Tonight, the world's most enduring
Deep-sea monster mystery.
I saw the head, the neck, and the huge body
Which I'd say was about 30 feet long.
Heidi hollis: We are talking about thousands of sightings,
And that's a conservative estimate.
It could be tens of thousands over the course of 1,500 years.
Despite so many sightings, the beast remains unidentified.
There are millions of species
That we haven't found or classified yet.
There's stuff out there that we don't know anything about.
As far as we can tell,
Nobody has ever captured a loch ness monster.
Now, we'll explore the top theories
Surrounding this elusive creature.
Hey, maybe it's a plesiosaur.
Kristyn plancarte: What about the thing that washed up
In stronsay, or the similar lake monster in sweden?
Jonathan bird: There are tons of eels in loch ness.
Is it possible that there is a gigantic eel?
Dustin growick: Many people still believe it's real.
Does the loch ness monster exist?
And if so, what is it?
[music]
Laurence: Northern scotland, August, 564 a.D.
According to legend, an irish monk named columba
Is attempting to cross the river ness with a group
When they stumble upon two men burying a friend.
This man had just been swimming when he was attacked
By an enormous water beast.
Dustin: You would think that after that exchange
The monks would try to find a different river crossing.
But columba stays, undeterred.
Maybe he didn't believe the locals,
Or he just thought that his faith will protect him.
Zak martellucci: He orders another monk
To swim across and retrieve a small boat.
As this monk gets about halfway across,
This creature suddenly appears out of the water,
Gives a giant, bellowing roar.
Laurence: Everyone panics, with the exception of columba.
He steps right up to the edge of the bank,
Makes the sign of the cross, and demands the monster
Leave the man alone.
Laurence: The creature supposedly obeys.
To the witnesses on shore,
It is nothing short of a miracle.
Karen: Columba eventually achieves sainthood,
And this tale is supporting evidence
For his faith and abilities.
And this story is retold for years to come.
Laurence: Debate continues for centuries.
What could this mysterious creature actually be?
In columba's time, and continuing
For several centuries after, through the middle ages,
Dragons are still believed to be real.
And so, many people think this is some sort of sea dragon.
But nobody has any concrete evidence of what it is,
Or if it even truly exists.
It remains an essentially local legend
For quite some time.
Laurence: Then, in the 20th century,
New visitors flock to the highlands,
Thanks to one remarkable invention--
The automobile.
By the early 1930s, there's a road built
Along the shore of loch ness.
Heidi: One afternoon in 1931,
A local couple were driving along there
When they spotted a large animal.
It was rolling and plunging on the surface of loch ness.
Immediately they report their experience
To the local papers.
When published, their story
Uses the now-famous key word, "monster."
Laurence: The loch ness monster--
A name that soon spreads far and wide.
Heidi: Now all of a sudden,
The tourists are not coming
To see the beautiful lake and the rolling hills.
They are coming to see the monster,
Who is soon lovingly called "nessie."
And guess what? They are spotting it, all right.
They are spotting it in droves.
Laurence: Soon, there are more eyewitness accounts of nessie,
And they seem convincing.
I saw a-- a large object.
It came right out of the water in front of me.
I was wading in the river fishing with-- fly-fishing.
The best view I ever had was the very first in 1934.
I saw the head, the neck, and the huge body
Which I'd say was about 30 feet long.
Laurence: Each new glimpse brings fresh seekers,
All with the latest technology.
Zak: We shouldn't have to wait long
Before somebody captures it on film,
And then we're bound to know what it is.
Laurence: In April of 1934, that finally happens,
And it becomes front page news.
A gynecologist from london named robert kenneth wilson
Went on a fishing trip over there to northern scotland
When he decided to go for a walk.
During his stroll, that's when he spotted something
Unusual in the water.
Luckily, he had his camera, and he snapped a picture.
And there we have it,
Probably the first photograph of nessie.
Laurence: Known as "the surgeon's photo,"
The image causes quite a stir.
Karen: Shows a silhouetted creature
With a long, slender neck, a small head,
And a large body emerging slightly above the waterline.
Dustin: This is amazing.
We finally have some visual evidence
To back up these eyewitness accounts.
And not only that, some experts
Think they can identify this animal.
Laurence: The creature's shape also strikes a chord
With british paleontologists.
So, what particular species do you think it is?
