Neanderthals Are Us - Ep. 460 | Wisconsin Public Television

Neanderthals Are Us - Ep. 460

Neanderthals Are Us - Ep. 460

Record date: Jul 21, 2010

John Hawks, Assistant Professor, Department of Anthropology, UW-Madison. John Hawks explores the existence and disappearance of the Neanderthal during the course of human evolution. He also explains the anatomical difference between Neanderthals and Homo sapiens.

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Episode Transcript


>> Welcome to University Place.
I'm Norman Gilliland.
About 80,000 years ago when
human beings first migrated from
Africa to the Middle East, they
found that someone else was
already there.
Neandertals.
For about 10,000 years Homo
sapiens and Neandertals
coexisted, and then for some
reason the Neandertals
disappeared, but why?
Well, with the key to that
mystery is our guest today, John
Hawks.
He's an evolutionary geneticist
at the University of Wisconsin
Madison.
Welcome to University Place.
>> Thanks for having me.
>> Well first we should figure
out what's the difference
between a Neandertal and a human
being.
And I suppose we should even ask
before that, what's the
difference between a Neandertal
and a Neanderthal?
>> Well, Neanderthal and
Neandertal.
Well, this is so interesting
because even people who are real
familiar with anthropology, they
differ on the way to say this
word.
And it's for obscure reasons
that there came to be these
different ways of pronouncing
it.
The original Neandertal fossils,
the ones that were recognized to
be something different from the
rest of us, were found in
Germany in a place that's a
little bit outside of
Dusseldorf, and it was called
the Neandertal.
Tal meant valley.
And it was because there was
this guy who lived there named
Neuman and he was sort of a
hermit and people started
calling it Neuman's Valley and
he styled himself as being a
real intellectual so he rendered
his name in Greek and called it
Neander.
So we've got Neandertal.
Well, now the site is completely
gone because they were digging a
limestone quarry at the time,
and the reason why they found
the bones is that they're
digging out the limestone and
what was inside of a cave was
just junk as far as the quarry
was concerned.
Well, eventually the limestone
is gone.
This is like a parking lot.
And in the last five years
really the museum that's there
sort of renovated what was once
really junky looking into a nice
little meadow, and you can see a
monument where the site was.
It's very nice.
But it's completely gone.
Well, in the late 19th century
Germans changed an archaic form
of spelling, TH into a T.
So although it came into English
as the TH, the old version,
in German it's now just a T.
And a lot of anthropologists
changed to go along with the
Germans.
Mainly those of us who thought
that Neandertals had something
to do with our ancestry because
the TH version of course came
into English and started
suffering this terrible fate
because everything that you
don't want to be is Neanderthal.
That's like, wow, if you call
you a Neanderthal, this is not
saying you're the valued
ancestor.
>> Some kind of throw back.
>> Exactly.
So we've got tal and thal.
>> And what is the difference
then so far as we know today,
and we're discovering a lot I
gather, what is the difference
between Neandertal and Homo
sapiens?
>> Well if we look classically
at their anatomy, what we found
was fossils and in many cases
subfossils, they hadn't
mineralized yet, so skeletal
materials, and what became
obvious about them was the ways
that they were different from
us.
And so if you look at their
skulls, they tend to have a real
projection above their eye
orbits, it's called a brow ridge
or a supraorbital torus.
Their skulls tend to be quite
long and their foreheads slope.
Their faces are really big
compared to most living people.
The big faces, relatively big
teeth, but those faces sort of
project forwards.
So it's almost like their face
is lifted up in front of their
brain.
Whereas, most living people have
faces that are sort of tucked in
underneath their brain.
Their jaws tend not to have a
chin.
And if we look then post
cranially, well their bones are
different from ours in some
respects also.
If you look at a femur bone of a
Neandertal, for example.
>> Let's look first just by
comparison at the modern human
skull.
>> Here's the modern human
skull.
A very rounded forehead.
Face tucked in underneath of the
brain case.
>> I assume these are
comparative males then because a
female skull would be
a different shape.
>> Exactly.
You've got the robusticity.
Men are sort of bulkier, more
robust than women.
And Neandertals differ from us
in that respect, but also they
have these real distinctive
anatomies.
And then there are little things
like they tend to have a little
groove on the back of their
skull.
