Original subtitles

Around 50,000 years ago,

in a prehistoric forest of East Asia,

the first humans arrived from Africa to live and to hunt.

Just a few thousand individuals would become the ancestors

of all the people of East Asia, Australia and the Americas.

This vast land was thought to be empty

when they took their first steps here but now it appears

they were not alone.

This remote cave in Southwest China

is the final resting place of strange unknown humans.

Their remains had laid undisturbed for millennia

until a chance encounter brought them to light.

Now, we are faced with a shocking possibility.

We may have unearthed a new species of human.

- In a way, it's the sort of thing you wouldn't ask for.

What we faced here was a discovery

that challenged everything we understood

about human evolution.

These ancient bones may change forever

our understanding of where we came from

and what makes us human.

On a quiet mountain road in the Chinese province of Yunnan,

two men from very different worlds are on a journey

back in time.

Ji Xueping, a Chinese paleontologist

is traveling with Australian paleoanthropologist,

Darren Curnoe.

They're on their way south to one of the most important

archaeological sites in Asia.

- I've wanted to work in Asia my whole career.

I was at Asia these days where it's an amazing opportunity.

It's close to Australia that would help us understand

the origins of indigenous Australians

but also Asia in many ways seem to me to be

like a blank canvas particularly with the question

of the origins of modern humans.

Asia today has more than half the world's living population

but yet we know so little about their origins

and their relationship to people

in other parts of the world.

In 1989, mine workers accidentally

unearthed ancient looking human remains

at this site in Southern Yunnan.

They lay alongside bones of red deer

that once roamed this region.

Locals soon dubbed the site Maludong, the Red Deer Cave.

The mine's closed and the mysterious bones were moved

to a nearby museum.

There, they lay buried in the volts, unstudied

for almost 20 years.

Then in 2007, Ji invited Darren

to help investigate these fossils.

They were unlike any he had ever seen.

They were charred and strange and included part of a skull

with holes drilled into both sides.

- This is the most complete skull from Maludong

and it's also the one that has the most events

from modification, alteration by humans.

The entire base of the skull has been cut off,

chipped away using stone tools and then they've used

another tool to smooth the edges and to actually polish it.

To understand what this skull cut means,

they called in an expert in ancient human habits.

Cultural anthropologist Paul Tacon.

- Making of skull cups is a very modern form of behavior

and the Neanderthals didn't make skull containers,

all the other known examples past and present

were made from the skulls of modern humans.

Sometimes, these were made for use in ceremonies.

They sometimes were made from the skulls of enemies.

It was a way of insulting your enemy

by drinking from their skull.

Besides purposely shaping the edge of the skull

to make it into a nice container, two holes

were purposely drilled on either side

but not exactly in the center.

They're drilled close to the front of the skull

where most of the weight is.

So, the person who fashioned this was very ingenious.

They figured out that since there was more weight here,

put the holes closer to it,

it will sit nicely in the air without spilling.

For Paul, this was the handy work

of a sophisticated modern human,

but for Darren and Ji, the anatomy of the bones

told a different story.

- When we started to look at the remains in detail,

it actually became very unsettling

because they're just so unusual.

In many ways they just look so primitive.

The shape of the eyebrow bone is really unusual,

very prominent and the brain case itself is really low

and very rounded.

These look like they should be one or two

or maybe even 300,000 years old.

The enigmatic features of the Red Deer Cave

fossils post puzzling questions about human origins

in this part of the world.

To date much of the focus on human evolution

has been a long way from Maludong,

across the world in Africa considered to be the birth place

of our direct ancestors and the cradle of all humanity.

- So the first few million years of our evolution

were in Africa with this ape like two footed creatures

and they gave rise to Homo erectus.

Homo erectus is the first human like creature

to leave Africa.

It settled Europe and East Asia and survived in Asia

until about half a million years ago.

And we up here in the record, the fossil record

about 200,000 years ago

modern humans or Homo sapiens

and the subset of us left Africa about 80,000 years ago,

settled the rest of the planet

and gave rise to all living people.

