(upbeat music) – [Voiceover] Have you
ever wondered about your human ancestors
that lived more than one million years ago? You may have images
of ape-like people that sheltered in
caves and used clubs. A special group of scientists,
called paleoanthropologists, use clues from the
prehistoric record to uncover the mysteries of what early
humans were really like. The work of these scientists
helps us understand what it means to be
human and how we evolved to the unique species
that we are today. In this episode, we’ll
meet paleoanthropologist Briana Pobiner to learn
more about early human life by looking at what was on the
menu one million years ago. – Hi, thanks for joining us. I’m Maggy Benson, host of
Smithsonian Science How. We have a really awesome
show planned for you today, but before we get started I
want to ask you a question. You can respond using
the poll that appears to the right of
your video screen. What makes humans different
from other animal species? Is it talking, walking
upright, using tools, thinking abstractly,
or having big brains? Take a moment to think about it and put your answer in
the window that appears to the right of
your video screen. (upbeat music) All right, it looks like the
answers are still coming in, so before we go to the
results, I want to introduce our special guest today. Today we have with us
paleoanthropologist from Smithsonian’s National
Museum of Natural History, Dr. Briana Pobiner. Thank you so much for being
here with us today, Briana. – You’re welcome. – Right now, we basically
have three answers coming in that are top, walking
upright, thinking abstractly, and using tools are all
answers that people are responding that
make humans unique. What do you think about that? – I think in some ways all
of those answers are correct, but really it’s sort
of an all of the above. It’s the whole package that
makes us uniquely human. We have these amazingly
large brains, we have very sophisticated language and
technology, and we walk upright on two legs which is
fairly unique among animals. – [Maggy] I have to ask
you, what about chimpanzees? I know that we’re really
similar to them in all of our behavior, so does that
make us really that unique? – We’re not only similar to
chimpanzees in our behavior, but the way that we look
and also our genetics. We are 98.8% genetically
similar to chimpanzees. They do a lot of the things
that we do, they walk upright from time to time, they
use tools, they have fairly sophisticated communication,
but actually humans and chimpanzees share
a common ancestor that lived about six or
seven million years ago. So we’ve had quite a long time to evolve on those
separate paths. If we have 3.2 billion
base pairs in our genome, a 1.2% difference is maybe
35 million differences. – [Maggy] Oh my God, so only
1.2% of our genetic code is different, but it really
makes us uniquely human. – It does, that
makes us who we are. – I guess 6.7 million
years of evolution too. – That’s right, that’s
quite a long time. – Can you tell us what
a paleoanthropologist is and what you do to
study human evolution? – Sure. A paleoanthropologist
is essentially a scientist who’s interested in early
humans, what they did, how they lived, what they
ate, all about their biology and behavior. So
paleoanthropologists usually use three lines of evidence to
look at early human lifestyles. We use the fossils of the
early humans themselves. We use animals’ bones or
fossils of animals that lived at the same time as
those early humans. We can tell something
about environments from those animals, possibly
something about diet. We can also use the
archaeological record. Stone tools, pottery, any
kind of, basically anything that was left behind
that early humans made. – Interesting, it sounds like
there are a lot of different puzzle pieces across those
three lines of evidence. – There are and it’s
really neat to try to fit those puzzle pieces together. We’re never gonna have
every single piece, but really trying to make
sense of the evidence that we have. – Can you show us something,
I see evidence on the table here, can you show us
something that you brought? – Sure, I brought the exact
replica of a skull of probably my favorite species on human
family tree, Homo erectus. One of the things that makes
Homo erectus so special is that it started to incorporate a
lot more meat into its diet. I’m really interested in meat
eating and early human diets. By about 1.8, 1.9 million
years ago, when this species evolved, it started to eat
more meat and more marrow and other things
from large animals. We can see that reflected
in the shape of its skull. In comparison to a species like
Australopithecus afarensis, which lived much earlier
back to almost 3.9 million years ago, the slope of
the face is much different. A lot of the face
of Australopithecus used for chewing, but
then once early humans started using stone tools
to butcher meat they could basically process food
outside of their mouths. So our teeth got smaller,
but our brains got bigger. – Interesting. So what
did we eat before we started eating meat? So what did maybe afarensis eat? – Even back to the
earliest human ancestors, back to six or seven million
years ago, we probably had a very omnivorous diet,
so eating plants and animals. Eating things like fruit and
leaves and berries and probably small animals, maybe insects,
lizards, eggs, all sorts of things, kind of anything
