Original subtitles

Ever since Darwin put forward the idea that we evolved from apes,

scientists have been searching for evidence of the first creatures

that left the ape world and crossed into ours.

The so-called missing link.

But these bones are extremely rare,

allowing only fleeting glimpses

of how we slowly changed from ape to human.

Now, deep inside remote underground chambers in South Africa,

not one but two new species of hominids,

our ancient ancestors, have been discovered.

There it was, right there.

One of the most spectacular early hominids ever discovered,

lying on the surface of the cave.

And not just a few bone fragments...

..there are thousands.

It's everywhere.

Ah, 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, you know, "What do you see?"

And Carter says, "Things, wonderful things."

We have found a most remarkable creature and a most unexpected one.

This is the story of a discovery that could rewrite

the history of our evolution

and transform our understanding of our human origins.

We realised all of our preconceived notions have to be tossed aside.

And this unique find is already throwing up revolutionary

new theories about how our earliest ancestors lived and died.

It looks like they got in there because somebody put him there.

Now, if we say that, you have to understand,

that's a very controversial thing to say.

Were these primitive creatures burying their own dead?

Right now, it looks a lot like that.

Will it hold out to be that?

That will be a mystery I'd want to see solved.

In Autumn 2013, cave enthusiasts

Rick Hunter and Steve Tucker set out

to explore a deep cave system near Johannesburg in South Africa.

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 were planning to document Rising Star's

spectacular crystal stalactites.

But they were about to find more than they bargained for.

I wanted to show Rick a great climb

in the cave called the Dragon's Back.

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 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.

As Steve squeezed into the crevice,

he realised there was a void beneath his feet.

He'd stumbled onto a hidden chamber,

undiscovered by previous explorers.

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 keep on lowering yourselves until your arms are

almost fully stretched out, and then you start to feel a couple of rocks

which you can actually put your feet on.

Curious to explore this unmapped part of the cave system,

Steve and Rick dropped into the hidden chamber.

Above their heads, they saw rare rock formations.

But the real discovery was beneath their feet.

We saw, at first, one bone lying around.

We looked around a bit more and found another bone.

We actually spotted teeth in the rocks and realised

that we actually had found something.

Followed by a skull in the ground.

And, finally, one of the most interesting ones, the mandible.

With four teeth in it.

The cavers had no idea what kind of bones they were looking at.

They decided to take photographs of their find

to a leading expert in the study of human origins.

Lee Berger is a professor of palaeoanthropology

at the University of the Witwatersrand in South Africa.

For 18 years, he'd been searching for the elusive remains

of our apelike ancestors.

But nothing prepared him for what Rick and Steve

were about to show him.

They flipped open a computer,

and I saw...

..something I don't think I ever dreamed

I would see on a computer screen.

That was a mandible...

of what was clearly an early hominid.

The teeth just perfect.

The next picture had a skull in it, of a hominid.

I could see it in outline.

There were bones everywhere. They'd take...

Every one of them, I could see in the image, were hominid.

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.

Lee instantly recognised the bones were from some kind of hominid,

creatures from the human evolutionary line.

These early human fossils are probably the rarest

sought-after objects on earth.

We in palaeoanthropology 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.

The photographs from the chamber at Rising Star suggested Rick and Steve

had stumbled onto a treasure trove.

Could this discovery illuminate one of the great mysteries

about our origins:

Exactly how we evolved from apelike creatures into human beings?

There's a big gap in the fossil record

with only a few little fragments.

The fossil record suggests that in that million year gap,

between two to three million years ago,

lies the birth of the genus, Homo.

It's perhaps the least understood

and most important episode in our evolution.

On one side of the gap is Australopithecus,

an apelike creature with a tiny brain.

They walked upright, but belonged to the world of the apes.

An Australopithecus is sort of like a bipedal ape.

If you went back in time and saw them walking around the savanna,

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

but they would have been smaller in body size. Their brains wouldn't

have been as big so their heads would have looked smaller.

Their jaws and teeth were very large.

Scientists believe that between two and three million years ago,

these Australopiths evolved

into the first recognisably human species,

Homo erectus.

They have big brains and small faces,

adaptations for using tools.

So what went on in the transition from the apelike Australopithecus

to the humanlike Homo erectus?

Lee Berger hoped the new discovery in the chamber at Rising Star

could provide crucial new evidence.

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

I had to make a decision,

and about...oh, just before 1am,

I decided that...

..history would never forgive me if I did not act right then.

Recruiting a team of anthropologists capable of excavating the bones

and bringing them safely to the surface was not going to be easy.

The remains lay far underground in deep, inaccessible caves.

In places, the chamber entrance was less than 20 centimetres wide.

