Latest / The Smart Cookies podcast / NEANDERTHALS with Prof. Chris Stringer

Transcript

NEANDERTHALS with Prof. Chris Stringer · The Smart Cookies podcast

• 0:00
  It is with the utmost pleasure that I'm welcoming back to the show, Professor Chris Stringer,
• 0:08
  an anthropologist who's nothing short of a legend in the field of human evolution. Professor,
• 0:14
  really appreciate you coming back on.
• 0:16
  Okay, nice. Good to be with you again.
• 0:19
  Now since we last spoke, I hosted Harvard astrophysicists searching for extraterrestrial
• 0:24
  life, doctors studying near-death experiences. I even had a conversation with a former KGB
• 0:31
  spy. And yet, as far as numbers are concerned, whether we're talking audio downloads or views
• 0:38
  on YouTube, nothing comes even remotely close to the human origins episode I had with you
• 0:45
  almost two years ago, I think. It still easily reigns supreme. So it seems that when all
• 0:54
  is said and done, the questions we are most interested in are who we really are and where
• 1:00
  do we come from? Professor, is that perhaps the ultimate proof of the vanity or egotism
• 1:07
  of our species? Or am I being too harsh here?
• 1:10
  Yeah. I mean, yes, you could say it's vanity. But yeah, it's a curiosity too. We're a curious
• 1:15
  species and knowing where we came from. Yeah. Yeah. And unfortunately, of course, where
• 1:21
  are we going? That's another issue much more difficult to answer.
• 1:25
  Right. But most curious about ourselves. Yes. I mean, this is not like an empirical study,
• 1:31
  but yeah, I mean, I think we shouldn't be, of course, most interested in ourselves. We
• 1:35
  should be interested in all living things. We're part of the natural world. So I suppose
• 1:40
  that, you know, this is a way into looking at our place in nature, our place in the wider
• 1:46
  world. Yeah. So I don't see it just as being just about us. It's about our relatives, not
• 1:51
  only our dead ones, but our living ones too. So yeah, I think this should be part of our
• 1:57
  natural curiosity about why we're here and how we relate to the rest of the natural world.
• 2:04
  Thank you for putting it in a much healthier context than I did. I went straight to the
• 2:09
  Eastern European cynicism, but that's much more helpful. So last time we discussed the
• 2:15
  world of the five hominins species that at least for a while coexisted on this planet,
• 2:20
  which for us today seems kind of freaky, other types of humans running around. We're just
• 2:25
  not used to that. This time, however, I figured we would narrow it down to a group who probably
• 2:30
  intrigues us the most, at least, maybe at least I'm speaking just for myself. And that's
• 2:36
  our cousins, the Neanderthals. Okay. Let's start maybe with this. What would
• 2:42
  you say is the most misunderstood thing about the Neanderthals?
• 2:47
  Yes. So the place of the Neanderthals, their relation to us, it's a long and complicated
• 2:53
  story. And I think even though we try and make the point all the time that Neanderthals,
• 3:01
  at least in my view, are fully human, they are very like us in most ways. They shared
• 3:09
  a lot of our evolutionary history. Nevertheless, there is this long standing view of Neanderthals
• 3:15
  as representing this lesser kind of humanity, the brutal side, if you like, of humanity.
• 3:23
  Bad behavior, you know, unfortunately, it is still used as a term of insult. You know,
• 3:29
  we hear, you know, when footballers behave badly or football fans behave badly, they
• 3:34
  get called Neanderthals. When politicians get called Neanderthals, I mean, Trump's been
• 3:40
  called a Neanderthal. I think that's insulting to Neanderthals.
• 3:45
  Okay, fair enough. Let's go to the absolute basics. When do they appear and where are
• 3:53
  they coming from?
• 3:54
  It depends who you ask is the first answer really, because not everyone agrees on how
• 3:59
  to recognize what is a Neanderthal and where they came from. My views are changing too,
• 4:05
  so I think we've got a lot of new evidence recently. So I would say the Neanderthals
• 4:10
  are one of our closest relatives. So I might have said 15 years ago, they are our closest
• 4:17
  relatives in the fossil record. Now we know about these other people called the Denisovans
• 4:22
  that were living in Siberia until at least 50,000 years ago. So they are Neanderthals
• 4:30
  and us are all closely related and views differ on which of them is actually our closest relation.
• 4:37
  So whereas a lot of genetic data at the moment suggests that Denisovans and Neanderthals
• 4:43
  are closely related to each other, more closely related to each other than they are to us,
• 4:48
  I've been involved in a collaboration with a Chinese paleontologist called Zhiyun Ni
• 4:55
  working on a wonderful fossil from China known as Dragon Man, the skull of Homolonghi. And
• 5:02
  in our work, actually it's suggested that the Homolonghi group is more closely related
• 5:08
  to us than the Neanderthals are. And now it seems increasingly likely that the Homolonghi
• 5:14
  group are actually Denisovans. They're one and the same thing. So we've got this third
• 5:19
  lineage over in Asia. There's us having evolved in Africa over the last half a million years.
• 5:26
  There's the Neanderthals evolving in Europe and Asia over that same time period. And over
• 5:31
  in the Far East, we've got these people called the Denisovans. So it's unclear at the moment
• 5:37
  which of them are our closest relatives. And it's unclear when we have a common ancestor.
• 5:42
  So to say when the Neanderthals began, we need to know when we had a common ancestor
• 5:46
  with the Neanderthals. And the genetic data suggests it was maybe 600,000 years ago, which
• 5:53
  is a long time, but not a long time in terms of total Earth history. So on that basis,
• 6:00
  we think that geneticists estimate we separated from the chimpanzees maybe 7 million years
• 6:05
  ago in evolutionary terms. The Neanderthals then are 10 times closer to us than chimpanzees
• 6:11
  are. They share most of that evolutionary history until about 600,000 years ago. But
• 6:17
  my work on Dragon Man with Ziyun and me and colleagues suggests the common ancestor might
• 6:21
  be even further back. Could be closer to a million years. So that's the first issue.
• 6:27
  When did we have a common ancestor with Neanderthals? When did their lineage begin? It could be
• 6:31
  600,000 years. It could even be as far back as a million. And where did that common ancestor
• 6:37
  live and what was it like? So 10 years ago, I would have said the common ancestor is a
• 6:42
  thing called Homo Heidoburgensis. This is part of a description. It's a group of fossils
• 6:50
  that were around about 500,000 years ago. And we know of them from Europe and from Africa,
• 6:57
  probably from Asia too. And it includes things like the Cabway fossil from Africa, so-called
• 7:03
  Rhodesian man. It includes skulls from Greece, such as Petralona, from France, Aragio, from
• 7:11
  Ethiopia, Bodo. So in my view used to be that that species was the common ancestor of us
• 7:17
  and Neanderthals. And then it went in separate evolutionary directions. In Africa, it became
• 7:22
  us. In Europe and Asia, it became Neanderthals. Now, I don't share that view anymore. I think
• 7:29
  Heidoburgensis and the fossils we put in it and even the name is argued about what is
• 7:34
  the correct name for this group. I think that group actually don't represent our ancestors.
• 7:39
  I think it was a separate branch. And our common ancestor is more like a thing called
• 7:45
  Homo Anticesor, Pioneer Man, which is known from Europe from about 850,000 years ago.
• 7:54
  And the common ancestor then went in its different directions, but it wasn't Heidoburgensis.
• 8:00
  So views are changing and it depends who you are. So other people might start the Neanderthal
• 8:04
  lineage much later on. So the first fossils that we can really say are on the Neanderthal
• 8:09
  line are at the moment are ones from the Cima del Juesos in Spain. So the pit of the bones.
• 8:17
  So it's an incredible site. Deep in this cave system, there's a blind chamber deep in the
• 8:21
  cave and down there are over 6,000 human fossils from about 400,000 years ago. It's an incredible
• 8:30
  site. We think those bones ended up down there because humans 400,000 years ago, or slightly
• 8:37
  older than that, they threw bodies down into this pit deep in the cave. And incredibly,
• 8:42
  they've been preserved for all that time. They do show Neanderthal features, especially
• 8:47
  in their teeth. And there are even fragments of DNA from bones in this pit of the bones
• 8:53
  that actually show they are on the Neanderthal lineage. So about 430,000 years ago, which
• 8:59
  is the current dating for this collection of bones, they already, the Neanderthals were
• 9:03
  already evolving. And we assume therefore, in Africa, our ancestors, Homo sapiens, were
• 9:08
  already separate and evolving too.
• 9:13
  So the fossils are, what did you say, 430,000 years old?
