- Welcome everyone to Wednesday Nite @ the Lab. I'm Tom Zinnen. I work here at the UW-Madison Biotechnology Center. I also work for UW-Extension, Cooperative Extension, and on behalf of those folks and our other co-organizers, the Wisconsin Alumni Association, Wisconsin Public Television and the UW-Madison Science Alliance, thanks again for coming to Wednesday Nite @ the Lab. We do this every Wednesday night, 50 times a year. Back on September 10th of last year, I had the pleasure of going to give a talk at the biotechnology class at the Verona Area High School. It had happened that the news of the discovery of a new hominin, Homo naledi, had broken just that morning. The UW had played key roles in characterizing and describing this new species, so I asked the students at Verona about their take on that story. They're only about 12 miles from this rather remarkable public land grant research university. I wanted to get an idea of what they had gleaned from the media. 

There was one girl in the class, she was a little shy, but she sure seemed to know a lot about that work. And I asked her how she knew so much about it. And she said, "Well, John Hawks is my dad." (audience laughs)  And she was pretty proud about that. It's a great delight to get to welcome back John Hawks. This is at least the third time he's been here. He is the Vilas-Borghesi Distinguished Achievement Professor of Anthropology. And we get to hear tonight about one of his finest achievements. It's a story that has already become a point of pride for the University of Wisconsin-Madison. But Professor Hawks has an even more splendid achievement: he has made his daughter proud of her dad. (audience laughs) Please join me in welcoming John Hawks back to Wednesday Nite @ the Lab. 

(applause)  - Wow! Thank you everybody for coming out tonight. I see some familiar faces out there. I see a lot of faces I haven't seen before. I'm so pleased that all of you have come in to hear about this work that we're doing here at the university and in collaboration with our colleagues in South Africa. It's really exciting stuff. And this is just the first phase of the research. Tom told you about my daughter Sophie. She is the only, to my knowledge, high school girl who's actually helped to pack materials for Homo naledi in the vault in South Africa where they are. So, you know, she had a ringside seat during the workshop when we were describing this stuff. I'll say a couple of words about it and how we came to involve so many people in this description. 

But it has been really special for me to be a part of it from the very beginning. It's been an enormous privilege to be working on this project at the Rising Star Cave because our work with National Geographic, which comes through our project director, Lee Berger, he's a National Geographic explorer in residence, has enabled us to have a lot of media resources on site from the very beginning. And actually my project here at the University of Wisconsin, developing the massive open online course, we delivered that two years ago now this spring to 40,000 people around the world. And that was being organized at the time that this project began. So we actually had a lot of University of Wisconsin video resources on hand. So we have a unique documentation of the project actually from the very point of discovery. And that's a great privilege for me because I have the resources to be able to show you some of these things in people's own words, so that you can see what's going on at the site as we're excavating. And the first thing I'd like to show is a word from one of the cavers who was responsible for the initial discovery of the bones in the cave. He gives you a first-hand account of how they came to discover these bones.  - Caving has always been great. 

Caving, you want to answer the question of what's around the next corner. That's always the question you want to know. It's mostly fueled by curiosity. But as you get into caving more and more, the scientific side of it comes into it. You want to know, how did these places form? What happened here millions of years ago? What happened here billions of years ago? Basically, it creates a fascination with this whole environment. In my wildest dreams I would never have thought that caving would take me to what's happening here. (laughs) You could almost call this a bit of an accident. So, my caving buddy and me, Rick, we were off exploring this cave on a Friday night. We'd gone into a very remote section of the cave, a part that I had never been in before. And in that section, we stumbled upon fossils. (laughs) Yeah, at first, we didn't exactly know what fossils yet. 

We started looking around a bit more until we found a mandible. And that's when we knew this was probably hominid. That was when we got excited about it. (laughs) And since this discovery, it's (laughs) crazy what's happening here.  Pedro Boshoff is a geologist. He's been caving in this country for 50-plus years. And he was asked by Lee to basically go and look for fossils in deep sort of areas of caves. And he'd then spoken to myself and Rick and a few others and said he needs us to come start looking for hominids. (laughs) And on this whole expedition, he has been in charge of the cavers, coordinating who is here and what we have to do and getting everything organized for us.  And since the start of this expedition, from the cavers' side we've been putting in over two kilometers of cabling. Those are for cameras and lights, communications within the cave. And we've also put up safety ropes straight throughout the cave, for the safety of the scientists, making sure there's no injuries. 

And we're here for backup. In case something does go wrong, we are here to assist as soon as possible.  - This is Lee Berger, who's the director of the project. These guys were interested in working with Lee potentially because Lee had been responsible for the discovery of a fossil named Australopithecus sediba. That discovery happened in 2008-2009 and those results have been published over the last six years. They got a lot of attention as creating a new process of discovery where people were exploring new caves. And Lee had gone over the ground across the entire world heritage site, it's called The Cradle of Humankind World Heritage Site, mapping caves that hadn't been previously mapped. So these guys who work underground, it's their hobby to go into caves on the weekends and try to push the boundaries, go into parts of caves where they didn't know that anybody had ever been before. And they said, "Sometimes we see bones when we do this. "Maybe we can work with you "and we might find something too." And of course Lee said, "That's wonderful!" I've talked to him about it many times. 

