Polynesia of the plant in the Cook Islands have been radiocarbon-dated to 1000, and current thinking is that it was brought to central Polynesia c. 700 and spread across Polynesia from there, possibly by Polynesians who had traveled to South America and back. Thor Heyerdahl proposed in the mid-20th century that the Polynesians had migrated from the northwest coast of Canada by large whale-hunting dugouts, and from South America on balsa-log boats. Many anthropologists have criticised Heyerdahl's theory, including Wade Davis in his book "The Wayfinders". Davis says that Heyerdahl "ignored the overwhelming body of linguistic, ethnographic, and ethnobotanical evidence, augmented
Kon-Tiki expedition mounting the "Kon-Tiki" expedition was to show, by using only the materials and technologies available to those people at the time, that there were no technical reasons to prevent them from having done so. Although the expedition carried some modern equipment, such as a radio, watches, charts, sextant, and metal knives, Heyerdahl argued they were incidental to the purpose of proving that the raft itself could make the journey. The "Kon-Tiki" expedition was funded by private loans, along with donations of equipment from the United States Army. Heyerdahl and a small team went to Peru, where, with the help of