Nova (1974–…): Season 42, Episode 13 - Dawn of Humanity - full transcript

What makes us human?

Where do we come from?

Ever since Darwin
put forward the idea

that we evolved from apes,

scientists have wondered
about those first creatures

that left the ape world
and crossed into ours

In the last 50 years,

fossil finds have filled in
some of the many blanks

in the story of our evolution

But the bones of our ancestors
are few and far between,

allowing only glimpses
of how we slowly changed



over millions of years

from ape

to human

Now, in South Africa,

in caves dangerously deep
underground,

two new species of hominin,
our human ancestors,

have been found

There it was,

right there:

one of the most spectacular
early hominins ever discovered

lying on the surface of a cave

And not just a few
bone fragments

It's everywhere

Here, there are thousands



It's just absolutely incredible

the amount of bone
that's coming up

Oh, beautiful!

The first thing that
came through my mind

was Howard Carter's anecdote

about opening Tutankhamen's tomb

It was Lord Carnarvon in the
back saying, "What do you see?"

And Carter says,
"Things, wonderful things"

We have found
a most remarkable creature

and a most unexpected one

So we need a new kind
of language to talk about this

These bones could finally bring
our past into focus

What story will they tell
about how we became human?

A new light shines
at the "Dawn of Humanity,"

right now on this NOVA/
National Geographic special

The high plains to the northwest
of Johannesburg

have been called
the Cradle of Humankind

In the 1930s and '40s,
fossil finds here gave us

the first important glimpses
of our earliest ancestors

Then, for decades,

the discoveries seemed to dry up

It looked like
the Cradle of Humankind

had little left to offer

Go get 'em, good luck

Happy hunting

But now, from deep caves
in the Cradle

come two new discoveries

that could reshape
the understanding

of our ancient past

What is it?

It has teeth

It's so solid!

There aren't just
hundreds of bones;

there are thousands of bones

I had never seen or dreamed

of anything like the richness
of this site

Bones that may end up
illuminating

a critical million-year period
in our evolution

that has long been a mystery

There's a big gap
in the fossil record

with only a few little fragments

The fossil record suggests that

in that gap
lies the dawn of humanity:

the birth of the genus Homo

It's perhaps
the least understood

and most important episode
in our evolution

Before it was the world
of Australopithecus,

an ape-like creature
with a tiny brain

Lucy is the poster child
for the Australopiths

She walked upright, but belonged
to the world of the apes

If I were to see
an Australopithecus

at the end of a football field,

I would probably call the zoo
and say,

"Hey, an ape has escaped"

The upper part of the body

in Australopithecus is,
in general way, ape-ish

Go down, look at the pelvis,
very human-like

An Australopithecus
is sort of like a bipedal ape

If you went back in time

and saw them
walking around the savannah,

you would see animals that
stood up and walked like we do,

but they would've been smaller
in body size

Their brains
wouldn't have been as big,

so their heads
would've looked smaller

Their jaws and teeth
were very large

The fossil record suggests that

somewhere between two
and three million years ago,

these ape-like Australopiths

evolved into the first
recognizably human species:

Homo erectus.

They have big brains
and small faces,

adaptations for using tools

If I were to see, say,
Homo erectus

at the other end
of a football field,

I would probably call 911
and say,

"Oh, there's a wild man
over here,

and you know somebody should
put some clothes on him"

So what went on
in the transition

from Australopithecus
to Homo erectus?

For years, the only species
that filled that gap

was a creature called
Homo habilis.

But so little of it
has ever been found,

the origins of the genus Homo
have remained an enigma

The greatest mystery
facing paleoanthropology today

is to try to understand how,
when, where the transition

from Australopithecus to Homo
occurred

And what we don't know
is what happened

between Australopithecus
and early Homo

That's one of the big mysteries
right now we're trying to solve

The prize would be to discover
fossil remains

that could tell us about
that mysterious transition

And now,
they may have found some

There you can see two foot bones
in articulation

Emerging from ancient caves
in South Africa

are fossil finds
of astonishing richness,

and not just fragments,

but virtually complete skeletons

From the very first block
that we had,

we had a portion
of the mandible, the lower jaw,

and we had a collarbone

and one of the bones
of the forearm

So that was really,
really exciting

She's in there

We have a skull,
we have a mandible,

we have a complete scapula,
we have a complete clavicle,

we have a complete arm,
a complete hand,

and half of the pelvis,
which we can,

with reconstruction,
make into a whole pelvis

Will these skeletons
live up to their promise,

offering us a new understanding
of the dawn of humanity?

In August 2013, South African
Pedro Boshoff was out of work

He had been a soldier,
a prospector, an adventurer,

and even a part-time student
of human origins

Now he wondered
if he could earn some money

doing what he loves most:
fossil hunting

Towards the end of August,

I approached
Professor Lee Berger,

asking if there would be
the possibility

of a position at faculty
with him

Pedro Boshoff
came into my office

and said, you know,
"I really need work,

"and I have
the same belief as you

that there is more out there"

Lee Berger started exploring
the area of South Africa

known as the Cradle of Humankind
in the early 1990s

After 18 years of searching,

he had found only a few
isolated fossils

That's not unusual in the field
of paleoanthropology

These early human fossils

are probably the rarest
sought-after objects on earth

We in paleoanthropology
sit in one of the few fields

that probably have more
scientists studying objects

than there are objects to study

In fact, the vast majority
of people who do what I do

will never find a single piece
of one of these early humans

And if they do, it's going to be
an isolated tooth

Probably 80 to 90% of our record

are just little bits
of isolated teeth

Just to the northwest
of Johannesburg,

the Cradle of Humankind
is riddled with limestone caves

Some have already yielded
fragmentary fossils

of our remote ancestors

Lee was convinced there were
more discoveries to be made

I had known Pedro for 20 years
and I said, you know,

"Go out there,
enlist your caving buddies,

get underground, and see
if you can find something"

And so I bought Pedro
a motorcycle

so he could move around out here

Basically what he wanted me
to do

is to go through
the Cradle area,

locating and finding fossils

So I sat as I often do on a rock

and I contemplated
how I'm going to approach this,

and then it dawned on me:
I'm part of a caving society,

having caved in this area
for years

And in there,
I found Rick and Steven

I asked them to systematically

work their way
through caves and holes

towards the east of the Cradle

while I was busy working
in the west

We often don't look

in the places
that are most familiar to us

because we think
we know them well

I call it backyard syndrome

And so I said, you know,
"Start right under our noses

Go to the most
well-known places"

On September the 13th, 2013,
Rick and Steve decided

to look into a cave system
they thought they knew well

It's called Rising Star

It's an amazing cave

It's got a bit of everything

There's tight squeezes,

some great climbs,
beautiful formations

Rick and Steve headed
deep underground

I wanted to show Rick
a great climb in the cave

called the Dragon's Back

We climbed up there

And in the process
of taking some video

of the formations
at the top of it,

Rick wanted to get past me

So I went down
a small little crevice

basically so that Rick
could crawl over me

I was just getting
out of his way,

and as I went into it,

I noticed that there's still
a little bit continuing down

Once in the crevice,

Steve realized there was nothing
below his feet

He squeezed himself further down

Every time you go down,
it just goes a bit further

and a bit further
and a bit further down

You squeeze your body in
so that you don't slip

and you feel around for a grip

So my legs were dangling down
this last little bit

and you don't feel anything
below you

And the only way to climb down

is actually to lower yourself
as far as possible,

just keep on lowering yourself
until you're literally

your arms are almost
fully stretched out,

and then you start to feel
a couple of rocks

that you can actually
put your feet on

He emerged
into an hidden chamber

He called for Rick
to come down and join him

They could see massive rock
formations above their heads

But the real discovery
was beneath their feet

The floor of the cave
was littered with small bones

We saw at first one bone
lying around

We looked around a bit more
and, well, another bone

We actually spotted teeth
in the rocks

and realized
we actually had found something

Followed by a skull
in the ground

And finally,
one of the most interesting ones

was a mandible
with four teeth in it

Rick and Steve had no idea

what type of bones
they were looking at,

but they seemed intriguing

They took pictures and decided
to show them to Pedro

And I will never, never forget

when he came to me
with his photos,

put it on the computer,

and the first thing I noticed
was the jaw with the teeth

And I realized
this is definitely a hominin

So needless to say,
I called Professor Berger

He didn't answer his phone,
and we decided

we're going to drive
to his house

because now we're all excited,
bubbling, of course

Arriving at his home,
I rung the bell

and when he answered,
my words to him was,

"Lee, you really want
to talk to us!"

