Lucy Found in Ethiopia

In 1974, a team working in the Afar region of Ethiopia uncovered about forty percent of the skeleton of an early human relative, an individual of the species Australopithecus afarensis. Nicknamed Lucy, the fossil is roughly 3.2 million years old. It was one of the most complete skeletons of such an ancient hominin ever found, and it offered striking evidence that our ancestors walked upright long before they developed large brains.

The discovery grew out of decades of fieldwork in East Africa, where erosion exposes ancient sediments rich in fossils. By the early 1970s, researchers had already found important hominin remains at sites such as Olduvai Gorge and Lake Turkana, but the picture of human origins was patchy. The International Afar Research Expedition, organized by Maurice Taieb, Donald Johanson, and Yves Coppens, was surveying the Hadar area, where river and lake deposits had been cut into gullies and badlands. Many scientists at the time assumed that big brains and upright walking had evolved together, and fossils older than about three million years were scarce.

Johanson and a student, Tom Gray, spotted the first fragments of arm bone on the surface in late 1974. Further searching turned up pieces of skull, ribs, vertebrae, pelvis, and leg bones, all apparently from a single small adult. The pelvis and the angle of the knee joint pointed clearly to bipedal walking, while the skull was small, with a brain not much bigger than a chimpanzee's. The nickname came from the Beatles song "Lucy in the Sky with Diamonds," which was reportedly playing in camp during the celebrations. In Ethiopia the skeleton is also known as Dinkinesh, meaning "you are marvelous" in Amharic.

Lucy was formally described in the late 1970s as part of a new species, Australopithecus afarensis, which included other fossils from Hadar and from Laetoli in Tanzania, where fossilized footprints of similar age show upright walking. The find helped establish that bipedalism came first, with brain expansion following much later. Lucy was small, standing perhaps a little over a meter tall, though her long arms and curved fingers suggest she may still have spent time climbing trees. How much she did so remains debated.

Lucy's exact place in the human family tree is also debated. Many researchers regard A. afarensis as close to the ancestry of the genus Homo, while others see it as a side branch. Later discoveries, including older hominins such as Ardipithecus, have extended the story further back. Even so, Lucy remains among the most famous fossils in the world, a symbol of Ethiopia's role in human origins research, and the subject of ongoing study and public exhibition.