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Human Origins with Chris Stringer · The Smart Cookies podcast

• zaza: professor chris stringer was a graduate of UCL and has worked at the natural history museum london since nineteen seventy three he is chris_stringer: oh zaza: now research leader in human origins and a fellow of the royal society and is also a visiting professor at royal holloway and u c l his early research was on the relationship of neander tolls early modern humans in europe but through his work on the recent african origin theory of modern human origins he now collaborates with archaeologists dating specialists and naticists chris_stringer: uh zaza: in attempting to reconstruct the evolution of modern humans globally he has published over two hundred and fifty chris_stringer: yeah zaza: scientific chris_stringer: m zaza: papers his recent books include the complet world of human evolution the origin of our species and britain one million years of the human story who professor stringer welcome to europe trash chris_stringer: thank you for having me zaza: preparing for this interview i read your wonderful column in the guardian it's called out of africa my lifelong mission to trace the origins of humanity in it you write about how you became an anthropologist dedicated to exploring our origins but you also describe your first research trip that took that you took in the seventh is to study neander specimens i believe right in the chris_stringer: that's zaza: article chris_stringer: true zaza: there's a cool picture of iou drying your clothes beside your car somewhere in ugaslavia which is the country chris_stringer: yeah zaza: where i was born chris_stringer: uh zaza: about a decade later chris_stringer: oh zaza: so i was chris_stringer: yeah zaza: thinking before we go on to discuss hominins could you chris_stringer: yeah zaza: perhaps talk a little bit about your adventures in eastern europe because apparently chris_stringer: oh zaza: there were quite a few chris_stringer: yeah so this trip nineteen seventy one of course then we were in the soviet era zaza: yep chris_stringer: so things were very different in eastern europe and i took myself on a trip around over a dozen european countries with my old car zaza: ah chris_stringer: lasted five months i did about five thousand miles zaza: whoa chris_stringer: so that's eight thousand kilometers and uh yeah it was for someone who hardly left britain and really had only minimal french as any foreign language it was zaza: yeah chris_stringer: it was quite a challenge is something i would never even think about if i think back now i don't know how the courage of youth foolishness of youth that attempted to do it it seemed zaza: yeah chris_stringer: looking back it was crazy it worked as well as it did so yeah so i wrote ahead to all these museums across europe including in eastern europe for permission to stay their fossils of early homosapians and the oudertols and any other interesting fossils they had that were relevant and many of them answered back quite politely some said e couldn't care and so i planned the trip accordingly and yeah so i was going zaza: what chris_stringer: i abandoned going into east germany there was no co operation there but zaza: m chris_stringer: checkers of aca as was then i entered there and unfortunately the date of entry was very unlike it was the third anniversary of the soviet invasion zaza: yeah chris_stringer: of checkers a vaca so this was a very tense day to be there anyway zaza: yeah chris_stringer: and i turned up in my zaza: yeah chris_stringer: old car with my long hair and beard and zaza: yeah chris_stringer: looking probably not very tidy zaza: yeah chris_stringer: on my old car and these border guards and checks of ak obviously they love papers and my passport and they said you can't come in and i showed them the letter from the national museum in prague and from the anthropology museum in bruno and they said they looked at these and said your visit is of no benefit to the people of checkers of zaza: oh chris_stringer: so that was it and they also had got me to unpack my whole car so they wanted everything unpacked so i had strewn the whole contents of the car all over the road and they just said no you can't come in sorry that's it and they just left me there to repack my car so i had to pick up all this stuff and i was repacking it thinking well you know that's that's a week gone out of my sherdule now when i'm not going to be there and all the other dates will be out of sequence because so i was pretty despondent and i nearly finished repacking and meanwhile they were watching some european football game on their tiny zaza: oh chris_stringer: little black and white television in the border post zaza: yeah chris_stringer: and then they kind of came out and said with my passport and they said okay we changed our mind you look like comrade cha zaza: yeah chris_stringer: so we're going to let you in so because zaza: yeah chris_stringer: they said i looked like vara somehow this random thing i got in checifcsode zaza: m chris_stringer: i was able to study the fosses there and that was great and then i went through into austria and eventually came into what was the new slavia zaza: ah chris_stringer: and headed to the national museum in a rib as it was and there there had been this zaza: yeah chris_stringer: really prominent anthropologist in the early nineteen hundanovitch cranboga and he was the guy who had described these wonderful neamdetolfossals from a syce called rapine spelt with a k rapin rapine maybe i pronounce it wrongly you can correct me zaza: oh good chris_stringer: anyway zaza: no really good chris_stringer: so and the incredible thing was that his office had been preserved like a kind of museum from those early nineteen hundred zaza: oh chris_stringer: so unfortunate the director of the museum wasn't there so his assistant looked at zaza: yeah chris_stringer: the letter and said okay you can come in and you're one of the very zaza: oh chris_stringer: few people allowed to study these fossils they hardly studied so they took me into his zaza: yeah chris_stringer: office which was beautiful there from the nineteen hundreds and they brought in these old wooden boxes zaza: oh chris_stringer: with the crap an fossils and you know i started to unpack and zaza: a chris_stringer: measure them and the sad thing was that i had an unfortunate accident with one of the fossils so one of the most well zaza: ye chris_stringer: preserved fossils which was a face and the scale of one audetomcrap in the sea zaza: did you drop it chris_stringer: well i didn't drop it it was nearly as bad zaza: okay chris_stringer: so for my measurements i had to put these instruments on various points zaza: yeah chris_stringer: to measure the dimensions of the fossil and i had calipers that were but sharp and when i put them into this position on the skull and i got you here's a mandate skull here zaza: oh chris_stringer: i can show you zaza: awesome chris_stringer: exactly zaza: yes chris_stringer: what i was doing he's a replica and fusel here so let me just put my head thrown back in zaza: yeah chris_stringer: yeah so yeah so i put the canopus here and here to measure across the breadth of the orbits and the face just fell off with a clank on to the desk zaza: the jaw just fell off chris_stringer: the whole whole face separated here and here and fell on to the zaza: a chris_stringer: desk separate from zaza: were chris_stringer: the skull zaza: you alone in the room chris_stringer: uh zaza: or chris_stringer: yeah zaza: was somebody chris_stringer: i had zaza: supervising chris_stringer: my zaza: you chris_stringer: my my then girl friend was with me and we were just horrified zaza: oh chris_stringer: so the thing had fallen apart and there were these old glue joints probably animal glue from the nineteen from nineteen ten or something and they become very dry so putting the calopsin here the thing just separated with a clank into two pieces and zaza: ye chris_stringer: i was just this was this precious fossil zaza: oh chris_stringer: so you know what do we do and i didn't have any glue with me otherwise i would have fixed it then and tried to pretend nothing had happened so i had to go to this poor curator zaza: oh chris_stringer: assistant