• 9:17
  The ones in the Cimuntal Huessos, yes, in Atapueca, in northern Spain.
• 9:23
  Okay, interesting.
• 9:24
  But they're primitive, they're primitive Neanderthals. They don't show all the features of the later
• 9:30
  ones, but they certainly show some of the features, and particularly in their teeth.
• 9:34
  They show many of the distinctive features, wrinkles and the shape differences in the
• 9:38
  teeth, which we find later on in Neanderthals.
• 9:42
  Is it fair to say that the Neanderthals were more adapted to cold ice age weather?
• 9:47
  That's been a common view that, of course, they lived in overall colder conditions than
• 9:52
  our ancestors did in Africa, that's clear. But to what extent they were really obligatory,
• 10:00
  if you like, cold adapted is more arguable, because we know that they actually lived in
• 10:04
  warmer conditions as well. So in Italy, for example, we find Neanderthals alongside fossils
• 10:11
  of hippopotamus. So clearly, they were living in warmer conditions.
• 10:16
  And there was a period about 125,000 years ago in Europe, when it was slightly warmer
• 10:22
  than the present day. Well, we're coming to that warmth again now with global warming,
• 10:26
  but it was slightly warmer. And there were forests over much of Europe. And we now know
• 10:31
  the Neanderthals were doing well in that environment too. So they weren't just ice age people.
• 10:38
  We do find them later on alongside reindeers and woolly mammoths and things like that.
• 10:43
  So they could adapt to the cold. But they also were doing quite well in at least temperate
• 10:49
  conditions, not really hot, but southern European conditions, conditions in the Middle East,
• 10:56
  Western Asia, they were fine in those environments too. So not just cold adapted. And in fact,
• 11:02
  interesting, when it gets really cold, the Neanderthals disappear. So they weren't good
• 11:08
  in really cold conditions, then they vanish. And interestingly, the Denisovans, these other
• 11:13
  people that were living over in the Far East, it looks like they were actually possibly
• 11:18
  slightly better cold adapted than the Neanderthals, because there are what seem to be Denisovans
• 11:23
  living up in on the plateaus of the Tibetan Plateau. They were their remains from a cave
• 11:30
  called Baishia Cave in the Tibetan Plateau of China. And this is an altitude of 3000
• 11:38
  meters, extremely cold at times. And these Denisovans, we know from DNA and probably
• 11:44
  from fossils as well, it's a bit more arguable. They were living there 100,000 years ago in
• 11:50
  some quite cold conditions. The Harbin fossil, the Dragon Man fossil, which could be a Denisovan,
• 11:57
  it's up in Northeast China. And that has some of the coldest winters in China, even at the
• 12:01
  present day, the average temperature in winter is often minus 15 degrees. So Denisovans or
• 12:09
  Dragon Man, they were living up there in Northeast China 150,000 years ago. So possibly, yes,
• 12:16
  Neanderthals could live in cold conditions, but maybe these people in the Far East were
• 12:21
  living at times in even colder conditions. That's unexpected, because in the popular
• 12:25
  imagination, we always associate Neanderthals with extremely cold weather and ice age and
• 12:31
  so forth. And I thought that even their features, like broad noses, barrel chests, that these
• 12:38
  were all like adaptations to cold weather. But you're telling me that's not necessarily
• 12:43
  so.
• 12:44
  I mean, of course, the conditions overall, the ice ages dominated the climates of Europe
• 12:49
  and Asia for the last 500,000 years. So overall, the Neanderthals were living in colder conditions
• 12:56
  in the present most of the time. But when it got warmer, they didn't go away. They still
• 13:01
  did all right. But yes, that long term adaptation under colder conditions, an average today,
• 13:08
  may have shaped their bodies to be shorter and wider, which is a good shape to be in
• 13:12
  the cold. And in terms of their big lungs and so on, that's more likely an adaptation
• 13:19
  that all of these earlier humans had. It seems that, by contrast, homo sapiens is a kind
• 13:24
  of more, you know, more economical energetically than some of these earlier species. They were
• 13:31
  demanding more of their environment. You could say that perhaps their technology was not
• 13:36
  as efficient in taking away the demands made on the body to get food every day. All the
• 13:42
  activities we do, we have tools to help us with those activities. These earlier humans
• 13:47
  did not have such complex technologies. They had to put more physical effort into their
• 13:53
  everyday activities. So living was hard for these people. And their bodies were built
• 13:58
  to withstand that. They were somewhat heavier, somewhat more heavily muscled. And not just
• 14:04
  the Neanderthals, but Homo erectus and earlier species, their lung capacity could have been
• 14:08
  20% bigger than ours. And so that's an energetic demand. They just require that extra fuel
• 14:14
  for their everyday activities. So we could be a more economical species. Probably our
• 14:19
  technology has enabled us to reduce our body strength and our requirements for power and
• 14:25
  muscle compared with these earlier humans. So Neanderthals were part of that earlier
• 14:30
  kind of human that was still really requiring a bit more energy out of the environment in
• 14:36
  terms of food. Their overall organs, probably their body organs in the trunk, were all a
• 14:42
  bit bigger than ours, a bit more demanding than ours. So they could have had bigger hearts
• 14:48
  equally, bigger lungs, as we've said, bigger other organs processing food and so on. So
• 14:54
  their whole trunk was bigger, their pelvis was wider to support probably those larger
• 14:59
  organs in the middle of the body. So they survived throughout different types of climates,
• 15:04
  right? But even so, in general, generally speaking, you'd say that the conditions they
• 15:09
  had to survive in were much more harsh than ours. Well, of course, Homo sapiens today
• 15:15
  live in very harsh conditions. Think of the Inuit, think of the people up on the Tibetan
• 15:19
  Plateau today and think of people in the Sahara Desert. So we can live in even more harsh
• 15:24
  environments than these earlier humans. Oh wow, interesting. Because our technology enables
• 15:29
  us to survive in those conditions. But if we talk about early Homo sapiens, yes, if
• 15:33
  we talk about Homo sapiens 100,000 years ago, obviously we didn't live in all those
• 15:38
  extreme environments 100,000 years ago. Like the Neanderthals, when the weather got really
• 15:43
  bad, Homo sapiens died out as well. So these very rapid climate changes that were happening
• 15:51
  affected all human populations. And so human population numbers for Neanderthals and for
• 15:55
  Homo sapiens were by modern standards ridiculously small. At times we're talking of populations
• 16:02
  in the thousands or tens of thousands. In total, in the world. Maybe there could have
• 16:08
  been a million people worldwide 100,000 years ago of the different species. But by modern
• 16:13
  standards we were small in number. And at times the Neanderthals seemed to be very challenged.
• 16:19
  So from their DNA, we know that some of their populations were having to do breeding with
• 16:25
  close relatives. So they're inbred, their numbers are low, they're having to breed with
• 16:32
  close relatives. We know this from several sites where their DNA diversity is very low.
• 16:37
  Where close relatives are having to interbreed, that's obviously bad for the gene pool because
• 16:43
  you can build up bad mutations, it reduces your diversity. So Neanderthals near the end
• 16:49
  of their time probably were suffering. You could say they were an endangered species
• 16:53
  maybe even without anything to do with Homo sapiens competing with them. So I think that
• 16:59
  because of these really, you could say these climate changes that kept happening. So from
• 17:07
  about 100,000 years down to about 40,000 years. So that covers the last 60,000 years we think
• 17:13
  the Neanderthals were around. The climates in Europe were changing very rapidly. So it
• 17:19
  would be nearly as warm as today for maybe a thousand years, then it would suddenly plunge
• 17:24
  into extreme cold for a thousand years. And then it would switch back again. And this
• 17:29
  kept happening. So they were never able to keep their numbers up in the last 60,000 years
• 17:35
  of their existence in Europe. This eroded their numbers, it eroded their diversity.
• 17:41
  So I think by the time we get to 50,000 years ago, they were in trouble in terms of their
• 17:48
  gene pool being relatively small, their numbers being relatively small.
