Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

NOVA Online (click here for NOVA home)
Secrets of Easter Island
menu (see bottom of page for text links)


Your Theories

Below are some of the theories sent in to this Web site about ways to move and erect the moai.


Theory:
I am a fifth-grade student and have been researching Easter Island for my school project. I have read your plans to experiment with the best ways to move the moai. Your daily dispatches are interesting and keep me in touch with your latest activities. I'll be checking your site each day and waiting to see what method for transporting the moai seems to be the best.

I think that they used seaweed as a lubricant to help the moai slide. I do not think they would use anything edible because they were growing short of food.

Elizabeth Nyberg
Old Lyme, CT
Response from Jo Anne Van Tilburg:
Dear Elizabeth,
I agree completely with you! Food was much too important on Rapa Nui to use in such a way! We think one option would be the stumps of banana trees as lubrication - a renewable resource because banana trees must be cut to grow fresh each season.

Theory:
The rolling terrain could work as bridge piers, with logs as rails to slide the statues from the quarry to the placement. Or, the rocks were carved in place, only the rocks transported to the final site. Or, the rocks were in place to start with—they could have been excavated? Does the island have enough wood for any of the methods?

Charles Wolff
Great Falls, Montana
Response:
The stone source for the moai came from the quarries and was not present at the ahu sites. Today there is no available palm wood, specifically Jubea chilensis, which was used by the ancient Easter Islanders on the island. We will be using eucalyptus wood, which was introduced later to the island, but should be strong enough for our experiments.

Theory:
Team: Attach blocks to ends of statues, i.e. head and feet. These blocks would have rounded outsides, where they touch the ground, thus turning the statues into cylinders of a sort, and roll them along roads or wooden rails to the site. Near the site build a ramp of sand and roll statue up it, then dig out in order to place, like Egyptians did with obelisks.

(name withheld by request)
Response from Ted Ralston:
The technical capabilities of the ancient Polynesians were quite incredible and certainly encompassed the use of rollers, which are cylinders. However, no one has yet evaluated the encasing concept from the point of view of materials or technique. There is no evidence of any type of encasing material in the record of the land, however.

Theory:
Would it not be possible to strap ropes from top to bottom to prevent cracking of the statue, then use ropes wrapped around trees and logs as pulleys further using logs as rollers. Then at the site using pulley methods to erect the statue. Finally cutting all the ropes and the statue is erected.

George Durden
Houston, TX
Theory:
I would like to know if it is possible the moai statues could have been loaded on to some sort of boat and then sailed or rowed to the other side of the island? Would there be resources on the island for them to build a boat & are the waters calm enough to carry a statue that big safely around the island?

(name withheld by request)
Response from Jo Anne Van Tilburg:
The waters are often very rough. Coastal loading areas in the vicinity of the statue quarry are not known. However, "canoe ramps" exist in some areas, that may have been used for loading rafts. No clear evidence is available, but the concept is feasible.

Theory:
One method which has not been fully explored is the possibility that the moai were transported to their respective ahu (platforms) via rafts. Since Rano Raraku (the quarry), is relatively near the water, and since the vast majority of ahu are situated on the coastline - it would not be unreasonable to posit the use of rafts to transport the moai around the perimeter of the island.

This seems to me at least as feasible as the prevailing theories of dragging the statues over remarkably rocky and hilly terrain.

David Brookman
Philadelphia, PA
Response from Jo Anne Van Tilburg:
The use of rafts as you describe is not an unreasonable hypothesis; although there is no archaeological evidence of a coastal loading site, canoe ramps exist and could have been used to load statues on ramps. However, overland transport is clear and unquestionable for 97 statues. Thanks for the interest.

Theory:
The various theories of moving the statues by pivoting, tilting, rocking, etcetera seem to consider the terrain as it exists today. It seems that the first requirement to move an object from point A to point B is that there must exist a relatively smooth or navigable route between the two points. This may have been a natural or artificial path of earth and/or sand or other material since eroded away. Once you have established the relatively smooth path the task of movement without damage is much easier. Then methods of mechanical advantage such as levers, inclined planes, pulleys, etc. of various arrangements could do the job. It is interesting to think of the possibilities if they had ice available, or the means of making ice. At any rate I'm suggesting hat the neoliths had to be transported over a relatively smooth path.