we could get our hands on. – You mention that there
were other species, other than afarensis
and Homo erectus. How many human
species were there? – The family tree, our family
tree is pretty bushy actually. It’s very diverse, there
were maybe somewhere between 18 and 20 species
on our family tree. At any one time, there were
often several species living at the same time. It’s fairly unique
to be a modern human and to be the only
species left standing. You can see right there, kind
of on the top of the tree. – [Maggy] Did all of these
animals live at the same time? – [Briana] Many of them
did, you can see where some of them overlap and
in fact, modern humans, our time span overlaps with
at least three different other early human species. – [Maggy] Interesting,
so the early humans that you study,
where did they live? – There are a couple
places that I work. One site that I am
currently doing research at is called Olorgesailie, it’s
a site in Southern Kenya, in the Southern
Kenya Rift Valley. We actually have a beautiful
photo of Olorgesailie right in back of us, this is
what the landscape looks like. It’s very eroded but I
think it’s quite beautiful. We’re working at Olorgesailie
under the direction of Dr. Rick Potts, who’s also
a paleoanthropologist here at the Natural History Museum. – [Maggy] What kind of
things do you look at at Olorgesailie? – [Briana] I’m particularly
interested in looking at the animal bones there. I’ve actually brought
one with me today. This is a rib of some
sort of large animal, maybe about a zebra
size, that’s about a million years old. – [Maggy] Wow, that’s
so interesting. So you may find some
of these fossil bones here at your field
site in Olorgesailie. What else do you find
at the field site here? – We find lots of different
types of evidence. It really takes a team to
be able to put together the pieces of this
prehistoric puzzle. We have archaeologists
who study the stone tools. We have paleoanthropologists
or physical anthropologists who study the actual
fossils of early humans. We have paleontologists that
study the animal bone fossils. But geologists are also
key, so these are scientists that help us figure
out how old the fossils and artifacts were and
also help us reconstruct the types of landscapes
and environments that early humans lived in. – Wow, that’s
really interesting. We already have a
student question for you. Are you ready to take it? – Sure. – This one comes
from Amy from Acacia. She wants to know who
is our closest relative? – Who’s our closest relative?
That’s a good question. That’s sort of a
million dollar question. Right now, based on
available evidence, we think that probably our direct
ancestor is a species called Homo heidelbergensis. This species lived in
Africa and in Asia, I’m sorry and in Europe, that dating back to
about 800,000 years ago. Populations of this species
in Africa evolved eventually into our species, modern
humans or Homo sapiens, about 200,000 years ago. The populations in Europe
evolved into Neanderthals and Neanderthals are our
closest extinct relatives. – [Maggy] Wow, interesting. We have another
question for you. This one comes from Ruth. Ruth wants to know is
there any way to know what we will evolve into? – Wow, that’s a
fascinating question. A lot of that’s hard to predict. The way that evolution
works is that changes often happen or are
selected for in response to a particular selective
pressure in response to a particular
environment or challenge. Not knowing what those
challenges will be in the future, it’s a little
hard to predict how our evolutionary trajectory
is going to proceed. – Great. I want to get back
to this bone that you brought. That was recovered
from Olorgesailie one You said that looking at
marks on bones is your primary research, what do you look
at when you look at marks? – I’m particularly interested
in trying to figure out who made these marks on bones. Some of these marks were
made by early humans when they used sharp stone
tools to butcher animals. Some of these marks
were made by carnivores when they were basically
eating their prey and munching on these bones. – [Maggy] So, like we
see on the screen here, are those chew marks or what? – [Briana] Those are great
examples of cut marks on fossil bones, cut marks are
linear, they’re very narrow. They usually have a
v-shape at the bottom and they’re usually either
oriented right across the bone or kind of diagonally
across the bone. In contrast, carnivore tooth
marks, especially tooth pits, they’re usually round,
they’re crushed on the bottom of the surface of the mark,
and they can sometimes be scattered throughout
the bone or often sometimes kind of concentrated on places
where carnivores have chewed. – [Maggy] I want to know how
you actually do the research to be able to understand what
made that mark on the bone, because we don’t have a
looking glass to look back a million years ago. – I would love that. One thing I do is I’m trying
to determine what different carnivore chewing
patterns look like. To do that research, I work
at another site in Kenya, called Ol Pejeta
Conservancy which is a site in central Kenya, it’s
a modern game reserve. I’m working there together
with my colleague, Dr. Fire Kovarovic from
Durham University in the UK. We are basically looking at
kills that lions, leopards, hyenas, different
carnivores have made to try to determine if we can