curator and tell him what had happened he could see his his own career rect zaza: yeah chris_stringer: let me get this precious forces zaza: oh chris_stringer: had this accident so we said to him look you know if we can find some glue we make we could probably fix it it would look as good as new zaza: yeah chris_stringer: so that's what happened so we went out we got some zaza: m oh chris_stringer: good ucaslaviand glue zaza: yeah chris_stringer: and we glue the pieces back together again and all was well zaza: yeah chris_stringer: and he was relieved and we said we won't tell anyone you know this is it's all fine and zaza: yeah chris_stringer: the interesting thing is i don't know probably maybe five years later another colleague i knew who was going to rap and he went there five years later to study the same fossils and when he came back i met him and he said had this terrible story said i said he said well some zaza: m chris_stringer: student broke the zaza: oh chris_stringer: crap of the c fossil and they had to get together again i said that's terrible it's terrible any zaza: oh chris_stringer: idea who it was he said yeah pparently some zaza: ye chris_stringer: american student zaza: oh chris_stringer: i was so relieved at that point you know zaza: yeah chris_stringer: so yeah now you know truth about that one zaza: yeah chris_stringer: so yeah zaza: yeah chris_stringer: so zaza: oh chris_stringer: yeah a lot of adventures i got robbed in rome and robbed again and having your onset stuff and stuff ended up just with the dirty washing that they left my laundry bag to wear for the for the last three weeks of my trip but yeah i managed to gather data on on most of the forces i wanted to study and then i came back to bristol which is where i was doing my ph d to actually start putting the data together and it was testing whether neadetols made good ancestors for hormosapens which was the leading idea at the time zaza: i'm surprised they let other foreigners in after your chris_stringer: yes zaza: mishap chris_stringer: well that's right yes yes indeed yeah yeah zaza: that's awesome all right we were always chris_stringer: yeah zaza: kind of led to believe that the evolution of ancient humans progressed in a kind of a liner fashion chris_stringer: oh zaza: you know that we went from the early i don't know let's say homohobilist the so called handy man right to modern humans in a continuous fashion almost like in a straight line chris_stringer: oh zaza: when the new commune species evolved from the previous one that's what they told us um you know they took over and that was that however this picture has been turned on its head and we know that there were many different chris_stringer: oh zaza: hominis is it hominis or hominis chris_stringer: yes coming in coming zaza: hominanc chris_stringer: in for us and our zaza: yeah chris_stringer: closest relatives yet zaza: right they were living chris_stringer: yeah zaza: on earth at the same time all of these different hominis right chris_stringer: yeah zaza: it was chris_stringer: this zaza: also chris_stringer: is the amazing zaza: simple chris_stringer: thing zaza: once what happened chris_stringer: yeah so even seventy thousand years ago which is like yesterday geologically speaking there were at least five kinds of humans around on the earth so we had been evolving in africa homosapiens the neandetols have been evolving in europe and asia over in eastern asia there are these denicivents that we learned about zaza: yeah chris_stringer: in the last ten years or so zaza: oh chris_stringer: and on the islands of south east asia there's this a little dwarf species called homoforesiencis zaza: the hobbit chris_stringer: so called zaza: right chris_stringer: the hobby and homolusidenis on the philippizes so there are at least five kinds of humans around possibly there were more in africa that don't know much about even then and now we're the only one so within another forty thousand years all those others have gone as far as we know and there was just us zaza: that's chris_stringer: so that's zaza: so chris_stringer: one zaza: trippyyeah chris_stringer: of the big outstanding questions is what happened to those other species were we involved in their disappearance or did they die out for other reasons so that is one of the big questions and the interesting thing is if we go further back in time that pattern of diversity is there right through human evolution is like nature is almost experimenting in how to make a human and there are all these different lineages and the rest of them end up going extinct at least physically extinct obviously we can come under the question of the fact that even the out of times and dnitevents haven't totally disappeared because of course before they disappeared they enter bread with our ancestors and so you and i are partly in the dato we have a bit of the gens from their inter breeding maybe fifty thousand years ago so yeah things are much more complex when i did my ph d yah you're right it was these were these very simple stories of single lines of evolution zaza: yeah chris_stringer: one stage leads them to another and it's a kind of progression towards our wonderful species omosappens and we know it certainly wasn't a linear progression it was complicated and even our coca success now if you can call it that zaza: oh chris_stringer: change zaza: oh chris_stringer: a few parameters and we probably wouldn't be here now maybe in the outer tales would have carried on the story who knows zaza: that's fascinating what is the so chris_stringer: yeah zaza: called out of africa theory that you've been chris_stringer: yeah zaza: researching chris_stringer: yeah so in fact there were a number of out of africa to africa because it was the largest inhabitant continent it's been very important in human evolution so africa seems to be like a laboratory that creates species and some of them left africa so probably the first five million years or so of human evolution as far as we know took place only in africa so the split from him pansies closest living relatives almost certainly in africa and then we had these lines of evolution because the chimpanzes must have had lines of evolution to about which we know very little but we have these creatures which are on the human line and by the time we get to about two million years ago there's a species called homo rectus and that species is the first zaza: m chris_stringer: one that we know for sure that left africa and it spreads into asia probably into europe zaza: yeah chris_stringer: soon after that as well zaza: oh chris_stringer: down into right across asia and into south east asia so we find home rectors fossils in africa in western asia over in china down in java in indonesia so that species that's like what's zaza: yeah chris_stringer: called out a gal one and there probably were more out of africa events after that as species came out be cause it isn't all one way now there probably were some into africa events as well that we don't know much about and then we to the last couple of hundred thousand years zaza: yeah chris_stringer: and homosapians by then has evolved in africa and homosapians also starts to emerge from africa so that's the out of africa theory that people sally think of the spread of homosapians from its african homeland the rest of the world so that's the one that i've probably you know helped in developing this idea that we did have a recent african origin and there are other ideas still around to some people subscribe to multireginal model which suggests that actually home rectors did not die out in other regions even in in europe in africa in china in java in all those areas homeware erects carried on evolving towards thomas appens and on that view we can trace let's say the origin of native australians back to over a million years ago java and we can trace the evolution of recent asian people like chinese people their ancestors go back to home rectors in china a million years ago zaza: m chris_stringer: the ancestors of omasappians in europe were in europe a million years ago and african ancestors were in africa a million years ago so that's the multi region model that's kind of one extreme we've got the recent african origin model that says actually there was only one place where there was a line