[William Shatner] Monstrous ancient beasts
who once roamed our planet
lay hidden beneath our feet...
...apocalyptic disasters
that transformed prehistoric Earth...
...and cutting-edge technology that could one day
resurrect the dinosaurs.
[roars]
Stegosaurus,
velociraptor, triceratops
and the mighty Tyrannosaurus rex.
It's intriguing to think that, millions of years ago,
colossal creatures reigned supreme on our planet.
And while scientists have been studying the giant fossils
of what we call "dinosaurs" since the early 1800s,
the fact is, we know very little
about these extraordinary beasts.
What more can be revealed
about the existence and extinction
of the most baffling behemoths to ever roam the Earth?
Well, that is what we'll try and find out.
♪ ♪
It's funny to think that a group of long-extinct,
incomprehensibly massive "giant lizards"
are as beloved to us as a puppy dog.
Today, dinosaurs are an enduring fixture in popular culture,
but what do we really know
about these extraordinary, diverse creatures
who have captivated our imagination for centuries?
Dinosaurs are a hugely fascinating group of animals
for a massive chunk of humanity.
It's like people of all groups,
all nationalities, all ages--
from young kids to old people--
everyone's interested in dinosaurs.
I mean, the whole idea that there's a group
of often gigantic reptiles that lived millions of years ago,
is one of the key things
that makes us really interested in them.
[Ben McGee] I think dinosaurs are central
in the collective social imagination now
because they hint at the existence
of a full and complete alien Earth
that none of us experienced.
When we discovered "them,"
the giant lizards, something totally different
than the life we have today,
well, that has a mystique to it that just doesn't go away.
But we really, ultimately, don't know much
about the dinosaurs and the world they inhabited.
[Nick Longrich] The first dinosaur to be excavated
that was named would be Megalosaurus,
and this was described in 1825
by William Buckland, an early paleontologist.
And at the time, they thought it was a bear-like creature.
They didn't really know that Megalosaurus
was a dinosaur then because the concept of "dinosaur"
had not yet been invented.
That fell to another paleontologist, Richard Owen,
working at the British Museum in London,
who recognized that animals like Megalosaurus
were a completely new group of reptiles
that he named "Dinosauria."
Today, every week or so,
new dinosaurs are being discovered.
There are so many species
being discovered, you literally can't keep track of them.
I think the latest count is something between
1,300 and 1,400 known species,
and dozens of new species are found every year.
Assuming dinosaur diversity was roughly comparable
to modern large mammal diversity,
that would suggest that something like
a quarter of a million species might have existed.
[Shatner] Dinosaur fossils have been found
on all seven continents.
Paleontologists have unearthed giant, lumbering herbivores...
...swift, two-legged predators,
monstrous creatures that roamed the ocean depths
and flying reptiles that were the size of a fighter jet.
And despite everything we've uncovered,
these creatures are still one of Earth's greatest mysteries.
The Field Museum of Natural History, Chicago, Illinois.
Every year, more than a million people come to see
the museum's most popular attraction,
the most remarkable Tyrannosaurus rex skeleton
ever found,
a fossilized monster affectionately called Sue.
[Jingmai O'Connor] Sue the T. rex
is the most famous fossil in the world.
It's famous because it's the most complete
adult T. rex that has ever been discovered
in 120 years of T. rex research.
And we have about 73% of the bones,
so 280 of the 350 bones that make up the skeleton.
Sue was first found near Faith, South Dakota, in 1990.
It was found by Sue Hendrickson
and a team of commercial paleontologists
that were looking for fossils.
[Naish] This is one of the biggest,
most powerful land predators that's ever existed.
It has a total length of roundabout 13 meters.
It would have weighed roundabout ten tons.
Tyrannosaurus rex has an incredibly broad,
hugely powerful, very heavily muscled skull
and its teeth are rounded and cross-sectioned.
They're more like-- kind of like railroad spikes.
This dinosaur was able to take among the most powerful bites
of any land-living animal in history.
So, it is an awesome animal.
It makes perfect sense that people
are really obsessed with this incredible animal.
[Shatner] Scientists have estimated
that there was once two and a half billion
T. rex dinosaurs on Earth.
Yet, so far, we've only found about 30
relatively complete skeletons.
And this astonishing low percentage of discovery
can be applied to many other species
who have laid buried for millions of years.
