Although the skull of the early Homo sapiens and that of today's modern man differ in their form, their thinking organs are roughly the same size and rounded. The research team around Christoph Zollikofer from the University of Zurich reports on this in the journal "Proceedings of the National Academy of Sciences".
What shape the brain of our human ancestors had 160,000 years ago has been debated so far: instead of a round head, Homo sapiens had a wide, elongated skull with a rather elongated face; and experts suspected that the brain had a silhouette similar to the bone. A common hypothesis is that the thinking center has evolved greatly in its function and subsequently in its form over the past 200,000 years. As a result, the surrounding skull also took on a corresponding shape.
The researchers reconstructed the skulls of a child and an adult who came from the Ethiopian excavation site Herto and were around 160,000 years old. In addition, they analyzed several skull finds from the sites of Qafzeh and Skuhl in Israel, which dated around 100,000 to 120,000 years. The 3-D models of the fossil skull then compared them with 125 skull recordings of today's people. They made use of the fact that human brain growth has been practically complete when the first permanent molars appear in childhood. The facial and skull base bones, on the other hand, continue to grow into adulthood.
The team led by Zollikofer found that the infantile skull bones of the early Homo sapiens specimens and the heads of today's children were shaped similarly - at a time when their brain growth had already been completed. The deviating skull shape only developed subsequently. Probably, the researchers conclude, this deviation is due to differences in diet and lifestyle: softer foods are easier to chew and require less jaw work. A corresponding diet may therefore be associated with smaller faces and rounded skulls.
