Every year, thousands of tourists from around the world take a long flight across the South Pacific to see the famous stone statues of Easter Island. Since 1722, when the first Europeans arrived, these megalithic figures, or moai, have intrigued visitors. Interest in how these artifacts were built and moved led to another puzzling question: What happened to the people who created them?

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In the prevailing account of the island's past, the native inhabitants—who refer to themselves as the Rapanui and to the island as Rapa Nui—once had a large and thriving society, but they doomed themselves by degrading their environment. According to this version of events, a small group of Polynesian settlers arrived around 800 to 900 A.D., and the island's population grew slowly at first. Around 1200 A.D., their growing numbers and an obsession with building moai led to increased pressure on the environment. By the end of the 17th century, the Rapanui had deforested the island, triggering war, famine and cultural collapse.

Jared Diamond, a geographer and physiologist at the University of California, Los Angeles, has used Rapa Nui as a parable of the dangers of environmental destruction. "In just a few centuries," he wrote in a 1995 article for Discover magazine, "the people of Easter Island wiped out their forest, drove their plants and animals to extinction, and saw their complex society spiral into chaos and cannibalism. Are we about to follow their lead?" In his 2005 book Collapse, Diamond described Rapa Nui as "the clearest example of a society that destroyed itself by overexploiting its own resources."

Two key elements of Diamond's account are the large number of Polynesians living on the island and their propensity for felling trees. He reviews estimates of the island's native population and says that he would not be surprised if it exceeded 15,000 at its peak. Once the large stands of palm trees were all cut down, the result was "starvation, a population crash, and a descent into cannibalism." When Europeans arrived in the 18th century, they found only a small remnant of this civilization.

Diamond is certainly not alone in seeing Rapa Nui as an environmental morality tale. In their book Easter Island, Earth Island, authors John R. Flenley of Massey University in New Zealand and Paul G. Bahn worried about what the fate of Rapa Nui means for the rest of human civilization: "Humankind's covetousness is boundless. Its selfishness appears to be genetically inborn…. But in a limited ecosystem, selfishness leads to increasing population imbalance, population crash, and ultimately extinction."

When I first went to Rapa Nui to conduct archaeological research, I expected to help confirm this story. Instead, I found evidence that just didn't fit the underlying timeline. As I looked more closely at data from earlier archaeological excavations and at some similar work on other Pacific islands, I realized that much of what was claimed about Rapa Nui's prehistory was speculation. I am now convinced that self-induced environmental collapse simply does not explain the fall of the Rapanui.

Radiocarbon dates from work I conducted with a colleague and a number of students over the past several years and related paleoenvironmental data point to a different explanation for what happened on this small isle. The story is more complex than usually depicted.

The first colonists may not have arrived until centuries later than has been thought, and they did not travel alone. They brought along chickens and rats, both of which served as sources of food. More important, however, was what the rats ate. These prolific rodents may have been the primary cause of the island's environmental degradation. Using Rapa Nui as an example of "ecocide," as Diamond has called it, makes for a compelling narrative, but the reality of the island's tragic history is no less meaningful.