The shape of this model comes from Mrs.Ples' cranium. Scientifically known as the ST5 skull, it belongs to the species Australopithecus africanus (which means southern ape of Africa). It was found at the Sterkfontein site, in South Africa. Mrs.Ples is estimated to be between 3.7 and 3.4 million years old, and has a cranial capacity of approximately 450cc (very small compared to our species, which has an average of 1300cc).