Pedro says, "You're really
gonna want to let me in"

And, you know,
9:30 at night, and it's dark,

but I could hear that emotion
in his voice

They flipped open a computer,
and I saw something

I don't think I ever dreamed
I would see

on a computer screen

A lot of swearing at first

Apparently that's his reaction
when he sees fossils

But yeah, he immediately
identified it as a hominid

That was a mandible

of what was clearly
an early hominin,

the teeth just perfect

The next picture
had a skull in it of a hominin

I could see it in outline

There were bones everywhere

They'd take

Every one of them
I could see in the image

were hominin

I was a bit in shock

because it all went like
a car crash for me, you know?

It really did, black and white,

and I have only visual,
not audio

Hominins are all creatures
in the human evolutionary line,

including Australopiths,
Homo erectus, and us

When his shock faded,
Lee immediately turned his mind

to the question of what type
of hominin this might be

From what he could see,

Lee thought it was
a single individual,

probably one of those
Australopiths

that came on the scene
some four million years ago

The photos were hard to make out

Lee wanted to know if the bones
in the Rising Star cave

were similar to fossils he had
discovered five years earlier

That was in a different cave
just ten miles away,

also in the Cradle of Humankind

It was Lee's first big find

The story all began
on August the 1st, 2008,

when I came into this valley
following targets,

which were these trees
above my head

that I could see on Google Earth

I walked up that old
lime miners' track way,

which wasn't quite as clear
as it is today,

mostly overgrown,

and I came into this grove
and found this little hole

The little valley
was called Malapa

Lee thought he knew it well

It was a Friday

Lee's nine-year-old son Matthew
and his dog Tau were with him

I stood at the edge of this pit
and I said, "Go find fossils"

With that, Matthew raced off
into the bush here

I thought he was going
to go chase giraffe or zebra

or something like that
with Tau in tow,

and a minute and a half later,

he shouted,
"Dad, I found a fossil"

Sitting right over
by that lightning-struck tree,

he had stopped and found
a little rock,

and I almost didn't go and look

because I knew he had found
an antelope fossil

because that's pretty much
all we ever find

I saw a fossil

I didn't think it was a hominin

I just thought
it was an antelope

because we find
thousands of those

I started walking
towards him though

because I had to see
what he had found,

and five meters away,
I realized that

sticking out of that rock
was a hominin clavicle

I couldn't believe it

I took the rock in my hand
and I was turning it,

trying to think
what else this could be

And as I turned
the back of it over,

there sticking out of the back
was a mandible and a canine

That's when I realized

that an extraordinary thing
had taken place

After almost 20 years

of searching
in the Cradle of Humankind,

Lee finally had
a major discovery

He had his son to thank,
but also a crew of Welsh miners

who had come through the valley
a hundred years ago

And they'd come through
this area

looking for limestone
to build Johannesburg,

and they would blast
these caves apart

looking for that rich, white,
pure limestone,

and they'd burn it
and make cement out of it

In the 1880s Johannesburg
was a gold rush town,

little more than a collection
of shacks

But it sat on some
of the richest gold seams

ever discovered

As the gold kept coming,
so did the gold prospectors

The town grew

and construction crews
were desperate for limestone,

essential for cement
and gold processing

Lime miners combed
the high veld outside the town

looking for seams of limestone

Although they likely
didn't know it,

these seams concealed remnants
of ancient cave systems

and were full of fossils

When they found
the limestone seam at Malapa,

they laid their charges as usual

They came in here
and put in three,

at the most four, blasts

One right below me here,
one over on the side,

one over there that I can see

Then, for some reason,

the miners never collected
the blocks of lime

and left the blast hole
largely untouched

I'm not sure why they did that,

but what they did do
in that process

was expose just the edge
of these remarkable skeletons

They damaged it just enough
so we could find this site

and could make these
fossil discoveries,

but not too much that
they destroyed the evidence

It really is a miracle

It was in one of the rocks
scattered by the blast

that Matthew found
the collarbone of a child

But that was just the beginning

The hole where the miners
planted the dynamite

would soon yield so much more

It was only once
I had the permit

and we came back on September 4,
a whole bunch of us

that we spent all morning
looking here

and we found nothing

We were even thinking of leaving

because we thought
there wasn't anything here

I stood over on the other side
of this pit,

looking down into that pit,

and I saw something sticking out
of the rock right down here

And what I saw stunned me

And I climbed down the pit
and looked right over here,

and there
sticking out of the wall

was the proximal humerus
of a hominin

I couldn't believe it...
I did my PhD on this

I climbed closer,
and as I got closer,

I realized there was a scapula
of the shoulder blade in place,

and I came even closer

and put my hand on the wall,
right here,

and two hominid teeth
fell into my hand

Then I said something,

and that started the second part
of this remarkable story

Everyone piled down in here,

at my feet was a proximal femur
in a block here

that clearly belonged
to the child

What was amazing was
it never crossed my mind

that this wasn't the child
that Matthew had found

How could you find two skeletons
in a site like this?

What it would turn out to be,
of course,

was a second skeleton,
the female skeleton

The child would be laying
right here,

just lying in position here,

and it would turn out that
there were other skeletons here

There's one sitting over there

There's a baby
just above me here,

and who knows how many
are in front of me here

It really is a treasure trove
of paleoanthropology

One by one,
they took out blocks of stone

they thought might have
hominin fossils in them,

remnants of our ancient
human family

The blocks were all taken back

to the University
of the Witwatersrand

At the medical school,

Lee's wife, Jackie,
a radiologist,

ran the blocks
through a CT scanner,

allowing the scientists
to peer inside

There you go, okay, that's good

What one of those blocks
revealed was stunning

A slice came through,

and you could see
an entire skull

I was dumbfounded

I could not in my wildest dreams
believe an entire skull

could be sitting
in this little rock

Then began the painstaking job

of freeing the skull
from the rock

that had encased it
for possibly millions of years

It took me three months
to get it out

I was the first one
that saw this

And you can't describe it
to anybody

It's beautiful

I mean, it's been in the ground

for 1 9 million years,

and you're the first person
to see that

I thought,
"Well, you're beautiful"

I basically brought this boy
back to life

Finally, the skull was free

Its small brain
and forward-projecting face

made it clear that
it was an Australopith

But details of the teeth
and other parts of the skeleton

made it unlike any found before

Many types of Australopithecus
once walked the earth

between about two
and four million years ago

Lucy is known as afarensis.

There's also
Australopithecus africanus.

This appeared to be
an entirely new species

Lee called it
Australopithecus sediba

after the waterhole
near which it was found

In the local language Sotho,
"sediba" means "wellspring"

The team was able
to radioactively date

the limestone layers in the cave
with great precision

The layer containing
the sediba skeletons

was 1 97 million years old

That makes these creatures
among the last of their kind,

living right at the end
of the fossil gap

between Australopiths
and Homo erectus.