I'm sure that humans have been tripping over dinosaur bones
for thousands of years,
but they weren't recognized as fossils.
The oldest known dinosaur that we can see right now
is a dinosaur from Tanzania that is called Nyasasaurus.
It's about 237 million years old.
But we don't know the total number of dinosaurs
that ever existed and probably never will.
If we go back to the turn of the last century,
to, say, 1900,
there was one new dinosaur species discovered
and published about every year.
By 1970, it was half a dozen.
Now it's one a week.
I would guess that we haven't even come close to discovering
one percent of the dinosaur species that ever lived.
And then there are certain environments
that just don't preserve geologically.
For example, there were probably alpine dinosaurs.
Think of today's mountain goats and bighorn sheep.
Well, mountains erode.
In order to form fossils, you need places
that collect sediment, not places that shed sediment.
So, there are, there are just some dinosaurs
that we will not discover, I think, ever.
-[snarling] -[Longrich] There's a huge
amount of diversity out there waiting to be found.
And sometimes, we find something that completely surprises us,
that kind of overturns our thinking.
One of the strangest out there is there's an animal
called Yi qi, from China...
...and it has these bat-like membranous wings
it could fly on.
But the absolute strangest dinosaurs,
in my mind, would have to be the alvarezsaurs.
And I described one of these animals,
a little animal called Albertonykus.
They have these incredibly short forelimbs,
but they're very stoutly built,
and they had a single hooked claw.
They'd take these claws, rip into logs,
rip into termite nests,
and put their long, little snout down there
and eat the insects.
So, dinosaur anteaters. In my mind,
that's the strangest thing they ever came up with.
[Shatner] Paleontologists have unearthed
all kinds of bizarre dinosaur species,
including Spicomellus,
an armored tank with spikes fused directly to its ribs,
and Deinocheirus,
a massive omnivore that combines traits
from several different branches of the dinosaur family tree.
Yet, there are countless questions
that remain unanswered.
[Naish] We are still just scratching the surface.
We only know a tiny percentage
of the things that we would like to know and which we could know.
There's a massive wealth of dinosaur finds
still yet to be made.
What kind of animals dinosaurs were like when they were alive,
what their social behavior was like,
how they interacted with one another,
exactly what they looked like
and exactly what they did with their appearances,
how they interacted with one another
during, like, mating displays.
We know almost nothing.
[Longrich] The evolutionary relationships of dinosaurs,
when they evolved, where they evolved, when they went extinct,
a lot of these things we still need to understand.
How are all these various species related?
How is a T. rex related to a brontosaurus,
related to a triceratops,
and the-- related to a velociraptor?
Because if we had a complete evolutionary tree,
we could see when certain link groups appeared
and where they appeared and how their anatomy evolved.
It would help us piece together their evolution
in a far more complete way.
And we're trying to build something like that,
but it's incredibly difficult,
and nobody can seem to agree on the answer.
There's still a lot to be discovered.
[Shatner] The Yucatán Peninsula, Mexico.
Hidden beneath layers of limestone and ocean sediment
lies a scar more than 100 miles wide.
It's the remnants of an ancient asteroid impact
that reshaped all life on planet Earth.
Today, it's known as the Chicxulub crater,
and it's believed to be the smoking gun
in a planetary murder mystery.
Chicxulub refers to a impact crater
that was made by, uh, an asteroid
that was about seven miles in diameter
that impacted our planet 66 million years ago
in what is today the Yucatán Peninsula.
This is the major cause of the mass extinction
that wiped out the dinosaurs.
And it's only been very recently that the first site
has been put forth as actually capturing that catastrophe.
[Shatner] The theory that an asteroid killed the dinosaurs
was only first proposed in 1980,
by Nobel prize-winning physicist Luis Alvarez
and his geologist son Walter.
The Alvarez hypothesis initially faced skepticism
in the scientific community,
but in 1991, opinions changed
when the Chicxulub crater was identified
as the ancient impact site.
And just how could one single asteroid
decimate life across the entire planet?
[McGee] A impactor came in with an explosive power
which is almost unthinkable.
Millions and millions of times stronger
than the strongest nuclear weapons ever built.
It would have been things that don't seem comprehendible.
It heats up the air around you to the point
that it can light wet vegetation on fire.
You've got shock waves traveling faster than the speed of sound,
leveling everything within a thousand miles.
