(piano music) – [Man] We are the paradoxical ape, bipedal, naked, large-brained, long the master of
fire, tools and language but still trying to understand ourselves. Aware that death is inevitable yet filled with optimism. We grow up slowly, we hand down knowledge, we empathize and deceive. We shape the future from our shared understanding of the past. CARTA brings together experts
from diverse disciplines to exchange insights on who we are and how we got here. An exploration made possible by the generosity of humans like you. (upbeat music) – Good afternoon, thank you
Bahani, you’re very kind. We all know fire today as a source of heat, light, protection. A technological aid and a social enabler. But it hasn’t always been like that. And at what stage did hominins
lose their fear of fire as something really dangerous? Wildfire must have been a source of fire for early hominins and presumably they grasped
it and used it right there at its source. But lightning is probably
the most common cause of wildfire in Africa and it thus provides a
seasonal source of fire. But a very brief source of fire. So in the early days, when
hominids first made use of fire it would not have been very commonly. We have to distinguish fire use as opposed to the deliberate control
of fire and its creation. So the opportunistic
seasonal collection of fire from a natural source seems
likely for the earliest hominins but what we don’t know is
whether in those early times, they could necessarily transport the fire, feed it once they got
it where they needed it and then maintain the fire
for as long as they needed it. As a sideline, it’s
quite interesting to note that Raymond Dart in 1948 named the three million year-old Makapan fossils Australopithecus Prometheus
and Job already mentioned that, but he named them that
after the mythological giant that had stolen fire from the heavens. And the reason that Dart named it that was because there were some
blackened bones associated with the fossils in the sites. And he thought that perhaps
they were making fire. But unfortunately, chemical
tests quickly showed that this was simply
staining on the burns, and so the name was discontinued until recently resurrected by Ron Clarke as the name for his
new fossil Little Foot. But of course not because Ron believes that those fossils were using fire, but because of the
morphological similarity. We have only rare evidence
for early fire use in Africa, and I’m selecting three of
the most famous of the sites to demonstrate that. Koobi Fora, Swartkrans and Wonderwek. So Koobi Fora is at Lake Turkana in Kenya. And it was excavated
predominantly by Jack Harris. The site is an open site
and I make that point because it’s important. It’s one and a half million years old, and Jack found burnt sediment
in the site associated with burnt stone and burnt bone. Many of the critics would have suggested that perhaps wildfire
swept through the site and burned the traces. But Jack points out that in addition to the burnt bone and stone, there are unburnt bones and
stones in between those patches. And so it seems most likely that hominids exploited fire here, though
perhaps very briefly. And at Swartkrans in Member 3 which is one million years old, Bob Brain found 270 pieces of burnt bone which he believes was evidence for fire, pretty much directly below
the grid that you see there and associated with those burnt bones were bones that had been used as tools. But subsequently Lucinda
Backwell believes were used for extracting termites
out of their mounds. Wonderwerk I think is
particularly interesting because this is a cave and I emphasize that caves are dangerous
places where carnivores live. And it would seem really
unlucky that hominids would be able to move in
there without the use of fire. And I emphasize always the difference between the use of fire as
opposed to the control of fire. There’s very little chance that
fire could have accidentally got into Wonderwerk because
the fire traces here are 30 meters from the entrance. And this implies that the hominins would have transported
fire from its source, perhaps wildfire but the
traces are ephemeral. So fire probably wasn’t
maintained for very long within the site. Here is the stratigraphic
evidence and micromorphology from Stratum 10, one million years old. And if you have a look
over on the left there, within the black box, you’ll
see the layers of ashes that demonstrate that fire. Alongside that also, there
were burnt bits of bone and FTIR, Fourier transform spectroscopy demonstrates that burning of bone. They were actually on hand axes
associated with Stratum 10. Now there were no fossil remains but presumably the actor was Homo erectus, also known sometimes in
Africa as Homo ergaster. Leaving aside those sites for the moment, we must ask a question, what evolutionary changes were
taking place from the time that we see the evidence for fire? And is there any way of linking
these changes to fire use? Homo-erectus appeared in Africa somewhere between two and one-and-a-half
million years ago. That’s certainly before we
see the archeological evidence for the traces of fire that I showed you. But what is interesting is that compared with earlier hominins, the brain size of Homo erectus increased and the teeth and the gut size decreased
