Hypsicranic skulls are characterised by the skull height reaching at least 75 percent of the skull length. This is also called high-skulled. Hypsicranic individuals often have a flat occiput (planoccipital). Although rare in prehistoric times, hypsicrany is widespread today and occurs in most East and South East Asians. It is particularly strong in some Indochinese and Malay groups. Another centre of hypsicrany lies in the Caucasus, Anatolia, and the Balkans. In a somewhat less pronounced form it extends through Russia. Some African savannah groups and populations at the Gulf of Guinea show hypsicrany as well, but usually not in a very pronounced form. In America hypsicrany is strong in some groups native to the Southern US states and in peoples of the Andes. In milder forms it extends through Amazonia, Patagonia, and many parts of Central America.