Tonight, the most elusive beast in North America.
Bigfoot might be the most widely spotted cryptid in history.
LYNNE MCNEILL: This is not something that's limited
to just one region, or even just one continent.
This is something that is reported all over the world.
Despite thousands of sightings, this mysterious animal
remains unidentified.
FORREST BURGESS: Top scientists are at a loss.
They can't find any match to any known species.
Now, we explore the top theories
surrounding this cryptic creature.
RYAN GOLEMBESKE: How did these two cowboys
pull off the greatest thing in creature feature history?
CHRISTOPHER BADER: It is possible
that some of these could be wild humans.
LYNNE: There was a creature that was thought to have gone extinct
that did match this description.
LAURENCE: Does Bigfoot exist?
And if so, what is it, and where is it?
[music]
September 1958, Humboldt County, California,
lumber worker Jerry Crew is operating a bulldozer
when he spots something strange in the woods.
Maybe 20 feet away from where
he's working, he sees these
large human-like footprints pressed deep into the mud.
And he mentions it to his supervisor,
a man named Wilbur Shorty Wallace.
LAURENCE: Upon closer examination,
the prints are 16 inches across,
much too big to be human.
It's unlike anything he's ever seen before.
Could it be an animal print? Sure.
But if it is, it's strangely human,
but much larger.
LAURENCE: Initially, Jerry suspects a coworker
is playing a prank on him.
RYAN: Let's be real, you're working in a remote area
with a bunch of guys, it's a brotherhood.
We play pranks on each other, it's just what we do.
Shorty Wallace's brother Ray Wallace
is a complete prankster.
So, when Jerry sees these prints,
he's assuming that the guys are pulling his leg.
LAURENCE: But soon, other strange accounts surface.
LYNNE: At a job site the year before,
a 450-pound fuel drum
went missing.
It was found nearby in a gully,
but it had these giant human-like footprints nearby.
This is not something that an average-sized human being
could move on their own at all.
People also see a 700-pound tire
is magically moved over to a ditch.
And what is around it? Tracks.
LAURENCE: Given the size of the footprints,
the loggers come up with a nickname for the creature--
Bigfoot.
FORREST: There are lots of logging operations in the area,
and workers on other sites catch wind of this Bigfoot.
For many of them, this strikes a chord.
LYNNE: A number of them who have been working
out in these woods have reported the sensation
of feeling like they've been watched,
that there is some sort of intelligence
that is observing them as they work.
LAURENCE: It's not long before these accounts
attract local media attention.
FORREST: The story of Bigfoot makes its way
to the Humboldt Times newspaper in the form of a letter
that lands on the desk of writer Andrew Genzoli.
Like Jerry Crew, Genzoli assumes at first
that the letter is from some crackpot.
But on September 21st, 1958, he has a column to finish,
so he mentions it towards the end
just as a bit of a joke, like, "Hey, guess what,
"Humboldt County has its very own abominable snowman.
They call it Bigfoot."
Once people see this story, it catches on like wildfire.
People are intrigued by this.
It ties in with their own experiences.
They've heard rumors that fall right into line
with what's being reported.
It only makes sense at this point
that Genzoli is going to follow up.
So, he sets out to follow up with Crew
to talk to the other lumberjacks
to find out what's going on here.
What Genzoli ultimately found out
when he did some more research
is that the idea of Bigfoot itself,
of a large creature with large footprints,
was not new, and in fact, was part of the folklore
of Native American tribes for some time.
There are reports of unusual footprints
and sightings here dating back throughout the 1800s.
RYAN: In 1850, a prospector was mining
on the side of Mount Shasta,
and he had what could be said as one of the first interactions
with Bigfoot, when a large hairy hominid
came out of the woods and smashed his sluice,
and then went back in the woods, as if to say,
"Get the hell off my mountain."
Because of all of the stories coming in,
all of the engagement from readership,
the Humboldt Times ends up publishing an entire series
of stories about this creature called Bigfoot.
This causes a huge stir, and this story goes national.
LAURENCE: Within weeks, the name "Bigfoot"
is known across America.
RYAN: With all this attention,
there is a mad rush to investigate.
