Massive stone statues of humanlike figures on Easter Island in the South Pacific stand mute sentry over the remains of a now-defunct society thought by many researchers to have originated as early as A.D. 400.
However, new radiocarbon dates from Easter Island tell a different story. The first Polynesians arrived there around A.D. 1200, rapidly launching construction projects and carving imposing statues that they lugged all over the island, two anthropologists report in the March 17 Science. Cultural growth fostered tree loss and soil erosion that continued after European contact 500 years later, they say.
Terry L. Hunt of the University of Hawaii–Manoa in Honolulu and Carl P. Lipo of California State University in Long Beach obtained radiocarbon dates for burned wood from various soil layers at an Easter Island site containing animal bones and other remains left by former inhabitants. Hunt and Lipo excavated the deposit, which lies in the island’s only sand dune, during 2004 and 2005.
Hunt and Lipo disagree with the notion, advanced by Jared Diamond of the University of California, Los Angeles in his book Collapse (2005, Viking Penguin, New York), that population growth and environmental destruction at first fueled Easter Islanders’ cultural achievements but caused social chaos by the time of European contact.
“We see the grand scale of cultural investment on [Easter Island] as the cause of their salvation, not of their demise,” Hunt says. The island culture’s downfall came from European-based disease and slave trading, in his view.
A late arrival for Easter Islanders fits with an earlier theory that Polynesians spread quickly from one Pacific island to the next because of rapid population growth and intensive exploitation of island resources, Hunt says.
In the isolated, harsh locale, Easter Islanders focused on activities such as building monuments and carving statues rather than on raising large, unsupportable families, Hunt and Lipo propose. In habitats with unpredictable resources, many animal species show a preference for non-reproductive activities, they note.
Hunt and Lipo’s revised dating of Easter Island’s settlement makes “much better sense of other archaeological evidence,” remarks archaeologist Paul Rainbird of the University of Wales, Lampeter. For example, colonization at A.D. 1200 allows for the sweet potato to have been cultivated in central and eastern Polynesia for at least 200 years before its transport to Easter Island as the main plant crop.
However, Hunt and Lipo’s evidence doesn’t represent an “ironclad” case for a late settlement, contends anthropologist Patrick V. Kirch of the University of California, Berkeley. He notes that previous radiocarbon analyses of the same site, directed by David W. Steadman of the University of Florida in Gainesville, suggested that people reached Easter Island perhaps by A.D. 900.
Recent work on the Mangareva Islands, the probable source of the first Easter Island colonists, suggests that the islands were settled between A.D. 900 and A.D. 1000, Kirch adds. Easter Island could have been colonized around the same time, in his view.