The out of Africa story remains

the predominant theory for the origin of all human species.

- Well, it's overwhelmingly

an African European story.

I think it's fair to say that there's been a bias

in our work for almost 100 years where most of the work

has been done in Africa and Europe or most of the evidence

has come from those places.

As our ancestors colonize the globe,

they entered unknown territories.

In Europe, they encountered the Neanderthals,

our closest ancient human cousins.

But most anthropologists believe that by the time

modern humans arrived in Asia,

all previous human species there had died out.

Then in 2004 on the island of Flores in Indonesia,

scientists discovered fossils of an ancient creature.

No more than a meter tall and with a tiny brain.

Homo floresiensis revolutionized the long pound theories

of human evolution.

It came to be known as the hobbit.

- When the hobbit was found, many of us

just couldn't believe what was being proposed.

It was something that look like human like creatures

of three million years ago surviving until 17,000 years ago

in Indonesia are on a highland

with sophisticated culture.

It didn't make any sense.

- The hobbit really threw things up in the air

because that was the first of its kind

being something really completely outlandish being found.

Professor Bert Roberts was part

of the original team that discovered the hobbit.

- In the recent past, that was in the last few

tens of thousands of years, we thought it was

much simpler situation.

There's us Homo sapiens, there's Neanderthals

in Western Asia or in Europe and the rest of the world

was pretty much empty of other human species

and suddenly out of nowhere we got a brand new type of human

who's still surviving until very, very recently

and yet such an ancient design.

You think wow, if we can find this brand new species

just below the ground today,

how many are we missing out there?

Maybe we'll be misidentifying things in the past.

Maybe we just haven't been looking in the right places.

There are vast expanses

of unexplored territory across Asia.

Scientists have barely scratched the surface

of what lies beneath.

In 2008, Darren and Ji made their first journey

back to the Red Deer Cave.

- We didn't really know how the site was.

When we started working here, there were suggestions

that it could had been towards the end of the Ice Age

that there was a very little chance

that it could have been considered be older

and that was an exciting prospect, exciting opportunity.

When you start digging a site like this,

you're aware of the fact that you're actually the first

people to be exposing things from the ground.

You're the first people to see these things

since the people who actually used the cave

tens of thousands of years ago.

And it gives you a real connection to your ancestors

to the way that we lived for millions of years

in our evolution.

And there's always the excitement if you don't know

what's gonna be revealed by the next stroke

of the trail of the brush there.

And what was revealed

were layers and layers of ash.

- This ash is as fine as you would say

if the fire was built only last week.

It's really quite incredible.

The preservation is just extraordinary

and you can see pieces of charcoal

and these are in fact is actually burnt clay.

So it's soil that was on top of the fire.

It was so hot that it's baked it.

And when we look at the house we actually find animal bones

and animal teeth.

And so they've actually come in and they have cooked

particularly deer bones and then

they butch them on the side.

So these amazingly thick layers of ash represent huge fires

that were being built up in the cave over a period

about a thousand years.

It's probably the deepest ash sequence or half

that's been found in China,

possibly one of the largest in the world.

The Red Deer Cave was just beginning to reveal

fascinating glimpses in the Stone Age life in China

and that it all went wrong.

- My heart sunk when we found

what we thought was a bit of pottery.

Pottery is one of the most enduring

of manmade materials but it is a very recent innovation.

- I was hoping to find a site

that was tens of thousand years old.

Maybe a site that might tell us about the earliest people

in the area but instead I thought we'd found a site

that was only a few thousand years old.

We were feeling disappointed actually.

We thought maybe the site was just another

early farming site that maybe in fact it wasn't going to be

the site that might give us some real insights

of our understanding of human evolution.

But the mystery of the Red Deer Cave

was far from over.

Back at the museum, sacks of fossils collected

from the original excavation were pulled out of the coffins.

Until now they had been long forgotten.

- We really had no idea just how many bones

there were, how rich the site was.

There were bags and bags of these fossils

that had been removed,

that were just waiting to be studied.

