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New Book Summarizes Decades of Easter Island Research by UW Scientists, Others

January 26, 2017
man examining human bones on the ground
George Gill, scientific leader of the 1981 Easter Island anthropological expedition, examines human bones in the Koe Hoko burial cave in 1981. (National Geographic Society Photo)

Mention the name Easter Island, and images of giant stone statues with oversized heads may come to mind. These monumental figures account for one of the many mysteries surrounding the remote island in the Pacific Ocean and its earliest inhabitants.

A new reference book sheds light on some of the mysteries by providing evidence from human biology that modifies earlier archaeological and cultural anthropological views. “Skeletal Biology of the Ancient Rapanui (Easter Islanders)” is the culmination of nearly 40 years of research by University of Wyoming anthropologists and students, and researchers from other universities and institutions.

George Gill, a professor emeritus of anthropology at UW, and Vincent Stefan, a professor of anthropology at Herbert H. Lehman College in New York and a UW alumnus, are co-editors of the book.

“I think the release of this book is really a major step forward in solving some of the major mysteries of Easter Island,” says Gill, who wrote or co-wrote seven of the book’s 16 chapters.

Those mysteries include: Who were the inhabitants; when and how did they settle the island; what led to the decline of the advanced civilization; and how did they carve and move the statues?

Gill and a team of researchers collected and analyzed data from human skeletons that were excavated on Easter Island primarily during a 1981 anthropological expedition, in which Gill was the scientific leader. The initial sample size of skeletons from that expedition was 426. During subsequent trips to the island, the research team collected data on additional skeletons to add to its database.

Scholars have debated the origins of the first inhabitants for centuries. Did they come from South America, East Polynesia or Central Polynesia?

“The bones have helped tell the story about who they were,” Gill says.

Stefan, one of Gill’s former students from Rock Springs, performed extensive craniometric analyses (skull measurements) of the excavated skeletons on Easter Island. Additionally, he examined Rapanui skulls housed at museums around the world as well as skeletal collections from other Polynesian islands.

Stefan’s research identifies a close relationship between the Rapanui and the populations that occupy Mangareva, the largest island of the Gambier Islands in East Polynesia, and the Tuamotus, a French Polynesian chain of almost 80 islands and atolls.

Although the early Rapanui were primarily Polynesian, a detectable “thread” of Native American ancestry exists, according to Gill’s research, which is backed by DNA evidence.

As a forensic anthropologist, Gill’s specialty is identifying race from the bones. He looked at a few traits on the face that show genetic composition well and differences among populations rather clearly.

“Some of those that were leaning away from the East Polynesian norm were pointing -- every one of them -- toward Native American ancestry,” Gill says. “So, we’ve concluded the argument that’s been going on for decades over whether there was any Native American influence or not. There was, but it was small.”

Answers about when and how the ancient Rapanui settled the island have not been clearly established. The book explores some settlement theories, including Gill’s “sojourn” theory, in which he hypothesizes that the earliest settlement voyage to the island came from East Polynesia, but not directly. East Polynesians, who were on a colonizing voyage, arrived at South America. Years later, the majority of these people set out to return to their homeland, but ended up at Easter Island.

“There’s still room to improve our comprehension of exactly how the island was settled and the timing, too,” Gill says.

Based on new radiocarbon dates from excavations, some researchers conclude that the island was colonized soon after A.D. 1200. This finding challenges previously held views of settlement dates of A.D. 400 and A.D. 1000.

Folklore emphasizes warfare and cannibalism as major factors in the civilization’s decline. Douglas Owsley, a forensic anthropologist at the Smithsonian Institution and a former student of Gill’s from Lusk, compiled data on skeletal injuries. The evidence shows most skeletal injuries were relatively minor, and just a small percentage were lethal. The data suggest that fighting might have occurred primarily as a show of dominance, without intending to kill. The samples examined do not support cannibalism, although it is possible that those bodies may have been burned.

“It leads us to believe that cannibalism wasn’t quite as rampant as some of the folklore indicates and that the ethnographers thought from the interviews,” Gill says. 

man at desk examining human skull
George Gill, a professor emeritus of anthropology at UW, studies a male skull that was discovered at a north coast site on Easter Island. (UW Photo)

Another concept that seems to be exaggerated is the amount of tribal difference, Gill says.

The research team’s craniometric studies show no difference among the different tribes. Gill’s continuous trait observation and other researchers’ DNA work show some measurable differences that can’t be explained just by geographic distance.

“There were some separations of tribes -- just not quite as great -- as some of the folklore indicates that they were totally separated, warring and they wouldn’t intermarry,” Gill says.

As for the mystery of how the Rapanui carved and moved the statues, Gill notes there’s no comment from the bone research on that.

In the book’s summary chapter, Gill and Stefan wrote: “We biologists have little to offer regarding statue production and transport, and will leave the resolution of those mysteries to the engineers and archaeologists!”

“Skeletal Biology of the Ancient Rapanui (Easter Islanders)” contains contributions from 20 scholars working in areas of study including biological anthropology, archaeology, genetics and DNA research. Published by Cambridge University Press, the book can be purchased at

About UW’s Easter Island Connection

William Mulloy, UW’s first professional anthropologist, was a member of the 1955-56 Norwegian expedition to Easter Island, led by Norwegian explorer Thor Heyerdahl. That field experience resulted in Mulloy’s archaeological research of the island for 23 years. In 1977, Mulloy and Gill, colleagues in the UW Department of Anthropology, began planning an Easter Island project that would focus on human skeleton research. During the planning phase, Mulloy contracted lung cancer and died in 1978.

Also, in 1978, Sergio Rapu, a native Rapanui who received a B.A. in anthropology from UW, and his cousin, Sonia Haoa, excavated 100 skeletons from the island. He contacted Gill for his help in analyzing the remains and joined the effort in organizing the research project.

Gill’s 37 years of Easter Island research began in 1979, when he and Rapu excavated 20 skeletons from threatened sites. Two years later, Gill, Rapu and Claudio Cristino, an archaeologist with the University of Chile, led an international research expedition to excavate and analyze Easter Island skeletons.

During that expedition and, in subsequent years, 14 UW students contributed to the research efforts. Some former students, including Stefan and Owsley, continue the research work.

About George Gill

Gill has excavated and studied several hundred human skeletons from tropical west Mexico, Easter Island and the Great Plains of North America. He has developed collections that form parts of the national museum collections of Mexico and Chile, and collections of the Office of the Wyoming State Archaeologist Repository.

Gill has been active in skeletal identification for law enforcement agencies. He is a Fellow of the American Academy of Forensic Sciences. Board certified by the American Board of Forensic Anthropology, he has served on the board of directors. He also is the former chair of the UW Department of Anthropology.

Gill has written nearly 100 journal articles and book chapters on skeletal biology and bioarchaeology. His research efforts in these areas have focused largely on population variation within Homo sapiens.

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