I put a callout on Facebook, saying,

"I need skinny scientists

"who are not claustrophobic, who were cooperative,

"who can work together

"in a dangerous and difficult environment."

I saw Lee's Facebook post,

actually, and, on a whim,

I applied for it, and 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 palaeoanthropologists that weren't claustrophobic,

and that would be able to fit into

a slot that was about 18 centimetres.

And that was very intriguing.

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.

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!

Then I got the e-mail that said that I, I got it!

And, characteristically, I bust out crying.

And just kept reloading my e-mail to make sure, refreshing it.

Just, like, "Really? It's really there? It's really there?"

Just five weeks later, Lee and his team of skinny scientists

were setting up base camp at the Rising Star cave system.

Working 25 metres underground would be difficult and dangerous.

Safety lines, lights, cables and cameras had to be installed.

A command post was set up from where Lee 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 2km 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.

Marina, Becca and Hannah had been chosen to go down first.

Still no one knows exactly what they will find.

The descent is difficult and, as I looked down,

I thought, "Oh, you know, I don't know if I can do this!"

So you start by descending down, you know,

a fairly narrow shaft and some tunnels.

You get down into an area here.

The team christened this the Superman crawl,

a stretch so narrow that they were forced to crawl on their stomachs

to get into the first main chamber.

This is what we call the Dragon's Back,

so that's the ridge climb

with a sort of four or five metre drop on either side.

At the top of the Dragon's Back, the scientists faced a vertical shaft,

dropping 12 metres down towards the hidden chamber.

Marina is the first to enter the deepest reaches of the fossil cave.

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

and a lot of excitement to be the first of the advanced 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 then I saw them enter this chamber.

We got the camera set up

and you could see their feet moving...

..and it was surreal.

The cave is beautiful, just geological beautiful,

and then you looked down and there was just a sea of bone.

And it was obviously just not regular bone.

So, yeah, it was amazing. Amazing.

expedition to recover the fossilised remains of our early ancestors.

The expedition leaders watched the recovery team

working in a narrow chamber, 25 metres below them.

And then the process started. The process of doing science began.

So we'll put pin number one right beside the mandible,

and that's where we'll concentrate.

OK. OK. Das ist super.

OK, thanks. Bye.

Yeah, that's perfect right there.

OK, good to start scanning? OK, scan.

Laser scanners and cameras are used to record the size,

shape and position of each precious bone fragment.

It's mapping right now.

Ah, there, they're coming, yeah.

I see what looks like a mandible in the middle there, on the right.

That looks fantastic.

Finally, it's time to bring up the first fossil - the mandible.

APPLAUSE All right! We have it.

You got the fossil. Yes, we have the fossil.

There we go, and we have everyone else.

Everyone's out, Rick is out safe. They're all out.

They went out. They're coming. Well done.

With the jawbone safely brought to the surface,

Lee Berger can get his first close-up look at the fossils,

and there is a surprise in store.

And when they opened that little box,

and we unwrapped this thing that they had 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 -

the ape-like creatures that eventually evolved into humankind.

Australopiths had large jaws and teeth,

but as they transitioned into the genus homo, their faces shrank.

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 unknown species that might

help scientists fill in the missing links between australopiths

and early homo?

He had these molar teeth,

and a very strange use of the front,

frontal part here.

And luckily, we got another piece, so, with these two pieces,

we have a hemimandible which is complete.

Then, we can put on the mirror image,

and we have a sort of outline.

This is pure confusion. We don't know what to make of it.

We realise 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 laborious task of piecing together the bones will not

only tell the team what these ape-men looked like,

it may also reveal new insights into how they lived.

Lee Berger knows how a find on this scale

could revolutionise our understanding of hominid behaviour,

because, remarkably,

this isn't the first time he's discovered a new species.

In 2008, he made a smaller discovery in the Malapa Valley,

just a few miles from the Rising Star site.

The Malapa find has blown apart one of the most controversial

theories about early hominids.

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' trackway,

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

Mostly overgrown. I came into this grove and found this little hole.

Lee had brought his nine-year-old son Matthew,

and his dog Tau along with him.

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

And with that, Matthew raced off into the bush here.

I thought he was going to get a chased 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,

cos I knew he'd found an antelope fossil,

cos that's pretty much all we ever find.

I saw a fossil.

I didn't think it was hominid,

I just thought it was an antelope, cos we find thousands of those.

I started walking towards him, though,

cos I had to see what he found.

And five metres away,

I realised that sticking out of that rock was a hominid clavicle.

I couldn't believe it.

And what I saw stunned me.

I climbed down the pit and looked right over here,

and there, sticking out of the wall,

was the proximal humerus of a hominid.