Here at last was a creature

that could tell us something
about that transition

And the bones
were not just fragments

Here were two remarkably
complete skeletons,

a female and a child

Still encased
in the rock at Malapa

are fragments
of at least three more,

waiting to be excavated

This made sediba the most
complete evidence ever found

for what was going on
at the dawn of humanity

The Australopithecus sediba
fossils

are some of the most
spectacular skeletons known

for early hominids

They're absolutely amazing

We don't get two bones

associated with one another
very often,

much less several bones,
much less partial skeletons

So that makes these fossils
really special

Sediba was exciting
from the get-go

Right away, we knew that
we had parts of the skeleton

and we had parts of the cranium,

which helps us figure out
who this animal is

So that was really,
really exciting,

and initially, these upper limb
bones looked very primitive,

so we knew we were dealing
with something

that looked like it would be
a good climber,

kind of an ape-like creature

Peter Schmid's job is to
reconstruct sediba's skeleton

Unlike past fossil finds,

here, the skeletons
are so complete,

there doesn't have to be
much guesswork

By scanning and mirror imaging,

Peter can fill in any missing
bones with great accuracy

From the CT, we've got
a few thousand slices now,

and Aurore has to put everything
together to form a 3D model

And then we have to cut
the model

because the pelvis
we already casted,

so we only need the rib cage

But the right rib cage
we have already,

but we need now
the mirror image of that,

and the computer helps us to do
the mirror image in a second

Layer by layer,

a 3D printer then slowly prints
the rib cage in fine plaster

Beautiful

Finally, Peter has assembled
a complete skeleton

It's highly unusual

All Australopiths are a mix
of ape and human,

but sediba has a unique
mosaic of features

scientists have never seen
before in the same creature

The arm is very long,
like in a chimpanzee,

but the hand
is with short fingers

and a very long thumb,
like a human hand

which was never found until now

because this is the most
complete hand ever found

in this period

Job Kibii,
who was with Lee and Matthew

when they discovered
the skeletons,

has been working
on the sediba hand

He's found
an unusual combination

of ape and human features
here too

What's special
about sediba's arm and hand

is that we know sediba
has a very long thumb,

which is more chimp-like,

but sediba has
a very human-like hand

For example, sediba has a thumb

which is longer
relative to the other fingers,

which indicates
a human-like condition

Sediba's hand, with its
opposable thumb

and forefingers,

is so human that
it could've been a tool user

But since no tools were found,

that remains only
an intriguing possibility

From the reconstructed skeleton,
paleoartist Viktor Deak

can start to create
a lifelike digital painting

By virtually applying
tissue thickness markers

carefully calculated

from the known facial tissues
of living primates,

he can build up a realistic
impression of sediba's face

Once that was all done,

I have now gone ahead
and created a body for it,

and if you want to see,

we can check all that
by going transparent

and seeing, making sure that
the bones and everything line up

in the proper spaces

So here we have
a concept reconstruction

of how sediba
potentially could look like

The step from there
to a lifelike digital painting

is a short one

Finally, for the first time
in almost two million years,

the face
of Australopithecus sediba

looks out on the world
once again

But the true revelations will
come from the bones themselves

Because they are
so well preserved,

these fossils
will give scientists

unprecedented insights

into the lives
of these ancient creatures...

Everything from what they ate
to how they died

Such details might help explain
the Australopiths' transition

into our genus: Homo

They might also prove
or disprove

a highly influential theory
about the dawn of humanity

A theory inspired
by the very first discovery

of an Australopith fossil

The year is 1924

Anatomist Raymond Dart

teaches at the University of the
Witswatersrand in Johannesburg

His hobby is fossil hunting,

but he never imagines
he will find a human ancestor

Nobody at the time believes
we had evolved in Africa

Well, in the late 19th century,

fossils were found in Europe
with the Neanderthals

They were found in Asia

with the earliest known examples
of Homo erectus.

No one really had a sense

that anything interesting
occurred in Africa

Darwin and Huxley
predicted that our origins

would be in Africa
based on comparative anatomy

You know, they looked
at the skeletons

of chimps and gorillas,

and they looked at ours
and they went,

"Well, they're so close to us

"and they're more close
than anything else,

so it must have been in Africa"

And then the sort of
second generation

of evolutionary biologists
shied away from that

They started to find fossils
in Europe

They started to find fossils
in Asia

And, of course,
that tied in very nicely

with sort of racist,
imperialistic thoughts

of the day

They couldn't abide the thought
of it being in Africa

In late 1924, Raymond Dart
receives a package

He sees it's
from the mining town of Taung

in South Africa's
Northwest Province

And in that box is a fossil,

and this is a game-changing
fossil

It's been sent to him by miners

who noticed what looks like
the skull of a small ape

encased in the rock

Dart is fascinated

He begins the long,
laborious process

of revealing
the mysterious skull

He can see that
it is the skull of a child,

but like no child
he has ever seen before

It has ape-like characteristics,
but also some very human ones

And so as he cleaned this fossil

and he saw the hole
in the bottom of the skull

where the spinal cord enters
the brain underneath

that he had something like a
two-legged walker on his hands

And this he named
Australopithecus africanus,

and what that means is
"southern human of Africa"

Dart rushed into print
with his find

He claimed it is proof
that we evolved in Africa,

just as Darwin had predicted

He was unprepared for the
firestorm his theory unleashed

The Taung child sparked
an incredible revolution

Up to that point,
everybody said,

"Let's look to Europe
for our ancestors"

It was unthinkable that
anything as important

as the emergence of humans
could have happened in Africa

Raymond Dart was a feisty guy,

and when he was pushed back
by the British intelligentsia,

he became feistier,
more aggressive

in terms of his defending
of his views

Most scientists
disagreed with him

He really was seen
as an outsider,

but it absolutely
set the ball rolling

for, one, paleoanthropology
as a field in Africa,

and, two, vindication
of what Darwin and Huxley

had predicted
with actual fossil evidence

It showed once and for all
that our origins were in Africa

and only in Africa,
and that's huge

It totally changed the field

Dart was sure he had discovered
the missing link

between apes and humans

But it wasn't enough
to know what they looked like

He wanted to know
how they behaved

What sort of creatures
were they?

He understood that these great
questions about our ancestors

were also questions
about ourselves

The reason we are interested
in our own ancestry, I think,

is the reason that
you or I want to know

who our parents were
and who our grandparents were

or great-grandparents were,
because somewhere in us,

we realize that there's
a little bit of them in us,

so to understand
the quirks of our own behavior

and why we do things,

if not just why we look
the way we do,

comes from that ancestry

Paleoanthropology is just that
in deep time

We're looking way back

And so we're looking
at the things,

the sort of little bits
and pieces

that drive why humanity
is like it is today

Raymond Dart
was building a theory

about how the Australopiths,
our ape-like ancestors,

became human

His ideas about the dawn
of humanity were the touchstone

for thinking about our origins
for generations

In the 1940s,

more examples
of Australopithecus

began to be found

And a key site not only had
fragments of Australopithecus,

but also the bones
of many other fossil animals

And Dart noted that these bones
were broken in a special way

Dart became convinced
they were weapons

made by our primitive ancestors

Was this the key
to what first made us human?

Dart had been a young medic
in World War I

He had seen firsthand

the barbarity
humans are capable of

It made sense to him
that the origins of humanity

were steeped in blood

Raymond Dart's experience
in the World War

may have colored
his interpretation

of what these bones
and teeth meant

You know, it gave him a view

of the dark side of humanity
and the violence of humanity,

and he came up with this idea
that Australopithecus

had figured out that bones
and teeth were hard

and could be used as weapons
to kill other animals,

the sort of killer ape theory
of early humans

Dart believed that
the more aggressive

and adventurous
of our ape-like ancestors

abandoned their forest
environments

and moved into savannahs

There, they became hunters
and predators

His theory that
this violent transformation

gave rise to humanity
soon found an audience

far beyond the small world
of paleoanthropology

In the 1950s,
there was a drama critic

and playwright
named Robert Ardrey

who became very interested
in human origins,

and he went to Africa
and spoke with Raymond Dart

And Robert Ardrey,
being a dramatist,

could write like anything,
and he wrote this amazing book

published in 1961
called African Genesis.