The evidence as I interpret it all fits--
And I know this is a fantastic statement--
But this all fits plesiosaur.
Laurence: Plesiosaurs are a marine reptile
Dating back millions of years.
Their fossils were first discovered in 1823
During a dig in England.
Heidi: Fossil hunter mary anning actually uncovered
A nearly complete skeleton of a previously unknown species.
It is given the name plesiosaurus,
Meaning "near to reptile."
Plesiosaur fossils have been found around the world,
But a major cluster of them comes from here in scotland.
We're talking about hundreds of specimens.
This was, at least at one time, this creature's main habitat.
Karen: These fossils show that the plesiosaur
Was an enormous water-dwelling creature,
Over 20 feet long.
They had broad, flat bodies with short tails.
Their limbs had evolved into four long flippers
That propelled them through the water in a flying motion.
Heidi: They breathe air, and so they would constantly
Have to come to the surface for oxygen.
Most notably, they had long thin necks.
The surgeon's photograph happens to fit that to a t.
And coincidentally, so do most of the witness statements.
Laurence: Though some believe nessie could be a plesiosaur,
The theory has one major flaw.
Dustin: Scientists believe that a mass extinction event
About 65 and a half million years ago
Killed about 75% of all species on earth,
Including dinosaurs and plesiosaurs.
A plesiosaur should not be inhabiting these waters today,
In saint columba's time,
Or any time during human existence.
They're supposed to be extinct.
Laurence: But is it possible the plesiosaur somehow survived?
When we say that 75% of the creatures
Did not survive the last mass extinction event,
That means that 25% did survive.
So, platypuses, turtles, crocodiles--
All kinds of animals actually did survive that event.
Laurence: Scientists point to a fish
Long thought to be extinct as an example--
The coelacanth, discovered alive in 1938
In south africa.
Karen: The entire scientific community believes
That the coelacanth dies off 66 million years ago.
There are no fossils after that.
It's the same time as the plesiosaur.
If the coelacanth can still be swimming around out there,
What's to say that a small number of plesiosaurs
Couldn't have somehow avoided extinction, too?
Laurence: But to many, the plesiosaur theory
Remains too far-fetched.
Dustin: The fact that they breathe air
Could account for the animal being sighted at the surface,
But I actually think that's evidence
Against nessie being a plesiosaur,
'cause it would have to surface all the time.
If that were the case, we'd have so many more photos and videos.
One would have probably already been caught
And put in a zoo by now.
Plus a creature as big as a 20-foot-long plesiosaurus
Would need a lot of food to sustain itself.
Zak: There's just not enough of a food source
For a massive beast, let alone a community of them,
Which there would have to be in order for this species
To survive this long.
Heidi: And honestly, the plesiosaur theory
Only hangs on the one photograph.
And before the surgeon's photo is published,
Absolutely nobody thinks it's a plesiosaur.
Laurene: 1934-- the first photo
Of the supposed loch ness monster
Incites public frenzy and a torrent of tourists
Looking for nessie.
But not everyone believes the image
Known as "the surgeon's photo" is authentic.
Dustin: Dr. R. Kenneth wilson, who submits this photo
To the daily mail, claims that it's real,
But others say "hold on, this is an elephant's trunk
"rising out of the water, or maybe it's a dolphin's fin,
Or something else."
Karen: What we do know is that the photo that's published
Is substantially cropped and zoomed in,
Which blurs the shape of the creature a bit
And skews any sense of scale or perspective.
But when some experts go back and examine
The original, uncropped photo,
They see something entirely different.
Seeing the uncropped version
Changes their perspective completely.
They believe that whatever this beast is in the water
Isn't anywhere near 20 feet long.
It's maybe three feet long, at the most.
Laurence: Is it possible that the most famous photo of nessie
Is somehow doctored?
Heidi: People question the authenticity
The moment this photo comes out in 1934.
But many people still believe this thing is real.
And there is no definitive proof otherwise.
Then, in 1994, the photo's whole provenance
Comes into question, thanks to a deathbed confession
By a man named christian spurling.
He claims that in 1933, his stepfather was hired
By the daily mail to find evidence
Of the loch ness monster.
Spurling is the stepson of a big-game hunter
And filmmaker named marmaduke "duke" wetherell.
Karen: So, duke goes on this expedition to scotland,
And it doesn't take him long to find
These really large animal tracks near the banks of the loch.