We have no idea what it's for
but it's there.
>> Is it a muscle of some kind,
a muscle attachment?
>> Well it's a resorption area
where you can feel the back of
your skull there, there's no
muscles on top of it, but their
bone just tended to resorb a
little bit.
Why that happened, we have no
idea.
>> What about that great
sagittal crest that men have
that women tend not to have.
>> Well the sagittal crest is
something that earlier hominids
had in the middle of the skull.
But this supraorbital torus is
something that's real
distinctive about modern humans
who tend really not to have
this.
It is quite rare today to see
somebody with a brow ridge that
goes right across the front of
their face.
>> You probably don't
necessarily want to meet
somebody on a dark night like
that.
>> Maybe not here in Madison.
Some parts of the world it's not
so uncommon.
It's a trait that still varies
today.
As to why that's there, it's
sort of a mystery.
Some of these things we think
are just side effects of genetic
changes.
>> Kind of rambled, tumbled
effects.
>> Exactly.
Some other things are probably
functional in some way.
>> You mentioned the bones, some
of the bones and the difference
there.
This we have with the upper leg
bone.
>> Yeah, this is the thigh bone
of a Neandertal, a femur.
And if we look at any of the
long bones of their arms and
legs, what you see about
Neandertals is that they're
really heavily built.
Now, it's a real common
misconception that Neandertals
are big like professional
wrestler types.
They're not.
The average height of a
Neandertal man was something
like five foot five, five foot
six inches.
So they're not.
>> Any taller than Homo sapiens
of the same time?
>> They're a little shorter, a
little shorter but not a lot
shorter.
And if you compare Neandertals
to early agricultural people who
had not as good food to eat,
they're about the same height.
So we're talking about hunter
gatherers.
>> How about running, how would
you compare them as runners if
they're that stocky?
>> Now if we look at their
proportions, they are generally
stockier than us.
So their distal segments, the
shin versus the thigh or the
radius and ulna versus the
humerus, they tend to be short.
Their limbs tend to be a little
shorter.
Because their bones are over
built and curved, we think that
they were more powerful.
They were certainly capable of
resisting more force than the
average human.
And all that attests to a real
muscular strength adaptation.
So if we compare them and us
running, we're not talking about
distance runners with these
guys.
I mean they are, in that sense,
built like wrestlers, not
professional wrestlers but
college wrestlers maybe.
And if you compare them to other
kinds of hunter gatherers, they
are definitely bigger, they have
more energy output and that
means that they lived a
lifestyle, which in the northern
frontier of human habitation at
that time, a lifestyle that took
a lot more energy.
That's the real difference
between them and us is in
energetics and ultimately the
effects that has on their
behavior.
>> When they moved out of
Africa, and they got there
before Homo sapiens as we
indicated a few minutes ago, any
kind of settlements or are these
discoveries that we're making of
Neandertal sites, I'll call
them, are those just one night
stay over places or what kind of
a system of living do they have
in these early sites?
>> Archaeologists have a clever
strategy and that is find
somewhere that you think humans
would have been and dig there.
And so what we tend to find with
Neandertals is we, of course,
find a lot of them in caves but
that's because the
archaeologists know that these
caves attract all kinds of
animals in the landscape and
humans are no exception.
And so you go to a cave and you
dig and you're likely to have a
sort of large deposit of
undisturbed sediments, and we
learn a lot about their behavior
that way.
But they didn't live in these
caves.
They came there, they'd stay for
a few nights sometimes, but they
weren't cave dwellers in that
sense.
This cave that we've got a
picture of is, to my mind, the
most beautiful of all the
Neandertal sites.
It's in Vindija, Croatia.
It's right on the Slovenian
border, and you can see from
inside the cave looking out it's
green.
Croatia is a lot like Wisconsin,
especially the driftless area of
Wisconsin, the part that wasn't
glaciated.
It's got hills, it's got a lot
of trees.
And looking out of this cave
there are strawberries that grow
around it.
It's a really nice place.
And the Neandertals used these
places to sort of hide for a
couple days.
They would stage their hunting
trips probably out of these
places and open air sites, but
they didn't tend to return and
stay for weeks or months on end.
They were very mobile people.
They had to follow the animals.