When Darren and Ji examined the bones,

they were shocked.

- I've never seen a set of human remains

like this ever before.

Every bone that we looked at had been modified in some ways.

Some had been cut.

Some had been burned and others painted in ochre.

They've got these massive fires in the cave

and sometimes they throw on complete limbs,

entire body parts and other times it was part body,

sometimes even just the bones themselves.

When you find evidence for the burning of human bones,

you always think that there are two possibilities.

One of those could be cremation in some sort of ceremony

associated with burial or death.

The other of course is the very real possibility

that human remains were actually caught.

Could cannibalism be at the heart

of the Red Deer Cave mystery?

Within the cave's walls are whispering echoes

of a macabre event and clues

that don't make scientific sense.

The human remains from Red Deer Cave

had become a Stone Age mystery and this mystery

was about to get a lot more complicated.

In 1996 while moving artifact from a provincial museum

to its institute, Ji noticed a curious block

of rock on a shelf.

The rock had been discovered by a lone geologist

at a place called Longlin, 300 kilometers

northeast of Red Deer Cave.

It had sat on the shelf unnoticed for three decades.

- Ji said he had something to show me,

a surprise, a little present.

Ji was holding a rock that had a skull inside it.

I looked at it and thought what is this,

this look like something that could be hundreds

of thousands of years old.

Why is he showing me this?

What does he wanna do with this?

And that moment actually changed the course

of our research together.

They had just unlocked the door

into China's mysterious collections when Ji discovered

yet another forgotten fossil from the Longlin site.

- It was a big surprise because I didn't know

that there was a jaw but also they've been put together

in such a way that that actually made an artificial chin,

a fake chin look like a modern human.

And Ji and I studied it really carefully

and we actually found that the bones fitted together

naturally in quite a different way

and we had a very different looking jaw.

It would take two years of pain staking

reconstruction but finally the skull was liberated

from the rock.

It was the weirdest looking thing I've ever seen.

Darren is convinced it belongs with the jaw.

- What did I see?

Something I've made up.

I was confused, I was elated, I was perplexed.

It had this really bizarre mix of features, unexpected mix.

There were hints of modern human features.

There were these really ancient looking features.

In my own mind I didn't know

what I was gonna do with this.

This confusing mix of features

bears a striking resemblance to those found

in the fossils from Maludong.

- So we thought that the best way to approach this

given that we thought they were quite similar

was to have them in the same population,

have them as belonging to the same group.

Now, Darren and Ji are confronted

with someone or perhaps something

they really did not expect to meet.

They had come face to face

with the Red Deer Cave people.

This primitive looking creature once ran

to the prehistoric forests of Yunnan.

The question is, just how long ago?

- That face, I mean that's not

a modern human face, that level of projection like that

is what you see in Africa maybe two million years ago,

one and a half million years ago.

That's not--

To make sense of these archaic

looking fossils, the team needed to find out

how old they were.

Luckily within the cavity of the skull

embedded in the rock, they discovered

tiny pieces of charcoal.

These, together with charcoal remnants of the ancient fires

at the Red Deer Cave was sent for radiocarbon dating.

- I was sent the dating results

and I didn't believe the numbers.

I got on the phone, I rung my colleague and I said,

"Are you sure these are right?"

The Maludong fossils were just 14 1/2

thousand years old and the Longlin skull

was even younger, only 11 1/2 thousand years old.

- I couldn't believe it.

I was absolutely flabbergasted.

In fact, I jumped out of my chair

and I was jumping around the room like a kid.

This means that the Red Deer Cave people

were alive at the same time and in the same place

as modern human hunter gatherers.

- There Red Deer Cave people are unlike any

modern human we've seen before

whether 150 or 150,000 years old.

This means they're either very unusual modern humans

or perhaps belong to a different group,

different species but they're not us.

The suggestion of a new human species

is arguably the boldest statement

an evolutionary scientist can make.

In March 2012, the team take a daring step

to publish this possibility.

Distinctly odd fossil evidence found--

The so called Red Deer Cave people

had flat faces with bore noses.