He did not expect that the first cave that they went into we would make a massive discovery. And yet it was his philosophy that when you're going to start something systematically, you go into your backyard first. Go to the places that you know. And the Rising Star Cave, which is underneath this hillside, which is pretty nondescript, this hillside is basically a chert dolomite hillside, and inside of it are more than a kilometer of underground passageways that make up the Rising Star Cave system. This is a small part of the system map that shows you the area that we're actually working in, from our entrance to the chamber where we found the massive fossil deposit. In this kilometer of underground passageways, are lots of twisty-turny routes. And you get into them really quickly after you go into the cave. How many of you folks have been in a cave? How many of you have been in a cave? Been in a cave, yeah. Okay, brilliant. How many of you have been in a cave where you have to crawl on your hands and knees somewhere? Okay. 

And how many of you have actually had to squeeze so that rock was against your front and back? Yeah. This, if you haven't done it, can be a really terrifying experience. If you're claustrophobic at all, this is a real problem situation. But this is the situation that the Rising Star Cave poses. And it's why our cavers like it. Because you can get into those kinds of really hairy places right after the entrance. So, you don't have to spend all day caving underground to get somewhere really interesting. And it's a great place to bring people to train them on that kind of caving. So, people were really familiar with this cave, and it's been known in the caving community for more than 50 years. It lies less than a mile-and-a-half from at least six very famous fossil sites, including two that have been investigated systematically for more than 70 years for hominin fossils. 

So, it's in a very fossil-rich environ. But fossils had never been noticed in this cave before. The reason why probably is that these really narrow passages and twists and turns make it really hard to access these bones. So, when you saw these guys sort of squeezing through that super narrow place, the way that we reach the Dinaledi chamber, where we are now excavating fossil hominins, is by going down a vertical drop. You can see it there on the edge of the graph. The Dinaledi chamber is on the far right side. And there's this vertical little drop that is about a 12-meter vertical decent that has a minimum width in it of about seven-and-a-half inches, 18 centimeters. So in order to get down that, you have to have the climbing ability to do it. And Steve, who you saw talking there in the video, when he initially found this, the reason why is that he had climbed up this dragons back, which is this ridge of rock-fall that has come down in the distant past. And so you have to climb it, and you get up to the top of it and there this little narrow sort of, I don't know, entryway that you can sort of hang out in. 

And he had wedged himself down in this crack to rest, and he noticed that he didn't touch the bottom. And so he did exactly what your or I would have done in the same situation. (audience laughs) He said, "I wonder what's down there?" (cables swooshing) And he went down 12 meters, and Rick followed him. So, that was how the discovery was made. This was not an obvious place to look. It was very difficult to reach. And that created immediately a problem for our team. How are we gonna excavate in this place? Once they had brought the photos out, and they knocked on Lee's door late at night. And they said, "You're going to want to let us in." And he looked at the photos. He's like, "This is a hominin." And he sent me the photos. He sent it to a number of our senior colleagues who've been involved in the project before. 

He said, "What do you think of these?" It's a fossil hominin. There it is. It's a jaw bone laying on the floor of a chamber that clearly is a fossil hominin. Not a human, but some earlier form, and all the bones that you saw there to go with it. So, it was clear that we had to mobilize immediately. Well, Lee did exactly what you or I would have done in the same situation. He put a call on Facebook. (audience laughs) "Dear colleagues: I need the help of the whole community "and for you to reach out to as many "related professional groups as possible. "We need perhaps three or four individuals "with excellent archaeological, paleontological "and excavation skills for a short term project "that may last the month of November "if things go as planned. "The catch is this: the person must be skinny "and preferably small. 

"They must not be claustrophobic. "They must be fit, they should have some caving experience, "climbing experience would be a bonus." Within a few days Lee had received 57 applications from qualified people all around the world. And on a basis of looking at their records, interviewing them over Skype, he selected six outstanding young women to be the caving team that would be the people responsible for excavating in this very challenging place.  And so, here's our team.  And I'd like to point out second from the left there is Alia Gurtov, who's a University of Wisconsin graduate student, part of our anthropology program. On the far left is Becca Peixotto, who is involved in Outward Bound and a master's student in archeology, now a doctoral student at American University. Elen Feuerriegel is from Australia National University. Marina Elliott, in the right center, is now directing field exploration in the Cradle for the project. She was at Simon Fraser University in Canada. Lindsay Eaves. 

And Hannah Morris, now at the University of Georgia. So our caving underground team, outstanding young women. And over the course of less than three weeks underground, they excavated what would be the largest single fossil excavation ever conducted in Africa for hominin fossils.  So, I'll show you some scenes of the underground work, it's a challenging situation. Everything that you see us working with underground had to be taken through those narrow passages. And that means the power, the lights, the computers, the scanners that we use.  You see them working there in very closed off, sort of contorting sort of circumstances. It became really rapidly clear after very little excavation. This is me in the cave, right. And I put this up here to remind myself to tell you guys how worthless I actually am. 

(audience laughs) I don't fit. I will never set foot in the place where these fossils are. Lee will never set foot in that place. This is a very special chamber that you can only access with the right climbing and caving skills and the right physical makeup. And most people don't have it. It has been a great privilege to be involved in the project in the way that I have. And I like to tell people, especially kids, the cool thing about this is, I'm never gonna be there. And the only way that I know what I do about this place, and I know as much about this place as anyone else in the world right now, the only way that I know anything about it is by doing science on it. And that's pretty cool. We, throughout the project, compared what we were doing underground to astronauts. 

Because it is sort of like, I mean, they're not in space. But it's sort of like a spacewalk. Because when they're working in there, we cannot get to them. It took a half an hour for our team to get from the surface into the chamber to be ready to work, and a half an hour for anything to come back out. So they're really quite remote. And my view from up here on the surface, from the tents above ground is entirely virtual. So here's Lee looking at one of our virtual viewpoints. We have cameras underground. And basically this is our view. We're watching the excavation in progress. 