as Job showed you earlier. Big brains are expensive tissues and this increased brain size
yet reduced tooth and gut size imply that Homo erectus must have had an enriched diet compared with earlier hominins. Now there are competing
schools of thought about why the physical evolution
took place at this time. The first one is that hominins may have become more
effective at obtaining meat, especially fatty meat. Secondly, that hominins may
have processed food mechanically in the case of plants to break down fiber, in the case of animal
foods to break down tissue. And thirdly, that hominins may have cooked their food sometimes. How likely is it that Homo erectus sometimes used fire for cooking? This claim is made in
“The Cooking Hypothesis” by Richard Wrangham in his
wonderful book “Catching Fire”. And cooking would especially
benefit the young or the aged with deficient teeth. But the sporadic archeological
evidence for fire use doesn’t wholly support
the cooking hypothesis. But as archeologists, we
recognize that evidence may be absent for several reasons not least preservation
in many of the sites. So could she have cooked
dinner some nights? And more importantly could Homo
erectus have roasted tubers like the Hadza do today? O’Connell and colleagues in
their Grandmothering Hypothesis suggests that there sort of being a particularly cogent thing
for older women to do, that they would have improved
the health and the well-being especially of children by collecting tubers and roasting them to break down net fiber. And what is the earliest
archeological evidence that we have for roasting starchy plants? It’s certainly a long
time after the presence of Homo erectus. Now the African Middle Stone Age began about 300,000 years ago and we don’t get direct
archeological evidence for tubers even then. But at Border Cave which
is now being reexcavated under the leadership of Lucinda Backwell, we see a middle Stone
Age archive that begins about 227,000 years ago and continues to about 43,000 years ago. A stunning site as you
can see from this image. And at Border Cave, we have discovered starchy
underground stems and combs that were roasted from at
least 160,000 years ago, perhaps 200,000 years ago. So in Members 5BS down at the bottom and Member 4WA, we have now
more than 60 whole corns or tubers that were roasted and preserved. After about 200,000 years ago, Homo sapiens in many parts of the world developed pyrotechnology even further. And this suggests that perhaps
fire was now created at will, that people had control of fire. Perhaps through percussion of rocks, the strike-a-light method
or friction of wood on wood. But African archeology
is silent on this matter. We simply don’t have evidence for that. And yet we see increasingly
sophisticated pyrotechnology appearing through time implying that fire should have been created
whenever it was desired. So I’ve chosen three South African sites just to demonstrate some of that rather complex pyrotechnology. Down in the South,
Pinnacle Point and Blombos. And up on the East Coast, Sibudu. Rocks were heat treated at
Pinnacle Point 164,000 years ago. And there at the bottom left
you see a heat treated biface from the area. The heat treating of rocks
improves their flakability, it makes it possible to
strike longer thinner flakes and it makes it easier
for the stone tool napper to strike those flakes. It also improves the
quality of the rock itself. And Blombos, the heat
treatment of silcrete about 75,000 years ago demonstrates that it facilitated the pressure flaking of points to produce these long thin rather beautiful points. At Sibudu, we see something different but it’s much more recent. By 72,000 years ago, people
were making compound adhesive. And Ramen and EDS spectra
show that both hematite and carbon was part of the recipes. And at 64,000 years ago, gas
and liquid chromatography confirmed that there was coniferous resin on some of the tools mixed
together with hematite. Now, adhesive needs low temperatures for the drying and the hardening. So fire is an important part of the complex adhesive
manufacturing process. And temperatures were controlled
through firewood selection and the knowledge of how
much wood should be used on any given fire. To sum up, the first use
of fire by Homo erectus were seasonally opportunistic. The creation at will by Homo sapiens, the creation of fire
at will by Homo sapiens probably started somewhere between 300,000 and 200,000 years ago
in the Middle Stone Age. And although we don’t have
direct archeological evidence for this, increasingly
sophisticated pyrotechnology from this time suggests that people must have controlled fire. Now in Europe we know that Neanderthals were using manganese oxides
and various rocks to create and strike fire but we haven’t yet found any of that evidence in Africa. I’m sure it’s simply a
question of looking for it and that that’s a story that
will be told in the future. In addition to the heat treatment of rocks and adhesive manufacture, people used fire to create medicinal smoke through the careful choice of fire woods. They used campsite
