Polynesian rats and drought, not statue carving, drove Easter Island deforestation. Polynesian rats arrived with the original settlers and bred rapidly with no natural predators A 2025 study estimated the rat population could have reached 11 million within 50 years Studies of ancient palm nuts found up to 95% had been gnawed through by rats
Two major culprits likely drove Rapa Nui's deforestation: rats and drought. A 2025 study estimated Polynesian rats could have hit 11 million within 50 years of settlement, and ancient palm nut analysis shows up to 95% gnawed through. Rat bone deposits drop ~63% over time, reflecting declining populations. Meanwhile, 2025 sediment cores from crater lakes reveal a severe drought beginning around 1550, cutting rainfall by 600–800 mm annually for about a century.
Key Facts
- Polynesian rats arrived with the original settlers and bred rapidly with no natural predators
- A 2025 study estimated the rat population could have reached 11 million within 50 years
- Studies of ancient palm nuts found up to 95% had been gnawed through by rats
- By around 1650, nearly all of the estimated 15 to 20 million palm trees were gone
- Rat bone deposits in the archaeological record decline by about 63%, suggesting fewer rats were eaten over time
- In 2025, scientists pulled sediment cores from crater lakes showing a severe drought beginning around 1550 and lasting about 100 years
- The drought reduced rainfall by 600 to 800 mm per year
Related site: Easter Island — view location, images, and history on the Ancient Nerds map.
Source: Something Was Very Wrong With Easter Island by Michael Button