Even though a computing picture it does--

It wouldn't be the first discovery

that's led to debate over whether a scientist

has found a new species.

I'm a little skeptic about the last one.

But they're reluctant to call it a new species

just yet and some other experts have their doubts.

- In a way, it's the sort of thing

you wouldn't ask for because it's so challenging,

so confronting.

The fact that they were just so weird and so young for me

was exciting but I knew I faced a big challenge

to convince my colleagues the significance

of what we'd found.

In the world of paleoanthropology,

the same fossils inspire radically different interpretations

among scientists depending on which school of thought

they belong to.

It's been called a science

of exquisitely informed speculation.

- Nobody looks at a fossil

with a completely open mind.

I suppose to some extent also we see what we think.

So, you come to a fossil and you have an idea

about the way you think in evolution worked

and the first thing you do is try and fit that fossil

into your world view.

I think that's human nature.

This is a science which struggles

with possibly the biggest questions of all.

Who are we and what makes a modern human?

For the past 30 years, our understanding

of what sets us apart from other human species

has perhaps been most influenced

by paleoanthropologist Chris Stringer.

- If we look just at the morphology, for me

everyone alive today share certain features in the skeleton.

So we have a high and rounded skull.

- When we look at the Longlin skull

and we look at the forehead, we can see that it does have

some modern human like features.

So, it has a forehead that arcs backwards, curves backwards.

- We have a small face tucked under the brain case.

- And the face is actually quite short like a modern human.

- We have a chin on the lower jaw.

We have a lightly built skeleton.

So these sorts of features are shared around the planet

and for me they diagnose

what a modern human is anatomically.

- So there are a couple of modern human features

but then there are all these features

that are really very ancient.

If we have a look at the lower jaw,

this really important feature that we see in modern humans

have a triangular chin is actually missing.

We can't see it and the teeth are massive.

On top of that, it also has some unusual,

some unique features that are found only

in the Red Deer Cave people.

So it has quite a prominent brow

and the cheeks are incredibly flat

and they flare out to the sides of the faces,

they curve around the skull.

And when we put them together and we see

that it has this massive jaw that the two jaws together

sit well forward to the face and that's really unusual.

Certainly for modern human it's a very ancient feature.

These bones aren't modern

and they're not meant to be around at that time

but yet they are.

14 1/2 thousand years ago, Southwest China

was released from the grip of the Ice Age

and filled with lush forested basins teeming with life.

This was the world of the Red Deer Cave people.

This was a land of the oldest

and most isolated mountain peaks,

the deepest valleys and the biggest rivers of all of Asia.

It was a landscape that had an indelible impact

on its people.

Could this hotspot of human diversity

have given rise to isolated groups that looks so different?

- What's actually led to the unusual features

on the Red Deer Cave people we simply don't know yet

but one possibility is that it was the development

of a population that was isolated

that had particular environment conditions,

maybe a particular kind of diet required,

stronger jaw muscles which modified the face.

That's a possibility.

There could be environmental features which change

the shape of the skull and on the body.

Could the Red Deer Cave people

simply be modern humans who have moved back

into more primitive looking beings

because of something in the water?

- In evolution we call that a reversal.

Time precedent in human evolution.

There are no other examples that I can think of,

of any human group that was isolated

for tens of thousands of years and then

suddenly it's anatomy emerged after that time

to look like ancestors of hundreds of thousands

of years ago.

In my understanding in my experience it runs counter

to our understanding of seven million years

of human evolution.

The problem for me is that if they're modern human

and they lack so many features,

so many characteristics of modern human.

So if we say okay, maybe they're early,

very early modern human, very primitive modern human.

If that's the case then why aren't they

100,000 years old?

As Darren and Ji pondered the puzzle

of the Red Deer Cave people,

other scientists offer their own explanations.

- Chris Stringer and other people who suggested

it could be hybrid.

- I think the Red Deer Cave finds are extremely important.

I don't think they represent a distinct species from us

but they really do document the variation

in modern human populations in the last 50,000 years.

