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Shipwrecked ivory and its clues for elephant conservation

In 1533, a Portuguese trading vessel, named Bom Jesus, set sail for India. Sailing down the west coast of Africa and laden with forty tons of gold and silver coins, as well as 100 elephant tusks, the ship ran afoul a large storm and sank off the coast of Namibia.

Nearly 500 years later the ship has been discovered again, triggering a huge international collaboration of scientific mystery solvers, combining archaeological, paleo-isotopic, historical and ecological methods to better understand the contents onboard this sunken vessel. Interestingly, the information gleamed from what remains on the ship may provide valuable insights that could help modern day elephant conservation.

A brief history of the ivory trade

The ivory trade has a dark and extensive history, driven by the demand for elephant tusks for medicinal and ornamental purposes. It began with the exploitation of North African elephants to supply ivory to the Roman Empire, and the trade escalated, leading to the near-extinction of elephants in the area by the 4th century.

Although the trade briefly declined, it resurged during the medieval era, with West and East African ivory traded through trans-Saharan routes and coastal networks to reach Europe and Asia. By the 1400s, Portuguese traders had entered the fray on the West Coast, prompting increased in-land hunting as coastal elephant populations dwindled.

The following centuries witnessed a brutal convergence of ivory trade and slavery along the East African coast, exacerbated by European hunters in the 1800s. Despite early attempts at regulation through colonial game laws, poaching persisted. It wasn’t until 1990 that African elephants, with exceptions, received protection under the Convention on International Trade in Endangered Species. Today, elephant’s are still poached on a mass scale, with an estimated 30,000 African elephants lost every year. 

Decoding the ivory: insights into past elephants

Due partly to the weight of the ingots on board pushing the ivory into the sea floor as well as ocean currents maintaining a cool temperature, the ivory on Bom Jesus was surprisingly well preserved 500 years later. This meant that scientists could extract and analyse the DNA from the tusks, giving them remarkable insights into where the elephants came from.

From cells inside the tusks they found that it actually came from African forest elephants, a distinct species to the larger, more common savannah elephant we find here in Tsavo.

Next, the scientists analysed the tusk’s mitochondrial DNA, which is passed down from mother elephants to their calves, and can be used to figure out where elephants originated.

They discovered that the tusks came from 17 distinct elephant herds, originating from West Africa. This gives clues at the extent of elephant hunting happening in the 1500s, where numerous herds were being hunted by many different communities along the West African coast.

Interestingly, the researchers managed to find that 4 of the 17 herds identified, have living relatives still around today. The loss of the other 13 is indicative of the populations of elephants lost to poaching and habitat loss over the centuries. In fact, African forest elephants are still suffering from sharp population decline, according to the IUCN the number of forest elephants fell by more than 86% between 1989 and 2020.

If you would like to learn more about African forest elephants and how they shape the tropical rainforests of Africa, follow this link.

By studying the carbon and nitrogen isotopes of the tusks, the researchers were able to identify the specific habitat the elephants lived in. They found that, contrary to most African forest elephants today, these populations actually lived not in the deep tropical forests, but in a mixed woodland and savanna environment.

Although, some forest elephants dwell in these habitats today, experts thought this was as a result of the savanna elephant’s populations being largely wiped out and the forest elephants moving in to replace them. However, this discovery could suggest that forest elephants have resided in savanna-like environments for a long time. This could change the way the ecologists understand forest elephants and therefore the conservation strategy for these animals.

Clues for conservation

The incredible detective work by this collaboration of scientists has given valuable insights into the historical ivory trade along the West African coast, as well as substantially adding “to the relatively scarce genetic data available for forest elephants”.

500-year-old, ivory, shipwrecked and seemingly lost forever is now providing important information for “human history,  elephant genetic diversity and ecology and biodiversity conservation”.

It also highlights the plight of African elephants, with both savanna and forest elephants being relentlessly hunted for so many years for their ivory. However, it serves as a reminder of this amazing animal’s resilience and adaptivity. These creatures, despite intense hunting over centuries, have managed to survive, and still thrive, in some protected areas of Africa. Showing that if we maintain protected habitats, such as the Tsavo Conservation Area, we will be able to keep these remarkable creatures.

The remarkable discovery of 500-year-old shipwrecked ivory from the Portuguese trading vessel Bom Jesus has provided invaluable insights into both the historical ivory trade along the West African coast and the complex dynamics of elephant populations in Africa. Through a collaborative effort of scientific disciplines spanning archaeology, genetics, and ecology; researchers have pieced together a narrative of human history, elephant genetic diversity, and ecological adaptation.

If you would like to help support Tsavo Trust in protecting and monitoring some of the amazing wildlife that call Tsavo Conservation Area home, including some of the world’s few remaining big tuskers, then follow this link.

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