of evolution from early humans through tohomosapians that was in africa and then we came out and we as we've said somehow we replaced these other species outside of africa that it evolved outside of africa and that's the classic out of africa theory and it suggests that the regional variation we find today in europe in china in in australia africa that's a recent recently evolved thing so a hundred let's say two hundred thousand years ago there were zaza: m chris_stringer: none of these regional variants of homosapians that we find today they are recently evolved mostly most of our regional features that characterize people today have evolved in the last fifty thousand years zaza: this is going chris_stringer: yeah zaza: to be a bit of a stupid question but i'm going all in here i'm sure i'm sure i'm not the only person who's wondering this what does an evolutionary jump in humans like look like is there chris_stringer: yeah zaza: is there suddenly a whole generation of babies being born that just look different and are clearly a new species or does it happen sort chris_stringer: oh zaza: of gradually bit by bit with new physic attributes chris_stringer: yeah zaza: slowly chris_stringer: yeah zaza: emerging i have i've always chris_stringer: yeah zaza: wondered this chris_stringer: the zaza: i chris_stringer: record zaza: blame the education system for making these things chris_stringer: ye zaza: so abstract chris_stringer: sure yes so i mean some evolutionary changes if we look at the bigger picture can occur very rapidly but in humans as far you know from the fossil record most of these changes look fairly gradual so if we look at the african record of homo sapiens evolution we have fossils three hundred thousand years old show a few features that would characterize homosins today so i've got a skull here which zaza: nice chris_stringer: you know we can say this is this is a homosapian zaza: m chris_stringer: repture of homosapins zaza: yeah chris_stringer: fussleon zaza: yeah chris_stringer: so we're characterized by this high and rounded brain case and small brow ridges at the front small face zaza: i chris_stringer: that's tucked under the brain case if we had the lower jaw there'd be a nice chin zaza: yeah chris_stringer: on the lower jaw our ear bones if we had ctscans we could see inside the ears and the little ear bones inside are also distinctive in homsapians and we look at our skeleton a skeleton did lightly with a narrow rib cage a narrow pelvis and so on so those features characterize thomas zaza: oh chris_stringer: appian and if we look at the evolution in africa the interesting thing is zaza: oh chris_stringer: that there are some fossils as i say three hundred zaza: yeah chris_stringer: thousand years that have some of those features but not all of them and when we get to about two hundred thousand years we start see fossils that show most of those characters and one of the uncertainties at the moment is those features evolve zaza: my chris_stringer: fairly suddenly zaza: oh chris_stringer: in one group or did they evolve gradually over a long period of time and unfortuatly the african fossil record is not complete enough and it's not well dated enough to answer that question so mostly evolution seems in humans seems to go gradually so the evolution of the neandatoles in europe and asia seems to if we look at the fossil record seems to show zaza: yeah chris_stringer: a gradual build up features for home sapiens the record in africa is not good enough to really see zaza: hm chris_stringer: if that's the process that's zaza: right chris_stringer: going on certainly it's a long process zaza: oh chris_stringer: our evolution in africa took probably half a million years so that's a long time the neander told all be evolved over the same time scale and people over in asia in eastern asia probably there's a separate line of evolution there over the same time scale and homo rectus carried on evolving indonesia for probably over a million years zaza: all chris_stringer: so zaza: right chris_stringer: these zaza: another chris_stringer: are zaza: another chris_stringer: long stories zaza: right another naive question chris_stringer: yeah zaza: we're all we're in all shapes and sizes homeless apiens i walked down the street chris_stringer: oh zaza: here in berlin you know tall people short people whatever different features chris_stringer: yeah zaza: how do we know once we find chris_stringer: oh zaza: a skeleton or something that it's not just a funny looking homo sapiens that it's a different chris_stringer: yeah that's zaza: species chris_stringer: a very good question and zaza: yeah chris_stringer: we talked about home flresiensis this habit on on the island zaza: yeah chris_stringer: of florida and an easier some people maybe even today there are some people that still think it's some weird variant of homosapians they think that it's probably homosapians with some disease that zaza: yeah chris_stringer: made it very small and small brained so yeah it it is a good question how do we these are different species and for me the measure of variation zaza: yeah chris_stringer: that we find in primates today is the guide so we have zaza: a chris_stringer: to look at variation in chimpanzskeletons gorilla skeletons in skeletons of baboons that are different species that they we look at them in nature we see that they're distinct they have distinctly evolutionary histories we regard them as distinct species so that's the measure that we try and use when we look at zaza: yeah chris_stringer: the fossils so that was what for my ph d i had a a data base of hundreds of scales of modern humans from around the world from australia from zaza: hm chris_stringer: china from europe from africa and i use that as my base line if you like tell me what a homosapian should be and i could find fossils fifty thousand years ago and a hundred thousand years ago that fitted that categorization so there were some in israel which we zaza: m chris_stringer: now know ere a hundred thousand years old those fitted my characterization of homosapians based on the variation today but when we came to zaza: yeah chris_stringer: ned as they were like two zaza: oh chris_stringer: or three times as different as that zaza: m chris_stringer: variation we find today so for me that put them outside of homosapians zaza: okay but i chris_stringer: uh zaza: read chris_stringer: and zaza: somewhere chris_stringer: home rectus zaza: yeah chris_stringer: was even further away zaza: okay chris_stringer: so yeah zaza: yeah chris_stringer: so it's a relative thing and it's a judgment zaza: oh chris_stringer: of course because we don't know for sure and then maybe like you at school i was told that species are characterized zaza: oh chris_stringer: by not interbreeding with each other so that was this is the so call biological species concept species are reproductive isolated they don't interbreed with each other so of course if you apply that to the fossils as i've said we now know that you and i have not and in go so we interet tis so on that basis they should be the same species as us but of course that's where the species concept gets complicated because you know nature we create these species concepts and nature doesn't play along with them you know we humans are great classifiers we like to keep things simple and in clare or is but when you look at jackals and wolves when you look at polar bears and brown bears they are good species apparently but when you look at their genus they do a bit to breeding in africa there are a number of baboon species they look like good species they behave like good species that have different diets different coloration you can zaza: yeah chris_stringer: distinguish the skeleton when you look at the d n they do a bit zaza: oh chris_stringer: of inter breeding so this is it that takes a long time in many cases zaza: m chris_stringer: in mammals and birds in particular for these species to become reproductively isolated one two million years probably so we've been separate from the neadatols maybe six hundred thousand years perhaps similar to polar bears and brown bears so hybridization into breeding was still possible and the interesting thing is we can see from the inter breeding that happened in the end of tales that actually there were even