“Lucy,” a truly iconic, prehistoric hominin fossil, is one of the most well-known scientific discoveries of our time, and for good reason. Known as Australopithecus afarensis, this 1974 Ethiopian find will be best remembered for revealing that she could walk upright – albeit somewhat inefficiently – meaning that bipedalism evolved at least 3.18 million years ago in our own species’ evolutionary lineage.
A remarkable new Nature study has shed some additional light on Lucy’s demise. Despite being one of the most complete fossilized hominin skeletons ever found, it’s not been entirely clear how she died, making her one of the oldest cold cases in prehistory. After a painstaking analysis of all her fractures, however, it appears she died falling out of a tree, outstretching her arms in an attempt to save herself as she took her final tumble.
“Up until this time, no one had ever before proposed a cause of death for Lucy,” lead author John Kappelman, professor of hominoid paleobiology and evolution at the University of Texas at Austin, told IFLScience.
As fascinating as this is by itself, it also appears to confirm something that some researchers have hypothesized for a while now: Lucy wasn’t just a ground-walker, but arboreal – a tree-climber. Her death, therefore, probably came about because, unlike her ancestors, she could not climb trees as well anymore, and slipped and fell.
“Our new hypothesis offers indirect support for this idea,” Kappelman added. “How much time, and how frequently did the climbing occur, well, we don’t know at present. But let’s assume for a moment that Lucy did nest in the trees at night to avoid predators, just as chimpanzees do.”
Lucy's distal radius (wrist) undergoes X-ray (CT) scanning. Marsha Miller, UT Austin