Thor Heyerdahl (hā´ərdäl´, hī´–), 1914–2002, Norwegian explorer and anthropologist, b. Larvik. He carried out research in the Marquesas Islands in 1937–38 and studied the indigenous peoples of British Columbia in 1939–40. To support his thesis that the first settlers of Polynesia were of South American origin, in 1947 he and five companions made the crossing from Peru to the Tuamotu Archipelago on a primitive log raft. This voyage is described in the international best seller Kon Tiki (tr. 1950). In 1970, Heyerdahl sailed, in a papyrus boat, from Morocco to Barbados, in an attempt to prove that ancient Mediterranean civilizations could have sailed in reed boats to America. This adventure is described in The Ra Expeditions (tr. 1971). In 1977, he sailed from the Persian Gulf to the Red Sea, following a route he believed was once used by the Sumerians; this trip is detailed in The Tigris Expedition (1979). Heyerdahl was an exponent of the diffusionist school of cultural anthropology, now largely discounted, and today most academics regard his theories as speculative and unproven. His other writings include American Indians in the Pacific (1952), Aku-Aku (tr. 1958), Sea Routes to Polynesia (1968), and Easter Island: The Mystery Solved (1989).
See biography by A. Jacoby (1967).