Shipwrecked ivory a treasure trove for understanding elephants and 16th century trading

CELL PRESS

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IMAGE: THIS PHOTO SHOWS AN AFRICAN FOREST ELEPHANT (LOXODONTA CYCLOTIS). view more 

CREDIT: NICHOLAS GEORGIADIS

In 1533, a Portuguese trading vessel carrying forty tons of gold and silver coins along with other precious cargo went missing on its way to India. In 2008, this vessel, known as the Bom Jesus, was found in Namibia, making it the oldest known shipwreck in southern Africa. Now, an international collaboration of researchers in Namibia, South Africa, the United Kingdom, and the United States reporting in the journal Current Biology on December 17 have found that the ship's cargo included more than 100 elephant tusks, which paleogenomic and isotopic analyses trace to many distinct herds that once roamed West Africa.

The study is the first to combine paleogenomic, isotopic, archeological, and historical methods to determine the origin, ecological, and genetic histories of shipwrecked cargo, according to the researchers. That's noteworthy in part because ivory was a central driver of the trans-continental commercial trading system connecting Europe, Africa, and Asia via maritime routes. The findings also have implications for understanding African elephants of the past and present.

In the new study, the team, including Alfred L. Roca and Alida de Flamingh, University of Illinois at Urbana-Champaign, along with Ashley Coutu and Shadreck Chirikure, affiliated with the University of Oxford and University of Cape Town, wanted to pinpoint the source of elephant ivory that was widely circulated in the Indian and Atlantic trading systems during early trade and globalization.

"Elephants live in female-led family groups, and they tend to stay in the same geographic area throughout their lives," de Flamingh explains. "We determined where these tusks came from by examining a DNA marker that is passed only from mother-to-calf and comparing the sequences to those of geo-referenced African elephants. By comparing the shipwreck ivory DNA to DNA from elephants with known origins across Africa, we were able to pinpoint the geographic region and species of elephant with DNA characteristics that matched the shipwreck ivory."

"In order to fully explore where these elephant tusks originated, we needed multiple lines of evidence," Coutu adds. "Thus, we used a combination of methods and expertise to explore the origin of this ivory cargo through genetic and isotopic data gathered from sampling the tusks. Our conclusions were only possible with all of the pieces of our interdisciplinary puzzle fitting together."

The team's analyses, including DNA from 44 available tusks and isotope analysis of 97 tusks, showed that the ivory had come from African forest elephants. Their mitochondrial DNA, passed down from mother to calf, traced them to 17 or more herds from West as opposed to Central Africa. That was a surprise, Chirikure says, because the Portuguese had established trade with the Kongo Kingdom and communities along the Congo River by the 16th century. "The expectation was that the elephants would be from different regions, especially West and Central Africa."

Four of the mitochondrial haplotypes they uncovered are still found today in modern elephants. The others may have been lost due to subsequent hunting for ivory or habitat destruction. Isotope analyses also suggest the elephants lived in mixed forest habitat, not deep in the rainforest, the researchers report.

"There had been some thinking that African forest elephants moved out into savanna habitats in the early 20th century, after almost all savanna elephants were eliminated in West Africa," Roca says, noting that savanna elephants represent a distinct elephant species. "Our study showed that this was not the case, because the African forest elephant lived in savanna habitats in the early 16th century, long before the decimation of savanna elephants by the ivory trade occurred."

In addition to these insights, De Flamingh says that these new data can now aid in tracing the source of confiscated illegal ivory. And the new findings are just the tip of the iceberg in terms of what can be learned from studies of ivory about elephants and the people who hunted them.

"There is tremendous potential to analyze historic ivory from other shipwrecks, as well as from archaeological contexts and museum collections to understand the life histories of elephant populations, the skills and lifeways of the people who hunted and traded the ivory, as well as the many journeys of African ivory across the world," Coutu says. "The revelation of these connections tell important global histories."

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This work was supported by USFWS African Elephant Conservation Fund, South African Research Chairs Initiative of the National Research Foundation and Department of Science and Technology of South Africa, NRF, USDA ILLU 875-952 and ILLU-538-939, PEEC and Clark Research Support Grants, Claude Leon Foundation, and the European Union.

Current Biology, de Flamingh et al.: "Sourcing elephant ivory from a 16th century Portuguese shipwreck" https://www.cell.com/current-biology/fulltext/S0960-9822(20)31663-8

Current Biology (@CurrentBiology), published by Cell Press, is a bimonthly journal that features papers across all areas of biology. Current Biology strives to foster communication across fields of biology, both by publishing important findings of general interest and through highly accessible front matter for non-specialists. Visit: http://www.cell.com/current-biology. To receive Cell Press media alerts, contact press@cell.com.

CAPTION

From left, animal sciences professor Alfred Roca, postdoctoral researcher Alida de Flamingh and anthropology professor Ripan Malhi led a team that analyzed DNA extracted from elephant tusks recovered from a 16th century shipwreck. Composite image from separate photos, in compliance with COVID-19 safety protocols.

CREDIT

Photo by L. Brian Stauffer

Study tracks elephant tusks from 16th century shipwreck

UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN, NEWS BUREAU

Research News

 

CAPTION

This photo shows Raw elephant tusks from the 16th century Bom Jesus shipwreck.

