The story of Easter Island–site of those giant moai, or stone heads–is currently a favorite moral fable among the doomsday set. The idea is that the Easter Islanders destroyed their civilization by having too many babies and not caring enough about the environment–just like us, nowadays.

Here is how the story usually goes, writes anthropologist Terry L. Hunt in American Scientist (thanks, Arts & Letters Daily):

“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.”

Turns out, however, that Diamond wrote his “history” of Easter Island without benefit of doing any archaeology there. And when Hunt and a team of archaeologists started digging there in 2004, they found evidence of a completely different timeline. The signs of human settlement they uncovered showed that the island was completely uninhabited until around 1200, and that the population of Easter Island never exceeded about 3,000, not the 15,000 of Diamond’s estimate. The culprits in the deforestation of the island probably weren’t human beings but a species of Polynesian rat that actually preceded the human settlers by some 300 years. Polynesian rats just love the seeds of the Jubaea palm trees that once covered the island, and they breed so fast that without predators (and there were none on Easter Island), they can double their population in six or seven weeks.

Hunt concludes:

“I believe that the world faces today an unprecedented global environmental crisis, and I see the usefulness of historical examples of the pitfalls of environmental destruction. So it was with some unease that I concluded that Rapa Nui does not provide such a model. But as a scientist I cannot ignore the problems with the accepted narrative of the island’s prehistory. Mistakes or exaggerations in arguments for protecting the environment only lead to oversimplified answers and hurt the cause of environmentalism. We will end up wondering why our simple answers were not enough to make a difference in confronting today’s problems.”