some benefits for that interbreeding we picked up things from the neaditos that were useful to us fifty thousand years ago so we had evolved in africa and then we came into these new environments in europe and asia and we didn't have immunity to the local diseases the path agens the parasites the neandatols zaza: oh chris_stringer: had evolved some of those immunities so by interbreeding with them we got a quick fix to our immune systems that was good news fifty thousand years ago medically not so good news now because it seems that some of those immune system that zaza: ye chris_stringer: we picked up from the udotoles are causing auto immune diseases in humans today zaza: oh no okay chris_stringer: yeah zaza: because i've read a really silly bizarre article about as osborne the famous rock star chris_stringer: yes zaza: apparently he did some genetic testing and they said that one of his neandertel gens heal him survive drinking four letters of konak a day does that make any sense chris_stringer: well zaza: whatsoever chris_stringer: there you are yeah so yes i mean there are there are nandetlgns which in homasappyand seem to be linked with addictive behaviors so this is very strange if you look at modern genus and you look at modern characteristics if you have big enough samples tens of thousands even millions of gems and you look at the behavior record you can make correlations between bits of d n a and bits of modern behavior so there are bits of d n in the modern geno that have at least a slightly higher percentage of meaning that you are addicted to smoking you can't give up smoking easily if you've got certain bits of d n a and the weird thing is when you zaza: yeah chris_stringer: met where the neaditoldn is in our gobs some of it comes up in those places so the suggestion is that if you've got certain bits of neaditoldna you're going to find it harder to give smoking you have some addictive traits in your personality now that's weird because there was no tobacco around zaza: yeah i was chris_stringer: when zaza: just chris_stringer: the zaza: about chris_stringer: editors zaza: to ask chris_stringer: are zaza: where chris_stringer: around zaza: they like chris_stringer: they zaza: smoking chris_stringer: weren't smoking tobacco because zaza: ah chris_stringer: it came from the new world zaza: okay yeah of course chris_stringer: so it probably tells us is that there's something in the audotldn that zaza: yah chris_stringer: encourages repetitive zaza: ah chris_stringer: behavior zaza: oh chris_stringer: and that may be good news may be you know fifty thousand thousand years ago if you were going to make fire which is very adaptive and useful you have to be very persistent to keep going until you made the fire so it could be something like that it might also be that a slight mis match between that bit of d and our genes because of course that bit of d n a and the i was part of an told you know put it into our gun which is slightly different gens don't work in isolation so it might be that that that bit of dan just doesn't work in our go the way it worked in the nditogunow so this is all fascinating medically important we know that there are bits of and that give some immunities against covid and other bits which actually make people more susceptible to having clovid zaza: m chris_stringer: again this doesn't been the advertise where dealing zaza: m chris_stringer: with covid but they were dealing with other diseases we've got bits of their immune systems it kind of swings around about some bits of d and good some bits of bad there's also some bits of new and n that seem to be correlated with in modern humans with strokes with rombosis zaza: m chris_stringer: and it's possible that the tales had bits of d n a which encourage the blood to heal quicker zaza: yeah chris_stringer: because life is dangerous in the end of our times you're using sharp flint tools you're dealing with your zaza: m chris_stringer: in with dangerous animals you're giving birth to children without a medical support so it may be that they had bits of dan that encouraged the blood to clot quicker that was good news fifty thousand years ago and we picked it up from them for the inter breeding but today with our life styles it actually seems to be linked with a higher risk of strokes so yeah this is really fascinating stuff and it is something that's only really becoming cool in the last ten years with this knowledge of the new detonite breeding and equally denise inter breeding we haven't got to denismetyet but that also is going to be important medically as well zaza: so we also have some denison dan n chris_stringer: well many people do yeh so the dindesvens lived over in the far east and we think they probably also lived down in south east asia so they are known from of course their primary site of denise in siberia and russian archiologies have been digging that site for more than fifty years and they found fragmentary human fossils impossible to tell what species they were although there were some very big teeth and when the d n was tested about twelve years ago scientists found that there was a whole if you preserved in a little finger bone fragment and it wasn't the end of time it wasn't homosapians it was something different and we call that different thing denicimant and we now know that to the denicmans lived in de net cave probably for a couple of hundred thousand years they were there a long term we've even got the d n and the sediments of the cave so we don't even need their fossils even from the sediment of the we have the d n telling us they were there for a long time neander zaza: yeah chris_stringer: tolls were there some of the time as well and we even have a girl a tiny fragment of bone which is from a girl who lived there zaza: m chris_stringer: maybe a hundred thousand years ago and her mother was in the amdetol and her father was denise zaza: m chris_stringer: she looks like a first generation hybrid so not only were we reading mnatatols but zaza: wow chris_stringer: atisodes and denicimens are interbreeding with each other and when we look where denison dan is today just as we can find the ndatldand pretty well everyone outside of africa at about two per cent there are populations today that have denicandna eastern asians native americans have some but the largest amounts are found in places like the philippines paper new guinea austra ali and that suggests since those the ancestors of those people as far as we know never went anywhere near siberia it means that there were denicimenlike people zaza: oh chris_stringer: living in south east asia fifty three years ago when homosapians populations came out of africa and went through that region they interpret with denisevens and picked up some of their d n a and so those populations if you like have a double dose of intrigress d n they have d n a from neander tales and then added on top of that there's dan from denisivanlike populations so it's a complicated zaza: oh chris_stringer: story the denicivents we know physically not much about them we know we've got the whole genus but there is a jaw bone from the tibetan platter of china over a hundred and fifty thousand years old from j is thought to be denise based on a little bit of protein material extracted from it and there are passes in china m one from darley and when i was involved in studying from harbin so called dragon man beautiful fossil over a hundred and fifty thousand years old we don't have its d n a it's obviously a distinct kind of human it's not the tan not cosappyand zaza: ye chris_stringer: it's not homewaerectrs so it's possible that that too is a new seven and hopefully one day we will have a really complete hustle with a complete geno zaza: m chris_stringer: and we can really tell who these denismons were but it's likely they are a third lineage so there was a split maybe six hundred thousand years ago the denise the new editors and us yeah zaza: that's such a wild world that we were sharing the planet with four other at least for other homini chris_stringer: yeah zaza: species chris_stringer: absolutely yeah zaza: were we for how long did we share the planet with these other chris_stringer: well zaza: species for chris_stringer: we co evolved with those lineages as i say probably for five hundred thousand years it's likely