Original subtitles

(birds tweeting)

On this hill nearly four million years ago,

Little Foot, one of our early ancestors, wandered.

Today the excavations at Sterkfontein Caves

near Johannesburg in South Africa

have provided us with one of the richest sources

of knowledge about our origins.

So much so that the area has become known

as the cradle of mankind.

(dramatic music)

Over 800 early human fossils have been found

here to date, including the most complete skeleton

of its kind in the world, Little Foot.

Today the Sterkfontein Cave system is surrounded

by grassland and scrub,

and was just another koppie or small hill

until the first fossils were found here in the 1930s.

But 3,670,000 years ago, in the time of Little Foot,

the Sterkfontein region of South Africa

was more like the Central African forests of today.

There were massive trees with lianas or vines

clinging to their towering trunks,

and of course, there were many apes.

Apes all sharing the forest and its food

and shelter from the formidable array

of predators on the ground.

Amongst them were our ancestors.

We know more about the environment that

Little Foot lived in then because

fossilized material from her days

has been found in the caves, along with her own fossils.

With a lot of Australopithecus fossils,

we find fossil wood, and that fossil wood

has been identified by Professor Marion Bamford

of this Evolutionary Studies Institute,

and she's identified most of those fragments

as belonging to a species of liana,

Dichapetalum mombuttense, which now only grows

in tropical West and Central Africa.

It's a very interesting piece of wood

because it's a liana.

Now, lianas have a very special structure,

so we know it's a vine, and vines don't grow

upright by themselves.

They have to have something to grow over.

In other words, large trees.

So although we don't get the large trees preserved,

we get the vines, which means that there were

large trees at that time, and that fits in

nicely with the animals that we've found there,

because they were hoard of monkeys

that are arborial, and so the hominids at the time,

and even earlier than that, were growing in

a much more wooded environment than we have today,

and the hominids would have been living in there

or associated with there, and they fell into

the little cavities that are opened

down to the caves, along with the woods,

along with the fauna and all sorts of bits and pieces.

The Sterkfontein cave system is still

pockmarked with dangerous holes,

so now walkways protect visitors and scientists.

In the time of Little Foot, 3.6 million years ago,

covered with lush vegetation, the holes surrounding

the vast cave system were often a death trap.

Sterkfontein is almost daily yielding

important new discoveries related to our origins.

The considerable excavations over decades

have yielded famous discoveries,

including the Australopithecus africanus

and prometheus species, not least of which

is that of Little Foot.

At once tragic and ironic, the fact

that Little Foot fell into one of these holes

leading to the caves below meant that

her skeleton was preserved mostly intact,

safe from the ravages of predators and scavengers

for millions of years.

The skeleton was sealed mostly within breccia,

a type of natural concrete which had covered

and hardened over the bones for nearly four million years.

To reveal her fossil remains within this

was little short of a miracle, a miracle

that took over 25 years of exploring

and extraordinary patience, working through the rock

in fractions of millimeters.

Even more astonishing was that evidence

of Little Foot had been discovered but overlooked

for some 15 years before this at Sterkfontein.

The story of Little Foot nearly goes back to

before my time, in 1978 to 1990.

Lime miners' rubble that had been

blasted out as early as the 1920s.

Crushed limestone was used then as a building material,

was removed from a very deep cave at Sterkfontein

known as the Silverberg Grotto.

Teams were sent in to remove the blasted material.

The reason they wanted to take this material out

was that it was full of fossil bone,

and Phillip Tobias thought that they might find

something older than the hominids

or Australopithecus that they'd been finding

at higher levels at Sterkfontein.

He thought they might find something as old

as the famous Lucy from Ethiopia.

This sculpture of the late

Professor Phillip Tobias stands at Sterkfontein

in memoriam as the team leader of the excavations here

for 50 years, establishing the caves

as a World Heritage Site in 1999.

Tobias' hunch about discovering a much older

hominid deep in the caves was correct,

but would only be realized years later

through the detective of Professor Ron Clark,

for the secret lay not in a cave, but in a story.

So they removed all this rubble

and they processed it over the years.

It remained like that for a long time

until 1994, when Phillip Tobias asked me

if I could do an in situ excavation

in that deep underground cave.