Chris Stringer is the architect

of the out of Africa theory and firmly believed

that modern humans replaced all other ancient species

as they migrated across the world.

- My view was we had a recent African origin

and that could be virtually 100% of the story.

But what we've learned in the last few years is

that there was indeed some interbreeding

with the Neanderthals, with people over in

the far east called the Denisovans

who we've only really learned about

in the last couple of years from their DNA.

In 2010 in another remote cave

nestled within the Altay mountains of Southern Siberia,

ancient DNA was found, preserved within a finger bone

and a single tooth.

From these tiny fragments, scientists decoded

the entire genome of a new group they called the Denisovans.

- Not only we have this new species Denisovans

in Southern Siberia but the Denisovan DNA turns up in people

in Melanesia, Papua New Guinea and areas like that

and appears on Australians.

The fact you've got Denisovan DNA persisting

in modern day people means there must have been interaction

between that kind of ancient human and Homo sapiens

to get it in to our genome at some point in time.

So the reason why you can have archaic

human surviving in other places too.

- Since we know there was interbreeding

with ancient humans, perhaps some of these features

are reflecting into breeding in the past.

Maybe in China, the same thing could have been happening

with the Red Deer Cave people.

In terms of modeling, have interbreeding happen,

I mean obviously we don't actually know

and it could range all the way from peaceful encounters

where they traded with each other and exchange mates.

That's one possibility.

The other extreme is a group will run after the mates

and they will raid another area and steal some women.

These encounters have left their mark

within us today, hidden in our genes.

- There are suggestions that certainly

in the immune systems, modern humans have picked up

some of the bits of DNA from these archaic people.

So imagine modern humans evolving in Africa

coming into new environments with new diseases,

new pathogens and so on.

By interbreeding with the locals, they could get a quick fix

in picking up some of the immunity which those populations

would have evolved over hundreds of thousands of years.

Could the Red Deer Cave people

be hybrid offspring of modern and ancient human parents?

- Hybrids are really complicated question.

To diagnose a hybrid, you need probably to have DNA

from Maludong and Longlin fossil

but also you need DNA from both of the parent specie.

So, if we assume one is us, one is modern human.

Who's the other species?

I'm not convinced that interbreeding has been

unequivocally established.

It's an interesting idea and I think there are some

compelling, maybe persuasive evidence

but it's far from open and shut.

To try to untangle the genetic origins

of the Red Deer Cave people, Darren and Ji send samples

of the burned bones for DNA testing.

Ancient DNA science unlocked the genome

of the Denisovans from their remains preserved

in an icy corner of Siberia

but the Red Deer Cave fossils

are a different challenge all together.

- Fossil DNA is not easy to work with

because the bones have been buried for many, many years.

So especially for this sample, they're very

nice, hot and readily humid area so those conditions

are not good for ancient DNA storage.

Professor Su Bing is one of China's

leading geneticists.

A decade ago, he led the team that mapped the DNA

of over 10,000 living East Asians

in search of their origins.

- From this data, what we saw

is a very simple conclusion.

We all came from Africa, we all have African ancestors.

But not all scientists accept

this genetic evidence.

There are those that promote what is known

as multiregional theory.

They believe that instead of old members of our species

coming out of Africa, some modern humans

evolved out of Asia.

To explore this theory, Darren and Ji traveled

to nearby Guangxi province.

Here amongst this spectacular limestone landscape

lies Zhirendong, the mysterious cave of the Homo sapiens.

In 2007, Professor Jin Chang-Zhu and his team

unearthed two archaic human teeth here.

A year later, they discovered something

even more remarkable.

The primitive jawbone was found to have some striking

and unexpected features.

A protruding chin is a defining modern human feature.

When they dated the fossils, they found they were over

100,000 years old but the conventional theory

holds that the earliest modern humans arrived from Africa

around 50,000 years ago.

This would mean that modern humans were here

50,000 years before they were supposed to be.

This is the heart of the biggest controversy

in the science of human evolution.

The idea that modern day Chinese are descended

from a separate evolutionary line to the rest of the world.