figure out what that lion chewing pattern, that leopard
chewing pattern looks like. So we go out in these
modern landscapes, we follow these carnivores around
and then we pick up their leftovers and study those bones. – Is that scary? You’re out on this
modern game reserve with these big carnivores. – Not only with these
big carnivores, these big meat eaters, but elephants
and rhinos and buffalo. It can be a little scary,
but we always go out with an armed guard, with an
armed ranger, any time we’re out of the car to
make sure that we’re safe. – Interesting, did you
bring any objects here today that show what some
of these chew marks look like on the bones? – I did. Here is one
example of a zebra bone that has some nice chewing
damage from a lion. You can see right here
where the arrow is, there’s basically a big
carnivore tooth mark back here and over here is all of this
nibbling damage that happened when a lion was chewing to
try to get this meat off and ended up chewing
part of the bone. – You’ve done a great job
helping us understand what a chew mark looks like and
a bite mark and a cut mark. Let’s go back to this rib
bone that you brought. – Sure. – I think maybe we should
ask the students what they think that these
marks were made from. – [Briana] That sounds great. – [Maggy] Wonderful, students
take a look at this bone and maybe Briana’ll point out
what marks we’re looking at. What do you think the marks
on the bone were from? Grass impressions, tooth marks, water staining,
or butchery marks? (upbeat music) All right, Briana, the
answers are coming in and 50% of our students think
that they’re butchery marks. What do you think about that? – I think that’s a great answer. Really it’s the fact
that they’re quite linear and straight and
narrow that gives away that those are butchery marks. – [Maggy] So they’re butchery
marks made by stone tools. That means that
early humans were using stone tools a
million years ago? – Actually early humans
were using stone tools all the way back to about
2.6 million years ago. We have very sort of simple
technology at that point, we basically have simple
rocks with flakes that were knocked off of those rocks. Not very sophisticated, but
they were really perfect at getting a sharp edge
to be able to slice meat off of bone. By the time Homo
erectus came around, there was a big innovation
in stone tool technology. This is a hand axe,
this is a real hand axe from Olorgesailie, this
hand axe has a very specific pattern that
these sharp flakes were taken off around the edge. It’s actually a very
efficient way to use your stone tool raw material. – Great. We have another
student question. This one comes from
Long Gone Daddy. Is there any evidence that
particular diet and nutirents contributed to brain or
language development? – That’s a good question. Actually there is a lot
of evidence, or at least a good hypothesis, that
eating meat contributed to an increase in brain size. So meat is a great resource
that has a lot of calories, it has a lot of fat and
nutrition, and being able to get all of that in a smaller
package versus a lot of leaves or fruit may have enabled
our brains to grow bigger. – Great, this one comes
from Briana from FIS. She wants to know where
do you take the fossils after you piece them together? – That’s a good question. All of the fossils stay
in the country where they’ve excavated from,
where they’ve been excavated. All of the fossils from
Olorgesailie stay at the National Museums of Kenya. They go to the Central
Museum in Nairobi. – Great. You mentioned
that these stone tools were used for butchery. Does that mean that they
were actually hunting with them too or were
they just using them to butcher the animals
and eat the meat after some animal may
have gotten to it? – That is another
million dollar question. We don’t have evidence
for hunting technology in the archaeological
record until about half a million years
ago. You’ll notice that’s two million years
after the evidence for this meat eating started. We think that sometimes
actually early humans were coming in after carnivores
were done with their kills or maybe even chasing
them off and that’s how they were getting meat
from these big animals. – [Maggy] Were the early
humans kind of waiting in the bushes, waiting for these
lions to get off their prey? – It’s hard to know, we
don’t have evidence for some of that specific
behavior, but we probably, we can infer from where
cut marks are on bones. If the early humans are
getting the really juicy parts of carcasses, it’s an
indication that they may have been chasing carnivores off
of kills or somehow being able to get better access to the
best parts of the animals. – Is that primitive
scavenging or is it actually an advance for that time
period to be able to be waiting and then
butchering these animals? – It’s funny, I think scavenging
gets a really bad rap. I think it’s actually a
fairly sophisticated behavior. You really have to know
your environment very well, know where the
carnivores tend to hunt, have advanced planning,
and very sophisticated communication and group
dynamics and social interaction. I think it’s actually a pretty
advanced kind of behavior. – Interesting. Eating meat
really was the critical changing point for us to be
able to have all of these human unique qualities. – At least it was a
very big changing point. There’s two other kind of big