We got many fossils of monkeys and of carnivores,

but very few bovids.

Bovids are hoofed animals,

including ancient buffalo and many antelope species.

And I thought this is very strange,

because up in Member 4, we find a lot of bovids

and also a lot of Australopithecus,

but down here we hadn't found a single

tooth of Australopithecus, the ape man.

The various Australopithecus

species found at Sterkfontein, Australopithecus

meaning a southern ape, were all

before the various Homo species,

which are believed to be more directly linked

to early humans.

So I went to the boxes of fossils

that were in our shed at Sterkfontein,

in our big store room there.

In the store room, Ron Clark

was hoping to find some fossils of bovids

or cloven-hoofed animals.

Instead, he found something that would

change his life and the history of our origins forever.

I took one of the boxes, put it on the desk,

hoping I would find some bovids in there.

I took out a bag and tipped it on the desk,

and to my surprise, I found this

among the animal fossils.

Ron Clark had found the very first

bone of Little Foot.

This is a hominid talus, an ankle bone.

How was it that this was missed?

And then, to my delight, in the same bag

I found the bone that went in front of it,

the navicular, and then the bone that went

in front of that, the medial cuneiform,

and then part of the first metatarsal,

leading down to the big toe.

It was unusual to find four articulating

foot bones like that in Sterkfontein.

Normally you find just one foot bone

if you're lucky, but to find four together was unheard of.

That was exciting, but then, some years later

in May 1997, I chanced upon more of the same foot,

and the way that happened was interesting.

Ron Clark found the next link

in the Little Foot discovery in the hominid vault

here at the University of the Witwatersrand

in Johannesburg, South Africa.

And to my surprise, I saw a box there

that was labeled as containing monkey fossils

from a lime miners' dump number 18.

And the first bag I took out, through it

I could see a little white bone

that I recognized as a foot bone of a hominid,

and then another one, and then another one.

I also found part of a tibia, and I found

part of a fibula.

So I had parts of the foot and lower legs

from left and right, and that convinced me

that the rest of the skeleton must be in the cave,

and that these bones had been blasted off by lime miners,

leaving the rest of it still there

in the cave infill.

So I thought, wouldn't it be wonderful

if we could find the rest of it?

And I gave this cast to Stephen Motsumi

and Nkwane Molefe and said, "Go with torches

"down into the cave and see if you can find

"anywhere that will fit it."

Well, this was a seemingly impossible task,

because the cave was vast, it was dark,

it was deep, the surface of the ground

was irregular, rock-strewn and dusty.

Anyway, they took me at my word,

and miraculously, after one and a half days

of searching in that cavern, they found the spot,

and when I next went down there,

Stephen told me that they'd found it,

took me down, showed me, and next to it

I was able to fit this one on as well.

After five years, Ron and his team

now had the complete Little Foot.

Stephen Motsumi and Nkwane Molefe

had pulled off another miracle

on the long journey to Little Foot.

The few bones he now had told Ron a lot.

The first was that Little Foot walked upright like us.

Now, Ron and the team wanted to find the rest.

We began chiseling away the enormous rocks

that were above this.

There were some huge rocks of dolomite and chert,

and we were chiseling that away to get down

to that level.

We uncovered much of the lower legs

after several weeks, months of work,

just carefully, carefully cleaning away the rock,

and when we got close to the bones

we used what we call an air scribe

which is a pneumatically-driven needle.

The air scribes allowed the team

to uncover the bones from tons of rock

over years without damaging them.

Experienced researchers learn to tell rock from bone

by color, texture and shape.

So we uncovered the lower legs.

When we got to the middle of the thighs,

there was no more.

And I asked them, "This is impossible.

"How can there be just the lower legs

"and not the rest of the skeleton?"

So we went on chiseling away these big rocks

and breccia cave infill, right up to the roof,

month after month, and found nothing,

until I realized that there was a cavity

underneath these legs at a lower level,

and I concluded that what must have happened

is that millions of years previously there'd been

an ancient collapse, and the upper part

of the body had collapsed down to a lower level

and then been sealed in by a

very thick flowstone, stalagmite.

Ron thought that possibly

part of the body, with the upper legs and skull,

had dropped away over the millions of years

to a lower part of the cave.

His instinct was right.