A giant global tsunami thousands of feet tall.
And then, all of this material that was shot out into space,
fine portions of it end up circling the upper atmosphere,
and they start to block out the Sun.
And that is what kicks off the ecological disaster
that ends up killing 80% of the life on Earth.
[O'Connor] One thing I think is so fascinating
is that if this asteroid hit our planet a few hours earlier
or a few hours later,
it would have hit a different spot, right,
because the planet's always rotating,
and if it had,
it would not have caused a mass extinction.
It hit in a shallow marine shelf,
and in this shelf, you have all these sulfur minerals
that, when blasted up into the air,
then caused a chain reaction of events.
[Longrich] Temperatures plunge,
large parts of the world just start freezing.
and things that rely on sunlight,
things like plants,
uh, things like algae,
uh, that form that basis of the food chain,
they can't photosynthesize.
Basically, there's no more food left,
and the entire ecosystem collapses.
I think a lot of dinosaurs might have been able to hide out
in little burrows and try and survive the cold
and try and survive the fallout, but there's still
a lot we don't know about exactly how this went down.
[Shatner] While most scientists believe
a devastating asteroid impact was the sole cause
of the extinction of the dinosaurs,
it's far from unanimous.
Because around the same time, 66 million years ago,
there was also a catastrophic volcanic eruption
on a truly apocalyptic scale.
[Naish] Several other important things
were happening at the same time
as the Chicxulub impact event.
For example, we know that there was a massive outpouring of lava
in central India, resulting in incredibly thick lava deposits
known as the Deccan Traps.
People have often asked, could those
actually be responsible for the extinction of dinosaurs
rather than the Chicxulub impact event?
[McGee] The Deccan Traps were
a style of volcanism that we don't see today,
where you have a giant fissure open up
and huge quantities of gas and dust are released.
So, some have alleged that it could be that the asteroid
did it on its own, and it could be
that it had help from the Deccan Traps.
[Shatner] It's surprising to think that plausible theories
about an extinction event are recent discoveries.
But perhaps more shocking
is the consensus that our planet is still home
to living, breathing dinosaurs.
Birds are dinosaurs.
And every time a scientist said,
"Hmm, I think birds are living dinosaurs,"
they did so by studying archaeopteryx,
which is the oldest bird ever found.
The first one ever found was found in 1855,
and was only identified as an archaeopteryx, uh,
when John Ostrom came around
in, like, the late '60s, early '70s.
Archaeopteryx is the single fossil responsible
for our current understanding that dinosaurs are not extinct,
and that birds are living dinosaurs.
And I would argue that that's one
of the most transformative things
that we have learned about the natural world
in the last 50 years.
[Longrich] Birds are not dinosaur relatives,
they are the direct descendants of dinosaurs.
A handful of birds managed to survive
that extinction event somehow
and then radiate and give rise to all modern birds.
If you want to see a really primitive dinosaur-like bird,
probably your best bet would be either a chicken or a duck.
It's possible the early duck-like
and chicken-like birds may have lived alongside T. rex.
[Lance Geiger] In some ways, that's freaky.
I mean, a chicken bears a startling amount
of genetic comparison to a Tyrannosaurus rex.
That's just kind of amazing to think,
because you look at a chicken, you don't think
of the giant apex predator.
But there are certainly birds,
like the shoebill stork
or the cassowary, that are very large,
sometimes, you know, four, five feet tall,
which is kind of terrifying for a bird, right?
So, we're still in the era of the dinosaurs.
They're just, you know, now they're shoebill storks.
[O'Connor] The idea that birds are living dinosaurs
drastically changes how you look at animals alive on our planet.
But then, there is so much
we do not know about the biology of dinosaurs.
Like, very fundamental questions.
Like, okay, for example, take archaeopteryx.
There's features of archaeopteryx
that tell us this thing could fly.
But how it flew is a mystery.
It's a very fundamental question
that we still don't understand, and there's so much more.
Every other paleontologist you ask
is gonna have their own set of burning questions
that they are dedicating their lives to trying to answer.
For every question we attempt to answer,
we usually just create ten more questions for ourselves.
There is a lot we don't know.
Who would have thought that a chicken
shares the skeletal traits of a Tyrannosaurus rex?
So, if the birds we see each day
are considered "living dinosaurs,"
is it possible that other prehistoric species
may have survived and evolved
to become creatures of myth and legend?
