The Real Culprit Behind Easter Island’s Lost Forest Isn’t Humans — It’s Millions of Hungry Rats
For decades, the story of Easter Island has been used as a cautionary ecological tale: people cut down their own trees, chaos ensued, and the society collapsed. The long-standing myth paints the Rapa Nui people as relentless tree-cutters who destroyed the forest in order to make a path for their moai statues.
But new research, published in the Journal of Archaeological Sciences, suggests the truth behind the island’s ecological past has an unexpected twist that involves rats. Lots and lots of rats.
“The human impact on these environments is very complex,” said Carl Lipo, from Binghamton University, in a press release. “Sometimes there are unintended consequences, like the rats. In this case, the modification of the environment wasn’t a human disaster.”
Read More: Ancient DNA Can Act Like a Time Machine to Uncover Lost Pacific Cultures
How Millions of Rats Devoured Easter Island Forest
So, how does a palm forest vanish on a remote volcanic island?
Unlike the Norway rats that arrived on the island centuries later, the Polynesian species lived in the canopy cover of trees and had a special fondness for palm nuts. Lipo describes that “palm nuts are rat candy” and that the “rats went bananas” upon seeing the buffet presented to them.
On Rapa Nui, the rats found a paradise with no predators, abundant food, and an agreeable climate. Capable of multiple litters per year, their number skyrocketed into the millions within a few years.
The native palms stood little chance against the tidal wave of rats. With nearly every nut consumed before it could sprout, a new generation of trees simply never grew. Meanwhile, the human population cleared land for sweet potato fields, a vital food source for the new inhabitants. Agriculture and the rats’ voracious hunger sealed the Rapa Nui forest’s fate.
Yet even with such sweeping ecological change, this wasn’t the doomsday scenario the old myth suggested.
As explained by Lipo, “It’s a sad loss of a palm forest, but it wasn’t a disaster for the people. It wasn’t a necessary part of their survival.”
How Did Rats Get to Easter Island?
When Polynesian voyagers arrived on Rapa Nui around 1200 C.E., they brought the usual subsistence package, including sweet potatoes, dogs, chickens, and, tagging along in the boats, Polynesian rats.
Although the reasons for bringing the rats along remain a mystery, ethnographic evidence suggests these animals were brought as a backup food source. Rat bones have also been found in ancient midden deposits across the Pacific Islands, suggesting the rats were commonly eaten.
Rewriting the Story of Easter Island
It is believed that some palms were likely still present after European contact. However, 19th-century sheep ranching brought to the island by the Europeans likely delivered the final blow to the tree population.
Over time, the Polynesian rats met a similar fate as the palm forest. The rat population was eventually wiped out by both the newly introduced Norway rat and by predators like hawks.
This new research on Rapa Nui’s history reveals a society that adapted to dramatic ecological change and not one that caused its own downfall.
“We have to be more nuanced in our understanding of environmental change,” noted Lipo. “We are part of the natural world; we reshape it often for our benefit, but that doesn’t necessarily mean that we create an unsustainable world for ourselves.”
Read More: Unraveling the Story Behind Easter Island’s Resilient Statues
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