One of the oldest and most complete human ancestors, Lucy, probably died from a fall from a tree. The upright hominin has fallen from a height of about 15 meters, according to the researchers. They write that this week in Nature. But not everyone agrees with that conclusion.
Lucy was found in 1974 by paleontologist Donald Johanson and his student Tom Gray near Hadar, northern Ethiopia. She is named after the song Lucy in the sky with diamonds by the Beatles, a big hit at the time. Eventually, the discoverers were able to excavate about 40% of her skeleton and she is now considered one of the oldest (3.18 million years) upright walking ancestors of humans that have been found.
She belonged to the species Australopithecus afarensis and she is central to the debate among scientists as to whether her species still lived in trees. According to the latest study, published Aug. 29 in Nature, Lucy hadn't forgotten climbing and may have been sleeping in trees at night. Until one day she fell out and took her blow with her outstretched arms. This is what John Kappelman and colleagues concluded after intensive research into 35,000 CT scans they made of Lucy's skeleton.
By taking CT scans, they did not damage the valuable skeleton, but they were able to study the various bones in detail. And in doing so, they noticed that Lucy's right humerus was broken and splintered. According to the research team, which included an orthopedic surgeon, the fracture cannot have occurred after her death, because then the bone fragments would have been scattered on the ground. That was not the case:the splinters were still in the bone.
Thus, the bone must have splintered when the joint capsule of the shoulder was still in place. In addition to the arm fracture, the researchers discovered many other fractures, including her neck and pelvis. Because the bones show no signs of healing, the fractures found must have been fatal to her, the scientists say. How this was possible can be seen in the reconstruction below, which the scientists made.
Reconstruction of Lucy's fatal fall.
The injuries found are very similar to those of patients who make a serious fall and catch it with outstretched arms. The scientists calculated that Lucy must have fallen from a height of 15 meters, probably from a tree. Hadar, Lucy's site, consisted of woodland with fairly tall trees. The biggest fractures are on her right side, so she probably took the hit with that side. The research team suspects that the physical adaptations to walking upright made the species less good at climbing. Yet they were presumably better at it than modern humans. For example, the species had long, strong arms and curved fingers. Possibly the small humanoid (Lucy was 1.1 meters) only used the trees as a nighttime shelter, just like chimpanzees do.
Comment
The Ethiopian National Museum provides scientists with access to all 3D files created from Lucy so that they can evaluate the researchers' hypothesis. It will probably still happen, because the first comment has already been made. This is what Donald Johanson, the discoverer of Lucy, told the Guardian that there is no proof that Lucy fell from a tree. Tim White, an American paleontologist, says in the same piece that the fractures found are part of the normal damage that occurs to fossils. In addition, he thinks that the researchers describe the fractures that suit them. According to him, there is much more damage to Lucy's bones, which they do not explain. Further research will have to show how it works exactly.
Extensive report on the research.