University of Hawaii professor Terry Hunt was conducting archaeological digs on the South Pacific island of Rapa Nui when he came upon evidence that ran against the prevailing belief that the natives were entirely to blame for the rapid deforestation of the island.
"Rats played a significant role in the deforestation," said Hunt.
Hunt said the digs found palm tree seeds hundreds of years old that had been eaten by an exploding rat population.
The findings are published by Hunt and co-author Carl Lipo this year in the book "The Statues That Walked: Unraveling the Mystery of Easter Island," published by Free Press.
The island, which is claimed by Chile, is about 63 square miles in size and is the farthest east of any occupied Polynesian island.
Another popular belief is that the statues were moved into place by pulling them along on rolling logs.
Hunt said the stone statues, or "moai," were built with a rocker-type mechanism at the base that enabled a handful of men to push and "walk" a statue, in the upright position, over many miles with surprising ease.
Hunt said new archaeological evidence suggests early Polynesians who settled there from the Tahiti region did contribute to deforestation through agriculture.
"It’s a combination of factors," he said.
Hunt said the Rapa Nui natives improved the productivity of the land, which was nutrient-poor, by using stones as a kind of mulch to create planting areas, similar to Polynesians in dry-land areas in Kona and on Maui.
"The ancient Polynesians of Rapa Nui were making it the most sustainable island possible," he said.
Hunt said the only record of early population is by the earliest European explorer, Jacob Roggeveen in 1722, who estimated the number of islanders at about 3,000.
The island now has about 4,000 residents, including more than 3,000 Rapa Nui natives, he said.
Hunt said contrary to popular belief, there’s evidence showing the island prior to European arrival had no central leadership, but had a collection of tribes that came together occasionally.
"People lived in dispersed settlements," he said. "There wasn’t really anybody at the top."
Recent studies say the people who eventually became known as Polynesians migrated east to Samoa and Tonga in 800 B.C., then began moving eastward again in A.D. 1100, settling Tahiti, and moving into the remaining islands of the eastern Pacific between A.D. 1200 and 1300, including the Marquesas, New Zealand, Rapa Nui and the Hawaiian Islands.
Hunt said according to newly reported radio carbon dating, Polynesians from the Society Islands settled on Rapa Nui and the Hawaiian Islands during the same period, explaining the reason for their similar oral history traditions and languages.
"The legends and cosmology in East Polynesia are very similar because of their shared origins," he said.
Hunt said the double-hulled sailing canoe capable of carrying large groups of people, animals and plants played a significant role in the migration to the islands.
"That invention would have made these long-distance migrations possible. … It certainly facilitated successful discovery and colonization of hundreds of remote islands," Hunt said.