And we can help to understand what's going on. We can give some expert guidance about what to do. But honestly, it's up to our team to do the best work that they can underground, under some very challenging circumstances. So, I mean, there is something mesmerizing about watching this happen, right? Because you see her working there with a little plastic spoon. Hannah's working in the background with a little brush. This is standard archeological equipment. And what a lot of people are surprised about with the Rising Star assemblage, is that unlike many fossil sites in southern Africa, our fossils are not embedded in a hard rock. Most fossil sites that we work with, the bones are imbedded in a rock that we call breccia, which is made up of bone, gravel, stuff from outside the cave that's fallen in and glued together with calcite, so that it's a hard cement. Our bone is in a soft sediment that's basically like a very fine-grained clay. And to work in it we just have to brush it away. 

The challenge is that our bones are incredible fragile. And I'll say some more words about that later. These bones are not hardened into rock. They are incredibly fragile. And so we come to challenges. Now, when we looked at the photographs from the cave, all of us pored over those photographs before we started excavation. And we said, "You know, I don't see anything here that's repeated. "This looks like it's gonna be one hominin skeleton. "I don't see any parts doubled here." And that would be an amazing discovery, right? Because when you think about the most famous discoveries in my field that have ever been made, things like Lucy, Lucy is a skeleton that's about 40% complete, and that is one of the most important single pieces of evidence of our evolutionary history. We expected that we were gonna find something about that scale. 

And, of course, that was gonna be tremendously important. We would have probably for the first time a skeleton associated from an individual of a South African species that we probably already knew about. Something like Australopithecus robustus, which is found only a half-mile away, at the site of Swartkrans. So, this seemed very likely. It was gonna tell us something that we already knew, but in much better detail and would give us a first ever look at the whole anatomy of something. And that was gonna be really exciting. That feeling lasted until the first day that we sent our team into the cave. Our first day, we got everything arranged. We set up everything do to a run into the cave to make sure that the equipment worked, to bring out one bone. We targeted that jawbone and we said, "Okay, let's make this happen." The jawbone came out and all of us who were on the senior part of the team, who knew the anatomy of all these fossil hominins like our own children, I've got to tell you, looked at the jawbone and we said, "That's not what I thought it was." (audience laughs) The next day our team went to work seriously bringing bone out of the surface of the chamber and brought up three pieces of right thigh bones, all of different right thigh bones. 

It was suddenly clear, immediately, that we were looking at multiple skeletons. This was not the kind of site we thought it was. Suddenly, this was vastly more important than we suspected it was. And so to give you an idea of what that was like-- - Today we're working on extracting a skull. - I'll show you a day at work. - It's looking to be fairly difficult at the moment because the skull is very pliable. It's very, very soft, 'cause it's quite damp down there. It's adding to the problem. So, I think, at the moment, our current strategy is to try and remove the skull in one giant block. As much as we can, anyway, because there's a lot of underlying bones. 

We've got two people working on different sides of the skull. So, I think you've got more eyes on what the actual skull is doing as we're trying to excavate it.  - We are very hopeful that they can get it out in one piece. There's a good chance that they will. But if they cannot, at least we'll have it very carefully exposed and we'll be able to very carefully draw and indicate where exactly each piece came from. And then we'll deal with it in the science end. We can watch their work very carefully, and that's been very helpful for us to understand what they're seeing down there. The coolest thing is that I can't get down there, but it is as close as anyone can get to being there to help them. (machinery rumbling) - [Voiceover] Hi!  - It's early evening, late, late afternoon.  It's time for fossils to come up. 

- Well, they're supposedly bringing it out right now. - If it's lying on its side--(sound obscured by wind). It'd be really nice. - It feels completely surreal. This just doesn't happen. They're coming to begin up. So, if somebody wants to do this, now is the moment. - [Voiceover] It's a big moment again! Every time it's a big moment. - Is that it? All right.  - Look at that. 

 Here it comes. - [Voiceover] There it is. - Let's go get it. (people laughing)  - We got the large section of the cranium out. Glad to be done with that part. There's a lot more down there. There's a whole puzzle of long bones, and other bones, down, underneath where that was. About halfway through the time Marina and I were down there, it was pretty clear that we weren't gonna leave 'til it came out. There was no way we were stopping. The science tent closed a while ago, and they have something to keep 'em busy in the morning. 

So, that's good. (laughs)  - We began digging at that spot because of that skull. We cleared the surface of the chamber. There were bones scattered on the surface as you saw. We were collecting those from the surface. But there was this skull protruding from the dirt. And so we began working on that to extract it. As our team began working around it, they discovered that the skull is actually sitting upon bones. And those bones are laid like pick-up sticks, one on top of the other, as far down as we could sense. And so this became a massive undertaking, just working to get that skull out. 

And once it was out, working on and gradually exposing more and more of this layer of bone that was making up the chamber. Every bone that we were finding, there was a bone of a fossil hominin. And they were in exceptional completeness in many cases. So suddenly this was an undertaking that we were working literally, probably centimeters a day, just clearing outward and making sure that we were very carefully exposing the bones, and then safely bringing them out. Everything that came out of the cave had to be marked, catalogued on the site, photographed, put into secure watertight bags, put into a waterproof padded caving bag and had to come out that narrow passageway. So, it was enormously stressful, let's say, that we had to do all of this to make sure that everything came out safely. But it was also enormously elating every time something would come out of the cave. Because every time we opened up one of these there was the possibility, and most, I mean, more than half the time, it was something that nobody had ever seen before. So, including bones that we almost never find at fossil sites, you know? So, I'll show you some of these bones in a bit. It is really quite a remarkable achievement. 

