSIVE AND DON'T LIKE TO SHARE TERRITORY.

AND IT'S A STAND-OFF.

[ELEPHANT TRUMPETS] THIS IS FANTASTIC.

SANJAYAN, VOICE-OVER: AN ANGRY ELEPHANT LIKE THIS YOUNG MALE CAN USE HIS TUSKS TO PICK UP A BUFFALO AND TOSS IT IN THE AIR.

THIS TIME, THE BUFFALO BACKS DOWN.

BUT THE TWO POOLS WE BUILT AT THIS WATERHOLE MEANS THAT BOTH THESE GIANTS CAN GET A DRINK TONIGHT.

THE BUFFALO HAVE DECIDED TO DRINK FROM THIS WATERHOLE BECAUSE THE ELEPHANT IS DRINKING FROM THIS ONE.

AND YOU CAN SEE EVEN IN THIS SMALL SPACE, THE SEPARATION BETWEEN SPECIES.

YOU KNOW, THIS KIND OF INTERACTION IS WHAT'S SO FANTASTIC TO SEE AND YOU ONLY GET THAT KIND OF BEHAVIOR AT WATERHOLES, WHEN ANIMALS ARE FORCED--ARE FORCED INTO CLOSE PROXIMITY WITH ONE ANOTHER.

SANJAYAN, VOICE-OVER: AS THE BUFFALO RETREAT, THE YOUNG BULL BECOMES MORE AWARE OF US.

AN ELEPHANT'S HEARING IS INCREDIBLY SENSITIVE.

THEY'RE EVEN ABLE TO DETECT SEISMIC VIBRATIONS THROUGH THEIR FEET.

THE ELEPHANT IS RIGHT UP AT ME.

HE'S COMING RIGHT TOWARDS ME.

HE'S GOT HIS EARS OUT.

HE CAN HEAR ME.

SHH, SHH.

[WATER DRIPPING] HE'S REALLY CLOSE.

I CAN HEAR THE WATER DRIPPING FROM HIS TRUNK.

SANJAYAN, VOICE-OVER: HIS TRUNK COULD WEIGH AS MUCH AS 300 POUNDS AND IS ABLE TO HOLD 2 GALLONS OF WATER AT A TIME.

SO, IT'S NOT REALLY SURPRISING THAT HE'S TAKING LOTS OF TIMEOUTS, RESTING HIS TRUNK ON HIS TUSKS.

I MEAN, COME ON.

[BUBBLING] IT'S BLOWING BUBBLES, AND HE'S RIGHT THERE.

[SNORTING] HE'S COME CLOSER.

HE'S RIGHT ON TOP OF ME NOW.

I FEEL... [SNORTING] IT REALLY IS PRETTY MAGICAL.

SANJAYAN, VOICE-OVER: WITH HIS THIRST QUENCHED AND TERRITORY SUCCESSFULLY DEFENDED, THE YOUNG BULL LEAVES TRIUMPHANT.

IT WAS GREAT TO GET TO KNOW HIM AND HOPEFULLY HE'LL COME BACK SOON.

WITH FEWER LARGE ANIMALS COMING TO THE WATERHOLE DURING THE DAY, SMALLER CREATURES ARE TAKING OVER.

[BUZZING] MILLIONS OF INSECTS ARE SPOTTED BUZZING AROUND THE WATERHOLE.

AND WE'VE GOT NEW BIRDS DROPPING BY...

INCLUDING THE STEPPE EAGLE, WHICH BREEDS IN EASTERN EUROPE, BEFORE JOURNEYING NEARLY 6,000 MILES TO AFRICA.

AND EGYPTIAN GEESE THAT PAIR UP FOR LIFE.

ONCE ONE DIES, THE OTHER MOURNS IN SECLUSION AND OFTEN REFUSES TO MATE EVER AGAIN.

[GEESE CALLING] THE WATERHOLE IS A MUCH-NEEDED REFILLABLE AND RELIABLE WATER SOURCE FOR ALL THESE SPECIES, AND FOR SOME, IT COULD ALSO BE A SOURCE FOR FOOD.

WOW, LOOK AT THOSE GUYS.

OH, YELLOW-BILLED STORKS.

IT'S A WHOLE FLOCK OF THEM!

THESE ARE SUCH GREAT SHOTS OF THESE GUYS, AND YOU DON'T REALLY GET TO SEE THEM CLOSE UP LIKE THIS.

THEY'RE OUT THERE HUNTING RIGHT NOW.