Judging from the size of the footprints,
Duke estimates the animal to be at least 20 feet long.
Laurence: Wetherell sends plaster casts of the tracks
To a london museum.
When the results came back, they find that the tracks
Didn't come from a monster, but they came from a hippo.
It sounds unusual because we all know
That hippos do not come from that area.
But back then, hippo's feet were used as umbrella holders
And ashtrays, so it wasn't that uncommon.
Dustin: So, one of two things is happening here.
Either duke faked the tracks, or someone was fooling him.
The daily mail is not happy about either of these options,
So the paper publicly ridicules him.
Laurence: According to spurling's confession,
Wetherell concocts a scheme to save his reputation.
Duke goes to his stepson, who happens to be a model-maker,
And asks him to fabricate something
That looks like the eyewitness descriptions of the beast.
So, using plastic, wood, and a toy submarine,
They create this model of a creature
With a long neck and small head.
Heidi: And then, duke goes to the loch with his other son
And creates that iconic photograph.
But in reality, it's just a picture of the model
Floating in the water.
Laurence: Now, wetherell just needs a way
To make the photo public.
The perfect solution?
The surgeon, dr. R. Kenneth wilson.
Duke realizes the best way he can pull this off
Is if he finds someone trustworthy
Who can claim the photo as their own.
So, he passes the photo on to wilson,
The very same surgeon who publicizes the infamous photo.
Heidi: The surgeon's photo is really a game-changer.
It unleashes a torrent of tourism
That still is going on to this day.
Laurence: Over the years, there are more fake photos of nessie,
All of them eventually debunked.
Then, in 2016, there's suddenly new evidence
That suggests the monster could be real.
Dustin: Researchers from kongsberg maritime
Send an underwater drone deep into the loch
To search for any evidence of the monster.
And surprisingly, the sonar returns images
Of something that has the shape of the monster's head and neck.
At first, this is big news.
Laurence: Until it's determined to be a prop from a movie.
Dustin: In 1969, a sherlock holmes movie
Was shot at the loch.
In the movie, there's a scene where the loch ness monster
Attacks the heroes.
But during the filming, director billy wilder
Takes a look at the monster prop
And decides he does not like the humps on the back.
So, they remove the humps, and accidentally cause the prop
To sink to the bottom of the loch.
Heidi: There's a lot of fakery
Surrounding the loch ness monster.
People love getting their 15 minutes of fame from this.
Every nessie sighting gets attention,
And people love getting attention.
Laurence: But the sheer volume of sightings throughout time
Convince many that nessie is real.
We are talking about thousands of sightings,
And that's a conservative estimate.
It could be tens of thousands, over the course of 1,500 years.
Dustin: Before cameras, before photoshop,
Before robotic toy submarines.
Sure, a few dozen sightings may be fake.
But all of them?
[clicks tongue] no way.
Laurence: A key piece of evidence for believers--
A discovery in 1808 on the scottish island of stronsay,
Just 120 miles from loch ness.
According to eyewitnesses, the corpse of a strange animal
Washes up on the beach and a crowd gathers to see it.
It's the rotting carcass of an enormous,
Unidentified sea beast, and the locals
Have never seen anything like this.
Eyewitnesses call it the "stronsay beast,"
And describe it as having a serpentine-like body
With a long neck and six limbs that resemble paws.
They say its head is small like a sheep's,
And its eyes are similar to a seal's, but bigger.
It has some short hairs around its head and neck,
And skin that is rough to the touch
And grayish in color.
Zak: The measurements they take show how gigantic
This thing actually is.
It's 55 feet long, with its neck alone
Measuring 10 feet.
Laurence: Authorities document the creature
And take sworn witness statements.
This is the early 19th century, so they can't photograph it.
But they also know the story won't be believed,
So they need to prove it somehow.
So, they bring all the eyewitnesses
To the capital where they can swear before a magistrate
That what they saw is the truth.
We still have these records,
Along with drawings that they made.
Karen: The carcass is quickly decomposing,
And they lack the right equipment to transport
Or preserve this massive animal,
But they do take samples of the specimen.
The skull is saved and sent to london
For further examination, but unfortunately,
It is destroyed during the blitz of world war ii.
The vertebrae, on the other hand,
Are sent to leading anatomist john barclay
From edinburgh's most successful school of anatomy.
