You could say Rapa Nui is in the middle of nowhere, but it’s even less central than that. Moored in the empty South Pacific, this barren outcrop of land, also known as Easter Island, is some 1,300 miles southeast of its closest inhabited neighbor and about 2,200 miles west of mainland Chile.
For centuries, scholars have been puzzled by the movement of the Rapa Nui moai, monolithic stone figures that represent deified ancestors. Between A.D. 1200 and 1700, the statues were hewed from compacted ash in a quarry inside the crater of the extinct volcano Rano Raraku, and then transported as far as 11 miles across rugged terrain; some reached 33 feet in height and weighed as much as 86 tons.
Roughly 950 moai have been discovered on the island. Most face inland with their backs to the ocean to watch over the villages, but seven on the west-oriented slopes of the Terevaka volcano are positioned to precisely face the sunset during the equinoxes, suggesting that the site once served as an astronomical observatory. About 400 moai are still in the quarry, and 62 lie on the ground between the quarry and ceremonial platforms along the coast. All these numbers are hotly debated, as is the question of whether the 62 moai were abandoned in transit or purposely left at their sites.
In a recent study published in The Journal of Archaeological Science, Carl Lipo of Binghamton University and Terry Hunt of the University of Arizona demonstrated a plausible technique for how the statues were moved. Fourteen years ago, the researchers’ 18-person crew shimmied a 4.35-ton concrete replica over a 328-foot distance in just 40 minutes by using ropes attached to the sculpture’s head, causing it to rock and shift its weight from side to side with each tug, gradually advancing it forward. This experiment called into question existing theories about moai transport and reinforced ones proposed in Dr. Lipo and Dr. Hunt’s 2011 book “The Statues That Walked: Unraveling the Mystery of Easter Island.”
The concept of moving a moai by walking it, inspired by oral tradition, was first successfully re-enacted in 1986 by the Czech archaeologist Pavel Pavel and the Norwegian ethnographer Thor Heyerdahl. Their test runs were met with skepticism, primarily because detractors believed the method could harm the statues’ bases, would not work on uneven ground and involved a 15-ton model that was not representative of all moai sizes. The walking-heads theory also lacked regional precedent. Despite these criticisms, Mr. Heyerdahl’s fame as an explorer, combined with Mr. Pavel’s engineering expertise, led to serious public and academic interest.
Giant Steps
The new paper details how Dr. Lipo, Dr. Hunt and their colleagues created 3-D models to understand how specific shapes and proportions would enable or hinder different transport techniques. This allowed the team to determine the ideal center of mass and stability needed for an upright, zigzag motion.
The study pointed out that road moai — statues discovered along what some researchers believed to be ancient transport paths, typically facedown on downward slopes and on their backs on inclines — shared distinct design features. These included wide, D-shaped bases and forward-leaning postures, which are physically optimized for rocking the giant sculptures, the researchers said. Dr. Lipo and Dr. Hunt proposed that damage such as side fractures could be the result of falls sustained by the sculptures during such walks, and that the guiding, concave design of the roads helped keep the wavering moai on course.
Dr. Lipo said that the constant rocking and shifting of the moai over time wore down and contoured the prepared paths. “Every time the Rapanui moved a statue, it looks like they made a road,” he said. “The road was part of moving the statue.”
In the paper, the researchers present their work as “a vindication of experimental archaeology and a case study of scientific resistance to paradigm change.” But their research has faced pushback. Nicolas Cauwe, curator of prehistoric and oceanic collections at the Royal Museums of Art and History in Brussels and author of “Easter Island: The Great Taboo,” argues that Dr. Lipo and Dr. Hunt may have misinterpreted some of the evidence. Roughly half of the statues discovered along the paths are intact, and even the broken ones have fragments nearby. This suggests that the moai cracked while prone, rather than falling during transport, Dr. Cauwe said.
In his view, the narrow runnels caused by rainwater erosion indicate that the statues stood upright along the trails for an extended period — potentially decades or possibly more than a century. He also noted that the style of the road moai more closely resembled the statues found on the volcano’s slopes than those erected on ceremonial platforms.
“Based upon these characteristics, it appears that the moai lying along the ancient paths have nothing to do with transport,” Dr. Cauwe said.
A Flawed Diamond
The popular perception of Rapa Nui was shaped by Jared Diamond’s 2005 best seller “Collapse: How Societies Choose to Fail or Succeed,” which proposed a narrative of self-inflicted ecological disaster. Dr. Diamond, now an emeritus professor of geography at the University of California, Los Angeles, claimed that an escalating rivalry among the islanders led them to construct increasingly massive moai, requiring extensive logging of the island’s once-abundant palm forests for transport equipment like sledges, rollers and ropes.
