Don't believe it? The evidence is here.
DNA from chicken bone shows Polynesians 'found' South America
A chicken bone has provided anthropologists with the strongest evidence yet to suggest that Polynesians sailed to South America before the discovery of the New World by Europeans.
Speculation that Polynesians may have settled in South America, however, is not grounded.
Genetic studies of modern South Americans have not uncovered any signs of Polynesian ancestry. But this is not surprising, says Matisoo-Smith. Ancient Polynesians were great explorers, but tended to settle only in uninhabited islands.
This discovery may tie in to the longstanding question of how sweet potato, which originated in South America, found a new home in Polynesia. If Polynesians brought chickens to South America, why wouldn't they bring back the sweet potato — the only Polynesian starch or vegetable that did not originate in Asia. This article was written in 2004.
BBC: The Mystery of the Sweet Potato
The islands of Polynesia have long been a source of mystery and speculation for armchair scientists. The origin of the Easter Island statues, the abandonment of the so-called 'Mystery Islands' and the ultimate origins of the Polynesian people are some of the more well-known. However, perhaps the greatest mystery of them all is that of the sweet potato.