that the zaza: oh chris_stringer: florzienes lineage and they lose an incest need to go back on those islands much further they may go back a million years and in the last five hundred thousand years yes we had evolved the new andetiles had evolved at zaza: m chris_stringer: the beginning their evolution and the denicimans must have begun their olution as well probably in the last four hundred thousand years at least zaza: so chris_stringer: so zaza: were chris_stringer: yeah zaza: we competing with these different species chris_stringer: not in zaza: or chris_stringer: the same areas obviously the evolution of these populations for them to develop enough separate features they were geographically separate and reproductively separate that zaza: right chris_stringer: they could build up their own separate features so that was the story most of the time now and again they did come together and so there's evidence in europe from over two hundred thousand years ago that there was some kind of interbreeding event between early shomosappiand early and tales because the interesting thing is if you look at the whole geno of neandetol and ence scientists calculate that they separated may be as say six hundred thousand years ago but if you look at the mitoqondrial d n which is one tiny bit of d n that's inherited from mothers to daughters separately if you look at that the coalescence date as in the andtoles is only about three hundred fifty four hundred thousand years and if you look at the micromsone which is passed on through mails from fathers to sons if you look at that again the coalescence date when we had a common ancestor is around four hundred thousand years so that suggests that there was mixture maybe three or four hundred thousand years ago between early homosapians and early eandetols and that led to intermixture and the on was actually acquired o sapiens the midecondyo and the licramdou so zaza: m chris_stringer: that's an interbreeding event zaza: m chris_stringer: that we know very little about there is what looks like a homosappins possibly in greece from over two hundred thousand years ago from a site called apidemcave and i was involved in studying this with katerina havartyand colleagues this back of a skull in a pidemccave is dated over two hundred thousand years and it looks cohomosapians fossil from the back of the skull now it is only the back of the skull we haven't got the whole skeleton just the back of the skull but it looks like a hormosapiens that could present one of these populations came out in a very poorly known dispersal from africa more than two hundred thousand years ago mixed with some new and then disappeared and so that's the interesting thing is we we've talk about the replacement of the anvetols but it looks like at times you had the reverse process the abits actually replace thomas appens at times outside of europe so outside of africa so this success of homasappians in the last fifty thousand years we can call it that it wasn't pre ordained and there were times in the past when the andatisit looks like actually replace thomas appian in some locations zaza: whoa now when chris_stringer: yeah zaza: the nisofan and neandertall met each other let's say would they know that they're chris_stringer: oh zaza: different not chris_stringer: ah zaza: really chris_stringer: well they would have looked they would have looked different certainly we know from the available data that they were different so the teeth size is very different in this one he got very big teeth compared with us and then he had old and their geno suggest that they separated off from neandetoas more than four hundred thousand years ago so they would have looked different obviously if some of these chinese fuss are genies yeah they would have looked quite different so the harbin fuss if that was a denise what it tells us is yes the denison were large and they were very large bodied they had strong brows like a nealiton and a long low skull like a natal but their face looked much much more like our face so the face of the ants is very distinct and we've got that replica in the anatol here again the nantes have got this very big nose zaza: just chris_stringer: in the zaza: a quick chris_stringer: middle zaza: disclaimer chris_stringer: of the face zaza: for those of us who are chris_stringer: yeah zaza: listening to us check out the u tube interview version of the interview as well so you can chris_stringer: yes zaza: see what chris_stringer: sure zaza: professor chris_stringer: anyway zaza: is showing chris_stringer: so nantilshave got a very big nose and the whole mid the face is pulled forwards so whereas in denicivens if this harbonfussl is a denicivan it's got a very flat face it's got delicate cheek bones like a homsapins so we've got a different mix of features zaza: oh chris_stringer: in the harbonfossl so that neadital and the harbin if those people met they would they would look different and obviously genetically separate to so zaza: professor chris_stringer: they had separate zaza: can chris_stringer: evolutionary zaza: you tell from chris_stringer: histories zaza: my face if i have more neandertoldn because i have a really big nose chris_stringer: yeah zaza: does that is that like chris_stringer: yeah well some of us have got big noses as it is yeah zaza: yeah chris_stringer: but the neandetols really did have very big noses and very wide noses so people today you find people with high noses and broad nose a very projecting nose is the new that i has had all three as a unique combination of features so yeah there's nobody today that's got a nose quite like a tea zaza: okay chris_stringer: but yeah zaza: thank chris_stringer: it's zaza: you chris_stringer: an interesting point because people see they've got big brow ridges and i get letters from people in the old days i've got letters now it's emails saying you know i think i've seen in my husband in the tale zaza: oh chris_stringer: you know i think my husband in the anatol ou know he's got great big brow ridges and he's very hairy zaza: yeah chris_stringer: and i think would you like to test d n a i get these kinds of zaza: m chris_stringer: messages zaza: yeah chris_stringer: um but of course zaza: yeah chris_stringer: the zaza: yeah chris_stringer: the physical effects of that d n a are zaza: m chris_stringer: limited we know it's influencing our physiology or mental mun systems that seem to owe something to the d n um but because big brow ridges is not just a tale feature that was a widespread feature and the bridges we have today are not like the anitobrariges or brariges are very modest ard with the veto ones and our noses as they say are only a shadow of what in the amdetolknose would have looked great zaza: right i wanted to send you some of of the hair chris_stringer: yeah zaza: of my friend so you can test it because i'm suspecting chris_stringer: yes zaza: also that they have a lot of nandetldni chris_stringer: yeah yeah but i mean zaza: yes chris_stringer: of the test we've done today on people yeah the variation tends to be around two percent plus or minus maybe half a per cent that's zaza: my chris_stringer: the average i mean there could be people who've got it a little bit more than that and certainly i've mentioned there are people that have got four percent denise so you know that's that's more than we find if zaza: yeah chris_stringer: so the physical physical there could be some effects but the effect seemed to be zaza: my chris_stringer: quite modest at that level of d n a and we know that the d n of neats was selected away quite quickly so we have d n a from early sapiens fosters in europe that are zaza: m chris_stringer: twenty five thousand thirty zaza: oh chris_stringer: thousand thirty five thousand forty thousand years old and within five thousand years of the inter breeding it looks like the new level dropped i'm quite drastically quite quickly a lot of it was selected away but the bits that remain obviously some of that may be chance events but some of it was retained because it would so yeah zaza: how big do we estimate these various populations of homines were i read somewhere that there were only about like twenty chris_stringer: yeah zaza: thousand nandertels on the plan at at any given time this might be wrong but what such chris_stringer: yeah