As a result, human parents must spend significantly more time holding and caring for their young to keep them alive or prevent deformational plagiocephaly, or flat head syndrome. They also gathered measurements from 385 human skulls from Japan dated from about 200 to 1,000 years old, 996 non-human great ape skulls, five fossilized Homo erectus skulls, and one fossilized Homo floresiensis skull. Back views of the skulls of a historical human (left) and a Homo erectus from Ngawi, Java (right: undated), exhibiting severe transverse deformational plagiocephaly. All of the human samples (modern or fossil) had a much broader range of deformation and head shapes. “Even though their brain size was much smaller, their newborn stage was already following the same kind of difficult process as larger-brained modern human ancestors,” said Kaifu.