But as a result, that situation of the fossils posed some very special challenges. For one thing, we worked for 21 days in this site, excavating an area that is smaller than the area of this table. Less than a square meter, and to a depth of less than a fourth of a square meter throughout most of it, less that a fourth of a meter, excuse me. So less than a foot deep, across less than a square yard. This is an amazing assemblage to come out of that space. Most of the bone assemblage in the cave is still there.  We have excavated only a very tiny fraction of it. Also, the unique situation of the cave, the cramped situation, the inability to get straight sight lines and the dense packing of the bone, meant that we needed to study the spatial arrangement of this in a different way than we usually do. Usually, we can set up surveying equipment and very precisely get in the points of things by setting up a station. In our case, we couldn't do that. 

We needed to use a different approach. And the approach that we used was a scanning approach. Here you'll see the results of some of our first scans. We have a scanner that we can take the surface of the excavation at every point. And, in fact, after every bone removal, we take the surface of the excavation so that we have layer by layer, everything that we've done in the site can be reconstructed just back the way that we made it. So, it is really pushing the technology to enable us to reconstruct the arrangement of these things. We're already learning things about the spatial arrangement that we wouldn't have recovered otherwise.  One of the other things that we were doing on the site was we had our underground team. We had a team of more than 20 cavers that were involved in the excavation, running cabling, as you saw, keeping things safe. We had cavers in the cave at all times to make sure we could get things out of the cave, and to get people out if it was necessary. 

All of these folks were camping above ground. And we needed to, A, allow people to recognize the importance of what they were doing. So that if they were taking time away from their families, from their jobs, they could tell people, "Hey, check this out." So, part of the really great thing about our social media presence, tweeting from the site, doing Facebook posts, getting National Geographic video on YouTube from the site, and here our team Skyping out to schools from the site, we were Skyping to schools and countries all over the world, was that it enabled people to really get the sense of something really important that's happening. And it enabled us to share as much as possible the process of this with the public. So while there were aspects of it that we couldn't, we couldn't say because we didn't know. We hadn't studied the bones yet scientifically. We could still tell people what the process was. "Here's what we're doing. Here's what we're finding. "Yeah, we found another thigh bone out of the cave today. 

"We found another mandible. "And here's how we're doing it. "Here's how we'll study these things. "Here's what we don't know about it." That turned out to be a massive resource. We reached out, in one of our videos within 36 hours, it was seen by more than 300,000 people around the world. So, this was really something that people were following everywhere.  The packing up on the site, it was clear that with this assemblage of fossils, at the end of November more than 1,200 fossils. After another week of excavation in March, which we came back to do some targeted work to bring out a couple of things that we knew were at the bottom of this pit, but we hadn't been able to get out safely before, we recovered another 300 bone pieces. So, we had in all more than 1,500 pieces of bone. We needed a very special way to study that. 

That by itself is the largest assemblage of fossil hominins ever discovered in Africa. There's only one site in the world that comes close to this, in terms of fossils. It's in Spain and it's an early form of our own genus, homo. So, what we did was to get the word out, again via Facebook, again via social networks. We need people to come and help us to analyze this material. If we just took the team of senior people who've been involved in the project for many years to come and describe stuff, it would take us years and years and years to do it. We didn't want to do it that way. But we also wanted to take advantage of the opportunity to broaden the involvement of this to a new generation of people. So, we got the word out that we were looking for scientists who were in their early career. People who were finishing their Ph.D., who had already done their research, who already had data sets, or who had recently finished their Ph.D. 

They're in their first position, a post-doc, an assistant professorship, and you've got data sets, "Please apply. "Tell us what you've got." And we have resources to bring people to work on the fossils. And that's exactly what we did. During June of 2014, May and June of 2014, we assembled more than 35 early-career researchers in South Africa, funded by the South African National Research Foundation to do the primary description and analysis of the fossils. This was an amazing time, I think for all of them, certainly for me. Because, imagine, right? You've got people who've been dreaming about doing this sort of thing for at least what has been in their careers to date. And I'll never forget, taking the big, these things are in a vault like a bank vault, right? With a giant door, and taking the big key and opening the vault and doing the (door opening) and letting these folks into the fossil vault for the first time and seeing these fossils. It was really quite amazing. And on site here for more than five weeks, we put more than 10,000 person hours into the analysis of these fossils. We measured them in every way possible. 

We scanned them. We made surface models of them. We described them in relation to every fossil hominin that we had to compare them to. And that included not only originals that exist in South Africa, but high quality copies of things that we assembled by getting everybody around the world who had copies of things to send them to us so that we could compare them. So we really put together a scientific document that shows the anatomy of something that would turn out to be, after our analysis, a species that had been totally unknown to us before. A new species that we named Homo naledi. Naledi in the Sesotho language, which is one of the local languages spoken in this area, means star. And we named it star because of the Rising Star Cave that we found them in. And we named the chamber where we found the bones, the chamber that had not been on the map before our team went into it, we named that chamber the Dinaledi Chamber, which means the chamber of stars. So Homo naledi turned out to be similar in some ways to early members of our own genus, genus homo. 

But also substantially different from them in some really interesting ways. It gave us a picture of a species that we didn't expect.  This is a virtual model made from some of the scans of the bones, some of the 3-D scans. So this is a 3-D manipulatable model. Here's is the bone layout, that shows you the multiple pieces of each part that we have preserved. For the first time, we were able to prepare a description of a new species of hominin based on the entire skeleton.  Usually we find a jaw. And we compare that jaw. We pour over it, comparing it to everything we know about. And we find a few details that make it different, and we say, "Ah, This is something new!" In this case, we're able to compare the entire skeleton. 