zaza: small numbers chris_stringer: we don't zaza: i guess i never chris_stringer: yeah zaza: understood why we had to compete with each other the earth seems vast with such tiny populations chris_stringer: yeah that's a good point i think that yeah the population numbers we really don't have good data on it genetics estimate population numbers from genetic data and the estimates are that yes and and whole pop tiens could have been down in the thousands or tens of thousands you know maybe a hundred thousand in good times but still very low by modern standards omasappins in africa it's a bigger area more area to inhabit zaza: m chris_stringer: and reasonable environments without the effects of the ice ages that really hit the north population numbers could have been a bit you're in africa of homosapians but we're still talking very small numbers and you're right these small numbers of people the number of homosapians that came out of africa maybe sixty thousand years ago in the main of a g vent you could be talking about you know some people talk about a thousand people coming out and then basically founding the populations zaza: a chris_stringer: of the rest of the world so yes you would think those small numbers where are they even going to meet the new abitoles zaza: exactly chris_stringer: and the fact zaza: yeah chris_stringer: is that a lot of the time they probably didn't meet each other but when you come a place zaza: oh chris_stringer: like europe it's a relatively zaza: yeah chris_stringer: small area you've got challenging climates so at times the climate's really deteriorated and then those populations would be competing with the other economically so in the less good times zaza: m chris_stringer: or when the populations grow in number in the good times they are going to come up against each other and they could be competing economically because of course both populations hume together as they're going to be hunting the same animals they're going to be clicked in the same plant resources they're going to want to live in the best areas where where the game is where the best cave sites are and so on so i think that the zaza: m chris_stringer: tie the genetic data suggest that they were already in trouble in their last twenty thousand years their numbers were relatively zaza: yeah chris_stringer: low some of the population seemed to have zaza: m chris_stringer: been doing a bit of inbred which is not great for the gem pool of course if you're breeding having to breed with your close relatives so some one out tiles were having to do that so i think that their numbers were low their genetic diversity was lower than homosapians today so they already maybe were a species in trouble and then a competing species comes on competing economically with them and that species perhaps had a small edge in competition may be slightly better technology having the use of sewing needles for example would make a big difference in cold environments because you can insulate your babies better you can make better tents than a wind proof that gives you a little leg survival homasappins may have lived in slightly larger groups with more net working that also would be one of your insurance policies in bad times so i think it was you know we know that neadatos were highly capable people highly intelligent they survived very charing and conditions for hundreds of thousands of years but in the end it could have just been quite small margins that led to them disappearing physically and us going ahead so it could have been quite close sing and i think it's probably a combination of features that in the end led to their physical extinction but not zaza: m chris_stringer: genetic extinction because they live on a bit of the movezonein us today zaza: yeah i read a book about cannibalism from a famous zoologist called bill shut recently he's also going to appear on chris_stringer: yeah zaza: this podcast and he referenced another anthropologist that say that may be cannibalism amongst neandertols had a hand in their demise that you know this diseases like cur that developed once you once you practice cannibalism that this might have kind of yeah contributed to their to their eventual demise what do you think about that chris_stringer: yeah yeah so it is interesting that cannibalism happens even in homosapian today it's zaza: yep chris_stringer: not that common but it does happen and we've got evidence of what seems to be canablism at a number of times in the past in different populations in different species so as homo zaza: a chris_stringer: anti cesar from spain eight hundred and fifty thousand years ago it looks like there were individuals there that were butchered and eaten um there's possible home rectors examples with cup marks zaza: m chris_stringer: on the human bones where they may have been eaten and because in some cases this could be crisis canabalism so you know it's a bad winter individuals die and basically they eat them because they don't have much choice about it so that could be some of the explanation but i think there's enough examples in neandatols and indeed in early homasapins that it's not that uncommon and then you come on to explanations of possibly aggression between groups which zaza: h chris_stringer: then involves zaza: m chris_stringer: cannibalism when they if they kill an enemy they then eat but in some cases there's also evidence of cannibalism within groups so as you may in the case of cure where people were eating the remains of their close relatives to try to keep alive their knowledge their wisdom and so on and eating eating their relatives so in the case of nantes i think there's there's examples of both there seems to be examples where it could be what you call aggressive cannibalism and in other cases where it's cannibalism in the groups and as you mentioned this can be detrimental you may actually pick up viral diseases from eating close relatives but i think selection will work on that groups that do this to a access are going to have problems and they will die out zaza: yep chris_stringer: and other groups who don't behave in that exact way will survive so zaza: yeah chris_stringer: i think selection two it's zaza: yeah chris_stringer: unlikely the whole population could have died out because they were eating each other zaza: what about the domestication of dogs was that a factor chris_stringer: i think not in the time period we're talking about so the evidence of domestication dogs is that it came later there's some suggestions that could have happened thirty five thousand years ago but not within the time scale of our sin and toes overlapping as far as we know of course if we had had dogs and the andatole didn't that would have given us a big advantage probably zaza: right chris_stringer: in hunting and so on the evidences it claimed later and in fact there could have been multiple domestications of dogs it probably wasn't even a single event it probably happened semi independently in different parts of the world but as far as we not more than forty thousand years ago zaza: all right we're jumping through vast time lines here because we have a chris_stringer: yeah zaza: limited amount of time i have so many questions but eventually like we said homo sapiens kind of outshines everybody else chris_stringer: it zaza: right i wanted to ask how tough was the world of your average human before the invention of agriculture i've read uvalharari's sapiens book and he says that if you survived infancy life in these small hunter gatherer communities was necessarily as brutal as we might imagine like a lot of problems chris_stringer: ah zaza: such as plagues wars poor nutrition et cetera started arising once we settled down and began farming what do you think about chris_stringer: yeah zaza: that chris_stringer: i think it would have varied so at times life would have been pretty good so in the warm stages even in places like europe there was a lot of food around for people who knew how you acquire it so it's still a dangerous world of course you you're you're out there in a in a place with in europe you have lions hyenas wolves bears um hm these are dangerous places to be and neadtols and our and our early homosapians they were having to confront those animals to require their food was a risk all the time um of death and so