maintenance by using fire to clean up their bedding for example and clean trash from these sites, which undoubtedly would
have improved the health of the people who lived there. They used fire for
hardening of wooden tools, and Hillary Deacon thought
that they might have stimulated the growth of fresh grass in the felt even during the Middle Stone
Age to lure game to sites. These and other hot topics are fuel for another day so thank you. (audience applauds) – Good afternoon, it’s an honor
and a privilege to be here, thank you very much. So I will talk about Klasies
River main site today. So Klasies River main site is situated in South Africa on the
southern Cape coast. And what you see there
is that it’s situated close to quite a few very well-known caves from which we know quite a lot about especially the evolution of modern humans. On the picture below you can see there’s a picture of Klasies River
and there you can see that it’s right on the coast,
so it’s very picturesque to work there, a very nice environment. Also on that bottom slot you can see that there is a lot of
lush vegetation around it. It consists of forests,
a (mumbles) and thicket. That is enough to see to
all of your plant needs if you had to rely on that for food. So this picture shows you
Klasies River main site and what you may first
see is that it consists of four recesses or caves, that we call by different names. So there with cave 1A, I’ve put
you two little human figures to show you the scale. This is against all of
these cave 21 meters of shell midden deposits formed. And this means it’s one of the largest shell middens in Africa dating to between 120 and 48,000 years ago. Then there was a break in occupation and then after some
erosion of the deposits, later Stone Age or Holocene
people came in again and occupied the site from
4,800 to 2,300 years ago. So this vast amount of
shell midden deposits is one of the best features of the site but it’s also one of the most challenging. Because if you have only one
career, where do you start? So there’s a lot of work to do. So what I want to talk to you about today, being such a large deposit
is just flashes of light on some of the aspects
on which Klasies River can throw some light. So at Klasies River, we
have quite a few hominin or hominid human representatives. I will talk about some evidence that highlight the ecological genius and cultural flexibility and complexity of our early ancestors. And I would like to emphasize
that they achieved this without our current super culture, so they really adapted
to that environment. So who lived at Klasies River? We’ve got more than 50 human
fossils at Klasies River and most of them they, between 120,000 and 90,000 years ago. What we can see from
the remains that we have and in the previous slide you will see that they were quite broken up, small pieces of human remains
so we don’t have a full skull or a complete skeletons
fragmentary remains. But what we can still say from that it’s that it’s a morphologically
variable population with very small individuals as well as larger robust individuals. Interestingly, for Klasies River, we get mostly adults represented. For most of the other (mumbles) sites we find mostly infants
represented, so that is perplexing why is this the case? We do have only three teeth of infants, and in the picture that you see there. that’s the Howiesons Poort deposits dating to around between 70 and 50,000 years ago. So if you find teeth of
infants in a deposit, you have to think that it
was families that lived here. These Howiesons Poort
deposits are the deposits that we can see the highest
density of occupation in this site so that’s quite interesting that we find the infants in this layer. Something that’s really
interesting for Klasies River is that almost all of the human remains, especially the lower deposits, those between 120 and
90,000 years ago are burned as you can probably see from this picture and many of them have cut marks. So what is the logical conclusion, is that it was probably
cannibalism that was practiced. Was it ritual cannibalism? Was it dietary cannibalism? We do not know, it is one of
those issues that we need to, that we hope to throw light on in future. If you look at the
remains on Klasies River and that these are
mostly the food remains, you can see that the deposits
from the lower most layers, 120,000-year layers consist
of dense shell middens with all the foods that went into that, so it’s foods from the
coastal environment, fauna, fireplaces, et cetera. So from this you can see
that in this time range that they followed from 120,000
years to 48,000 years ago, we know that the climates fluctuated. And in that time period they targeted different kinds of foods. Klasies River is often facetiously called the earliest seafood
restaurant in the world because at the site we do find as I said in the lowest layers, these dense shell middens. And this is one of the
earliest occurrences of this very dense shell middens. So here you see a few
of these food remains that we find very often there, still remains a shellfish and fish. This is combined then with
large fauna and small fauna. So I’ve put this very large, we call this above it class
size, size class five. It’s above 900 kilograms,