African Genesis
became a pop science

publishing sensation
of the early 1960s

Ardrey's ideas, building
on those of Raymond Dart,

helped frame public debate
about the dawn of humanity

for the next 20 years

The very first sentence
in that book,

I remember it
because I read it as a teenager

and was enthralled by it:

"Not in innocence and not
in Asia was mankind born"

And in that one sentence,

he encapsulated
Raymond Dart's ideas

that it was an African genesis,
and that where we came from

was not
from an innocent creature

but from the most violent
of killer apes

One of Robert Ardrey's
greatest fans

was the filmmaker
Stanley Kubrick

At the time,
he was planning a film

based on the science fiction
novel 2001: A Space Odyssey.

It was to be a meditation
on human technology run wild

On a mission to Jupiter,

the spacecraft's computer turns
on the crew

At the beginning of the film,

our ancestors discover
the first technology:

weapons

Eventually, they will use them
on each other

This was the "dawn of humanity"
imagined by Dart and Ardrey

And so this sets up then
for Kubrick

the same conflict that Dart felt

For Dart, that first weapon

explained the emergence
of human beings,

while at the same time,

it explained the atrocities
of the 20th century

Are we killer apes at heart?

Is this what we will discover
about our ancestors

at the dawn of humanity?

The discoveries at Malapa
may finally provide evidence

to support or refute
Raymond Dart's theory

The sediba skeletons
are so well preserved,

they give the scientists a
unique glimpse into their lives

And that's the story
we're really after:

how did these individuals
really live

out there in the environment?

What did they do
on a daily basis?

Whether they were so-called
"killer apes" or not

can be seen in what they ate

The first direct evidence
comes from their teeth

At the Max Planck Institute
in Leipzig,

Amanda Henry is analyzing
calculus, or tartar,

fossilized
along with sediba's teeth

Calculus is what happens
when the bacteria in your mouth

form a film on your teeth

So it's this very thick,
layered,

heavily mineralized material
that forms around your gum line

and on all sorts of surfaces
of your teeth

And as it forms,
it traps bacteria and proteins

and remnants of your food inside

Just like the tartar dentists
remove from our teeth,

the calculus from sediba's teeth

provides a snapshot
of what they were eating

So once I have the calculus here
in this little powdered form,

I'm going to dissolve it
in a little bit of a weak acid,

and then we're gonna rinse
that acid off,

and hopefully
what we'll be left with

is micro-remains with
this mineral matrix removed,

and then we'll look at that
under a microscope

and see if we can identify
what was in the calculus

Amanda can see
what sediba was eating

when she discovers phytoliths,

the microscopic
remains of plants

Well, this is a phytolith
that we recovered

from the calculus
of the sediba individuals,

and we have a couple
of examples here

all from different plants
that this individual ate

Here at last is evidence

that will help support
or disprove Dart's theory

Well, this is the first time
that we've had direct evidence

of the kinds of foods
that any Australopith ate

We've had proxy information
before,

we've had sort of
vague categories

where the food's harder
or tougher,

but this is direct evidence

That's exciting

What Amanda can see
trapped in sediba's tartar

are microscopic remains
of many different plants

We have phytoliths from grasses,

we have phytoliths from the bark
or woody tissue of plants,

and we have phytoliths
possibly from fruits,

so all the evidence
suggests that

the foods that this individual
was eating

was coming from closed
forested regions,

so eating fruits,
maybe chewing on stems,

eating the grasses
that are growing in that area

The tooth evidence from sediba

indicates a diet very similar
to today's chimpanzees

While they may have eaten
some meat,

there's little to back up
Raymond Dart's theory

that they were killer apes

So later scientists came
and looked at the evidence

and found that
there were tooth marks

in the skull of
an Australopithecus individual,

and that was just really
compelling evidence

that Australopithecus maybe,
instead of being the predator,

was the prey

So our ancestors, or the early
hominin in South Africa,

were the victims,
rather than being the carnivores

that Raymond Dart
wanted them to be

The caves
in which he was finding

not only the remains
of human ancestors,

but the remains of many,
many, many other animals,

which he thought
were being consumed

and devoured by our ancestors,

were actually all the victims
of predators and carnivores

who were pulling all of those
animals into the cave

It seems Raymond Dart's vision
of our ancestors

as the first killer apes,

so famously portrayed
by Stanley Kubrick, was wrong

The sediba skeletons
are so well preserved,

they offer the team
a chance to investigate

not just the lives,

but the deaths
of these individuals

They can analyze the
two-million-year-old death scene

almost as if it were
a forensic case

I mean, we're looking
at the preservation

of organic material here

These animals are articulated
the way they died

The breakage patterns
may often be a result

of the moments before
or shortly after their death

So far, the team has excavated
the skeletons

of a female adult and a child

So the female was this one

And the juvenile
is all the bones in blue,

all of these

They were found very close
to each other

Aurore Val has been creating
a virtual reconstruction

of the scene
at the bottom of the cave

Besides the sediba skeletons,

there are the skeletons
of many other animals too

How did they all get there?

Two million years ago,
Malapa was a much deeper cave

Landscape erosion has reduced it

to a small depression
in the ground

But when Australopithecus sediba
was around,

it was a cave system
about 90 feet deep

Imagine a vertical shaft
going up

There's probably water dripping
down, roots hanging down

Right here is the curled-up body
of the female,

lying right there
is a child's body,

the 13-year-old boy

There are other animals,
all being eaten by bugs

and going through
the usual process of decay

This reconstruction shows
the sediba death scene

in great detail

Now the team want to know
how all these creatures died

Were they dragged in
by predators, or did they fall?

The man to answer that question
is Patrick Randolph-Quinney

He's an eminent
forensic anthropologist

more accustomed to working
on murder cases and mass graves

I'm involved
in looking at homicides

and involved in looking

at the forensic
identification process,

So, unknown remains,

giving them back their identity
and their name,

that's what I do for a living

The skull of the child
is the first piece of evidence

This is this fracture here,

and it's a fracture
that's actually separated

part of the body of the jaw,

and it runs up through the tooth

And basically,
if you're in an impact,

you jar your teeth together

and you create compression
on the tooth row,

and that provides force,
or generates force,

which goes down
to the tooth roots

And what this has done

is actually split
part of the corpus apart

So it's actually damage

consistent with effectively
an impact on the jaw,

and the energy has come
from the teeth

out into the bone around it

And that only happens
mechanically with fresh bone,

so this individual
was still functioning skeletally

when this happened

The mandible fracture
is a green fracture

that happened when the bone
was fresh, at or around death

It would be consistent
with a fatal fall

The fractures to the forearms
are even more telling

And if you look at MH2,

she's got a fracture that runs
through the body of this joint,

where it articulates
in the elbow with the humerus,

the bone of the upper arm

There are also other fractures
associated with the wrist,

in this portion of the ulna
and this portion of the radius

And we've actually got fractures

in the scaphoid and triquetral
bone in the wrist as well

And what this appears
to indicate

is putting your hand out
to stop yourself

This seems to be good evidence

the individual was alive
when she fell

The cave at Malapa
was probably a death trap

Were they searching for water
and lost their grip?

Perhaps they were trying
to escape in terror

from some predator

Whatever the reason,
they fell and died

either immediately on impact
or soon after

It appears that mud
then buried the bodies,

and as it hardened,
kept them from disintegrating

This is why they were
so well preserved

Then began the long,
slow process of fossilization

in which all organic material
in the bone

was replaced by minerals

Today, the sediba fossils
are still yielding insights

into the Australopith world
of almost two million years ago

But the most tantalizing
question of all

is still unanswered

How did these primitive
creatures evolve

into more advanced
human ancestors?