He concludes that this is unlike any other creature
He's ever seen, opening the door to the possibility
That this is a newfound species.
Heidi: The connection isn't initially made
To the loch ness monster, because it's not the 1930s yet,
So nessie fever has not swept the nation.
The legendary creature is not famous yet.
But once it becomes famous, theorists realize,
"hold on, this might be the same animal."
Laurence: The fact that stronsay is just 120 miles from loch ness
Earns extra attention.
And the physical description of the two creatures
Is strikingly similar.
Gray skin, long neck,
Some kind of flipper-like appendages, small head.
The only real major difference I would say is the size.
The stronsay beast according to those eyewitnesses
Is much larger than anyone has ever claimed
The loch ness monster to be-- nearly twice the size.
That doesn't necessarily rule out the same species though.
Perhaps nessie is just smaller.
Dustin: Or, there's an even more compelling idea.
What if the creature in loch ness
Is a younger specimen?
What if the loch is where these animals breed?
It certainly happens.
Salmon swim in all the way from the north sea
And breed in the river ness and the loch.
It's an annual event.
Laurence: This may also explain the inconsistency of sightings.
Zak: If that's the case, the animal breeds
And raises its young in the loch,
But then it migrates out into the sea.
So, the reason people don't see it all that often
Is because it doesn't live in loch ness full time.
Kristyn: It's possible.
Loch ness and stronsay are actually connected by water.
Both the caledonian canal and the river ness
Connect the loch to rosemarkie bay,
And ultimately the north sea.
So, it's entirely possible that whatever washed up
On the isle of stronsay is the same species
As the loch ness monster.
Laurence: If the loch ness monster exists,
The waters it lives in remain largely unexplored.
But as marine science evolves,
New theories emerge about what nessie might be.
Over time, modern technology has allowed scientists
To dive deeper into bodies of water than ever before.
And the diversity of life there is amazing.
Zak: And the more species we discover,
The more we have to compare to the loch ness monster
To see if they're a match.
Laurence: And that approach has yielded
One particularly compelling candidate.
In 2012, biologist jeremy wade publicizes a theory
That some scientists have held for years
On the origins of the loch ness legend.
Nessie may in fact be a creature that scientists already know--
A highly-elusive, very mysterious species,
But one that is very real.
The greenland shark.
Dustin: Why a greenland shark?
Why this animal in particular?
Upon first blush, this theory seems way out there.
For decades nessie has been described
As more of a dinosaur-like creature.
But that belief stems from a photo
That we now know to be a hoax.
Laurence: What if nessie is not the long-necked beast
In the surgeon's photo, but something else entirely?
Kristyn: Like nessie, greenland sharks are elusive.
They tend to prefer very deep, very cold water.
That makes them hard to study.
They are rarely photographed or filmed.
A lot of what we know about them has only come to light
In the past couple of decades,
Despite the fact that our best guess
Is they've roamed the earth for over 100 million years.
Dustin: In fact, the first time one was photographed
Wasn't until 1995.
And when you first look at it,
You may not initially see nessie, but keep looking,
And think about some of the eyewitness accounts.
It could fit.
Laurence: Greenland sharks are typically mottled gray
Or brown-- the same colors used
To describe the loch ness monster.
And they're big.
Greenland sharks can get to like 20 feet long
And like four tons.
So, they're very, very large animals.
They can actually be larger than great whites.
Laurence: Unlike most sharks, they have a small dorsal fin.
Zak: If a normal shark were cruising along the surface
Of loch ness, people would know it,
It's instantly recognizable.
But the odd, stubby fin of the greenland shark
Could easily be mistaken for something else--
Possibly the head or a hump of some kind of sea monster.
Dustin: Which definitely applies to most sightings of nessie.
Witnesses often describe multiple humps
Undulating through the water.
When you think back to the time of saint columba,
Through the middle ages, and the nessie sightings
Even up to the 1800s, there are still people around
Who believe in things like mermaids
And all kinds of fantastical creatures.
So, it's not surprising that somebody could catch a glimpse
Of a bizarre-looking shark like this and think
That it is a monster in loch ness or the river ness.
I mean, it kind of does look like a monster.
Laurence: According to some scientists,
Greenland sharks also move like the loch ness monster.
So, most people imagine sharks as being fast agile hunters.
