In environmentalist legends, Easter Island was The Ecocide: they built nearly 1,000 giant stone statues but stupidly chopped down all its trees, and died in horrible wars. It was the sorry tale of ecological collapse and deforestation that we could tell small children at bedtime. After the last trees were sliced and diced, a catastrophe of horrors surely followed as the population of 15,000 people ran out of food and no one could make a boat to escape. Obsidian flakes across the island were interpreted as weapons of war and one anthropologist claimed there was a huge civil war that ended in the battle of 1680. Environmental hell on Earth was here…

But new research on the genomes of some islanders suggests that the population was probably small all along. When the Europeans arrived there were only about 3,000 people, and a genetic analysis suggests there are no signs of a recent collapse in the population. Another study of the fields suggests they made some very sophisticated gardens, improving the soil with rocks, can you believe, but they only ever had fields big enough to sustain about 4,000 people, which fits with the gene analysis. And the obsidian fragments were probably domestic tools.

Adding to this tale of remarkable survival,  apparently the inhabitants somehow managed to get to South America and collect some native Indian genes which they brought back. These survived on for another 15 to 20 generations.

So it may be that an isolated island of only 3,000 people was capable of feeding itself sustainably, somehow making huge statues, and also sailing 3,700 kilometres to South America and then finding their way back again. We can imagine a wayward sailor somehow finding South America, but not perhaps on return, an island barely 24 kilometers wide in the vast Pacific. (And maybe, wonders Jo, whether some South Americans just managed a one way trip? How would we know? — On that score, the authors of the Nature paper say they can't tell genetically, but there is archaeological evidence and oral history of trans-Pacific contact from Polynesia right across to South America and back).