Human skulls from Thor Heyerdahl expedition cause controversy

In a box whose final destination is Easter Island lie 12 human skulls. Three of them have some tiny holes at the base of the ear canal. These almost invisible traces of research activity prompt big questions about the rights of Indigenous peoples and Thor Heyedahl’s posthumous reputation.

Thor Heyerdahl in the cave belonging to Esteban Haoa, along with Yvonne Heyerdahl
On Easter Island, Thor Heyerdahl was given access to a dozen or so secret caves, which had been used by their owners to store objects they considered sacred. Here is Heyerdahl in the cave belonging to Esteban Haoa, along with Yvonne Heyerdahl. (Photo: Kon-Tiki Museum)
forside bladet forskningsetikk nr 3 2019
Forskningsetikk nr 3, 2019 Magasinet Forskningsetikk er et uavhengig fagblad om forskningsetikk som utgis av De nasjonale forskningsetiske komiteene (FEK).

Peru, 28 April 1947: A balsawood raft sets sail from Callao in Peru with a crew of six. The objective is to reach Polynesia, an area of the Pacific Ocean dotted with islands and archipelagos. The skipper is 33-year-old Thor Heyerdahl.

The expedition is the result of a controversial theory that Heyerdahl has been ruminating on for ten years: Polynesia was not populated only by people arriving from the west, but also by native peoples from South America. Heyerdahl bases this theory on archaeological finds, observations of plant life and sea currents, and a legend of Kon-Tiki Viraccocha, the God of all Creation in pre-Inca and Inca mythology. According to the legend, Kon-Tiki Viraccocha sailed from Peru towards the west on a vast balsawood raft.

Many experts consider it highly unlikely that Heyerdahl’s expedition will reach its destination, but after 101 days at sea, the Kon-Tiki raft runs aground at Raroia, a small coral atoll in French Polynesia. Thor Heyerdahl and his crew had proved that native people from South American could have sailed to the Pacific islands on rafts made of balsa wood.

Heyerdahl later publicised a theory that Indigenous people from the Americas were the first to settle on Easter Island, the world’s most isolated inhabited island, which lies at the southeasternmost point of the Polynesian Triangle, some 3,700 km from the nearest mainland, Chile.

Heyerdahl’s success with Kon-Tiki is met by a tidal wave of criticism. His theories are pretty much torn to shreds by the rest of the scientific community. The prevailing theory is that Easter Island’s first inhabitants came from Asia via other Polynesian islands around 1200 CE, while native Americans arrived after Europeans had ‘discovered’ the island in 1722.

Oslo, 9 September 2019: The Magazine Research Ethics (Forskningsetikk) receives a text message: “I have received your e-mail. I will call you during the week. Regards, Erik Thorsby”

Thorsby is professor emeritus at the University of Oslo’s Department of Immunology and one of the people who have continued working on Heyerdahl’s Easter Island theory. Seventy years after the Kon-Tiki expedition, the theory has still not been confirmed.

Up until now, Thorsby has given brief answers when the magazine has been in touch: “We are in the middle of a process and various assessments. I cannot comment on the case right now.”

The ‘case’ is complex and has been ongoing for a long time. In brief, it centres on some rather contentious ‘souvenirs’ from one of Thor Heyerdahl’s expeditions: human skulls brought back from Easter Island in 1955–1956. After a year of archaeological excavation on the remote Pacific island, the hold of the expedition ship, MS Bjelland, was filled not only with hundreds of cave stones, sculptures and other cultural artefacts. Heyerdahl also brought to Norway human skulls and skeletal remains of people who lived on the island centuries ago.

Today, most of these items are held by the Kon-Tiki Museum. However, 12 of the skulls belong to the University of Oslo’s Schreiner Collections.

Thorsby believes that DNA obtained from tiny bone samples from the skulls could provide important answers about Easter Island’s first inhabitants. But is it ethically appropriate to take samples from and analyse the material? The National Committee for Research Ethics on Human Remains (the Human Remains Committee), which provides advice and recommendations of matters relating to research ethics, has been critical ever since Thorsby and his team first contacted it in 2013. Now there are signs that the researchers’ patience has run out.

