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 Museum and the National Library of Norway in Oslo. Heyerdahl was born in Larvik, Norway, the son of master brewer Thor Heyerdahl (1869–1957) and his wife, Alison Lyng (1873–1965). As a young child, Heyerdahl showed a strong interest in zoology, inspired by his mother who had a strong interest in Charles Darwin's theory of evolution. He created a small museum in his childhood home, with a common adder ("Vipera berus") as the main attraction. He studied zoology and geography at the faculty of biological science at the University of Oslo. At the same time, he privately studied Polynesian culture and