- In China, they believe that the Chinese

Homo erectus fossils are their direct ancestors

and they can see in their interpretation

a continuative evolution in terms of morphology

and behavior from a million years ago through

to present Chinese populations.

I gave a talk there in the 1990s on the Out of Africa theory

and it didn't go down very well as you can imagine

and I was told that they knew they were evolved

from Peking man.

It was almost like an act of faith.

- I think they’ve demonstrated that modern humans

got to East Asia much earlier

than the genetic evidence would suggest.

- I think that's very important.

Ji believes that the Zhirendong fossils

are proof that modern humans in this part of the world

evolved here in East Asia.

Whichever theory prevails, Darren sees the find

as an important clue as to the identity

of the Red Deer Cave people.

- What's impressed me about the Zhirendong jaw

is that is does seem to have a human like chin.

You don't see a human like chin

in the Red Deer Cave people jaws.

The Red Deer Cave people don't look very modern

in comparison.

I think if Zhirendong do represent an early modern

population then the Red Deer Cave people can't be.

But the hunt for fossil DNA that could

confirm this has been unsuccessful.

- Unfortunately we haven't got any positive result.

We didn't get any DNA.

- There's very little biological material

left in the bones and teeth from Maludong.

This is because they've been burned

to such high temperatures.

What it means unfortunately is that there's really no chance

of getting DNA from them.

Despite the lack of DNA, Darren is convinced

that the bones speak for themselves.

He's driven to the only conclusion that makes sense to him.

- After five years of working on this big puzzle,

this conundrum, losing sleep, traveling to and from China

to check and recheck.

I placed these fossils into what we know,

what we understand about human evolution.

I just can't see that they're anything

other than a new species.

It's an idea bound to create shock waves

throughout the scientific world.

- Science is very conservative.

So when people find new things that don't fit into current

widely held models where they come up with new theories,

they're challenged, they're ridiculed.

Sometimes their careers suffer.

- As soon as you make some announcement

that's unexpected, there's always gonna be detractors.

I mean, why would there be a new species

of human surviving in mainland China

until be on the last Ice Age.

- Yes, it's risky.

Of course it's risky but in a way

if you're gonna be honest and true to science

then you've got to be prepared to stand up and say,

"This is how I see the evidence."

It's a challenge to conventional wisdom

but then that's how science progresses,

that's how we improve our understanding of the world.

In this case our own origins.

Darren and Ji are preparing to show

the Red Deer Cave fossils to a scientific heavy weight,

someone whose judgment could either confirm

or quash their own opinions.

Jeffrey Schwartz is one of the few scientists in the world

to have studied virtually the entire human fossil record.

- Here professor.

- Wow.

Gosh, the actual things.

Can I touch?

- You're welcome to.

- That will be super.

So you think that surface has been modified?

- There's some cut marks.

- Right, I see that one,

holes in either side of it.

But then you got to break and then you have to change

in the plane of the bone and that's what's diagnostic.

- Here's an occipital fragment

and I can't find any muscle marking

on it. - Nothing.

- Nothing at all. - Nothing.

- Meet Longlin.

- Oh, there it is.

Okay, so what's interesting is the shape of the frontal

so different.

One thing that's very prominent is that you have this

huge muscular tuberosity.

You would actually see some kind of more verticality.

- That's right, absolutely.

This unusual shielding here in front.

- Yeah, oh I see what you're saying.

There’s only one specimen I know of

where the cheek region flares out like that

and it's one specimen from about 1.65, 1.7 million years old

from East Africa.

It's one of those unusual things in the human fossil record

and it certainly isn't like any living human I studied,

any human skull that I've studied

and I've studied thousands of them over years.

Certain features of the face here,

you don't see in any living human.

I would call it a different species

but I know that sends off a lot of

alarms and stuff but I think it's a different thing.

- We agree.

- This is really one of the top

paleontological experiences in my life.

- Fantastic, good.

Fixed our work.

