Polynesian navigation snow. In the mid-20th century, Thor Heyerdahl proposed a new theory of Polynesian origins (one which did not win general acceptance), arguing that the Polynesians had migrated from South America on balsa-log boats. The presence in the Cook Islands of sweet potato that is a plant native to the Americas (called "kūmara" in Māori), which have been radiocarbon-dated to 1000 CE, has been cited as evidence that Americans could have traveled to Oceania. The current thinking is that sweet potato was brought to central Polynesia circa 700 CE and spread across Polynesia from there, possibly by Polynesians who had traveled
Thor Heyerdahl Heyerdahl obtained a radiocarbon date of 400 for a charcoal fire located in the pit that was held by the people of Easter Island to have been used as an "oven" by the "Long Ears", which Heyerdahl's Rapa Nui sources, reciting oral tradition, identified as a white race that had ruled the island in the past (Heyerdahl 1958). Heyerdahl further argued in his book "American Indians in the Pacific" that the current inhabitants of Polynesia migrated from an Asian source, but via an alternate route. He proposes that Polynesians travelled with the wind along the North Pacific current. These migrants