NARRATOR: 200,000 YEARS AGO, A NEW SPECIES EMERGED ON THE AFRICAN LANDSCAPE... HOMO SAPIENS.

MODERN HUMANS.

US.

TODAY, THERE ARE 7 BILLION OF US LIVING ACROSS PLANET EARTH.

THIS IS THE STORY OF OUR JOURNEY FROM CONTINENT TO CONTINENT: HOW WE LEFT AFRICA, CROSSED ASIA, REACHED AUSTRALIA, AND COLONIZED EUROPE.

THE FINAL FRONTIER WAS AMERICA, THE LAST CONTINENT TO BE CONQUERED.

IT'S ONE OF THE GREAT MYSTERIES OF ARCHAEOLOGY.

WHO FIRST SET FOOT ON AMERICAN SOIL?

WHEN AND HOW DID THEY GET HERE?

WOMAN: AS THEY MOVED FURTHER AND FURTHER SOUTH, THEY WOULD KNOW THAT THEY WERE TRULY THE FIRST PEOPLE TO EXPERIENCE THOSE LANDSCAPES.

MAN: THESE RIVERS WOULD HAVE PROVIDED ALL THE RESOURCES THAT COASTAL PEOPLES NEEDED TO EXPLORE DEEP INTO THE INTERIOR AND ULTIMATELY COLONIZE ALL OF NORTH AMERICA.

SECOND MAN: AS A SCIENTIST, IT'S SUPER-EXCITING IF THERE IS A CONTROVERSY BECAUSE THE RESULT MATTERS.

IT MEANS SOMETHING.

IT'S IMPORTANT.

NARRATOR: WHO WERE THESE FIRST AMERICANS?

AND WHAT BECAME OF THEM?

THEIR STORY IS OUR STORY.

[BIRDS SCREECHING] NARRATOR: THE YUCATAN PENINSULA, MEXICO... 13,500 YEARS AGO.

A CEREMONY TAKES PLACE DEEP WITHIN A CAVE.

A YOUNG WOMAN IS BEING BURIED BY HER CLAN.

ARCHAEOLOGISTS KNOW HER AS EVA.

WHEN ALIVE, SHE WAS A HUNTER-GATHERER... [BLOWS] LIKE ANY OTHER PREHISTORIC PERSON, BUT EVA IS SPECIAL TO US.

[BLOWS] SHE CAN LAY CLAIM TO BEING THE FIRST AMERICAN.

NO OTHER REMAINS HAVE BEEN FOUND ANYWHERE IN THE AMERICAS AS OLD AS EVA.

EVA'S BONES WERE DISCOVERED UNDERWATER...

IN A VAST CAVE SYSTEM BENEATH THE FORESTS OF YUCATAN.

THERE ARE CHAMBERS HERE THE SIZE OF CATHEDRALS AND TUNNELS SO SMALL, IT'S BARELY POSSIBLE TO PASS THROUGH.

MEXICAN ARCHAEOLOGISTS HAVE BEEN EXCAVATING IN THESE CAVES SINCE 2008.

LEADING THE TEAM IS ARTURO GONZALEZ.

GONZALEZ: FOR ME, IT'S LIKE, UH, THE BEST WAY TO MAKE ARCHAEOLOGY BECAUSE YOU DON'T-- YOU DON'T NEED TO DIG, YOU DON'T--YOU DON'T HAVE DUST, AND, UH, EVERYTHING IS CLEAR.

[MUFFLED SHOUTING] NARRATOR: MOST OF THE BONES THEY FIND ARE FROM ANIMALS, BUT IN AMONG THEM ARE THE REMAINS OF PREHISTORIC HUMANS.

GONZALEZ: WE SPEND A LOT OF TIME DIVING, EXPLORING.

WHEN FINALLY YOU FIND SOME HUMAN REMAINS, IT'S--IT'S LIKE A LOTTERY.

IT'S, UH, "WOW, THANKS, GOD," NO?

YOU HAVE THIS GREAT OPPORTUNITY TO TOUCH THIS EVIDENCE.

IT'S LIKE A CONNECTION BETWEEN THE PAST AND THE FUTURE.

IMPRESSIVE.

NARRATOR: BUT WHY ARE THERE HUMAN BONES UNDERWATER?

THEY WEREN'T WASHED IN.

THEY MUST HAVE BEEN LEFT HERE WHEN THE CAVES WERE DRY.

DURING THE ICE AGE, SO MUCH OF THE WORLD'S WATER WAS FROZEN IN GREAT SHEETS OF ICE THAT SEA LEVELS WERE LOWER THAN TODAY-- UP TO 400 FEET LOWER-- PUSHING BACK THE COASTLINE, CHANGING THE SHAPE OF THE AMERICAS.

AT THAT TIME, THE CAVE SYSTEM IN THE YUCATAN WOULD HAVE BEEN DRY ENOUGH FOR PEOPLE TO ENTER AND BURY THEIR DEAD.

THE DRY PHASE ENDED 8,000 YEARS AGO.

SINCE THEN, THE CAVES HAVE BEEN SUBMERGED, SEALING IN AND PROTECTING ANY HUMAN REMAINS.

IN TOTAL, GONZALEZ AND HIS TEAM HAVE RECOVERED 8 SKELETONS FROM THE CAVE SYSTEM.

IT'S THE LARGEST COLLECTION OF PREHISTORIC HUMANS FOUND AT ANY ONE SITE IN NORTH AMERICA.

THE STAR FIND IS THIS ONE-- EVA OF NAHARON.

[SPEAKING SPANISH] INTERPRETER: THIS WAS THE FIRST SKELETON THAT WE FOUND IN THE CAVES.

IT'S ALSO THE OLDEST.

WE KNOW THAT THIS IS A YOUNG WOMAN BECAUSE WE HAVE THE HIP BONES, WHICH ARE VERY DIFFERENT FROM THOSE OF MEN.

THE SKULL IS ALSO A GOOD INDICATOR OF THE SEX OF A PERSON.

THIS SKULL IS VERY DELICATE, CORRESPONDING WITH A YOUNG WOMAN.

NARRATOR: SHE WAS 4'7" TALL WHEN ALIVE AND STILL IN HER 20s WHEN SHE DIED.

RADIOCARBON-DATING OF HER BONES SUGGESTS THAT HAPPENED 13,500 YEARS AGO.

ARCHAEOLOGISTS BELIEVE EVA WAS PART OF A LARGER CLAN OF NOMADS.

[BLOWS] THEY LIVED IN THE FORESTS... [BLOWS] UP TO 40 MILES FROM THE CAVE SYSTEM.

[ANIMAL SCREECHING] [RATTLING] THEY ONLY CAME INTO THE CAVES TO BURY THEIR DEAD.

WHEN EVA WAS DISCOVERED, HER SKELETON WAS INTACT AND UNDISTURBED.

SHE'D BEEN DELIBERATELY PLACED THERE, A 1/4 OF A MILE FROM THE NEAREST OPENING.