To find out,
scientists need to find

perhaps the most elusive
fossils of all:

the first members
of our genus Homo

For decades, the only fossils
that came close

were the fragmentary remains of
a creature called Homo habilis:

handyman

In the early 1960s,
fossils discovered

from Olduvai Gorge in Tanzania
by the Leakeys

led to the definition
of a new fossil species

in our evolutionary tree:
Homo habilis...handyman

And what was significant
about that

is that stone tools
were connected

with what Leakey proposed
as the first human,

a member of our lineage,
the genus Homo

Like most scientists
at the time,

Louis Leakey thought
our evolution

was probably a gradual,
linear process:

a single chain of species

becoming progressively
more human

He decided the key event

that made our ancestors cross
the threshold to humanity

was not the invention
of weapons,

as Raymond Dart believed,
but tools

Since Homo habilis seemed to be
the first toolmaker,

he declared it the first member
of our genus: Homo

Here at last was the link

between the ape-world
of the Australopiths

and the human world
of Homo erectus.

So there was always this gap
between Australopithecus

and later members
of the genus Homo,

like Homo erectus
and Neanderthals,

and we didn't really know

what species in that gap
would have looked like,

and then along in the 1960s,
along comes along Homo habilis,

and it's slightly
bigger brained,

it's probably
a bit more bipedal,

and of course it had these stone
tools associated with it,

and it was argued very strongly
to be a contender

for early Homo, and it was
instantly controversial

and it's still controversial
to some people today

It's a bit of a mess

Because it became clear
probably in the 1990s

and moving
into the early 21st century

that Homo habilis, we really
didn't know what that was

One of the main reasons
for classifying it as human

was that it was found with tools

But that is now looking less
like a defining characteristic

of the genus Homo

We now know that even the more
primitive Australopiths

had the capacity to use
stone tools

Zeresenay Alemseged,
who discovered

a three-million-year-old
Australopith

called Dikika child, has found
what he believes to be evidence

of stone tool use
in the same period

If you were defining
Homo habilis as a toolmaker,

tool user,
then what do you make of it

when you see
that Australopithecus

was doing the same thing?

We know that there is
rudimentary stone tool use...

Not stone tool but stone use...
Among living chimpanzees

The confusion surrounding
Homo habilis has grown

It has been compounded

by the fact that so little
of it has ever been found

Colleagues have said, you know,
if you had a shoebox,

you could put all those fossils
that might be early members

of the genus Homo into it

and still have room
for a good pair of shoes

With so few fossils to go on,

scientists had little
they could say for sure

about the first members
of our genus, Homo

This was the situation

when the two young cavers,
Rick Hunter and Steven Tucker,

made their discoveries
in the Rising Star cave

When Lee saw the photos
from the fossil chamber,

he could only hope they would
clear up the confusion

Was it another sediba
or was it even Homo habilis?

The only way to find out
was to bring up the fossils

Lee knew there was
no time to waste

I had to make a decision,

and about, oh,
just before 1:00 a m,

I decided that history
would never forgive me

if I did not act right then

Just five weeks later,

the Rising Star excavation
was beginning to take shape

Its planning had taken
some ingenuity

Lee knew he would never be able

to get down to the fossil
chamber himself

In places, the chamber entrance

was less than seven inches wide

I put a call out
on Facebook saying,

"I need skinny scientists

"who are not claustrophobic,
who are cooperative,

"who can work together

"in a dangerous
and difficult environment

And I need you available
by the first of November"

I saw Lee's Facebook post,
actually,

and on a whim I applied for it,
and then the next thing I know

I got asked to interview
and from there,

just things started happening
really quickly

I saw a call that came out
on Facebook from Lee

that was looking
for skinny scientists,

skinny paleoanthropologists,

that weren't claustrophobic
and that would be able to fit

into a slot that was
about 18 centimeters,

and that was very intriguing

I didn't say what
had been discovered

I didn't say anything
about what I thought it was

They only knew it was me
in South Africa

and it was clearly underground

I thought I'd get three, four,
five applicants, I really did

I mean, how many people
in the world could be qualified

and fit that criteria?

Within ten days I had
57 qualified applicants

from all over the world,
most of them women

One morning I woke up
and there was a call

for tiny, experienced
archaeologists from Lee Berger

and I thought, "That's me"

I received the Facebook post

via a friend who saw that it was
an ad for a small archaeologist

with caving
and climbing experience

and she said, "That's you!"

I'm almost finishing a PhD
in physical anthropology,

osteology, so this is my area

I'm an archaeologist,

so I can study up quick
on the paleo stuff

I'm a Ph D candidate

specializing in evolutionary
biomechanics,

so more on the paleo-
anthropological side of things

It really seemed perfect,
in fact

When I read the callout
to my husband, he said,

"Well, they might as well have
just meant, you know,

written: 'Marina is wanted
over here ""

So

The Rising Star expedition

was to be a new kind
of paleoanthropology

tailor-made for the age of
social media and the Internet

I held Skype interviews, and
I did a few things in that,

with the 11 people
I'd short-listed

out of this spectacular list
of applicants

Lee explained a little bit
about how the cave was found

and shared with us
some video footage

and the initial photographs
that Steve and Rick took

And he told us about
the conditions of traveling

into the cave

So, you know, he wanted to make
sure that we really knew

what we were getting into

It was mysterious

It was very enticing
for that reason

You know, sort of wondering what
sort of circumstances there were

that necessitated asking
for small people

with excellent
paleontological skills

In the Skype interviews,

I wanted to see these people
face-to-face,

but I also wanted to test
some things

I needed to know that
if I shut the cameras off,

which I did for many of them,

I want to hear
if they could respond to me

Because I had already
designed by then

this system of communication,
I knew

I knew I was never going to

I will never set foot
in that chamber

Then maybe a day after that,
I was told I was a go

It was so fast, so fast

And I sent off emails saying,

"Congratulations, pack your bags

Expect to be here
in the first week of November"

Then I got the email
that said that I got it

and then characteristically
I bust out crying,

and just kept reloading
my email to make sure,

refreshing it, just like,
really, it's really there,

it's really there,
and I screamed so loud

It was a very quick process

The ad went up

and then the interviews
happened the next week,

and then I learned a day later

that I was accepted
to the project

All of a sudden I was
rearranging my schedule

and waiting for the plane
tickets and packing up

and reading quickly everything
that I needed to know and

so it was fast and furious
getting ready for this

My brain was just like a flurry,

like an explosion of glitter
and confetti

Just

It's everything, it's like every
best birthday and Christmas

and Hanukah and Kwanzaa and
it's everything, all at once

I figured if he thought
I could do it,

if Lee thought I could do it,
then I could do it

I had no illusions that
this was going to be easy

Nothing like this
had ever been done,

certainly in the African context
I knew, perhaps ever,

anywhere, and I knew
I had to have everything

from medical support
to safety support to the design

of the infrastructure
underground and above ground

and all the things that go on
with a scientific expedition

Yeah, let's get a bag

As the camp was set up, Pedro,
Rick and Steve readied the cave

for the excavators

Safety lines, lights, cables
and cameras were installed

The possibility for accidents
was ever present

Lee rehearsed safety procedures
over and over again

Critical issue is, no one panic

Yeah, yes, we see you

A command post was set up
from which he could watch

virtually every part of the cave

I really began to get a feel

for what I was putting
these young women into

as the cavers who were laying
over two kilometers of cable

And I think they were terrified
and I was terrified,

They were still untested

We took them through the caves
testing their capabilities

in this system

And so we reached the 10th,

which was my intended day
of going in

and we tested systems,
everything worked

It was a little sloppy
but it worked

We tested safety, it all worked,

and by the early afternoon
we were ready

You'd be surprised, I'm actually
a person of gentle soul

Is it weeping in the corner
like a Gollum?