And some things really are unique, we've never seen before. And some things overlap with other species. But what was key about this was that the things that overlap with one species, other features would overlap with something else. This was a new combination of things that we'd never seen before. So the skull is the most charismatic part. Everybody loves the skull. We have parts of at least five skulls, and very probably more. When I say at least five, what I mean is that I can show by laying them out that I have the same part repeated five times. So, we have parts of at least five skulls. We have parts of at least 15 individuals' dentitions. 

I'll show you teeth in a bit.  Here's our team working on the teeth, or on the skull, these early-career people. My friend Davorka Radovcic on the right from the Natural History Museum of Croatia. And here's one of the more complete skulls. This is DH-3, Dinaledi Hominin 3. This is the skull of an old woman. And I'll show you that tooth set in comparison to the others. We know how old they are from their teeth, if they preserve them.  Here's a couple more of the skulls.  Here, I like to show how much we have, right? Here are all pieces of the brow ridge. 

 Here are pieces of the temporal bone, just in front of the ear.  Here are pieces of cheekbones.  Here's the back of the skull.  But, in addition to this, we can use our scans to virtually reconstruct things. And this gives us a lot of information about the structure of these things. So, here's DH-3 from the front. And here's a reconstruction of what its endocast was like. The inside of its brain, of its skull, gives us some indication of the outside of its brain. And that doesn't tell us a lot about the function of the brain, but it does give us a great idea of its size. These hominins had brains about a third the size of yours and mine. 

So, they're really quite small.  And yet their skull is structured very much like homo erectus, a species that typically has brains about twice the size of this. So, in structure, it's like a more advanced-looking thing. In size, it's like a more primitive-looking thing.  And just a comparison, here's teeth on the X-axis versus brain size on the Y-axis. Our evolution tends to follow a trend, where if you go from the lower right to the upper left, you're going actually forward in time. So, that Australopithecus, our primitive ancestors, had large teeth and small brains. And as we go up closer and closer to us, through our genus, homo, you get smaller teeth and bigger brains. So there's this sort of dual set of trends. Homo naledi that you see there, the white bar, is small teeth, small brain. 

And that's very atypical. That's not the kind of relation we expect to see.  My friend John Gurche, who's, in my mind, the best art reconstructor of fossils, has done a reconstruction for us of what our most complete skull, DH-1, would have looked like in life. So, that bust is based on this skull.  DH-2 is the skull that you saw them working on there in the cave that came up in, ultimately, a cereal bowl. That was the best thing for it. It laid upside-down in a cereal bowl and we put it inside of that lunch box and it came up through the cave. (audience laughs) And here's DH-1, the most complete of the skulls.  Well, I'll say a few words about teeth because teeth we get a lot of information out of. And we're still getting information out of these teeth. 

We've done micro-CT scanning of all of the teeth in the collection. And so we're now studying the internal structure of the teeth. We will go on to study their development. So, we'll get some idea of how fast these individuals may have developed in their lives by studying that way. We will also study their isotopes to get some idea of what fraction of their diet may have come from different food sources. So, we'll get a lot of information from these teeth. But for me, somebody who's used to working on teeth from other collections that are large, the most exciting thing is, is that we can get a picture of what this group would've been like when it was alive. Because here is an array of the more complete of the dentitions. This is six dentitions representing a range of ages. So that, at the upper left, we have a nearly complete set of teeth, upper and lower. 

These are all baby teeth except for the very bottom ones there, in the upper-left set. Those are the first permanent molars. This is a set of teeth from a toddler around the age of two or three, if this was human terms, in terms of age. Probably they developed a little faster than we do. So, probably a little younger. At the bottom right, you have the oldest individual. That individual has almost worn her teeth completely out, so that they're worn all the way down to the roots. In fossil terms, that usually means that this individual is somewhere in their mid-30s. So, if you think old, old, old, that's old, old, old for these folks. And we have everything in between. 

We have children. We have at least eight children in the collection of a range of ages. We have infants, including one either newborn or near-term fetus. We have, we have young children. We have older children, adolescents. And we have young adults and one very old adult. So, this is a picture of the demography of a population. We've never had that before. Not from one site like this. And certainly not from as primitive a hominin as this is. 

So, this gives us unique information that we're only really starting to be able to work with. This is my favorite thing in the whole collection, because when you have a bunch of loose teeth that you've found in a cave, fitting them together is like the greatest puzzle ever. (audience laughs) Because there are biological clues about which teeth go together and how. And they leave traces on each other so that you can actually discover, "Ah! This tooth goes with this!" Last month, I was there and we had a tooth come out of the cave because we had to sample another tooth for some dating methods, and I said, "Ah! I know exactly where this goes! "I know whose tooth that is." The clues are there. So, this is my favorite, because it's this beautiful, beautiful condition dentition. This is the entire set of lower teeth and we have most of the upper teeth as well of this individual, of what in human terms would be about a nine- or ten-year-old.  But we have not only the skull and the teeth, which we often have at other sites, we have the rest of the skeleton. And we have lots and lots and lots of parts of the rest of the skeleton, including complete articulated parts. So, this in the site is the right hand of an individual. The fingers are bent over like this so that you see the intermediate phalanges, these middle parts of the fingers bent over like that. 