I felt as though this cloud of doubt that I'd had

about my work, my ideas for the last five years

to suddenly lifted and then I had actually

for the first time some real independent support

and verification of what we found.

It was absolutely thrilling.

- The big shot, Jeffrey, Professor Jeffrey are coming

after today's check.

We don't want to move to another project,

move to another set.

I want to continue because it was daring,

we should continue this research,

more productive in the future.

- So the Red Deer Cave people could be the youngest

non Homo sapiens that we found anywhere in the world.

They're also in East Asia which is an area

that we thought was actually uninhabited

by the time modern humans settled the area.

We've always thought that modern humans,

Neanderthal share a common ancestor 400,000 years ago.

One of the implications of the Red Deer Cave people

was that maybe there was a branching event later on

that in fact maybe a group batted off the line

that was leading to Homo sapiens two or 300,000 years ago

and that that group is something like

the Red Deer Cave people,

a group that's almost us but not quite us.

It's an astonishing concept

to imagine a coexistence of two human groups

that are so similar but also so different.

What would their first encounter have been like?

This wasn't simply a different tribe.

This was another creature all together.

- What discovery means is that

when modern human left Africa that it wasn't just

the Neanderthals that they encounter.

In fact they met up with the Denisovans,

they met up with the Red Deer Cave people.

It's not just a scenario of superior modern humans

leaving Africa and taking over the world.

In fact, they had to fight for it that it wasn't an easy

process and that they were very complex interactions

along the way.

There's the possibility I guess

with the Red Deer Cave people.

We interacted with them.

What sorts of interactions were there

is the obvious immediate in the landscape competition

maybe lead to break with them.

Maybe we inherited aspects of our behavior

and culture from them.

Could that interaction have shaped our own evolution?

- What's significant about the Moludong specimens

is they really demonstrated the existence at the same time

of different species with our species Homo sapiens.

And then I think the ultimate question is

why did they disappear?

How did they disappear and why

were the only species still around?

There is one clue.

We know the Red Deer Cave people was still surviving

at the dawn of the greatest revolution

in the history of human kind.

- Beginning about 20,000 years ago,

modern humans began agriculture.

As agriculture developed, it was changing

the people who were engaging in it.

Their rituals, their relationships to the land,

eventually to even their morphology

but also they began changing the land through farming.

That may have severely impacted on remaining groups

of Red Deer Cave people who were true hunter gatherers.

- The farming revolution led to a whole

sweet of new diseases being experienced by people.

It was the beginnings of the population explosion

that we think about over the last few thousand years.

Worldwide there were maybe a handful of people,

several million people living as hunter gatherers

and in a fairly quick period of time that double treble

to the point where we've now got seven billion people

living across the planet.

No other site in the world has a cave human remains

that are dated to around the time that farming is beginning

and it does raise the possibility that the invention

of farming may have bumped off the Red Deer Cave people.

- If you look at recent human history

what you see is as the settlments increase in number

and density of human warfare to like increases.

And in terms of nature, we're the only really

bellicose or war engaging species

and it may not be a pleasant thought to think

that we're the cause of the extinction

of these very recent species that were our relatives.

Whether it was shear bad luck

or forces of a different kind, the Red Deer Cave people

may have been the last of nature's experiments

before modern humans were left

as the lone surviving human species.

As to the faith of those individuals found inside the cave,

there are clues hidden in the charred remains.

- One of the key questions that we ask

when see burnt human bone is was it cannibalism?

So we look closely to see the nature of cut marks

and fracturing and burning.

If we look at this material, we find that there aren't

many cut marks like you would expect if the meat was cut off

and after cooking in the fire.

What also is really unusual that we never see

with cannibalism is that after the bones were burnt,

they were painted with ochre.

Now, if this had been simply used for food,

the bones would had been discarded

and we would see burning but not ochre.

But with many of the pieces from Maludong, we see both.

So, I'm convinced that there is a form of burial practice

happening rather than cannibalism.

- This is probably a really special place

for the people who were occupying the cave

and coming here performing ceremonies,

putting large fires.

They were cremating probably their relatives,

maybe people who are important in their group.