Robert Homan
Las Vegas, NV
Response from Jo Anne Van Tilburg:
In fact, the known transport roads are relatively accommodating but only very perfunctory and often smooth. The terrain is quite hilly. No ice is available, then or now. Thanks for the interest.

Theory:
One theory that probably has not been considered is the use of water on land to move the megaliths. I don't mean floating them on a barge down a river, but actually constructing a large portable trough or tank that is filled with water. The megalith is tied to a raft-like structure and the tank is built around the megalith. The tank is filled with water and the megalith is slid or floated forward in the tank. The tank is then deconstructed and shifted forward to allow for the next shift of the megalith. Have you seen how a canal or a ditch is reinforced on the sides when under construction? As the digging progresses, the sides are shifted forward and relocated. Water is obviously a plentiful resource for the island, and the fact that many of these giant stones were moved makes it seem slightly plausible that water could be used on land as part of the plan.

Corrine Terebas
Buffalo, New York
Response from Ted Ralston:
No theory can ever be discounted - some have more support than others do. The present evidence does indicate that a relatively fixed amount of material (rocks) was used in the "work train" that accompanied a moai in motion. Whatever ramps, platforms, or fillers were required were constructed with this loose material, then deconstructed as that step was accomplished - very similar to the modern use of scaffolding, wall forms, blocking, etc. However, the concept of water tanks has not been considered.

Theory:
As a lay person, I'd say they used log-rollers to transport the statue. To erect the statue I'd guess that they used a wooden backdrop and log-rollers and used ropes to pull it up the wooden backdrop with the help of the same log-rollers. Sorta like the Egyptians used to erect obelisks.

Charles Ertel
Schenectady NY
Response from Jo Anne Van Tilburg:
Log rollers are reasonable to assume and we have tested palmwood rollers. They function perfectly when fresh.

Theory:
Wouldn't be possible with their mortar technology to mix and form these stones in place, and shape these forms in the exact spots they now rest?

(name withheld by request)
Response from Jo Anne Van Tilburg:
The carving process, from beginning to final stages, is clearly evident in the quarry, where all but about 30 statues were carved. These 30 came from other, smaller quarries and were transported, finished, to their final sites. Thanks for your interest.

Theory:
Dear Liesl Clark: It is always fascinating to see what sorts of information gets out there! The statue we moved upright here on campus was just short of nine tons and four meters high and represented a slender style of statue. We experimented with about four different methods of moving it, one of which was the tilting method, same as Pavel Pavel, but he used a group of men in closer to the statue with a wooden bar. Ours were much farther away.

The reason this is not the method they used is because the number of folks it takes to tilt it carefully are not very many, but they make a heck of a scuffle with their feet, and thus any amount of work would have produced three roads - the prepared one for the moai transport itself, and two other tracks or trails parallel to it made from the constant scuffling of feet. Using that method we only moved it a few feet before a soft section of our "road" caused it to dig its own hole! We dumped it over a total of four times during our experiments, three times forward, and one backward, and that's the one that keeps getting repeated over the TV, with the implication that method was a failure. It was not. That was the successful method, and the statue, unlike Ms. Van Tilburg's comment, is amazingly stable and no where near as dangerous as it appears. It is tied down to the "pods" as I called them. It fell over backward because our rollers jammed forward of the center of gravity. Subsequent rolling did not

If you would like me to compress a couple of photos and send them your way, I would be happy to do that. They range in size from about 70k to 110k. We are incidentally experimenting with another statue at the moment, so this is a nice coincidence! Please feel free to say hi to Jo Anne, Claudio, Edmundo, Vince and others if you are in contact with them. I wish them all the best of luck in their experiments. Incidentally, I first worked on this in 1982, and then with the big statue in 1987 after earlier failed attempts in 1984. Pavel Pavel did his statue moving in 1986, but had thought about it, he told me, in 1982. Regards,

Charles M. Love
Rock Springs, WY
Response from Jo Anne Van Tilburg and Ted Ralston:
Charlie, you may be interested to learn that rollers are of little use...rolling, sliding, or both occur depending on many factors, including interface friction condition, the ground slope, and surface smoothness condition, material variables. In our experiments, large-diameter palm rollers on smooth surfaces, rollers predominate. On rough surfaces, small-diameter rollers, lubricated sliding predominated. In any case, the lower effort condition, be it rolling, sliding, or a combination, will occur first. In all of our experiments, roller management is extremely difficult. Sliding works like a charm!