This is what you call a death pose. Because here's the hand and it's gone like this. And all of the bones are there. The only bone lacking from this hand is this little one in the wrist, the pisiform bone. If you fall on the ice, don't do it, but if you do and you throw your wrist down like this, this one you might break or at least dislocate. So, it's there. We don't have that bone. We have every other bone from every other individual, it's amazing.  Put this together and this hand, by itself, and we have parts of many hands. We have 150 hand and wrist elements in the collection. 

We have 190 teeth in the collection. It is an amazing sample. But this hand itself has this mixture of features that indicate different things. Its wrist and its palm is fundamentally a human wrist and palm. But its fingers are very curved relative to our fingers. Its fingertips, you can see them, the fingertips, they're broad at the end. A chimpanzee's fingertips or the fingertips of some of our early ancestors are very narrow at the end. That's because we use our fingertips to grip things strongly when we're making and using stone tools. You guys aren't making or using stone tools but your fingers are still well-made for it. And you grip strongly, powerfully through your fingertips because of it. 

These guys, we've never found a stone tool yet in our site. So, I can't say for sure that they were doing that, but their hands are sure made for it. But those curved fingers mean that their hands were also well-made for gripping onto things like this and suspending weight from them. Which tells us that they were probably climbing. Climbing a great deal, we think. But the one thing that's weird about this hand that we've never seen before anywhere is the bone that connects the thumb to the wrist. That bone in the palm of your hand that moves like this because it's a first metacarpal. And it's the one that roots your thumb there. You can see that this is a powerful thumb. But that bone in particular, the wrist end of that bone is at the bottom here. 

The thumb end of that is at the top. And this bone is totally wrong. Because you can see that it is thicker at the distal end, the thumb end, than it is at the wrist end. This is like a Popeye thumb, right? He's got those massive forearms and they're wrong. This is wrong. We've never seen anything else like this. But I love to show this slide, because sometimes people will say, "Well you found something unique, "that was probably just a weirdo. "That was probably just a strange individual." We've got seven of these! (audience laughs) They're all morphologically the same. They all have this strange character. And that tells us that this is actually a characteristic of Homo naledi. 

This is something about the way that it was adapting to its environment that gave it this unique morphology. You can see the curvature there of those fingers.  And the forearms, the upper limbs let's say, are actually really slender. You look at that humorous. I've printed it here. This is a really slender bone. And when we look at the rest of the post, and we have juveniles of most of these as well. So, we can look at that developmental aspect as well. This is an adult humorous. This is a juvenile humorous. 

And on both cases the head of this, that connects to your shoulder is broken off. But the distal end is there here, and just short of there here. So, this is the bone of probably a six- or seven-year-old and this is the bone of an adult. These are little, slender, but long compared to how thin they are. And we're gonna see that throughout. The shoulders of Homo naledi, to make a long story short, are like this. They are oriented on the body of Homo naledi as if they're made to reach up and climb stuff. They are not oriented in the way that ours are, which is fundamentally with our scapulas down here and to the side of our bodies, well made for winding up and throwing stuff  or hitting stuff.  Homo naledis are made for climbing stuff. And the clavicles match, these long, long collarbones. 

 We've got lots of feet. My graduate student, my Ph.D. student I should say, who now is an anatomy professor at Lincoln-Memorial University, Zach Throckmorton, came from UW and is one of the experts working on the feet of Homo naledi. We've got many partial feet, many of them also found in articulation in the site. The most complete one shows a foot which, in Zach's words, right, "This is as human as yours and mine." It's got the arches that our feet have. It's got the proportions of the toes that ours do. The lateral toes there, we have most of the bones of those. But it's really hard with little toe bones to know for sure which is which. So we don't show them in the diagram like this. We've got them oriented there on the cover of the "On Wisconsin." So you can see all the toe bones, and one finger bone. It's not my fault. 

(audience laughs) You see all the toe bones. This is a toe that's made for upright walking, bipedal striding, but in a essentially human-like way. It is a human foot. And that contrasts with things like the shoulder, which is not like a human shoulder.  The lower limb, here's the tibia. Likewise, long and slender, and you start getting a picture for how big those guys are. You can see that all these bones are slender. All these bones are skinny. Whatever height they are, they seem like they're not very thick. They're not massive for their height. 

When we work with these numbers from the long bones, we estimate that these guys stand about four-and-a-half  to five feet tall. So they're human-sized. They're not big-human-sized but they're the size of small-bodied human populations. People like Pygmies, like the Khoisan people of South Africa, yeah, South Africa, like the Andaman Islanders. Folks around the world who are small-bodied populations, Homo naledi is their size. Again, juvenile tibiae.  We've got at least eight adult proximal femora. I've got a bunch of them printed here as well. The femur is different from the rest of the hindlimb. The feet are human. 

The tibiae are long and slender, but basically human. The femur, across it, is mostly human. But you get to that proximal femur, and the neck of that proximal femur, the part that connects to your hip joint, is long. And I'll tell you exactly why that is...  when we look at the hip...  which is flared outwards like this. And so if I take a piece of the hip, and the hip is a tragedy. My post-doc here, Caroline Van Sickle, her specialty is the hip. And she worked with us on the team that was working on the hips. Some of you might have gone to her lecture when she did Wednesday Nite @ the Lab. 

So, I always tell people that the hip is a tragedy. And she's like, "Why is it tragic?" Well, it's tragic because we have, actually, a lot of broken pieces of it. And we get a lot of anatomical clues from those. And I've just sent her to Madrid where she's working with specialists who've reconstructed what this hip might've looked like from the pieces. But the first clue that we get is that when we orient this properly, you see that is just flares outwards like this and the femur necks are long to match. This is a dynamic that we see in some of the earliest bipedal hominins, the australopiths. It's a dynamic that shows that they have great force to keep their bodies upright. They have very good leverage for that. And they have a lot of hip swing. But it's not very human-like. 