very large (mumbles). And to be able to hunt
such above it successfully you have to cooperate. So we can see throughout the sequence that they were very successful, intelligent, cooperative hunters. That not only targeted the bigger animals but also very small animals. Interestingly since
I’ve started excavating at this site again of around 2015, the layers that we’re targeting now are about 110,000 years old. And what we observed in these layers are these red and quartzite blocks that we haven’t seen before. These blocks are associated
with leached ashes and food remains. In this picture you see postdoc, she was my postdoc, Sonia Benson who did a lot of experiments on quartzite and how it behaves if it
comes into contact with fire. And what we did determine
then is that probably these quartzite blocks
were used to roast food on, and that’s a very early occurrence
of that kind of behavior. Also at Klasies River
you find many hearths. So what you see here on
this side is cave one where we’re currently excavating. So this is what we call the wetness bulk and these layers go from
about 120,000 to about 90,000. This is the picture
higher up in the sequence where we have the
Howiesons Poort deposits. So you will notice here
the lowermost deposits here are full of hearths, it’s these ashy lines as well as these deposits
here full of hearths. So what has been done
here in collaboration with Susan Mentzer and Cynthia Larbey is to take samples from these hearths. Cynthia Larbey took samples of
the ashy parts of the hearths and the darkened soils under that and it’s scanning
electron microscopy on it. And what she did find in these
slides or in these remains was the remains of starchy tissue of underground storage organs in the ashes of the 120,000-year-old hearths as well as the 60,000-year-old hearths. Susan Mentzer, she did
micromorphology and she also, she also identified
these parenchymous tissue in the sediments next to the ashes that Cynthia has identified. So this is pretty important. So so far it’s the earliest
direct published evidence. We also have very early
evidence from Border Cave for the deliberate
inclusion of starch in diet. We don’t think this is
the earliest evidence for starch inclusion because
the genetic evidence shows that modern humans have
more copies of the gene that produces salivary amylase. That’s the enzyme that breaks down starch and this change seemed to have occurred already 300,000 years ago. So it seems that starch
was an important part of hunter-gatherer diets long
before agriculture developed. So this puts a new
perspective on to the idea that paleo diets consist
just of proteins and fats. So starch was really an important
part of that diet as well. So from this evidence that I
just really discussed with you very superficially we can say that humans at Klasies River followed a balanced diet with starchy cooked foods
and roots and tubers combined with roasted protein
and fat from shellfish, fish small and large fauna. So this complexity and ingenuity
that we see in the diets, we can also link that to
their cultural behavior. So here is a picture of
the stone tools found throughout the Klasies River sequence. So I’ve only put the typical stone tools from between 120 and about
70, 65,000 years ago. But what is interesting that we see just as the humans adapted
their diet through time, they also adapted the way in
which they made stone tools. And it was probably used
for the same kinds of tasks but they used different ways
to manufacture those tools. So this gives us some
inclination of how they thought. We do get clearer snapshots
of cultural complexity during periods of more
intensive occupation, and we think at the site it’s
around 100,000 years ago. For example, Blombos
Cave, 65,000 years ago with Howiesons Poort and 4,800 years ago. So time only allows me
to really quickly focus on some of these aspects. And I’ll do that in relation
to pigments and to bone tools. Because we seem to find
more of these materials during these time periods. So in the 100,000-year-old
levels, we do see this pigment that’s been shaped, or
ochre shaped in a crayon and you can see that it
has these lines on it so it’s been used and
shaped intentionally. Then there’s also this
piece of ochre which has been scorched or engraved, we
don’t think it’s a pattern. We just see, it was
probably used to make powder and this occurs in relation to, in association with these not bone tools made on the ribs of a very
large animal like an eland. And here you can see
some of these notches. We don’t know what it was used for, it is still a mystery but
we are working on that. And then in the 65,000-year-old layers, so we’re jumping up in the
sequence about 12 meters. We do find similar pigments
in the Howiesons Poort but I’ve mentioned earlier that we think it’s one of the highest
occupation parts of the sequence. Here we also find more ochre and here we can see that they
prefer the color red, ochre. They heated some of the ochre,
they also used yellow ochre and interestingly they made
a white material pigment from different materials that
might have contained both. So that’s a quite interesting phenomenon. Also in the Howiesons