[Shatner] The Great Wall of China, May 2024.
Along the Jiankou section
of this serpentine wonder of the world,
scientists from the Beijing Institute of Archaeology
discover the sculpture of a dragon's head
carved into stone.
For 6,000 years, China has revered
these powerful, serpent-like beings.
But where did the belief
in these legendary creatures come from?
[Naish] Throughout history, people have come up
with ideas about enormous, mythical,
predatory reptiles that have special powers.
They were able to fly
or they could breathe fire
or they were impervious to weapons.
And a really popular idea which just never goes away
is, surely, these stories about these creatures--
dragons-- surely, they're based on fossils.
Fossils like those of dinosaurs.
[Shatner] Could dragon legends trace back to ancient people
stumbling upon dinosaur bones and mistaking them for monsters?
It's a compelling idea.
But does it fully explain why dragon stories appear
in so many cultures separated by oceans
and thousands of years?
We can see the word "dragon" being referred to
different creatures at different time periods
in many, many different cultures around the world.
Uh, it shows up in the Bible.
And one place where you find a huge role
for winged feathered serpents in the divine sense
is in Mesoamerica.
Quetzalcoatl from the Aztec tradition.
Pretty much all over Central America.
And in here, I really don't think we can discount the role
that dinosaur fossils and other evidence of dinosaurs played.
Dinosaur eggs, for example.
Everybody knows what an egg is.
What happens when you find an egg that is clearly ancient?
So, these can influence an already existing story,
provide confirmation,
and really help increase everybody, uh, believing
that these things were real.
[Shatner] Discovering dinosaur fossils proves that sometimes,
extraordinary monsters really are rooted in real creatures.
While we know some dinosaurs did evolve into modern-day birds,
is it possible that other kinds of dinosaurs
are still hiding in the remote corners of our world?
For well over a century, legendary creatures like
the Loch Ness Monster
and Champ from Lake Champlain in North America,
were all connected to an ancient type of dinosaur,
or a marine reptile, known as a plesiosaur.
[John Rhodes] These are instances in which people have
sighted large swimming creatures that resemble a plesiosaur.
And we hear these repeated stories
over and over and over again.
Now, could they be real?
Could some sort of dinosaur aquatic life
during the dinosaur time have survived just like the birds?
Eighty percent of the oceans remain unexplored,
and so, what's down there?
Anything's possible.
[Shatner] Sightings of massive creatures
said to resemble dinosaurs
are more widespread than you might imagine.
In fact, it's believed that a ferocious predator
lurks in one of the last unexplored regions on Earth.
[Gerhard] From the remote Kasai valley
of the African Congo,
there are accounts of another type of dinosaur
that resembles a Tyrannosaurus rex,
and it's known as the Kasai rex.
Allegedly, it was encountered by a Swedish hunter
named J.C. Johanson back in 1932.
While on a hunting excursion, Johanson claimed
that he encountered this animal that was bipedal,
about 40 feet long,
reddish in color with black stripes,
and it was, in fact, attacking elephants.
And he claims that he took three shots at it...
...with only one shot connecting,
and it ran off into the bush.
And then there's the mokele-mbembe,
which means "the one who stops the flow of the river."
It's typically seen in the areas around Lake Tele,
the Likouala swamp, the Sangha River.
And it's typically described as about the size of an elephant,
a long, flexible neck and a long tail.
Now, this physical description doesn't match any known animals,
but it is almost an exact description
of a small sauropod type of dinosaur.
So, it almost seems as if
the African Congo really sounds like a lost world.
[Shatner] Could unidentified dinosaurs
really exist in the deep recesses of our planet,
beyond the reach of science?
For some, it's a distinct possibility.
And perhaps, long ago, the very same question was asked
about giant, fire-breathing dragons.
[Rhodes] You see the pictures of these dinosaurs,
and most of it's born out of our imagination.
It's not that fossil evidence gives us a clear answer.
They might have a few bones of a creature
and say, "This is what it looked like,"
and I think that's the same thing
that they did in ancient past.
They would look at the bones
and kind of have an idea of what it might be.
It may not be what they think it is,
but their imaginations and their cultures
believed that was the actual bones or fossils of a dragon.
Do medieval tales of dragons and other monstrous creatures
suggest that dinosaurs
could have lived much longer than we thought?