And so, the L.A. Times, the New York Times,
they all show up because they want a piece of Bigfoot.
The whole country is buzzing about this.
We see an immediate divide between believers
and non-believers, and skeptics and die-hards.
Everyone has an opinion.
A popular TV show offers a $1,000 prize
to anyone who will come forward
and admit to perpetrating this hoax.
And no one steps up to claim the money.
LAURENCE: In fact, new evidence emerges.
RYAN: So, on October 17th, 1958,
a gentleman named George Smith
is driving through Humboldt County,
and he has to slam on his brakes as this large hairy beast
crosses the road in front of him.
JEFF MELDRUM: He described it as being
at least eight feet in height.
It stood upright and walked,
and it appeared shaggy
like it was wearing a bearskin coat.
FORREST: Could this be the same beast
that's been leaving behind all these footprints?
Or is Smith just making this story up
to get his 15 minutes of fame?
Despite the fact that we don't end up with any proof
either way, Bigfoot becomes engrained
in our nation's collective psyche.
People are actually making trips,
making pilgrimages-- what folklorists
would call legend trips to Humboldt County
to look for Bigfoot themselves.
For years, unsubstantiated reports of sightings
continue pretty regularly.
More oversized Bigfoot tracks are found,
some trails stretching on for several miles.
LYNNE: This is not something that's limited
to just one region or even just one continent.
This is something that is reported
in firsthand and secondhand accounts
all over the world.
But as time goes on, the mystery begins to take on
a slightly different tone.
LAURENCE: Tales of Bigfoot encounters
grow more outlandish and increasingly suspicious.
CHRISTOPHER: People started to claim everything
from Bigfoot kidnapped them,
to they've seen Bigfoot reading a newspaper
on a flying saucer.
They saw Bigfoot at 7-Eleven.
FORREST: The vast majority of these later Bigfoot stories
are clearly made up.
Bigfoot almost becomes a joke.
People do not take this seriously.
This is not treated as a scientific finding.
It's something that's largely considered to be untrue.
It's a shame, really, because there are people
who really saw something, and they really want answers.
There are proven scientific methods
that could possibly find those answers.
Once everybody thinks Bigfoot is made up though,
they stop taking the search seriously.
Still, it's worth pointing out, as silly as things get,
that original Humboldt Times story from 1958
is never officially debunked.
LAURENCE: That is, until 2002.
In November of 2002,
Jerry Crew's coworker Ray Wallace passed away.
Soon after his death, Wallace's children come forward
to reveal their father orchestrated the whole thing
back in the 1950s and kept quiet about it
all these years.
LAURENCE: On his deathbed, Wallace has told his children
the whole story.
Ray Wallace comes up with the idea,
and he enlists the help of his brother Shorty, obviously.
And then they also get their nephew
Mack McKinley in on it as well.
CHRISTOPHER: He and his brother and his nephew
would strap essentially wooden flip flops
onto their feet and walk around,
creating these large footprints.
Wallace's kids even have a pair of the shoes
their dad used to make the famous footprints.
CHRISTOPHER: Wallace was a prankster,
and according to his children, his original goal
was simply to scare his friend Jerry.
FORREST: But when the story blows up,
rather than enjoying his "gotcha" moment,
he decides to double down
and keep the ruse going for decades.
LAURENCE: Wallace's efforts aren't limited
to fake footprints.
On his property, Ray Wallace keeps a number of bison,
and he uses their fur and their droppings
to custom craft hair and stool samples
that he leaves in the woods for Bigfoot hunters to find.
Based on Wallace's hoax confirmation,
for a lot of people, that's it.
It should be case closed, we figured it out,
this guy made something up.
LAURENCE: But what about the other sightings?
It is impossible for Ray, and Shorty, and Mack
to be responsible for all Bigfoot sightings,
experiences, interactions in the entire world.
And Wallace never dressed up as an eight-foot-tall creature
and walked around at night.
What does that say for people who actually spotted an animal,
and not just footprints or hair?
And what about the many sightings
that take place before Wallace is ever born?
Has there been a century-long series of hoaxers,
or are people really seeing something out there?
CHRISTOPHER: While Wallace clearly played an important role
in the gestation of the Bigfoot myth,
he is certainly not the cause of it
or the entire explanation for it.