Read the comment from the Human Remains Committee

Easter Island, 1971: Erik Thorsby arrives at Easter Island by plane. He wants to search for genetic traces of Indigenous Americans in today’s population. He collects blood samples from a carefully selected group of 69 islanders and analyses the samples for HLA molecules. Which variant of the molecule an individual has can give an indication of their genetic make-up – and therefore where they come from.

Back in Norway, Thorsby does not get the results he is hoping for. The HLA analyses produce no definite traces of Indigenous Americans on Easter Island.

Thorsby is farsighted and freezes the blood samples. In 2006, the technology has developed far enough. He thaws out the blood samples and, this time, performs DNA analyses, searching for HLA genes, not just molecules. His efforts pay off. Some of the blood samples contain variants of HLA genes that are otherwise only found in Indigenous Americans. Through genealogical studies and various genetic analyses, Thorsby and his team conclude that Indigenous American probably came to Easter Island before the Europeans.

Easter Island, 2008: Thirty-seven years have passed since Thorsby’s first visit to Easter Island. Now he is back. He takes new blood samples, which confirm the findings from those taken in 1971.

In 2012, he establishes a partnership with the Danish evolutionary geneticist Eske Willerslev to carry out more advanced genetic analyses on the samples. Once again, Thorsby finds what he is looking for. Some of the gene sequences in some of the blood samples are typical for Indigenous Americans. The results also show that some Indigenous Americans may have arrived on Easter Island as early as approx. 1340. In other words, some 100 to 150 years after the Polynesians first settled on the island, but long before the European explorers arrived.

The studies attract considerable attention and are cited in journals such as Science Magazine. Thorsby and his colleagues have proved that Heyerdahl was not entirely mistaken. Nevertheless, the findings are criticised. If the researchers are really to prove their case, analysis of blood samples is not enough. What is needed is DNA analysis of ancient skeletal remains which can be dated to the period before Europeans arrived on Easter Island. So-called ancient DNA (aDNA). That type of DNA could be found in the skeletal remains Heyerdahl brought back with him.

Oslo, December 2013: Thorsby’s research team do not get the Christmas present they had been hoping for. In its reply to Thorsby’s notice about examining the skulls, the Human Remains Committee writes that the project has the potential to produce interesting conclusions, which could arouse widespread international interest and engagement.

But the committee has objections, particularly relating to the material’s provenance: What were the circumstances surrounding the items and the site where they were found? Implicitly – did Heyerdahl acquire the skulls in an ethical manner?

Consent is another critical issue. Has the research team taken ‘adequate steps’ with regard to those who, with reasonable certainty, could be said to represent the persons or groups from which the remains derive?

Chile annexed Easter Island in 1888, and the island has a vexed history relating to explorers, colonisation and various expeditions. Both people and artefacts have been taken from the island by dubious means – through slavery and looting.

According to the Human Remains Committee, “Material of uncertain origin could have involved the abuse of individuals or groups.”

In its statement, the committee also points out that a number of major repatriation cases are underway. Here groups and peoples are demanding the return of artefacts that were exported for research purposes and inclusion in historical collections. In this context, the committee declared, a thorough job needed to be done to clarify relevant questions before embarking on any sampling or research.

Dead of night

The research team contacts the Human Remains Committee again in 2017 and 2018. Thorsby sets out the measures that have been implemented to discover the material’s provenance and what support his investigations have received from both the Easter Island Archaeological Museum (MAPSE) and the Kon-Tiki Museum in Oslo.

On both occasions, the Human Remains Committee’s conclusions are the same. There are strong indications that Heyerdahl removed the skulls without the local population’s consent. Research studies should not take place until the research team has examined the issue of provenance in more detail and an official representative of the local population on Easter Island has given permission for the studies to go ahead.

The committee place particular emphasis on a doctoral thesis about repatriation and reburial on Easter Island, written by Jacinta Arthur at the University of California, Lost Angeles (UCLA).