With Neandertals in particular,
imagine that you're hunting,
as they did, large mammals.
We're talking about
bison and horses.
They didn't have bows and
arrows.
They didn't have javelins.
They had big long wooden spears.
Sometimes with a point glued on
the top of it.
>> A stone point.
>> A stone point and they would
have to jump on the animals to
kill them.
Imagine you've got a spear and
you're going to jump on a bison.
>> You'd have to be pretty
sturdy to take that kind of
abuse.
>> Absolutely.
There's a site called Krapina,
which is also in Croatia, where
they're hunting woolly
rhinoceros babies.
Wooly rhinoceros babies tend to
come with woolly rhinoceros
mamas.
>> I don't think you can mention
anything too much more fierce
than that.
>> So with Neandertals, their
technology limits them, in that
sense.
They're living a hard lifestyle.
But also when we think about the
limitations that are on them,
think of the strategy that works
for this.
You've got to know what the
animals are going to do.
You really got to have the jump
on them.
So Neandertals are like ambush
hunters.
They're a lot like mountain
lions who are taking all ages of
prey.
It doesn't matter which animal
comes along because what's
important is that you have the
position that you can surprise
them.
And the Neandertals are using
their landscape this way.
>> So they would be migrating
seasonally with the game.
>> We think they were.
And yet they have this immense
familiarity with their
landscape.
You really have to know where
the good places are.
And when we find caves that were
recurrently occupied by
Neandertals, they come back to
this place again and again,
sometimes they're hunting the
same kind of animal again and
again.
So we get caves where 70%-80% of
the animal bones are horse.
And other caves where it's the
same proportion bison.
And it's got to be because not
this is the place where the
bison were but because this is
the place where they had a good
strategy to get the bison.
And for whatever reason the
landscape offered an opportunity
for that or they were there at
preferentially that time of
year, whatever the reason,
that's what they were able to
do.
>> They had bigger brains than
Homo sapiens?
>> Neandertal brains, for men,
average a bit over 1600 cubic
centimeters, and that's a big
brain today.
There are humans who are that
size.
The range in normal-sized brain
men goes from something like
1,000 cubic centimeters to
something like 2,000.
So Neandertals are upper end of
that range.
The average today in Europe for
men something like a little
under 1400.
So they're quite a bit brainier
than us in terms of mass.
Of course we don't know what
difference that makes to
behavior.
>> So, the differences between
Neandertals and Homo sapiens
really have mostly to do with
body structure, so far as we
know.
Is there anything we can tell
from DNA and how similar was
their DNA to ours?
>> So the really cool thing, the
reason why we are really excited
about Neandertals now is that
we've got a draft of their
genome.
And I'm showing you this bone,
this is a little piece of a shin
bone.
And it came from that cave,
Vindija Cave.
When this was found along with
the archeological excavation of
the cave, they tossed it in a
box with the animal bones.
You can see this little piece of
bone is not obviously human
looking.
>> Nothing too impressive about
it at first glance.
>> Yeah.
If you look very carefully at
the anatomy of its surface and
considering the size and
everything about it, it doesn't
fit in with any of the animals
that were living around there
then.
It looks like a human bone from
that aspect.
And it was Tim White who
discovered Ardipithecus, he's
famous for that, who went back
through these boxes of fauna and
found this bone there.
Turns that this bone has the
best preservation for DNA of any
bone that we found of
Neandertals yet.
So it's really exciting that
here's a piece of anatomy that
is completely useless to us,
from the standpoint of
interpreting Neandertals, it's a
piece of bone, it's a
Neandertal.
That's what you can say about
it.
>> Nothing in terms of the
skeletal context.
>> Out of this one bone comes
now more knowledge about
Neandertals than we've ever
excavated out of the ground
before.
Because we've got 20,000 genes
and three billion base pairs of
DNA and counting coming out of
this bone.
To date, they've got large
amounts of the genome of two
other individuals from this site
and a couple other Neandertals
from other places, and we know
quite a bit about the
mitochondrial DNA, which is a
very small fragment of our
complete genome but it's real
variable so it tells us
something about population
structure, we've got that from
about 20 Neandertals from
different sites.
So we know a lot about their
genetics now.
>> And what are we learning?
>> For me as an anthropologist,
the coolest thing is that we're
part Neandertal.