You think of like a great white or a mako shark
Chasing down a meal.
Nessie sightings tend to describe a slow-moving animal.
Jonathan: Greenland sharks live
In a completely different habitat
Where the water's really cold,
And they have a very slow metabolism.
So, they swim slowly, they eat slowly.
They do everything slowly.
Dustin: That is why they're sometimes called sleeper sharks.
If an enormous greenland shark surfaced
And moved along the water of loch ness that slowly,
It's easy to see how it could be misconstrued
As something other than a shark.
Zak: And why don't we see nessie very often?
Because a shark doesn't have to come up for air.
It may occasionally make its way to the shallows,
But not very often.
These greenlands love the depths.
Kristyn: The problem with the greenland shark theory
Is that loch ness is a body of fresh water.
For a long time we've thought that greenland sharks
Are saltwater creatures.
Laurence: But new evidence suggests otherwise.
Greenland sharks have recently been filmed
In canada's st. Lawrence river.
Kristyn: In fact, they go all up and down the st. Lawrence seaway
Through america and canada, and that is entirely freshwater.
Laurence: A similar freshwater route
Connects loch ness with the north sea.
Dustin: If greenland sharks can live in both freshwater
And seawater, it's entirely possible
One could survive in loch ness,
Or at least migrate in from time to time.
Zak: Maybe there's even a chance that the stronsay beast remains
Were misinterpreted, and it was some kind of large shark
That was capable of going back and forth
Between the sea and the loch.
All of this evidence excites the scientific community.
There are so many similarities between greenland sharks
And nessie, experts think that they've solved the mystery.
Laurence: A 2016 experiment at the university of copenhagen
Only adds to that excitement.
These scientists take 28 greenland sharks,
And have them radiocarbon dated to determine their age.
Shockingly, one of them is over 400 years old.
Zak: 400 years makes the greenland shark
The world's longest living vertebrate.
To give you an idea of how incredibly old this is,
There could be a shark swimming out there that was alive
Before the pilgrims left England on the mayflower.
The team also finds that these sharks
Only grow about a centimeter every year,
And they don't even reach sexual maturity
Until they are about 150 years old.
Zak: For some, this seals the deal
That the loch ness monster is a greenland shark.
That longevity could be key
To how isolated the sightings have been.
Nessie seems to be a solitary creature.
No one has ever seen two at once.
Most animals, you would need a family of them
Living in the loch and regularly breeding
To account for so many years of regular sightings.
One single greenland shark could be responsible
For all of the sightings dating back to the 1600s.
Laurence: To find out if a greenland shark
Is living in loch ness,
A team looks for proof in 2017.
A team of scientists led by dr. Neil gemmell
From the university of otago in new zealand
Did a really interesting study.
They went to loch ness and they took water samples
All over the lake-- the middle,
The sides, the ends, everywhere.
From a half a liter of water,
We can get a very, very good catalogue
Of life within the loch.
Jonathan: They did a dna analysis of all the dna
That they found in that water.
So, in theory, any living creature
That has been in that water would leave a dna trace.
Zak: If there's a shark in there, they'll know,
Along with anything else that might be swimming around.
Laurence: After two years, on September 5th, 2019,
They announce their results.
First and foremost, they found no evidence
Of jurassic-era animals, including plesiosaurs.
Zak: But more importantly, they found no evidence
Of shark dna, including greenland sharks.
Kristyn: If we think the creature might be migrating
In and out of the loch,
And maybe it's been away for a while,
Perhaps the shark is still a candidate for nessie.
But that dna test makes things a whole lot less likely.
Zak: This study wasn't completely fruitless though,
Because they did find the dna of countless other species,
Including an incredibly large deposit
Of another potential nessie candidate.
Across nearly 1,500 years of sightings,
Witnesses and scientists alike have been fascinated
With the mystery of scotland's beloved nessie.
But a closer look at results from a 2019 dna test
Might finally reveal the secrets of what's living in loch ness.
Zak: Throughout the years, since at least the 1960s,
And maybe even before, modern technology has been used
To try and solve the mystery of the loch ness monster--
Everything from sonar, to thermal imaging,
To hydrophonic soundwaves.
But none of these techniques have given us concrete results
Or gotten us any closer to legitimate answers.
However, anybody who has ever watched a crime show
Knows that the best evidence to provide the identity
Of the culprit is dna evidence.
