The Journals of Lewis and Clark

"It was a fantastic insight of Thomas Jefferson to create what he called the Corps of Discovery. These men went on this amazing voyage into the unknown, effectively from 1804 to 1806. Meriwether Lewis and William Clark, the two partners on this expedition, had basically no idea what they were going to find as they set off to the west of the Mississippi River. Everything in those days between the plains and the Pacific Coast was effectively unknown. It turns out that Jefferson was actually a palaeontologist. He didn’t call himself that. He was Mr President and so forth, but he had a lot of interest in these gigantic elephant bones that were being found in places like Kentucky. Clearly there weren’t any living elephants left in Kentucky and Massachusetts, but they didn’t know whether or not they might find these creatures alive as they went into the Rocky Mountains. So here we have this expedition that sets off into the complete unknown and we have this journal of the people that they meet. They encountered 72 American Indian tribes. They find and describe 200 plants and animals that are entirely new to science. They are setting off into a geography and a biology and an anthropology that was then just completely unknown. This is an analogy to what we are doing when we explore deep time, not in a geographic sense, where we are expanding our geographic knowledge. As we set off into the unknown past as palaeontologists, we want to find out what the world of the past was like. So, like Lewis and Clark, we are explorers with very little data. And like those past explorers, we have developed special tools to investigate the past. We have tools from the geological sciences that allow us to tell time. For example, where we work in Ethiopia is now a remote desert. When we look across the modern Awash River from sediment outcrops where we are finding these fossils, we see a great big volcanic mountain about 2,000 metres high. Three million years ago that volcano was not there. So you can’t go in thinking, “Well, Lucy must have seen that volcano.” We can find her bones and we can use volcanic horizons that accumulated through the eruption of other volcanoes to tell time, so we can calibrate what we find. Today we know that Lucy is 3.2 million years and Ardi is 4.4 million years old, so we are starting to build this sequence. What we wanted to do at the 4.4-million-year horizon was to get additional information on that lost world of the past. Even getting the information about what Ardi was like was completely fascinating because it turned out to be so unexpected. People had expected that we would find more and more chimpanzee-like things as we went back. But what we found is a creature that is not particularly chimpanzee-like. It is not entirely human-like either. It is unique. We would never have been able to find it unless we took this expedition into the past. Even if you look at something like its hand, it is fascinatingly complex. The palm is quite short like ours, and yet the fingers are very very long – like those of chimpanzees. When we look at the foot, the toe can grasp like all other primates. And yet the outside was built as a lever so that Ardi could walk on two legs. When we look at her head we find a braincase that is about the size of a chimpanzee’s but the face isn’t nearly so projecting. Her canines are short and blunt, and even the males in her species had very short canines. Support Five Books Five Books interviews are expensive to produce. If you're enjoying this interview, please support us by donating a small amount . Here is a creature that is new to science, which had never been seen before we found these bones. But what we wanted to do is say, “We have this creature which we can understand because we have the bones, but to really understand its biology, its ecology, its context, we wanted to take a broader look. Fortunately the horizon that we found her in takes us back to a very distant world of 4.4 million years ago, and we have animal remains, plant remains. We have the snails, we have the leaves, we have fossil wood, fossil pollen, we have fossil fish and fossil small mammals like mice and bats. We even have creatures that don’t exist any more. There is a gigantic bear that used to live in Africa. We have its remains, so we are able to accurately reconstruct the world of Ardi as it was then. We have built this knowledge and it becomes important because it shows us that she inhabited a place that was a woodland environment and that bipedality had already been established there. We used to think that this first came about as a result of opening up the savannas in Africa and that we are a savanna-adapted mammal – a kind of a chimp that became adapted to grasslands. And now the Ardi discoveries throw those ideas right out of the window."