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The Secrets of the Dead
With Martin Pickford and Brigitte Senut
Paleontologists
Friday, May 10, 2002; Noon EDT

In October of 2000, while examining a geological formation of volcanic rock dating back around six million years, paleontologists Martin Pickford and Brigitte Senut discovered bones from what appears to be an upright-walking, hominid skeleton. As the first major discovery of the 21st century, the find was initially dubbed "Millennium Man" before being given the name "Orrorin," which means "original man" in the local Tugen dialect. Remarkably, the bones are the oldest hominid remains ever discovered -- so old that they come from the time when the divergence of man and ape is thought to have occurred. In fact, they could be the blueprint for the first generation of the species that ultimately evolved into modern humans. "Search for the First Human," a Secrets of the Dead special premieres on PBS Wednesday, May 8, 2002, 9:00 p.m. EDT (check local listings).

Pickford and Senut were online Friday, May 10 at Noon EDT to discuss their discoveries and the search for evidence of the first humans.

A transcript follows.

Editor's Note: Washingtonpost.com moderators retain editorial control over Live Online discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions.

Nashville, Tenn.: This is all so fascinating. What lead you to the Tugen Hills of Kenya? Do you study sites based on the geographical strata performed on the dirt?

Martin Pickford and Brigitte Senut: Martin: Yes, I was really lucky to do my PHD thesis in the area in the 1970s, so I already knew that it was good area and back in 1974 I found the first hominid tooth there. And then, when I was invited back in 1997 we launched a proper expedition. So, the area has been known for a long time for being a good place to look for fossils.

Washington, D.C.: Would you describe the climate of Orrorin tugenensis'environment?

Martin Pickford and Brigitte Senut: Brigitte: The environment was quite an open forest, lake, hot springs were evidenced and stone. And also, we have petrified vegitation and also leaves and wood. So, good evidence of hot springs, so there would've been begonias. A lot of foresst and trees, because we've found evidence of monkeys. It was a kind of bush environment. Big trees for him to cool down. So probably quite warm.

Kettering, Ohio: If Lucy has "moved" to a side branch of our family tree, which known fossils do you now place between Orrorin and h. sapien?

Martin Pickford and Brigitte Senut: Many. That's the answwer (Brigitte).

Martin: First, we think australopithicus didn't give rise to homo. There's a big gap between Orrorin and homo, but right in the middle of that gap, there is an animal known as prae africanus. And it is known and seems to have been more like modern humans. So, we think that humans arose from this and this arose from Orrorin.

Alexandria, Va.: You've said the bones of Orrorin had elements of human bones, while also being strangely ape-like. How can you tell this? What do you look for?

Martin Pickford and Brigitte Senut: Brigitte: We got several apelike features which are retained on the arms from early stages of evolution. This was still in Lucy and Orrorin. But the new thing for Orrorin, still exhibits bipedal features -- which are oriented closer to humans, but not completely human. They are not homo, but Orrorin.

The head and neck of the femur and deposits of bone, all these patterns are more like humans and definitely different from lucy. And lucy in these lines is less human.

In terms of size, Orrorin is also much bigger than Lucy and his teeth smaller than hers. This is one of the clues that led us to believe our discoveries. ANd humans are small skeleton, small teeth as well.

Martin Pickford and Brigitte Senut: Martin: Think back at 6 million years, you're getting close to the split between apes and hominids, so itS normal to find a mix of characteristics. The forearm looks apelike, but so does lucy's arm.

The hindleg is very much more modern human looking. So you get this duality of locomotive repetoire. Orrorin was still climbing, but walking bipedally on the ground.

Columbus, Ohio: The Orrorin fossils were found on or near the surface of a dried stream bed. How do we know that the creature's remains were not incorporated into that soil and its other six million-year-old fossils more recently, maybe even after the overlying volcanic basalt had eroded away?

Martin Pickford and Brigitte Senut: Martin: That's quite true, we found most of the stuff in the recent soil, but we excavated in situ and found three or four pieces in the old strata. The stuff that had been washed out by erosion were the same composition.

I had nightmares about this, because there have been claims like this that didn't turn out.

Orrorin really is associated with the 6 million year old sedement in four different localities.

Phoenix, Ariz.: If man evolved as we have been led to believe, how is it that the supposed ancestor of man -- a primate such as a monkey -- has not continued to evolve?

Martin Pickford and Brigitte Senut: Brigitte: They did evolve. As elephants, giraffes, chimpanzees. All animals have evolved. Even with monkeys we find are not the same as the ones today. And giraffes -- their marks -- all of these animals have evolved since then.

New York, N.Y.: What do you think lead to the extinction of the australopithicines? If Lucy was not our ancestor what was she?

Martin Pickford and Brigitte Senut: Brigitte: She was a great aunt!

Several things to consider. Body size and environment. The environment became dryer and a major climactic change when homo took over. So it may be one of the things which just make them have difficulties to get food to survive.

We don't have a very clear explanation. Small body size and the lack of available food.

