Richard Leakey talks family and great discoveries

Richard Leakey (Courtesy Leakey Foundation)

On July 17, 1959 paleoanthropologist Mary Leakey discovered a fossilized skull from a previously unknown species of hominid that she and husband Louis Leakey named Zinjanthropus boisei. The 1.75-million-year-old fossil from Olduvai Gorge, Tanzania, turned the Leakey's into household names, and firmly established that the roots of the human family tree extended deep into antiquity. The name of the genus "Zinjanthropus" has since been dropped. Whether the fossil belongs to the genus Australopithecus along with its smaller cousins, Australopithecus afarensis and A. africanus, or deserves to be part of a separate genus called Paranthropus along with other large hominid species like Paranthropus robustus has been the subject of debate. Some population of the smaller, or gracile, Australopithecines were the ancestors of Homo habilis, Homo erectus, and eventually Homo sapiens, while Paranthropus was probably an evolutionary dead end. Whatever genus the fossil is assigned to, it is no longer believed to be a direct ancestor of modern humans, but one of a number of hominid species that lived in Africa millions of years ago. In honor of the 50th anniversary of this discovery, ARCHAEOLOGY Senior Editor Zach Zorich interviewed Mary and Louis's son Richard Leakey who still conducts paleoanthropological research in Kenya along with his wife Meave and daughter Louise. In addition to his scientific career, Richard is also an influential figure in Kenyan politics and wildlife conservation.

What was happening on the site when your mother, Mary Leakey, made the discovery of Zinjanthropus boisei? Do you remember what you were doing when the discovery was made?

Well, I only got there two days after the discovery. They had gone down to Olduvai to excavate this site where they had found a hominid molar the year before. My father was optimistic that if they excavated the site they would find additional fragments of whatever the molar came from. And they had arranged for somebody to take photographs of the excavation with the hopes that if they did find something this would lead to a magazine article. Of course, the photographer was delayed by two days and they were simply killing time and my mother was off looking around for anything else she could find. I was with the photographer, and when we arrived in camp we were told that plans had changed and we had something really important to film.

What happened next?

We got there quite late in the evening, so the next day we went down and my mother and father started to work on uncovering parts of the palate. The palate was broken into two pieces. The early photographs show them working carefully and very close to the palate, which was split in two but still had all of its teeth, and I just sat around and watched and the photographer took lots of pictures and they recovered the palate and then they realized there were a few fragments of skull so it was then decided to take some weeks to excavate and see if there was anymore of this skull. On the third day, we left them to take photographs of wildlife on the Serengeti. I was helping the photographer and we came back after ten days, I think, to find that they had indeed assembled a large part of the skull. We spent a few days photographing them with the skull and putting it together. All those early pictures you see published in the first National Geographic article in 1960 were taken at that time.

Were you very involved with the excavations at Olduvai Gorge at that point?

No, no, no. I was in my mid-teens and I was there to help run errands in the camp but it was a very small operation and without any training or skill I certainly wouldn't have been permitted anywhere near the excavations.

When did you first become involved with the fieldwork?

Well, I never did any fieldwork at Olduvai. I helped on school holidays sorting bones, cataloging, and fetching water for the camp and that sort of thing I spent a lot of my early teens in that area. I didn't really do anything at Olduvai. My first attempt at looking for fossils was at a site to the east of Olduvai called Lake Natron. We took a couple of cars up the shore of Lake Natron found a place my parents were aware of called Peninj and Kamoya Kimeu?, who would later worked for us at Lake Turkana. He spotted a mandible of Australopithecus boisei, and that then led to my return there in '64. I became increasingly interested and decided to make a career in the field.

How did discovering Zinjanthropus boisei change life for your family?

I think, clearly, looking back and remembering discussions, it gave my father and mother for the first time some international recognition for the work at Olduvai, they had had great recognition for their work 10-15 years earlier at Rusinga with Proconsul [a species ancestral to great apes and humans, which lived 18 million years ago]. But my father was able to attract more funds. I'm mean, not a great deal of funds but sufficient funds for 3-4 month expeditions, and they were able to buy a Land Rover. They were able to build a camp that was a little more comfortable than what they had had for the previous 30 years. People started to pay much more attention to my mother and father. I think that, if you will, launched them in a much more substantive way than their earlier work had launched them in the late 1940s and 50s.

In terms of your day-to-day life did it have much of an impact?

Not much, no. I mean, my father ceased to work at the Kenya museum in 1962 or 1963 and began to focus his interests in primatology, Jane Goodall and things like that. So, no. It changed the fact that my mother and I spent most of our time at Olduvai and my father was spending part of his time at Olduvai and part of his time in Nairobi but no longer doing administrative duties around the museum but focusing more on primates and raising support for the work at Olduvai.