Poort, we get bone tools like this bone point. This looks exactly like the
later Stone Age and Holocene and recent Bushmen burn points used in bone and arrow technology and an engraved piece of bone. Then I’m jumping up to
the top of the sequence, the later Stone Age layers, the Holocene layers
dating to between 4,800 and 2300 years ago. So these deposits, we
are very lucky to have it in the same site as the
Middle Stone Age deposits because it gives us a sharper,
much more detailed resolution impression of life ways and behavior. What we do find surprising is that we don’t find a big jump in complexity. The archeological materials, they’re basically the
same types of materials. But what this allowed us is to investigate often neglected part of
our archeological record, sound and our cue music. And in doing this we’ve done
a lot of experimentation and ethnographic research
to try and bring sound back into the Klasies River Cave 1. So this enigmatic implement was found by Singer and Wymer already in 1967 next to lower jaw of a human. It’s a dual hold, two-hold
instrument or implement dating to around 4,800 years ago. So here you see some of the
students doing excavations in that midden, Later Stone Age midden that is on top of the wetness bulk. It’s more or less these layers. And what we found when we looked
at the ethnographic record and by doing some experimentation is that as Singer and Wymer and
others have suggested that this might have
been a musical instrument or an instrument to make sound with. So I don’t know if you
know what a woer woer is or a wirrawirra, it’s just
the sound that it makes. So you put it in the middle
like Joshua is doing here. So we estimated the
length of the rope used by the ethnographic examples. And if you do this it makes a sound. And interesting, the sound is very similar to that made by bees. So we’re investigating this further. So this Klasies River’s archive highlights the kinds of achievements
of African populations that played a prominent role
in the development of humankind of people like us. I would like to thank
everybody for being here and for giving me the
opportunity to speak to you. Thank you. (audience applauds) – So I’m going to talk about behavior and settlement patterns in
Coastal Stone-age communities, the evidence from stable isotopes. And I’m talking about
this because if we look at the long history of our species, we talk quite a lot about
hunting and the role that hunting may have played in human evolution. We talk a bit about gathering plant foods and the importance of that. But we don’t talk very much at all about the importance of coastal resources. And there are interesting questions about when people first began
to use coastal resources, what the implications of this might be? And these questions are interesting because coastal marine areas like this are among the most
productive habitats on earth. And in more recent
times, habitats like this have been very important for hunting and gathering populations. Why have they been important? Well first of all,
coastlines provide abundant, reliable, nutrient-rich
foods like the shellfish. They also provide marine
mammals which are sometimes washed up on the shore. One doesn’t necessarily
even need to hunt them. You can collect beached animals. And when a large animal
like a whale is beached, that provides very large
quantities of food indeed. If coastal communities
have the right technology, they can catch fish. Coastlines provide a range
of stone raw materials and other kinds of raw
materials for making artifacts. Coastlines provide routes for dispersal. So one might expect that
the line leading to humans would have taken advantage
of coastal habitats from early on. I have to say that we don’t have much direct evidence of this,
but that’s at least partly because of issues to do with preservation. So over long timescales, coastlines shift, sea levels rise and fall. And so globally we’ve got
very little archeology of coastal areas that date
to the earlier periods of human evolution. In South Africa though we’re lucky because we’ve got a
relatively stable coastline, at least it’s remained stable over the last several
hundred thousand years. And so we have many
well-preserved coastal sites which make it a good place to investigate these kinds of questions. So in the latter part of the 20th century, most researchers thought
that aquatic resources only became important
relatively late in prehistory. Once populations had already grown and additional sources of food were needed to feed these extra mouths. But today rather different
perspectives are being offered, and some researchers are even suggesting that coastal adaptations
may have played a role in the emergence of our species, and that coastal adaptations may have promoted the
particular behavioral patterns that characterized humans. So what evidence do we actually have for early use of marine foods? Some of the earliest comes
from around the Mediterranean. We’re at the site of Terra
Amata in southern France. We’ve got shellfish that date
to about 300,000 years ago. At Benzu in North Africa, there are shells dating to
about 250,000 years ago. And at the Cave of Lazaret,