Martin: We can say, there were several other animals that went extinct -- some elephants and antelope species. SO there was a great dying off at this time about 1.8 million years ago. The last austalopithicines had huge molars and specialized on eating some kind of food that became very rare or hard to compete for. But this is just hypothesis. They may have become the favorite prey of some kind of carnivore.

WHat we do know is that they were very different from homo. And very unlikely to give rise to homo.

Herndon, Va.: Is it possible to obtain DNA from the bones you discovered?

Martin Pickford and Brigitte Senut: Brigitte; Unfortunately not. THey're too old. THey are heavily mineralized. But we got a lot of information anyway.

Orono, Maine: With this discovery, will we finally be able to put the nail into the coffin of Creationist thought?

Martin Pickford and Brigitte Senut: Martin: No, we're confusing two different spheres of the human mind. Religion and science -- they're very different aspects of human thought. I personally don't have an axe to grind in this. If I lost a loved one, I wouldn't think about it scientifically and I'd go to a church for some sort of solace, whereas if I broke my leg, I would go to a doctore who has scientific training.

So paleontology is on the scientific side of things. So, being a scientist, I look at it from the scientific angle, but I can understand why some people look at it religiously.

So, I think there will always be some people who will approach this from a religious point of view.

Tilburg, the Netherlands: Where the bones found scattered or near eachother?

Martin Pickford and Brigitte Senut: Brigitte: Scattered in a gully, but some were found close together. Parts of the mandable and teeth. And all the other scatters. ANd dont' forget there are four different sites.

Columbus, Ohio: The program indicated that enamel is still present on the fossil teeth of Orrorin. Is it possible that dental pulp my still be preserved within the tooth, sealed like a mini time capsule? And can the pulp be tested for DNA residue?

--Gregory O'Brien

Martin Pickford and Brigitte Senut: Martin: The dentine is there underneath the enamal, but so heavily mineralized, so I'd be very surprised.

Baltimore, Md.: What was your reaction to the discovery once you realized what you had found?

Martin Pickford and Brigitte Senut: Brigitte: Two reactions. It was very freeing really. Because we knew it was something really important. On the other hand, my reaction, I thought this would be a big hassle because we'd have to get people to accept this discovery. And, one of my reactions was to tell Martin let's just put it back in the lake!

It was a shared thing because I find complete skeletons of a small rat just as exciting as a hominid. Knowing how big this was puts a lot of pressure on me. But we knew it was very important. But we are paid to find fossils, so you also need to be dispassionate about this. Finding a rat is just as important. It's because hominids are so closely related to us that people get so passionate.

Martin: I was very excited, especially finding the femur. When I realized this was bipedal I knew it was going to cause a paradigm shift. Two years ago, people were talking about the chimp human split at 4.5 and here we were at 6. And we could tell it straight away in the field, then went back to the lab and proved it. So this was foremost in my mind. It wasn't just bits of legs and arms, but we had a reasonable picture of what Orrorin was like.

But also this anxiety about was it in situ and wondering what tests we could do to prove beyond a doubt that this was correct. I slept soundly once we proved this.

The hominid origins, the people involved in it, they tend to get very excited about these things for the reasons Brigitte said. A lot of politics involved. ALl of that was worrying. And if we made a false claim people would ruin us. But we knew it was a good discovery. We can have fun debating the details now.

It puts a lot of scientific questions into doubt. People we've shown the fossils agree that the claims of bipedal are correct. A cross-section of scientific cultures.

Ann Arbor, Mich.: How do you decide where to search for hominid remains and how widely do you continue to search, once hominid remains have been found at a particular site?

Martin Pickford and Brigitte Senut: Brigitte: Female intuition!

We do a background on the field and Martin had the Ph.D. from the late 70s, so we already had a framework and we'd worked in a lot of places in Africa already. And when we were invited by Kenya we were already in Africa and it was a good convergence for us in terms of environment and climate change and so on. And we didn't expect to find this, and we'd done two or three trips before this one.

We didn't think of finding something this important. The interesting thing -- the main site was found by our chief worker, but its a patch that Martin noticed years ago, but never went through.

You get the geographical background which gives you the age to look for. And for many years I doubted Lucy was our ancestor so I knew we had to look somewhere else. You have to go into deeper, older strata to truly understand evolution.

And then, you have to walk, sweat, sometimes for days without finding something. Fossils are a very rare thing. SOmetimes they concentrate because of water currents -- so its not a given find. So in a sense we are lucky and it was a good reward from the heavens.

Martin: I'd like to say that we've located over 200 fossil sites in these hills and ranging in age and it takes time to visit all these sites. You can do one or two a day. We were specifically concentrating on three time periods -- 15 million years, 6 million and 4.5 million and found a couple hominids there. The creme on the bun as it were was the discovery of Orrorin's skeleton. We have a very good team of young Tugen and Kip who runs the crew has a flair for finding fossils. With this new team we're getting more and more. So now we're going back to sites we'd already been to and finding more. So we expect to find even more.

The great thing about where we found Orrorin -- it is a huge site and will take more than a lifetime to explore. So the potential for future finds seems quite good.

Arlington, Va.: How well do you think the Kenya government is handling the competition between your type of research and the economic pressures of tourism?

