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Four decades after the discovery of Lucy, her remains are quite possibly the most famous discovery in paleoanthropology and one of the more important. The impact of finding a nearly entire skeleton from a 3.2 million year old hominid revealed a lot about human evolution. We’ve learned a lot from Lucy, from biophysics to the geological environment she lived in. Up until recently, however, her cause of death was unknown to us, until now.

John Kappelman, a paleoanthropologist at the University of Texas at Austin, with 3-D printouts of Lucy’s skeleton. Credit Marsha Miller/University of Texas at Austin

John Kappelman, a paleoanthropologist at the University of Texas at Austin, with 3-D printouts of Lucy’s skeleton. Credit Marsha Miller/University of Texas at Austin

Almost 10 years ago, Lucy went on tour. While at the University of Texas at Austin, a team put her through a CT scanner and conducted a sort of forensic and paleontologic experiment. Their findings were published in Nature, last week. The team discovered she sustained a compressive fracture, which was confirmed by consulting multiple orthopedists. Lead author, Kappelman, looked at the remainder of the skeleton and found more compressive fractures along with greenstick fractures. The scientists concluded that she came down feet-first and then tumbled forward, holding out her hands in a futile hope of protecting herself. The fractures to her rib cage suggest crushing injuries to her internal organs that would have killed her.

An image from a video animation depicting a hypothetical scenario for Lucy’s fall out of a tree. Credit Valerie Lopez/John Kappelman

An image from a video animation depicting a hypothetical scenario for Lucy’s fall out of a tree. Credit Valerie Lopez/John Kappelman

Dr. Kappelman and his colleagues hypothesize that Lucy must have fallen from a tree because geologists have determined about the environment where she lived, at the time, was a low-lying wooded area around a stream, with no cliffs nearby. While this is certainly a plausible scenario, many paleoanthropologists are skpetical. Some of the most vocal critics, like Ericka N. L’Abbé, a professor of anthropology at the University of Pretoria in South Africa, and even Dr. Johanson, the man who discovered Lucy, state the fractures could have occured post mortem, not perimortem. In order to truly identify if these fractures happened after death, microscopic evaluation of the fossils would be needed to done.

One of the most important features of Lucy was per bipedal stature, especially her lower extremities and her pelvic girdle. But she still was a tree climber. Last monnth’s discussion in Nature finding considers the possibility that Lucy fell out of a nest in which she was sleeping, like Chimpanzees, or while she was climbing for food.

If you have a 3D printer, you can jump on over to eLucy.org, to download the renderings and even print out casts of Lucy’s bones on 3-D printers.