also in southern France slightly younger shells. At Terra Amata, these are associated with the shellian hand axes. But there are some disagreements
amongst archeologists as to the dating of some of these sites, as to what these shells
are actually doing there, are they really food remains? So we’re not entirely clear
what we’re actually looking at in these sites. I think there probably are food remains because we know that it’s not just humans that collect and eat marine foods. Non-human primates do it too. And this is a troop of baboons that lives very near Cape Town on the rocks collecting and eating mussels. This particular troop regularly
forages in the intertidal. And they simply pull off
the shellfish from the rocks and bite through them. Here are some more pictures
of them doing that. And this makes an important
contribution to particularly the protein component of their diet. But these baboons don’t do this very much. They spend less than 5% of their
foraging time on the rocks, and the rest of the time they’re
eating terrestrial plants and small animals and so on. Primates do this elsewhere
in the world too. We know that along the Somalian coast, yellow baboons forage for marine foods. In Southeast Asia crab-eating macaques eat intertidal organisms. So this kind of behavior
may we’ll go back a long way in the human lineage. And of course Neanderthals ate shellfish. We know that because they left the shells in caves in Gibraltar and other places on the Iberian Peninsula. So I said earlier that coastal
habitats were productive but we’re only just now
beginning to realize exactly how productive they are. These are some photographs that were taken as part of a research
project in South Africa where the researchers are
working with local communities who collect shellfish to feed themselves. These are relatively
impoverished rural communities and they collect shellfish
as part of their diet. And the researchers were
looking at how long it takes, how much effort it takes
to get a reasonable return in terms of the quantity of food gathered. And the results I think are astonishing. So on average, these
collectors can get almost 1500 kilocalories an hour
by collecting shellfish. And under optimal conditions, so optimal conditions are springload tide, when the seas are calm, they can collect 3400
kilocalories an hour. And if you think that
a sort of medium-sized, moderately active person needs about 2,000 kilocalories a day, this is very productive foraging. And it’s not hard, it’s
certainly a lot easier than trying to hunt down
and kill large game animals. So coastal food resources are rewarding, they are abundant, but they are spatially restricted. They’re restricted to the coast, the sort of linear edge
of the land masses. And so some researchers
are starting to explore the idea that perhaps foraging
in a landscape like this where the human groups would have been sort of aggregated
together might have perhaps promoted the high levels
of social interaction that are characteristic of our species. Here are some images of
the site of Pinnacle Point which is arid in the small
map on the bottom left there. Pinnacle Point has become
famous for the evidence that it preserves of marine
foods at 164,000 years ago. So the lower image here,
that kind of bank of material on the left is a consolidated deposit that has a lot of shells in it, it has a lot of stone artifacts in it and it’s cemented to the wall of the cave. It dates back to about 164,000 years ago. So we’re now back sort of
early-ish in the period of what some people call modern humans. The question is though,
what role did shellfish play in people’s diets at this time? So were the people who lived in this cave collecting shellfish just
occasionally like the baboons do? Or were they focusing
on these marine foods like more recent coastal
hunter-gatherer populations do? Here are a couple of sites
from the same part of the world that date to the last 12, perhaps even more recent than that, the last several thousand years. And you can see that those
are huge shell middens in the upper photograph. All of that gray area that you’re looking at on the ground there,
all of that is shell, that’s hundreds of thousands of shells. On the bottom image you can see very densely packed shell middens. And this is typical of the
kinds of sites that we see in more recent time periods. In older time periods, many of the sites don’t look as dense as this, don’t seem to preserve
this kind of evidence of intensive use of marine food. But it’s often unclear
whether that’s because people were doing something different
further back in the past, or perhaps whether the
evidence is just often not so well preserved. So in order to answer that question, in order to answer the
question of how intensively were people back a hundred
plus, thousand years ago focusing on marine foods, we might turn to a different way of investigating this question. And that is the kind of
thing that I do a lot of which is to measure the
stable isotopes in the bones and the teeth of consumers in order to try to assess what they were eating. So the way this works is
that we measure the ratios of carbon-13 to carbon-12,
nitrogen 15 to nitrogen 14 and those, the two isotopes in the pair, the heavier and the lighter isotope progress at slightly different rates through the reactions that