In Dr. Diamond’s account, the resulting widespread deforestation caused soil erosion and famine. This environmental and food crisis ultimately led to a complete societal collapse marked by warfare and cannibalism, even before the Dutch arrived in 1722. This theory presents the Rapanui as a cautionary tale of a culture that consumed its own resources to extinction.
After the book’s publication, doubts about Rapa Nui’s ecocide spread among researchers, who voiced their concerns at conferences and in numerous scientific articles. Jan J. Boersema, an environmental scientist at Leiden University in the Netherlands, recalled that the concerns culminated in a consensus. “Scientifically, the collapse theory was dead by 2015,” he said.
In a 2007 paper, Dr. Lipo and Dr. Hunt challenged Dr. Diamond’s version of Easter Island history, instead suggesting that the Rapa Nui society was functional and thriving upon the arrival of the Dutch. They noted a lack of archaeological evidence for widespread warfare, such as fortifications or signs of violence among skeletal remains, common on other Polynesian islands. The obsidian tools found were consistent with agricultural use. “The most deadly objects found on Rapa Nui, and certainly used by Rapanui against Europeans, are large rocks thrown at heads,” Dr. Lipo said.
Researchers, including Dr. Lipo and Dr. Hunt, later used satellite imagery data to map Rapa Nui’s rock gardens, an innovative farming system for sweet potatoes and other crops that allowed the inhabitants to manage a limited environment sustainably. Based on the smaller scale of these gardens compared with earlier assumptions, the researchers estimated the island’s maximum population capacity at a stable 3,000 to 4,000 people. This figure aligns with population sizes recorded by early European visitors, countering theories of a massive ecocide.
Dr. Lipo and Dr. Hunt attributed the subsequent population decline — down to just 111 individuals by 1877 — to external factors introduced by the Europeans. These factors included epidemics of diseases such as tuberculosis, dysentery and leprosy; the effects of the slave trade, and land theft, all of which hint at an otherwise resilient society that was overcome by outside forces.
“Their work is hugely significant,” Ethan E. Cochrane, an anthropologist at the University of Auckland in New Zealand, said of the quarter-century of research by Dr. Lipo, Dr. Hunt and their colleagues. “It has exposed the public parable of Easter Island and turned it on its head to demonstrate the people of Rapa Nui to be resourceful and inventive, making one of the most unlivable places on earth habitable for centuries and creating some of the world’s most recognizable monuments.”
Dr. Boersema was more measured. If the data were correct, they presented strong evidence that the moai were moved upright, he said, although he added that “it does not rule out the use of other methods, such as sledges on rollers, particularly for maneuvering in steep terrain.”
Not Set in Stone
Jo Anne Van Tilburg, an archaeologist at the University of California, Los Angeles, began her fieldwork in Rapa Nui in 1982. She leads the Easter Island Statue Project, which is expected to release a 600-page academic atlas next March. This comprehensive study aims to link soil fertility, agriculture, quarrying and the sacredness of the moai.
Dr. Van Tilburg is a proponent of the horizontal transport theory, which argues that the moai were moved lying down, either on their backs or facedown. She posits that the Rapanui were resourceful engineers who used a single V-shaped wooden frame both as a sledge, moved with log rollers from the Rano Raraku quarry, and as a levering mechanism to raise the statues upright at their final destinations.
In a 1998 experiment, which proved that this method was feasible, Dr. Van Tilburg’s team successfully moved a 10-ton, 14-foot-tall moai — a concrete mix cast in a fiberglass mold — using about 50 people over relatively flat ground and up an incline. A smaller crew then used levers to raise the statue onto a platform replica. The team initially tried eucalyptus rollers, but these jammed; they then modified the technique to lash the rollers to the sledge and slide the entire rig over eucalyptus rails. This technique was grounded in established Polynesian canoe-ladder technology. Regarding the walking theory, Dr. Van Tilburg said, “Just because something could be done, doesn’t mean it was.”
She did not discount a maritime alternative, citing 17 documented canoe ramps that could have been used to load statues onto rafts for coastal transport. Given the pros and cons of all theories, she suggested that the Rapanui were likely to have used whichever method was most practical at the time.
“Trying to encapsulate in one theory the range of human behavior and the complexities of a rich island culture history within a marginal island environment is rarely a good idea,” Dr. Van Tilburg said.
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