I'm flabbergasted to be able to
say that now.
>> That's part of the answer to
the question what became of
them.
>> Absolutely.
When we look at the human genome
and the Neandertal genome, they
differ on average in such a way,
we tend to, in comparing
genomes, how are we going to do
it?
We can count the number of
differences.
We could say this is X
proportion different.
An easy way to talk about
difference is time.
Because if you imagine that we
have ancestors, those ancestors
lived at some time and they have
descendants today and those
descendants are cousins of each
other, basically, then what's
interesting about the genetics
of the cousins?
Well, one thing that's
interesting is how long ago that
common ancestor lived.
That gives us an index to talk
about how different they are.
A human gene and a Neandertal
gene, on average, had an
ancestor about 800,000 years
ago.
Now it doesn't mean that the
population that was ancestral to
us and Neandertals lived that
long ago.
Because if we look in humans
today we can ask the same
question.
Your DNA and my DNA, how long
ago on average did we have an
ancestor in common?
The answer to that is over
500,000 years.
>> That far back?
>> That far back.
And looking at humans around the
world, how long ago did our
genes differentiate?
Well some of them very recently.
Obviously we have some genes
that have come from ancestors
who lived in the first
agriculture days.
>> You mean just a mutation that
occurred then?
>> Just a mutation that occurred
then that today is common.
So lactase persistence.
This effect that Europeans today
can drink milk when they're
adults, that's a mutation that
happened 8,000 years ago.
>> Because the default was to be
lactose intolerant for humans.
>> That's right.
So everybody today who has that
mutation, we can say one thing
about them.
They definitely have an ancestor
in common that lived 8,000 years
ago.
So some genes are very recent.
Other genes, a long, long time
ago.
If you're blood type A
and I'm blood type B,
I'm not, I don't know
what you are, but as an example,
somebody who is type A and type
B, those two versions of that
gene diverged from each other
about three and a half million
years ago.
So what we're saying is that if
we know that two people carry
different alleles of that gene,
we know that they didn't have an
ancestor in common for that gene
for the past three and a half
million years.
Now that's Australopithecus
time.
We're not saying that...
>> You go back much farther than
that and be in the human family.
>> That's right.
It's not that the type A and
type B people diverged and
became different populations,
it's that those variations were
maintained in this population.
The human Neandertal ancestors
were maintaining variation too.
So we think that whatever
divergence there was between our
population, which mostly is
derived from Africa before
80,000 years ago, and the
Neandertal population, which
mostly lived in Europe
stretching across sort of the
southern tier of western Asia as
far as Uzbekistan, so going into
central Asia, those populations
look like they diverged
something like 300,000 years
ago.
>> So we think Neandertals left
Africa when?
>> The first Europeans got there
1.2 million years ago.
We've got a really good skeletal
record of Europeans after about
600,000 years ago.
We've tended to think that those
people were the ancestors of
Neandertals.
It's now clear that the
Neandertals are getting genes
coming in from presumably
Africa, but possibly other
places too, up until at least
300,000 years ago, maybe later,
and then after that time,
sometime after, as you said,
80,000 years ago, humans
emerging from Africa mixed again
with that population.
So we find this evidence of
mixture in their genome.
>> Do we see any evidence of a
combat between Neandertals and
Homo sapiens?
>> A lot of people want to know
what was this interaction like?
And Neandertals we already know
lived sort of hard lives.
>> They weren't necessarily kind
to each other in the first
place.
>> Yeah, I described this
hunting method that they have,
and that has its risks.
This skeleton is from a site in
Iraq which is called Shanidar
Cave.
It's in the northern part of
Iraq.
>> It's very famous.
>> And the most famous skeleton
from this cave, Shanidar 1, the
most obvious thing about him is
if you look at his arm bones,
and I've got the two upper arm
bones here, the humerus, they're
asymmetrical.
One of them is normal looking
and the other one is wimpy and
withered.
It's because his arm was
amputated at the elbow.
And he lived with one arm.
He also looks like he was
blinded in one eye.
You can see looking at the front
of his skull there that the eyes
are not symmetrical.
It's because one of them was hit
by something real hard and the
bone fused in an abnormal
position.
>> What was the age of this
individual when he died?
>> This guy, who is one of the
oldest Neandertals that we know
of, died sometime in his
mid-40s.
