Archaeological evidence suggests that early hominids inhabited China 2.25 million years ago. The hominid fossils of Peking Man, a ''Homo erectus'' who used fire, were discovered in a cave at Zhoukoudian near Beijing; they have been dated to between 680,000 and 780,000 years ago. The fossilized teeth of ''Homo sapiens'' (dated to 125,000–80,000 years ago) have been discovered in Fuyan Cave in Dao County, Hunan. Chinese proto-writing existed in Jiahu around 7000 BCE, at Damaidi around 6000 BCE, Dadiwan from 5800 to 5400 BCE, and Banpo dating from the 5th millennium BCE. Some scholars have suggested that the Jiahu symbols (7th millennium BCE) constituted the earliest Chinese writing system.