[BIRDS CHIRPING] THE EVIDENCE SUGGESTS EVA WAS LAID TO REST IN SOME KIND OF RITUAL BURIAL.

IT'S THE EARLIEST SIGN OF SPIRITUALITY ANYWHERE IN NORTH AMERICA.

BUT WHY GO TO SUCH LENGTHS AND PERFORM A CEREMONY IN THE DARK, A 1/4 OF A MILE INTO THE CAVE?

NORMALLY IS THE DEEPEST PART OF THE CAVE, NORMALLY IS VERY FAR FROM THE ENTRANCE, BUT WE DON'T KNOW.

WE--WE DON'T KNOW SPECIFICALLY WHY THEY CHOOSE THESE SPECIFIC PLACES.

[MAN CHANTING] [CHANTING CONTINUES] NARRATOR: OCTAVIO RETTIG IS A MODERN-DAY SHAMAN.

HE BELIEVES THE DEEPEST CHAMBERS WERE PORTALS TO A SPIRIT WORLD... [INDISTINCT] WHERE SHAMANS COMMUNED WITH THE SPIRITS, USING PSYCHOTROPIC DRUGS.

[INDISTINCT] TODAY, ARTURO GONZALEZ IS SIMULATING THE EFFECT WITH A COMPOUND EXTRACTED FROM THE GLANDS OF A MEXICAN TOAD.

[CHANTING IN SPANISH] WOW.

[DISTORTED LAUGHTER] [CHANTING] GONZALEZ: I'M AN ANTHROPOLOGIST, I'M A PALEONTOLOGIST.

I'M VERY, VERY SURE ABOUT THE RATIONALISM, BUT NOW I UNDERSTAND BETTER WHY THEY CHOOSE THESE SPECIFIC PLACES TO-- IN ORDER TO MAKE THESE BURIALS, SO-- OR MAKE THESE, UH, CONNECTIONS WITH THE SOULS, NO?

[WATER DRIPPING] NARRATOR: SUCH RITUALS 13,500 YEARS AGO ARE THE EARLIEST FLICKERINGS OF A CULTURE ANYWHERE IN THE AMERICAS.

BUT FOR ARCHAEOLOGISTS, THAT'S A PROBLEM.

EVA WAS IN THE YUCATAN CENTURIES BEFORE ANYONE WAS MEANT TO HAVE ENTERED NORTH AMERICA.

FOR DECADES, IT'S BEEN ASSUMED THAT THE FIRST AMERICANS ARRIVED FROM SIBERIA, BY FOOT.

DURING THE ICE AGE, SEA LEVELS WERE SO LOW, THERE WAS A LAND BRIDGE WHERE THE BERING STRAITS ARE TODAY.

BUT ONCE PEOPLE ENTERED ALASKA, THEY COULD GO NO FURTHER BECAUSE CANADA WAS COVERED BY TWO GREAT ICE SHEETS, AN UNCROSSABLE BARRIER.

IT WAS ONLY WHEN THE WORLD WARMED AND THE ICE SHEETS STARTED MELTING THAT A ROUTE TO THE SOUTH EMERGED.

IN ALBERTA, THE EVIDENCE OF THAT SOUTHERN ROUTE IS EASY TO FIND-- A SERIES OF GIANT BOULDERS SCATTERED ACROSS THE PLAINS.

THEY'RE KNOWN AS "ERRATICS" BECAUSE THEY DON'T BELONG IN THIS LANDSCAPE.

WOMAN: SO THIS ENORMOUS ROCK SHOULDN'T ACTUALLY BE HERE.

IN FACT, ITS ORIGINAL HOME IS ABOUT 100 MILES NORTH OF HERE, BUT IT GOT TRAPPED BETWEEN THESE TWO ENORMOUS ICE SHEETS, AND IT PUSHED THIS ROCK SOUTH.

AS THOSE ICE SHEETS EVENTUALLY MELTED, IT DEPOSITED THIS ROCK HERE.

ROCKS LIKE THIS ONE, THEY SEEM ISOLATED, BUT WHEN WE ACTUALLY MAP THEM OUT ON THE LANDSCAPE, THEY PROVIDE US AN EXCELLENT IDEA OF WHERE A CORRIDOR WOULD HAVE OPENED UP BETWEEN THESE TWO GIANT ICE SHEETS.

THEY REALLY MARK A PASSAGEWAY INTO NORTH AMERICA.

NARRATOR: ONCE AN ICE-FREE CORRIDOR OPENED, ABOUT 13,000 YEARS AGO, PEOPLE COULD WALK SOUTH INTO WHAT IS NOW THE UNITED STATES.

WAGUESPACK: ON EITHER SIDE OF YOU ARE ENORMOUS ICE SHEETS THAT ARE PULLING APART FROM EACH OTHER AND MELTING.

YOU WOULD HAVE HEARD THE RUSH OF THE MELT WATER.

YOU WOULD HAVE PROBABLY HEARD CRACKING ICE AND LARGE CHUNKS OF ICE BREAKING OFF OF THESE SHEETS.

AS THEY MOVED FURTHER AND FURTHER SOUTH, THEY WOULD HAVE EMERGED INTO A LANDSCAPE THAT NO HUMANS HAD EVER TRODDEN ON BEFORE.

THERE WOULD BE NO SIGNS OF HUMAN LIFE.

THEY WOULD KNOW THAT THEY WERE TRULY THE FIRST PEOPLE TO EXPERIENCE THOSE LANDSCAPES.

NARRATOR: THIS NEW WORLD WAS HOME TO HERDS OF GREAT BEASTS... NONE GREATER THAN THE COLUMBIAN MAMMOTH.

WEIGHING UP TO 9 TONS, IT WAS A BONANZA FOR ANY HUNTER WHO COULD KILL ONE.

[MAMMOTHS GRUNTING] THE FIRST EVIDENCE MAMMOTHS WERE HUNTED BY EARLY AMERICANS TURNED UP IN THE 1930s.

AT A SERIES OF SITES IN THE SOUTHWEST, ARCHAEOLOGISTS FOUND SPEARHEADS ALONGSIDE MAMMOTH BONES.

THESE SPEARHEADS BECAME KNOWN AS "CLOVIS POINTS," AFTER ONE OF THE SITES IN CLOVIS, NEW MEXICO.

EVER SINCE, THEY'VE BEEN DISCOVERED ACROSS THE UNITED STATES.

THEY'RE SO COMMON, ARCHAEOLOGISTS DESCRIBE THE PEOPLE WHO MADE THEM AS CLOVIS PEOPLE.

[BIRDS CHIRPING] [DISTANT OVERLAPPING CHATTER] NARRATOR: THIS ROCK SHELTER IN THE OZARKS IS A NEW ARCHAEOLOGICAL SITE.

EXCAVATIONS HAVE ONLY JUST BEGUN, BUT IT SEEMS CLOVIS PEOPLE USED THE SHELTER AS A CAMPSITE.

13,000 YEARS AGO, A FAMILY GROUP MAY HAVE STAYED HERE A FEW DAYS BEFORE MOVING ON.

