Lucy’s death was caused by a 12-meter-tall tree. The most famous Australopithecus died of a sudden fall, confirming the thesis of an arboreal hominid.
Lucy has never worn her name so badly. Australopithecus, which takes its name from a Beatles hit (Lucy in the sky with diamonds), has fallen heavily from the top of a tree. It was by hitting the ground that our ancestor lost his life. After four decades of doubt on the subject, an American team decides in favor of this hypothesis in the journal Nature. John Kappelman and his colleagues solve one of the most debated elements in passing: the first hominian did well in trees.
Lucy’s fossil, discovered in 1974 in Ethiopia’s Afar region, still holds many secrets. The Texans team helped elucidate at least one. During a visit to the United States, the skeleton was photographed from all angles using a high-performance scanner. A justified interest: “It is one of the most complete skeletons; as such, it provided us with a lot of information on the first men, ”recalls John Kappelman.
“Feet first”
The photos revealed elements on Lucy’s life… but also on her brutal death, to say the least. As with all fossils, three million years of exposure to the elements have left its mark. But some are suggestive of injuries that occurred during the lifetime of the world’s most famous Australopithecus.
One particularly attracted the attention of researchers, at the level of the humerus. She shows signs of compression but the fragments remained attached to the body. “This suggests that the bone envelope and joint capsule were intact at the time of the injury,” John Kappelman analyzes. The absence of healing corroborates this hypothesis.
Lucy would therefore have fallen from a height of 12 meters, at a speed of about 60 km / hour. The location of the fractures seems to confirm this: foot, hip, ribs, shoulders and mandible are injured. “She probably landed feet first. The injuries we see to the knees suggest that his body has twisted to the right, ”says John Kappelman.
Source : KAPPELMAN NATURE
Biped and arboreal
Conscious at the time of her fall, Lucy did everything to cushion the shock with her arms. But at 60 km / hour, difficult to mitigate the impact on internal organs. “Death followed very quickly,” says John Kappelman. The co-director of the mission who discovered Australopithecus, Yves Coppens, find nothing to complain about.
Lucy was therefore bipedal and arboreal: this work confirms that the hypothesis had been debated since its discovery. Like current monkeys, it would have taken shelter in trees at night, to escape predators. But the very fact of having become bipedal seems to have handicapped our ancestor and his congeners. Less skillful in trees, because of this evolution, it would have been more prone to falls.
Watch the explanation from the Texas team:
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