Theory:
Is it reasonable to presume that the statues were built on their site rather than having to have been moved to it? Elsewhere on this Web site it is stated that they are constructed of volcanic ash. Perhaps this ash was mined and transported to the site as a powder. It may have been used to construct the statues using methods such as building a sand castle or a snowman. The ash, of course, would have been much more transportable than the fully assembled statue. It is also interesting to note the masonry skills of the Polynesian ancestors which is described also on these pages.

(name withheld by request)
Response:
The tuff, or hardened volcanic ash (rock) that the moai are made of came only from quarries around the island; the rock was not present at the ahu sites.

Theory:
I seem to remember a theory I once heard about how the moai were actually a type of concrete, and that there was a residual chemical mixture on the stone. Is it possible that the statues were poured into molds and then finished?

Perhaps some method of dissolving the stone after it was quarried? Has there been any crystalline structure analysis of the stones to see if this has any merit?

Ryan Remencus
St. Marys, Georgia
Response from Jo Anne Van Tilburg:
Ryan, the moai are carved of compressed volcanic ash from quarries on the island at a place called Rano Raraku. J. Van Tilburg.

Theory:
Perhaps the stones were rounded at the quarry, rolled to their final destination, then chiseled down to the end products.

Randy Young
Denver, CO
Response from Jo Anne Van Tilburg:
Hello Randy, Good question. The quarry, which has been fully mapped, contains 397 statues. All were finished before being transported to their ceremonial sites.
Theory:
Could the statues have been created "on site" out of chunks of lava left from ancient eruptions of volcanoes rather than moved after carving?

(name withheld by request)
Response from Jo Anne Van Tilburg:
The archaeological record is very clear: the statues were all finished prior to moving them to their ahu sites. The pukao were shaped on site and the surface of the statues smoothed before being lifted into place.

Theory:
I'm not particularly knowledgeable about the Easter Island statues, but could the stones that were made into the statues be moved to their destination and then chiseled or the like into each statue. Or the bottom could be chiseled into an arch shape for easier dragging by rope, maybe a lubricant could be spread along the bottom by setting some around it and moving the rock around the immediate area. Not that many people would be necessary, I believe. As for the erection of each statue a collection of smaller but fairly large stones or logs or log-like pieces of wood could be used for leverage and the statue could be lifted because of the heavier base.

Kenny Linsky
Brooklyn, NY
Response from Jo Anne Van Tilburg:
The archaeological evidence is clear, that the statues were all finished prior to moving them out of the quarry. We agree that levers are essential for moving and lifting.

Theory:
I found the response from Jo Anne Van Tilburg, "The archaeological record is very clear: the statues were all finished prior to moving them to their ahu sites," very interesting. Was it not harder to move them carved? Could we please have more information on the record that the statues were all finished prior to moving them. Do you know why they had to be carved first?

(name withheld by request)
Response from Jo Anne Van Tilburg:
Karen, thanks for your message. There are 397 statues still in the quarry, in various stages of carving. All of the statues "in transport" to the ceremonial sites where they were erected, in contrast, are fully carved, down to the very smallest detail. It may have been easier to move them uncarved, but our experiment showed very nicely that fully-carved statues can be moved with no damage to them at all. Our moai got safely to his ahu without breaking, thanks in part to the design of the transport frame on which he was lying. I don't know why they were carved before moving, but I imagine there were many reasons. On Rapa Nui, there are no simple answers to all questions, but we try to look within the island's culture for clues. Thanks.


Past Attempts | Dispatches | The Plan | Team Profiles
Move the Moai Game (get shockwave plug-in) | Your Theories




Move a Megalith | Dispatches | Explore the Island | Lost Civilization
Resources | E-mail | Table of Contents | Easter Island Home

Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule
About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print
PBS Online | NOVA Online | WGBH

© | Updated November 2000

Support provided by

For new content
visit the redesigned
NOVA site