While it's possible that evolution
may have helped some species adapt and survive,
today, scientists are experimenting
with revolutionary technology
that could soon bring the extinct back to life.
[Shatner reads on-screen text]
Colossal Biosciences,
a genetic engineering company, and its partner,
announce they are the first laboratories in the world
to successfully sequence the entire Asian elephant genome.
This incredible achievement could allow scientists
to do something once believed impossible:
bring a prehistoric animal back to life.
[Geiger] Colossal Biosciences
wants to use genetic manipulation
in order to bring back animals that have gone extinct.
For example, the woolly mammoth.
We have examples that are frozen in permafrost.
And so, they hope that you can maybe
take the genes from a woolly mammoth,
you can gestate that in an existing elephant,
and you've recreated the mammoth.
[Lacovara] The woolly mammoth went extinct just about
3,300 years ago.
And to do something like
bring back the woolly mammoth,
has deep implications for medical technology,
it has deep implications for modern conservation.
So, I think, as a result of that,
we're going to see species that
would have gone extinct in the near future
be pulled back from the brink of oblivion.
[Shatner] Could it actually be possible
to bring back a woolly mammoth?
While it sounds like science fiction,
in 2024 and 2025,
Colossal Biosciences announced the birth
of three bioengineered dire wolf puppies,
a prehistoric species that went extinct
around 12,000 years ago,
after combining fossilized DNA with modern gray wolf cells.
And their fascinating work begs an obvious question:
will mankind one day resurrect a dinosaur?
So, de-extincting dinosaurs is not really possible
because the DNA is completely shattered
after millions of years.
It would be extraordinarily difficult to reconstruct it.
However, if one has complete control over genetic code,
theoretically, I imagine one could design any animal,
including maybe a dinosaur, that you could create.
It's not scientifically impossible.
It doesn't violate the laws of physics.
But that would be a choice for people to make
of what you bring back and what you don't.
[Lacovara] To be a dinosaur, you have to have
the first dinosaur for an ancestor.
It's the same reason that we're mammals.
We and hamsters and blue whales,
we all have the first mammal for an ancestor.
So, imagine this family tree,
and the ancestor is down at the bottom,
descendants are here.
Everything in that triangle is part of that group.
And so, if you have the first dinosaur
for an ancestor, you are a dinosaur.
Birds have the first dinosaur for an ancestor.
So, it might be possible, through genetic engineering,
to tweak the genomes of birds to get them to express
more of what you might call their dinosaurian traits
so that we could possibly create a facsimile
of a non-avian dinosaur.
[Shatner] Could we engineer bird DNA
to bring dinosaurs back to life?
And if so, how would that be achieved?
Well, some experts believe the solution already exists.
[McGee] There's a gene editing process
using what they call CRISPR,
when you try and edit genetic code,
and while the act of combining DNA
from different organisms may not itself be problematic,
there are several things that can actually go wrong.
Sometimes CRISPR will go in and delete or change things
that weren't supposed to be changed.
It's an accident.
Or there are also problems
where the CRISPR goes to insert the section of DNA
it's trying to insert in the right place,
but it overwrites too much.
[Vescovo] CRISPR, unfortunately, can be quite unpredictable.
The quality controls you must have are extreme.
We still don't quite know how many things work
at the molecular level when it comes to DNA,
cellular mechanics, tissues, all of these things.
This is all very new technology, and we're working through it,
but we're making lots of discoveries.
When we look at these scenarios of kind of playing God
and dealing with extinct species,
there are many scenarios where that could go completely wrong.
There are certain endeavors
that humans should perhaps not pursue.
As cool as it would be to see a living dinosaur,
it would be kind of a Frankenstein-type scenario,
where these genes are kind of manipulated
in weird and interesting ways.
[McGee] Some have alleged that, in trying to create
a species that was once extinct,
you're gonna create Frankenstein DNA,
a mishmash of genetics which is, in some way, unnatural.
But it's worth noting that we are all
Frankenstein DNA already.
Human beings share 60% of our genome with flies.
It's just code.
Things like, you know, the head should go on one side,
the-the legs should go on the other.
Once you accept the idea that we're already
Frankenstein snippets of code, of DNA,
the idea of turning around and swapping
little segments in and out
is suddenly a lot less alarming, I think.