>> Which sounds incredibly old,
especially for somebody with
part of an arm gone and probably
blind in one eye.
He must have had some kind of a
social network to sustain him.
>> He lived this way for a long
time.
You can see the evidence.
That arm took a long time to
atrophy to the point that it
was.
And he healed from his wounds.
So there's clearly some
elaborate social network that
enables them to survive, and
we've wondered for a long time
why.
Do they have some kind of
ideology or knowledge that
they're passing on that values
these older individuals.
It's very possible.
>> Do we have sense of
aesthetics, Neandertal
aesthetics?
>> What's interesting is we used
to think that when modern humans
show up on the scene, especially
in Europe, where after 30,000
years ago there are these
beautiful painted caves.
>> Altamira and other places in
Spain.
>> The earliest one is Chauvet
Cave in France.
Lasco is maybe the most famous.
It's a little more recent, about
23,000 years old.
But these caves represent an
artistic expression that was
thought to be real unique to
modern humans.
But digging in the Neandertal
sites, every so often you find
something interesting.
We now know that Neandertals
were making beads and drilling
holes in animal teeth to use as
pendants.
We find that they were
collecting shells and carrying
them inland so they were valuing
these things and trading them.
In one case in Portugal we've
got a site, I've got a picture
of one of the shells here, we've
got a site where they painted
shells.
So this is a natural shell that
on one side has got a natural
coloration and on the other side
of it, flip it over, the other
side naturally doesn't have any
color on it.
The Neandertals took a form of
iron oxide and painted on that
to mimic the other side.
In southern France we've got a
site that has these pigment
crayons.
They're pieces of manganese
dioxide, and I've got a slide of
them, and they look like little
nubbins, like my kids are done
with the sidewalk chalk and you
can't use it anymore.
That's what these are like.
And you can see on them there
are these little striations.
And looking at them
microscopically, the striations
that are there, it makes a real
black pigment, this manganese
dioxide, the striations aren't
consistent with being scratched
on a hard surface.
They were coloring something
that was soft.
>> What would that have been?
>> We imagine either their skin
or some sort of animal hides.
They're making clothing that's
colored.
They're the first fashionistas
maybe.
(laughter)
>> We might find some DNA
in common with them
and, say, Calvin Klein.
>> Don't let him
hear you say that.
(laughter)
>> What the implication,
of course, is that
then there is all kinds of
abstract thinking going on.
>> Yeah, exactly.
This has got to be the tip of
the iceberg of what they're
doing.
And when we look at what they
have to have been able to do to
survive given their technology,
modern human hunter gatherers,
to do the same thing, they'd be
talking to each other, they'd be
passing down stories, they'd
have social networks to help
spread the risk when the animals
were scarce.
They'd have all those
adaptations.
Neandertals, they're not here
anymore.
So we wonder is there some
element of the modern human
pattern that they lacked?
And whenever we find these
unique sort of artifacts that
show us that thing that we used
to think separates us from
Neandertals doesn't separate
anymore.
They were doing this sometimes.
It helps narrow down the
hypotheses that are left.
>> What are we down to?
>> I think, look at the mode
of transition that we've got.
When humans disperse out of
Africa, clearly most of the
genome of people who live
outside of Africa now, 95% to
98% of it comes from Africa in
the last hundred thousand years.
So there's a big event.
Neandertals, presumably when
humans initially come into
contact with them, they're
mixing.
And we've got the evidence of
that mixture in our genomes
today.
Something like 1%, 2%, maybe 4%
of our genomes outside of Africa
come from these Neandertals, but
most of their genes are gone.
So what is it that could account
for that pattern?
Their anatomy is gone.
The brow ridge, that kind of
stuff is very rare now or
absent.
So you start thinking what is it
about them that has persisted,
and what is it that made us
different from them when it
looks like we do so many similar
things?
I started thinking of things
like energetics, disease, maybe
there's some pathogen that has a
real different effect on these
populations.
We think about longevity.
Today humans, it's normal to
live to 60-70 years old, even in
hunter gatherers who live hard
lives today.
Neandertals did not live to be
that old.
>> Did Homo sapiens?
>> Homo sapiens, by the time
they're dispersing out of Africa
into other parts of the world,
our modern hunter gatherer
pattern of longevity is in
place.