shifts in early human diet. One is by about 800,000 years
ago, we have good evidence that humans were using
fire for cooking. Then by about 15,000 years
ago, it’s kind of late in the record as far as we’re
concerned, we have good evidence for agriculture
and domestication, which is basically growing
plants and tending animals for our own food resources. – Wonderful, you’ve done a
really great job at explaining to us what a paleoanthropologist
does, about your fieldwork here in Kenya,
here in Kenya, (laughs) and the evolution of
really our human diet. Let’s go to some
student questions. – Sounds good. – This one comes from Louisa. Louisa wants to know might
early humans have gotten the idea of cooking meat
from scavenging meat from animals caught in wildfires? – That’s a really good question. We think there were probably
occasional wildfires, that lightning strikes or
something ended up lighting these wildfires, it certainly
could have been from something like that,
that’s a good idea. – This question
comes from Haegen. Haegen wants to know
why were animals from millions of years ago so much
bigger than they are today? – That’s actually a
really good question. We have really across the
whole world and almost all of our continents, there
are big extinct animals that are no longer around today. I think it’s complicated,
but there’s probably a lot of reasons for that. – This one comes
from Harold Woods. Harold Woods wants to know
how many different types of food did we eat before
we started eating meat? – That’s a very good question. We have a lot of types of
food we were probably eating that don’t preserve, things
like fruit and leaves and berries, so we can
get preserved bones and sometimes even preserved
little bits of plants, but it’s harder to look
really deep back in the record and figure out what
we were eating. – This one comes from Scott
in Fairfax. Scott in Fairfax wants to know did early
humans eat raw meat? – I think the answer is yes. We have meat eating back
to about 2.6 million years ago at least, but we don’t
have good evidence for cooking until 800,000 years ago. It’s possible that we’ll
find earlier evidence for cooking, but it looks like
raw meat was being eaten for a long time. – Otto from Rapid City
wants to know what education do you need to do
this kind of work? – The first thing you
need is a college degree, usually in anthropology
but maybe in biology or geology or even something
like chemistry and physics to do some of those
dating techniques. Then most people do go
on and get a Master’s and a Ph.D. – Briana, what made you
interested in paleoanthropology? – [Briana] I admit that I was
not as interested in science when I was in high
school than I am now. It was really a class that I
took in college with a really inspiring professor that
got me started on the anthropology path and then
I went to a field school in South Africa and
absolutely fell in love with the discovery and thinking
about human prehistory and trying to find those
pieces to that puzzle. – Great. We have
another question. This one comes from
Jaclyn. She wants to know do you ever find painting on
any of the bones that you find? – Interestingly, we do.
Sometimes we find coloring. So pigments, either red
pigments made of ochre or black pigments like
manganese, occasionally we do find staining on those bones. – Wow, and you think that is
then two lines of evidence together as one, both the human
artifact and a fossil bone. – Exactly, it’s a little bit
later in time so we really don’t have the evidence for
making art until a couple hundred thousand years
ago, but we certainly do find marks on stones and
bones and certainly caves and things like that. – Great, Alex has a question. Alex wants to know did our
bones get bigger over time? – So our brains got bigger
over time and that meant that our skulls had to
get bigger over time, at least that part of our skull. In general, our body size
did increase over time, so our bones, our whole
skeletons, got gradually bigger over time. – [Maggy] And that was really
because of meat eating? – [Briana] It probably
played a big part, yeah. – That’s so interesting, I’m
looking here at the models that you have out on the
table, what order did they come in? Do you know? – Yeah, so I would actually
have to switch these two. The earlier fossils from
Australopithecus afarensis, leading into the earliest
members of our genus, the genus Homo, so you can
see a little bit of change in the size of the brain
and the slope of the face. Then once we get past Homo
erectus to Neanderthals, you can see they’re much
bigger and actually have a really large brain and
very big brow ridges. – Now Neanderthals, in
the geologic record, they’re kind of
recent, aren’t they? – They are and actually they
evolved around the same time that modern humans did,
about 200,000 years ago. – [Maggy] They were
found in North America? – They were found in
Europe and in Western Asia. – [Maggy] Oh, okay. – Actually, modern humans
when they migrated into Europe encountered Neanderthals, they
were living in the same place at the same time and we
actually know from genetics that they occasionally interbred,
they mated with each other. – Great, we have another
question from Patrick. Patrick wants to know how did
early man learn to make tools? – Oh, that’s a great question. I’m not sure we’ll ever
answer that question. It may have been initially