RYAN: There have been over 5,000 documented sightings.
There's no way one guy
could be responsible for all of that.
FORREST: I believe Ray Wallace accidentally shined a light
onto a legend of a very real creature.
The irony is that Ray Wallace's fake footprints
may ultimately lead us to the truth.
LAURENCE: 1967, Bluff Creek, California,
11 years after news spreads nationwide
of a creature called Bigfoot,
two outdoorsmen head off to hunt the beast
along the Klamath River.
FORREST: In the summer of 1967,
Roger Patterson, who's become fascinated
with the legend of Bigfoot, is filming
a sort of pseudo-documentary
on the subject, when he bumps
into his old friend Bob Gimlin
at a gas station.
He tells Gimlin about his film,
and that he's heading to check out
some unidentified footprints
found in the Northern California area.
Gimlin agrees to go with him.
LYNNE: So, Patterson and Gimlin
are about halfway through their journey
when they're approaching a river,
and something spooks
Patterson's horse.
He ends up falling off the horse,
but when he sees what it was that his horse saw,
he pulls out his camera and begins filming.
The filmed encounter lasts 59 1/2 seconds.
To Patterson and Gimlin, it feels like an hour.
Something emerges from the brush--
an enormous animal Patterson and Gimlin
have never seen before.
They think it might be Bigfoot.
CHRISTOPHER: Once they surprise the creature, it starts walking
quickly away from them,
and they manage to follow it for quite some time
before they lost sight of it in the woods.
Patterson and Gimlin then hurry back to their campsite
to grab some plaster.
They know they're going to need as much proof as possible,
so they take casts of the prints left behind by the beast.
LAURENCE: That night, the 16-millimeter film
is developed.
LYNNE: What the film shows us
is a massive bipedal creature.
It's maybe six and a half, seven feet tall.
It's covered head to toe
in this sort of silvery brown fur
that reflects the sunlight, and it's walking
with this loping sort of gait through the landscape.
FORREST: Compared to previous descriptions,
it's slightly smaller, with wider hips
and a rounder silhouette.
It also appears to have mammary glands.
Gimlin and Patterson theorize
that they're looking at a female Bigfoot.
They nickname her Patty, after Roger Patterson.
LAURENCE: Though the pair are convinced by what they saw,
many dismiss the film as a hoax.
RYAN: The Patterson-Gimlin footage has been scrutinized
since it came out.
Everyone's had a chance to look at it,
try to break it down, try to explain
why it would be fake or not, and to this day, you know,
you have people on both sides,
real or fake, but nobody
can disprove it. Nobody.
FORREST: 1967 is the same year
that the movie "Planet of the Apes"
is released.
This is the height of big-budget
Hollywood special effects back then.
If anything, the Patterson-Gimlin footage
looks more realistic
than the ape suits we see in that movie.
RYAN: You're talking about, you know,
two guys in the backwoods of Humboldt.
They didn't have deep pockets to build something like this.
So, how did these two cowboys
pull off the greatest thing in creature feature history?
And the thing is, is they didn't.
FORREST: There are no visible seams,
no zippers, no buttons.
It's not baggy.
You can actually see the creature's musculature
moving under its skin.
Even special effects experts can't explain that.
LAURENCE: But if this film of Bigfoot is real,
what type of creature might it be?
There have been several attempts to classify the animal
seen in Patterson and Gimlin's film.
It's analyzed by Stanford scientists Jessica Rose
and James Gamble in 1994,
and they're experts in physiology and movement.
They analyze the creature's gait,
and can't find any match to known species.
LYNNE: They concluded that this is not a gait
or a movement that could be replicated
by a person in a costume.
The relationship of bones, to musculature,
to skin and hair, is a unique thing
for different animals, and it really wouldn't be possible
for a human being to fake this type of difference
in gait and movement.
RYAN: In 1999, a pair of professors
from the University of Florida's anthropology department
also analyzed the film.
And in 2009, the film is broken down
frame by frame by an anthropologist
from the New York Museum of Natural History.
FORREST: As for what type of animal this is,
they have no idea.
These top scientists are at a loss.
It's possible that Patterson and Gimlin
have discovered an entirely new species.