THEY'RE ACTUALLY LOOKING FOR FISH OR FROGS AND LITTLE THINGS THAT SWIM THROUGH THE WATER AND THEY HUNT BY KEEPING THEIR BILLS OPEN LIKE THIS, AND THEY JUST SWIM IT THROUGH THE WATER, AND IF THEY FEEL A LITTLE FISH GO RIGHT BETWEEN THEM, THEY'LL JUST SNAP IT SHUT.

NOW, THEY DON'T KNOW THIS, BUT THIS WATERHOLE'S SO NEW THAT THERE'S PROBABLY NOT ANY FISH IN THERE YET.

SANJAYAN, VOICE-OVER: IN ANOTHER FEW WEEKS, THE RAINS WILL ARRIVE AND THE LANDSCAPE WILL FLOOD.

THAT'S WHEN WATERWAYS WILL OPEN UP FOR FISH TO FIND THEIR WAY TO THE WATERHOLE.

I THINK THEY'RE GONNA BE A BIT DISAPPOINTED.

SANJAYAN, VOICE-OVER: FISH EGGS CAN ALSO BE TRANSPORTED ON THE FEET OF THESE BIRDS, AS THEY MOVE FROM ONE WATER SOURCE TO ANOTHER.

SO JUST THE FACT THAT THESE STORKS ARE VISITING COULD VERY WELL MEAN THAT SOMETIME IN THE FUTURE WE'RE GONNA START SEEING BABY FISH IN THIS WATERHOLE.

SANJAYAN, VOICE-OVER: CAMERAMAN BOB POOLE IS STILL ON THE LOOKOUT FOR LERIAH AND HER CUBS.

HE'S HEARD FROM ONE OF THE MWIBA GUIDES THAT A CARCASS HAS BEEN FOUND.

THERE'S BEEN A KILL RIGHT HERE IN CAMP.

IT'S RIGHT DOWN HERE, JUST A FEW HUNDRED METERS, AND WE NEED TO GO CHECK IT OUT BECAUSE APPARENTLY IT'S A FULL-GROWN ADULT WATERBUCK, WHICH IS A SIZEABLE ANIMAL.

SANJAYAN, VOICE-OVER: THE CARCASS IS LESS THAN HALF A MILE FROM THE WATERHOLE.

SO BOB IS KEEN TO FIND OUT WHAT'S BEEN HUNTING.

IT'S REMARKABLE, REALLY.

THIS CARCASS IS GONE.

THERE'S NOT EVEN ANY EVIDENCE IT WAS EVER HERE.

THERE'S A TINY BIT OF A GUT PILE, CONTENTS, NO STOMACH.

SANJAYAN, VOICE-OVER: COULD THIS BE THE WORK OF LERIAH?

JUST LOOKING TO SEE IF THERE IS ANY LION PRINTS.

BUT SO FAR, I ONLY SEE HYENA.

HYENAS WILL JUST RIP THIS CARCASS TO PIECES.

AND WHEN YOU LOOK AT THEIR JAWS, THEY'RE EXTREMELY WIDE HERE, AND THEY HAVE VERY STRONG MUSCLES ON THE TOP OF THEIR HEADS AND THEY ARE ABLE TO CRACK RIGHT THROUGH BONES, AND THEY ACTUALLY EAT THEM.

THAT'S WHY WHEN YOU SEE THEIR DUNG, IT'S OFTEN JUST WHITE, BECAUSE THEY ABSORB SO MUCH CALCIUM FROM THE BONES THAT THEY EAT.

BUT JUST GOES TO SHOW YOU THAT NOTHING IS WASTED OUT HERE.

SANJAYAN, VOICE-OVER: IT WAS FOUND LAST NIGHT, AND A GUIDE HAS PLACED A CAMERA TRAP ON IT.

BOB WANTS TO CONFIRM IF THIS IS A HYENA KILL AND HOW MANY THERE MIGHT BE IN THE AREA.

GUESS WHAT.

THEY CAME IN THE DAYLIGHT.

OK, HERE WE GO.

HYENA COMING ON.

OH, YEAH, BEAUTIFUL SHOT.

HA!

STARING STRAIGHT AT THE CAMERA NOW.

OH, WOW, HERE IT GOES.

AAH, ONE HYENA JUST STRUGGLING TO DRAG THAT, BUT DOING IT.

OH, THAT'S COOL.

FLIPPED IT OVER.

I WAS THINKING IT WOULD HAVE BEEN A WHOLE, YOU KNOW, GROUP OF HYENAS THAT CAME ON FIRST, BUT IT'S JUST ONE INDIVIDUAL, BUT IT SHOWS YOU THE STRENGTH OF THIS ANIMAL LIKE DRAGGING THAT HUGE CARCASS AND CONSUMING TREMENDOUS AMOUNTS OF MEAT.