In her thesis, Arthur – who is herself from Easter Island – explains the high importance that human remains have for the native inhabitants. She claims that researchers have failed to understand this.

Arthur considers that Heyerdahl’s expedition engaged in “uncontrolled collection activities”. Quoting from Heyerdahl’s own books, she refers to descriptions of how the expedition’s members persuade a few natives to reveal secret caves containing sacred heirlooms; how they sneak around at the dead of night, and the cave-owners’ fear of how the local community will react.

Read Arthurs comment

In the book "Aku-Aku: The Secret of Easter Island", Heyerdahl writes about an episode where some native islanders have agreed to bring him a cave stone:

“Then came the night when Analola’s mother and Daniel Ika were supposed to steal to the cave. They came back the next morning with long faces, (...) they had not got down to the cave: they had found someone was spending the whole night in Vai-tara-kai-ua. The exact same thing happened the next night. By then they had seen that the mysterious person was old Timoteo. They had guessed that he had another cave there and that he was guarding the entrance, so Kon-Tiki’s people would not find it.”

28 February 2019: Media announce that the Kon-Tiki Museum has reached an agreement with the Chilean Ministry of Culture to repatriate material removed by Heyerdahl during the Easter Island expedition. A compelling point is an agreement that the material should be handed back after scientific analyses had been performed.

Read more: The Kon-Tiki Museum has the money ready

In principle, most of the material from Easter Island has the potential for repatriation. However, it is the human remains that the Kon-Tiki Museum wishes to hand back as quickly as possible.

It seems natural to imagine that the skulls held in the Schreiner Collections will be included in the consignment.

7 March 2019: The Human Remains Committee receives an e-mail from Thorsby:

“We also agree that it is a weakness in the project that we have been unable to document that Heyerdahl had the necessary permission to remove the materials from his digs for further study in Norway. Just before Christmas, the Kon-Tiki Museum found in its archives an agreement between Easter Island representatives, Thor Heyerdahl and Edwin Ferdon (a member of Heyerdahl’s expedition), signed 15 February 1956, in other words while Heyerdahl’s 1955–56 expedition was on the island.”

In the e-mail, Thorsby highlights the fact that one of the parties to the agreement was the then governor of Easter Island Arnaldo Curti, on behalf of the authorities on the island.

In conclusion, Thorsby writes: “It follows from this agreement that Heyerdahl had the necessary permission to collect the excavated material and bring it with him to Norway for further scientific study. The research team will therefore commence the aDNA analyses that are mentioned in our notice (...).”

The Human Remains Committee remains unconvinced, replying:

“This documentation does not alter the committee’s recommendation to the project, which is to obtain necessary consent from the local population on Easter Island.”

The committee underlines that a permit from the Chilean authorities is not sufficient.

“The committee therefore stands by its recommendation not to perform the planned research on the material before necessary permission from the local population has been obtained.”

After this, Thorsby goes quiet. What is happening with the project now? Are the Heyerdahl researchers still determined to start performing aDNA analyses?

11 September 2019: Thorsby is on the phone, ready to talk.

“For me, the most important thing in this case is whether we can say we have the necessary information about the skulls’ provenance and whether we believe we have consent to perform these analyses,” he says.

Thorsby describes the agreement from 1956 and the crucial significance he believes it plays in the issue of provenance.

The agreement says: “Having noted in general that the material excavated by the Norwegian Expedition is only of interest for scientific research, Mr Heyerdahl is authorised to take it away for the purpose of completing his research.” The decision was made on the basis of “knowledge of the report that was presented by Mr Thor Heyerdahl and with due ascertainment of the fieldwork that was carried out and an associated review of the excavated material.”

According to Thorsby, Heyerdahl would never have obtained this agreement if there had been any question that the material had been obtained unethically.

“So, you don’t think there can have been any asymmetric power balance at play here and that the views of the local population, for example, were not heard?

“I could never imagine such a thing! I have been to the island three times, and the respect in which Heyerdahl is held remains extremely high.”

