NEWSFOCUS Beyond Kon-Tiki: Did Polynesians Sail to South America? After decades of taboo and controversy, Pacifi c Rim archaeologists are fi nding new evidence that Polynesians reached South America before Europeans did, voyaging across the world’s largest ocean around 1200 C.E. on March 12, 2012 IT WAS LATE IN THE DAY IN DECEMBER 2007 drive to settle a long-standing controversy to crumble, giving archaeologists a chance when the curator pulled out a half-dozen among archaeologists and anthropologists. to rethink the way technology and innova- ancient human skulls from dusty drawers Considered the realm of crackpot theorists tions spread in prehistory. in the museum in Concepción, Chile. The until recently, the idea of prehistoric contact skulls, of varying ages, had been found dur- between Polynesians and South Americans Heyerdahl’s ghost www.sciencemag.org ing the past century by locals as well as sci- has gone mainstream. A new generation of The idea that Polynesians and South Ameri- entists on the windswept island of Mocha, researchers is using DNA analysis of varied cans were in touch more than 500 years ago 30 kilometers off the southern Chilean coast. organisms such as humans, chickens, and is as old as archaeology itself. In 1837, a “I nearly dropped to the fl oor,” recalls Lisa sweet potatoes to add compelling data to a French writer noted that plank boats used Matisoo-Smith, a biological anthropologist case previously based on more nebulous lin- by locals on the west coast of Chile were at the University of Otago in New Zealand. guistic and artifact similarities. Given current remarkably similar to those found in Tahiti. She immediately noticed that some crania views of Polynesian expansion (see sidebar, Two years later, a British sea captain pointed had characteristics hinting at a Polynesian p. 1346), many researchers now think it likely out that the Patagonian and Polynesian words Downloaded from origin, such as a pentagonal shape when that Polynesians reached South America for canoes—kialu and kialoa, respectively— viewed from behind. by about 1200 C.E., after the settlement of were nearly the same, notes Kathryn Klar, a Mocha is 3700 Easter Island, and several centuries before linguist at the University of California (UC), Online kilometers east of Eas- Europeans arrived around 1500 C.E. Berkeley. An archaeologist suggested in the sciencemag.org ter Island, the clos- “This is a watershed moment,” archae- 1930s that the sweet potato diffused from Podcast interview est known prehistoric ologist James Bayman of the University of its home in the Andes to the Pacifi c before with author Polynesian settlement. Hawaii, Manoa, told participants at a ses- Columbus. And researchers at a 1968 con- Andrew Lawler. Matisoo-Smith was in sion on the topic at the meeting of the Soci- ference concluded that the pre-Columbian Chile on a hunt for rat ety for American Archaeologists (SAA) in presence in Polynesia of indigenous South bones that might show Polynesian contact St. Louis, Missouri, in April. “New methods American plants like the sweet potato were with South America; she hadn’t imagined no longer give us an excuse to ignore the likely signs of prehistoric contact. stumbling on human remains that might issue.” Some skeptics point out that there is There is no question that the Polynesians bolster that case. She and Chilean colleague still no incontrovertible evidence that Poly- were the great premodern seafarers, spread- José-Miguel Ramírez-Aliaga of the Univer- nesians went to South America and then ing east from Asia and Melanesia in outrig- sidad de Valparaiso hope to win agreement returned to Pacifi c islands, and contact with ger canoes and arriving on the shores of from local peoples and the Chilean govern- North America remains questionable (see Fiji by 1000 B.C.E. (Science, 2 March 2001, ment for an excavation on Mocha to seek sidebar, p. 1347). Bayman admits that the p. 1735). By 1200 C.E., using sails and signs of Polynesian settlement, artifacts, research “is still a work in progress.” But he sophisticated navigation techniques, they and human and animal remains. and many colleagues agree that resistance had peopled most South Pacific islands, Their effort is one part of an ambitious to the idea of prehistoric contact is starting including Hawaii and Easter Island on the PHILIP DE BAY/CORBIS CREDIT: 1344 11 JUNE 2010 VOL 328 SCIENCE www.sciencemag.org Published by AAAS NEWSFOCUS Seaworthy. The reach of Polynesians, shown here in this 18th century engraving, may have extended as far east as South America. eastern edge of the Pacifi c. But did they go all the way to South America? Scientists largely blame Thor Heyerdahl, the famous Norwegian writer and adven- turer, for souring academia on that idea. In 1947, Heyerdahl and a crew of five sailed nearly 7000 kilometers from Peru to French Polynesia on a balsa-wood raft dubbed the Kon-Tiki to prove