People are living to be old.
Of course today, look around the
population of westernized
countries, you see 80-year-olds,
100-year-olds.
That's not normal for hunter
gatherers.
It doesn't happen very often.
So there's continued change.
Most of that change recently is
cultural.
We wonder, for Neandertals and
later people, are there genetic
changes that are also helping to
push longevity higher?
Are there genetic changes that
make you better at talking or
give you some sort of advantage
in going beyond those large
animal resources and broadening
the resource base.
>> For a more stable existence.
>> Exactly.
It's real hard for us as
anthropologists to try to
reconstruct what life was like
before agriculture because even
hunter gatherers today, people
like the bushmen of South
Africa, are trading with
agriculturalists that live
nearby.
>> So you don't have a
hermetically sealed culture.
>> That's right.
And every where that's really
good hunter gatherer habitat was
taken up by agriculturalists
3,000 or 4,000 years ago.
So we can't look at people
living in rich resource bases.
The hunter gatherers we know of
live in real marginal habit.
The Neandertals had this weird
combination.
They lived in the best places
but with the worst technology.
>> So of that, what, 4% of our
genome that's Neandertal, what
is it?
>> What is it.
>> What do we get from it?
>> We don't know.
This is the exciting thing.
My lab right now, we're trying
to figure out what some of these
places are.
What do they do.
We know of genes that are
selected in recent human
populations because we've
compared humans to each other.
So we know that things like skin
color, they're different in
different populations, there are
genes that correspond to those
differences.
We're now looking to see do the
Neandertals have any of them.
It's a complication that most of
the things that are real
different between populations
today are real different
because they differ recently.
Skin pigmentation is an example.
We know of maybe a dozen genes
in Europeans that correlate with
lighter skin, and those dozen
genetic changes, so far the ones
that we know the age of are all
real recent, 10,000 or 20,000
years.
And this maybe really
post-agricultural selection
that's with lighter skin we're
talking about vitamin D.
So diet change makes a
difference.
>> So it wouldn't be related to
the retreat of the Ice Age and
the fact that Homo sapiens are
moving farther north into Europe
where they would need more
vitamin D absorption from their
skin.
>> It could easily be.
Now with Neandertals one of the
real interesting things we no
about their genome is that they
had red pigmentation for hair.
>> The Neandertals, they were
red heads.
>> They were red heads.
They were red heads because they
have a genetic mutation that we
today, humans don't have.
So this isn't something that we
got from them.
The human versions now are all
new.
So here's a change that,
why are people red heads?
Maybe it correlates with lighter
skin.
It seems to correlate a little
bit.
So this is may be the selection
for skin color.
Darwin thought that this was
about sexual selection.
Red heads are sexy.
>> A good 19th century aesthetic
that he was superimposing on
science.
>> So from his point of view
this was all about taste and
populations establish their own
taste.
>> Which is a very hard thing to
trace through a genome.
>> Right.
And it's something that wouldn't
work in the tropics where you
need to have dark pigmentation,
but in Europe you're sort of
free to vary.
The Neandertals had that.
It's not a stretch to think they
might have had other pigment
variations that would still
survive.
We haven't found them yet.
And it's that way with a lot of
things.
We don't know yet what the
Neandertal genes did that we
still have.
But we're looking.
And I think before the year is
out we're going to have some
good hypotheses about stuff that
we got that came from them that
does things.
>> So the Neandertal was not
really a different species from
Homo sapiens or they wouldn't
have been interfertile.
>> I think that's a main message
that is coming out of this.
It's sort of a misconception
that if you look at species in
nature they could never have
fertile offspring.
A lot of cases of good species
are good species because they
look different, they live in
different places, and yet if you
bring them together they with
reproduce.
And chimps and bonobos are like
this.
They live in different places.
They have very different
behaviors, especially social
behaviors.
But if they're housed together
in a zoo they can and do
reproduce and have fertile
offspring.
Humans and Neandertals, they're
not separated from each other as
long as chimps and bonobos are.
And they not only reproduce with
each other in captivity,
there was no captivity when they
reproduced, that was their
natural habitat.
So we would say biological
species concept, they're the
same species.
>> But we still don't know why
Homo sapiens had this runaway
success and Neandertals were,
let's say, got second best just
by dint of living on through
Homo sapiens.