[Lacovara] If we were to be able to bring back
ancient dinosaurs, that's a whole different thing
than, say, bringing back a woolly mammoth.
A woolly mammoth belongs in this world.
For species that went extinct in the near-term at our hands,
like the woolly mammoth, like the dodo,
We have a moral obligation to bring back
those creatures if we can.
This is their world, and they can still play
an important role in their ecosystems.
A T. rex, a Dreadnought, a triceratops,
has no place in this world.
It's not the kind of thing you would want to release
on the landscape.
I'm not sure it's a fantastic idea.
There may come a day when advances in genetic engineering
will resurrect a dinosaur.
But if so, could humans coexist with these mighty beasts?
Well, according to some,
it's already happened.
[Shatner reads on-screen text]
Heavy rains transform the region
as the Guadalupe River raises
26 feet in less than an hour.
Catastrophic flash floods sweep away homes,
vehicles,
and claim an estimated 135 lives
in the sixth deadliest freshwater flood disaster
in U.S. history.
But those raging waters also reveal a new window
into Earth's prehistoric past.
During 2025, parts of Texas
were severely affected by major flooding events.
And floods are bad,
they cause all kinds of problems for people and environments.
But one thing they do, which is of interest
to people interested in fossils,
is floods obviously scour away a lot of surface material,
like, you know, sand and rocks and-and such.
And as a consequence, they often reveal the bedrock,
rocks that you haven't seen before.
And a major flood event revealed a new set of tracks
laid down about 113 million years ago
made by a particularly big, impressive predatory dinosaur.
An animal called Acrocanthosaurus.
And the tracks are really pristine.
They look really great.
[Shatner] Texas has long been seen as a hot spot
for well-preserved dinosaur tracks.
In 1972, the Dinosaur Valley State Park
was established to protect some of the most
pristine fossilized dinosaur footprints...
...in the world.
[Williams] The Dinosaur State Park
is right on the Paluxy River,
which is outside of Glen Rose, Texas.
There's some beautiful examples of cerapods
and therapod dinosaur footprints there.
They've got prints going left, right, all over.
It's like a major freeway for all the dinosaurs
to come through.
But the interesting thing about this area
is that there's also man prints
that are inside of the... the mud strata,
or the limestone which is from the Cretaceous period.
So, about 113 million years old.
It's perfectly preserved.
It creates a broader picture and makes you wonder.
This is incredible.
So, I think there is something going on.
I think we need to do a little bit more evaluation
and we need to keep an open mind and we need
to examine the facts a little bit clearer.
So-- and of course, that builds the-the controversy, is:
did man coexist with dinosaur?
[Shatner] It's widely believed that Homo sapiens,
the first anatomically modern humans,
appeared around 65 million years
after non-avian dinosaurs went extinct.
But not everyone agrees with this theory.
Willie Dye, a lecturing archeologist
at the Creation Evidence Museum
believes the Paluxy River fossil site
provides clear evidence that mankind
once walked with dinosaurs.
I just really enjoy-- especially, working in,
in Glen Rose with the dinosaur tracks.
Eleven different species of dinosaurs there.
And human footprints all in the same area.
We've uncovered over 600 dinosaur tracks
and over 90 human footprints
in the same Cretaceous limestone.
You have the Delt track, with the Acrocanthosaurus
stepping into a human footprint.
That's one of the most famous ones that we have in there.
And then we've had, uh, evolutionists
that say, "Impossible."
That's-that's their word. "Impossible."
But yeah, you're looking at the evidence right there.
[Shatner] The theory that man and dinosaur coexisted
is related to an idea known as creationism,
which includes the belief that God created
both dinosaurs and human beings around 6,000 years ago.
It is not accepted by the scientific community.
But ever since dinosaur tracks have been found
in the Paluxy River over a century ago,
the site has been a popular destination
to see where some believe man and dinosaur
walked side by side.
[Williams] On the Paluxy River,
the prints were first found by George Adams
and his brother Ernest "Bull" Adams
back around 1908.
Even up into the 1930s, people were coming down there
to talk to Ernest "Bull" Adams,
and just to see the man prints
and the huge dinosaur prints that were alongside.
They were becoming so popular,
they started selling chunks and blocks
of these dinosaur prints to people.
And during the Great Depression,
people did what they had to to make money.
They were running out of prints to sell,
so George thought, "Well, I can make some money
if I carve up a few fake ones."