CHRISTOPHER: There are many examples of creatures
that at first seemed mythical,
or their description seemed hard to believe,
such as the Komodo dragon,
a giant lizard that would eat sheep whole.
The narwhal, a whale with a horn on its head
like a unicorn.
LYNNE: The pelican-- an incredibly common bird
in contemporary life, was at one time
thought to be a mythological creature
back in the Middle Ages.
How about this? The giant squid.
For millennia, since at least the days of Aristotle
in the fourth century B.C., sailors would swear up and down
that they saw these massive 20-foot-long-plus squid
while out at sea.
There are thousands of depictions and stories
of people who claim to have seen the giant squid,
and yet still, it was considered a mythological creature.
It's another in a long line of fanciful tales
of make-believe sea monsters like the Kraken.
Squids just don't get that big. There's no evidence.
LAURENCE: Until one day, there is.
FORREST: Throughout the 19th century,
small pieces and remains of giant squid
would periodically wash up on the world's beaches.
And these would convince some scientists
of the giant squid's existence, but others kept on denying it.
They'd say that until we find a living one,
it's simply not proven.
It wasn't until a fishing trawler caught one
in 2004 that we realize that squids
of this size actually exist.
FORREST: They catch a nearly 30-foot-long giant squid
that's later named Archie.
It's been preserved by London's Natural History Museum,
and can still be viewed today-- proof positive of a giant squid.
So, hopefully one day Bigfoot can join the giant squid
as a proven animal, but it could be tough.
RYAN: A lot of people like to believe
that all of life has been discovered,
when it's quite the opposite.
Over 80% of life on this planet is undiscovered.
So, absolutely, a Bigfoot species
could be out there.
LAURENCE: Ever since large mysterious footprints
were first reported in Oregon in the 1950s,
there has been no shortage of Bigfoot sightings.
Institutions like the Bigfoot
Field Researchers Organization
have been cataloging accounts
since the 1990s.
Even today, they're reporting sightings
at a rate of four or more per month
across the U.S. and Canada.
LAURENCE: But in 2007, one in particular
makes headlines.
RYAN: In the Allegheny National Forest in Pennsylvania,
there is a new piece
of information that comes out
that's very intriguing.
FORREST: We get what could be the most compelling set
of Bigfoot images we've seen in 40 years.
CHRISTOPHER: One evening at about 10:02 p.m.
a motion-activated trail camera
captured several bear cubs
foraging for food.
RYAN: After that, you have another picture
that really, like, catch your attention.
Something else comes into frame
and is actually standing--
I like to call it downward-facing dog position.
And the way that it is smelling the ground
is exactly how primates do it.
And this comes to be known as the Jacobs Bigfoot,
after the camera's owner who set it up in the woods
to help him track deer.
It seems that the situation provides a pretty stark contrast
between what are clearly bears and what is clearly not.
It's fairly obvious when you compare the first photo
of the Jacobs Bigfoot with one of the bear cubs
taken in the same spot.
They're in the same pose, but their anatomy
is completely different.
LAURENCE: The following week,
the state of Pennsylvania's Game Commission
offers an explanation.
Sorry for all the Bigfooters out there, believers,
but the Game Commission come out to check out the area,
and their response is that it is simply a bear with mange.
Scientists love to cite Occam's Razor--
the concept that the simplest solution
to a problem is often the best and most likely.
If you're in Texas and you hear hoofbeats,
you should probably think horses and not zebras,
because horses are the more common animal.
Well, bears are super common.
LYNNE: Let's consider Ursus Americanus--
the American black bear.
What we know about this bear
lines up really well with the reported characteristics
of Bigfoot-- its size, its shape, its coloring.
It seems like a very likely explanation
for the Bigfoot legend.
CHRISTOPHER: When they stand on their hind legs,
black bears can reach up to six or seven feet in height,
which is similar in height to many reported Bigfoot sightings.
LYNNE: Seen from far away, from the right angle,
at the right moment, when it's standing up,
when it's moving bipedally,
it would be easy to mistake a black bear for Bigfoot.
LAURENCE: The vast range of black bears
could also support this.
