The rats of Easter Island

Were rats somehow involved in the demise of Easter Island? According to USA Today, that's the theory of researchers from the University of Hawaii at Manoa.

Well, rats and Europeans.

The accepted wisdom has been this: The natives deforested the land in order to transport the 10-ton stone statues for which the island is renowned. This deforestation brought about erosion and the destruction of farmland. Then the natives destroyed themselves in a cannibalistic civil war in the 17th century.

But, according to the new theory, rats -- "the rodent population spiked at 20 million from 1200 to 1300 and then dropped off to a mere 1 million after the trees were gone" -- likely "deforested the 66-square-mile island's 16 million palm trees" well before humans arrived on the island in significant numbers. So "the disappearance of Easter Islanders probably was caused by visiting Dutch traders in the 1700s, who brought diseases and, later, slave raiding".

The fate of the Easter Islanders has been linked directly to environmental irresponsibility, a cautionary example of what can happen when humans interfere with the environment. If this new theory is true, however, there may be a new lesson: This is what can happen when "invasive species" enter a new environment and interfere with the native population.

It's a fascinating discovery.