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 the late 1990s, genetic testing found that the mitochondrial DNA of the Polynesians is more similar to people from Southeast Asia than to people from South America, showing that their ancestors most likely came from Asia. Anthropologist Robert Carl Suggs included a chapter titled "The Kon-Tiki Myth" in his 1960 book on Polynesia, concluding that "The "Kon-Tiki" theory is about as plausible as the tales of Atlantis, Mu, and 'Children of the Sun.' Like most such theories, it makes exciting light reading, but as an example of scientific method it fares quite poorly." Anthropologist and National Geographic Explorer-in-Residence Wade Davis