A HYENA CAN EAT 15 KILOGRAMS OF MEAT IN ONE GO, WHICH IS 25% OF ITS BODY WEIGHT.

PHENOMENAL TO THINK OF.

WOW, THIS GUY'S REALLY LUCKY HE'S NOT HAVING TO SHARE IT AT ALL AT THE MOMENT.

OH, HANG ON.

UM...

THERE'S ANOTHER HYENA IN THE BACKGROUND THERE.

OH, HERE WE GO.

HA HA!

HE'S BEEN DISCOVERED AND WE'VE GOT 1, 2, 3, 4 HYENAS.

THEY'RE REALLY RIPPING INTO IT.

ALL RIGHT, THIS NOW MAKES SENSE.

I DIDN'T THINK ONE HYENA COULD EAT THAT WHOLE THING.

[HYENA SQUEALING] ONE HAS JUST TAKEN OFF WITH THE HIND QUARTER.

SO THAT'S HOW IT GOES.

BIT BY BIT, THE THING IS GONE.

YOU KNOW, THEY CAN DEVOUR THIS CARCASS IN A VERY SHORT AMOUNT OF TIME.

SANJAYAN, VOICE-OVER: WORKING TOGETHER TO TAKE DOWN AND CONSUME LARGE PREY IS A SURE SIGN THAT HYENAS ARE GROWING IN CONFIDENCE IN WHAT USED TO BE LION TERRITORY.

IT'S NOT GOOD NEWS FOR THE LIONESS LERIAH AND HER CUBS.

[THUNDER] THAT NIGHT, A LONE HYENA RETURNS, BUT IT'S A FRONT RUNNER ON A SCOUTING MISSION.

WITHIN A MATTER OF MINUTES, A WHOLE CLAN DESCENDS ON OUR WATERHOLE.

[HYENAS CALLING] HOW MANY ARE THERE?

I THINK THERE'S 8?

SANJAYAN, VOICE-OVER: DR. MEREDITH PALMER HAS BEEN STUDYING AFRICA'S CARNIVORES FOR MORE THAN A DECADE.

SHE CAN HELP ME UNDERSTAND HOW THE CLAN MIGHT BE IMPACTING LIFE AT THE WATERHOLE.

SO THESE WHOOPING CALLS THAT THEY'RE GIVING ARE A LONG-DISTANCE CALL THAT THEY USE TO SORT OF RALLY THE TROOPS AND BRING EVERYONE TOGETHER.

SANJAYAN, VOICE-OVER: SPOTTED HYENAS ARE SOMETIMES KNOWN AS "LAUGHING HYENAS" BECAUSE THEY HAVE A DISTINCTIVE CALL THAT SOUNDS LIKE HUMAN LAUGHTER.

[HYENA CALLING] THEY CAN MAKE UP TO 12 DIFFERENT VOCAL SOUNDS, BUT THESE CAN BE MODULATED TO CREATE EVEN MORE MEANING.

HOW BIG DO THESE CLANS GET?

YEAH, SO CLANS CAN BE DOZENS OF INDIVIDUALS.

IN THESE SUPER-CLANS LIKE, YOU KNOW, SPREAD OUT OVER THE LANDSCAPE, WOULD THERE BE INDIVIDUAL RECOGNITION?

YEAH, SO THEY RECOGNIZE RELATIVES, EVEN DISTANT RELATIVES.

THERE'S A HIERARCHY WITHIN THESE CLANS BASED ON THE MATRILINE.

SO YOU HAVE MORE- DOMINANT FEMALES AND LESS-DOMINANT FEMALES.

SO THEY'RE A VERY SOCIAL CREATURE AND THEY HAVE THAT SOCIAL AWARENESS OF WHO THEY ARE RELATIVE TO THIS LARGER CLAN STRUCTURE.

SANJAYAN, VOICE-OVER: HYENAS ARE HIGHLY TERRITORIAL ANIMALS.

NOW THAT THE CLAN HAS DESCENDED ON THE WATERHOLE, IT IS LIKELY THEY COULD CLAIM THIS AREA AS THEIR OWN.

[HYENAS CALLING] THE SITUATION COULD EASILY GO FROM BAD TO WORSE.

MEREDITH BELIEVES THAT THERE COULD BE EVEN MORE HYENAS NEARBY.

JUST THEIR SCENT ALONE COULD PUT OFF OTHER ANIMALS...

WHICH COULD BE WHY, IN THE DAYS FOLLOWING THE HYENA CLAN VISIT, ALMOST NOTHING COMES TO DRINK AT THE WATERHOLE.