FORREST: Black bears live in the Pacific Northwest,
the Northern Midwest, and the Rocky Mountain region,
Alaska, and the northeast from Maine
all the way down to Georgia.
All of these places have had Bigfoot sightings.
LYNNE: If we add in other species of bears
besides Ursus Americanus, we have the potential
for Bigfoot or bear sightings all over the United States.
LAURENCE: In 2014, Oxford University
genetics professor Bryan Sykes further tests this theory.
What Dr. Sykes did which was unique,
was instead of simply looking at sightings reports,
or photos, or tapes of Bigfoot, of vocalizations,
Sykes actually as a genetics professor
wanted to look at DNA samples,
and he requested Bigfoot investigators
from all across the world to send him their best examples
of Bigfoot DNA.
FORREST: Sykes collects 30 samples
of purported Bigfoot hair,
sent in from a wide variety of sources,
from hardcore cryptozoologists, to amateur Bigfoot hunters,
to roadside oddity museums.
And what he finds is really telling.
Almost all of them come from known animals.
They come from bears, they come from horses,
some of them even come from humans.
But there's one sample that isn't accounted for.
FORREST: Remember the theory that Bigfoot
is an unknown species?
Well, incredibly, Sykes' DNA analysis
of one sample actually does reveal the existence
of a previously unknown species.
But it's not an unknown ape, it's an unknown bear.
LYNNE: What we see is a hybrid between a brown bear
and a distant cousin of the polar bear
that was thought to have gone extinct a long time ago.
LAURENCE: While Sykes believes this bear species
may have given rise to the Bigfoot legend,
some other scientists aren't convinced.
Remember, Sykes' sample pool is just 30 specimens.
Are all the Bigfoots out there
just ordinary run-of-the-mill creatures?
We've still got a long way to go to figure that out.
Despite many long years of searching for proof it exists,
the legendary creature known as Bigfoot
remains more myth than fact.
Then, a chance encounter in 1974
convinces one man that he's finally solved the mystery.
LYNNE: It is undeniable that the real heart
of Bigfoot sightings have been in the Pacific Northwest
of the United States.
So, that's California, Oregon,
Washington-- that's where
the highest percentage
of sightings have been reported.
LAURENCE: But there have been alleged sightings
of a creature like Bigfoot in other places,
most notably Southern Florida.
RYAN: In 1974, Dave Shealy is 10 years old,
and him and his brother are walking
across the Everglades,
and they have an encounter.
FORREST: Dave is too short to see over the grass,
so his brother picks him up,
lifts him over his head,
and there he sees it
100 yards away.
LYNNE: And what he ends up seeing
is a creature that he describes as large, hulking,
walking on two legs, and hairy--
exactly how we see Bigfoot being described in other regions.
LAURENCE: But Shealy knows it by a different name.
This is something that he's heard stories about
his entire life.
He knows that what he's seeing in front of him
is the Florida skunk ape.
We already know that Bigfoot has been given
multiple names in multiple places.
Sasquatch is probably its second most famous moniker.
Some call it a yeti.
In regions prone to winter weather,
it's been called the abominable snowman.
But fewer people have heard of the skunk ape,
which is particular to this one unique swampy area.
CHRISTOPHER: The skunk ape is described in a way very similar
to your common Bigfoot sighting.
It's supposed to be about seven
to eight feet tall, although it's more common
for the skunk ape to be slightly smaller.
DANIEL PEREZ: Perhaps it might be a subspecies of Bigfoot.
The coloring of the hair is different.
Some of the behavioral characteristics are different.
LAURENCE: But there is one key difference
that gives the creature its name.
FORREST: The skunk ape has a distinct unpleasant odor.
It's been compared to a wide array of foul smells--
wet dog, hot garbage, boiled cabbage, rotten eggs--
hence the name skunk ape.
Maybe it's the heat,
maybe it's the muggy wet conditions,
or maybe nobody anywhere else
has gotten close enough to Bigfoot to actually smell it.
Maybe they all smell this way.
LAURENCE: Stories of a human-like beast
with an unmistakable stench
have long been part of local lore.
LYNNE: The native peoples of Florida,
the Seminole, the Miccosukee people
have stories of a creature described very similar
to what is now called the skunk ape.
