Easter Islanders Used Rope and Ramps to Put Giant Hats on Statues

Posted on June 4, 2018

Some of the Easter Island statues have enormous red stone hats known as pukao. The Pukao are cylinders made of red scoria. They can weigh up to 12 metric tons. Researchers from Binghamton University in New York say the ancient people of Easter Island used a parbuckling technique involving ramps and rope to get the hats on top of the statues.

Carl Lipo, a professor of anthropology at Binghamton University, says, "Of the many questions that surround the island's past, two tend to stand out: How did people of the past move such massive statues (moai) and how did they place such massive stone hats (pukao) on top of their heads?"

Lupo adds, "We've learned they moved the statues in a walking fashion using simple, physics-based processes, in a way that was elegant and remarkably effective. Our latest study now tackles the issue of the hats (pukao). These multi-ton stone objects were carved at a separate quarry, transported across the island and somehow raised to the top of the heads of the statues."

A recent Newsweek report said the biggest pukao has a diameter of nearly seven feet and weighs over 25,000 pounds. The researchers determined that the ancient Rapa Nui people would most likely have rolled the hats up large ramps using the parbuckling technique. The researchers took photos of different pukao and used them to generate three-dimensional models to determine how they were most likely moved.

Lip says, "In parbuckling, a line would have been wrapped around the pukao cylinder, and then people would have pulled the rope from the top of the platform. This approach minimizes the effort needed to roll the statue up the ramp. Like the way in which the statues were transported, parbuckling was a simple and elegant solution that required minimum resources and effort."

A research paper on the study was published here in the Journal of Archaeological Science.

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