“What do you think about Jacinta Arthur’s allegations about Heyerdahl’s behaviour?”

“I have found no evidence to support them. The 1956 agreement shows that the skulls were obtained in a completely ethical manner,” he asserts.

Thorsby considers the issue of provenance to have been cleared up.

“On this point, the Human Remains Committee’s demands for documentation are too strict,” he says.

Support from two museums

Thorsby believes that the agreement from 1956 provides implicit consent to perform research on the material. But DNA analysis is not explicitly mentioned.

“For that reason, we asked the Easter Island museum MAPSE and the Kon-Tiki Museum, and both strongly support our research” he points out, before adding:

“Because we were told by MAPSE that the family council on Easter Island was divided and no longer representative of the population, we did not send an enquiry to the council.”

The family council has therefore not expressed its opinion on the material in Oslo. However, in an e-mail to Thorsby, MAPSE points out that, until its division, the family council’s view was that research should not be carried out on human remains held at the museum on Easter Island.

Thorsby admits that he has not contacted other institutions or individuals, as the Human Remains Committee has suggested.

“I reason that the people from whom we took blood samples in 1971 and 2008, around 100 individuals, gave us informed consent to study the blood samples to find early genetic traces of Indigenous Americans. Obviously, this consent does not encompass the skulls in question now, but we have no reason to believe that the local population would object to our planned studies.”

Thorsby adds that another research team has published similar DNA analyses on skeletal material from the Kon-Tiki Museum, with permission from MAPSE and the Kon-Tiki Museum, and with the approval of the Ethics Committee at the University of Bristol in the UK.

“A line has to be drawn somewhere”

“So, we arrive at the big question: where does the project stand now?

“We have obtained some small samples from the skulls and carried out some preparatory analyses that are necessary before we can proceed. We have dated the skulls and our preliminary findings show that it is possible to extract satisfactory DNA from them. The actual DNA analyses to establish whether there are genetic traces of Indigenous Americans have not begun,” says Thorsby.

“The skulls are packed away and will soon be on their way to Easter Island along with the material from the Kon-Tiki Museum,” he adds.

Thorsby says that the samples were taken in 2012 and 2017.

“That means you took samples before the Human Remains Committee issued their statement in December 2018?

“Yes. We considered that we had the necessary information about provenance, and consent, at the very least to perform the very preliminary studies.”

Thorsby twice made it plain to the Human Remains Committee that he wanted a quick decision. What was so urgent that he did not even have time to wait for the committee’s statement?

“Several other research groups want to perform the same analyses that we do. We thought it would be nice to be the first to confirm our earlier findings, and that we in Norway could confirm that Thor Heyerdahl was not completely wrong. Indigenous Americans were not the first to settle on Easter Island, but they did arrive very early on,”
he says enthusiastically.

At the age of 81, Thorsby would love to conclude his research career by completing this project. Whether he will get his wish is another matter. He says that his research team is engaged in difficult assessments and has not come to a conclusion.

“Research ethics are extremely important, but not black and white. Different researchers can assess such issues in different ways. I believe we have abided by the Human Remains Committee’s recommendations as far as possible, but you have to draw the line somewhere. You can’t be more Catholic that the Pope.”


“Things have changed since the 1950s”

Jacinta Arthur has written a doctoral thesis on repatriation and reburial on Easter Island. Her thesis also addresses Thor Heyerdahl’s expedition. She says that there is a certain amount of collective resistance to research on human remains among the island’s indigenous people.

“This resistance is rooted in both ethical questions and the importance that human remains have for the person’s descendants. Ancestors are considered holy, so most people don’t want them to be destroyed,” says Arthur.

When Forskningsetikk tells her about Erik Thorsby’s research project, her first response is:

“I’m surprised that a researcher is using a contract from 1956 as an argument. Things have changed a lot with regard to research ethics and the rights of Indigenous peoples. Nowadays, the indigenous Easter Islanders have a voice when it comes to these questions, particularly questions relating to human remains.”

Arthur believes Thorsby and others who plan to study similar material should, at least, obtain informed consent from affected groups.