Laurence: In 2019, a team of scientists from new zealand
Finally complete their dna analysis of water
From loch ness.
While there's no trace of greenland sharks,
What they discover unleashes new possibilities for nessie.
They find about 3,000 species, if you can believe it.
Most of those are tiny plankton, roundworms,
Nematodes, small crustaceans.
Of the larger fish, they find salmon, pike,
Stickleback, lamprey, a few others.
They even find dna of land-based creatures
That sometimes end up in the water
For one reason or another, including dogs, cattle,
Sheep, rabbits, and even humans.
This tells us that this test is very sensitive.
Even animals that rarely go in the loch are detected.
But the largest amount of dna they find
That is detected in almost every single sample
Is eel dna.
Jonathan: There are a ton of eels in loch ness.
It is one of the principle spawning grounds
Of the european eel.
Now, most of these eels, they only grow
To be about 0.8 meters.
So, they're not exactly monsters,
But could there be a monster eel?
Very possible.
Every single sampling site that we went to pretty much had eels.
And the sheer volume of it was a bit of a surprise.
Kristyn: The largest eel in the region
Is the european conger.
It can grow to almost 10 feet long
And weigh up to 160 pounds.
Could that be nessie?
Jonathan: Eels are migratory fish,
So if someone saw an eel in loch ness,
It's pretty easy to assume that they could think
That that's the loch ness monster.
Zak: Once you have an eel in mind, and you look back
At the videos and images of nessie,
You realize it could be possible.
Laurence: Especially if you analyze the way
Both nessie and eels move.
The loch ness monster has often been described
As a serpentine-like monster,
Maybe snake-like, or perhaps, eel-like.
If any animal could look like a sea monster,
An eel is a prime candidate.
It really has a classic serpentine look.
Eels move in a slithery, sort of snake-like way,
Where their body curves, and that's exactly what people
Say the loch ness monster looks like.
So, it's really possible that they saw an eel
With those hump-like shapes, and they thought,
"that's the loch ness monster."
Laurence: A 2007 video shot by retired engineer gordon holmes
Seems to support this theory.
Dustin: In 2007, holmes makes some trips to loch ness
To perform some amateur experiments,
Just for fun.
Kristyn: At first, he records some sounds
Using hydrophonic equipment.
Then he sets up a camera to capture video of the lake,
But he doesn't find anything out of the ordinary.
Laurence: That is, until his visit on may 26th.
Dustin: Holmes spots some movement in the water
As he's driving, and pulls over and grabs his camcorder.
His footage clearly shows some type of large animal
Moving through the water.
Though it's hard to tell, it appears as though it's moving
In a serpentine fashion,
Almost slithering through the loch.
Karen: This is some of the best video ever captured
Of a creature on the surface of loch ness.
Holmes purposely zooms in and out while he's shooting
To make sure the shoreline and other landmarks are visible,
So the footage can be analyzed later.
Laurence: Holmes sends his footage to a forensic team
To determine the animal's size and speed.
They find that it's 10 to 15 feet long
And swimming at a speed of six miles per hour.
Based on movement analysis, they find a strong likelihood
That this animal is an eel.
Eels are the most common animals in the loch,
And it's very likely that most of the sightings over the year
Have been related to eels.
Zak: At the time, this is long before the discovery
Of eel dna in the loch,
So they come to this conclusion all on their own.
Kristyn: Eels can also appear brownish gray in the water
And have very smooth skin like the nessie descriptions.
The so-called "humps" that people see
Could be the serpentine curves of the eel as it swims.
And the whole "long, thin neck" concept
Could fit with the eel as well.
They have a long, thin everything.
Dustin: But at 10 to 15 feet long,
If holmes' research is correct,
That would still be an eel of massive proportions.
And in fact, they did develop an amazing new science
And a way to study bodies of water
And what lives in them.
Zak: But of course, potentially identifying
The loch ness monster brings a ton more attention
To their research.
Laurence: When a dna profile of life in loch ness
Is completed in 2019,
It uncovers a wide array of species,
But it doesn't identify everything.
Some of nessie's most passionate researchers
Are quick to note that according to the full 2019 report,
The source of 20% of the dna collected is unknown.
And that opens up a whole new world of possibilities.