And it had been sealed in by that,

which went over the upper part of the body

and beneath the lower legs.

So I said to Stephen, "Let's chisel through this."

And we chiseled and chiseled, and...

One day, miraculously, again, his chisel struck bone.

There.

And it uncovered that.

And I thought, what on earth is it?

Is this a cast?

It's like a...

Ron and his team had uncovered a skull

that would change everything.

Ron's instinct had led them to an unprecedented find,

the complete skull of Little Foot,

its left side partly compressed by the weight of rock.

Not only was it the most complete skull

of its kind ever found, it was even more astounding

in that it still had a complete set of teeth

or dead tissue.

This was the first time ever that a complete

adult skull of an Australopithecus had been found.

Years of dedicated

millimeter by millimeter progress through the rock

were revealing their rewards, and there

was more to come.

That was the beginning of the excitement that was to come.

We went on cleaning away very carefully

with this little air scribe, month after month.

The air scribes would remove

the hard rock from around the soft fossils

with scalpel-like precision.

And then we worked further up slow,

and we got the arm, and we got ribs,

and we got vertebrae, and then at the lower level

we got the pelvis and so on.

(slow, atmospheric music)

It had been a miraculous journey

with the discovery of the first foot bones alone

from 1980 to 1997, and from then on until

the final skeleton in 2017.

Now the world had a comprehensive intact skeleton

from one individual, and the learning would begin.

And the learning started from the very beginning

with the first bones.

Starting with the big toe, Ron discovered

the first notable difference about Little Foot.

When I found the first four bones, I had already

determined that it had a very interesting development

here, this joint, in that it had some mobility.

So it had a slightly mobile big toe,

not as much as the apes, but slight mobility

which would have assisted it in climbing in trees.

Little Foot's intact arm and hand

revealed even more secrets.

So a beautiful arm.

What this told us, it's the first time ever

that a complete hand had been found like that,

and still attached to the arm.

The hand was exactly like ours, with long thumb

and short fingers.

It was not like that of the apes,

which have a shorter thumb and long fingers

because they suspend themselves from branches.

They also have long arms to assist them

in swinging in trees.

When they come down to the ground,

they use those long arms and long hands

as supports for walking.

This one didn't have that.

It had arms that were like ours, relatively short.

It had a hand that was like ours,

and when I was eventually able to reconstruct the legs,

I could see that the legs were actually

longer than the arms, just like us.

This, a human ancestor, had proportions similar to us,

and it walked fully upright as we do.

And it would have to climb in trees for two reasons.

Firstly, to get at fruits, which were up there.

And secondly, to get away from the carnivores

that were on the ground.

We know that at the time when Little Foot lived,

there were many, many very big carnivores.

There were several types of saber-tooth cat.

There were also the leopard and the lion

that we get today, although some of them

were larger than those that we get today.

And there were several different types of hyena,

so it was a very, very (laughs) unhappy environment

on the ground for a small hominid or Australopithecus.

Now that we have Little Foot's

full skeleton, we now have an accurate measure

of her height compared to modern humans.

And I'm sure that at night, Little Foot

would have wanted to nest up in the trees.

(birds singing)

Learning from Little Foot continues.

Her pelvis, with its greater sciatic notch,

indicates that she was probably female.

Her teeth have let us know her age of about 35 years.

Her brain, with its complete endocast and skull,

will hopefully answer questions about how

she might have thought or felt,

and about her cognitive processes.

The scientist beginning their journey

into Little Foot's brain is Dr. Amelie Beaudet

of the University of the Witwatersrand.

Yeah.

Little Foot can be used as a reference

for understanding evolutionary patterns,

because we have this individual which is

very well-preserved at a specific time,

so 3.67 million years old, and the specific

geographical context, so we can really use it

as a reference for understanding later evolutionary changes.

We extracted two very important structures from the skull.

One was the brain endocast that we can see in red here,

and here's the inner ear, and that,

because we know that those two structures

could be very informative to know about how

Little Foot lived at that time in South Africa.

Today Little Foot lies in place of honor

in the hominid vault in the Evolutionary Studies Institute

at the University of the Witwatersrand,

freed from the rock that held her fast four million year.

Hopefully, she will teach us even more about ourselves

in the time to come.

(ethereal, atmospheric music)