Marina, Becca, and Hannah have
been chosen to go down first

Still, nobody knows
exactly what they will find

I've seen a skull,
I've seen the other pieces

I am pretty sure that we have
got quite a lot of a skeleton

of at least one hominin

That of course waits to be seen,

and it's going to happen
pretty fast now

over the next several hours

Anxiously watched by Lee and
the team in the command post,

Marina, Becca and Hannah
make their way

deeper and deeper underground

The descent is difficult

And as I looked down there
I thought, oh, you know,

I don't know if I'm
if I can do this,

but then once I was committed
to go down, it was actually

much, much easier
than I was dreading

just trying
to also slow it down a bit

because I've got
the GoPro running

It was just an amazing,
an amazing feeling to realize

how far away you are
from everyone up top

in the command center,
and to just fully realize

what you are down there to do

I became a little bit
overwhelmed,

but you also have to turn
that off in some sense

because you're only down there
for a limited amount of time

and you have a job to do,
a very important job to do

Going down the chute
for the first time was

honestly it wasn't as bad as I
thought it was going to be

And then you come
into a landing zone

and there's a hallway
to pass through

It's not really a squeeze,

but it's a narrow passage
to pass through

and then the chamber
opens up again

This is the entrance
to the cave here

So you start by descending down,
you know,

a fairly narrow shaft
and some tunnels

You get down into an area here

This is what we call
the Superman crawl,

which is a very narrow crawl

You have to crawl on your
stomach for about three meters

Then you enter
into another chamber

This is what we call
the Dragon's Back,

so that's the ridge climb

with the sort of four- or five-
meter drop on either side

You get up to the top
of Dragon's Back and you end up

at the top of the chute,

which is another sort
of tunnel access

that then you start the 12-meter
descent into the chamber,

so that's this area here

Once you drop into the chamber,

you're actually just
in a landing zone

It's another sort of antechamber

You then go through
another passageway

into the main chamber,

which we call UW-101,
or the fossil chamber

Marina is the first
to enter the chamber

There was a little bit of
trepidation, I have to confess,

and a lot of excitement

to be the first of the advance
scientists to go into the cave

The first thing that came
through my mind

when I went through
the final slot

into the actual final chamber
was Howard Carter's anecdote

about opening Tutankhamen's tomb

I think it was Lord Carnarvon
in the back saying, you know,

"What do you see?"

And Carter says,
"Things, wonderful things"

And it was that feeling

God, this place is beautiful

First of all,
the cave is beautiful,

just geologically beautiful,
and then you look down

and it was just a sea of bone

and it was obviously
just not regular bone

So, yeah, it was amazing,
amazing

And then I saw them enter
this chamber

We got the cameras set up and
you could see their feet moving

And it was surreal

Fantas

Fantastic!

There we go

Skull is being flagged

You can see the skull here

She's now flagging the mandible

And then the process started

The process
of doing science began

So we'll put pin #1
right beside the mandible

and that's where
we'll concentrate

Okay

Okay, das ist super.

Okay, thanks

Bye

Yeah, that's perfect right there

Okay, going to start scanning

Okay, scan

The first foray into the fossil
chamber lasts only a few hours,

enough time to start scanning
and flagging bone fragments

as well as to test
the safety systems

Okay, how did that go?

Let's see

It's mapping right now

Finally it's time to bring up
the first precious fossil,

the mandible

Uh, there, there, coming

I see what looks like a mandible
in the middle there

On the right

That looks fantastic

It's Becca who will take care
of it on the ascent

All right!

You got the fossil, huh?

Yes, I got the fossil

Well done

Here you go

And we have everyone else

Everyone's out Rick's out safe

They're all out Well done

And so first their safety,
in that they were out

was just this enormous
emotive relief,

and then the sense that they had
actually got this thing,

so now I was going to see
for the first time

what all of this was about

When they opened that little box
and we unwrapped this thing

that they collected,

every great idea we had

went out the window,
gone, you know

Suddenly we didn't know
what we had

When he had first seen
the jawbone

in Rick and Steve's photos,

Lee had decided it probably
belonged to an Australopith

One of the most striking
characteristics

of an Australopith's face is its
large, apelike jaws and teeth

As the Australopiths
transitioned

into the genus Homo,
their faces shrunk

Jaws and teeth became smaller

When he finally had
the jawbone in his hands,

Lee saw it was too small
to be an Australopith

It seemed quite human

Could it be a new specimen
of Homo habilis?

Or could it be a new
transitional species

between Australopiths
and early Homo?

These are the questions on
anatomist Peter Schmidt's mind

as he studies the mandible
from Rising Star

You have this molar teeth

and the very strange use
of the frontal part here

And luckily we got another piece

so with these two pieces
we have a hemi mandible

which is complete and then we
can put on the mirror image,

and we have sort of outline

Peter can then compare it
to the mandible of Homo habilis.

I will take this away

and you see this is the tooth
row of Homo habilis.

You see also that these are
massive teeth, but the tooth row

is straight and we have
a very strong shelf here

The mandible from Rising Star
is clearly more curved

It's not Homo habilis,
and it's not an Australopith

They don't know what it is

This is pure confusion

We don't know what to make of it

We realize all of our
preconceived notions

have to be tossed aside

We can't go into this thinking
it's going to belong

in this group
or belong in that group

We just have to start
from literally scratch

The team hopes that as more
fossils emerge from the cave,

the confusion will clear up

It's so solid

There is reason to be optimistic

Each descent reveals more bones

Where once they thought there
might be one individual,

they now see evidence
of a whole lot more

It was probably a couple
of hours into the first day

when we realized
it also wasn't one skeleton

Another femur

If I remember, right,

it started with a second femur
from the same side

and since there has never been
a three-legged hominin,

we knew there were two,
and then there were three

And I think it was by day two,
there were four

And we realized we were

in something
very, very, very special

All right, good luck with that,
Becca, we can't wait to see you

You've got something
we want to see

Every time the scientists in the
cave remove a piece of bone,

they find more bones beneath it

It's everywhere

I mean, it's all strewn,
all throughout

Not just the chamber, but
the passages leading to it

are littered with bone fragments

At the landing zone
where they stopped,

I'd get a call on the intercom

"We found another tooth"

It was just sitting there

I was trying to find a nice
place to sit, and there it is

It just caught my eye

Rick was sitting there
as a safety caver waiting,

and he kicked the dirt
and hominins fell out

You have to pass me up
some flags

Do you have enough flags?

By the afternoon of day 14
in the expedition,

we were overwhelmed

I'd started with one safe
to hold one skeleton,

day three we had two safes,
day four we had three safes,

day six, people were going,
"We need more safes"

Woo-hoo!

Tooth und more

I don't know whether
you should hug me

for someone finding something
in the other spot

Oh, man

By day 14, as we would get
fossil after fossil,

we were getting 40, 50, 60,
70 elements a day,

all that was flashing through
my mind as I was doing that

was that famous scene in Jaws
where Roy Scheider is chumming

and they hadn't yet
seen the shark

And he's sitting there chumming

and all of a sudden
this gigantic shark appears

And he goes, "We're going
to need a bigger boat"

We're gonna need a bigger safe

It's extraordinary

I think this year at Christmas
I'm just going to hang

one of these
instead of a stocking

As the fossils accumulate
in ever-greater numbers,

a picture of the creature
of the Rising Star cave

begins to emerge

This is part
of a juvenile pelvis

Thigh and hip bones tell them it
was an upright walking biped,

but its gait was primitive

From what they can see of
the exposed skull, it is small,

not much bigger than a chimp's

I'm gonna have to tell
them to leave that alone

But the teeth and jaws seem
more advanced: Homo-like

The team's excitement grows

It's beginning to look as if
they have found another species

from the dawn of humanity

But on which side
of the Australopith-Homo divide

will it fall?

One of the key fossils that will
tell them that is the skull

They are saving that until last

Distance is perfect

And I can see marker two

Record

Recording

In the meantime,

another extraordinary fact
is becoming evident

There are no other animals
in the cave

All the fossils
are human ancestors

This is unheard of

It was pretty surprising

that something completely normal
to every other excavation

I have ever been in
on the continent of Africa,

everyone I have ever heard of
on the continent of Africa,

wasn't happening here

We weren't getting anything else
other than hominins

When early hominins are
discovered in caves,

they are always found along
with the bones of other animals

that have either
wandered in and died

or been dragged there
by predators

They're mixed with antelopes
generally in huge abundance

Then you get, depending
on the circumstance,

some carnivores and other bits
and pieces, and rodents,

and the stuff that accumulates
when things die

and are eaten
and are dragged into caves

Apart from the bones
of a solitary owl,

there's not
a single other animal

in the Rising Star chamber,
only hominins

So how did these creatures
get in there?