make up the global carbon and nitrogen cycles. And that happens somewhat
differently on land and in the sea. So we can measure these
isotope ratios in the bones of consumers including humans, and assist more-or-less whether
they were heavily dependent on marine foods or heavily
dependent on terrestrial foods. And these pictures were taken
in our lab in Cape Town. So we’ve done a lot of work like this on more recent coastal populations, because we’ve got a lot more
evidence from more recent times and it makes sense I think to use that more recent evidence that we can interrogate more
closely and then try to see whether we can reflect back
on earlier time periods. So here are the results of
some work that’s been done on coastal communities dating to the last few thousand years. And we have skeletons of
people who died and were buried in the area marked by the yellow ellipse. They have somewhat unusual bone chemistry indicating very intensive use of high trophic level marine foods. Their bone chemistry is
different from the bone chemistry of the people who died and
were buried at the sites marked by the yellow star
although that yellow star is only about 14 kilometers away. The bone chemistry is
sufficiently different that we can infer that there
was a territorial boundary between the two. Those two groups were separate, because we see different chemical
signatures in their bones reflecting diet over many years, probably several decades of their lives. Similarly, on the right,
people who died and were buried in caves marked by the inland green star, the uppermost green star
had a different diet. They ate very little seafood
whereas people who died and were buried on the coast marked by the lower green star were
eating a lot of seafood. So there was another territorial boundary between those sites. Over very small areas of ground. In the middle, we haven’t
got so much evidence so that’s why there’s
a question mark there? We can do even better than this. We can look at diet through life by comparing teeth and bones. So teeth form in childhood
and record the diet that the person was eating as a child, whereas burns continue to resorb
and reform throughout life so they give a longer term average. And by comparing teeth that
form relatively early in life like the first incisor and
the first molars shown here, those teeth complete their
formation pre-puberty. So we can look at a
childhood diet and compare it with an adult diet and we can tell whether people were living
as children in the same area where they died and were buried as adults. In other words we can tell whether people were bringing marriage partners in from outside their own territory or whether they were
getting marriage partners from within their own group. And in this case, the people
with the unusual bone chemistry in the yellow ellipse
were marrying partners from within their own group. So what we’ve got here
in recent time periods are societies that were living out very specialized coastal adaptations. They were specializing in
collecting marine foods and they had a social and a
kind of group organization that supported that way of life. And this kind of intense
coastal specialization is of course documented in many other coastal
hunter-gatherer societies elsewhere in the world, here in
California amongst other places, in other parts of North America,
in Europe and elsewhere. So one of the things we’d like to know is how far back in time does this go? How early in human development can we see this kind of intensive
use of coastal resources and what might that tell us about the way that coastal resources may or may not have factored
into human development. So we’re only just starting to do this but we now have some
results from Klasies River where we’ve, excavators have uncovered a number of human remains. The work that I have done on
these has been on the teeth, not on the bones, because
the teeth preserve better over long time periods like 110,000 years. The teeth are more chemically stable and so we can have more
confidence in the measurements that we make on them. What we’ve found in our analyses
of the teeth from Klasies is that back at about 110,000 years ago, some individuals were indeed
specializing in marine foods. Other individuals were not. And we’re seeing a wide range of variation that pretty much spans
the range of variation that we see in populations
dating to the last couple of thousand years. So it’s clear from this, that
we can push the beginnings of significant reliance on marine foods back beyond 100,000. We don’t know quite how far back yet but towards the earlier
period of the development of modern humans. And we wonder whether if there were marine
specialists back then, does that mean that populations back then were territorial as the same
way that the coastal hunting and gathering populations were in the last few thousand years? Does that mean that
we’ve got the same sort of anthropological correlates that we see in more recent time periods? I don’t know what the answer to that is, we’re working on it and
perhaps in a few years we will have some answers. Thank you very much. (audience applauds) (upbeat music)