Native Americans and Polynesians were in contact across the Pacific Ocean centuries before Europeans entered Polynesian waters, according to a new study published todaythe journal Nature. Moreover, this initial interaction likely occurred before people settled on Rapa Nui (also known as Easter Island)—the Polynesian island closest to the South American coast that was once thought to be a likely point of contact between the two groups.
Pre-Columbian mingling of Polynesians and Native Americans has long been a subject of debate, one made famous in pop culture by Norwegian adventurer Thor Heyerdahl. In 1947, Heyerdahl embarked on his Kon-Tiki expedition, drifting from Peru to Polynesia on a handmade raft in an attempt to prove that people from the Americas could have populated Pacific islands. Heyerdahl’s controversial theories on the origin of ancient Pacific seafarerscast a taboo over the subject, and many archaeologists have dismissed his ideas.
But other pieces of evidence have suggested there was pre-Columbian contact between people in Polynesia and South America. Previous genetic studies of sweet potatoes suggest the plant was domesticated in Peru and then spread across Polynesia around 1,000 years ago. And the Polynesian name for the root vegetable—"kuumala"—resembles its names in the Andean Quechua language: "kumara" and "cumal."
In recent years, researchers who study human DNA waded into the debate, looking at the genomes of people on Rapa Nui, famous for its towering stone moai statues. A 2014 study of the DNA of 27 people from Rapa Nui found that about 8 percent of their genetic makeup came from Native American ancestors. Those earlier findings suggested that the two groups mixed as early as A.D. 1340, centuries before Europeans first made contact with the Rapa Nui residents in 1722 and, later, violently raided their island for slaves.
For the new study, an international multidisciplinary team looked at the genomes of more than 800 individuals from 17 different Polynesian islands, including Rapa Nui, as well as 15 different coastal Indigenous groups in South America. "Previous studies have been only focusing on the possibility of [Rapa Nui] being the point of contact," says senior author Andrés Moreno-Estrada, a geneticist at Mexico’s National Laboratory of Genomics for Biodiversity. "We opened the question to explore other options in the Pacific."
The researchers found that contact between Polynesian individuals and a Native American group related to present-day Indigenous people in Colombia occurred as early as A.D. 1150—two centuries earlier than indicated by the 2014 DNA study. The place where the researchers could detect the earliest sign of contact was in Fatu Hiva, an island in the South Marquesas. Fatu Hiva is much farther from South America than Rapa Nui, but it could be more easily reached than Rapa Nui due to favorable trade winds and currents, notes archaeologist Paul Wallin of Uppsala University in an editorial accompanying the study in Nature.
Wallin, who also worked at the Kon-Tiki Museum in Oslo, notes that the new results suggest that South Americans reached eastern Polynesia even before Polynesians from points west arrived, which would prove Heyerdahl “partly right.”
But Carl Lipo, a Binghamton University archaeologist who has studied Rapa Nui but wasn’t involved in the new study, says he's not convinced the evidence shows that Heyerdahl was right. The Nature report still leaves open the question of how exactly this contact between Polynesians and Native Americans occurred.
Polynesians may have reached the shores of South America, then colonized other Pacific islands, taking sweet potatoes and Indigenous companions with them. Or their descendants may have returned to Polynesia carrying Indigenous South American genetic heritage. According to Lipo, most archaeological evidence supports one of these scenarios rather than Native Americans reaching Polynesia first.
“Polynesians are long-distance voyagers,” Lipo says. “They moved across incredibly vast areas consistently and found all kinds of margins. We often think of these traditional seafaring groups as moving step-like to close islands and then further and further islands over time, but in fact, what we actually see archaeologically is that people move the farthest distance first. They explored their space and actually ended up in some of the most remote islands early on, and then filled in, colonizing the areas in between."