The chamber is
very inaccessible,

deep in the dark zone of
the cave, with no entrance

other than the long,
narrow chute

The team believes it likely
was just as inaccessible

two million years ago

It is starting to look

as if the bodies might have been
intentionally placed there

Could this possibly be
some sort of burial?

There has never been evidence
of anything like this

linked to such
a primitive-looking ancestor

So we got that looming
in front of us

and don't have an answer to it

Until now, the earliest
known burials

are from about 100,000 years ago

and a much more advanced form
of early human

The team doesn't have a date yet

for the fossils of Rising Star,
but it seems unthinkable

that such a primitive-looking
creature

could be disposing of its dead

But that's what it looks like

And the age ranges of the
individuals are very similar

to what archaeologists find
in cemeteries

At the early stages
of this expedition,

they look like
a cemetery population:

very young individuals
and very old individuals

and nothing in the middle so far

It doesn't mean we're not going
to find it,

but that's what you see in a
cemetery when you dig it up

Right now it looks
a lot like that

Will it hold out to be that?

That will be a mystery
I want to see solved

And we're left with
this conundrum of, you know,

is what we are looking at

You almost don't want
to say it out loud

It's a mystery with
profound implications,

but one that will require
further analysis

before anyone is willing
to back it wholeheartedly

The excavation
is now approaching

its third and final week

Perhaps the most important bone

has been left until
near the end: the skull

Its shape and the size of its
brow ridges will be crucial

in telling them whether
the creature of Rising Star

is Australopith or Homo: human

We're going to go ahead
and bite the bullet

and take that skull out, okay?

Yes, yes, yes, yes, good, good

If only because it
gets it out of the way

Yes, I know

Not because you want it out
to see it, right?

Oh, I want it out!

A couple of reasons
we want to get it out

One, the skull
can tell you a lot

It can tell you
cranial capacity,

start getting an idea
of the shape of the skull

Is it Australopith-like
and pinched in the front,

or is it rounded
more like a human,

or is it something in between,

does it have
a sagittal crest neck?

We want to see that skull

And also the skull was probably

the most complex
initial extraction

It is fragile,
it's a thin piece of bone,

and it could break apart

We need to know whether we could
get something like that out

And we need to get it out to see
what was underneath it,

whether this was a skeleton

or whether there were
lots of individuals

associated with each other

So there was all this tension,

and it was a lot harder
to extract than we thought

Oh, I'm sure you'll find plenty

All right, stage on in after her

Good luck, everyone

Have a blast, huh?

Thank you Will do All right

Let's get you something here

Go get 'em!

Good luck

Happy hunting Thank you

Enjoy topside

The skull is extremely fragile

The team carefully scans
the area immediately around it

How big?
Yeah, those are perfect

Then they begin the laborious
process of removing

every tiny fragment of bone
surrounding the skull

Oh, we've got medium bags now

Finally, they delicately scrape
away the dirt to release it

We're done this easily

Got it

Everyone was feeling
all these points of tension

around the science of the skull,

when we knew it was imminent
coming out

We only had two people
down on the bottom,

and they were working on it,
Becca and Marina,

and working and working
and working, and finally

we kept trying to call them out
and they wouldn't come out,

because they knew they were
that close to the extraction,

and eventually it did come out

That's it

That's it

It's so fragile

With everyone holding
their breath,

praying that it doesn't break,
the skull fragment is finally

lifted and delicately placed
in a box

That's it

Then it begins its slow ascent,
leaving the cave

for the first time
in possibly millions of years

He's holding the box

Yeah, that's right,
he's holding the box,

so he can't do this, he's gotta
be much more careful than that

Yeah, all right,
there it is, all right

How fantastic

Wow

And all of those scientists
piled back in, all of the people

that spent so much time
and so much energy

coming to this moment,
went back in there,

and they lined up
in the most difficult places

up the Dragon Back to Base 1
and they knew there was a risk

that it could get damaged, if
dropped it could get destroyed

And this huge team effort
occurred as they handed this off

from one to the other,
as it moved its way

from this dark recess where it's
been for however long it's been

to the entrance of the cave
where those of us

not privileged enough to be able
to get into this system

had to wait with huge tension,
watching this passage

on the cameras
until there it was

There you go folks,
let's go get it

Great moment

It's like a Rocky moment

There is so much wonder,
no one's bored,

no one's too academic
to hold it in

Everyone is just brimming
with childlike excitement

Would you hate me
if I took this before I hug you?

Please take it

Oh, well done

I don't even want to hug you
with that thing in your hand

I'm going to give this
off to John

I'm constantly sitting there
and stopping myself and going,

"Oh my God, this is like...
It's old

"It's probably the first time
this fossil has seen

the light of the day
in millions of years,"

and so I'm continually sort of
having to stop and just think

for a moment and sort of
revel in it

It's the moment everyone
has been waiting for

They hope the skull fragment
will be the telltale piece

to identify the creature
of Rising Star

as either an Australopith
or a member of our own genus

Looking at a left frontal,
so it's this part, the orbit,

and then part of the brain case
behind the orbit

And that is
a very important piece

Large orbital ridges
with indentations behind them

would indicate Australopith

Smaller brow ridges

with evidence of a more rounded
skull would say Homo

We do have our genus

We do?

We have our genus with that

Yes, yes!

The team's verdict is clear:

they have a new member
of our genus

Did we do good?

We did good

Now the question is:
what can it tell them

about the mysterious
dawn of humanity?

We are certain that this is in
the genus Homo, our genus,

and we are certain
it's a new species

And that's where we are
right now

The idea that we've discovered
a large number of individuals,

males and females,
young and old, of a new species

in the genus Homo

In the next phase,
they'll have to piece together

and analyze the rest
of the fossil remains

Already they have
almost 2,000 bone fragments

from more than 12 individuals

The Rising Star discovery
is one of the most startling

and amazing discoveries
in all of hominin evolution

To have that many fossils
in one place is unprecedented

and took everybody by surprise

The excavation was planned
as a three-week operation

As it nears its end,
the scientists know

they will have barely scratched
the surface of what Rising Star

has to offer

I had never seen or dreamed
of anything

like the richness of this site

There aren't just hundreds
of bones,

there are thousands of bones,
it's clear

You can't blow on the ground

and it doesn't uncover
another one

They can't gently brush their
hand across it, and teeth,

and long bones don't fall out,
usually of another individual

This is going to take
a long, long, long time

As everybody goes home,
the Rising Star fossils are

carefully transported to the
University of the Witwatersrand

It was here, 90 years ago,

that Raymond Dart sparked
a firestorm

by declaring that the dawn of
humanity was in Africa

It seems fitting that it is here
too that the mysterious

early humans of Rising Star
will begin to tell their story

At a symposium six months
after the excavation,

researchers meet
for an intensive analysis

of the fossil material

Yeah, yeah, yeah, yeah

They're in the
analytical phase here,

they're in the diagnostic phase,
and it's been an experiment

in, you know, working together,
bringing together some of

the brightest minds
on the planet with some of

the most current data sets

to analyze over 1,700 fossil
hominin remains

that we recovered
only last November

And it's been fantastic to watch

I mean it's this constant energy
of science

And you can almost feel it
in the room right now

We are total nerds,
it's nerd heaven here,

but I mean it is an
extraordinary experience

There's never been anything
like this before in the field

of hominin paleontology,
to get a group of young,

talented scholars together
to bring their new techniques

and their fresh outlooks
on the record

to newly discovered
fossil hominin remains

This certainly never happened
when I was a Ph D student

and I would have died
to have done this

As the analysis goes on, the
bones from the Rising Star cave

are finally ready
to be presented to the world

We've got a new species of
early human in the genus Homo,

and that's tremendously exciting

We've never had anything
in that transition period

between the late Australopiths
and the earliest members

of our genus in any kind
of abundance,

and boy, we have it
in abundance now

To members of the team,
the fossils suggest a creature

unlike anything ever found
before

We're looking at creatures that
are humanlike in their feet,

humanlike in their hands,
humanlike in their teeth,

everything that interacts
directly with the environment

is Homo

And everything that is sort of
central... you know, the trunk,

the architecture of the
vertebral column, the brain...