We have a much more vertically-oriented hip. And ours are much better made for long-distance walking and running. So, this is a very primitive confirmation to go with that very human-like foot. And that's a bit of a puzzle for us. We haven't worked it out yet.  So, when you look across the whole body, Homo naledi, and this is John's drawing of this, and I think he's done just a great job. On the very left, we have Lucy. Her species is Australopithecus afarensis. It's one of the most primitive bipedal hominins. Afarensis is small. 

Lucy stood just a bit over three feet tall. Next to her is the most complete skeleton of Homo erectus, reconstructed. This is a skeleton from Kenya. It's called the stripling youth, or the boy from Nariokotome. And people always remember how to say Nariokotome because it's pronounced like frontal lobotomy. (audience laughs) I will never forget when I was taught that. So, now I'm transmitting it. And on the right you see Homo naledi. Homo naledi's in between these two in stature, the size of a small-bodied human. But I think John has done the shoulders especially well. 

He's done the thinness well. He's done the stance, I think, well. It is a very human-like stance. But it doesn't look quite like us. And that's what you get with Homo naledi. We do not know how old the fossil assemblage is.  We have excavated it from a very uncommon setting. It does not have the bone embedded in rock. We do not have as clear of indicators of the antiquity of the bone. And you might say, "Well, the bone's probably young." And that's a possibility. 

This bone could actually be relatively young in fossil terms. That would still be tens of thousands, hundreds of thousands of years old, but it might be very different in age from other things in the area. But I have worked on hominin collections, Dmanisi in the Republic of Georgia for instance, where the bone is two million years old nearly, but is also very fragile and not embedded in hard rock. So we don't know for sure the age of this from the condition. We are working in the site to discover the age of the fossils by bracketing them with flow stone deposits. We have flowstones that are above our fossil deposit. We're working to discover what is at the bottom of the fossil deposit. And the density of bone means that we don't just dig right through with a drill, right? So we actually have to be very careful about this. And that is holding us up on determining a date. But you can see the possibilities. 

It is a very primitive member of our genus. It's like maybe the earliest examples of Homo erectus with a smaller brain. It's like Homo habilis, a very primitive member of our genus, with a smaller brain but with more advanced aspects of the feet and hands, for instance. So, it looks like it's rooted in our family tree around the time that our genus originated, maybe two to two-and-a-half million years ago, possibly earlier. But the fossils may be much younger than that. They could be that age, right? It could be, "Wow! This is our ancestor." Or it could be that the fossils have survived alongside other species that evolved more similar to us. And we don't know. So, when we draw the family tree, you can say that homo here is the bottom branch, and these orange species are different kinds of homo. Homo naledi is this green one. And maybe it's very recent. 

Maybe it lived alongside of even modern humans. That's a possibility. Maybe it's the age we think it is. It's even a possibility it's much older than it sort of ought to be. In which case it would establish an earlier date for the origin of our genus than we thought. So, discovering the date takes on some primary importance in understanding what happened to lead to the evolution of humans and other species of homo.  Well as Tom indicated, we had a lot of news with this discovery. This is my photo on the New York Times, just wonderful. The international attention to this has been just enormous. It has been really, really great to see that our science has gotten this kind of attention. 

This is the skull right? I'm the one who made away with the one the vice president kissed. This is the vice president of South Africa who appeared at our announcement and was really nice about this. I just, it is so neat to be in South Africa, in many ways still a developing country, still investing in its strategic areas of scientific advantage. Fossils, obviously, a huge area where they are pushing their science and to have, at the highest levels of government that recognize the importance of this.  At our announcement, the vice president said, "This work demonstrates the scientific basis "for a common humanity." And that is what it does. This is showing our ancestry. The things that tie us together, historically, are things that came from these ancient species. And discovering how they lived is telling us about that shared history that every human around the world has, especially in countries like South Africa where you have this huge human diversity that has had a history of great troubles. Being able to contribute on the scientific side to showing the common humanity is incredibly important.  Of course, any time there's a great discovery, you get in the comics. (audience laughs) "Fossils of New Human Species "Found in African Cave" is the headline. 

"Did we discover an extinct caveman too? "Not quite." He's got the artifacts of our political campaigns, Trump has a club, Donald was here.  But in South Africa, this took on a really, sort of more spirited view. This was when the Rugby World Cup was happening. And as you can see here Homo naledi was ready to join the team, the Springboks. If you guys have seen that movie with the Springboks. It really is like that there. They're crazy for their rugby. And, it's neat to be, "This is the most experienced Bok Team ever, "with a million years between them." (audience laughs) But when it comes down to it, we have just an enormous amount of work left to do. We've done as much, I think, as possible to get this out to the public. Not only through our participation in social media, but also here we put the fossils on exhibit. For the first time ever, a new fossil discovery of hominins on exhibit for the public. 

And record-breaking 10 times the ordinary visitation to the visitor center of the World Heritage Site to see these fossils. As you can see, school groups, people of all ages coming out. It was just a unique thing. When they left they put on a farewell concert and they had some of the greatest acts in South Africa on stage to salute Homo naledi. It was really something. So, that was really special. But we've also made great strides in sharing the scientific results more broadly. In paleoanthropology it is... From my point of view, I've been in the field for 20 years, from my point of view, sad that our students cannot handle fossil casts from some of the most famous fossils in the world. You can't get a cast of Lucy now. 