• 17:52
  Is there any evidence, probably not. I don't know if that's a ridiculous question that
• 17:56
  in these harsh conditions or like harsh weather or climate change, they would ever try to
• 18:02
  make it to Africa? Yeah, we don't know if the Neanderthals ever
• 18:06
  made it to Africa. There's no reason why they couldn't have got there. We know that they
• 18:10
  were in the Levant. So they were in southern Israel. So yes, there's a site called Shukba,
• 18:18
  which is a cave site. And I was involved in restudying a tooth from there, a molar tooth
• 18:22
  found in the 1930s. And that is a Neanderthal tooth. And that's only a few hundred kilometers
• 18:30
  from Cairo. So they were that close to Africa. So at times, I mean, they wouldn't have known
• 18:36
  it was Africa, of course, if they were at Shukba in southern Israel, they wouldn't,
• 18:40
  you know, they've got the Sinai in front of them. If it was actually relatively green
• 18:44
  and not desert, maybe they would have gone across it and gone into Africa. Maybe they
• 18:49
  did do that. We haven't got any evidence of it, but it's certainly not, you know, if
• 18:53
  Homo sapiens could at times move from North East Africa into that region, equally if the
• 18:59
  Neanderthals were there, why wouldn't they have been able to go in the opposite direction
• 19:03
  to Africa at times? We haven't got the direct evidence, but I certainly, yeah, there's no
• 19:08
  reason why Neanderthals could not have got into North Africa. Maybe they did. Only time
• 19:13
  will tell. That's right. New discoveries are going to find anything to show this. And maybe
• 19:17
  if they came into Africa, there could have been some interbreeding even there. So we
• 19:22
  know there's this strange sort of still poorly understood period of time when maybe 300,000
• 19:31
  years ago, it seems that early Homo sapiens met up with the Neanderthals and they did
• 19:37
  interbreed even at that time. We know about the later interbreeding and I'm sure we'll
• 19:40
  come on to that later, but it seems that there was a poorly known episode when Homo sapiens
• 19:46
  must have come out of Africa, maybe into Western Asia and met Neanderthals and interbred with
• 19:53
  them. And as a result of that interbreeding, Neanderthals picked up some Homo sapiens DNA
• 19:59
  in that interbreeding about maybe 300,000 years ago. So we can find evidence of this
• 20:04
  in Neanderthal genomes because if you look at the whole genome of Neanderthals, that
• 20:10
  suggests as I mentioned, a separation from us of maybe 600,000 years to a common ancestor
• 20:17
  on the genetic estimates. But if you look at the mitochondrial DNA, which is a bit of
• 20:22
  DNA inherited through females, and you look at the Y chromosome DNA inherited through
• 20:27
  males, if you look at the Neanderthal Y chromosome and mitochondrial DNA, the divergence only
• 20:32
  comes to maybe 400,000 years. So the suggestion is that that interbreeding maybe 300,000 years
• 20:41
  ago replaced the Neanderthals original Y chromosome mitochondrial DNA with one that's more Homo
• 20:49
  sapiens like. So they had a replacement of those bits of their genome by the Homo sapiens
• 20:55
  genome and equally that DNA probably went into Homo sapiens in the other direction about
• 21:01
  300,000 years ago. So it's a very poorly understood one, which we can only model at present on
• 21:07
  the DNA and possibly on the archaeology because around that time there was also a change in
• 21:14
  Europe and Western Asia and Africa from the kind of archaeology that was around before,
• 21:21
  which is often dominated by making hand axes. So these large bifacial tools, large cutting
• 21:28
  tools, these tools were very widespread in Europe and Africa and Western Asia until about
• 21:36
  300,000 years ago. And then we start to see a change to a thing called prepared core technology,
• 21:42
  Lavalois is sometimes called, where the people, instead of taking a piece of flint and knocking
• 21:49
  off lots of flakes until you get the thing you want, which is a hand axe, they would
• 21:53
  actually map out beforehand the shape of the tool they wanted and then with a single blow
• 21:59
  they could strike off a prepared flake close to what they wanted. So it was a different
• 22:06
  technique and it became widespread about 300,000 years ago. So possibly the knowledge of that
• 22:13
  technology spread between Neanderthals and Homo sapiens 300,000 years ago. So it's a
• 22:20
  very interesting story. And in terms of early Homo sapiens fossils out of Africa, I was
• 22:25
  involved in studying a fossil from Greece from a site called Epidema, Epidema cave in
• 22:31
  southern Greece. It's on the coast, it's a series actually in a stack of vertically stacked
• 22:37
  caves. And in one of them, in the roof of one of these caves, they found two skulls,
• 22:44
  which were thought to both be Neanderthal skulls. And I was involved in a re-study of
• 22:49
  these fossils led by Katarina Havati. And what she found with her work was that one
• 22:56
  of the skulls was Neanderthal and is thought to be about 170,000 years old. But the second
• 23:02
  skull, which is actually Epidema one, it's only the back of a skull, but it actually
• 23:06
  looks like a Homo sapiens back of a skull. It doesn't look like a Neanderthal. So that
• 23:12
  fossil is dated at least 210,000 years old. So this could be an example of an early Homo
• 23:20
  sapiens migration. It got as far as Greece more than 200,000 years ago, and it could
• 23:25
  be part of this population, the interbreed with the Neanderthals. So it's a more complicated
• 23:30
  story than we used to think. It seems that Homo sapiens made a number of excursions out
• 23:35
  of Africa before the final one, which is after 60,000. So the one at 60,000 years onward
• 23:42
  is the one that gives rise to all the diversity outside of Africa today. And it's also the
• 23:48
  one that had the main interbreeding event with Neanderthals that everyone outside of
• 23:52
  Africa shows evidence of today. Do we know anything about the social structures of Neanderthals?
• 23:57
  Let's say typically how many people were in a group? Was there a tribal leader? Did they
• 24:01
  practice patriarchy or maybe not? Was there division of labor between the sexes? Were
• 24:07
  they monogamous, etc.? I'm hitting you up with a lot of things. I know, but can we be
• 24:11
  certain about any of these? You need to speak to an archaeologist for most of those. I can
• 24:16
  say a little bit. I mean, obviously, Neanderthal groups, we think Neanderthals did not have
• 24:20
  as large social groups as at least later Homo sapiens. So their groups possibly were more
• 24:28
  limited, maybe 20 or 30 people at times. And in terms of their mating structures, we've
• 24:34
  got a little bit of genetic data that suggests that they imported females into the groups.
• 24:42
  So you've got these groups of male kin and the female individuals come in as partners
• 24:49
  from outside those groups. So when you look at the DNA of Neanderthals from a few sites,
• 24:56
  you can see where you've got a number of individuals that the male individuals seem to be closely
• 25:00
  related, but the female individuals are less related to each other. So this is a thing
• 25:06
  sometimes called patrilocal mating, which we find in many human groups today. So it's
• 25:14
  only slender evidence. Neanderthals seem to have done that at times. Whether it was universal,
• 25:19
  we don't know. But because that's interesting, because it would have been if that was what
• 25:22
  happened, then it would be the females bringing in knowledge from these other groups. So it's
• 25:27
  a way of information sharing. Females would have been the bearers of maybe new behaviours
• 25:33
  into those Neanderthal groups. But it seems that Neanderthals, their footprint on the
• 25:39
  landscape was smaller than the footprint of Homo sapiens from the same time periods. So
• 25:45
  when we look at the movements of raw materials, so we think of things like the material they're
• 25:50
  using to make stone tools, such as flint, we can track where that flint's come over
• 25:55
  a long distance from the isotope, from the chemical composition of the flint, you can
• 26:00
  map where it's come from. And in Africa, you could do the same thing for larvas and other
• 26:06
  raw materials. And the picture is that Homo sapiens seems to be extending wider across
• 26:10
  the landscape in terms of networks of trading and movement compared with Neanderthals. So
• 26:16
  Neanderthals probably live more locally. And that also may have had implications for their
• 26:23
  technology because obviously, if you're in a smaller area and a smaller mating network,
• 26:29
  that may affect your innovation. So new behaviours may not arrive at the same rate as they would
• 26:35
  do if you had a wider footprint on the landscape.
• 26:39
  But that was fascinating when you said that they met up to exchange women.
• 26:43
  Yes, so it looks like women, obviously, we don't know the exact mechanisms. And obviously,
• 26:47
  you asked about whether they were, did they just have single partners? We don't know anything
• 26:54
  about that. Of course.
• 26:57
  Maybe they did, but we can't actually say. But yes, females came into the group from
• 27:04
  the outside. That's the pattern which we can, where we've got information, we can say that
• 27:09
  was the pattern. But of course, if we have more data, we may find that there were equally
• 27:13
  examples where Neanderthal males migrated. And you had a female kinship system where
• 27:20
  females were closely related and the males came into the groups. That pattern could be
• 27:25
  there. But at the moment, we don't have examples of it from the Neanderthals.
• 27:29
  Well, is that a way to diversify their DNA pool? Is that what they did?
• 27:34
  Well, yeah, of course, we've mentioned that having to breed with your close relatives
• 27:39
  is bad news for the gene pool. Neanderthals at times were forced to do that. We've got
• 27:44
  examples of Neanderthals as closely related as an uncle and a niece interbreeding or half
• 27:51
  siblings having to interbreed. That's bad news for the diversity. So at times Neanderthals
• 27:58
  were having to breed with their very close relatives. But generally speaking, the diversity
• 28:03
  is obviously maintained by bringing in partners from a wider network.
