Lucy the australopithecine

The story

A morning in the Afar desert

On the morning of 24 November 1974 the American Donald Johanson and his student Tom Gray left camp to check an area of Hadar, in the Afar desert in Ethiopia. It was already hot. On the side of a small gully Johanson noticed a fragment of bone sticking out of the earth: an arm bone. A little further on there was a piece of skull, then a rib, then part of a thigh bone and a jaw. They were bones from a single creature, not scattered by animals as so often happens. Over the next two days the whole team combed the slope and recovered hundreds of fragments: about 40 per cent of a skeleton, a very rare exception for fossils so old.

That evening the camp celebrated. A Beatles song, “Lucy in the Sky with Diamonds”, was playing on the radio, and someone suggested the name. The skeleton, catalogued as AL 288-1, became Lucy to everyone. In Ethiopia she also has a name in the Amharic language, Dinkinesh, which means “you are marvellous”.

What Lucy was like

Lucy was an adult of the species Australopithecus afarensis, “southern ape of the Afar”. She lived about 3.2 million years ago. She was a little over a metre tall and weighed perhaps thirty kilograms: a small creature with rather long arms, a brain of about 400 cubic centimetres (a third of ours) and a face with a jutting jaw. Her pelvis and legs clearly show that she walked upright. Her curved fingers and her long shoulders and arms are a reminder, though, that she could climb trees well, and perhaps slept and took refuge in them.

An even older clue to this way of walking had been the footprints of Laetoli, in Tanzania: a long trail of prints left about 3.7 million years ago in wet volcanic ash, made by individuals of the same species. They were discovered between 1976 and 1978 by Mary Leakey's team. Lucy now gave a body to those footsteps.

Why it made such a stir

Until then many scholars thought our ancestors had started to walk upright after they had developed a big brain. Lucy showed the opposite: her body was already almost human in the legs, while her head was still ape-like. So the order was: feet first, then brain. The find had worldwide echoes and put palaeoanthropology on the front pages.

The following year, in 1975, in the same place, the team found in a single spot the remains of at least thirteen individuals: the so-called “First Family”, perhaps a group that died together. Other discoveries in Ethiopia told the story of how these beings grew up: in 2000 at Dikika a girl of 3.3 million years ago was found, called Selam (“peace”), with her bones still almost intact. The name Lucy, however, remains the most famous.

Lucy after the discovery

The original skeleton is kept in the National Museum in Addis Ababa, Ethiopia, and is rarely shown; visitors to the museum usually see a copy. Between 2007 and 2013 the original remains travelled to the United States for a big exhibition, a much-debated decision because fossils are fragile. In 2016 a research group at the University of Texas, examining the fractures in the bones with tomography, suggested that Lucy died by falling from a tall tree. Other scholars think instead that the fractures happened after death, from the weight of the sediments. As always, science leaves the doubt open.

Lucy's place in the family tree is not certain either. For decades it was thought that A. afarensis was an ancestor of our genus Homo. Today many people more cautiously consider her a close relative of the species Homo came from, because the dates and the most recent fossils leave room for more possibilities. To understand such a distant age, new fossils matter a great deal: every digging season can change the story.