In 1533, a famous Portuguese trading vessel called the Bom Jesus went missing on its way to India. It sank off the coast of present-day Namibia while it was filled with more than 40 tons of precious cargo, including gold, silver, copper, and more than 100 elephant tusks. Scientists traced the origins of much of the ivory that was recovered from the shipwreck, revealing more about the ancient ivory trade and African elephants of the past and present.
The Treasures of the Bom Jesus Shipwreck
The Bom Jesus shipwreck was found in 2008. It is the “oldest known shipwreck in southern Africa” according to CELL. It is also known as the ‘Diamond Shipwreck’ because its location is near diamond mines. The shipwreck has provided a wealth of archaeological treasures.
Treasures from the Bom Jesus shipwreck. Top: gold 10- cruzado coins (cross insignia), minted under the reign of King João III of Portugal in 1525 and withdrawn in the 1530s, helped to date and identify the ship. Bottom: the shipwreck cargo included more than 100 unworked elephant tusks. (Amy Toensing; National Geographic Image Collection license)
Some of the artifacts have been kept in damp storage since they were found, such as timber, muskets, cannonballs, and swords. Apart from these objects, the researchers also found armor, pewter bowls, the elephant tusks, 22 tons of copper ingots, and a large quantity of gold. As Ancient Origins previously reported on the discovery, “The gold was in the form of coins, more than 2,000 in total, mainly Spanish excelentes bearing the likenesses of the monarchs Ferdinand and Isabella, but also some Venetian, Moorish, French and other coinage.”
Archaeologist Dieter Noli, who worked on the shipwreck when it was first discovered, said that the Portuguese vessel sank after striking a rock near the African coastline known for dangerous seas and storms. Following the collision, Noli said that the ship, “started breaking up and the chest with the coins was in the captain’s cabin, and it broke free and fell to the bottom of the sea intact… In breaking up, a very heavy part of the side of the ship fell on that chest and bent some of the coins. You can see the force by which the chest was hit, but it also protected the chest.”
Artist’s depiction of an ancient ship in trouble. (Art by Jon Foster)
An international research team behind the study published in 2020 in the journal Cell – Current Biology, includes Alida de Flamingh, Alfred Roca, and Ripan Malhi of the University of Illinois and Ashley Coutu and Shadreck Chirikure, who are affiliated with the University of Oxford and University of Cape Town. Lead researcher de Flamingh said that the cache of elephant tusks was stowed in a lower level of the Bom Jesus “under a weighty cargo of copper and lead ingots.” de Flamingh explained that this was beneficial in preserving the artifacts:
“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. 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.”
Analyzing the Elephant Tusk DNA
Science magazine explained that the researchers had “plenty of genetic material to work with” 12 years after the shipwreck discovery. The goal of the research was to “pinpoint the source of elephant ivory that was widely circulated in the Indian and Atlantic trading systems during early trade and globalization.”
To accomplish this task, the study stated that it is the first of its kind “to combine paleogenomic, isotopic, archeological, and historical methods to determine the origin, ecological, and genetic histories of shipwrecked cargo.”
One of the key elements of the research was to extract the DNA from 44 elephant tusks. The scientists used that genetic material to determine that that the ivory came from 17 distinct herds of forest elephants. de Flamingh explained how they came to this conclusion, stating:
“Elephants live in female-led family groups, and they tend to stay in the same geographic area throughout their lives. 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.”
This photo shows an African forest elephant (Loxodonta cyclotis). (Nicholas Georgiadis)
A Surprise Regarding Portuguese Trading Habits in the 16th Century
A University of Illinois at Urbana-Chambaign report stated that only four of the 17 elephant family lineages are known to still exist in Africa. The elephant tusk analysis also showed that all of the samples originated in West Africa, none of them were from elephants which had lived in Central Africa. de Flamingh noted that “This is consistent with the establishment of Portuguese trading centers along the West African coast during this period of history.”
However, study co-author Chirikure also pointed out that the lack of elephant tusks originating in Central Africa was a surprise because by the 16th century the Portuguese had already established trade connections with the Kongo Kingdom and communities along the Congo River. “The expectation was that the elephants would be from different regions, especially West and Central Africa,” Chirikure said. Ivory was highly valued in the trans-continental commercial trading system which connected Europe, Africa, and Asia maritime routes in the 16th century, so it is interesting to discover the origins of this important trade item.
Terrestrial vegetation and Portuguese trading posts in the late 15th and early 16th century. (de Flamingh et al./ Current Biology 2020)
Final Thoughts Stemming from the Elephant Tusk Research
Isotope analyses of the elephant tusks also suggested that the elephants lived in mixed forest habitat. Roca provided the significance of this find to understanding past and current lives of African elephants, “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 said. “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.”
de Flamingh said that the multidisciplinary nature of this research also “provides a framework for examining the vast collections of historic and archaeological ivories in museums across the world.” This type of study could be applied to future analyses of elephant tusks which have been recovered from other shipwrecks or different archaeological contexts as well. As Coutu says, “The revelation of these connections tell important global histories.”
Couto also pointed out that the study provided a better understanding of “the ecology of the West African forest elephant in its historic landscape,” which can help with modern wildlife conservation and finding the sources of confiscated illegal ivory.