Did Homo Naledi Deliberately Dispose of Their Dead? | Darryl J de Ruiter | TEDxTAMU

today we want to talk to you about a your deliberate dead or more precisely I want to talk about if this behavior is truly exclusive to humans or whether the newly discovered fossil human ancestor Homo Naledi likewise deliberately disposed of their dead deliberate body disposal is it's been referred to as a hallmark of humanity although it varies widely by groupings it is nonetheless a cultural Universal for humans it's a product of our hyper social nature more so than any other animal we know of humans develop powerful social bonds these social bonds were likely crucial for the survival of our lineage we don't have fighting teeth they're fighting claws to defend ourselves the only thing that we can rely on for survival and difficult and dangerous environment is each other and these powerful social bonds drive our funerary practices so we're obviously quite interested in detecting any potential funerary practices in a nonhuman species of animal since no other animal we know of engages no other living animal we know of engages in these complex behavioral practices we have to recognize that archaeologically speaking we do have things like Neanderthals and their ancestors that did occasionally engage in this kind of behavior delivered disposal of the dead but Neanderthals these kind of hominids and hominin is a term that we use to refer to humans and our immediate fossil relatives they had brains about the size of modern humans so we actually even know that Neanderthals interbred with humans so it's a human-like behavior deliberate disposal of the dead in a very close to human relative but apart from humans and Anderton's is there any evidence that any other kind of animal deliberately dispose of their dead I'm fortunate that I work with a large international collaborative research team in the World Heritage Area in how Tang Province in South Africa this area just to the northwest of Johanna is riddled with caves and represents one of the richest hominin fossil repositories on earth and it was in this area that we encountered a cave system called rising star and in this rising star system we discovered a deep dark chamber that we named in Eleni and in this deep dark chamber we found a treasure trove of more than 1800 so far fossils representing at least 15 individual skeletons so far of a new type of human ancestor that we named Homo Naledi now to answer the question that I asked at the beginning our team contends that Homo Naledi did in fact to deliberately dispose of their dead in the dental Eddy chamber of the rising star cave system and if we are correct this would seriously challenge some of the underpinnings of our own human nature what it means to be human what sets us as humans apart from the rest of the animal world Homo Naledi itself represents a curious mixture of very primitive ape-like features alongside very advanced human-like features throughout the entire skeleton without going into too much detail overall body size and shape in Homo Naledi overlaps with living humans small body populations but living humans nonetheless but with the brain size of about 550 cubic centimeters it is less than half the brain size of a living human today now this raises some intriguing questions could something with such a small brain have conceived of their own mortality possibly envision themselves as somehow apart from the natural world could they have had the intellectual wherewithal to seek out and find the Dineh letty chamber and then systematically use it to dispose of their dead accessing the dental Eddy chamber itself is extremely difficult the access route is a long winding path very narrow very difficult to access it's about a hundred feet or sorry 100 100 yards long through tiny little squeezes that ultimately and this is all in complete darkness that ultimately dead ends in the pitch-black dental Eddy chamber now the first part you can actually walk through this first bit it's not easy but you can do it until you reach what the cavers who first got into the system referred to as the super man's crawl which is about a 10 inch high squeeze that requires belly crawling third one as you do you might look like Superman flying the cavers use them often whimsical names for these things eventually after that you finally encounter a large rocky structure called the dragon's back so named for a series of rocky projections that look like what the spines of a dragon's back might look like this is a 40-foot climb to the top before you finally reach the actual access point to the dinna letty chamber which is a 50 foot deep very narrow fissure called the chute now it's a couple of yards from side to side but at its narrowest is no more than eight inches wide so it's extraordinarily difficult to get into as you can see from this image of one of our excavators squeezing her way down into this extraordinarily difficult to access chamber this is the only way in the only way out the only way we have ever found and it's important to note the chute has always been this difficult to get through since the chamber formed so it's always been this hard now as interesting as the hominins that we find there are of equal importance for our question is what we do not find in the dental Eddy chamber every other fossil cave in South Africa we find the remains of countless other animals like antelope and zebras warthogs and baboons hominins our relatives tend to be among the rarest of the rare dinna letty is unique in that we find one type and one type have animal there that's homo Naledi there's nothing else but homo Naledi that demands explanation how do these things get there and again our interpretation is this represents systematic deliberate disposal of the dead in the dental Eddy chamber now before we can accept this hypothesis or support it we do have to rule out a number of other potential explanations for how they got there could they have occupied the chamber and simply died where they lived well we don't find any remains of things like stone tools no remains of meals no cultural debris at all in addition it is in pitch blackness utter darkness so I have to have had some form of artificial light fire but we find no evidence of hearth snow indication of burning and in fact in that enclosed setting oxygen-depleted setting lighting a fire is ill-advised so occupation is very unlikely could they have been moved in through water action periodic flooding washing material in we can tell from the geology of the chamber that water has never flowed through the denill Eddy chamber so it has never been able to get in there the Dragon's Back formation has effectively blocked any water from ever getting into that chamber so there's no evidence for water movement in the chamber the soils that the bones actually come out of are eroded from the walls and the roof of the chamber itself in addition if there were water moving bones in we would also expect to see the bones of other animals and remember we don't find them could they have been dragged in by carnivores like leopards or hyenas the way they are