“Limb bones are heavy and they dropped to the bottom of whatever water was moving them, but the skulls float.
“Where burials were in terraced deposits, once water eroded them out the skulls seemed to separate from the limb bones,” Ciochon says. “Limb bones are heavy and they dropped to the bottom of whatever water was moving them, but the skulls float. That may be why the skulls at Ngandong ended up separated from all but two of the long bones.”