First, they set the date for colonization of the island to 1200 A.D. in a radiocarbon dating paper in the journal Science, more recent by at least a century than past estimates. Next, they proposed, based on DNA evidence and chewed palm remains in the Journal of Archaeological Science, that Polynesian rats brought with those immigrants had been the culprits behind deforestation, eating palm tree nuts.
Without predators to keep rat numbers in check, the rodents ate most of the seeds and the older trees had mainly died out without reproducing by 1772 when Europeans arrived in ships. Those Europeans wiped out the islanders, they suggested, through disease and later enslavement. “It was genocide, not ecocide, that caused the demise of the Rapanui. An ecological catastrophe did occur on Rapa Nui, but it was the result of a number of factors, not just human short-sightedness,” Hunt wrote in The American Scientist magazine.