Rollers, wooden carts, and even alien life are just a few of the theories of how people moved the iconic moai statues of Easter Island (also called Rapa Nui). These roughly 130,000-pound, 32-foot-high statues somehow made it about 11 miles from the volcanic quarries where they were made to their final positions, over hilly terrain–all without modern technology.
Now, using 3D modeling and field experiments from archeologists and anthropologists, we might finally have an answer. Rope and “walking” along specially designed roads moved the giant statues, according to a study recently published in the Journal of Archaeological Science.
“It shows that the Rapa Nui people were incredibly smart. They figured this out,” study co-author and Binghamton University anthropologist Carl Lipo said in a statement. “They’re doing it the way that’s consistent with the resources they have. So it really gives honor to those people, saying, look at what they were able to achieve, and we have a lot to learn from them in these principles.”
What are the moai statues?
Rap Nui’s moai statues are massive megaliths that were built by the Rapa Nui people in roughly 1400–1650 CE. Most people know them as the Easter Island heads, but these heads do have full bodies.
There are about 1,000 of these enormous statues. About 95 percent of them were carved out of tuff ejected from volcano Rano Raraku. Tuff is a compressed volcanic ash and is easy to carve with the stone tools available at the time called toki.
The moai statues were built in honor of chieftains and other important people who had died. The statues were placed on rectangular stone platforms called ahu, which serve as tombs. Initially, the moais were made with different characteristics to represent the appearance of the deceased.
‘The physics makes sense’
In this new study of roughly 1,000 moai statues, a team put this to the test. The same team previously showed that an upright, rocking motion, let the large statues “walk” from their volcanic quarry over to the ceremonial platforms.
“Once you get it moving, it isn’t hard at all – people are pulling with one arm. It conserves energy, and it moves really quickly,” said Lipo. “The hard part is getting it rocking in the first place. The question is, if it’s really large, what would it take? Are the things that we saw experimentally consistent with what we would expect from a physics perspective?”
To see how a larger statue might move, the team created high-resolution 3D models of the moai. With these models, they identified distinctive design features, including wide D-shaped bases and a forward lean. These bases would make them more likely to be moved in a rocking, zig-zagging motion.
They then built a 4.35-ton replica moai with the distinct forward-lean design to test out this theory. They could move the moai about 328 feet in 40 minutes, with a team of only 18 people.
“The physics makes sense,” said Lipo. “What we saw experimentally actually works. And as it gets bigger, it still works. All the attributes that we see about moving gigantic ones only get more and more consistent the bigger and bigger they get, because it becomes the only way you could move it.”
Passing the road test
The roads of Rapa Nui also lend some support to this new theory. At about 14-feet-wide with a concave cross-section, these roads were ideal for stabilizing the statues as they moved.
“Every time they’re moving a statue, it looks like they’re making a road. The road is part of moving the statue,” said Lipo. “We actually see them overlapping each other, and many parallel versions of them. What they are probably doing is clearing a path, moving it, clearing another, clearing it further, and moving it right in certain sequences. So they’re spending a lot of time on the road part.”
According to the team, there are no other real theories that could explain how the moai were moved. Rapa Nui is notorious for wild theories that have zero evidence, and the team worked to put a real theory to the test.
“People have spun all kinds of tales about stuff that’s plausible or possible in some way, but they never go about evaluating the evidence to show that, in fact, you can learn about the past and explain the record that you see in ways that are fully scientific,” said Lipo. “One of the steps is simply saying, ‘Look, we can build an answer here.’”
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