National Geographic: Mysteries of Mankind Page #2

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of spoken language.

But genetically humans and

chimpanzees are 99% identical.

Chimps may even be more closely related

to us than they are to gorillas.

In 1960 Louis Leakey,

with uncanny intuition,

sent a young woman into the field

to study chimpanzees.

Jane Goodall's 27-year old study has

become a classic

and confirms Leakey's conviction that

chimps have much to teach us

about the behavior of early humans.

Understanding of chimp behavior today

helps us to understand the way in which

our early ancestors may have lived.

Because I think it makes sense

to say any behavior shared

by the modern chimpanzee

and the modern human

was probably present

in the common ancestor.

And if it was present in the common

ancestor, therefore in early man.

A mechanical leopard was instrumental

in an experiment

with chimpanzees conducted

by scientists

from the University of Amsterdam.

Anthropologists have

long puzzled over how

our ancestors defended

themselves against predators.

How could such small creatures,

not yet intelligent enough to make

stone weapons, have possibly survived?

Leopards are natural predators

of chimpanzees.

Here, as the chimps attack,

we catch a glimpse

of how our ancestors,

having left the safety of the trees,

may have first met the challenges

of life on the ground.

Once the leopard is decapitated,

the chimp may not comprehend

that it is '"dead,'"

but it clearly knows the enemy

is no longer a threat.

If a chimpanzee has the intelligence

to defend itself with natural weapons,

it seems likely our early ancestors

did the same.

The chimpanzee has never

become an habitual upright walker.

Why did we?

Upright walking is so fundamental

we seldom think about it,

and yet it is one of the crucial ways

we are set apart

from all other mammals on earth.

When did our ancestors take that first

tentative step out of the trees

to brave the vast African landscapes?

Lmportant answers would be found in

the Afar Triangle region of Ethiopia.

Here, in 1974,

an international expedition

of 15 specialists

headed out to

the remote badlands known as Hadar.

Co leader of the team,

Dr. Donald Johanson

describes himself as superstitious.

After two frustrating months

on the sun scorched slopes,

he woke up one morning feeling lucky

and so noted in his diary.

Later that very day

the team discovered bones

that made headlines around the world

at the time the oldest,

most complete hominid ever found.

To anthropologists

who usually consider themselves

lucky to recover a tooth

or a broken fragment of bone,

this 40% complete skeleton

was a bonanza.

Nicknamed Lucy,

she quickly became the obiect

of intense study.

What is most exceptional

about a skeleton

as complete as Lucy

is all the information that

we as anthropologists can glean

from a skeleton like this.

For example, looking at

her femur or her thigh bone,

which is only about

we know that she was no taller

than three and a half or four feet.

Now that brings up the question

of was it perhaps a child?

If we look at the state of development

for example, of the third molar

or the wisdom tooth,

it is fully erupted and

is already beginning to wear.

So that relative to modern humans,

she was an adult when she died.

We're able to tell from

the weight bearing area

of the hip socket, for example,

that she probably only weighed

about 50 or 55 pounds.

From the size of the brain case,

there is enough

of the brain case preserved

to suggest to us

that the brain was very small

about one fourth the size

of a modern human brain.

Historically, large brains have been

considered the fundamental human trait.

In the 20s when Raymond Dart suggested

a small brained creature walked upright

he had only a skull to work with.

Here was a significant portion

of a skeleton a creature

with some very ape like features

that walked upright.

Lucy had an ape like brain,

a human like skeleton,

and teeth both ape and human like

a startling mixture of traits.

Yet clearly she was a hominid,

a member of the family of man.

Returning to Hadar the following year,

the team combed the slopes hoping

to discover newly exposed fossils.

They never dreamed they would find

anything as exciting as Lucy.

But the Johanson luck proved even

better than the year before.

We have the femur and

the foot and the knee!

They had come across the

first fragments of 13 individuals,

possibly members of the same band.

They may have all perished together

perhaps in a flash flood.

The fossils from Hadar

and similar ones from Tanzania

represent from 35 to 65 individuals.

Based on the abundant evidence,

Johanson and

his colleagues felt confident

in announcing an entirely new species.

They called it

Australopithecus afarensis

and put forth

the still controversial idea

that it is the common ancestor

to other Australopithecines

who eventually died out,

as well as the line

that led to true humans.

In the laboratory fragments

of skulls and iaws

from several males were combined

into a composite plaster skull

by Johanson's colleague, Dr. Tim White.

After initial discovery and analysis

scientists rarely work

with an original, fragile fossil.

In fact,

the fossils are usually returned

to the country where they were found.

But these durable casts

are exact replicas

down to the most minute details.

In Alexandria, Virginia,

the composite skull begins

a magical transformation

in the hands of anthropologist

turned artist, John Gurche.

Gurche has been fascinated with

human evolution since childhood.

Today he combines the talents

of an anatomist

with those of a master sculptor.

His workroom is a cross

between an artist's studio

and a scientific laboratory.

Placing the eyes

is often a special moment.

I base the position of the eyes

on scientific data,

but there's also often a mystical side

of it as well.

That is often the moment when I begin

to feel that I'm being watched

by the thing I'm working on

that it is not so much a thing

of clay and plaster,

but is actually a living being.

What I really want to do is get

at the human past,

and having the scientific data

behind me

makes it much more rewarding for me

because I can believe

in what I'm doing.

I can believe that the face

that's developing

in front of me is very much like

the face

of the individual that it

actually belonged to.

The really fascinating thing

about working

with Australopithecines is

that you have something that's right

on the line between being human

and not human.

You have a lot of features

that are ape like

and yet it's in the process

of becoming human.

The reconstruction will take

Gurche more than two months.

It is painstaking,

arduous work that often continues

well into the night.

I'd really like to be able

to make the claim

for this kind of

work that it's a hard science.

Unfortunately, it's not.

It's as good as it can be

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