Human remains have been found which have been dated to about 50,000 BC although this is an estimate. These ancient inhabitants probably migrated from Southeast Asia, from people whose ancestors had originated in Africa 50,000 to 70,000 years ago. New Guinea was one of the first landmasses after Africa and Eurasia to be populated by modern humans, with the first migration at approximately the same time as that of Australia.
Agriculture was independently developed in the New Guinea highlands around 7000 BC, making it one of the few areas in the world where people independently domesticated plants. A major migration of Austronesian speaking peoples came to coastal regions roughly 500 BC. This has been correlated with the introduction of pottery, pigs, and certain fishing techniques. More recently, in the 18th century, the sweet potato was taken to New Guinea, having been introduced to the Moluccas from South America by Portuguese traders, representing the locally dominant colonial power. The far higher crop yields from sweet potato gardens radically transformed traditional agriculture; sweet potato largely supplanted the previous staple, taro, and gave rise to a significant increase in population in the highlands.
Although headhunting and cannibalism have been practically eradicated, in the past they occurred in many parts of the country as part of ritual practices. For example, in 1901, on Goaribari Island in the Gulf of Papua, a missionary, Harry Dauncey, found 10,000 skulls in the island’s Long Houses. According to the writer Marianna Torgovnick, "The most fully documented instances of cannibalism as a social institution come from New Guinea, where head-hunting and ritual cannibalism survived, in certain isolated areas, into the fifties, sixties, and seventies, and still leave traces within certain social groups."
Little was known in the West about the island until the 19th century, although Portuguese and Spanish explorers, such as Dom Jorge