there were there were hard times and when the climate gets cold it really is very challenging them and there's an interesting situation in some many out of old sites that people actually mapped in sequences in front when the neandetars were building fires in their sites and the weird thing was when it got really cold there didn't seem to be evidence of hearts in those sites and you think well why not that's the very time they need fire but the problem is even having fire has as a cost because you've got to go out and get that fire wood keep that fire going and in a very harsh winter going out to search for firewood for hours could kill you and so these populations sometimes have to make these these zaza: yeah chris_stringer: hard choices of assessing the risk and zaza: oh chris_stringer: doing something that might kill you or avoiding it and having to do without a fire that night even though it's britally cold so yeah zaza: yah chris_stringer: at times life is zaza: oh chris_stringer: very hard but the times you know if they were able to get enough plant resources to supplement their diet even when they didn't kill a large animal if they had good plant resources they would still have plenty to so we know from modern hunter gather is that you know life isn't always stressful that they do have leisure time once people had the use of fire could regularly make it every evening and they got their fuel they can sit around that fire and actually extend their daylight time and that's probably when population started to tell stories to each other they'd be talking about what happened that day what they're going to do the day starting to tell stories about their ancestors so the presence of fire would have encouraged social bonding social complexity probably tion of language complex language was probably linked with with these gatherings in the evening of people so yeah these tals zaza: oh chris_stringer: and homoseppins would have had those social situations zaza: that doesn't sound that bad no energy bills no rising costs now nine to five chris_stringer: yeah but given a bad winter zaza: okay chris_stringer: times could be pretty zaza: right chris_stringer: hard for you and the end of tiles you know there's this remarkable structure deep in a cave in france at bruni cave so deep in this cave people just care these oval structures made of stalagmite deep in a cave will be on the daylight zone so hundred and seventy five thousand years ago people and we assume they were in the abetolewen de did this cave and built these they got stalagmites they broke them to a systematic size they built dry stone walls and made these oval structure deep in the cave zaza: m chris_stringer: and we haven't got the faintest idea why they were doing that was it just very cold and the clay actually was a milder place to be there was running water there but you've got to have you've got to have artificial light to be down there so they must have had torches and halves there's evidence they were burning animal bones down there to produce light and maybe heat so this is a great mystery that it hasn't been excavated yet they're still mapping it and assessing what to do about it but were they living down there or was there some kind of weird special structure that had special meaning for the new holes but it's on seventy five thousand years old it shows you the complexity of their lives zaza: did they have religion was that maybe like a little temple chris_stringer: that's a very good question we don't we don't know i think homosappians by the time we get home sapin thirty zaza: m chris_stringer: five forty thousand years ago we've got the clave paintings with this great complexity we've got weird sculptures and depictions that are half man and half animal not a real creature zaza: oh chris_stringer: a mythical creature so i think there are the religious bodies then but when we get beyond that i don't know for the end of time zaza: right chris_stringer: and and even for early home saplings in africa zaza: okay chris_stringer: i would say i can't zaza: yes chris_stringer: answer that one you need an archeologist on maybe he zaza: yeah chris_stringer: who's willing to speculate about that zaza: when you find bones of these ancient humans what can we talk about an average age and what did they usually die from chris_stringer: oh zaza: i guess i'm asking if violence was you know chris_stringer: yeah so there zaza: the chris_stringer: are zaza: manual chris_stringer: examples zaza: every day chris_stringer: of zaza: or chris_stringer: yeah zaza: did chris_stringer: i think zaza: people chris_stringer: most zaza: die of natural death as well chris_stringer: yeah i think many of these indivisus have have just died a natural death of course a disease zaza: yeah chris_stringer: that curety quickly leaves no trace on on the bones so so in some of these cases zaza: yeah chris_stringer: yes it could have been an infectious disease pathan some kind that kills them quickly in some cases the there are some very elderly in the adtoles we've got the famous example from shane arc of a neandatol that was crippled probably blinded in one eye with an amputated arm and this individual had lived for years with those disabilities so that's incredible i mean that this individual must have had some social support to survive that long so that shows you there's care within the or groups and that individual in the end succumbed you know but already middle age so yeah i mean we can find old individuals in the tos in my view zaza: yeah chris_stringer: there are more of them when we get to homosapiends so i zaza: m chris_stringer: think that commersaians was able to extend the life of individuals so there is care for individuals and individuals also can support themselves so once you have the ability to weave and we think this was here forty thousand years ago once you can weave you can make nets once you've got nets you can use it to catch more fish you can use it to trap small game and so we can imagine old people who weren't fit enough to join in the hunts any more and run after animals they could still go locally and maybe teach their grandchildren zaza: yeah chris_stringer: how to catch small game and they can even support themselves and so they're not a burden on the group and also the store of knowledge so those old people will remember maybe the last time thirty years ago when the reindeer herds didn't come how do we survive and they might have that knowledge and also they're the store of knowledge of the group they will know the kinship relations they will know how we're related to the people who live over the mountains there that they married zaza: yeah chris_stringer: into our family three generations ago and who were the people zaza: yeah chris_stringer: so those old people actually would be valuable in the end will be once they're not a burden once they can support themselves to an extent with trapping small game and collecting plant resources with their knowledge they can pass that knowledge on it's useful to the group zaza: yeah not sure if i'm right with my dates here but about fifty thousand years ago homo sapiens acquired chris_stringer: yeah zaza: what's called behavioral chris_stringer: yeah zaza: modernity right seemingly out of the blue become equipped with chris_stringer: oh zaza: quote unquote super power such as abstract thought planning trade and co operative labor this seems like something out of a comic book almost like ex chris_stringer: yeah zaza: man or something do we have chris_stringer: well zaza: any theories chris_stringer: yeah zaza: as to how chris_stringer: if you've been zaza: and chris_stringer: reading zaza: why chris_stringer: sapiens zaza: this dramatic chris_stringer: yeah that's the view you get from harris book sapiens that suddenly there's this explosion zaza: right i think he called it the cognitive revolution chris_stringer: yeah and i think that was a view that was around twenty thirty years ago and i was associated with some of it that talk about a human revolution that happened zaza: exactly chris_stringer: we suddenly acquired language and suddenly this gave us all this complexity and that was how we came out of africa and instantly replaced all these other species it doesn't look like that any more i think that if we look at the african record these