Those sorts of things
are more primitive

It's like evolution is crafting
us from the outside in

We've called the species
Homo naledi and "naledi"

means "star" in Sotho
and we've called the chamber

that the fossils come from,
it still has fantastic fossils

to be found,
the Dinaledi chamber,

which means the chamber of stars

Homo naledi is a strange mosaic
of ape and human,

small brained and small bodied
with chimp-like arms,

but with human hands, teeth,
small brows and long legs,

probably a long-distance walker

Naledi is

a surprise in very many ways

It's got an incredibly tiny
brain,

a brain that's more than
a third as small

as a modern human's brain is

Yet it's clear when you look
at the cranial shape,

the dentition, the legs,
particularly the feet

and even the hands, that this
thing is part of our genus

Here are creatures on the cusp
of becoming human,

but still very close
to the Australopith world

It makes the question
of how they got into the cave

even more intriguing

It looks like they got in there
because somebody put them there

Now, if we say that,
you have to understand

that's a very controversial
thing to say

And in so we approach it
very conservatively

We can show that there's
no signs of predation

We can show that there's
no predator that accumulates

only hominins in this way

We can show that they didn't
all get there at once

We can show there's not a flow
of material into the chamber,

and that's where we leave it
scientifically

You know, we can say, the best
hypothesis we can come up is

they were put there

If this is true, its
implications are far-reaching

They now know that
the Rising Star hominin had

a brain size in the range

between 450 and 550 cubic
centimeters

That's just slightly larger
than a chimp's

So if in fact the Rising Star
hominins are purposefully

disposing of their dead,
we're talking about

some small-brained hominins
who are doing this

And that begins to change
our thinking about sort of

the cognitive attributes and the
neural machinery that you need

to engage in that kind
of behavior

And that becomes really
interesting

The accumulation of Homo naledi
skeletons in the cave raises

the type of big question that
Raymond Dart wanted to answer

What type of creatures
were our primitive ancestors?

If the naledi skeletons
have indeed

been intentionally disposed of,
some sort of burial,

it would indicate already
quite advanced social behavior

This fits with new ways
of thinking about the transition

from ape to human

Many scientists now believe that
a key element of that transition

was the growth of ever-stronger
cooperation and social bonds

Psychologist Michael Tomasello
has spent a lifetime

comparing the social behavior
and capacities of chimpanzees

and human children

Well, there's social
and there's ultra-social

And all mammals are social
to some degree

Great apes are especially social
in the sense that they form

long-term relationships
with others

and have bonding relationships
with others, and they groom,

they support each other
in fights

So they're very highly social
creatures, but a lot of it

is organized around competition,
so a lot of it is organized

around coalitions to fight
over food and so forth

And in humans we of course
haven't lost our selfish

and competitive streak,

but we have become so much more
cooperative

Not perfectly cooperative,
but much more cooperative

The fact that we can

sit in an airplane

with 300 or 400 individuals
of breeding age

that we aren't related to
and not rip each other apart

is a uniquely human character
and it was evolved

on this landscape behind me

Because Africa is a harsh place
and we as early humans had

to evolve cooperation
in order to survive here

We didn't have big canines,
and sharp claws

We just had each other

Humans are the most highly
social primates

ever to walk the earth

We bond and form relationships
far more complex

than any other primate

So if the Rising Star chamber
is indeed a burial,

perhaps this would suggest that
here at the dawn of humanity

those more complex social bonds
had begun to take shape

This possibility will generate
fierce debate

as other scientists weigh in

But how do these discoveries
change the narrative

of human evolution?

There is an old refrain
in paleoanthropology

People always say we need more
fossils, we need more fossils,

we need more fossils,
but the fact of the matter is

more fossils just complicate
the picture

One compelling question
to be answered is

where do these new
fossil ancestors fall

on our family tree?

Dating the fossils is proving
to be difficult and complex

It will take time

The thing that's hard about it
is we don't know how old

those fossils are, and we can
tell what they look like

because we have so many of them,
but if they're 3,000 years old

or if they are three million
years old it's going to mean

a very different thing for how
it changes our understanding

of human evolution

Because we have a date,
things are a little clearer

with the Malapa finds

At 1 97 million years old,
most scientists believe sediba

is too late to be a
direct ancestor of ours

Our genus Homo was already
established by the time

sediba came along

But even if sediba
is not our direct ancestor,

it does show there were
many different types

of primitive ancestors living
together at the same time

Okay, yeah, yeah, keep pulling

Great, great!

The quality of the material
that Lee is uncovering

is really phenomenal

Sediba shows that we had
more than two or three species

in South Africa
1 9 million years ago

It's a very interesting find

It shows that there were
diversity

It's a beautiful material,
but I don't think that sediba

was ancestral to our genus Homo

Whether or not they are
our direct ancestors,

the fossils at Malapa
and Rising Star point us toward

a new way of thinking
about human evolution

We have the strong tendency
to want to draw simple lines

between species,
and make nice family trees,

and we have to understand
that that's our need

That's our desire

That's not necessarily
the way that nature works

It's very natural to think about
human evolution as a sort of

family tree in deep time

But evolution is much more
complex than that

Evolution is bushy,
there are different experiments,

populations try different
adaptations,

they try different ways
of being about the world

Paleoanthropologists talk about
the bushiness of human evolution

as a metaphor for the many types
of early hominins

and the difficulty of knowing
which one led to us,

but even that metaphor
may not do justice

to the way evolution works

Nature is messy

Nature is complicated

Nature does not really respect
our desire to put fossils

into neat bins and to sort of
name nice neat species

Both sediba and naledi
have a mosaic of Australopith

and Homo features

They seem to show
that at the dawn of humanity

there were multiple evolutionary
experiments with small-bodied,

small-brained,
upright-walking apes

Scientists now know some
of these varieties

of late Australopith
and early Homo lived together

at the same time

And some of them may have been
interbreeding

These aren't fully formed
species and there's a lot

of interbreeding between
these groups

Some adaptive features
are evolving in one group,

other adaptive features
are evolving in other groups,

and by interbreeding those
are coming together

And if that's the case we may
never be able to draw neat lines

between any of these groups
and later Homo

Perhaps now we need
a new metaphor to help us

understand our evolution,
one that expresses better

the dynamic and fluid nature
of it

Now perhaps the best metaphor
is a braided stream

And that's brought on
by discovery of these

mosaic hominins like naledi,
sediba, and others

They're showing us there's
lots of experiments going on

Some of these evolutionary
experiments died out,

others came together
and interbred

The ebb and flow of genes
through these groups

was probably so complex
that we may have to give up hope

of discovering a simple
linear evolution

So imagine in your mind
a glacier in the top of a valley

and what happens is as it melts,
it creates many, many rivulets

and some of them are large
and some are small,

and they all move off
down the valley

And almost inevitably at the end
of that valley is going to be

a lake, of which some,
maybe the majority,

but not all are contributing to

I think we have to begin looking
at these species we're finding

as almost individual channels
in a braided stream

It's clear they have something
to do with the end-population

and that's us, the billions
of human beings alive today

But it's hard to tell
which one's the most responsible

for us being here

The new finds on the plains
of South Africa are adding

a vital new chapter to the story
of our origins

The tantalizing gap
in the fossil record

at the beginning of our genus
is being slowly filled in

Finally, there is light
at the "Dawn of Humanity"