LIFE WAS DOMINATED BY FOOD: FINDING IT, PROCESSING AND EATING IT.

HUNTER-GATHERERS ARE SO ACTIVE, THEY CONSUME UP TO 4 TIMES MORE PROTEIN THAN PEOPLE TODAY.

METIN EREN IS ONE OF THE DIRECTORS OF THE ARCHAEOLOGICAL SITE AND AN EXPERT FLINT-KNAPPER.

HE CAN MAKE A CLOVIS POINT AS IT WOULD HAVE BEEN MADE BY EARLY AMERICANS.

[BLOWS 3 TIMES] EREN: THIS IS A CLOVIS POINT, AND IT'S AN AMAZING PIECE OF STONE AGE TECHNOLOGY.

NO ONE IN THE STONE AGE HAD SEEN ANYTHING LIKE THIS BY THE TIME IT WAS MADE OVER 13,000 YEARS AGO.

INCREDIBLY RAZOR-SHARP EDGES ALONG THE ENTIRE BLADE, AND BECAUSE IT'S GOT THESE GROOVES ON BOTH SIDES, IT'S EASILY HAFTED ONTO THE END OF A SPEAR SHAFT, AND THUS IT COULD HAVE ALSO EASILY TAKEN DOWN THE LARGEST STONE AGE BEASTS.

IN A LOT OF WAYS, YOU CAN CONSIDER THIS TO BE THE FIRST AMERICAN INVENTION.

[BLOWS TWICE] EREN: THIS IS A CLOVIS POINT THAT I MADE, AND A CLOVIS PERSON WOULD HAVE HAFTED IT ONTO A PIECE OF WOOD, TO WHICH THEY WOULD HAVE ATTACHED IT TO A LARGE SPEAR LIKE THIS, MADE OUT OF CANE.

THEY COULD HAVE THEN ATTACHED THE SPEAR TO WHAT'S CALLED AN ATLATL, OR SPEAR THROWER.

AND WITH THE SPEAR THROWER, THEY WOULD HAVE HAD JUST A TON OF OOMPH WITH WHICH TO HIT ANY LARGE ICE AGE ANIMALS.

EREN: SO THAT'S DEFINITELY A KILL.

OH, WOW!

THIS CLOVIS POINT WENT ALL THE WAY THROUGH THIS 3-INCH TARGET, SO YOU CAN EASILY IMAGINE THE SORT OF DAMAGE THAT THIS WOULD HAVE DONE, UM, TO THE PREY THAT CLOVIS PEOPLE WERE GOING AFTER.

IT'S AN INCREDIBLE WEAPON.

NARRATOR: BUT HOW DID CLOVIS PEOPLE MANAGE TO BLAZE A TRAIL?

WHERE TO GO, WHAT TO DO IN A VAST, UNKNOWN LAND?

BOB STEVENS IS AN APACHE INDIAN, A HUNTER, A TRACKER, AND AN EXPERT IN SURVIVAL.

STEVENS: BEING OUT HERE IN THE WILD AMONGST THIS LANDSCAPE, I FEEL THE WIND, AND THE WIND BLOWS RIGHT THROUGH ME.

ALL THE SOUNDS BECOME A PART OF ME, BECOME A RHYTHM WITH MY HEARTBEAT.

NOT ONLY DO I BECOME THE WORLD AROUND ME, BUT THE WORLD AROUND ME BECOMES ME, AND WE BECOME ONE.

NARRATOR: CLOVIS PEOPLE HAD NO INSTRUCTION MANUAL, NO ONE TO TELL THEM WHERE TO HUNT.

THEY HAD TO WORK IT OUT FOR THEMSELVES.

STEVENS: THE FIRST THING YOU WOULD DO IS LOOK FOR A HIGH VANTAGE POINT SOMEWHERE.

AND ONCE YOU GET TO A HIGH VANTAGE POINT, THEN YOU CAN SEE MORE OF THE TERRAIN AROUND YOU, AND THE LAND SPEAKS TO YOU.

ALL THE ANIMALS ARE GONNA COME DOWN TO THESE AREAS HERE IN THE BOTTOM OF THE CANYON, AND THEY'RE GONNA NEED PATHWAYS TO COME DOWN TO GET WATER.

THEY'RE GONNA CONCENTRATE IN THIS AREA HERE BECAUSE ANYWHERE UP THE CANYON FROM HERE AND DOWN THE CANYON FROM HERE IS A BOX CANYON; THERE'S NO ACCESS IN OR OUT.

YOU KNOW THEY'RE GONNA COME DOWN TO THIS ONE VERY SPOT.

SO THIS WOULD BE A GOOD, CENTRALIZED LOCATION TO ESTABLISH A LITTLE SEMI-RESIDENCE AND THEN WORK YOUR WAY OUT FROM HERE AND START EXPLORING THE LAND A LITTLE BIT FURTHER OUT.

STEVENS: THE FIRST PEOPLE THAT COME FROM THE LAND BRIDGE UP BY ALASKA, IT'S AMAZING AT THE SPEED THAT THEY COME THROUGH HERE.

PERHAPS IT'S THAT URGE TO EXPLORE.

MAYBE THERE WAS SOMETHING THAT LIE JUST BEYOND THE NEXT RISE, BEYOND THE NEXT HILLSIDE.

SO WHAT I DO WHEN I COME OUT HERE IS I HAVE THAT SAME URGE TO WANT TO KNOW WHAT'S JUST BEYOND THAT LAST HILL THAT I CAN SEE AND TO BE ABLE TO GO OVER THERE, PEEK OVER THE OTHER SIDE, AND SAY, "I KNOW WHAT'S THERE."

AND WHAT DO I SEE?

I SEE ANOTHER HILL.

AND IT KEEPS THAT DRIVE ALIVE TO KEEP ME GOING BEYOND, FURTHER AND FURTHER.

[BLOWS] WAGUESPACK: PART OF THE APPEAL OF THIS STORY IS HOW NICELY IT REFLECTS SOME CLASSIC IDEAS ABOUT THE AMERICAN WEST, THIS IDEA OF RUGGED INDIVIDUALS DRIVEN INTO A NEW LANDSCAPE, ONLY TO SUCCESSFULLY SORT OF CONQUER IT AND COLONIZE IT.

NARRATOR: BUT IS THE STORY REALLY TRUE?

WERE CLOVIS HUNTERS THE FIRST PEOPLE IN AMERICA?

THE OLDEST ARCHAEOLOGICAL EVIDENCE THEY LEFT BEHIND GOES BACK 13,000 YEARS.

BUT IN YUCATAN, EVA WAS ALIVE 13,500 YEARS AGO.

SHE'S HUNDREDS OF YEARS OLDER THAN CLOVIS.

IF EVA AND HER KIND MANAGED TO REACH THE SOUTHEAST OF THE CONTINENT SO EARLY, PEOPLE MUST HAVE ENTERED NORTH AMERICA LONG BEFORE 13,000 YEARS AGO.

SO WHEN DID THEY ARRIVE?

HOW DID THEY GET HERE?