RYAN: These legends of the skunk ape
go back to the times of Spanish colonization.
You know, we're talking 16th century.
FORREST: Then, throughout the early 20th century,
we get isolated reports from hunters and hikers
about strange hairy two-legged creatures
spotted in the Everglades.
Surprisingly, not much research is done at that time.
LYNNE: And the story really takes off
in the 1970s in Florida,
and we start to see many more encounters.
LAURENCE: More intriguing, these alleged sightings
increasingly come from larger groups
sharing the same story.
FORREST: In fact, in 1997, an entire tour bus of 40 people
all see the strange creature simultaneously
on the side of the road in broad daylight.
LYNNE: Before long, we start hearing reports
of encounters in the highly populated Broward County--
things like skunk apes breaking into people's homes,
or even stalking pedestrians on the street.
LAURENCE: Accounts become so frequent,
the state government takes action.
FORREST: In 1977, the Florida legislature
introduces a bill to try and protect
the skunk ape and the public.
LYNNE: The bill includes specific language,
making it illegal to take, possess, harm,
or molest any sort of humanoid or anthropoid creature.
FORREST: The bill doesn't pass,
but it does add a certain legitimacy to the idea
that skunk apes are real.
LAURENCE: One man who doesn't need convincing--
Dave Shealy.
FORREST: In 1994, Shealy opens
the Skunk Ape Research Headquarters
in Ochopee, Florida.
CHRISTOPHER: The Skunk Ape Research Headquarters
might at first appear like a tourist attraction.
It has a gift shop.
But in fact, Shealy claims that those sales
help subsidize serious research into the creature.
FORREST: Primarily, it's a hub
for legitimate paranormal investigators
to share information and gather resources,
and it's helped spawn some major breakthroughs,
including by Shealy himself.
LAURENCE: After a lengthy stakeout in 2000,
Shealy manages to capture video
of what he claims is a skunk ape in the wild.
LYNNE: We can see the creature moving through tall grass,
walking in what seems to be maybe ankle-deep water,
until it notices that it's being filmed,
and suddenly takes off.
RYAN: The thing with David's video,
is you take the still-frame shot of it,
people think, yeah, you're looking
at maybe a teenager Bigfoot,
or what we call in Florida a skunk ape.
But then, you watch the actual live video,
and for some of us, it kinda looks
like you could have thrown someone in a suit
and just had them run through the grass.
LAURENCE: In 2014, a Smithsonian Magazine journalist
named Joseph Stromberg
decides to get to the bottom of this.
CHRISTOPHER: Shealy told the journalist
that he believes skunk apes are drawn
to the particular area that they were investigating
because of the calls of other primates.
LYNNE: He had been following two skunk ape tracks,
and they led him straight to this barbed-wire fence
in the middle of nowhere that he described
as being some sort of secretive or mysterious
primate breeding ground
right there in the middle of Florida.
CHRISTOPHER: Stromberg was skeptical about this story,
but in fact confirmed that such a company did exist.
LYNNE: Is in fact a company
called Primate Products Incorporated
located in Immokalee, Florida,
where primates are bred.
LAURENCE: This leads Stromberg to speculate
that perhaps some of these animals got loose.
CHRISTOPHER: When Hurricane Andrew hit Florida in 1992,
there was extensive damage to Primate Products,
and they believe over 6,000 primates
may have escaped into the wild.
LYNNE: In addition, Stromberg turns up other reports
of people acquiring exotic pets
and then releasing them into the wild
once they are too strong or too powerful
to be cute anymore.
So, chimpanzees as pets are a common animal
that gets released in this way
and adds to that population of very unexpected primates
living in Florida.
LAURENCE: A report from the Sarasota Sheriff's Department
may offer further proof.
DANIEL: In 2000, a person who had claimed
that there was disturbances around their property
by an unknown critter
eventually get a picture of it,
and they wrote a letter as to what happened.
And they send it to law enforcement.
LAURENCE: Two experts examine the photo
and make a surprising discovery.
They determine that based on the creature's appearance,
the scale of its features,
the distance between different parts of its body,
that it is, in fact, an orangutan.
Not a creature that we would expect to see
in a Florida backyard, but not a skunk ape.
