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
Thor Heyerdahl after him, as are HNoMS "Thor Heyerdahl", a Norwegian Nansen class frigate, along with "MS Thor Heyerdahl" (now renamed "MS Vana Tallinn") and "Thor Heyerdahl", a German three-masted sail training vessel originally owned by a participant of the Tigris expedition. Thor Heyerdahl Upper Secondary School in Larvik, the town of his birth, is also named after him. Heyerdahl's numerous awards and honours include the following: Thor Heyerdahl Thor Heyerdahl (; October 6, 1914 – April 18, 2002) was a Norwegian adventurer and ethnographer with a background in zoology, botany, and geography. He became notable for his "Kon-Tiki" expedition in 1947,