Maybe the monster isn't a plesiosaur, or a shark,
Or an eel, or any species
That we've even encountered before.
All of the previous attempts to prove that it is this animal
Or this other animal have been destined to fail
Because it's none of these.
Karen: We may not know what it is
Because we just don't know what it is.
Based on all this unidentified dna,
Could nessie be a completely undiscovered,
Previously unknown species?
Jonathan: If there's one thing that all underwater explorers
And scientists can agree on, it's that we have not found
All the species in the ocean.
There are hundreds of thousands, maybe millions of species
That we haven't found or classified yet.
There's stuff out there that we don't know anything about.
Laurence: If nessie's species is unknown,
How can we ever identify it?
Pretty much the only way we can properly identify
A new species-- whether it's a tiny insect
Or a giant lake monster-- is to find a specimen.
That's how science proves and classifies new animals,
Plants, and even bacteria.
Either living or dead, we have to capture one.
Kristyn: As far as we can tell, nobody has ever captured
A loch ness monster.
There may have once been those remains
On the isle of stronsay,
But we're not actually sure it's the same animal.
And in any case, none of that dna survived.
So, there's no way to compare the stronsay beast dna
With the unknown dna that we have from the loch.
Dustin: So, we're stuck with trying to catch
This elusive animal in loch ness.
But for 1,500 years no one has even come close.
We're still trying to get a good photograph,
Let alone trap the thing.
Laurence: The problem lies
In the incredibly challenging conditions at loch ness.
Jonathan: First off, loch ness is huge.
It's 23 miles long, it's a mile wide,
And the most important thing, 750 feet deep,
Which is impressively deep for any lake.
It contains more water than any other lake in the uk.
In fact, it contains as much water
As all the lakes in England and wales combined.
So, it's a large place to look for a monster.
Karen: But the size isn't the only reason
It's hard to explore.
Loch ness is full of peat,
Which is organic matter from plants
That's constantly breaking down in water.
It makes the water dark brown, almost black.
Visibility is only a couple of feet at most.
And even if you were to dive down for a look around,
The temperature is not survivable.
Loch ness has an average surface temperature
Of 42 degrees fahrenheit.
And as soon as you get about 20 feet down,
It has what is known as a thermocline.
It's a stratification of the water,
Almost like an invisible wall, where suddenly the temperature
Can drop 10 or 20 degrees.
Without a very advanced modern dry suit,
A diver could freeze to death and drown in about six minutes.
Kristyn: I'm not sure that this thing
Is possible to catch in loch ness.
Laurence: But could another lake linked to loch ness
By a waterway offer fresh hope
Of capturing a creature like nessie?
According to some, the answer is yes,
And sweden's storsjön lake is the ideal location.
Dustin: Both are freshwater and fairly cold.
Both share similar biological diversity,
Oxygen levels, et cetera.
If something can live in loch ness,
It can most likely live here too.
Laurence: Like loch ness, it has a long history
Of monster sightings.
There have been centuries of reported sightings
Of a creature with the same physical description.
In swedish, it's called storsjöodjuret,
Which literally translates to "the great lake monster."
It's first written about on a runestone
That dates all the way back to the year 1050.
It's got this depiction
Of a long serpentine water monster on it.
Laurence: Conditions in the two lakes are similar,
But there's one key difference.
Storsjön lake is much cleaner and clearer,
And much less hazardous to explore.
Laurence: And that makes spotting a monster much easier.
Zak: Thanks to much more favorable conditions,
The storsjöodjuret has been captured
Easily on video from far away,
Most recently in a 2008 documentary
That also shot infrared footage.
And attempts to track the specimen
Have already been mounted.
Laurence: Researchers at the lake monster center in storsjön
Plan to continue their search efforts.
If they're successful, all we have to do
Is compare the swedish creature's dna
To all the unknown dna from loch ness.
If any of it matches, we've identified our monster
And discovered a brand-new species.
That would be among one of the most incredible
Scientific discoveries in history.
Karen: As many as 18,000 new species
Are identified every single year.
So, the possibility is out there.
I hope one day we can add nessie to that list.
Laurence: Over long centuries, many theories have emerged
About the origins and existence
Of the mysterious loch ness monster.
Each offers an intriguing possibility,
But none are airtight.
You say, hey, maybe it's a plesiosaur,
But there's no evidence any of them survived extinction,
And we'd see an air-breathing creature much more often.