>> It's completely open.
We can disprove some hypotheses
now, right?
For example, we know from the
genome of Neandertals now that
there's one gene that's real
unique in humans, different in
humans than other kinds of
mammals, it's called FOXP2, and
we think that this gene has
correlated with language ability
in the sense that it's real
strongly conserved, it
contributes to the development
of the language areas of the
brain, and in humans that have a
broken version of it, they have
trouble talking.
So put those things together and
say this might have changed in
humans because of the evolution
of language.
Neandertals have our version of
it.
Neandertals have a bone in their
throat called the hyoid bone, as
other mammals do, but theirs is
shaped like ours.
So it looks like their throat
could make the kinds of sounds
that ours makes.
People who lived before
Neandertals, if you look inside
their inner ears, or their
middle ears, excuse me, at the
tiny bones that transmit sound,
they're shaped like ours and not
like chimpanzees.
So it looks like they were
hearing the kinds of things that
we hear.
So you put these things together
and it looks like Neandertals
probably talked.
But did they talk in precisely
the same way that modern humans
do?
That's an unanswerable question
for us now.
So we sort of whittle away the
wrong ideas.
We said, they're stupid, they
couldn't talk to each other,
they obviously couldn't adapt as
well as humans could.
We can disprove part of that.
And that opens up new
investigation.
Can we establish what kinds of
things are possible given what
we know about their genetics.
That will be the next 20 years
of research.
>> How could you ever determine
what they talked about as
opposed to Homo sapiens.
It makes sense from an
evolutionary standpoint or a
natural selection standpoint
that if Homo sapiens could, say,
express abstract thought better
that they would gain the upper
hand.
Certainly if you had a plan, any
kind of operation, whether it's
a hunting operation, a military
operation, you will have the
upper hand.
But how can we ever determine
that that was the kind of
difference in the way
Neandertals talked versus Homo
sapiens?
>> You know, some day we will
know I think.
We'll never have the full
answers.
It's not like we can put an
anthropologist there and watch
them.
But the way that we can unravel
genetic differences between
people now, we're discovering
health risks of all kinds that
are based on very subtle genetic
changes and yet have sort of
effects on you at given stages
of your life, we're going to
discover things about
Neandertals that are different
from us.
We can take Neandertal genes and
put them into mice and see what
their effects are in vivo.
That doesn't mean that we can
tell the difference between them
and a human that way, but the
first thing they're doing with
this red hair version, it's
inferred to be red hair because
of computer predictions.
Here's what the structure of the
molecule is and here's how it
would have received the hormone
that makes them make black
pigment and that would have
compromised it.
But the next obvious thing to do
is put it in a mouse and see if
they turn out red.
So actually we have some really
interesting ways of developing
more and more knowledge about
this, and we'll never get to the
end.
But this isn't like it was even
when I started where you looked
at two skulls and said I think
they're different and I can
count the differences and that
must mean X.
I mean, we can really test a lot
of these hypotheses now and it's
become a science of the genome
age.
>> How do you suppose
Neandertals decided to leave
Africa so much longer before
Homo sapiens got around to it?
What would be the difference in
the two populations that would
account for that?
>> With hunter gatherers this is
always about where is it easy to
live and how many people are
already living there.
Hunter gatherers really don't
tolerate over population in one
place.
And so you get to a certain
point and people don't tolerate
each other anymore.
It's like, I'm fighting with
you, I don't have to live here
anymore.
I can walk down to the next
place, if there's nobody there
already.
So dispersal in human
populations can happen just with
lightning speed if we look at
the archaeological record.
We think the spread of humans
from the initial people reaching
the new world, which was in sort
of Beringia, the northern Alaska
connection are Siberia.
The dispersal from there to the
southern end of South America
may have taken as little as a
thousand years.
>> That would have been
spectacular.
That's certainly a revision,
isn't it?
>> But if you think about how
little it takes in terms of
growth to start to spread a
population in numbers, if you
grow at 1% or 2% per year, you
very quickly fill up the world
because our population today is
growing 2% per year.
It doesn't take very long to
ramp your population way up.
Now with hunter gatherers,
before there was agriculture,
they're resource-limited.
They're like any other species
on the planet.