When Mary found the Zinj specimen there was a controversy over whether it deserved its own species. There were some researchers who wanted to lump it with Paranthropus robustus and even today there seems to be debate over whether it should be Australopithecus boisei or Paranthropus boisei.

I think these are separate issues. I think everyone agreed it was a new species of either Paranthropus or Australopithecus. The argument about Paranthropus or Australopithecus is still very much in its early days. Nobody questioned that it was a species, "boisei." The question was "what was its generic ranking." My father--supported by Phillip Tobias and others at the time--felt it was so different in its robusticity and so different in any forms that it should warrant a separate generic rank. That's why they called it Zinjanthropus and later it became known as Australopithecus [Zinjanthropus] boisei. I think in the last decade so much material has been found in East Africa that the time span of this taxa goes from 1.3 back to 2.5 million years ago. I think the majority of people now feel that Paranthropus is a better generic label than Australopithecus, which seems to be different, but I don't think it is a closed case at all. There will be a meeting later this year here in Kenya to commemorate the 50th anniversary of the discovery of Zinj and the status of Paranthropus versus Australopithecus will be discussed.

Why do you think Paranthropus is a better generic label than Australopithecus?

Well, it's not so much what I think, it's consensus. A lot of arguments to be made by people like Bernard Wood who's in Georgetown University in D.C. and Fred Grine at Stony Brook University.

What has been learned about Paranthropus boisei over the past 50 years?

Well remarkably little funnily enough. Nobody ever found post-cranial bones associated with the skulls, so we don't know the limb bones. We presume they walked around like we do, but there's no definitive collection that has associated the head with the legs and the arms. There are various post-cranial elements that are assumed to belong to a large hominid such as boisei because of their thighs and their distinctiveness from Homo erectus with which it was contemporary. But I suppose one of the big prizes out there for somebody to get--finding definitive evidence of the bipedal adaptation of Paranthropus and what its body shape and body mass would be, which you can't learn from skulls and jaws.

Have there ever been stone tools found in association with Paranthropus boisei?

Well I mean, that was the first, if you like, error when they found Zinj 50 years ago. The fragments of the skull were associated with masses of artifacts and masses of bones that had clearly been butchered and my father, at that, time was unaware that there were two taxa of hominids around because Homo habilis had not been found and he assumed they had found the tool maker because at that time it was seen as a single step-by-step progression from something like a Zinj through to something like us. So, Zinj was the earliest but I think one of the most important things that the work at Olduvai provided, and it didn't provide it in '59 but a year later, was its context involved the possibility of dating through potassium-argon and later argon-argon radiometric dating and for the first time the very considerable antiquity of early hominids was established. When Zinj was found, it was assumed that it was probably half-a-million years old. When the dating was done it turned out 1.75 million. I think that's what excited the world--the great antiquity of the human story--and got people who had been mildly interested much more curious about what had happened over this long period of time. Then with more money and longer expeditions, they found Homo habilis and the story began to get quite interesting and complicated. That early work at Olduvai launched the second generation of major interest in the origins.

So the tools that were found in association with boisei were later attributed to Homo habilis.

Well, they are still looking to attribute both taxa with tools, and there are other people, like me, who don't believe that you could have that parallelism if the adaptation was survival in a very challenging environment. So, it's more likely that the larger-brained, more human like form [habilis] made the tools, but if there were more than one species how would you know, if the tools were all the same? So, we don't know.

What do we know about boisei's diet?

Well again, one hasn't got a very clear picture, but the general sense is that the teeth are adapted for a fairly coarse, largely vegetarian diet that required a lot more grinding than cutting, and the teeth wear flat very quickly. We found many specimens since that when the third molar is erupting you see the first and second molar is already worn down to below its dentin. I think the consensus still is that they were coarse vegetarian eaters, largely, but you know gorillas in central Africa eat termites and bugs and things too, not strictly vegetarian like a mountain gorilla. They were omnivorous, but with a bent toward leaves and berries.

Zinj was the first fossil that was securely dated. What impact did that have on archaeological science at the time?

Well I think it...to be honest, I can't really say because I haven't really looked at it in a historical context. But, what I do know is it tripled the time span that something approaching a human ancestor had been around, which surprised everybody. Secondly, the antiquity of its associated animal fauna was greatly extended backwards. And it then raised a number of questions about other finds because it had been dated within the scheme of the last half-a-million years like the South African finds. People began to ask questions as to whether South African A. robustus or A. africanus or Paranthropus--whatever you want to call those things--was in fact the same age or whether the differences between them was one was earlier and one was later and this has continued to be debated because the South African fossils don't come in places where you can get such precise dates by the same techniques.

What has been the lasting impact of the Zinjanthropus discovery?