just picking up sharp stones and using those as stone
knives that gave the people the idea to actually
make early stone tools and to manufacture them
instead of to just kind of go out and collect them,
but we really don’t know. That’s a good question. – Wonderful. This
one comes from David. David wants to know when
did the early humans learn to build shelters? – So that’s a good question. We have the earliest evidence
for building shelters back to about 400,000 years
ago, at least that’s what we can discern in the
prehistoric record. – John B: what is your favorite
fossil that you’ve found? – Wow, that’s a hard
question because I love all the fossils
that I’ve found. Probably some of the fossils
that I’ve found where I’m digging up in
layers that are about one and a half million
years old and I can pick up bones like this cut marked
bone and I know that the last person that
touched this lived a million and a half years ago. Wasn’t quite like me, but
it’s really like reaching through the past and touching
evidence of behavior. – [Maggy] Sounds exhilarating. – [Briana] It’s amazing. – Brian wants to know since
the tools were made of stone, how hard were they to use? – Oh, that’s a good question. They actually weren’t that
hard to use in the sense that you could pick one up,
one that had a sharp edge, and it’s not hard to actually
slice meat off of those bones. Tools were also used for
pounding for probably processing plants. It was probably
hard to make them, but not as hard to use them. – This one comes from
Jonathan. He says besides the brain, did any
other organs change? – Well, interestingly, about
the same time that we see the brain size increasing,
we actually see the size of our guts and our whole
digestive tract decreasing. Those things might be
related, so our brains take up about 2% of our body
weight, but they take up 20% of our energy and our guts
take up a lot of energy. So potentially with eating
meat, we didn’t need guts as big so they got smaller
and brains got bigger. – Interesting. In a kind
of related question, Emma wants to know did
Salmonella or any other kind of diseases exist back
then that we have today? – It’s interesting. It’s
rare but we do have evidence of diseases, there’s actually
cancer or bone lesions on a Neanderthal rib from tens
of thousands of years ago. There’s actually a partial
skeleton from Northern Kenya where we know that this
woman suffered from hypervitaminosis A, probably
actually eating something that had a really high
concentration of vitamin A, which is especially
concentrated in liver and actually carnivore liver. – Wow, so you can really
actually see some of those diets in the fossil record, too. – And diseases
sometimes, exactly. – This one comes from
Lindsay. Lindsay wants to know how do you feel about
indigenous creation stories? – I think that basically
how we became human is a part of what it
means to be human, but I think that the
stories that we have in the cultural context
of how we became human are also a really important
part of who we are. – Great. This one is kind of
funny. Sophia wants to know will our pinky toe
evolve away? (laughs) – It’s funny, actually
having five fingers and toes is a really primitive
condition, in a sense. That goes back really far
in our evolutionary history. Unless there was really strong
selection for some reason for our pinky toes to go away,
they’re probably gonna stay put. – [Maggy] That’s
a good question. – It is a good question. – Raymond wants to know is
there any difference in early human bones becoming fossils
as opposed to animal bones? – The process was
probably the same. A lot of the bones, if you
find human and animal bones in the same layers, they
usually look the same. It’s really just the size
and shape of the bone that lets us know what
kind of animal or human they came from. – Going back to the size
and the shape of the bone, Anthony G. wants to know
how do you tell what kind of bone it is? Is there a spot
on the bone that tells you what kind of bone it is? – That’s a good question, I
actually spend a lot of my time trying to figure out what
bones these fossils are. Sometimes on parts of the
bones there are very specific shapes, you can see some of
these curves and ridges here. If you get chunks of bone
that have these shapes, they’re a lot
easier to diagnose. Sometimes when you have
really little pieces, it’s really hard to tell. – So you’re really kind of
like a forensic anthropologist, too, that we see on
crime shows like CSI? – In a way, trying to put,
look at tiny bits of bone and trying to figure
out what they are. – Thank you so much
for being here today and teaching us about
paleoanthropology, human evolution, and
early human diets. It’s been really enlightening. – [Briana] Oh,
well, thanks a lot. – Is there anywhere that
students can go to learn more about human evolution
and the work you do? – I would suggest
going to our website, which is humanorigins.si.edu. If you’re on social media,
you can follow us on Twitter @humanorigins and then you
can also find us on Facebook Smithsonian Human
Origins Program. – Thank you so much. – Thanks. – Thanks again for
joining us today. We’re glad that you came. If you missed part of this
broadcast or want to watch it again, it’ll be
archived at qrius.si.edu later tonight. Thanks for joining us
and see you next time on Smithsonian Science How. (upbeat music)