Lee R. Berger

The Leakey legacy and the new "greatest age of exploration" - our ever-expanding understanding of human origins

Richard Leakey's impact on the field of paleoanthropology has been profound, perhaps no more so than in the field of exploration for human origins. In this talk, Lee Berger will discuss Richard's personal impact on his career and discuss recent discoveries and the future of discovery and exploration into human origins in this new 'greatest age of exploration'.

Full Transcript

In the true spirit of why I need bodyguards. I'm going to start by disagreeing with a colleague who spoke a little earlier today. Bernard, I'm going to disagree with something you said. You said Richard didn't have any students and I strongly disagree with that. I'm a student of Richard. A lot of people don't know this, but it was Richard's suggestion and instruction that I go to South Africa to explore for fossils. He was the person who told me that should be my pathway. Of course, in classic Richard style he said, but if you go, I may never be able to speak with you again. He was a mentor of mine, a tough mentor of mine throughout my career and will miss him greatly. But as many have said here, I hope that some of the discoveries that keep happening by his proteges, his students, the people, his colleagues, are going to continue to change the world and excite us about human origins. 

I hope to show you some today. I decided today with the permission of the, I’m here to announce some new discoveries. You'll be the first live audience to actually hear about these discoveries that my colleagues and I are very excited about. They relate to Homo Naledi, that small-brained hominid we discovered back in 2013 with a brain about the third, the size of humans existing from 250,000 years around 250,000 years ago. A mosaic hominid that's both primitive in some ways advanced in others, something that I think most people thought should have existed around 2 million years or so ago. It of course didn't and it surprised I think the world when we realized that there was this small brain hominid existing largely contemporaneous with what we thought at the time was in Africa, populated only by large brained Homo sapiens, at the beginning of a period that we call the middle stone age at a period just before we see the great revolution from about 120 to a hundred thousand years of what we often consider the origins of modernity or terms like that are used. 

What we're going to talk about today is deals with the deliberate body disposal hypothesis that my colleagues and I presented. I think fairly controversially in 2015 to describe why we thought the accumulation of these hominids in these remarkable deep dark chambers in South Africa, way away from where hominids are normally found, where humans venture, why were they there? And we of course suggested at that time that it was because they were deliberately disposing of their dead. Something that I think went down pretty much like a wet balloon and why needed a bodyguard at Lake Turkana when we were telling the world about these remarkable fossils. These images, this is the first time that people will be seeing this is an augmented virtual reality done by National Geographic and what you're going to see is the Dinaledi chamber. You'll be able to venture into the Dinaledi chamber and the discovery, the first discovery I'm going to talk about is what's going to come into the center of the image now, and that is this feature that we discovered back in 2018 after extending our excavations from the old excavation 2013, 2014 excavations to the right expecting a large bone bed. 

We did not find a bone bed. What we found were a number of features that we're interpreting today as graves; Burials of these small brain hominids into the floor of the Dinaledi chamber. They're oval in shape, they have depths of around 25 or 30 centimeters and the bodies appear to be in a fetal like position buried in this remote chambers. This is another look at that. There is some scatter of a few other features that are nearby. You can see the separation of space and sterile ground between these and what we now realize is what we were digging in originally in the Homo Naledi excavation of 2013, 2014 were a number of overlapping burials and that's what had confused us into thinking that it was a series of a bone bed rather than these sort of intentionally dug features. Here you can see more features indicating how the bodies are laid out. They appeared to be in a slightly sitting position and then collapsed into themselves. The material that we saw on the surface when we first got in were from where the burial mounds had actually reduced in size scattering some of the bones that were highest within the features. 

These bodies, we found several of them also in the Hill antechamber. This is another burial of a child in the Hill antechamber. They're actually four children in this burial, one main body of an approximately 13 year old child, two faces and a fetus. It's a horizontal burial into a slope giving quite a convincing sort of situation of the burial as we look at it, and I think something important to look at when you look at an image like that is to see that these are buried at depth. They are not collapsed into the base of the hole. The dirt was supporting them and the dirt was actually coming from material that was actually excavated out. These images were produced by CT scan in synchrotron at the European Synchrotron radiation facility in Grenoble, France and there you can get some of the beautiful images. 

This is still intact and still under study and will be under study to process literally hundreds of thousands of images that the synchrotron is producing, but I would let you look at some of the side images of that, including some of the material. Now, one of the arguments people say, how do you know that these are burials and these are not just bodies that were say laying in a hole on the floor of a cave like that. Well, what happens in those situations in a situation like you see here in a cave is as the body deflates, it deflates like a balloon and you end up with this sort of feature that's not the features we're seen. Our bodies were supported by dirt entirely encasing them. Another idea would be say as that body would be covered, that would be the kind of thing that you would expect to uncover. 