• 28:08
  What about culture? Is there any proof that Neanderthals, for example, did the things
• 28:12
  that we do or similar things like dancing, playing music, making instruments, jewelry,
• 28:18
  religion?
• 28:19
  Yeah, it's very tricky to know about some of those things. Neanderthal behavior was
• 28:25
  certainly more complex than we used to think. 20 years ago, I would have said there's a
• 28:30
  big behavioral gap between us and Neanderthals. They didn't make much use of raw materials
• 28:36
  like bone and antler and ivory. They didn't do any art and things like that. Now the gap
• 28:44
  between us and Neanderthals is much narrower. Some people say it's disappeared altogether.
• 28:48
  I don't go that far because there are some examples of Neanderthal markings on cave walls,
• 28:55
  engravings as a thing called the hashtag, which seems to be made by Neanderthal in Gibraltar
• 29:00
  maybe 40, 45,000 years ago. There are engravings on bones, zigzag marks and so on, and linear,
• 29:10
  what might be counting marks on some bones. So Neanderthals were doing that. But as far
• 29:16
  as I know, at least in my view, there's no representational art produced by the Neanderthals.
• 29:21
  So when we come on to 35,000 years ago, we've got lots of evidence of Homo sapiens. Even
• 29:27
  earlier than that, there's caves in Sulawesi where it seems that Homo sapiens was painting
• 29:33
  animals on the cave wall 45,000 years ago. Pigs, wild pigs, for example. And we have
• 29:40
  the cave paintings in France at 35,000 to 40,000. Neanderthals, as far as we know, and
• 29:46
  also statuettes, I should say, from 40,000 years ago in Germany, we have lovely little
• 29:50
  statuettes of animals made of mammoth ivory and even a female figurine from Germany at
• 29:57
  about 40,000 years. There's no evidence of that for Neanderthals. So at the moment, it
• 30:01
  doesn't look like they produced representational art, which seems to be unique to at least
• 30:08
  later Homo sapiens. But they were marking cave walls. They did apparently mark things
• 30:15
  symbolically. So making these zigzag markings meant something to the maker, and probably
• 30:20
  they were transmitting a message to another individual. So it's symbolic of some message,
• 30:25
  which we can't interpret. So Neanderthals had that complexity. We know that they did
• 30:31
  make more complex tools. They certainly mounted spear points onto handles. We know there's
• 30:37
  evidence even of adhesive that Neanderthals were making to keep these tools together.
• 30:44
  There's a site called Schöningen in Germany dating from around 300,000 years ago, where
• 30:50
  you have the very rare preservation of wooden tools. And it's really quite striking just
• 30:55
  what a variety of tools were being made of wood 300,000 years ago. And we don't actually
• 31:00
  know the species that made those tools because this other species, Homo heidoburgensis, was
• 31:08
  also around in Europe at that time. So it could have been heidoburgensis. It could have
• 31:12
  been Neanderthals making, early Neanderthals making those wooden tools. But they are a
• 31:16
  variety of tools made very skillfully by people who really knew the material they were working
• 31:21
  in. Choosing specific trees, a specific species of tree, a specific kind of tree, and then
• 31:28
  spending a lot of time working on these to make spears, throwing sticks, digging sticks,
• 31:35
  and other kinds of artifacts out of wood. So most of that evidence has disappeared because
• 31:39
  wood doesn't survive well. But that shows us the complexity of Neanderthals and their
• 31:45
  predecessors. And things like marine exploitation. Again, 20 years ago, it seemed that Homo sapiens
• 31:51
  were the ones that were really exploiting the marine resources and Neanderthals didn't.
• 31:56
  We now know Neanderthals were exploiting marine resources at times. Neanderthals living on
• 32:01
  the coast were collecting shellfish and they were eating even marine mammals at times.
• 32:07
  Many species of dolphin are found there, of seal. Now because they may have scavenged
• 32:11
  some of these, maybe a dolphin washed up near the cave, but they ate it. But they certainly
• 32:15
  collected enough shellfish that they were purposely doing that. And they were, in Gibraltar
• 32:20
  we found evidence of Neanderthals taking limpets and then baking them as people do today.
• 32:27
  As your fire is dying down, you drop your limpet shells into the fire and they open
• 32:32
  up naturally from the fire. And that's what Neanderthals seem to have done in Van Gogh
• 32:38
  cave in Gibraltar. Smart people. So they were much more like us than we used to think. And
• 32:45
  that's why this old image of the brutal Neanderthal, the ape-like Neanderthal that used to be around,
• 32:50
  we have to throw that out certainly. What kind of clothes did they wear? Well, unfortunately
• 32:55
  the evidence of that has disappeared. I'm sure they must have had clothing. They were
• 33:00
  certainly, they had the technology to work animal skins and they must have worn clothing
• 33:07
  at times when it was really cold. Maybe they didn't when it was warm, they didn't need
• 33:10
  to, but perhaps it's comfortable to cover bits of your body if you're going through
• 33:15
  some coarse vegetation. If you're wearing clothing, that will protect you a bit. Maybe
• 33:22
  they had shoes, but again, not direct evidence of that. But yes, I'm sure they had clothing
• 33:27
  when it was really cold, of course, they must have had clothing. Maybe they didn't have
• 33:34
  sewing needles. Perhaps that's something that came with Homo sapiens. And if you've got
• 33:38
  sewing needles, you can produce better insulation for your clothing, for your tents, for your,
• 33:44
  to cover your baby, to keep your baby warm, which is critical for survival. So maybe they
• 33:49
  didn't have that, but I'm sure they had clothing. I'm sure they were skilled at working animal
• 33:54
  skins. Yeah. You mentioned the hashtag that was carved into a rock, I believe by Neanderthal.
• 34:01
  Yes. And since they were so similar to us and you're saying that the difference that
• 34:07
  we thought was once there is getting narrower and narrower, is it reasonable to assume then
• 34:12
  that they had language similar to ours? I'm sure they were talking to each other. I think
• 34:18
  the language, of course, again, there are experts in this that you could talk to. But
• 34:22
  for me, I think the complexity of Neanderthal life as we know it, means they must have had
• 34:28
  language. I think if they're doing corporate hunting, for example, then that suggests they've
• 34:34
  got language, complex communication. But of course, if they really separated from us more
• 34:39
  than half a million years ago, their language could have evolved in such a different way
• 34:45
  than it would be unlike any language we can imagine today from the diversity of languages
• 34:49
  around the world today. So what that language was like, we can't say. I think it was probably
• 34:54
  a practical language for what they, you know, it was based on their everyday activities,
• 34:59
  what they were doing now, maybe what they were doing tomorrow. It probably wasn't a
• 35:02
  language that had, you know, very complex terminology. It didn't maybe have a lot of
• 35:08
  abstractions. It didn't talk about the deep past or the distant future. It didn't probably
• 35:15
  talk much about imaginary worlds, but it was probably a practical language. And I'm sure
• 35:19
  they had that capability. And there's one side I haven't mentioned in terms of Neanderthal
• 35:25
  complexity. So there's a remarkable site deep in a cave, Brunickel cave in France. Deep
• 35:33
  in the cave, well beyond any daylight, explorers found two oval structures made out of stalagmites.
• 35:42
  So someone had systematically broken stalagmites and built dry stone walls in oval shapes.
• 35:52
  They'd had fires down there because it was completely black, so completely dark. So they
• 35:56
  must have had fires. And there's evidence of these fires of them burning both charcoal
• 36:01
  and animal bones and animal fat for these fires. When these stalagmites were dated,
• 36:07
  these stalagmite rings, they were dated to 176,000 years ago. Deep in this cave. And
• 36:14
  at that time in Southern France, we only think Neanderthals were around. So very likely this
• 36:18
  was made by Neanderthals. Why they did it deep in the cave, some people think this is
• 36:23
  some religious structure, some ritual structure. I think they could have actually been living
• 36:30
  down there at times because 176,000 years ago was pretty cold. It might have actually
• 36:36
  been warmer in the cave, sheltered. Okay, they'd have needed fires to keep burning down there.