[CATTLE LOWING] JACQUELYN GILL BELIEVES SHE CAN DATE THE ARRIVAL OF PEOPLE IN NORTH AMERICA NOT BY STUDYING BONES OR TOOLS, BUT DUNG.

THERE'S A TYPE OF FUNGAL SPORE KNOWN AS SPORORMIELLA THAT THRIVES IN THE NUTRIENT-RICH DUNG OF LARGE GRASS-EATING ANIMALS.

GILL: THE MORE ANIMALS, THE MORE DUNG.

AND THE MORE DUNG, THE MORE SPORES.

AND WHAT'S SO FANTASTIC ABOUT THESE SPORES IS THAT THEY LAST FOR THOUSANDS OR TENS OF THOUSANDS OF YEARS, SO YOU CAN LITERALLY DIG DOWN INTO THE SOIL AND GO BACK INTO THE PAST TO WORK OUT HOW MANY ANIMALS WERE ON THE LANDSCAPE.

NARRATOR: JACQUELYN GILL TAKES SAMPLES OF MUD FROM ANCIENT LAKE BEDS.

SHE ADDS A SOLVENT AND SPINS THEM IN A CENTRIFUGE TO EXTRACT THE FUNGAL SPORES.

SHE CAN THEN COUNT THE SPORES TO WORK OUT HOW MANY ANIMALS WERE AROUND IN PREHISTORIC TIMES, ANIMALS LIKE MAMMOTH AND MASTODON.

GILL: AFTER MANY HOURS COUNTING THESE SPORES, I NOTICED SOMETHING INTERESTING.

15,000 YEARS AGO, THERE WERE A LOT OF SPORES, WHICH MEANS THERE WERE A LOT OF ANIMALS ON THE LANDSCAPE.

BUT THEN SOMETHING HAPPENED; BY ABOUT 14,800 YEARS AGO, THE NUMBER OF SPORES STARTED TO GO DOWN, AND THEN, BY ABOUT 13,500 YEARS AGO, THEY WERE COMPLETELY GONE.

NARRATOR: THE DISAPPEARANCE OF THESE SPORES SUGGESTS ANIMALS WERE BEING HUNTED LONG BEFORE THE FIRST CLOVIS POINTS.

GILL: BY THE TIME CLOVIS HUNTERS SHOW UP IN NORTH AMERICA, THE LANDSCAPE IS ALREADY PRETTY DEPLETED OF LARGE ANIMALS, WHICH MEANS THAT THERE HAD TO HAVE BEEN PEOPLE HERE MUCH EARLIER THAN WE PREVIOUSLY THOUGHT.

NARRATOR: BUT IF PEOPLE WERE HUNTING ANIMALS BEFORE CLOVIS, WHERE'S THE ARCHAEOLOGICAL EVIDENCE?

THIS IS A RIB BONE, DISCOVERED IN WASHINGTON STATE ON THE OLYMPIC PENINSULA.

IT BELONGS TO A MASTODON, AN ELEPHANT-LIKE SPECIES RELATED TO THE MAMMOTH.

MAN: THE UNIQUE THING ABOUT THIS RIB BONE IS THIS MASS OF BONE EMBEDDED INTO THE RIB ITSELF.

AND WE WONDERED WHAT THIS WAS, SO WE DID HIGH-RESOLUTION CT SCANNING ACROSS THE BONE AND CREATED A 3D MODEL OF WHAT THIS OBJECT LOOKED LIKE.

NARRATOR: THE OBJECT IS CLEARLY MANMADE; NOT A CLOVIS POINT, BUT A MORE BASIC TYPE OF SPEARHEAD THAT'S PENETRATED THE RIB.

WATERS: IT'S A BONE PROJECTILE POINT THAT WOULD HAVE BEEN HURLED AT THIS ELEPHANT.

IT WOULD HAVE THEN PENETRATED THROUGH THE TOUGH HIDE OF THE MASTODON, GONE ABOUT 20, 25 CENTIMETERS INTO THE MASTODON, THROUGH ITS TISSUE, AND THE TIP END JUST FORTUITOUSLY ENDING UP BECOMING EMBEDDED INTO THE RIB OF THIS ANIMAL.

THEN WHAT HAPPENED, AS THE ANIMAL WAS WIGGLING AROUND, THE TIP END BROKE OFF INTO THE RIB ITSELF.

WE DIDN'T KNOW THE AGE PRECISELY, SO WE RADIOCARBON-DATED THE BONE, AND IT CAME OUT 13,800 YEARS AGO.

THIS ANIMAL WAS HUNTED AND KILLED BY HUMANS ALMOST 8 CENTURIES BEFORE CLOVIS APPEARS IN NORTH AMERICA.

8 CENTURIES BEFORE CLOVIS APPEARS IN NORTH AMERICA.

GILL: THERE HAD TO HAVE BEEN PEOPLE HERE MUCH EARLIER THAN WE PREVIOUSLY THOUGHT.

STEVENS: IT'S AMAZING AT THE SPEED THAT THEY COME THROUGH HERE.

NARRATOR: IT'S BECOMING INCREASINGLY CLEAR THE EARLIEST AMERICANS WERE NOT CLOVIS HUNTERS WHO CAME THROUGH THE ICE-FREE CORRIDOR 13,000 YEARS AGO.

THERE HAD TO BE ANOTHER WAY INTO NORTH AMERICA.

JON ERLANDSON BELIEVES THE FIRST AMERICANS CAME BY BOAT AS EARLY AS 16,000 YEARS AGO.

WHILE THE LAND AT THAT TIME WAS STILL BLOCKED BY ICE, THE COAST OF THE PACIFIC NORTHWEST WAS MOSTLY ICE-FREE.

IT WAS POSSIBLE TO FIND A ROUTE SOUTH, BYPASSING ANY ICEBERGS AND LIVING FROM THE BOUNTY OF THE SEA.

ERLANDSON: ONE OF THE REASONS THE COASTAL ROUTE IS SO ATTRACTIVE IS THIS STUFF.

THIS IS BULL KELP, AND IN ONE FORM OR ANOTHER, KELP FORESTS EXTENDED ALL AROUND THE PACIFIC RIM.

THESE KELP FORESTS ARE SUPER-PRODUCTIVE.

THEY PUT OUT BILLIONS OF SPORES, THEY CAN GROW AS MUCH AS A METER A DAY, AND THEY ULTIMATELY SUPPORT VERY COMPLEX FOOD WEBS-- FISH, SHELLFISH, MARINE MAMMALS-- AND ULTIMATELY, IT'S EDIBLE AND QUITE TASTY.

[CRUNCHING] PRETTY GOOD, ACTUALLY.

NARRATOR: RATHER THAN WALKING THROUGH AN ICE-FREE CORRIDOR, THE VERY FIRST AMERICANS COULD HAVE PADDLED DOWN A KELP HIGHWAY.

THERE ARE KELP FORESTS ALONG THE PACIFIC COAST FROM NORTH TO SOUTH AMERICA, ALL THE WAY TO PATAGONIA.

