On November 24, 1974, American paleoanthropologist Donald Johanson planned to stay in camp to catch up on his field journals. He was in the Great Rift Valley in Ethiopia on an extended surveying mission where he and his multinational team were searching for the fossilized bones of early humans and their ancestors. Instead of staying in that day, Johanson was convinced by a graduate student to go out into the blazing sun and search yet another section of ground. While their planned excavation proved fruitless, on his way back to the car Johanson spotted a bone fragment in a small gully. He and his team went to work carefully removing this fragment, and the more than 30 other fragments that would come to comprise one of the most important set of remains found to date: Lucy.
When we glimpse into the distant past and try to better understand the origins of our Homo sapiens species, the view is murky at best. For the vast majority of history, our lineage is entirely shared with the chimpanzee. That is, of course, until it wasn’t anymore. Our development branched off, probably around seven million years ago, and evolved into a new line of more earthbound and upright creatures. Lucy, who was named by Johanson for the repeating recording of The Beatles’ Lucy In The Sky With Diamonds that played as the team unearthed her bones, is a member of the family Australopithecus, the progenitors of the family Homo, to which we belong. As best as they can tell from the bone fragments discovered that day, Lucy stood around three and a half feet tall and easily walked on two legs. Much else beyond that is open to interpretation.
The trouble with Lucy, and with most other fossils from around this time, is the relatively incomplete nature of the skeleton and the scarcity of comparators. Johanson triumphantly announced, via his own figuring, that Lucy represented about 40% of a complete skeleton. While anthropologists argue about this number, it cannot be argued that Lucy is lacking what evolutionary biologists would agree were her most interesting features: hands, feet, and skull. Only a few skull fragments were found, meaning it’s highly difficult to get a good understanding of how large her cranium, and brain, would have been. And the hands and feet, which would provide a deeper insight into how adept she was at climbing and walking, are sorely lacking as well. Even the question of gender, which Johanson was quick to proclaim as female due to the dimensions of the pelvis, is still hotly debated and far from certain. While other skeletons have been found from the Australopithecus family, they represent millions of years of history and development among them, and trying to piece together a single, cohesive narrative is tricky, if not entirely impossible with the information at hand.
The most complicating factor for extrapolating meaningful information from these finds has to do with the process of evolution itself. Like smoke rising from a flame and searching for a path to the outside, the procession of evolution is filled with many paths, but only one that leads to success. In this period between chimpanzees and hominids, the australopithecines did not develop in an orderly progression, but rather followed branches of differing evolutionary advancements. Some of these proved futile and the branch went extinct, while one prospered and led, eventually, to humans. The trouble with pulling meaning out of the bones of Lucy is that without much more information and many more specimens with which to construct a better picture of these developmental paths, we can never be certain whether Lucy was part of the path that led to us, or one of the many that ultimately failed. And so while Lucy may provide us a glimpse into our ancestral past, she may also just be an example of the type of creature that once roamed the Earth. Either way, it is still a truly exciting idea that we are able to physically study something that lived over three million years ago, a stretch of time nearly beyond comprehension.