 A second technique, using 3D microscopy, showed that the flesh had been removed from the bones using the same tools and techniques used on animal bones.According to Professor Chris Stringer of the Natural History Museum, this supports theories about cannibalism amongst the people living in or visiting the cave at that time.In February 2011, the same team published an analysis of human skulls of the same date found at the cave around 1987, which they believe were deliberately fashioned into ritual drinking cups or bowls.