Evidence for hominid evolution between 5.5 and 2 million years ago comes only from Africa, although earlier, Miocene, ancestors of apes and humans are also found in Asia. On present knowledge it seems that Homo evolved from the Australopithecines in Africa and that H. erectus colonized parts of Asia by 1 million BC.
Recent finds from East Asia of H. erectus may upset this picture as they have a claimed date of 1.8 million years ago (mya), the same age as the earliest H. erectus fossils in Africa.
East Asian H. erectus had adapted to an environment far cooler than that of Africa: they used fire for warmth and sheltered in caves, of which the best known is Zhoukoudian.
This cave, occupied around 450,000-350,000 BC, has yielded many H. erectus skulls, some broken open at the base to remove the brain. Also found in the cave were the remains of hackberries and other plants eaten by its occupants: such evidence is rarely preserved.
Many stone tools were also recovered. Unlike those of Africa, West Asia and Europe, among which handaxes were a principal component, the toolkits of eastern H. erectus were mainly flakes and chopping tools made on cores; this probably related to the coarse materials available, unsuitable for making handaxes. Some scholars suggest bamboo was used instead of stone for many tools in the areas in which it was available.