in virtually every other fossil cave in South Africa well we don't find any indication of carnivore activity there's no tooth marks no punctures no crushing no damage on any of the bones in the cave carnivores would also not be able to climb that very difficult 40 foot climb up the Dragons back and then 50 feet down through the chute and into the chamber and then back up and out again because remember we don't find carnivores in there so they would if they got in they would have to get out but there's no evidence for them in addition if carnivores are bringing in car is we would expect to see other animals apart from just Homo Naledi but we don't find them all we find is home on the ladie so there's no reason to implicate carnivores so could it be an accidental death situation because they have climbed into the chamber maybe to escape bad weather dangerous predators looking for some kind of rare resource for some reason they could not get back out oh the geology of the cave indicates that they arrived in multiple depositional episodes that means they didn't get there at the same time they got there many years apart which means Homo Naledi would have had to crawl into this cave and accidentally die over and over again for generations an explanation that becomes increasingly unlikely so that brings us back to deliberate disposal what other evidence supports this notion again it's worth stressing here the only thing we find in this chamber is Homo Naledi combine that with the extreme difficulty getting into the chamber suggest us this is the most unique depositional setting in all of South Africa and our interpretation is that this depositional setting is the equivalent of a cemetery now when we look at the homo Naledi skeletons we see there is an overabundance of very young in very old individuals which is something we all see also see in human cemetery populations the very young and the very old are the most vulnerable members of a group they're the most likely to dock and we are seeing that reflected at dental edium we have almost every bone in the body represented from tiny little ear ossicles to skulls to jaws teeth complete hands complete feet this means they got in there most likely as articulated units not in bits and pieces as they would be if they were washed in or dragged in by carnivores there's also very little morphological variability they all look very similar to each other this is different from what we see in other hominid species where fossil specimens are separated from each other by hundreds of miles and sometimes hundreds of thousands of years and so they tend to not look like to each other homo Naledi looking as it similar as they all do make sense if this is the equivalent of a single homo Naledi group putting the dead members of their group in this chamber over generations they all look like it all look so similar to each other because they're all related to each other now some of our colleagues have challenged our interpretations of deliberate disposal some have suggested there must have been an easier access to the chamber in the past well geologically speaking we don't find another entry into the chamber had there been one we would also expect to see a few things if it were easier to get in somehow in the past we would expect to see sediment washed in from outside and it doesn't exist there we would expect to see bones of other animals because if it's easier to get in other animals would have gotten in but we don't find them so there's no geological evidence that another entrance ever existed others have suggested that really they're just getting rid of rotting smelly corpses which is a sensible move but there are any number of ways of doing that without risking life and limb to get to the dental Eddy chamber you simply walk away leave them but the scavengers have them roll them into a river dump them anywhere else in the rising star system anything but drag them into the dark bowels of this horrible dinna letty chamber some have even gone so far as to suggest homo Naledi were murdered by humans who then hid the evidence of their crime by stuffing their bodies down into the dental Eddy chamber I hear this one a lot every time I hear this one I'm thinking to myself this is telling me more about you than it is about homo Naledi now setting aside the question of why murder and hide homo Naledi for generations in the same place there actually is no indication of Homo sapiens on the scene only Homo Naledi in fact the dental ad chamber predates the earliest appearance of Homo sapiens anywhere in Africa so that argument also doesn't hold the fact remains the most parsimonious explanation is that homo Naledi were using the dental eddie chamber of the rising star cave system to systematically dispose of their dead they did so probably along the following lines a member of their group dies they survivors take that member into the dental Ettie or sorry into the rising star cave system they would have needed some form of artificial light because it's absolute darkness fire presumably though again we don't find any evidence of it but maybe they would have dragged the body through that Superman's crawl which in the past was likely more open and easy to access but then they get to the dragon's back which has always been that difficult to get up they would have to drag the body 40 feet up to the top of this thing and then either carry it 50 feet down into the chamber or we think more likely just push it over the edge into the chute and down into the beyond whatever they perceived it to mean that's probably the more likely explanation they did this over generations despite the fact they all had a brain less than half the size of a living human even though it's in the body about the size of some living humans so we are fortunate that after all this time we are only now just picking up the traces of Homo Naledi now an equally compelling thought to me apart from how fascinating that body disposal is somebody of Homo Naledi those have to be the first one to find the dinner Lettie chamber somebody of Homo Naledi with a brain the size of a large orange explored the rising starch system looking for what we'll never know but the fact remains we have behavior that is otherwise only encountered in large braids things like humans and Neanderthals we have just ratch the surface of the dinna Letty Chamber literally in our excavations and excavation throughout the rising star cave system are ongoing every piece of homo Naledi that we pull out of this cave system highlights the powerful social bonds that are driving this behavior and it's forcing us to recognize that what we once thought was a behavior exclusive to humans might not be so unique to us after all and that this particular absolutely characteristic portion of our human nature might be shared with an animal that was not human thank you very much for your time [Applause]

Channel: TEDx Talks

Views: 38,082

Rating: 4.8534031 out of 5

Keywords: TEDxTalks, English, United States, Science (hard), Anthropology, Science, Speech

Id: qxcrg1jHKWA

Length: 16min 4sec (964 seconds)

Published: Thu May 25 2017