Karen: So, maybe it's a greenland shark,
But shark dna wasn't found in the loch.
Zak: Well, what about all the eel dna?
But could an eel, even a giant one, grow that big?
What about the thing that washed up in stronsay?
Or the similar lake monster in sweden?
Heidi: To be honest, any one of these creatures
Could be what was spotted in loch ness,
Or perhaps it's more accurate to say
All of these things could be.
Laurence: What if it's not loch ness monster,
But monsters?
Dustin: We talk about the loch ness monster
As this monotypic creature, like there's just one of it.
There's only ever been one nessie.
But given the time period, 1,500 years of sightings,
That's highly unlikely.
There's absolutely no reason it has to be one thing--
And the same thing-- over centuries.
Kristyn: Let's start with the eel theory.
For sure, some of the things that people have seen
In the loch over the years have been eels.
Just look at the gordon holmes footage,
And that's obvious.
Karen: It's a common animal in the loch,
And when you're scanning from far away
Looking for any kind of movement on the surface,
A large swimming eel could certainly catch your attention.
Zak: How about a greenland shark?
Well, we know they're swimming around in the north sea,
And they can and do sometimes go up river
In the freshwater areas.
It's quite likely a predator like that
Could follow a bunch of salmon into the river ness
And could conceivably make it all the way into the loch.
A lot of animals that sharks like to eat
Make that trip, including seals.
While there wasn't any shark dna in 2019,
There is still a good chance that a shark has been spotted
In the loch across the thousands of other sightings.
Laurence: And what about the plesiosaur theory?
Heidi: I don't necessarily think
There's a living, breathing plesiosaur
That is swimming around there.
But I do think the plesiosaur may be what's behind the legend.
Scotland and the uk in general
Are teeming with plesiosaur fossils--
Fully-intact skeletons of creatures
That back in the middle ages would have been assumed
To be monsters.
Water beasts, just like saint columba saw.
Imagine in 500 or 600 ad,
You stumble upon the remains of a plesiosaur.
You would certainly tell your buddies back at the ale house
About the crazy giant long-necked creature.
It's quite possible that this tale eventually morphed
Into the loch ness monster legend.
Heidi: As for the stronsay beast,
Whatever it is, it really doesn't matter.
If it washed up on the shore of the island,
We know there's a direct path of waterway
That connects back to the loch ness.
Kristyn: And any migratory creature,
Whether it's a shark, a whale, or anything less,
Could be swimming back and forth from the sea to the loch.
Heidi: Some of the loch ness sightings
Could be the same animal.
Laurence: Or perhaps an unidentified animal
From even further away.
Karen: Across 1,500 years, some of the loch ness sightings
May well be an unidentified new species.
Even the dna results bear that out.
They can't identify every living thing in the loch.
Kristyn: But if sweden's storsjön lake
Is hiding the same species,
Maybe we'll have an incredible discovery soon.
Dustin: Still, even if they identify the storsjöodjuret
And identify one in loch ness as well,
That doesn't mean that gordon holmes didn't see an eel,
Or others didn't see other animals.
A new species would be a revelation,
But remain only one piece of the puzzle.
Heidi: And still, there will always be those people
Who believe nessie is a hoax.
We know for a fact that plenty of nessie witnesses
Have been duped by hoaxes.
It happened to a sonar team that found a movie prop.
And in fact, it happened to millions of people
Around the globe, thanks to the surgeon's photograph.
Dustin: So, yes, nessie is also a hoax,
But not just a hoax.
There's much more to the monster than that.
Karen: One day, we may get the perfect biopsy,
The perfect picture, the perfect bone specimen,
Or maybe a strange long-necked creature
Will just walk right out of the loch and say hello.
And when that day comes, it'll be time
To break out the champagne.
Zak: But until then, I think we shouldn't limit our minds
To what nessie could or couldn't be.
Because it could be something new next year.
Dustin: The possibilities are endless,
And that is what has kept people
Fascinated with nessie for so long.
Despite the many challenges,
Thousands of amateur and professional researchers
Still spend time at loch ness every year
Hoping to unmask the monster.
Perhaps modern technology will soon provide us
With a clear picture of what's hiding in the depths.
Until then, there's no shortage of people willing to look.
I'm laurence fishburne.
Thank you for watching "history's greatest mysteries."