• 36:44
  But maybe actually these are hut structures. The floor has not been excavated yet. And
• 36:49
  so we don't know if they will be living debris down there, where they're actually living,
• 36:55
  or were these some special ritual structures. So there's a lot to learn about that. But
• 36:59
  it shows the complexity and the fact that they've gone and systematically broken stalagmites
• 37:05
  to a given size to build these walls. Again, that's cooperative behavior. That wasn't
• 37:10
  just one or two people doing that. It was groups. And again, that suggests language
• 37:14
  to communicate something as complex as that. And back to your question about music. I know
• 37:19
  I didn't answer that one, whether they could have had music. There's a controversial flute
• 37:27
  made out of cave bear bone from a site called Juvbabe. And that is claimed to have been
• 37:34
  made by a Slovenian site. That's right. So there are holes. Yeah, I'm from Slovenia.
• 37:40
  So there are holes in this bone, which seem to be spaced out as though it is a flute.
• 37:45
  And people have replicated it and played it as a flute. But other archaeologists have
• 37:51
  looked at these holes and think that they've been produced by animal teeth. So cave bear
• 37:57
  teeth and hyena and lion teeth fit into those holes equally. So it could be an accidental
• 38:03
  product that we recognize as a musical instrument. So I'm cautious about that being a musical
• 38:09
  instrument. And the best ones who know about come from 40,000 years onwards. So when we
• 38:13
  come to homo sapiens in Germany, for example, there are flutes made out of vulture bones
• 38:21
  and even out of ivory, very difficult material. And those undoubtedly are musical instruments.
• 38:26
  For Neanderthals, yeah, I'm sure they had some kind of music. I mean, those people who
• 38:31
  are breaking off all these stalagmites deep in that cave, you can even play stalagmites
• 38:36
  like xylophones. So I don't see why the Neanderthals couldn't have been drumming in those caves
• 38:42
  with stalagmites. They'd make a nice ringing sound. Why not?
• 38:48
  Okay, we talked a lot about how similar we are to Neanderthals as homo sapiens. But yet
• 38:55
  we are not the same. What are some of the differences between us and them?
• 38:59
  Well, obviously, in the skeleton, we talked a bit about the body shape. So if we look
• 39:03
  at their skeletons, like the barrel chest, the bigger organ, they're short and wide,
• 39:08
  very muscular, deep muscle insertions, very powerfully built, especially in the upper
• 39:12
  body. This, as you say, barrel chested and much bigger lungs in there, wide shoulders.
• 39:18
  In the head, there are a number of differences. And my PhD was about looking at the skull
• 39:22
  of Neanderthals and homo sapiens and comparing them, looking at the similarities and differences.
• 39:28
  So they've got a big brain as big as ours. It's a different shape, though. It's longer
• 39:32
  and lower. So the brain case is longer and lower. There's of course this characteristic
• 39:37
  big brow ridge at the front, which all of these earlier humans have got. So lower. And
• 39:43
  their face, of course, very distinctive. We talked about this before. I know. I think
• 39:47
  you mentioned it on your Twitter feed about the big Neanderthal nose.
• 39:53
  I asked you if you can tell if I have more Neanderthal DNA because of my big nose.
• 39:57
  A lot of us have got big noses, prominent noses and wide noses. And the fact is Neanderthals
• 40:07
  had really extraordinary noses. The nose was pulled forwards. It was very high and it was
• 40:12
  very wide. And that's really unique to them as a group. And it was accentuated because
• 40:20
  the middle of the face is pulled forwards and the cheekbones sweep back. So I think
• 40:24
  if we could have seen a Neanderthal coming towards us, that nose would have been one
• 40:27
  of the most striking features that we would see first. So why it's there, some people
• 40:34
  think it could be respiration, that it helped them, you know, breathing a lot of air in,
• 40:41
  maybe warming or humidifying the air. But it could also just be functional, that they
• 40:45
  require a lot of air to come in. And so that big nasal opening is letting them get air
• 40:50
  down to their lungs. So they're having to breathe in a lot of air and that nose is part
• 40:55
  of that system. So yeah, so this distinctive face with the middle pulled forwards, not
• 41:00
  much of a chin on the lower jaw, little distinctive muscle markings from one skull, from their
• 41:08
  skulls compared with ours, and the ear bones. So the middle ear and the inner ear, tiny
• 41:13
  little bones in there, which are concerned with our balance and with our hearing. The
• 41:18
  middle and inner ear bones of Neanderthals are in different shape to ours. And so from
• 41:23
  CT scanning, even though when we haven't seen the bones, because they're buried inside the
• 41:27
  skull, we can tell that Neanderthals were different from us in their ear bone shapes.
• 41:32
  And these ear bone shapes are laid down before birth. So the fetus already has these ear
• 41:36
  bone shapes laid down and it's different in Neanderthals. So Neanderthals and us are more
• 41:42
  different in ear bone shape than gorillas are compared with chimpanzees. So it's a very
• 41:47
  striking difference. What does it mean? Well, functionally probably doesn't mean much. So
• 41:52
  the hearing range, we can estimate the hearing range and it's been done for the people at
• 41:56
  Atopueka in the Cima de los Huesos. So we have their ear bones from more than 400,000
• 42:02
  years ago. And already at that time, their hearing range was very similar to ours. So
• 42:08
  there's no evidence these hearing bone differences are to do with inferior or superior hearing.
• 42:16
  But it may be that it's just the whole shape of the head is different in Neanderthals.
• 42:22
  They've got a longer and lower skull, which is almost spherical in shape. And so the ear
• 42:27
  bones, which sit down here, they've got to continue to function. Even as the skull is
• 42:31
  a different shape, they've got to continue connecting to each other. So it may just be
• 42:36
  that that's the way they evolved over several hundred thousand years as the skull shape
• 42:41
  evolved to be different from ours. So their ear bones had to keep up with that change,
• 42:45
  if you like, and had to change their shape as well. But it is a distinctive feature.
• 42:50
  So that's in their skeletons. Obviously, we've talked a bit about their culture and
• 42:56
  how it may have been similar to ours in many ways, but with some differences. Their genetics,
• 43:02
  of course, their DNA is different in some ways from ours. There are bits of DNA they
• 43:06
  have and we don't have and we have and they don't have. So when we look at the interbreeding,
• 43:12
  and I don't know how much we're going to be able to talk about the interbreeding between
• 43:16
  us and Neanderthals. But what's interesting is when you look at the DNA today of humans
• 43:24
  today and where the Neanderthal DNA is in our modern genomes, much of it is just scattered
• 43:30
  right through our genomes and different people have different bits of Neanderthal DNA in
• 43:34
  them. And equally, the Denisovans in the Far East, they've interbred with Homo sapiens
• 43:40
  and people in the Far East and Southeast Asia and Australia and so on, they've got Denisovan
• 43:46
  DNA in them. So when you look at the Denisovan DNA, equally, it's scattered right through
• 43:50
  genomes of people today. But there are areas of the genome where you never find Neanderthal
• 43:57
  or Denisovan DNA, so-called deserts of introgression, deserts where there's no sign of Neanderthal
• 44:04
  or Denisovan DNA. And we know functionally that those areas of the genome contain coding
• 44:11
  for the brain and for the vocal tract. So that does suggest there was something that
• 44:16
  couldn't be tolerated in the hybrids in those areas. So hybrid DNA could not be tolerated
• 44:22
  in those bits of the genome. So they give us a clue that there were some functional
• 44:26
  differences in the genomes between us and Neanderthals and Denisovans. What they are
• 44:31
  exactly we don't know. But in many ways, obviously, the interbreeding was compatible. Otherwise,
• 44:37
  there wouldn't be Neanderthal DNA today. You and I probably have around 2% Neanderthal
• 44:42
  DNA in our genomes from interbreeding maybe 50,000 years ago.
• 44:46
  I just wanted to ask you this about the differences, maybe connecting those with culture. Is it
• 44:53
  true that throughout the, I don't know, 300,000 year history they existed, maybe it was even
• 44:58
  more, they managed to survive different climates, but their culture and their tools didn't really
• 45:03
  change. So unlike us, they didn't invent new stuff regularly.
• 45:07
  Well, I think it's difficult to say. In terms of stone tools, yes, the stone tools don't
• 45:13
  change dramatically. When we get to Homo sapiens from 45,000 years ago, we see much greater
• 45:19
  complexity. Many new tools, many new cultures and differences grow up quite rapidly. It
• 45:25
  looks like change is accelerating and building on change. So it kind of really takes off.
• 45:31
  And much greater use of bone and antler and ivory, which are difficult to work materials.
• 45:35
  But the Neanderthals did change through time. And there are different Neanderthal technologies.