We didn't see this sort of feature when we excavated these. We are seeing bodies that have depth about 25 to 30 centimeters seems to be the average depth of a pit burial or a classic pit burial. The Dinaledi situation is also important because it has an interrupted line, whoops, sorry, backwards. You have an orange layer which fortunately formed about five centimeters down that's interrupted as the pit was dug by Naledi individuals and material of that orange layer is then integrated back into the material that surrounds the body, so it's indicating that the bodies were actually, the holes were dug, the bodies were placed in and then there were recovered with the dirt that was interrupted in the process that it was moving along. Another scenario that people speak of is a fluvial scenario thinking they're moved by water. We can clearly demonstrate from the sediments and have demonstrated in the papers, which were by the way, it did increase by three papers as we were talking. 

They came online and you can actually go look at these papers. There's no gravels, there's no sedimentary structure that indicates any levels of fluvial activity. We've mentioned the word fluvial in previous papers that we published and the reason that we did was we misinterpreted the decay of bodies internally within these pits is a downward movement being driven by geological processes when in fact they were the processes of decay of a buried body within a burial. And again, as a fluvial situation would often end up something like this where you would have the gravel, the small gravels and other unsorted material. Again, there's no evidence of this. The material that's forming that cave at very fine sediments that is falling from the surrounding cave, it's not externally derived and so the disturbances appear to be Naledigenic in origin. At least that's the way we're interpreting it. 

Again, this is the situation that we're finding these Homo naledi bodies in. It appears that all of the bodies that we're finding these situations are in these sort of small pit like burials. I'll also show you some of the other interesting thing. This is again going back to the burial in the Hill antechamber, and I'll draw your attention to the orange rock, the blue bones of the blue purplish bones that are sitting just above that happen to be the hand of that 13-year-old child and it is holding or nearly holding a rock that is remarkably tool shaped. We have called it in the papers a tool shaped rock knowing that our archeologist friends will be arguing about whether this is a tool or not for probably the next several thousands of years. As we do that, and it is a funny story when I show archeologists this because we can make a 3D print of it. They wax about how it looks like a middle stone age tool and that it could be used for woodwork and other things like that until I tell them it's in or near the hand of a Homo naledi child.

Then they say, well, I could be mistaken about that, so it'll be fun to debate. I'm now going to take you back into the Dinaledi chamber for the second discovery that we're going to be discussing. This was made last July 28th when I lost 55 pounds and got into the Dinaledi chamber. I was the 47th person to get in and we're going to be looking at those small pink areas up on the upper right hand side of this image. This discovery is occurring in the hill anti chamber. These are very small spaces. That space is only about two and a half to three and a half meters wide and I'm going to draw you attention to this pillar that to the right is the passage between the Hill antechamber, burial chamber and the Dinaledi burial chamber because on that pillar are rock engravings. 

You have to remember that there is no evidence other than the cavers and explorers my team members that have gone in from the beginning. We actually list the name of everyone that's gone in. There's absolutely no evidence of Homo sapiens or any other species of hominid ever entering these spaces other than our cavers. The chambers, as far as we know, was a known prior to our initial work and there's no evidence of humans moving past the light zones and these situations, engravings you're seeing are about 130 meters back into the cave system. In this extreme environment that we're doing I'll give you a closer look at those. These is one non-geometric shape. They're crosses that does appear to be something applied to the surfaces. We do not know what that is yet. We will be launching of course science for decades around this looking at analyzing what material, but it is a foreign material that has been applied to the dolomite in this area. 

Some of them fluoresce slightly. It appears that maybe flow stone was used to carve them or was put into them to give them a slight fluorescing reflective material. Some of them are triangles squares, there are ladder like structures Xs, lots of geometric forms, very familiar to the very earliest geometric form and very similar to some of the earliest forms we attribute to things like early Homo sapiens. This one from a Blombos cave you can see on the right-hand side in ochre, very similar to some that are carved onto the walls to the left by what we are interpreting as Homo naledi. There are larger images like this very large crosshatching or hashtag object which was discovered on the back of that pillar that you saw in the hallway. This is under polarized filters and you can see what appeared to be areas of it where it has been pounded or pre-prepared and in addition, it is a situation where the previous carvings on this wall were actually covered over. 

They've been covered over by what appears to be sediment from the floor of the cave and then new carving. So what you're kind of visually seeing is only the latest of the carvings that are in this. I'll just give you, there's the natural light image on the left and a polarized image on the right to see that these are not natural forms. You can see first the pounding that you see here. These are dug very deeply into the dolomite. The dolomite is about 2.9 billion years old here and has a hardness scale of about 4.7 on most hardness scale, so between to and diamonds about halfway between the two. These are not minor efforts to do and you can see what appeared to also be pit marks which have been hammered into this. This was an important part of this one that the wavy lines you see horizontally are actually stromatolites fossils that are within the rock and you can see how the carvings actually cross through that and that the carvers had difficulty in actually carving into this very hard rock with multiple striations and just to give you some closer looks at some of the images and see how they are truly carving. 