TRAVELING DOWN THE KELP HIGHWAY WOULD HAVE BEEN QUICKER AND EASIER THAN COMING OVER LAND...

ALWAYS GOING THROUGH THE SAME TERRAIN, ALWAYS AT SEA LEVEL.

ERLANDSON: ANTHROPOLOGICAL THEORIES SUGGESTED THAT PEOPLE DIDN'T START REALLY FISHING AND DEVELOP BOATS UNTIL 10,000 YEARS AGO.

IT--IT WAS ALWAYS INEXPLICABLE TO ME.

THE COASTLINES ARE SO PRODUCTIVE.

WHY WOULD HUMANS IGNORE THEM FOR 99% OF HISTORY?

I STILL THINK PEOPLE MAY HAVE COME DOWN THE ICE-FREE CORRIDOR.

I JUST THINK, AT THIS POINT, IT'S MORE LIKELY THEY CAME DOWN THE COAST EARLIER AND THAT THE VERY FIRST AMERICANS WERE COASTALLY ADAPTED.

NARRATOR: ANY ARCHAEOLOGICAL EVIDENCE FOR A COASTAL MIGRATION HAS BEEN WASHED AWAY BY THE RISING SEAS.

BUT ACCORDING TO THIS THEORY, THE PACIFIC SEABOARD WAS DOTTED WITH MAKESHIFT CAMPS.

PEOPLE WOULD HAVE MOVED FROM HEADLAND TO HEADLAND, CATCHING FISH AND MARINE MAMMALS AND HARVESTING KELP.

THEN THEY WOULD MOVE ON, ALWAYS HUGGING THE COAST, STAYING IN SIGHT OF LAND.

ERLANDSON: IT MUST HAVE BEEN A TRULY AMAZING JOURNEY TO COME DOWN THE COAST AND EXPLORE THESE PLACES WHERE HUMANS HAD NEVER BEEN BEFORE.

NARRATOR: THESE SEAFARERS MAY THEN HAVE HEADED INLAND...

FOLLOWING ANY LARGE RIVER THEY CAME ACROSS.

IN THIS WAY, THEY COULD HAVE NAVIGATED INTO THE HEART OF THE CONTINENT.

ERLANDSON: FOR PEOPLE MOVING DOWN THE COAST, THESE RIVERS WOULD HAVE BEEN LIKE DETOURS ON THE KELP HIGHWAY.

IT WOULD HAVE PROVIDED ALL THE RESOURCES THAT COASTAL PEOPLES NEEDED TO EXPLORE DEEP INTO THE INTERIOR AND ULTIMATELY COLONIZE ALL OF NORTH AMERICA.

NARRATOR: THE U.S. RIVER SYSTEM PROVIDES A POTENTIAL MAP OF THEIR JOURNEY.

IF THEY CAME INLAND ALONG THE COLUMBIA RIVER, THEY COULD HAVE JOINED UP WITH THE MISSOURI, WHICH FLOWS INTO THE MISSISSIPPI, AND FINALLY INTO THE GULF OF MEXICO.

IN THIS WAY, PEOPLE LIKE EVA COULD HAVE CROSSED THE CONTINENT LONG BEFORE THE ICE-FREE CORRIDOR OPENED UP.

[BLOWS] BUT IF PEOPLE CAME ALONG THE COAST AND THEN THE RIVERS, WHERE ARE THEIR REMAINS?

WHO WERE THEY AND WHAT BECAME OF THEM?

ONE OF THE MOST COMPLETE PREHISTORIC SKELETONS IN NORTH AMERICA IS KEPT IN THIS MUSEUM.

IT IS OF A MAN WHO MAY HAVE BEEN AN EARLY COASTAL MIGRANT, TRAVELING THE KELP HIGHWAY.

BUT IT'S IMPOSSIBLE TO FILM HIS BONES BECAUSE THEY'RE A SECURITY RISK.

MAN: THERE IS SEVERAL LAYERS OF, UH, LOCKED AND ALARMED DOORS AND SECURITY CAMERAS AND THAT SORT OF THING.

AND THIS PARTICULAR SKELETON IS TWO LAYERS DEEPER INTO ITS OWN SECURITY SYSTEM.

IT'S THE VAULT INSIDE THE BANK, UM, INSIDE THE SECURE CITY, I WOULD SAY.

IT WOULD BE VERY, VERY DIFFICULT TO BREAK IN AND GET THE REMAINS.

NARRATOR: THE SKELETON WAS DISCOVERED IN 1996.

IT'S A MAN WHO WAS BURIED OVER 8,500 YEARS AGO BESIDE THE COLUMBIA RIVER NEAR KENNEWICK, WASHINGTON.

HE HAS BECOME KNOWN AS "KENNEWICK MAN."

BUT RIGHT AWAY, LOCAL TRIBES WANTED HIM REBURIED.

[WIND CHIMES TINKLE] NATIVE AMERICANS HAVE A FEDERAL RIGHT OF RETURN ON ANCIENT REMAINS.

[MEN SINGING IN NATIVE LANGUAGE] NARRATOR: IF THEY CAN PROVE AN ANCESTRAL LINK, THE AUTHORITIES ARE MEANT TO HAND OVER ANY BONES FOR REBURIAL, A PROCESS KNOWN AS REPATRIATION.

[SINGING CONTINUES] NARRATOR: BUT WITH KENNEWICK MAN IT HAS NEVER HAPPENED...

DESPITE THE EFFORTS OF TRIBAL LEADERS LIKE ARMAND MINTHORN.

MINTHORN: OUR WAY OF LIFE IS DIFFERENT.

WE HAVE UNWRITTEN LAWS THAT WE PASS GENERATION TO GENERATION.

BUT IN THE MEANTIME, WE HAVE TO FOLLOW THE LETTER OF THE LAW.

WE WORKED WITH THE FEDERAL AGENCY.

WE WERE READY FOR REPATRIATION, AND THEN THAT'S WHEN THE SCIENTISTS STEPPED IN, AND THEY WANTED TO DO STUDIES, AND THEN THIS IS WHERE IT WENT TO COURT.

NARRATOR: ANTHROPOLOGISTS BELIEVE THE FOSSIL IS TOO IMPORTANT AND INTRIGUING TO BE REBURIED.

THEY TOOK OUT A LAWSUIT TO STOP THE REPATRIATION.

EVER SINCE, KENNEWICK MAN HAS BEEN IN A STATE OF LIMBO... HIS FATE UNDECIDED, HIDDEN FROM VIEW.

IN 2004, THE COURTS ALLOWED THE BONES TO BE SCRUTINIZED BY DOUG OWSLEY.

BASED AT THE SMITHSONIAN, HE IS ONE OF THE WORLD'S LEADING FORENSIC ANTHROPOLOGISTS.

HIS TEAM WAS GIVEN TWO WEEKS WITH THE BODY TO DO A DEFINITIVE EXAMINATION.

THEY GENERATED SO MUCH DATA, IT TOOK 9 YEARS TO PUBLISH THE RESULTS.