that ancient Americans could have sailed east to colo- nize the Pacifi c. The trip and resulting book Stone age. Ramírez-Aliaga made him a worldwide celebrity. Heyerdahl (right) notes that Ma¯ori hand thought that the original seafarers came clubs (top row) resemble Mapu- from the Middle East via South America, che versions from Chile. where they bestowed civilization on dark- skinned peoples before setting off across in the uplands of Peru, where it became genetic tools are clinching the argument the world’s largest ocean. an important staple, according to Andrew that sweet potatoes were brought to Pacifi c Such racist assumptions and a lack of sci- Clarke, a molecular biologist at the Uni- islands before the advent of Europeans. “It entifi c rigor horrifi ed many anthropologists versity of Otago. Unlike the coconut or is easy to spot changes in the sweet potato and tarred researchers who wanted to exam- the gourd, which can naturally fl oat from genome over time,” explains Clarke, who ine such prehistoric long-distance connec- island to island, “the sweet potato needs presented some of his data at the SAA meet- on March 12, 2012 tions more thoroughly. “People asked me if I people” to spread, he says. Some scholars ing. That’s because his team of research- wanted to ruin my career and be considered in the past argued that the sweet potato was ers from New Zealand and Japan is using a a fool,” recalls Terry Jones, now a professor exported to Southeast Asia by the Spanish high-resolution molecular marker technique at California Polytechnic State University in and Portuguese in post-Columbian times, to illuminate the large amount of genetic San Luis Obispo. The topic is still contro- then spread east across the Pacific. But variation found in the plant. They examined versial, though no longer taboo. “We have to the tuber, still a mainstay of the Polyne- 300 samples collected from around Ocea- tiptoe back and reexamine just what the con- sian diet, has shown up frequently in much nia, South America, and Southeast Asia and nections are,” says archaeologist Terry Hunt earlier Pacifi c sites. Patrick Kirch of UC found that the varieties common in Polyne- www.sciencemag.org of the University of Hawaii, Manoa. Berkeley, for example, dated a carbonized sia differ from those brought by Europeans The most compelling evidence, schol- sample from the Cook Islands northeast of to Southeast Asia; the Polynesian varieties ars say, centers on the humble sweet potato. New Zealand at about 1000 C.E. are more directly related to the South Amer- That tuber is widely recognized to have been Such ancient samples have been known ican ones, Clarke says, strongly suggesting CREDITS (TOP TO BOTTOM): COURTESY J.-M. RAMÍREZ-ALIAGA (2); ADAPTED FROM GOOGLEMAPS CREDITS (TOP TO BOTTOM):COURTESY domesticated only once, about 6000 B.C.E. for decades but received little attention. Now prehistoric contact. Chicken feed POLYNESIAN DIASPORA Just how a highland Andes crop Downloaded from Hawaii appeared in Polynesia in pre-Columbian times remains controversial. “The sweet potato shows movement from South America to Polynesia, but not how it hap- Quito pened or who was involved,” says Atholl Guayaquil Solomon Anderson, an archaeologist at the Aus- Islands Marquesas Society Islands tralian National University in Canberra. Samoa Islands Lima Given the crop’s highland origin and Fiji Cook Tahiti the prevailing winds, he argues that it is Tonga Islands more likely that Amerindians dispersed the tuber to Pacifi c islands, moving west Easter Island as Heyerdahl had proposed. Santiago But most researchers see few signs Concepción of Amerindian excursions into the New Zealand Pacifi c. Cultural anthropologist Richard Scaglion of the University of Pittsburgh in Pennsylvania instead argues that Poly- nesians may have arrived at the southern coast of South America and sailed north using the prevailing current to the Ecua- www.sciencemag.org SCIENCE VOL 328 11 JUNE 2010 1345 Published by AAAS NEWSFOCUS dorian port of Guayaquil, the only sheltered Polynesians celebrated the port in South America north of the rocky New Year with the rising of southern coast of Chile. The Canara people the Pleiades after the winter once lived from this area of the coast into the solstice and used a magic toki Andes highlands, making the sweet potato to cut trees. Both play a game accessible to coastal visitors. And here the similar to field hockey, pai current veers sharply west. Computer simu- pai in the Austral Islands and lations show that “the most successful return palin in Mapuche. [westward] from the coast would be from Despite the sweet pota- Guayaquil to Polynesia,” Scaglion adds, to’s strong evidence, so far making this area “a possible locus of trans- there is no evidence for other Pacifi c contact.” common Polynesian ani- Climate change may also have played a mals, like the dog and rat, role in prehistoric contact.