I couldn't believe it. I did my PhD on them, in fact.

I climbed closer, and as I got closer,

I realised 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.

One by one, they took out blocks of stone

they thought might have hominid fossils in them.

The blocks were all taken back to Lee's research laboratory

at the University of the Witwatersrand.

OK.

Lee's wife Jackie, a radiologist,

ran the blocks through a CT scanner,

allowing the scientists to peer inside.

Higher.

There you go, OK. That's good, yeah.

Inside one of the blocks, a stunning discovery.

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.

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.

This appeared to be an entirely new species.

Lee called it Australopithecus sediba,

after the wellspring near which it was found in South Africa.

The team radioactively dated the limestone layers in the Malapa Cave.

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.

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 that we were dealing with something that looked

like it would be a good climber, kind of an ape-like creature.

The next step was 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,

missing bones can be filled in with great accuracy.

Layer by layer,

a 3-D printer then slowly prints the ribcage in fine plaster.

Wow, beautiful. Yeah.

Finally, the skeleton is complete.

It is 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.

From the reconstructed skeleton, paleo-artist Viktor Deak

can start to create a lifelike digital painting.

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.

For the first time in almost two million years,

the face of Australopithecus sediba looks out on the world.

But what kind of creatures were they?

Sediba's bones would reveal secrets

that challenge one of the darkest theories about human evolution.

The fossilised remains of sediba are so well preserved

that they're giving us unprecedented insights

into how the creature lived.

And they may help to shed new light

on one of the most controversial theories

about our evolutionary origins.

In the 1920s, anatomist Raymond Dart was studying broken animal bones

that had been found alongside hominid remains.

He became convinced that the bones were used as weapons

by our primitive ancestors.

Dart had been a young medic in World War I.

He'd seen firsthand the barbarity humans are capable of.

Raymond Dart's experiences in the World War

may have coloured his interpretation of what these bones and teeth meant.

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,

this sort of killer ape theory of early humans.

Dart believe that the more aggressive of our apelike ancestors

abandoned their forest environments and moved into savannas.

There, they became meat-eating predators.

According to Dart,

this transformation into violent killer apes

was a key step on the long journey to becoming human.

MUSIC: Also Sprach Zarathustra by Richard Strauss

Stanley Kubrick made the killer ape theory frighteningly real

at the beginning of his epic film 2001: A Space Odyssey.

Broken animal bones quickly became weapons for control and conquest.

So will the fossil remains of sediba

back up Raymond Dart's killer ape theory?

Researchers at the Max Planck Institute in Germany

hope that sediba's teeth may tell them more

about what these animals ate.

The tartar that built up around the teeth may contain minute traces

of the foods that they were eating.

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,

whether food is harder or tougher,

but this is direct evidence.

That's exciting.

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 is little to back up Raymond Dart's theory

that they were killer apes.

Now, the latest discovery at the Rising Star caves

is revealing even more about our transition

from apelike forest dwellers into the first humans.

And the sheer scale of the find is becoming clear.

Good luck, everyone, have a blast! Thank you, will do!

All right, go get 'em! Good luck, happy hunting.

'It was probably a couple of hours into the first day

'when we realised it also wasn't one skeleton.' Another femur.

'If I remember right,

'it started with a second femur from the same side.'

Since there's never been a three-legged hominin,

we knew there were two

'and then there were three.

'I think it was by day two, there were four.

'And we realised we were in something very, very, very special.'

All right, good luck with that, we can wait to see you.

Initially, Lee had been expecting to find the remains

of just one individual. Now, the team saw evidence of many more.

It's everywhere! It's all strewn all throughout.

Not just the chamber,

but the passages leading to it are littered with bone fragments.

Oh, oh, oh,!

'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, my people were going, "We need more safes."'

LAUGHTER Whoo-hoo!

'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 hadn't yet seen the shark. And he's in there chumming

and all of a sudden, this gigantic shark appears and he goes,

"We're gonna need a bigger boat."

As the fossils accumulate in ever greater numbers,

a picture of the creature of the Rising Star Caves begins to emerge.

This is part of a juvenile pelvis. Yeah.

Thigh and hipbones tell them it walked upright,

but its gait was primitive.

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

not much bigger than a chimp's.

But the teeth and jaws seem more advanced, Homo like.

It's beginning to look

as if Lee has found a second new species from the dawn of humanity.

To prove it beyond doubt,

they must retrieve a treasure still buried in the cavern below.

The skull 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, OK?

Yes, yes, yes! If only because it gets it out of the way.

Not because you want it out to see it or anything.

There are a couple of reasons why we want to get it out.

One - the skull can tell you a lot.

It can tell you cranial capacity,

you 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?