WHEN WE SUMMARIZE KENNEWICK MAN, FOR ONE THING, WE'D SAY HE'S ABOUT 160 POUNDS, HE'S 5'7 1/2".

HE'S ABOUT 40 YEARS OF AGE.

[DISTANT DOG BARKS] HE'S A VERY STURDY MAN.

HE'S VERY STRONG.

HE HAS VERY ROBUST BONES, HE'S VERY WIDE-BODIED.

HE HAS A MUCH LARGER, MUCH STRONGER RIGHT ARM THAN LEFT.

WE LINK THAT UP TO THE USE OF AN ATLATL.

THAT'S A VERY QUICK, RAPID MOTION.

AS YOU DO THIS, YOU'VE GOT TO CATCH YOURSELF, SO YOU'LL THROW YOUR LEFT LEG FORWARD, AND THAT'S GOING TO BE THE ONE THAT'LL CATCH YOU.

AND IT'S AMAZING, BUT YOU CAN ACTUALLY SEE A DIFFERENCE IN THE STRENGTH OF THE LEFT LEG VERSUS THE RIGHT LEG.

NARRATOR: BUT THE SAME WEAPONS-- A SPEAR AND ATLATL-- SEEM TO HAVE BEEN USED AGAINST KENNEWICK MAN.

WHEN YOU LOOK AT HIS PELVIS, HIS RIGHT HIP BONE HAS AN EMBEDDED SPEAR POINT.

[YELLS] OWSLEY: IT WOULD HAVE JUST KNOCKED HIM DOWN HARD.

[GROANING] AAH!

OWSLEY: IT SLICED INTO THE RIGHT PELVIC BONE.

IT SHEARED OFF PART OF THE PELVIC CREST, BUT AS FAR AS BEING A LUCKY SHOT, IT REALLY WAS BECAUSE IF IT HAD GONE JUST A LITTLE BIT MORE IN, IT WOULD HAVE GONE INTO THE INTERNAL ORGANS, CERTAINLY WOULD HAVE KILLED HIM.

[GROANING] NARRATOR: HE ALSO HAD 5 BROKEN RIBS.

AAH!

HE MAY HAVE GOT THEM AT THE SAME TIME AS THE SPEAR.

OWSLEY: THE TYPE OF INJURY THAT YOU SEE IN THE RIBS, IT'S THE KIND OF THING THAT I SEE IN MY FORENSIC CASE IDENTIFICATION WHEN SOMEBODY KICKS SOMEBODY.

[GRUNTS] WHOEVER THE ASSAILANT WAS COULD HAVE BEEN CLOSE ENOUGH TO HIM TO ACTUALLY BE ABLE TO GIVE HIM A GOOD STOMP AND THEN BREAK THESE RIBS.

BUT HE WAS JUST TOUGH AS NAILS AND SURVIVED.

AAH!

HE WAS ABLE TO GET AWAY, AND HE LIVED A GOOD 20 YEARS AFTER THIS HAPPENED.

NARRATOR: WHAT MORE CAN THE BONES OF KENNEWICK MAN REVEAL?

OWSLEY HAS ANALYZED THEIR CHEMICAL CONTENT, THEIR ISOTOPE SIGNAL.

THIS CAN SHOW WHAT KENNEWICK MAN ATE AND WHERE HIS FOOD CAME FROM.

OWSLEY: WHEN WE RUN HIS ISOTOPE SIGNAL, HE'S GOT A MARINE SIGNATURE, AND THE FIRST THING YOU'D THINK OF IS THERE'S LOTS OF SALMON GOING UP AND DOWN THE-- THE COLUMBIA RIVER DRAINAGES.

AND THIS FELLOW'S FOUND ALONG THE COLUMBIA RIVER; YOU'D THINK THAT'S A NATURAL THING.

NARRATOR: BUT SOME OF THE CARBON LEVELS ARE SO HIGH, THEY CANNOT HAVE COME FROM EATING ANY AMOUNT OF RIVER FISH.

INSTEAD, KENNEWICK MAN SEEMS TO HAVE LIVED ON A DIET OF MARINE MAMMALS.

OWSLEY: THIS MAN IS COMING, ACTUALLY, FROM A COAST, AND HE'S HEAVILY DEPENDENT, IN TERMS OF HIS ISOTOPE SIGNAL-- READING HIS ISOTOPE SIGNAL, HE'S HEAVILY DEPENDENT ON SEALS.

HE IS COMING FROM AS FAR NORTH AS CENTRAL ALASKA.

NARRATOR: ACCORDING TO THE FORENSIC EVIDENCE, KENNEWICK MAN HAD A LIFESTYLE SIMILAR TO OTHER EARLY COASTAL MIGRANTS, FEEDING HIMSELF FROM THE SEA.

HE WOULD ONLY HAVE HEADED INLAND TO THE COLUMBIA RIVER LATER IN LIFE.

OWSLEY: AND THAT SURPRISES THE DICKENS OUT OF ME.

I WOULD HAVE NEVER PREDICTED THAT.

ANYBODY THAT LOOKED AT THIS WOULD THINK THIS IS HIS HOME.

IT IS NOT HIS HOME.

HE'S NOT FROM THERE.

NARRATOR: NATIVE AMERICANS REJECT THIS IDEA.

THEY CALL HIM "THE ANCIENT ONE" AND BELIEVE HE WAS ONE OF THEIR OWN.

HIS BURIAL AT THE COLUMBIA RIVER SUGGESTS HE WAS NOT A LONE TRAVELER, BUT PART OF AN ESTABLISHED COMMUNITY.

MINTHORN: WE BELIEVE THE ANCIENT ONE LIVED SIMILAR TO HOW WE LIVE TODAY, AS FAR AS EATING THE SAME KINDS OF FOODS, SPEAKING THE SAME LANGUAGE, FISHING FROM THE SAME RIVER.

AND MORE THAN LIKELY, HE WAS BURIED WITH CEREMONY, THERE WERE OTHER PEOPLE.

THEY TOOK CARE OF HIM, AND THEY PUT HIM IN THE GROUND, JUST LIKE WE DO TODAY.

[FLAMES CRACKLING] MINTHORN: US, AS INDIAN PEOPLE, BELIEVE THAT WHEN OUR BODY GOES TO THE GROUND, THAT'S WHERE IT'S TO STAY UNTIL THE END OF TIME.

THAT'S WHAT WE BELIEVE.

AND EVEN IF IT'S 9,000 YEARS AGO, IT DOESN'T MATTER.

WHEN A BODY IS TAKEN OUT OF THE GROUND, LIKE THE ANCIENT ONE, THEIR JOURNEY IS INTERRUPTED.

IT'S STOPPED.

[PEOPLE SINGING IN NATIVE LANGUAGE] NARRATOR: TO PREVENT ANY FURTHER EXCAVATIONS, FEDERAL AUTHORITIES COVERED UP THE GRAVESITE AT THE COLUMBIA RIVER WITH RUBBLE...

BUT THEY'VE NOT YET RETURNED ANY BONES.

TRIBAL GROUPS CLAIM THAT KENNEWICK MAN IS THEIR ANCESTOR.