• 45:41
  So there are so-called, we see Neanderthal tools described as Mycoccian or Zelecian,
• 45:50
  Chattelperonian and so on. So there are these subgroups of Neanderthal tool types, which
• 45:56
  are recognized by archaeologists. So these may represent distinct Neanderthal populations
• 46:01
  that carried on through time with their own distinctive traditions. But yes, innovation
• 46:07
  was slower. You could say the same thing for Homo sapiens though. If we look at change
• 46:12
  in Africa of stone tools, between let's say 300,000 and 100,000, there is not much change
• 46:18
  even in Africa in the stone tools. There may be a lot going on under the surface that we
• 46:22
  can't see in the stone tools, but the stone tools themselves do not show remarkable diversity
• 46:27
  until later on. From around 45,000, we suddenly see a proliferation of new tool types in Homo
• 46:36
  sapiens. But earlier on for us and the Neanderthals, the pace of change was in stone tools, at
• 46:43
  least as much slower.
• 46:44
  You mentioned that you and I probably have about 2% of Neanderthal DNA, so implying that
• 46:50
  different populations today have different percentages of Neanderthal DNA in them. I
• 46:55
  remember when I was going to university, one of our cultural anthropology professors told
• 46:59
  us of a 19th century theory of some French anthropologist, his name totally escapes me
• 47:05
  now, who was convinced that us Balkan people have much more Neanderthal blood, today we
• 47:11
  would say DNA probably, than anybody else. I think it was because they thought there
• 47:15
  was a group of Neanderthals that managed to survive in the Balkan mountains until very
• 47:20
  late or something. But which populations actually do have more Neanderthal DNA? And I'm totally
• 47:25
  going to rock my new Neanderthal identity if you say it was the Balkans.
• 47:30
  Yes, it wasn't the Balkans, I'm sorry to say. It wasn't anywhere in Europe, in fact, as
• 47:35
  far as we know. So again, you need to talk to a geneticist to get the precise figures.
• 47:39
  But first of all, the lowest levels of Neanderthal DNA are found in sub-Saharan Africa. So Neanderthals
• 47:46
  never penetrated, even if we mentioned they might have got into North Africa, perhaps,
• 47:51
  but they never penetrated far south. So modern sub-Saharan African populations have very
• 47:56
  low levels of Neanderthal DNA, unless it's been introduced more recently, more recently
• 48:01
  into breeding. So the highest levels actually are found surprisingly in places like China.
• 48:08
  That's kind of surprising when you think where Neanderthals were mainly living. And there
• 48:13
  were views that perhaps there were Neanderthals living in eastern Asia. And as Homo sapiens
• 48:20
  spread eastwards, they actually interbred with Neanderthals and added on a bit more
• 48:25
  Neanderthal DNA. That now seems to be much less likely an explanation. The explanation
• 48:30
  seems to be that the percentage in Europeans has been diluted. So we've had gene pool around
• 48:36
  the Mediterranean, which has brought in sub-Saharan African populations that had less Neanderthal
• 48:44
  DNA. Populations in Arabia and places like that may have had less Neanderthal DNA. And
• 48:50
  so actually, there's been gene flow that's diluted the formerly higher levels. So it's
• 48:55
  only a small amount. The Chinese, you know, maybe about 0.2 or 0.3% on average higher
• 49:01
  than Europeans. But it could be that the European level has actually been reduced slightly by
• 49:06
  later interbreeding with the Roman Empire, but the spread of Islam, all these changes
• 49:11
  of farmers coming from the Levant into Europe, bringing new behaviors and bringing their
• 49:17
  DNA. So it's diluted the European. So the figures probably were all higher 45,000 years
• 49:24
  ago, soon after the interbreeding, there was probably a level amount of Neanderthal DNA,
• 49:29
  and maybe 5% across the area. And then it's gradually been selected away. And in Europe,
• 49:35
  it's been diluted down even further to around that 2% level, slightly higher in China.
• 49:41
  Let's talk about that interbreeding event that happened. When did you say it was because
• 49:45
  there were several?
• 49:46
  Yes, so we think one was 300,000.
• 49:47
  We think there was one, maybe 300,000 or more years ago, still poorly known, which took
• 49:57
  some Sapiens DNA into Neanderthals and maybe a bit of Neanderthal DNA into Sapiens around
• 50:02
  the Mediterranean and North Africa. And then there was the main event. So Homo Sapiens,
• 50:09
  having made a few excursions out of Africa and spreading out of Africa now and again,
• 50:14
  around 60,000 years ago on genetic estimates, a population came out of Northeast Africa.
• 50:20
  And that was the population that interbred and had the main interbreeding event with
• 50:24
  Neanderthals, which is what's in our DNA today outside of Africa. So it could have happened
• 50:29
  maybe 50,000 years ago, probably somewhere in Western Asia. And then as the Homo Sapiens
• 50:35
  population spread out from there, they took that bit of Neanderthal DNA with them into
• 50:39
  Europe, towards China, down into Australia, over into the Americas eventually. And so
• 50:47
  that level was obviously, I've mentioned it could have been 5 or 10% to begin with, but
• 50:51
  it very rapidly was selected down to the levels we find it today, closer to 2%. But that 2%
• 50:59
  remains, much of it is not doing anything. It's just sitting there in our DNA, but some
• 51:05
  bits are functionally active. And so we now know that our immune systems outside of Africa
• 51:11
  owe something to Neanderthal DNA. It actually helped our immune systems. So when you think
• 51:19
  about it, obviously coming out of Africa, we had no natural immunities to the diseases
• 51:23
  that were local to Europe and Asia. The Neanderthals have been evolving there for hundreds of thousands
• 51:28
  of years and had developed natural immunities to the local diseases, to the parasites and
• 51:33
  so on. By interbreeding with the Neanderthals, we got a quick fix to our immune system. And
• 51:38
  that helped us 50,000 years ago. Nowadays, it's not quite so useful because it seems
• 51:43
  that some of those Neanderthal immune systems are behind some autoimmune diseases that we
• 51:48
  have today. So Crohn's disease, yeah, so things like Crohn's disease, biliricirrhosis, some
• 51:55
  of these may be due to the presence of Neanderthal DNA. There's even a peculiar correlation at
• 52:01
  a small level with addictive behavior in having Neanderthal DNA. Yeah, that the inability
• 52:08
  to give up smoking, there seems to be some connection with Neanderthal DNA, which seems
• 52:13
  odd because there was no tobacco around when we met Neanderthals 50,000 years ago. It came
• 52:17
  from the New World. But it could be something about repetitive behavior. So maybe Neanderthal
• 52:25
  cells, maybe if you're going to make a fire, you really have to persist at it to do it.
• 52:30
  And maybe that was something that was useful, that kind of persistent behavior. Nowadays,
• 52:34
  of course, bad news for us with betting shops and online betting around the corner and alcohol
• 52:41
  and tobacco and all those things. So it could be that that's what it is. And of course,
• 52:47
  people start listing all the things that may be due to having Neanderthal genes, being
• 52:52
  a moaning person, being bipolar, being depressed, whatever, whatever. These could all be due
• 53:00
  to Neanderthal DNA, people say. And you might think, well, no wonder the Neanderthals died
• 53:04
  out. They had all these things wrong with them. But of course, that's what the DNA
• 53:08
  is doing in our genomes today. We want to know what it was doing. What were those genes
• 53:14
  doing in Neanderthal genomes? And we don't know, of course. And genes don't work in isolation.
• 53:19
  They work together. So of course, in our genome, some of these bits of DNA may not be working
• 53:24
  the way they should have been working in Neanderthal genomes, because they've been transferred,
• 53:29
  if you like, to a foreign genome. So we'd like to know what those bits of DNA were doing
• 53:35
  for Neanderthals. And we don't know the answer to that.
• 53:38
  So when you send your DNA to one of these testing companies and it comes back, whatever,
• 53:43
  3% Neanderthal, does that actually tell you something or is that more of a commercial
• 53:48
  product?
• 53:50
  Doing whole genomes now is much cheaper. So if you can get your whole genome done, then
• 53:56
  you'll get a pretty accurate count of your Neanderthal levels. But of course, the commercial
• 54:00
  ones tend to select bits of the genome. So you get a figure that's approximate. So I've
• 54:06
  had it done twice. And I think one of mine was about 2.5% and one of them was 1.7%. If
• 54:12
  I average those, it's about the right level. So you get a rough guide, but it may not be
• 54:18
  perfect. You need your whole genome done to get the most accurate figure.
• 54:22
  But would that tell you anything about your behavior or anything?