I NEED TO FIND OUT MORE ABOUT THESE DOMINANT HYENA, SO IN THE EARLY EVENING, AS TEMPERATURES DROP, I TAKE ADVANTAGE OF THE COOLER AIR TO JOIN BOB TO FIND OUT WHERE THEY LIVE.

YESTERDAY, BOB SPOTTED A HYENA DEN WITH YOUNG CUBS, JUST OVER A MILE FROM OUR WATERHOLE... NO, HANG ON NOW.

BUT FINDING IT AGAIN IS PROVING TRICKY.

I THINK I WENT--I MIGHT HAVE GONE PAST IT, YOU GUYS.

NO.

YEAH, YOU HAVE.

DO YOU KNOW WHY?

BECAUSE THAT OTHER TERMITE MOUND, I SAID "IS IT THAT ONE?"

THIS ONE.

NO, THAT'S NOT IT.

WE'RE LOOKING FOR A HYENA DEN THAT BOB ESSENTIALLY STUMBLED UPON, BUT HE LIKES TO SAY HE FOUND IT AND JUST ABOUT NOW, RIGHT AT DUSK, THE PUPS MIGHT COME OUT.

IT MIGHT BE THE SAME HYENAS THAT ARE COMING TO OUR WATERHOLE, WHICH IS NOT VERY FAR AWAY.

SANJAYAN, VOICE-OVER: DEN FINALLY FOUND, WE PUT OUT A REMOTE CAMERA.

[WHISPERING] IT'S A BIT STRANGE.

IMAGINE WAKING UP IN YOUR BEDROOM ONE DAY AND THERE'S A GIANT CAMERA IN THERE, BUT THE IDEA IS IF WE GET THIS CAMERA KIND OF CLOSE, THEN WE CAN BACK OFF AND LET THE CAMERA DO ALL THE WATCHING FOR US AND WE CAN GO BACK INTO THE TRUCK AND WATCH THE PUPS FROM THERE.

OK, LET'S LEAVE IT.

GOOD.

SANJAYAN, VOICE-OVER: WITH THE CAMERAS ROLLING, WE CAN GET OUT OF SIGHT.

BOTH: THAT'S FANTASTIC.

THAT'S REALLY NICE.

YEAH, THAT'S GREAT.

SANJAYAN: THAT'S A YOUNG ONE, ALL THAT WHITE FUR.

VERY CLEAN.

JUST TROTTED OUT OF ITS DEN, SNIFFING.

SANJAYAN, VOICE-OVER: THE REST OF THE DEN ARE KEEN TO FOLLOW.

OH, THERE'S 4, 4 PUPS.

OH, IS THERE?

4 HYENA PUPS.

I'M GONNA GUESS A FEW MONTHS OLD, MAYBE A COUPLE MONTHS OLD, 3 MONTHS OLD.

LOOK AT THAT.

[HYENAS GROWLING AND SQUEALING] WHEN THE HYENA PUPS ARE REALLY SMALL, THE MOTHER MOVES THEM VERY FREQUENTLY.

THEY USUALLY LOVE TO DEN IN THESE TERMITE MOUNDS OR IN OLD WARTHOG BURROWS, AND THEY'LL MOVE THEM BECAUSE THEY HAVE A VERY STRONG SCENT AND THEY DON'T WANT OTHER PREDATORS TO KNOW THAT THEY'RE DENNING THERE.

IN THIS CASE, THESE PUPS ARE A BIT OLDER.

I THINK THOSE PUPS CAN MOVE ON THEIR OWN NOW.

SANJAYAN, VOICE-OVER: AS THE LIGHT GOES, WE ACTIVATE THE CAMERA'S INFRARED.

THE PUPS BECOME BOLDER.

ONE THING I'VE NOTICED IS THERE'S A LOT OF HYENAS, SO IT'S OBVIOUSLY GOOD HABITAT.

I MEAN, THESE TERMITE MOUNDS MAKE EXCELLENT DEN SITES, RIGHT.

YEAH.

THESE HYENAS ARE IN BIG CLANS BECAUSE I BET YOU THEY FEED QUITE A BIT ON SOME BIG ANIMALS.

CLAN SIZE IS OFTEN DETERMINED BY WHAT ANIMALS THEY'RE SPECIALIZING ON.

SANJAYAN, VOICE-OVER: CHOOSING A DEN SITE SO CLOSE TO OUR WATERHOLE AND THEREFORE CLOSER TO PREY IS A KEY SURVIVAL STRATEGY THAT WILL HELP THIS CLAN GROW STRONG IN NUMBERS.

BUT FOR THE COMMUNITY AROUND THE WATERHOLE, IT'S BAD NEWS.