“Then the researchers should negotiate a suitable methodology and actually comply with those demands,” she asserts.

According to Arthur, a new family council (Honui) has recently been established, with representatives from all the 36 original families on the island. She recommends that researchers send an application to this council. To ensure that research complies with Chilean law, the advisory committee to the National Monuments Council must also give its permission.

Go back to the main article.

The Human Remains Committee: Puts the research in a strange light

“We believe that the research team has not done enough to engage in a dialogue with and obtain the consent of the Indigenous inhabitants’ representatives,” says Nils Anfinset, who chairs the Human Remains Committee.

Anfinset agrees that the 1956 contract that Thorsby attaches such importance to is relevant. In his view, however, it is not sufficient to clarify the questions the committee has asked the project.

“The contract does to some extent illuminate the issue of provenance. At the same time, there were probably other considerations in play when the remains were brought to Norway in 1956 than the opportunities that have emerged in the past 10 to 15 years relating to genetics.

These are challenges that Thorsby and his partners should reflect on,” he says.

“An important point for us has also been that the researchers must contact the local population. This has not been done, after repeated remarks from our side.”

Undesirable consequences

Anfinset explains that research into material relating to Indigenous peoples is complicated. Different Indigenous groups have different ideas about the significance of skeletal material and how it should be handled. There may be different interests even within a group, so it is important to talk to numerous different people and bodies.

“It is about the right to say yes or no in matters regarding research projects. Research on this type of material could have highly undesirable consequences, which may be overlooked in connection with sampling and the publishing of such data. It could unsettle cultural beliefs relating to history, ethnicity, migration and myths that create cohesion within a group.”

Vulnerable Indigenous people

Anfinset explains that the Human Remains Committee is an advisory body and that it is up to the researchers themselves to consider whether they will accept its advice.

“Nevertheless, I think it is a bit surprising that Thorsby and his colleagues are not taking more notice of what the Human Remains Committee has said. It puts their research in a rather strange light.”

“What is your reaction to Thorsby’s claim that the Human Remains Committee is being too strict?”

“Our role is absolutely not to hamper research, but to promote research ethics. In this case, the point is to take account of the Indigenous population in a vulnerable situation,” says Anfinset in conclusion.

Back to main article

The Kon-Tiki Museum has the money ready

If Erik Thorsby produces a permit from the museum on Easter Island, that is good enough for the Kon-Tiki Museum. In that case, the NOK 200,000 granted by the museum’s board will be paid into his account.

Thorsby’s submission to the Human Remains Committee in October 2018 was accompanied by a letter of recommendation from the Kon-Tiki Museum:

“The Kon-Tiki Museum recommends that samples from the material be used for DNA analysis to determine whether the Polynesian population on the island had contact with people from the South American continent.”

On 13 December that same year, the Kon-Tiki Museum allocated NOK 200,000 in funding for the project. The money will be paid out when Thorsby provides the museum with the “necessary permits to perform DNA analyses on the skulls”.

Ingjerd Hoëm, who chairs the Kon-Tiki Museum’s board of directors, says that they are interested in the Human Remains Committee’s views. Nevertheless, the museum considers that it is up to the researchers to assess what is acceptable from a research ethics perspective and which permits are necessary.

"A difficult question"

“For us, it is important that the consent of those concerned has been obtained. When it comes to skeletal remains from unnamed individuals, it is a difficult question,” says Hoëm.

It would, however, be sufficient if Thorsby were to receive written permission from the archaeological museum on Easter Island, MAPSE, according to the Kon-Tiki Museum’s chair.

“The board is of the opinion that MAPSE is the highest legitimate authority at the moment. If they support a research project, that is good enough for us,” says Hoëm.

Like Thorsby, she does not believe there are any grounds to question the ethics of Heyerdahl’s collection methods given the standards of the day.

At the same time, Hoëm underlines that the museum is keen to return the material which, according to the contract, was a loan.

“The repatriation of materials that come from Easter Island, including parts of the Schreiner Collections, is proceeding independently of any research plans and is our highest priority.”