You can actually see up in the upper right one the order where the horizontal line is carved first and the vertical lines are carved and just some more images up close. There is one panel down at the bottom that image number four, which is a third panel we call panel C within that, which appears to have some sort of treatment of the surface and then multiple carvings all over the surface, but that's for, we're holding the detailed studies of these will come in the future and today literally as we're sitting here, those papers were released. And finally, just some of the more traditional kind of carvings. These four five lines are very common in paleolithic art paleolithic engraving, so they surprisingly don't vary a lot from the kind of early engravings that we're familiar with in there. Just a close look at some of these images by the way, are not easy to do. 

You're working in environments with focal lengths of about 50 or 60 centimeters in these spaces, so it's hard to get these, but we're going to be applying. These are all the non-natural lines, very conservative, look at those to give you an idea of the number of non-natural carvings on this particular panel that had been carved. This is the kind of last image that was left there by what we interpret as a Naledi carver in there. Again, we'd have no idea what these means. I would emphasize that these are done by non-human species, so the interpretation of meaning is going to be very, very difficult and as a comparison with some of the early forms, I think this is fairly remarkable. On your left hand side of the screen is a carving between 30 and 60,000 years old done by a Neanderthal and Gorham Cave, Gibraltar. 

On the right hand side of the screen is what we're interpreting as a Naledi carving inside of the Dinaledi chamber, and I think you can see that there are quite some remarkable similarities between those type of linear carvings, geometric carvings that we produced. The tool shaped rock near the hand of a child does also bear remarkable resemblance to what was interpreted as the oldest art for Homo sapiens from Blombos cave as well with its cross hatches on it. This lithic is about 78,000 years old and was interpreted as either part of a larger object or a lithic itself, but I think you can see that the similarities are striking. Whether that is real or just a human imposition on the shape, we'll wait for people to argue. And in conclusion there's no evidence that Homo sapiens used the rising star system at all are moved beyond the light zone into it. 

There's absolutely no, none of typical lithic scatters or other types of things that you would see in a typical situation of Homo sapiens, and we have no evidence that humans, other than ones that we know of have ever entered the Dinaledi subsystem where this has been discovered. We believe the context of the finds associate the cultural activities with each other. That is that we think that the context of burials within this space and the graves within this space that Homo naledi is the most likely maker of those images or those meaning-making symbols on the rock walls. We would emphasize too that this space has not changed to our knowledge. The geological evidence we have is that it has always been extremely difficult, so difficult that less than 50 humans have ever been into this space, but we are rather large and bulky compared the thinner, smaller brain Homo naledi who probably could have gotten in multiple ways rather than just the way that humans are forced to go into this. 

And we also point out that these burials are not all done at once. They're done over time, so it's ritualized behavior as are the carvings. They appear to be done over a long period of time giving evidence of multiple ritualized use of this, and this is widespread throughout the system now. And we would just finally end with, and this is going to be debated for and why I need a bodyguard, that we believe that our evidence for these burials meets or exceeds what other people have presented for the burials of Homo sapiens in archaic situations. We've demonstrated the disruption of the soils, that it's a refilling of soils, whatever it is. These are holes they're dug in the ground that have bodies in them that were recovered with soil from the same hole, and we don't think Homo sapiens had a pet symmetry or anything like that in there. 

We think Homo naledi is the most likely repeated user of this at 250,000 years prior to and somewhat prior, significantly prior to where we're seeing these sort of levels of behavior in larger brain hominids, which I think deserves further discussion and exciting discussion. And so, to conclude, we're saying that Homo naledi practiced ritualized burial of the dead and created these meaning-making symbols, and this is one of those things. It's a big job from here on, and I know this is going to be viewed for people who follow this field. This is going to be extremely controversial and we're going to get everything from, how do you know Homo sapiens didn't do this? The answer is we don't, but the context is arguably very strong for Homo naledi doing it. 

And so I wanted to do this. I was a little nervous about doing this at Richard's Memorial because Richard was very upset with me when we put Homo naledi into the genus Homo, but we made up after that and it is an incredible moment for us, a team. This is a large team. We're one of the larger science teams in the world, I think numbering around 160 different scientists from all over the planet. We continue to make fascinating discoveries. We continue to make new discoveries. We're not only making them a rising star, but at other sites. And to emphasize what I think has been at the center of every talk here, the importance of continuing exploration, the importance of having endemic infrastructure in the places where discoveries might take place. A legacy of Richard, things that people like I and others have copied because one trick, I was talking with Yohannes I think this morning, I said, “It's no miracle why these discoveries are increasing at these incredible rates”. It’s because we're working 300 plus days a year, we're there. That's a legacy of something like the Turkana Basin Institute. It's a legacy of the investment by organizations like National Geographic and others in supporting us explorers where the discoveries might be made and it's the ethical way forward into the future. I wish Richard had seen this. I think he would've been really angry at me. Thank you very much everyone.

View all Archaeology videos