MINTHORN: AND THE SCIENTISTS CANNOT ACCEPT THE FACT THAT JUST BECAUSE IT'S NOT WRITTEN DOWN IN A BOOK, IT'S NOT FACT.

IT'S FACT TO ME BECAUSE I LIVE IT EVERY DAY.

NARRATOR: DOUG OWSLEY DISAGREES.

HE THINKS THERE'S NO ANCESTRAL LINK BETWEEN MODERN-DAY NATIVE AMERICANS AND KENNEWICK MAN.

THEIR SKULLS ARE THE WRONG SHAPE.

OWSLEY: THIS IS A SKULL OF A NATIVE AMERICAN, AND IT HAS VERY BROAD CHEEKS, AND YOU COMBINE THAT WITH A FAIRLY SHORT, BROAD CRANIUM.

IT'S VERY DIFFERENT FROM WHAT WE SEE IN THESE SKULLS LIKE KENNEWICK MAN.

KENNEWICK MAN, INSTEAD OF BEING A SHORT, BROAD CRANIUM, TENDS TO BE MUCH LONGER AND NARROWER.

AND WHEN YOU LOOK AT HIS FACE, THE WIDTH OF HIS FACE HERE, IT'S JUST NOT QUITE AS HEAVILY BUILT AS WHAT WE SEE IN MODERN-DAY NATIVE AMERICANS.

AND WE CAN ASK, FOR INSTANCE, WELL, WHO IS KENNEWICK MAN MOST LIKE?

WHO IN THE WORLD DOES HE FIT WITH?

WHEN WE DO THAT, WHEN WE ASK THOSE QUESTIONS, WHAT WE SEE IS THAT, ON A WORLDWIDE BASIS, THIS IS WHAT WE SEE IN POLYNESIANS.

NARRATOR: THE FACIAL RECONSTRUCTION OF KENNEWICK MAN IS MODELED ON POLYNESIAN-LOOKING PEOPLE KNOWN AS THE AINU.

THEY ARE TRADITIONAL HUNTER-GATHERERS FROM NORTHERN JAPAN, WHO WERE ALL BUT WIPED OUT IN THE 20th CENTURY.

THEIR SKULLS WERE LONG AND NARROW, SIMILAR TO THAT OF KENNEWICK MAN.

OWSLEY: BUT YOU HAVE TO REALIZE I'M NOT SAYING HE'S POLYNESIAN.

WHAT WE'RE SAYING INSTEAD IS THAT 10,000 YEARS AGO, 15,000 YEARS AGO, THIS IS WHAT PEOPLE LOOKED LIKE IN THE COASTAL ASIA, MARITIME--THESE ARE MARITIME HUNTER-GATHERERS, AND THIS IS WHAT PEOPLE LOOKED LIKE.

NARRATOR: THE SKELETONS FROM YUCATAN ARE THE SAME.

EVA'S SKULL IS LONG AND NARROW, LIKE KENNEWICK MAN.

SHE'S NOT A MATCH WITH MODERN-DAY NATIVE AMERICANS.

ACCORDING TO THIS THEORY, THE FIRST WAVE OF MIGRANTS INTO THE AMERICAS WERE THOSE PEOPLE LIKE KENNEWICK MAN AND EVA, WITH LONG, NARROW SKULLS.

BUT AROUND 8,000 YEARS AGO, ANOTHER WAVE MUST HAVE SWEPT IN-- PEOPLE WITH WIDE, ROUND SKULLS.

THEY WIPED OUT THE FIRST WAVE AND WENT ON TO POPULATE THE AMERICAS.

IF TRUE, THEN TODAY'S NATIVE AMERICANS ARE NOT DIRECTLY RELATED TO KENNEWICK MAN AND HAVE NO CLAIM ON HIS BONES.

BUT THERE IS A SURE-FIRE WAY TO TEST ANCESTRY...

USING DNA.

THE BONES OF KENNEWICK MAN WERE THOUGHT TO BE TOO DEGRADED TO PROVIDE ANY GENETIC DATA.

BUT ESKE WILLERSLEV IS A PIONEER IN THE FIELD OF ANCIENT GENOMICS.

HIS TEAM HAS MANAGED TO EXTRACT SOME USABLE DNA, WHICH COULD PROVE WHETHER OR NOT KENNEWICK MAN WAS RELATED TO TODAY'S NATIVE AMERICANS.

WILLERSLEV: AS A SCIENTIST, IT'S SUPER-EXCITING IF THERE IS A CONTROVERSY BECAUSE THAT MEANS THAT THE RESULT--IF THAT CAN SOLVE THAT CONTROVERSY, THE RESULT MATTERS, RIGHT?

IT MEANS SOMETHING.

IT'S IMPORTANT.

NARRATOR: ONCE THEY HAVE THE DNA, THEY MAKE MILLIONS OF COPIES AND FEED THEM INTO A HIGH-THROUGHPUT SEQUENCING MACHINE.

BY BATHING THEM IN DYES, THE MACHINE SETS OFF A SERIES OF CHEMICAL REACTIONS.

CONSTELLATIONS OF LIGHT FROM ACROSS THE GENOME CAN BE PHOTOGRAPHED AND ANALYZED IN FANTASTIC DETAIL.

WILLERSLEV: I MEAN, I AM, OF COURSE, A GENETICIST, SO I AM BIASED BUT--BUT I REALLY DO THINK THAT--THAT GENETICS, UH, TODAY--ESPECIALLY GENOMICS, AS WE ARE UNDERTAKING HERE-- IS A VERY, VERY POWERFUL TOOL TO ADDRESS THESE KIND OF QUESTIONS OF ANCESTRY.

NARRATOR: WILLERSLEV HAS INVITED ARMAND MINTHORN AND OTHER TRIBAL LEADERS TO VISIT HIS LABORATORY AND FIND OUT THE LATEST ABOUT THE SEQUENCING OF KENNEWICK MAN.

BUT FIRST, HE TAKES THEM TO THE CLEAN ROOM TO SHOW THEM HOW DNA IS EXTRACTED FROM ANCIENT REMAINS.

TODAY, THEY'RE WORKING WITH A 500-YEAR OLD TOOTH OF A VIKING.

[ELECTRIC SAW WHIRRING] NARRATOR: THIS MEETING OF SCIENCE AND TRADITION ENDS WITH A PRAYER.

MINTHORN: WE'RE ALWAYS THINKING OF THE ANCIENT ONE, WHEREVER HE MAY BE, WHATEVER... WILLERSLEV: WHEN I SAW HOW MUCH IT MEANT TO THEM, I ACTUALLY GOT REALLY EMOTIONAL ABOUT IT.

I'M SURE THEY ARE FEELING THAT THEY'RE MAKING A SACRIFICE, EVEN WITH ME TAKING SAMPLES OF THE KENNEWICK MAN, BUT IT'S A SACRIFICE THAT NEEDS TO BE DONE FOR THEM TO POTENTIALLY GET THE REMAINS BACK.