CREDIT

National Museum of Namibi

IMAGE: A NEW STUDY ANALYZED THE LARGEST ARCHAEOLOGICAL CARGO OF AFRICAN IVORY EVER FOUND, RESEARCHERS REPORT. ALL OF THE ELEPHANT TUSKS WERE FROM AFRICAN FOREST ELEPHANTS, LOXODONTA CYCLOTIS. view more 

CREDIT: PHOTO BY NICHOLAS GEORGIADIS

CHAMPAIGN, Ill. -- In 1533, the Bom Jesus - a Portuguese trading vessel carrying 40 tons of cargo including gold, silver, copper and more than 100 elephant tusks - sank off the coast of Africa near present-day Namibia. The wreck was found in 2008, and scientists say they now have determined the source of much of the ivory recovered from the ship.

Their study, reported in the journal Current Biology, used various techniques, including a genomic analysis of DNA extracted from the well-preserved tusks, to determine the species of elephants, their geographic origins and the types of landscapes they lived in before they were killed for their tusks.

The ivory had been stowed in a lower level of the Bom Jesus under a weighty cargo of copper and lead ingots, said Alida de Flamingh, a postdoctoral researcher at the University of Illinois Urbana-Champaign who led the study with U. of I. animal sciences professor Alfred Roca and anthropology professor Ripan Malhi.

"When the ship sank, the ingots compressed the tusks into the seabed, preventing a lot of physical erosion by sea currents that can lead to the destruction and scattering of shipwreck artifacts," de Flamingh said. "There is also an extremely cold sea current in that region of coastal Namibia, which likely also helped preserve the DNA in the shipwrecked tusks."

The team extracted DNA from 44 tusks.

By analyzing genetic sequences known to differ between African forest and savanna elephants, the scientists determined that all of the tusks they analyzed belonged to forest elephants. A further examination of mitochondrial DNA, which is passed only from mothers to their offspring, offered a more precise geographic origin of the elephant tusks than is otherwise available.

"Elephants live in matriarchal family groups, and they tend to stay in the same geographic area throughout their lives," de Flamingh said. "By comparing the shipwrecked ivory mitochondrial DNA with that from elephants with known origins across Africa, we were able to pinpoint specific regions and species of elephants whose tusks were found in the shipwreck."

All 44 tusks were from elephants residing in West Africa. None originated in Central Africa.

"This is consistent with the establishment of Portuguese trading centers along the West African coast during this period of history," de Flamingh said.

The team used DNA to trace the elephants to 17 family lineages, only four of which are known to persist in Africa.

"The other lineages disappeared because West Africa has lost more than 95% of its elephants in subsequent centuries due to hunting and habitat destruction," Roca said.

The team is adding the new DNA sequences to the Loxodonta Localizer, an open-access tool developed at the U. of I. that allows users to compare mitochondrial DNA sequences collected from poached elephant tusks with those in an online database collected from elephants across the African continent.

To learn more about the environments the elephants inhabited, Oxford University Pitt Rivers Museum research fellow and study co-author Ashley Coutu analyzed the stable carbon and nitrogen isotopes of 97 tusks. The ratios of these isotopes differ depending on the types of plants the elephants consumed and the amount of rainfall in the environment.

That analysis revealed that the elephants lived in mixed habitats, switching from forested areas to savannas in different seasons, most likely in response to water availability.

"Our data help us to understand the ecology of the West African forest elephant in its historic landscape, which has relevance to modern wildlife conservation," Coutu said.

"Our study analyzed the largest archaeological cargo of African ivory ever found," de Flamingh said. "By combining complementary analytical approaches from multiple scientific fields, we were able to pinpoint the origin of the ivory with a resolution that is not possible using any single approach. The research provides a framework for examining the vast collections of historic and archaeological ivories in museums across the world."

de Flamingh conducted the DNA analysis in the Malhi Molecular Anthropology Laboratory at the Carl R. Woese Institute for Genomic Biology at the U. of I. This project was a multi-institutional effort involving collaborators in Namibia, South Africa, the United Kingdom and the U.S.

CAPTION

This photo shows the sampling team of technicians and curators from the National Museum of Namibia and archaeologists from the University of Cape Town: (L-R) Dawid Kapule, Judith Sealy, Nzila M. Libanda-Mubusisi, Virimuje Kahuure, Fouzy Kambombo, , Eliot Mowa, Ashley Coutu and Henry Nakale.

CREDIT

Shadreck Chirkure

The U.S. Fish and Wildlife Service African Elephant Conservation Fund, U.S. Department of Agriculture, National Research Foundation of South Africa, Department of Science and Technology of South Africa, and Claude Leon Foundation supported this research.

Editor's notes:

To reach Alida de Flamingh, email deflami2@illinois.edu.

To reach Alfred Roca, email roca@illinois.edu.

To reach Ripan Malhi, email malhi@illinois.edu.

To reach Ashley Coutu, email ashley.coutu@prm.ox.ac.uk.

The paper "Sourcing elephant ivory from a 16th century Portuguese shipwreck" is available from the U. of I. News Bureau.
[LINK to email: news@illinois.edu]