WITH HYENAS AN EVER-INCREASING PRESENCE, TRAFFIC AT THE WATERHOLE IS SLOW.

[WATER SPLASHING] BUT THIS EVENING, THERE'S ONE, LONE, NIGHTTIME VISITOR.

IT'S A MALE ELEPHANT WHO'S FAR TOO BIG FOR THE HYENAS TO TAKE DOWN.

A CLOSER LOOK AT HIM REVEALS SOMETHING INCREDIBLE.

SANJAYAN: I MEAN, THAT'S AMAZING TO SEE AN ELEPHANT WITH HALF HIS TRUNK GONE.

MHAPPA: UH-HUH, UH-HUH, YEAH.

WE'VE SEEN HIM FOR ABOUT 4 YEARS.

SANJAYAN, VOICE-OVER: NUHU KNOWS THE SAD STORY BEHIND THIS ELEPHANT'S HALF-TRUNK.

MHAPPA: IT'S AMAZING THAT HE'S STILL SURVIVING.

THE SNARES HAVE BEEN SET BY THE POACHERS.

SANJAYAN, VOICE-OVER: SNARES ARE OFTEN SET UP ALONG GAME TRAILS AND IN LONG GRASS.

THEY PUT THEIR TRUNK IN THERE, IT GOT CAUGHT.

YEAH, IT GET CAUGHT AND THAT'S HOW-- AND IT'S LIKE A WIRE LOOP RIGHT?

SANJAYAN, VOICE-OVER: THIS POOR GUY WAS SNAGGED BY HIS TRUNK, CAUSING TERRIBLE DAMAGE.

AND AS IT GETS STRONGER, THEY BECOME SO AGGRESSIVE AND THEN EVENTUALLY JUST PULL, PULL AS HARD AS...

HE HAS BEEN WITH THAT KIND OF WOUND FOR QUITE SOME TIME NOW.

SANJAYAN, VOICE-OVER: LIFE IS CHALLENGING FOR THIS INDIVIDUAL.

USING THEIR TRUNKS, ELEPHANTS ARE CAPABLE OF LIFTING OVER 600 POUNDS, SOMETHING HE WILL NEVER BE ABLE TO DO.

AND STILL ABLE TO DRINK.

I MEAN, THAT'S THE PART THAT WAS SURPRISING TO ME, THAT HE COULD STILL, EVEN WITH THE HALF-TRUNK, SORT OF GET IT IN THE WATER AND SUCK UP ENOUGH WATER AND SORT OF SPRAY IT INTO HIS MOUTH.

YEAH, IT'S NOT BEING DONE VERY EFFICIENTLY COMPARED TO OTHER ELEPHANTS THAT HAVE GOT A COMPLETE TRUNK.

AS SOON AS HE TIP THAT TIP OF THE TRUNK IN THE WATER, THEN HE WILL BE ABLE TO SUCK, BUT NOT THE SAME AMOUNT.

SANJAYAN, VOICE-OVER: AT THIS TIME OF YEAR, MANY NATURAL WATER SOURCES ARE DRIED UP AND HARDER FOR HIM TO REACH.

SO WATER DEEP ENOUGH FOR HIM TO WADE INTO WILL ALLOW HIM TO SURVIVE.

I FEEL A LITTLE SAD.

YEAH.

IT'S VERY PAINFUL TO PICTURE ABOUT HOW IT MIGHT HAVE HAPPENED AND HOW HORRIBLE THE SCENARIO WAS.

BUT, YEAH.

IS VERY SAD THAT TO KNOW THAT HUMAN ARE JUST BEHIND THE INSTANCE.

SANJAYAN, VOICE-OVER: POACHING STILL REMAINS A MAJOR CHALLENGE IN THE REGION.

IT HAS A LASTING IMPACT ON MANY ANIMALS, LIKE HALF-TRUNK.

AS DAY BREAKS, AN UNLIKELY SPECIES IS PROVING TO BE A FORCE TO BE RECKONED WITH.

[GEESE SQUAWKING] EGYPTIAN GEESE ARE AGGRESSIVELY TERRITORIAL, ESPECIALLY AT THIS TIME OF YEAR AS BREEDING BEGINS.

THIS MATING PAIR IS PROTECTING THEIR PATCH FROM OTHER GEESE, BUT THEY'RE ALSO AN INTIMIDATING PRESENCE FOR MUCH BIGGER ANIMALS COMING TO THE WATER.

EVEN TOP PREDATORS LIKE THIS HUGE MARTIAL EAGLE HAVE LITTLE PATIENCE FOR THIS COUPLE.