BASICALLY, WHAT I HAVE IN THIS TUBE HERE... NARRATOR: WHATEVER DOUBTS THEY HAVE ABOUT GENETIC RESEARCH, THE TRIBES ARE ABOUT TO GET SOME GOOD NEWS.

WILLERSLEV: THIS IS THE DNA OF THE ANCIENT ONE, AND WE HAVE SEQUENCED PARTS OF THE GENOME ALREADY.

AND BASED ON THOSE ANALYSES OF THAT PART, THAT'S WHERE WE CAN SEE THAT THE ANCIENT ONE IS CLOSER RELATED TO CONTEMPORARY NATIVE AMERICAN PEOPLE THAN TO ANY OTHER PEOPLES IN THE WORLD.

AND I THINK THIS IS REALLY IMPORTANT IN REGARD TO WHAT HAS BEEN CLAIMED ABOUT THE ANCIENT ONE BECAUSE THERE HAS BEEN CLAIM THAT THE ANCIENT ONE, YOU KNOW, IS SOMETHING DIFFERENT THAN PRESENT-DAY NATIVE AMERICANS, RIGHT?

AND IF THAT WAS THE CASE, IF THAT WAS REALLY THE CASE, THEN THE DNA OF THE ANCIENT ONE SHOULD GROUP WITH OTHER PEOPLES IN THE WORLD--FOR EXAMPLE, WITH OTHER ASIAN GROUPS OR SOMETHING LIKE THAT-- AND THAT'S NOT THE CASE.

OK, HE'S BASICALLY FALLING SPOT-ON INTO NATIVE AMERICANS.

IT'S REALLY ENCOURAGING TO... TO HEAR YOU SAY THAT.

US, AS INDIAN PEOPLE, WE'VE ALWAYS KNOWN THAT, AND IT ONLY CONFIRMS AND RECONFIRMS WHAT WE'VE SAID ALL ALONG.

WILLERSLEV: IF ANY OF THIS STUFF WE FIND OUT CAN BE OF HELP TO YOU IN TERMS OF, UH, GETTING THE ANCIENT ONE BACK, I'LL BE HAPPY TO DO WHAT I CAN, YOU KNOW, AND ALSO GO OUT THERE TO THE COURT OR WHATEVER AND--AND ARGUE FOR THE RELIABILITY, ET CETERA, OF THE RESULTS.

OK. NARRATOR: THE DNA COULD BE A GAME-CHANGER.

ONCE KENNEWICK MAN'S GENETIC SEQUENCE IS COMPLETE, IT WILL BE NEW EVIDENCE IN THE CAMPAIGN FOR HIS REPATRIATION.

IF THE GENETICS IS RIGHT, THERE WEREN'T TWO SEPARATE WAVES OF MIGRATION INTO THE AMERICAS, JUST ONE.

EVA, THE CLOVIS PEOPLE, KENNEWICK MAN-- THEY'RE ALL FROM THE SAME GENE POOL AS MODERN-DAY NATIVE AMERICANS.

THEY ARE ALL ONE PEOPLE.

TODAY'S NATIVE AMERICANS MAY LOOK DIFFERENT TO THEIR ANCESTORS, BUT THAT'S NOT UNUSUAL.

AROUND THE WORLD, ALMOST EVERYONE LOOKS DIFFERENT FROM THEIR PREHISTORIC FOREBEARS.

NONE OF US ARE THE PEOPLE WE ONCE WERE.

JOHN HAWKS HAS STUDIED THE WAY HUMAN BIOLOGY HAS CHANGED OVER THE LAST 10,000 YEARS.

HAWKS: THE FIRST PEOPLES FASCINATE US, WHICH IS NATURAL BECAUSE THEY ARE US-- ANCESTORS OF EVERYBODY TODAY.

BUT WE'VE COME TO REALIZE THAT WHEN WE LOOK AT THEIR SKULLS, THEIR FACES, THEY'RE NOT OUR FACES.

WE'VE CHANGED.

THE OBVIOUS QUESTION IS WHY?

NARRATOR: HAWKS BELIEVES THAT HUMANS ARE ACUTELY RESPONSIVE TO CHANGES IN LIFESTYLE.

ONCE WE STOPPED HUNTING AND GATHERING, WE STARTED EATING DIFFERENT FOODS.

THAT ALONE WAS ENOUGH TO CHANGE THE SHAPE OF OUR SKULLS.

AND LIVING IN CITIES, OUR BRAINS AREN'T HAVING TO WORK SO HARD; WE RELY ON THE INTELLIGENCE OF OTHERS.

HAWKS: IT MAY BE SURPRISING, BUT WHEN WE STARTED TO SETTLE DOWN, OUR SKULLS NOT ONLY CHANGED IN SHAPE, THEY BEGAN TO SHRINK.

PRESUMABLY, OUR BRAINS SHRANK AS WELL.

THE FIRST PEOPLES, THEY LIVED IN VERY TINY GROUPS.

ANYTHING THAT THEY WANTED TO MAKE, THEY HAD TO KNOW HOW TO MAKE IT.

ANY FOOD THAT THEY NEEDED TO FIND, THEY NEEDED TO KNOW WHERE IT WAS IN THEIR ENVIRONMENT.

THE KNOWLEDGE ACCUMULATED OVER GENERATIONS, THEY HAD TO HAVE IT ALL RIGHT HERE.

[BLOWS] NARRATOR: LIVING BY THEIR WITS, THESE PIONEERS OPENED UP A NEW WORLD.

WHETHER THEY CAME BY SEA OR BY LAND, WE NOW KNOW THEY ARRIVED AT LEAST 2,000 YEARS EARLIER THAN PREVIOUSLY THOUGHT AND POPULATED THE AMERICAS AT BREAKNECK SPEED.

THE SAME SPIRIT OF EXPLORATION WAS SHARED BY OTHER FIRST PEOPLES OF THE WORLD.

GENETICISTS BELIEVE THEY WERE AS DRIVEN BY THEIR GENES TO TAKE RISKS, EMBRACE CHANGE, AND SEEK OUT WHAT'S NEW.

SOME HAVE CALLED THESE "EXPLORER GENES" AND THEY'RE STILL IN OUR DNA TODAY.

HAWKS: THE FIRST PEOPLES WERE EXPLORERS.

THEY WERE BLAZING TRAILS.

THEY CREATED THE WORLD THAT--THAT WE'RE NOW LIVING IN, AND THAT GENETIC LINK BETWEEN US AND THEM IS WHAT HAS COME DOWN THROUGH THE YEARS, CONNECTING US TO THEM AND PUSHING US OUT TO WHERE WE HAVEN'T BEEN BEFORE.

NARRATOR: NO OTHER SPECIES DOES WHAT WE DO-- MOVE, EXPLORE, AND INHABIT EVERY CORNER OF THE GLOBE.

AND WE DO IT BECAUSE THEY DID IT-- OUR ANCESTORS, THE FIRST PEOPLES.

"FIRST PEOPLES" IS AVAILABLE ON DVD.

TO ORDER, VISIT SHOPPBS.ORG OR CALL 1-800-PLAY-PBS.