CHRISTOPHER: Stromberg concluded that people
who report the skunk ape are sincere,
but may not be seeing what Shealy claims they are.
Certainly, some people who see Bigfoot
are in fact misidentifying a monkey
that someone has released.
LAURENCE: Since the 1950s, most Bigfoot eyewitnesses
describe the creature as a hybrid
between an ape and a human.
CHRISTOPHER: There's a debate in the Bigfoot community
about what Bigfoot actually is.
Some believe that Bigfoot is more of a stray animal.
I think the ideal answer would be
that there's probably an unknown primate there.
CHRISTOPHER: But scientists are very skeptical
about the possibility that the United States
could support an undiscovered species of ape.
But it is possible that some of these
could be wild humans.
LYNNE: There have been reports
throughout history of wild men,
human beings, but who are living in a feral state--
not in cities, not in any sort of civilized way--
living like an animal.
RYAN: So, in South Central Texas in the 1830s
we have the story of the Wild Man of Navidad.
People were seeing what they were describing
as something that was Bigfoot-like,
covered in fur head to toe,
acting like an animal,
but with human qualities,
and that sparked everyone's interest.
LAURENCE: The descriptions line up perfectly
with later sightings of Bigfoot.
In some ways, this is almost the first Bigfoot legend,
but just going by a different name.
CHRISTOPHER: The Wild Man of Navidad was stealing piglets
and chickens, was leaving footprints all over the area,
was breaking into homes but only stealing food,
never valuables.
LAURENCE: For over a decade, the Wild Man of the Navidad
remains at large.
At one point, people looking for the wild man
even found a shelter in the woods
and conducted a stakeout.
But if that was where the creature lived,
it never returned.
RYAN: It was something nobody could get near,
and it had people interested and also worried.
So, in 1850, they ended up getting a posse together
to try and round up this wild man.
CHRISTOPHER: And upon investigating,
they found out that it wasn't a creature,
but it was in fact a person.
This particular wild man was an African slave
brought over that escaped immediately
and ran into the woods,
and was able on his wit and abilities alone
to survive for like 15 years before being captured.
LAURENCE: Could such wild humans
account for more supposed Bigfoot encounters?
One story about a purported feral human
came out of Arkansas in 1892,
when there were stories of what appeared to be a boy
running with a pack of wolves.
RYAN: I mean, this is Mowgli from "The Jungle Book,"
taken in by wolves and then raised,
and survived long enough in the wild as a wolf cub
before finally being captured by humans
and brought back to be rehabilitated.
Stories of feral humans have a lot of similarities
to stories of Bigfoot.
The creatures are usually reported as hairy,
living in the woods, leaving footprints,
stealing items.
LYNNE: The main difference is that in these cases,
the culprit, the wild person, is discovered.
LAURENCE: Is it possible that modern Bigfoot sightings
could also be of humans rather than of animals?
In the 1970s and 1980s,
there's a dramatic rise in homelessness
in the Pacific Northwest,
especially among veterans.
And around this time, there's also a noticeable uptick
of possible Bigfoot sightings around Washington state,
and a theory begins to emerge.
We have returning veterans from the Vietnam War,
many of whom were struggling with PTSD
and other societal issues, choosing to isolate themselves,
or being forced into homelessness,
living on the edges of society,
and perhaps appearing as these wild men.
To me, the story that epitomizes humans mistaken for Bigfoot
happens in Western North Carolina in 2017.
A self-identified shaman
is conducting some rituals in the woods
while wearing his ceremonial garb,
which is made of fur covering his entire body
from head to toe, including his face.
LYNNE: As a result of this,
the Greenville Police Department
started getting report after report
of people saying that they saw a creature
covered head to toe in fur moving about in the woods.
The police had to take this seriously.
CHRISTOPHER: One concern that law enforcement has had
across the country, is if people are out
hunting for Bigfoot, it is possible
they will mistake a human for a Bigfoot, and take a shot.
This brings us back to that idea of Occam's Razor.
What is the simplest explanation for all of these sightings?
We do have an incredibly common bipedal hominid
walking around all over the place,
and that's us-- people.