BETWEEN THE DOMINEERING GEESE AND THE NIGHTTIME HYENA CLAN, THE USUAL ANIMAL COMMUNITY APPEARS TO BE STAYING AWAY.

[HYENAS CALLING] AND OVER THE NEXT FEW NIGHTS, HYENA VISITS RAMP UP.

THEY'RE SO CONFIDENT NOW, IT'S LIKE THEY OWN THE PLACE.

[HYENA SNIFFING] AND ONE SELF-ASSURED HYENA APPEARS WITH EVIDENCE THAT IT'S BEEN HUNTING NEARBY.

IT LOOKS LIKE HE'S TRYING TO COVER UP ANY TRACE OF HIS MIDNIGHT FEAST.

HE CARRIES IT INTO THE WATER, BUT THEN DECIDES TO STASH IT IN THE BUSHES... BEFORE RETURNING TO WASH DOWN HIS FEAST.

SPOTTED HYENAS ARE NOT ONLY FIERCELY INTELLIGENT, THEY ARE INQUISITIVE AS WELL.

FOR THIS ONE, CURIOSITY HAS BROUGHT HIM UP CLOSE TO OUR CREW CAMP, JUST HALF A MILE FROM THE WATERHOLE.

THEY'RE EVEN BRAVE ENOUGH TO COME RIGHT UP TO OUR TENTS, HOWLING THROUGH THE NIGHT.

[HYENAS HOWLING] AND THEY'RE NOW USING THE SAME TRAILS WE USE TO GET IN AND OUT OF THE CAMP.

DESPITE THE HYENAS GETTING BRAVER, BOLDER AND MORE CURIOUS, OVER THE NEXT FEW NIGHTS WE STILL MANAGE TO SPOT SOME NEW SPECIES AT THE WATERHOLE.

[CHIRPING] HORSESHOE BATS, WHICH CAN EAT UP TO 3,000 INSECTS A NIGHT.

[CROAKING] AND THESE AFRICAN RED TOADS DON'T DRINK.

THEY CAN ABSORB THE WATER DIRECTLY THROUGH THEIR SKIN.

IT'S GREAT TO SEE THAT DESPITE THE HYENAS, THERE'S STILL LIFE AT THE WATERHOLE.

BUT SINCE THE CLAN INVADED, THERE'S BEEN NO SIGN OF LIONESS LERIAH AND HER CUBS.

BOB HAS EXPANDED HIS SEARCH AREA.

EVENTUALLY, HE SPOTS EVIDENCE OF LIONS, 10 MILES FROM THE WATERHOLE.

THERE'S A CARCASS RIGHT THERE.

MAYBE SHE'S MADE A KILL IN HERE.

POOLE: THERE SHE IS.

MAYBE THE CUBS ARE THERE, TOO.

I MEAN, I HAVEN'T SEEN THESE CUBS IN SO LONG.

I GUESS WE JUST HAVE TO STAY HERE AND SEE WHAT HAPPENS.

OH, OH, OH, OH.

I JUST SAW MOVEMENT THERE.

AH!

THE CUBS ARE RIGHT THERE.

OH, MY GOD.

THEY'RE RIGHT THERE.

I CAN BARELY SEE IT.

OH, MY GOD.

LET'S SEE.

HOW MANY?

1, 2, 3 LITTLE CUBS.

YOU KNOW, YOU GET SO INVESTED IN THIS STUFF AND YOUR MIND PLAYS TRICKS WITH YOU, LIKE THEY'RE DEAD AND IT'S LIKE, WOW.

IT'S JUST...

IT ACTUALLY BECOMES QUITE EMOTIONAL, YOU KNOW, TO SEE THEM AGAIN.

SANJAYAN, VOICE-OVER: LERIAH HAS SUCCESSFULLY MOVED HER CUBS AWAY FROM THE HYENAS.

LION TERRITORIES CAN COVER OVER 200 SQUARE MILES, AN AREA EQUIVALENT TO THE CITY OF CHICAGO.

AS LONG AS SHE KEEPS ON THE MOVE, THE CUBS' CHANCE OF SURVIVAL WILL INCREASE AS THEY GROW.

BUT OTHER ANIMALS CAN'T MOVE OUT OF THE AREA SO EASILY.

THEY HAVE NO CHOICE BUT TO RISK THEIR LIVES COMING DOWN TO THE HYENA-DOMINATED WATERHOLE.

THIS VERVET MONKEY MUM NEEDS TO DRINK EVERY DAY IN ORDER TO KEEP PRODUCING NUTRIENT-RICH MILK FOR HER YOUNG.