Well, I think it produced a public interest and funding largely from the public, not governments, but National Geographic and private foundations that enabled work not only to be extended and expanded at Olduvai but then raised such an interest that we could start to find money for other projects like the one at Lake Turkana which I launched in 1968, the one that started the year before that in the Omo valley with Clark Howell and the French and I think it just generated huge public interest in this subject and with huge public interest donors usually turn up. I think the excitement around Zinj launched an era that is still running today where people are just hungry for more information about how we came to be and what we were over this incredibly long period of time.

What do you think the next 50 years are going to hold for the Leakey family and paleoanthropology?

I think they are quite separate issues. Who knows what will happen to the Leakey family, my daughter is in paleoanthropology and vertebrate paleontology, Louise, but what she does with her career, time will tell. She is interested to see the work continue at least in the Turkana area. I think you are going to see a convergence of information from molecular biologists and geneticists tying into the fossil record. I think you are going to get a lot more information out of the fossils using new techniques that can interpret what the shapes and sizes lumps and bumps actually mean. I think you are probably going to be able to extract a lot more information by techniques that weren't available 20, 30 years ago.

Many more fossils will be found, and new sites will be found. I think within 50 years we will certainly know what Paranthropus was and whether it was significantly different in South Africa and East Africa. What H. habilis was and what its ancestors were. Of course, the big question is what about us? The story of humans is very poorly known. It appears all modern people in the last 65,000 years descended from a single ancestral population, yet Homo sapiens has been around 50 times that amount of time. What happened?

I think there will be a huge increase in information in the next 50 years. Hopefully, it moves paleoanthropology to a position where it is not a take-it-or-leave-it situation where fundamentalist Christians and Muslims can say "we don't believe it, 'cause there's not enough evidence." I think the story of our origins will be taught like mathematics, and chemistry, and physics. There will be far more un-arguable facts.

What will be the place of the Turkana Basin Institute and your other research projects in moving this science forward?

I hope it will be Kenyan-focused for paleontological and archaeological studies around not only humans but the associated faunas that over the next 50 years will provide a large part of the answers to the questions you've been asking me. It should become a major international research base that scientists from many countries will be able utilize in a coordinated way. That's the plan.

What are some of the research questions you will be taking on?

Well you know, where did Homo sapiens really come from? What started agriculture? Why didn't earlier Homo sapiens succeed? Why was it a later population? Does this apply in any way to biological adaptation, which you don't see in the fossil record? What is the role of climate change in producing various critical stages in evolution? When did bi-pedalism establish itself? Was it once or several times? What is the relationship between Paranthropus and Homo? How far back does it go? What was the common ancestor? Where did that come from? Where did the great apes come from? What was the ancestor of great apes? When did they start? And what drove them in to existence in an evolutionary context? So there are many question of that kind that could be answered.

If you had to choose one question about human origins you would like to see answered what would it be?

Today?

Yes.

I want to know when and under what pressures bipedalism developed.

Why do you see that as the key question?

Well for me personally, it marks the beginning of everything else that happened in terms of events that led to "us." Without having hands free for support, a big brain wouldn't have done us any good. Anymore than it does a dolphin any good.

You mentioned your daughter Louise is following in your paleoanthropological footsteps...

Not in my footsteps. She is in the same profession. [chuckles]

Ok, How is her approach to science different from yours?

Well, she went and studied the subjects in college and University and got her Ph.D. I studied at the feet of my parents and their friends and never went to college at all.

That was something you had in common with your mother, Mary. Is there a family tradition there...

No, it was quite, quite, quite accidental. In my mom's case she got thrown out of school very early on and never wanted to go back, and became hugely interested in archaeology. I threw myself out of school and didn't want to ever go back and didn't want to do archaeology at all. There was no connection between her career and mine whatsoever in terms of any decisions it just happens to have worked out that way

Are there any fossil hunting techniques that have been passed down through the generations of Leakeys?

I seriously doubt it. I think we have been very lucky to live in a country where there is so much to be found. We've had an interest in it. Different generations have benefitted from previous generations knowing where to find things and how to find them. It's sort of in the family culture but I don't think there is any more to it than that.

There are no tricks of the trade that you pass down?

No, no, no. I don't think so.

One last question, what has been the greatest fossil hominid discovery since Zinjanthropus and why?

Well, I think, in some ways the Turkana Boy, Homo erectus, was. And I think it was the most important since Zinj because it provided so much more information than just a skull and teeth. It had limb bones, which enabled us to look at limb bones from other taxa. It was sufficiently complete that I think even right-wing fundamentalists had to concede that it is remarkably human and all they can question is its age. I think it was a very solid nail in the plank against creationism. I think more needs to be found, but I think it was a major, major milestone in persuading people that we weren't making this up on bits and pieces, but there were in fact human looking skeletons 1.6 million years ago.