You cannot get copies of these fossils to show to your students. We want to change that. We made our priority to share this information as broadly as possible. We published our work in eLife, an open access journal. And we put our fossil scans on the web so that anyone can download them. We, to date, have had nearly 10,000 downloads of these from around the world. And people are using those to print out fossils everywhere. I show up places to give a talk and they'll say, "Here's our naledi!" It's amazing! (audience laughs) I've been printing them in my lab like crazy, right? So, I've got fossils to bring in. But for us the important thing is that this is a South African discovery. And so the chancellor of Wits University, the university that hosts our work and hosts the fossils, at our announcement said these words. 

And I think they're really important. Because they show the way the world of science is changing. "We often talk about science as having no boundaries, "but in our world scientific knowledge "has become commodified, and too often, "what should be the bequest of the world, "the bequest of a common humanity, "is locked up under pay walls that postgraduate students "and researchers cannot get access to." We're at a tremendous advantage here at the University of Wisconsin because almost anything that I want to read, the library will get for me. This is not the case in most of the world. It is not the case in South Africa. And so to be able to do this work in South Africa and give it to the world. As he said, "What we did when we made this discovery, "was we put the cameras in the cave, "we streamed it live. "We partnered with eLife, an open access journal, "to make sure that the discovery "was available to all of humanity. "And what we did in that practice, "is create the first elements of a common global academy. "We're not simply going to be beneficiaries "of open access, but we are going to be "contributors to open access." This isn't Africa coming with its hands out looking for people to give stuff. 

This is Africa providing the best that it has to the rest of the world as a bequest of a common humanity. And so, to be a part of that project, with that priority, for me, is tremendously important.  You guys are gonna want to know, how did the bodies get in there?  We have a very unique situation. A situation in which we have no other medium or large mammals other than hominins. Aside from the hominin bones, we have six pieces of a bird's leg and some teeth and a couple of other bones from mice. And those mice teeth and bones, we think, we're pretty confident, were there before our hominins. They're in a different deposit than our hominins. Our hominins are there in what look like at least two different depositional events. The bird we think probably came in later, 'cause it's on the surface, it's preserved differently from the hominin bone. That's what we got. 

This chamber is where it is. It is remote. It's, for our team, very difficult to reach. We do not believe it would've been as difficult to reach in the past. Caves change over time. And we think the geology of this cave probably made it easier to access in the past. But we can tell from the sediments in this chamber that this chamber was never open to the surface. These hominins didn't fall in. They were not washed in. There's no, there's nothing in there that's indicative of water of the strength that it would take to move bone. 

And we've got parts of bodies that are fully articulated. It's clear that the bodies entered this chamber whole. We've got great traces of what happened to these bones at the time of decomposition. We've got the little traces that beetle mandibles make on it. But in all of this, on no bone do we have something that is a mark made by a carnivore.  So, there we have it. They weren't dragged in by carnivores. They were not subject to predation. There's no carnivore that only eats hominins anyway, not 15 of them. (audience laughs) They're of all ages. 

This isn't people that were exploring a cave and got unluckily trapped there, right? Unless they were exploring with babes in arms. They were not living there. There's no sign of detritus that they would've, you know, of the stuff that they ate, they left in there. They were clearly not using this chamber. They may have been using other chambers. We're investigating this, but they weren't using this chamber to be in, except to have their bodies in it. We think the most likely scenario is that Homo naledi deliberately deposited them there.  This species with a brain a third the size of ours was collecting its dead and putting them in this place.  That tells us something really interesting, really important I think.  A lot of people come away with that and say, "Well, did they have religion? "Was there some belief system that they had?" We don't think that. 

I think it's not a scientific question, at this stage, obviously. We don't think that. We think that what they had was emotion. We think that they had feeling for other social beings. We see this among other primates. So we know that this is something that's not a stretch. What's different is that Homo naledi had a culture that said, "When the bodies are dead, put them here." That's a minimum. That's all that it took, we think. But that does tell us a lot. It tells us that these were cultural creatures. 

We can't find a better explanation at this moment for what happened. But we're still investigating.  I can tell you that there are other hominin remains inside the Rising Star Cave in different places. So, we will learn more about what happened here. We may discover other species of things, or species we already know about. We may find more of Homo naledi. Just this week, from a nearby cave, Sterkfontein, was reported a new area. This cave is one of the most famous in the world for producing hominin fossils, but a team was working in a different area of the cave and recovered a tooth and a finger. And that tooth could be Homo naledi. It looks a lot like it. 

We're not sure. We have to look at it in person. But one of the people working on it is Travis Pickering, here in the department of anthropology. So, we've really got the corner on the market of Homo naledi at the moment. It's exciting because anywhere we look, we could turn this up and discover the next piece of evidence. But what this cave tells us more than anything else...  it's less than two miles from some of the most famous fossil sites in the world, and there it was, with the largest assemblage of fossil hominins ever in Africa waiting to be found.  The next place we look could have something just as cool.  It's clear that we've only begun to scratch the surface of what there is to discover. In a place where people thought, "Well, people have been looking for 70 years, "what more could there be to find?" When you find something like this, and realize that the rest of the continent is there, unexplored at that level of detail. 

Our science is going to change a lot in the next several years, and this is just the beginning. So keep watching. This is gonna be an exciting time. We're discovering new things all the time. We're going to have more new things out of Rising Star and within, I'd say, a year, you're going to hear some really crazy stuff. So, keep watching. Thank you everybody for coming out. (applause)