African Elephants’ Death Mystery Explained But Sparks More Questions

By: Past Chronicles Staff | Published: Apr 01, 2024

In 2020, many elephants died in Africa. Between August and November of that year, 35 elephants died in Zimbabwe. Months before, in neighboring Botswana, 350 elephants also died in the span of several months.

The deaths of these mammoth animals have been a mystery until late 2023. According to scientists, their deaths are connected to blood-poisoning bacteria.

Cause of Death in Zimbabwe

Publishing their findings in Nature Communications, a team of scientists led by Dr. Chris Foggin, a veterinarian at Victoria Falls Wildlife Trust in Zimbabwe, took samples from the dead elephants to determine the cause of death.

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A carcass of adult African elephant in between the trees on dry ground

Source: Gerardshields11/Wikimedia Commons

In the case of the Zimbabwean elephants, a bacterial infection caused their deaths. The bacteria, called Pasteurella Bisgaard taxon 45, caused septicemia, or blood poisoning.

The Killer Bacteria

The Pasteurella also caused the deaths of saiga antelopes in Kazakhstan in 2015. Dr. Arnoud van Vliet of University of Surrey noticed similarities in the strains found in Kazakhstan and in Zimbabwe.

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A magnified shot of numerous Pasteurella multocida bacteria

Source: Dr. R. Weaver/Wikimedia Commons

While the bacteria can live harmlessly in some species, when the external temperature heats up to 37 degrees Celsius, the bacteria move into the bloodstream. This is what causes the blood poisoning.

A Different Cause in Botswana

However, in the case of the Botswana elephants, the cause may be different. Foggins said there was no proven connection between the elephants in the two countries.

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Animals in the wild in Okavango Delta, Botswana

Source: Secret Travel Guide/Unsplash

The deaths of the hundreds of elephants in Botswana were largely attributed to an attack to their nervous systems. A cyanobacterial neurotoxin caused their demise based on tests by Botswana’s authorities.

Okavango Delta’s Mystery

Mmadi Reuben, Principal Veterinary Officer for Botswana’s Department of Wildlife and National Parks explained that cyanobacterial neurotoxins were found in water, which the elephants might have drunk from. But another mystery remains: Why were elephants the only animals affected?

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An aerial shot of the Okavango River

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After all, the habitat in Okavango Delta is diverse. There are 530 species of birds, 160 species of mammals, and other reptiles, amphibians, and plants. While the African elephant is a keystone species in Okavango Delta, so is hippopotamus. And yet, there have been no reports of mass hippopotamus deaths.

Ongoing Deaths in the Delta

The single location of Botswana’s Okavango Delta also still brought up questions. Authorities have yet to answer why only elephants in that particular location were affected.

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An elephant by the side of the water in Okavango, Botswana

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In 2022, researchers in the Kavango-Zambezi Conservation Area, which includes the delta, still found a high number of elephant carcasses. Laura Rosen, a co-author of the report in Nature Communications journal, suggested further investigations into the bacteria.

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Possibility of an Extinction Event

There is a speculation that whatever was affecting the elephant herd could also spill over to the human population.

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A herd of elephants walking through the land

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Dr. Niall McCann, Conservation Director for the National Park Rescue organization, even had more dire predictions: “Until we know that this is no longer a danger to the herd, there is the prospect of Botswana’s entire herd being decimated.”

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Blame It on Climate Change

Another factor to these deaths must also be considered: climate change. Researchers noted that the blood poisoning in Zimbabwe’s elephants came during the dry season.

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Tree with dry branches, behind other tree's with fresh green branches and leaves in Nigeria

Source: Dorothy Habila/Wikimedia Commons

The heat, drought, and population density in the area might have been an influential factor in the bacteria’s outbreak.

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A Worry for the Future

However, Foggin insisted that blaming climate change as a cause for these deaths might be premature.

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Dry clay soil in Africa

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Only if the area experiences a much harsher dry season, with extended periods of droughts and changes to rainfall patterns, is it more likely for this “mortality event” to recur.

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Illegal Poaching Is a Problem

Sadly, African elephants won’t have an easy future. This flagship species has already entered the International Union for Conservation of Nature Red List.

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Two men holding rifles in the jungle

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It’s not just habitat loss that is wreaking havoc with their existence; poaching is also to blame. Fortunately, there are anti-poaching measures active to prevent the further destruction of the animal population.

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Struggles in Investigation

Despite the discovery of the bacteria causing elephant deaths, details are still vague about whether this disease is an all-encompassing concern. Difficulties in examining the carcasses still posed problems in general for the researchers.

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A driver in a safari car facing a herd of elephants

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Dr. Foggin stated in a press release that they had to be “cautious when undertaking the post-mortem examinations on elephants.” It is, he said, a difficult task with the animal’s size and the field conditions.

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More Studies Are Imperative

But tremendous efforts must be made into studying more of the bacteria found in these elephants before a larger tragedy occurs. 

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Two hippopotamus in the water with their mouths open

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Van Vliet cautioned, “There may be other animals where this could become a problem. If we don’t look for it, we won’t know whether it is there. If it is present in other wildlife, we may see other unexpected deaths.” 

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