And that was a big mistake because
a lot of people now associate the Glen Rose formation
with these "fake" human footprints.
And he only made maybe two or three of them.
And those are the ones that did the most damage to this story.
But the prints that are available now
are slowly degrading because of carbonic acid in the rainwater.
It'll slowly destroy the limestone,
to the point where you can't tell if it's a dinosaur,
if it's a human footprint.
[Shatner] While the dinosaur footprints are genuine,
the alleged human tracks have been largely regarded
as manufactured or misidentified.
But should the idea be dismissed altogether?
Even the theory that the dinosaurs were killed
by an asteroid impact was only substantiated in the 1990s.
So, how can we say for certain that we know everything
about the timeline between man and dinosaur?
[Williams] We were always taught
in school that the dinosaurs were here
and they ended around 65 million years ago,
and then man came on the scene millions of years after that.
We need to keep an open mind,
and we need to examine the facts a little bit clearer
without having a lot of this idealism
that man was here at a certain time.
It deserves a little bit more attention
than we've been giving it.
[Shatner] Sixty-six million years ago,
an apocalyptic cataclysm
dramatically altered the course of life on Earth,
and killed all non-avian dinosaurs.
But what if an extinction event never happened?
What would dinosaur evolution look like?
[Naish] What would the world be like had
that mass extinction event not happened?
Would dinosaurs have evolved intelligence
similar to that of primates, or even humanlike dinosaurs?
And it was asked, most famously,
by the Canadian paleontologist Dale Russell,
who, in 1981, actually proposed
that had non-bird dinosaurs not become extinct,
they would ultimately have given rise
to big-brained humanoid dinosaurs.
And Russell actually worked with a model maker
to produce a reconstruction of what this creature,
this "dinosauroid," might have looked like.
And their creature looks suspiciously like a small,
green, scaly humanoid.
[Longrich] Dale Russell had this idea of a, a dinosauroid,
which is an intelligent, tool-using dinosaur.
It walks upright, it kind of looks like a human.
So, it seems like science fiction.
And yet, these get at some of the most profound questions
we can possibly ask about evolution.
[Shatner] Big-brained humanoid dinosaurs?
What would life have been like for these dinosauroids?
Would they have developed their own religious beliefs,
advanced technology or maybe even their own space program?
Or might they have taken another path entirely?
What if the dinosaurs didn't go extinct?
What might that evolutionary pathway have looked like?
The dinosaurs didn't really do anything wrong.
They were highly diverse, highly successful.
And then, cut down in a moment by, basically, a fluke.
And then the asteroid impact occurs and wiped them out.
And if it had veered off a few thousand kilometers
in a different direction,
missed the Earth entirely, they'd still be here.
One possibility is they might have evolved
into something like us.
But it may well be that dinosaurs
wouldn't have evolved intelligence.
They wouldn't have created civilizations.
I think a more likely scenario
is they kind of would have kept doing
what they were already doing.
That being said, we'll never really know.
So, it's a really profound question,
but it's very difficult to answer.
[Shatner] If non-avian dinosaurs had been given
more time on the planet, what might they have become?
It's a fascinating question,
but for now, the mystery of Earth's prehistoric past
and its magnificent creatures
is yet to be uncovered.
Now, it's fair to say that we're in a golden age
of dinosaur research, because more people are looking
for dinosaur fossils than ever before in the whole of history.
But one thing that we always emphasize
is that we are still just scratching the surface.
There are thousands of dinosaur species
yet to discover in all parts of the world.
What I love about paleontology is the mystery.
Looking at these fossil bones
of these creatures that lived
millions and millions of years ago,
I love how it's this intersection between
science and your imagination.
You'll be like, "Okay, this is my best
interpretation of the evidence,"
and then a few years later, a new fossil comes around,
and it shows you that you were completely wrong.
Evolution will produce something crazier
than we could have imagined.
Based on the fossil record,
we know with certainty that dinosaurs
walked the Earth millions of years ago.
And in a very short time, we've been able
to piece together an almost incomprehensible picture
of a thriving planet
that is unrecognizable to us today.
Yet, the truth is, there are countless
unanswered questions about Earth's prehistoric past.
So, while new discoveries and modern technology
may surprise us,
it's not hard to believe that the mysteries
of the dinosaurs will forever remain...
...unexplained.
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