Martin Pickford and Brigitte Senut: Brigitte: When we linked with Kenya's NGO, the aim was to bring culture to the people and our case was to deal with heritage of the area. And now we've just opened our new museum in the Tugen hills, so this is a joint effort. We've the blessing of the Kenyan and French governments. So the ministry of tourism is quite interested and trying to market the place. So people are very happy because for the first time they could see the results done on the field on a very grassroots level and when we opened the museum it was so crowded we had to limit the entrance. People came from all over for the opening. So in this situation, what interests me as a scientist, paleontology does bring a lot to the country because it brings knowledge to the people.

IT was very important that the local people get their heritage known for themselves. In the past people had to go to Nairobi to the museum. So it has come back to the people and will be curated by people from the area. You can't work in these countries now like you did in the early years, no one benefits from going in, finding the fossils and leaving. No one benefits from that locally. So I was very proud of this.

Martin: Very interesting question. Because science and tourism are not incompatible. There are lots of tourist who whould like to see fossils well-presented. But what's happened in the past is that fossils would be collected, taken to Nairobi and locked away. So with this new concept, once the govt decided to liberalize the country they didn't stop at liberalizing politics -- they also did the economy, agriculture, health -- and one of the last monopolies to be liberalized was the museum system. And the government decided the local people needed to see their heritage. So they now encourage people like me and Brigitte to come and study and to let the heritage remain with the people. At the moment it's a bit out on the limb, but if they build a circuit to see this, the wildlife and the area will attract many more tourists than they do at the moment. And the government loves it. They thought we were giving them honeyed croissants. So there's nothing incompatible about these things. SO, the science will actually help.

Brigitte: It is important, but has to be done on a controlled basis. We don't want the site destroyed, so getting the local people involved in the curation is wonderful for the national heritage.

Nelson, British Columbia, Canada: It seems to me that one of a number of evolutionary advantages of bipedalism is that generally (though by no means always), a taller animal stands a better chance of intimidating a shorter one. Would you concur that upright walking may well have allowed our ancient ancestors to compete just a little bit better at scavenging because standing up would have made them slightly more menacing? (There is of course the other obvious advantage that the taller you are, the better the view).

Martin Pickford and Brigitte Senut: Brigitte: It seems it all came out in that question. People dont' think in terms of why things are bipeds. We known for years that you had a lot of primates climbing trees and when the trees get scattered either you to the ground or leap from one tree to another. If you leap, you don't want to be too big or make sure the tree is big. In hominids, it was also a size evolution. Early hominids were not small.

WHen you go to the ground, you have two other options -- biped or quadroped. WHen you look at all the works done in America and Japan and Europe it shows that some muscles activated for vertical climbing were also activated for walking. It would cost less physically to walk on two legs rather than four.

This is was just a more naturalistic evolution. An environment was changing. In today's culture, man is still the only creature that can walk upright for a long period of time. We also still can't do it all day. We have to sit and to rest.

So this doesn't make us higher or smarter. It is used by some primates.

Martin: Definitely, to reiterate what Brigitte says, there's a cause of bipedalism. And then there's the effect of having developed bipedal stance and one of the effects is that you are taller. If you come across a carnivore, it may be more frightened if you're standing. But I don't think that was a cause of bipedalism.

The real reason was for locomotion. If it hadn't been that none of the other effects would have followed -- like using arms for carrying -- babies, food, stones. Also, there's this idea that your body is less exposed to the sun -- also an effect.

So we became upright in the trees and when we came to the ground it was just easier to stay upright. And this brings me to yo-yo evolution, if you were upright in trees, and on all fours on the ground, you're putting a yo-yo into the evolutionary system. The same thing would happen if we put Orrorin as an ancestor of lucy and lucy of homo. You'd start with small teeth, go to big teeth in lucy, back to small teeth.

So you've got these yoyos and it's not impossible that it can happen -- but highly unlikely. Especially to occur in more than one instance.

Reading between the lines of that question, I think you thought we were on all fours and then went upright.

Ann Arbor, Mich.: What is Dr. Johanson's response to your hypothesis that Lucy is not our direct ancestor?

Martin Pickford and Brigitte Senut: Martin: Well we haven't spoken to him directly, but from what I"ve read, he's not very committed to it, but says Orrorin is a major discovery. Whether he thinks lucy is on the sideline or not, I don't know.

He even flew to Nairobi to see the original material, right after our team. From the e-mails I've had with him, he's very supportive.

Brigitte: John was one of the first people to congratulate us on the discovery and was very warm. And he was one of the first Americans to commit himself and we really appreciate it.

In science you can always disagree on interpretation -- which is necessary to keep science going. We all have resources and we all think differently. If we disagree I don't care as long as we can understand that it is science.

One thing we must not forget is that we may ultimately all be wrong or right, but the most important thing is the bone. We have to recognize and the public should know that we have all parts of the information, not all. TOmorrow could bring a new discovery that causes things to be rethought again. So we all actually have to rethink our positions and I'm very sorry that in anthropology that there are too many dogmas and myths. Science doesn't work with dogma. We just move forward -- it's the challege of all science.

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