THE MONKEYS ARE SAFE FROM HYENAS WHILE RESTING UP IN THE TREES, BUT ONCE THEY'RE ON THE GROUND, THEY MUST BE CAREFUL.

LUCKILY FOR THIS MUM, THE REST OF THE TROOP IS NEARBY TO KEEP WATCH.

WITH THE COAST CLEAR, SHE MAKES IT TO THE WATERHOLE.

THE BABY GETS FLUIDS FROM DRINKING THEIR MOTHER'S MILK, SO AS LONG AS THE MOM GETS ENOUGH WATER, THE BABY WILL BE ABLE TO SURVIVE THE HEAT.

OUR WATERHOLE HAS BECOME A LIFELINE FOR MANY ANIMALS...

INCLUDING THE ELEPHANT WITH HALF A TRUNK.

[WATER SPLASHING] HE HAS RETURNED, AND INCREDIBLY, HE'S FOUND A HERD TO DRINK WITH.

ELEPHANTS ARE HIGHLY SOCIAL, AND OTHER MEMBERS OF THE GROUP ARE KEEN TO INTERACT WITH HIM.

THEY USE THEIR TRUNKS TO COMMUNICATE, SMELLING AND TOUCHING EACH OTHER'S MOUTHS.

IT'S ESSENTIALLY AN ELEPHANT HANDSHAKE.

HALF-TRUNK DOES HIS BEST TO RETURN THE GESTURE, MAKING A VITAL SOCIAL BOND AND CONFIRMING HALF-TRUNK AS ONE OF THE FAMILY.

DURING THE HOTTEST TIME OF YEAR, WE'VE SEEN NUMBERS INCREASE AND THEIR VISITS INTENSIFY BOTH DAY AND NIGHT...

BUT WE STILL DON'T KNOW EXACTLY HOW MANY HYENA THERE ARE IN THIS CLAN.

SANJAYAN: SO WE SEE ALL THESE HYENAS AT THE WATERHOLE PRETTY MUCH EVERY DAY, BUT WE HAVEN'T REALLY BEEN ABLE TO GET A SENSE OF HOW MANY HYENAS ARE OUT AND ABOUT IN THIS ENVIRONMENT, RIGHT, MEREDITH, AND THAT'S WHY YOU'VE GOT THIS INGENIOUS IDEA OF HOW TO TRY AND COUNT THE HYENAS THAT ARE ACTUALLY OUT HERE.

AND PLAYING BACK SOUND IS BASICALLY PLAYING BACK SOUNDS OF HYENAS OR SOMETHING ELSE?

YEAH, SO WE'RE DOING TWO DIFFERENT KINDS OF PLAYBACKS.

SO ONE SET OF CALLS IS PREY ANIMALS IN DISTRESS, BUT WE'RE ALSO PLAYING A SET OF CALLS THAT ARE HYENA SOCIAL CALLS.

RIGHT.

SO THEY'RE CALLS THAT WERE COLLECTED IN DIFFERENT PLACES.

THEY'RE NOT HYENAS THESE HYENAS KNOW.

OH, I SEE.

SO IF THEY HEAR IT, THEY'LL THINK A NEW CLAN HAS COME IN-- YEAH, EXACTLY.

AND THEY'LL COME TO INVESTIGATE.

THEY'RE COMING TO SEE WHO THESE NEW HYENAS ARE.

GOT IT.

MM-HMM.

OK, SO DO YOU WANT TO TRY AND PLAY SOME CALLS?

[RECORDED HYENA CALLS] SO, YOU BASICALLY USE THIS TECHNIQUE WHEN YOU'RE ACTUALLY TRYING TO COUNT PREDATORS, LIKE HYENAS IN THE SERENGETI?

YEAH, SO YOU CAN DO THIS FOR HYENAS, YOU CAN DO THIS FOR LIONS.

PLAYING THE CALLS OF UNFAMILIAR INDIVIDUALS OFTEN WILL BRING IN CARNIVORES TO INVESTIGATE FROM THE SURROUNDING LANDSCAPE.

SANJAYAN, VOICE-OVER: HYENAS COME TOGETHER EN MASSE FOR TWO KEY EVENTS: EITHER FOR A FEAST, OR WHEN THEY'RE TRYING TO DEFEND THEIR TERRITORY.

TONIGHT, WE'RE ATTEMPTING TO LURE THEM IN WITH CALLS FOR BOTH.

MEREDITH, DO YOU THINK PLAYING THESE CALLS ENDS UP STRESSING THESE ANIMALS OUT?

I DON'T THINK SO, BECAUSE WE'RE NOT DOING IT-- WE'RE NOT BLASTING THESE CALLS 24 HOURS A DAY.