If there's too many of them,
there's not enough food or
there's too much disease or they
fight with each other too much.
And in any event, it's
resource-limited.
So what happens is Africa is
probably always more densely
populated than anywhere else
because that's where humans
originated.
And in the Middle Pleistocene
400,000 years ago, Africa is the
densest place in the world just
as it was 20,000 years ago.
Well, dense for hunter gatherers
is not like dense for
agriculturalists.
But it's uncomfortable.
So if there's somewhere for you
to move on that you discover is
a nicer place to live, you move
there.
If it really is a nicer place to
live, then your population
grows.
It doesn't take very long to
fill up a new continent.
>> Significance that it was the
Neandertals who left town
though?
>> You know, I think, my guess
would be that they happen to be
living in the northeastern part
of Africa at the right time, and
they were obviously people who
spread from Africa just as soon
as their legs were long enough
and their hunting was flexible
enough to do it.
That seems to have happened
almost 2 million years ago.
After that I imagine that there
were wave upon wave of new
things happening in Africa,
people competing with each
other, developing new methods of
life.
They get better at it.
If they're the northeastern
corner of Africa and they've got
a new trick, they can spread
outside of Africa.
And probably those populations
are constantly mixing, coming
into contact.
And the most recent version of
this, the out of Africa movement
of the last 50,000 years, in
some senses it was maybe the
biggest.
We know that it had a huge
genetic impact on the rest of
the world's population.
We trace our ancestry outside of
Africa today, 95% back to those
people who lived there
50,000-60,000 years ago.
>> Now if we think back to the
map that we saw a while ago of
the Neandertal occupation of
Europe, what would have kept
them from migrating further if
there was a problem?
Do we have a sense that Europe
was getting too crowded for
Neandertals and that's what
happened to them?
>> It's sort of interesting that
we have now one genetic hint of
the people who were around who
weren't Neandertals.
There were other people who
lived further east in China.
In south Asia, a big population
of ancient people.
We don't have a lot of skeletal
remains from India, from the
south Asian population.
We've got some from China, we've
got some from Java.
There's one bone, a little pinky
bone from a cave in the Altai
Mountains that has produced a
mitochondrial DNA sequence
really divergent from ours, it's
really divergent from
Neandertals.
So these other populations were
there.
They were in contact with each
other.
In contact, what I mean is they
were living in places that were
next to each other.
And the Neandertals, they were
real successful where they lived
but they couldn't just go
anywhere.
>> And they were already hemmed
in 80,000 years ago.
>> Exactly right.
They couldn't go north because
they couldn't live farther
north.
The glaciated habitat was not
where you want to be hunting big
animals with no cover.
We think probably, and based on
the signature of sites from the
early modern humans, they look
like they came not only from the
east into Europe but also from
the north.
The last Neandertals, they're
hanging on in Spain.
So these are people who were
being pressured when they
finally did succumb to this
growing modern population.
They were mixing as they went,
possibly.
But it's that move of modern
humans taking advantage of new
resources maybe that the
Neandertals couldn't that really
made the difference in the end.
>> We don't have any evidence of
genocide?
>> We don't have any smoking
guns.
There's one Neandertal from
Shanidar, from this site in
Iraq, that has a wound in a rib,
two adjacent ribs actually, and
it's from the fact that there's
the notch in one rib and the
notch in the other rib that we
know this was a small point.
Neandertals didn't use small
points.
We never found a small point
with a Neandertal.
So if you think, well who was it
that was hitting this guy with a
small point, which is an atlatl
or maybe even a bow, it could be
a modern human.
So the story that goes along
with this is that modern humans
were killing the Neandertals.
Maybe, maybe so.
But I imagine this is something
like anytime we see populations
come into contact from different
parts of the world with
different technologies.
Think of the new world after
Columbus.
Think of Australia after Captain
Cook.
Anywhere that you see these
populations come into contact,
there's a lot of dying of one of
them and usually a growth of the
other.
And the Neandertals may have
been one of the first examples
of this.
>> Not just a conflict but also
a coming together.
>> Absolutely, yeah.
>> John Hawks, thanks for
joining us for University Place
today.
>> Well thank you very much.
>> I'm Norman Gilliland.
I hope you can be with me for
the next issue of University
Place.


 

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