‘It's too early to rule anything out.’ The race to explain Botswana’s elephant catastrophe

From poaching to COVID-19, the scale of this 'unprecedented' elephant die-off could have an array of causes – and devastating effects.

By Simon Ingram
Published 7 Jul 2020, 09:48 BST, Updated 25 Nov 2020, 14:29 GMT

Aerial images over Botswana show the bodies of African elephants of all ages struck down by a mysterious cause. Theories range from disease to poisoning – but the logistical difficulty in trying to access the carcasses has made definitive identification of the culprit difficult. Now it is feared further delay may result in yet more deaths – which are thought to number at least 275.  

Photograph by Supplied

PRONE on the ground, their skin baking and crumpling around the bones beneath, the aerial images released last week of elephants lying dead on the savannah of Botswana were as shocking as they were mysterious. For a species long an icon of conservation, the sudden appearance of so many African elephants of all ages lifeless and decomposing in what has long been a stronghold of the population has baffled scientists and conservationists. Now all are scrabbling to understand a so-far unidentified cause both to prevent further death of this vulnerable species – or potentially contain a wider health emergency. 

For the catastrophe to be unfolding during the logistical restrictions of a global pandemic makes things all the more desperate – as well as offering the chilling possibility that the two may be linked. 

“It is too early to rule anything out, including COVID-19,” says Dr Niall McCann, Director of Conservation for National Park Rescue, and a National Geographic Explorer. “We already know that COVID-19 can be transmitted from humans into big cats,” he says, adding that other pathogens have also jumped from people back into animals along a little-studied pathway known as 'reverse zoonosis.'

Either way, he says, the issue is should have a response governed by the learnings of recent global happenings. “The whole world has ground to a halt due to a zoonotic spillover event, so it is vital that we identify the cause of this tragedy as soon as possible, to eliminate the possibility of it [spreading] into the local human population.” 

Causes unknown 

Reports of an unusual number of elephant carcasses – 12 initially – spotted from aerial surveys began in mid-May. By July 3 that had risen to at least 275 confirmed deaths and as many as 375, mostly in the Okavango Delta region of the country’s north. While elephants have died in large numbers before, causes have typically been easily identifiable according to McCann. Drought in particular was responsible for the deaths of some 6,000 elephants over 4 years in Tsavo National Park in the early 1970s. But “in terms of a single event, taking place over only a few weeks [and] killing such a huge number of elephants, this is completely unprecedented,” he says.

McCann believes the deaths are probably linked to one of three types of culprit. Firstly a pathogen, which – COVID-19 aside – could run a gauntlet of potential candidates. These include prion disease, a family of degenerative neurological conditions which include the human illness Creutzfeldt-Jakob disease, (CJD); encephalomyocarditis, a cardiovirus spread within mammals which affects the cardiovascular and pulmonary systems; or elephant endotheliotropic herpesvirus, which causes a range of haemhorragic diseases. Any of these “could induce the symptoms we are witnessing in the dead and dying elephants,” McCann says. Signs observed in elephants believed to be afflicted with the mysterious malady include confusion, walking in circles, weakness and emaciation, and limping. Some of the deceased animals show evidence of falling forward on their face, however – a sign of more sudden death, rather than a slow decline.  

Aerial view of African elephants, in the Okavango Delta, Botswana. The region has been referred to as the ‘last safe haven’ for the species, though last year the ban on hunting was lifted in Botswana after a five-year suspension.   

Photograph by Michael S. Nolan, Alamy

Another cause could be a naturally occurring toxin such as anthrax, or cyanobacteria, commonly called blue-green algae, being consumed – though both theories have flaws. Outbreaks of anthrax in Botswana killed dozens of elephants in October 2019, but its occurrence in animals is typically linked to drought, and caused by its bacterial spore being ingested by thirsty elephants eating dirt. Botswana currently has no drought, and is emerging from its rainy season. Cyanobacteria also seems unlikely due to the incident’s apparent specificity to elephants, rather than any creature that shares their water source. 

The third possibility is that the elephants have been poisoned by humans. Human-elephant conflict is commonplace and costly, in Botswana: elephants can destroy crops and be aggressive, forcing them into frequent clashes with farmers. Then there is poaching, inevitably the reflexive culprit when an animal associated with illegal trade is pictured dead. But if a poison is involved, the most common candidate is questionable. “Cyanide stays in the system for up to 72 hours, so we would expect to see dead scavengers lying around the bodies of the elephants, which we are not seeing,“ says McCann. However he notes “other poisons such as aluminium phosphide do not tend to affect secondary consumption, so scavengers wouldn’t be affected.” For a material that illegally fetches high prices on the black market, were poaching the culprit it is also peculiar that many of the carcasses – some of which are many weeks old – still have their tusks intact.

“For now we have to assume that every elephant in this region is at risk. Which is a terrible thought.”

Dr Niall McCann

Slow progress

Botswana’s elephant population is the highest in the world, with an estimated 130,000 savannah elephants – comprising around a third of the total African population. Long considered the species’ ‘last safe haven,’ recent years have seen a controversial series of decisions by Botswana’s new government. Its disarming of anti-poaching units in 2018 was believed by a local conservation body to be linked to a spike in country-wide killings and ivory trafficking – estimating that at least 385 elephants were poached in Botswana from 2017 through to early October 2018.

The link was refuted as ‘hysteria’ by the country’s president Mokgweetsi Masisi – who, later in 2019, lifted the country’s five-year ban on hunting animals including elephants, claiming in a statement ‘the number and high levels of human-elephant conflict and the consequent impact on livelihoods was increasing.’ 

Like most other absolutes in this case, whether poaching is to blame for the recent deaths remains to be established. And while action of any kind appears slow, some have cautioned against simply blaming the government’s response for six-week delay in definitive results. 

“This is pretty remote country,” Chris Thouless, head of research at Save the Elephantstold Reuters last Friday. “Hearing about the carcasses, getting in there, taking a whole range of samples, knowing how and where to get them from… [it’s] a pretty difficult task.”

“There are lots of issues to deal with, ease of movement being just one of them,” says Niall McCann. “The government have now sent some samples to three labs – but I have concerns over the providence, storage and chain-of-custody of those samples.”

And every week that passes without conclusive or reliable results pushes elephants – and humans – further into a zone of as yet-unknown danger. “What we really need is an independent team to be granted permission to enter, visit the site and intensively sample the whole area.” McCann adds. “For now we have to assume that every elephant in this region is at risk. Which is a terrible thought.”


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