WE'RE NOT DOING IT EVERY WEEK.

IT'S A VERY ACUTE, MOMENTARY STRESSOR.

IT'S 15 MINUTES OF THEIR LIFE.

THEY CAME TO INVESTIGATE A STRANGE NOISE, AND THEN THEY'RE GONNA GO ON WITH THEIR LIVES.

BUT YOU DON'T WANT TO DO THIS AS A MATTER OF PRACTICE.

IF WE WERE PLAYING THIS MORE THAN A COUPLE OF TIMES, THEY WOULD QUICKLY REALIZE THAT WHAT'S CALLING THEM IN ISN'T STRANGE, YOU KNOW, THREATENING, INTERESTING HYENAS, IT'S ACTUALLY A BUNCH OF HUMANS IN A TRUCK, AND THEY QUICKLY LEARN TO START IGNORING CALLS LIKE THIS.

SO WE CAN'T DO THIS MORE THAN A COUPLE MORE TIMES WITHOUT THEM CATCHING ON.

SANJAYAN, VOICE-OVER: OUR 100-DECIBEL SOUND PUNCHES FAR AND WIDE THROUGH THE NIGHT.

YEP.

THEY'RE HERE.

[HYENA CALLING] THAT'S THE REAL ONE.

OH, HE'S SO CLOSE.

THIS HAS GOTTA BE THE STRANGEST THING I'VE EVER DONE IN MY LIFE.

[HYENAS CALLING] THEN IF WE COULD START SCANNING TO SEE HOW MANY WE HAVE.

SANJAYAN: IF I DO A QUICK... YEAH, THAT'D BE BRILLIANT.

OH, WOW.

1, 2, 3, 4.

4?

OVER THERE.

YOU CAN SEE HER FACE.

I CAN SEE 5.

SANJAYAN, VOICE-OVER: WITHIN 8 MINUTES OF THE CALLS, OUR TRUCK IS SURROUNDED BY HYENAS.

THAT'S INCREDIBLE HOW QUICKLY THEY SHOWED UP.

SANJAYAN, VOICE-OVER: THEY ARRIVED SO QUICKLY, IT LEADS US TO BELIEVE THAT THESE COULD BE THE SAME ADULTS FROM THE DEN WE VISITED PREVIOUSLY.

WOW.

SO THAT MUST BE LIKE A LITTLE RESIDENT CLAN.

SANJAYAN, VOICE-OVER: TONIGHT HAS ALLOWED US TO GATHER DATA ON HOW MANY HYENAS ARE USING THE WATERHOLE.

ASSUMING THAT ONLY 1/3 OF THE CLAN WOULD BE RESPONDING TO THE CALL, LEAVING THE OTHERS TO LOOK AFTER THE YOUNG OR HUNT ELSEWHERE, MEREDITH BELIEVES THERE COULD BE AS MANY AS 25 IN THIS CLAN.

AS THE DAYS HAVE GOT HOTTER, THE NUMBER OF HYENA VISITS HAS PEAKED TO AROUND 70.

DESPITE THE NEAR CONSTANT PRESENCE OF HYENA IN THE AREA, WE'VE STILL MANAGED TO SEE AND LOG A HUGE VARIETY OF ANIMALS.

NOW AT THE HOTTEST TIME OF THE YEAR, AS THE RAINS GET REALLY CLOSE, THE SPECIES LIST HAS CONTINUED TO GROW.

WE HAVE A TOTAL OF 83 DIFFERENT SPECIES THAT HAVE COME TO THE WATERHOLE, AND THAT DIVERSITY IS ADDING NEW THINGS THAT WE HAD NEVER SEEN BEFORE.

SANJAYAN, VOICE-OVER: BUT EVERYTHING IS ONCE AGAIN ABOUT TO CHANGE.

[THUNDER] YOU KNOW, YOU CAN SEE THAT RAIN JUST BUILD UP OVER THERE, AND YOU CAN FEEL THAT HUMIDITY.

THERE'S VERY LITTLE WIND RIGHT NOW, AND IT JUST FEELS LIKE THIS ENTIRE LAND IS JUST WAITING FOR THAT RELIEF THAT THE RAIN WILL BRING.

[THUNDER] SANJAYAN, VOICE-OVER: IN THE COMING MONTHS, 40 INCHES OF RAIN IS EXPECTED TO FALL IN THIS REGION.

THAT'S MORE THAN THE CITY OF SEATTLE GETS IN AN ENTIRE YEAR.

THE RELENTLESS DOWNPOUR DELIVERS THE MOST DRAMATIC SEASONAL CHANGE YET.

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