behaviors have a much greater time depth some of at least so that behavior goes back further and further i think language evolved much more gradually rather than suddenly like a switch coming on than the tals clearly had a lot of this behavior i think some people think that there's basically no behavior l gap anymore between us and the well i don't go that far i think there still are differences and in the den there are signs that complexity in our brain density of nurance for example in the brain is higher probably than than it is in the andetiles but over all neat upset how complex their behavior was they were fully human in their behavior and so this had a long evolutionary history some of it was shared with nadetols when we know more about dinners i think we will see they also had complex lives that individual from harbin that i mentioned so zaza: the dragon man chris_stringer: yeah the dragon man so zaza: m chris_stringer: this fossils at least a hundred and fifty sen years old and living right up in north east china now that area today has some of the coldest winters in china they have an ice festival where they build ice sculptures that stay there for them so the average temperature in some of those months today is minus fifteen degrees the average winter temperature if those people at harbin were living under those conditions zaza: oh chris_stringer: they must have had incredible adaptations to deal with that physically probably their bodies were very large and very wide probably to conserve heat maybe they evolved more body hair again but also culturally it's likely that they must have had good clothing probably had the use of fire so i think to surviving those rats for humans a hundred fifty thousand years ago you've got to give them cultural complexity to survive there so i think this shows us that they were surviving in conditions even colder than we find the antertols so i think there's a lot to learn about even the denisivens and there and the chinese counterparts cultural complexity zaza: okay so there wasn't any sudden jump and then this cave chris_stringer: yeah zaza: painting started to appear and then we chris_stringer: i don't zaza: surmise chris_stringer: think so zaza: that chris_stringer: i mean the paintings that appear of course in europe and and the lovely sculptures and things forty thousand years old they appear they appear to appear suddenly but we now know that there were cave paintings equivalent cave paintings being done in sumatra and borneo zaza: wow chris_stringer: forty thousand years ago so either this complexity developed independently in those regions but i think it's much more likely that it was there in the common and system so in my view and we don't have the it's to back yet i think when we have evidence from africa at sixty thousand zaza: oh chris_stringer: years that we can date properly that we can assess properly we're going to find that people in africa we already do that kind of art sixty thousand years ago i could be completely wrong about that but my hunches it was there at least the seeds of it were there in the homosepians that came out of africa zaza: this is pure speculation for the end but chris_stringer: oh zaza: what does the future evolution of humans look like i'm sure you get a test chris_stringer: yeah zaza: a lot chris_stringer: i do yeah that's a regular question after zaza: oh chris_stringer: talks and it's difficult if not impossible to answer and zaza: right chris_stringer: the problem is that evolution zaza: yeah chris_stringer: doesn't have a forward look of course it's what works zaza: ye chris_stringer: now so it doesn't have forward look about what's going to be needed in the future and when we can say that there are certain things which aren't going to happen so for example sometimes you see these science fiction reps entations of little stick humans with great big brains zaza: oh chris_stringer: that's probably not going to happen because zaza: oh chris_stringer: our brain sizes have actually been getting smaller in the last twenty thousand years on zaza: yeah chris_stringer: average so compared with zaza: ah chris_stringer: our homosapians ancestors as well as neandtols we've got smaller brains and that's partly because we've got smaller bodies and therefore our brains have scaled with those smaller bodies so i don't think we're going to get bigger and bigger brains and i think more sin nificantly is the challenges we face you know if the climate predictions are correct we're going to see conditions zaza: yeah chris_stringer: on the earth in the next two hundred years that humans have never faced and we're going to see e changes in the direction of a hotter world than humans have ever faced so i think the question we have to ask first is how many humans will there be on the planet in a few hundred years and where will they be living and what conditions will they be living under that's what's going to shape their evolution so those are huge unknown i think that makes it impossible at the moment to predict our longer term evolution and even if our species will even be here because the fate of every species that we look at in the fossil records at tally zaza: oh chris_stringer: they go extinct and you know are we going to be an exception well why should we be an exception we'll see zaza: oh it's really chris_stringer: maybe zaza: hard chris_stringer: we won't see zaza: yeah it's hard to internalize chris_stringer: yeah zaza: this coming down from the pedestal chris_stringer: yeah zaza: of you know feeling chris_stringer: oh zaza: very special and unique chris_stringer: yes zaza: of chris_stringer: sure and as i say if zaza: i'm going to need chris_stringer: a zaza: a drink chris_stringer: few little zaza: after this chris_stringer: twists and turns of the evolutionary story and we wouldn't be here maybe in the andoftons or denicevans would be taking over the planet for better or worse zaza: all right this podcast is called our trash so i have to ask you something a little bit trashy at the end is it really still an insult after all we've heard during the interview about neander tolls is it still an insult to call somebody on the under tall chris_stringer: well i would say so yeah i mean zaza: okay ka settled yeah chris_stringer: i mean i would say yeah zaza: yeah chris_stringer: the editors were they were people of there time and our ancestors were people of their time and if you compare our zaza: oh chris_stringer: behavior we were no better or worse than the outer top was like i would say if we go back fifty thousand years life was hard for these people but neandatols had care compassion they were not ape men they were very evolved humans they walked up right as well as we do they had brains as because of their behavior was nearly as complicated as ours no i think it's not an insult zaza: yeah chris_stringer: it shouldn't be an insult to call people zaza: right it shouldn't chris_stringer: that zaza: be an chris_stringer: we should zaza: insult chris_stringer: we should have a positive image zaza: let's change chris_stringer: of the new zaza: that yes chris_stringer: yeah zaza: more justice for the under tall chris_stringer: yes zaza: thank you so much professor stringer this was absolutely fantastic i really hope we get to talk just about neander tells maybe next time if you'll have time and if you want to do this again chris_stringer: yeah zaza: by the way where can people follow your work i think you have a twitter account right chris_stringer: yeah so i'm on twitter at cristriga sixty five so yeah i speak pretty regularly there are news pieces that go on the natural huge museum website on have a lot of resources there on human evolution i have my own very modest you tube channel not much on there at the moment but if you if you google my name and you tube you'll find some talks i've given so and of course there's books you mentioned some of them the most recent ones our human story co author with louis humphrey which is covering the whole of human evolution and britain one million years of the human story covering the british content in british story in the last one million years and that is an amazing story to maybe we can talk about that another time zaza: i would absolutely love to thanks again for taking the time chris_stringer: thank you i've enjoyed it