LAURENCE: Bigfoot has been compared
with many modern animals over the years,
most notably various species of primates.
It looks very much like an orangutan
or something of that nature.
RYAN: Some of the things these people are seeing in the woods
are legitimately
a silverback gorilla or a chimpanzee.
Then on top of that, you have wealthy people
that buy these pets,
and they just kinda lackadaisically keep 'em,
and they escape.
LAURENCE: But many experts believe
this doesn't fully explain Bigfoot.
Escaped monkeys typically don't grow
as large as Bigfoot
is purported to be.
LYNNE: There is no modern-day species
that really matches with the description of Bigfoot.
But scientists are quick
to point out that
in the not-so-distant past,
there was a creature
thought to be extinct that did match this description.
RYAN: Remains have been discovered of a creature
that most resembles Bigfoot,
and that is the species called Gigantopithecus.
LYNNE: Gigantopithecus is a primate
from the Pleistocene Era.
It was believed to have gone extinct
about 300,000 years ago.
LAURENCE: An ancestor of modern-day orangutans,
Gigantopithecus is thought to be the largest primate
to ever live on Earth.
JEFF: Gigantopithecus was enormous.
Its teeth were of such proportion
that we estimate its body mass
to be on the order of, oh, 800 to 1,200 pounds.
RYAN: We're talking about a 10-foot animal.
And when people describe seeing Bigfoot,
the sheer mass and size of it leads some people
to believe that Gigantopithecus,
or a relic version of it is Bigfoot.
Maybe it's evolved to be a little bit smaller,
a little bit more nimble,
or we're just not seeing the big boys,
and all we're seeing are the females.
FORREST: In the early 1980s,
American anthropologist Grover Krantz
becomes one of the biggest proponents
of the theory that Gigantopithecus
could perhaps be a candidate
for Bigfoot.
LYNNE: Considering this theory,
two problems stand out immediately.
One is that Gigantopithecus was thought
to be almost entirely exclusive to Asia.
And the second problem, of course, is that it's extinct.
RYAN: As far as where Gigantopithecus lives,
Krantz believes that a land bridge
formed across the Bering Strait that allowed Gigantopithecus
to cross over to the North American continent
during the Ice Age in search of better food
and warmer climates.
LAURENCE: As for their extinction,
he believes it never happened.
Scientists believe that given the vastness
of the ocean and the wilderness,
that there are numerous other seemingly extinct species
that we may find in fact still exist.
RYAN: Let's take the pygmy tarsier
and the Kashmir musk deer.
These are two animals that were supposedly extinct
that we have found are not.
LYNNE: What's amazing is that there was a giant fish,
a coelacanth that existed 60 million years ago
and was thought to be long extinct,
until we caught one in 1938 off the coast of South Africa.
And there's not just one of them.
A whole community of them was found to still exist.
So, clearly, our best understandings
of just how extinct an extinct creature might be
can be wrong.
LAURENCE: Gigantopithecus may not be the only extinct primate
that could fit the bill.
CHRISTOPHER: Bigfoot researcher John Napier
actually believed that Bigfoot
might be a different form of seemingly extinct ape
called Paranthropus.
RYAN: They're large, really big heads, big frames,
and really fit the look
of when people describe their experiences with Bigfoot,
what Bigfoot looks like.
See, with Gigantopithecus,
it was so massive, we really can't be sure
that it even walked on two legs.
But Paranthropus did strut its stuff.
LYNNE: This theory, the idea that a species
assumed to be extinct is not in fact extinct
is now the favorite explanation
of the Bigfoot Field Researchers Organization.
It is possible perhaps that at some point,
one or more of these species
came over the land bridge to North America
where their descendants have remained undetected,
but occasionally sighted.
FORREST: Bigfoot might be the most widely spotted cryptid
in history.
Hopefully, someday we'll finally get close enough to identify it.
And when we do, the scientific community
may be in for quite a shock.
Currently, there are more than
20 Bigfoot research associations
in the U.S. alone,
and dozens more worldwide.
Perhaps one day, we'll finally be able
to identify this elusive creature.
Until then, many Bigfoot hunters are only too willing to search.
I'm Laurence Fishburne.
Thank you for watching
"History's Greatest Mysteries."