• 54:27
  Well, some of these will give you extra information about your health. What are your risk factors
• 54:33
  to develop some of these diseases? And that is where they can be linked with Neanderthal
• 54:38
  DNA. They don't necessarily spell that out. But it may be that if you have a higher risk
• 54:45
  of developing a particular cancer, that could be due to bits of Neanderthal DNA. We know
• 54:51
  that COVID susceptibility, there are some bits of Neanderthal DNA which gave people
• 54:57
  protection against COVID and other bits that made them more susceptible. And this may be
• 55:02
  due to previous selection. So for example, we've had these plagues which have swept through,
• 55:07
  of course, Europe many times. There might have been bits of Neanderthal DNA which gave
• 55:11
  resistance to those particular diseases 500 or 1000 years ago. And now, of course, they
• 55:19
  may be doing the same thing for better or worse with a disease like COVID.
• 55:23
  Professor, we once thought, at least I was taught that in school, that once Homo sapiens
• 55:29
  turns up, we kind of supplant, if not exterminate, Neanderthals. But you told me that they were
• 55:36
  already on a downhill slope, that they already had weaker numbers, weaker DNA pool. So is
• 55:45
  it the other way around now? We had nothing to do with their demise?
• 55:49
  I mean, again, it depends who you ask. So I think that it's a combination of features
• 55:54
  that the Neanderthals disappeared physically, because they didn't disappear completely,
• 55:58
  because their DNA, as we've said, lives on in us today. But I think it was a combination
• 56:04
  of features. We've mentioned, yes, they're low diversity, but near the end of their time,
• 56:09
  they perhaps were a threatened species, and it wouldn't have needed much to tip them over
• 56:13
  the edge. The climate was very unstable. That certainly didn't help them. To have a competing
• 56:18
  species that turns up, that's going to want to, you know, it's going to be hunting, they're
• 56:24
  going to be hunting the same foods, collecting the same plant resources, wanting to live
• 56:28
  in the best territories for hunting and gathering, wanting to live in the best cave sites, and
• 56:32
  so on. So I think there was an economic competition between these two groups. And depending on
• 56:38
  the local circumstances, at times, maybe it favored the Neanderthals, and at other times,
• 56:42
  it favored homo sapiens. But overall, homo sapiens grew their numbers at the expense of
• 56:47
  the Neanderthals. And I think there's a clue also even in the interbreeding. So I wrote
• 56:53
  a paper a couple of years ago with my colleague, Lucille Cret, and we argued there that even
• 56:58
  the interbreeding could have been part of Neanderthal extinction, because there's a strange
• 57:02
  pattern at the moment in the interbreeding that happened after 50,000 years ago. So we
• 57:07
  have early homo sapiens genomes from after 50,000 years ago, and all of them show evidence
• 57:13
  of recent Neanderthal interbreeding, at least within the previous five or 10,000 years,
• 57:18
  sometimes even within a few generations. We have maybe a dozen Neanderthal genomes from
• 57:24
  the same time period. None of them show homo sapiens DNA coming in recently. So that's a
• 57:31
  strange pattern. It may just be due to low samples of having... We don't have many Neanderthal
• 57:36
  genomes, but at the moment, it seems to be a one-way pattern of Neanderthal DNA going
• 57:41
  into homo sapiens and not in the other direction. It may be that there simply wasn't interbreeding
• 57:47
  in both directions, that whatever mating patterns were going on, homo sapiens, Neanderthal people
• 57:55
  were joining, they're choosing to join the homo sapiens groups to interbreed. It may
• 58:00
  have been even capturing individuals. So some modern primate groups, some modern hunter-gatherer
• 58:07
  groups, if they run out of females, they will go and steal some from a neighboring group.
• 58:13
  So maybe homo sapiens actually stole Neanderthal females into their group to breed with them.
• 58:19
  Wow, fascinating.
• 58:22
  Whether it was voluntary or not, this movement of Neanderthal breeding individuals into homo
• 58:27
  sapiens means that they're being lost from the Neanderthal breeding pool. And if you
• 58:31
  haven't got many people, that's very bad news. If you're losing your prime age breeding
• 58:36
  individuals to this other population, that is going to add to the extinction problem.
• 58:43
  The numbers are going to shrink, the diversity is going to shrink because your prime age
• 58:46
  individuals are going voluntarily or involuntarily to join the breeding pool of another species.
• 58:53
  So if I understand you correctly, their demise is due to many complicated factors.
• 58:58
  Yes, it is. Climate change could be certainly part of it. Diseases, of course, brought by
• 59:04
  homo sapiens, equally diseases from Neanderthals and Denisovans. It could go both ways. Some
• 59:10
  people suggested epidemics, but I don't think that's going to be the explanation. And what
• 59:16
  we've got to do, of course, is account for not only the disappearance of Neanderthals,
• 59:20
  but of course, we've mentioned these other humans, the Denisovans, they disappeared too.
• 59:25
  And there were other human species around in Southeast Asia, they disappeared too. So
• 59:30
  the common factor, of course, seems to be the spread of homo sapiens. So that's why
• 59:34
  I think we are implicated. But it doesn't mean we were hunting these groups to extinction,
• 59:39
  fighting them and killing them, maybe eating them, they get even worse. I think that it's
• 59:44
  indirect, it's economic competition. And at times these groups coexisted probably peacefully,
• 59:51
  maybe they exchanged partners peacefully. But the long term pattern was Neanderthal decline
• 59:58
  and physical extinction.
• 59:59
  Okay. Yeah, I mean, that image of like all homo sapiens banding together with a plan
• 1:00:04
  to exterminate all Neanderthals was a bit silly to begin with, to be honest.
• 1:00:09
  I certainly think so. And equally homo sapiens are pretty good at doing each other in, we
• 1:00:14
  know that it's not just killing Neanderthals.
• 1:00:17
  Word. Yeah. Okay, we're approaching the end, Professor. So I hope you'll allow me to steer
• 1:00:23
  the conversation in different direction for just for a couple of minutes that we have
• 1:00:27
  left. You're probably too busy with actual work to listen to podcasts and watch Netflix.
• 1:00:33
  And there's been a big surge of these kind of pseudoscientific crackpot human origin
• 1:00:40
  theories in the mainstream lately, stuff like ancient aliens and that annoying guy Graham
• 1:00:46
  Hancock who's regularly appearing on Joe Rogan's podcast and even has a shockingly bad Netflix
• 1:00:52
  show about some lost advanced ice age civilizations or something. To what do you attribute this
• 1:00:59
  proliferation of this type of junk?
• 1:01:02
  Well, I think they tell very simple stories sometimes when the reality is much more complicated.
• 1:01:11
  They appeal to the unknown, the fact that there are gaps in our evidence. And so, you
• 1:01:16
  know, these people fill in those gaps with their own crazy theories. And there's also
• 1:01:23
  a kind of, yeah, there's maybe an anti-science agenda, an anti-expert agenda. Here's kind
• 1:01:29
  of someone who's self-taught, you know, they've learnt this themselves. The knowledge has
• 1:01:35
  not been handed down to them. You know, they've learnt it themselves and they're up against
• 1:01:39
  these experts. You know, they're pioneering a different way of thinking and these experts
• 1:01:44
  are kind of the conservative reactionary forces shutting down these alternative views. So
• 1:01:51
  maybe there's an anti-science agenda in there even. But it was good that, you know, if people
• 1:01:56
  listening to this get a chance to view the Joe Rogan debate between Flint Dibble and
• 1:02:02
  Graham Hancock.
• 1:02:03
  Yeah, I've just seen that.
• 1:02:04
  I mean, there's hours of it, but it really is. If you've got the stamina, these are great
• 1:02:09
  to watch because in the end, Graham Hancock admits that he doesn't have any direct evidence
• 1:02:15
  for the existence of his ancient civilization that he claims was behind all this spread
• 1:02:21
  of knowledge 10,000 years ago.
• 1:02:24
  But the comments are still kind of dispiriting and depressing under the video. They're like
• 1:02:29
  people are still accusing the archaeologist Flint Dibble that he's being arrogant and
• 1:02:35
  that he's laughing when Graham Hancock-
• 1:02:37
  I mean, we get the same thing from creationists. You know, I got involved with public debates
• 1:02:42
  with the creationists, the top creationists 30 years ago in London. It's the same sort
• 1:02:45
  of attack on knowledge. You know, people claim that, you know, debate is being shut down
• 1:02:53
  and it's like climate change debate. You know, 99.99% of the evidence shows that the Earth's
• 1:02:58
  climate is changing in the direction predicted by climate change experts. And yet there's
• 1:03:03
  still people who will say it's a conspiracy. They're making it up. They're twisting the
• 1:03:08
  evidence. The Earth is not getting warmer. Or if it is, it's just natural processes,
• 1:03:13
  which is, you know, it's true. Climate change is happening all the time. In the Earth's
• 1:03:16
  past, it's happened all the time. But what's happening now is exceptional and it seems
• 1:03:22
  to be linked with our behavior.