And then later their bones were cut

and painted with red ochre,

so they had special value to them.

Until now, modern humans are thought

to be the only species that have made skull cups

and painted the bones of their dead.

- That's one of the fascinating aspects

of the archaeology of Maludong is there are a number

of different forms of what we would call

modern human behavior that appear to have been practiced

by another species.

These were intelligent compassionate people

who perform special rituals for their dead.

They mourned to their dead.

They might even have had a concept of the afterlife.

These people, whatever species it was.

They were not that different to us

and that tells us we are not unique.

But there is an alternative explanation

for what happened inside the Red Deer Cave.

The fossils reveal yet another twist

in this unfolding mystery.

- There is more than one Hominid on this table.

More than one Hominid for sure.

- What he actually said was pretty remarkable.

He actually suggested that we may have

three different species in the fossils.

Us, modern humans and then two brand new

previously unknown archaic species.

This would be one of the only sites that's known

in the world where you got three distinct groups

using the same place.

- The other conclusion that can explain this mix

is that it was actually modern humans

engaging in the modern human behavior

with the remains of the Red Deer Cave people.

Why were modern humans doing this?

What was the relationship with Red Deer Cave people?

Was it a close one and were they honoring

the dead Red Deer Cave people

or were they driving them to extinction

and purposely killing them.

It is an incredible story no matter

which hypothesis we ultimately accept.

We may never fully understand

what actually happened inside this cave.

All we really know is that the Red Deer Cave people

were once here and now they are gone.

- For me one of the profound implications

of the Red Deer Cave people is that here's a group of

humans that are us, they're almost us.

They share some characteristics with us.

It forces us to rethink the space that we've created

for ourselves as humans the way we've identified ourselves,

the way we think, we interact with the world is narrowing.

So, it forces us to rethink the concept,

the very basic idea of what it means to be a human.

It's important philosophically because it challenges

the concepts that we apply to ourselves,

the way we define ourselves,

the way we think about our place in nature.

I think it alters that.

Hi.

- Hello.

- Darren, hi.

- Hello, Darren.

- Wow.

- I'm Craig. How are you?

- I'm very fine, absolutely stud.

You're real.

- I know.

- My Red Deer Cave person, you're real. An amazing thing to see,

the bones feel like come to life, flesh real in front of me.

There's this new evidence from China of a distinct group,

probably a new species living in the landscape,

sharing the landscape with people just like us.

When you discover new species, you decide the name

and one of the names that we've talked about were proposed

with Chinese colleagues is Homo mituanas.

And mituan is actually Chinese for enigma or great puzzle.

- Mystery.

- So we think of you as our enigma man.

- Enigma man.

We are only just starting to piece together

this story of millions of years of our evolution

from fragments of bones and stones.

- Every culture has creation or origin stories.

What's different here is that we're weaving a story,

a narrative from scientific evidence.

Everybody cares about where they came from

and the place of humans in the natural world,

where we fit in the Cosmos.

This is the ultimate story for us.

In the 21st century, our sense of ourselves

as a superior species still informs so much

about how we relate to the world around us.

- It was simple when it was just the Neanderthals

because we could demonize them or make them out

to be primitive cavemen, dumb

and we were the smart ones, we got out of Africa,

we conquered them but it's not that simple anymore

because there are Denisovans,

there are the Red Deer Cave people.

There's the hobbit.

Suddenly, we're not this incredibly smart group

that was destined to take over the world.

It's not like that.

The Red Deer Cave people may be

the closest members of our diverse human family

to have walked amongst us.

- For most of the 7 1/2 million years

that we've been evolving, we've shared the landscape

with other human like creatures.

We competed with them for resources.

We occasionally had sex with them.

Today, that's not the case.

We find ourselves alone but yet the Red Deer Cave people

show that just 11,000 years ago we weren't alone.

Why is that the case?

This is the ultimate question for us.

Why are we alone today?

Perhaps the greatest legacy of our long gone

ancient relatives is how they remind us of our incredibly

good fortune to be here at all.