We want to see that skull.

So there was all this tension

and it was a lot harder to extract than we thought.

The skull is extremely fragile.

Every tiny piece of bone has to be carefully retrieved.

Finally, the skull begins its slow ascent,

leaving the cave for the first time in possibly millions of years.

'And all of those scientists piled back in,

'all of the people that had 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

'where they knew there was a risk that it could get damaged.

'If dropped, it could get destroyed.

'Huge tension watching this passage on the cameras until there it was.'

There you go, folks, let's go get him.

'A great moment.'

LAUGHTER

We had some rocky moments.

Would you hate me if I took this before I hugged you? PLEASE take it!

Oh, well done!

It's the moment everyone has been waiting for.

They hope the skull fragment will be the tell-tale piece

to identify the creature as either an australopith

or a member of our own human genus.

Looking at a left frontal,

so it's this part, the orbit,

and then part of the brain case just 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.

It is indisputable Homo. Yes, yes!

The team's verdict is clear.

They have a new member of our genus

and, deep underground in the Rising Star chamber,

they are about to make a shocking discovery

about how these apemen might have lived and died.

from more than 12 individuals found in a deep cave in South Africa.

Now Lee Berger's team have to piece together and analyse these remains.

The Rising Star discovery is one of the most startling

and amazing discoveries in all of hominid evolution.

To have that many fossils in one place is unprecedented

and took everybody by surprise.

As the expedition winds down, the fossils are carefully transported

to the University of the Witwatersrand.

At a conference six months after the excavation,

researchers meet for an intensive analysis of the recent finds.

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.

The fossils suggest a creature unlike anything ever found before.

We are 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's sort of central -

the trunk and 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.

The new genus from Rising Star has been given the name Homo naledi.

It's 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.

Possibly 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.

And six months into the analysis of the hidden chamber

where they were found,

there's a puzzling new twist in the investigation.

It was pretty surprising that something completely normal

to every other excavation I've ever been in wasn't happening here.

We weren't getting anything else other than hominids.

There are no other animal remains in the cave.

All the fossils are human ancestors.

This is unheard of.

In every other hominid discovery,

they are found alongside the bones of other animals

that have wandered in and died,

or been dragged there by predators.

They're mixed with antelopes, generally in huge abundance,

and then you get, depending on the circumstance,

some carnivores and other bits and pieces,

and rodents, and this stuff that accumulates

when things die and are eaten and are dragged into caves.

So how did these hominid bones get into the Rising Star caves?

The chamber is very inaccessible, deep in the dark zone of the cave,

and with no entrance other than the long, narrow chute.

The team believes it was probably just as inaccessible

two million years ago.

It's starting to look as if the bodies might have been

intentionally placed there.

Could this possibly be some sort of burial?

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.

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.

Until now, the earliest known burials are from about 100,000 years ago,

and a much more advanced form of early human.

The team does not have an accurate date yet

for the fossils of Rising Star, but it seems unthinkable

that such a primitive looking creature

could be disposing of its dead.

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

Now, if we say that,

you have to understand it's a very controversial thing to say.

And so we approach it very conservatively.

We can show that there is no signs of predation.

We can show that there is no predator that accumulates

only hominids in this way.

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

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

and that's where we leave it scientifically.

We can say the best hypothesis we can come up with is

they were put there.

If this is true, its implications are profound.

The team now know that the Rising Star hominid

had a brain size just slightly larger than a chimpanzee's.

So, if in fact the Rising Star hominids are purposely

disposing of their dead, we're talking about

some small brained hominids who are doing this, and that begins

to change our thinking about the cognitive attributes

and the neural machinery that you need to engage

in that kind of behaviour, and that becomes really interesting.

If the skeletons had been intentionally disposed of,

it would indicate highly advanced social behaviour,

at a much earlier stage in our evolution

than had previously been thought possible.

And that here, at the dawn of humanity,

the complex social bonds that mark us out as human

had already begun to take shape.

As yet, the question of exactly how these fossils

fit into the story of human evolution is not clear.

The remains from Malapa and Rising Star

may or may not prove to be our direct ancestors,

but they point us towards a new way of thinking about our origins.

We have a 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.

Evolution is bushy.

There are different experiments,

populations try different adaptations,

they try different ways of being about the world.

These earlier finds and the new naledi species

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.

Thanks to the work of scientists like Lee Berger,

we know some of these varieties of late Australopith and early Homo

existed simultaneously, and some may have been interbreeding.

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

and what happens 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 the 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 is the most responsible

for us being here.

The recent finds on the plains of South Africa are adding

a vital new chapter to the story of our origins.

The tantalising 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.

Subtitles by Ericsson