• 1:03:23
  Why do you think so many people are more convinced we are a product of breeding with aliens with
• 1:03:28
  like zero evidence than in evolution with plenty of evidence? Are we just like ashamed
• 1:03:33
  of our lowly origins, as people used to say?
• 1:03:36
  Yeah, it's difficult to understand. It's also difficult to understand creationists. You
• 1:03:40
  know, you're dealing with a completely different mindset. And it's difficult to get inside
• 1:03:44
  the heads of these people and how they think. I think if we go into it with an open mind,
• 1:03:51
  and you know, I've had to change my mind about a lot of things along the way. And it's
• 1:03:54
  been better for me to do that. And the good thing is, you know, I've changed my mind about
• 1:03:58
  homo hydrobergensis being our ancestor. You know, 20 years ago, if you'd asked me about
• 1:04:03
  the animal breeding, I'd have said, well, if it happened, it was trivial, and we'd not
• 1:04:07
  find any evidence of it today. And I was wrong. And I've had to admit I was wrong about that.
• 1:04:12
  And once you've admitted you're wrong about something, it's actually easier to admit the
• 1:04:14
  next time that you've been wrong about something. And I think everyone should be able to question
• 1:04:19
  their own beliefs, as well as other people's beliefs. And I think that's what these people
• 1:04:23
  lack. They lack a self critical judgment to actually criticize, look critically at their
• 1:04:29
  own beliefs, as well as that of the other people they don't agree with.
• 1:04:34
  What's the quickest way to disarm people who don't believe in evolution in 2024?
• 1:04:39
  Well depends on how much time you've got. But you know, I think, you know, if you show
• 1:04:44
  them the skeleton of a chimpanzee, strip bear and the skeleton of a human, and we've got
• 1:04:49
  an example in our human evolution exhibit in London, we've got a chimpanzee skeleton
• 1:04:53
  there in the same display case as a homo sapiens skeleton. And every element of the skeleton
• 1:04:59
  is the same. They're differently shaped in proportion because of the different ways of
• 1:05:03
  life and adaptations and evolution. You know, these have been separated by maybe 7 million
• 1:05:08
  years, but the similarities are striking. And even the people who didn't believe in
• 1:05:13
  evolution 150 years ago, people like Owen, who founded the Natural History Museum, he
• 1:05:19
  couldn't deny the major structural similarities that were there. Okay, he thought God was
• 1:05:23
  behind this design. But you know, those structural similarities are there, regardless. And there's
• 1:05:30
  all the genetic data too, of course. So it depends how much time you've got. But I would
• 1:05:34
  say just as a striking thing, just look at a chimpanzee skeleton and compare it with
• 1:05:38
  a human skeleton and say, you know, are these similar or not? And maybe for comparison,
• 1:05:44
  have a dog skeleton or a horse skeleton next to it and say, how similar are these compared
• 1:05:48
  with that? What do you think is behind this last question, this anti science agenda lately,
• 1:05:54
  because when I was growing up, people wouldn't say this stuff out loud, maybe they were thinking
• 1:05:58
  it, but kind of people would be a little bit embarrassed or ashamed to make these sort
• 1:06:03
  of crazy sweeping claims without any... I don't want to implicate you in this, but
• 1:06:10
  podcasts, the fact that social media is now so much part of it. I mean, there weren't
• 1:06:16
  all these different ways of transmitting all these crazy theories now. But anyone now can
• 1:06:21
  set up their own account, website, podcast, whatever, to proliferate these crazy ideas.
• 1:06:29
  And they have a life of their own. We see the way that as you've said, you've looked
• 1:06:32
  at the commentaries on the Graham Hancock debate. You know, these things can just take
• 1:06:38
  off and I suffer it too. I get plenty of abuse on social media too. It comes with it and
• 1:06:45
  you have to just develop a thick skin, unfortunately, as a scientist. You're accused of all kinds
• 1:06:50
  of conspiracies and it's sad.
• 1:06:53
  Such as?
• 1:06:54
  Well, I'm hiding evidence. The museum is hiding evidence. The creation is accusers of that.
• 1:07:00
  We're hiding evidence that disproves evolution. We only put out the evidence that suits us.
• 1:07:05
  There's a famous example with the creationist. I don't know how much time we've got now,
• 1:07:10
  but there's Guadeloupe in the West Indies, the island of Guadeloupe. A skeleton was found
• 1:07:16
  there in the early 1800s by the French and it was completely encased in a rocky sand,
• 1:07:25
  so beach rock we can call it. But it was obviously a homosapien skeleton encased in beach rock
• 1:07:31
  and it was taken as a curiosity because it seemed to be like a fossilized human skeleton
• 1:07:35
  in rock. So the French took it and this was the Napoleonic Wars and so then the ship that
• 1:07:42
  was carrying it got captured by a British ship. And so they found this giant, this skeleton
• 1:07:47
  in beach rock from Guadeloupe and it ended up in the British Museum and now it's ended
• 1:07:52
  up in our museum. And it was on display for many years as an example of rapid fossilization
• 1:07:59
  of a human skeleton. But no one thought it was very old because that beach rock contains
• 1:08:05
  charcoal and pottery and things like that. So it was known to be recent, but a creationist
• 1:08:11
  got hold of this story and said the museum had this example actually of a victim of Noah's
• 1:08:17
  flood. So this skeleton was actually buried during the time of the flood. It was fossilized
• 1:08:25
  by the weight of the thick flood waters and these rocks are mycene in age. So this in
• 1:08:31
  geological terms this is a very ancient body and the museum has taken it off display and
• 1:08:36
  is hiding it as an example because it's proof of Noah's flood. I mean it seems crazy to
• 1:08:41
  us but that's what they published and I had to deal with this for years afterwards. I
• 1:08:46
  still do have to deal with it now and again of people claiming we've hidden a skeleton
• 1:08:50
  that proves Noah's flood. This was a victim of Noah's flood. I mean it's laughable but
• 1:08:58
  I have a thick stack of correspondence. I had to write papers refuting this story believe
• 1:09:03
  it or not. There we are. Yeah. Well I'm not sure if I should laugh or cry about this.
• 1:09:11
  It's certainly amusing but I know that if you're spending decades on actual research
• 1:09:16
  into human origins it stops being amusing at a certain point. Yeah I have to laugh at
• 1:09:20
  it now but it wasn't funny at the time when it started. Right. Professor thank you so
• 1:09:26
  much for taking the time yet again. Really appreciate it. Are you still active on Twitter?
• 1:09:31
  Where can people find you? Yes I'm active on Twitter and yeah there's this Neanderthal
• 1:09:35
  documentary on Netflix today so I may be commenting on that later on too about Shenadar. Oh perfect.
• 1:09:42
  So this what's it called? I can't even remember the title that's a shame. Secrets of the Neanderthals
• 1:09:49
  yes but it focuses on new discoveries from Shenadar cave. A new Neanderthal partial skeleton
• 1:09:57
  with a face and they've got a fantastic reconstruction of this Neanderthal woman that lived maybe
• 1:10:02
  75,000 years ago. So that's on Netflix today. Fantastic. I'll no doubt be commenting on
• 1:10:07
  that it's shown later on today. Alright perfect. So Netflix has done something to kind of recalibrate
• 1:10:14
  after that Graham Hancock. Yes and even the cave of bones the Homo naledi story which
• 1:10:20
  we haven't got time to talk about again now but you know the claims by Lee Berger that
• 1:10:24
  Homo naledi was making art and burying its dead and making fires in the cave that was
• 1:10:30
  another Netflix documentary that wasn't Netflix's finest hour. Okay thanks again professor.
• 1:10:38
  Always a pleasure. Thank you. Good to speak to you. Thank you so much for listening. If
• 1:10:42
  you liked what you heard please consider subscribing to Smart Cookies on YouTube. What else is there?
• 1:10:49
  Apple podcasts and Spotify and if you really like what you heard feel free to become my
• 1:10:54
  Patreon. No my Patreon on Patreon by going to Patreon and becoming my Patreon it's really
• 1:11:00
  easy just type Smart Cookies podcast in there. You should be able to find me. Last but not
• 1:11:05
  least I have to thank the absolute legends that are my producers on this show. My existing
• 1:11:12
  patrons on Patreon, Ida, Mansihan, Micheal Medved, Medinio, Gordon, Yurichuk, Lorenzo,
• 1:11:20
  Mila, Carmen, Tai Chi, Gordon and Veronica. Without you guys this show wouldn't exist.
• 1:11:27
  So massive thanks and yeah see you in the next episode. Bye.