Science Interviews

Interview

Tue, 14th Apr 2015

Digging up hominids with archaeologists

Professor Lee Berger, University of the Witwatersrand

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A new species of early human ancestor is providing a tourist attraction with a difference. In a first of a kind initiative, scientists in South Africa are about to turn one of the world's most archaeological digimportant fossil sites into a live laboratory, where members of the public can look down into a cave where the two million year old remains of the members of a species of early human ancestor, called Australopithecus sediba, are being excavated by scientists. Professor Lee Berger, who discovered the site and is leading the project, took Chris Smith to the location, which is near Johannesburg...

Lee - We’re at Malapa site where in 2008, my then 9-year-old son made the discovery of the first remains of what would turn out to be a new species Australopithecus sediba. A 2-million-year-old early human ancestor and this site since then has turned into one of the richest early human ancestor sites on the continent of Africa, if not, in the world.

Chris - What actually is the site? What's here?

Lee - What's here is an ancient cave. It was probably about 15 meters under the ground about 2 million years ago. The ground is eroded since then and collapsed leaving us with just the contents. The cave is like a big swimming pool that you'd fill up with concrete throwing bones intermediately into it and in this case, some of those and in fact, quite a lot of them, were skeletons of this early human ancestor species.

Chris - How did the skeletons get in there?

Lee - We don’t know. We hypothesise right now that there were some sort of trap or attractant in here. Maybe if you imagine a pool of water that they desperately needed to get to. Whatever was causing them to go in here, they were taking a great deal of risk to do it and it appears that some of them were dying in the process.

Chris - How many remains of this ancient human ancestors are there here?

Lee - Well, we don’t know the answer to that. That’s why we’re building this laboratory over the top that we’ve begun excavation. But so far, what is exposed on the surface have been two main skeletons and at least the remains of 4 other individuals that we found so far. But every time we open up a little bit of rock here and move a little bit of dirt, we see someone new. We’re introduced to another one of these people that died 2 million years ago.

Chris - Why have you elected to build the laboratory here rather than take these remains to the laboratory?

Lee - The problem we have in Malapa is that as we began working here, we realised this was no ordinary circumstance. We had to have an environment that we could protect those fossils that we exposed as we were working. And so, that required us to build something very, very special here – a laboratory that would protect this remarkable fossil. We also then found out this wasn’t just a normal type of rock that they were contained in. it was a rock that was preserving organic material.

Chris - And what is that?

Lee - Plant remains that are captured in it, seeds, things like that, even food particulates that are captured in the teeth around so we can see what they were eating. Maybe more remarkably, we think we’ve found fossil skin here too. So, there was a lot of reason to protect this site, but we also needed a platform then to take off large pieces of the site to work on them in the laboratory.

Chris - I wonder if – just so that people listening to this can appreciate when you say protect the site – can you describe the vista for people?

Lee - That’s right. We’re seen in the middle of about an 8,000-hectare pristine nature reserve where there's really nothing in here except game. I mean, there are leopards around us, there are zebras, there are wildebeest. All these type of animals here and it’s a pristine environment. We’re seeing at the head of a valley that we can look northward and see out into the Mahale’s bird mountains with nothing but wilderness in front of us at that time. So, we had to build something very special here that I didn’t want to be visible within the environment. On the other hand, this is an important site. It’s a site that people will be journeying to for hundreds and hundreds of years. So, I want it to be spectacular. And I know that sounds like an oxymoron, something that’s invisible and spectacular. That’s why we went to so much design effort and ended up with almost an organic structure itself, almost a beetle-like structure that sits over this site. If you're a tourist, you can actually come and stand over to watch us excavate.

Chris - The easiest way to describe this will be a bit like a wigwam that’s open at the bottom around the covering. So, it’s keeping the weather off. It’s keeping the sun and the rain off. And it means that you can work underneath this walkway because you got a suspended walkway here. It’s a couple of metres - 2 or 3 metres above the ground - isn’t it?

Lee - That’s right.

Chris - Is that so, that you're saying tourists, are you going to bring people out here to look at you working?

Lee - Well, absolutely. Actually, within the next couple of months, you'll be able to come out here as a tourist and probably the only place on the planet you can see a discovery of a hominid live.

Chris - Can you tell us a little bit about the “people” who would’ve been the inhabitants of this environment who you're now finding two-and-a-bit, maybe just under 2 million years later in this pit in the ground?

Lee - If you imagine we were standing here 2 million years ago and they walked out of these trees around us, at a distance, you would say, “Those are humans”. They walk on two legs. Until they got closer, you probably wouldn’t realise what's bothering you but something would bother you. One would be the most striking thing - would be their height. They would probably only be standing about 1.3 metres tall. They also been more lightly built. They would’ve been quite grass or quite skinny. They had longer arms than we do, more curved fingers. So, they're clearly climbing something. They also would’ve moved a little different. Their hips were slightly different than ours and their feet are slightly different. So, their gait would’ve probably been a more rolling type gait, slightly different from the more comfortable long distance stride we had. As they got closer to you, you'd be struck by for the most obvious thing which would be, their heads are tiny. If you imagine, you take a man’s fist and curled it up, that’s about the size of their brain and that would strike you. There’d be almost this pinhead on top of this small body. And that would immediately make you recognise that this is not a human.

Chris - Where do we fit in to this story related to these individuals?

Lee - Well, we don’t know to be frank. It’s maybe just a late member of what we call the australopithecines, the australopithes, which are often considered to be kind of the root branch just before our genus that would give our eyes to us. They do share a lot of remarkable features that only members of our genus have like reduced dentition and the shape of the pelvis, and some other features of the hand.

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