No definitive answers have yet been found for the mass die-off of elephants in Botswana since May this year.
Early research results have suggested, however, that the deaths could be attributed to a naturally occurring toxin.
This emerged in a recent investigative paper published in the African Journal for Wildlife Research by a team of researchers from South Africa and Pakistan, who aimed to gain an understanding of the cause of death of more than 350 elephants in that country.
Dr Gerhard Verdoorn, CropLife SA’s operations and stewardship manager, told Farmer’s Weekly it was highly likely that the deaths were caused by mycotoxins from infected water sources.
The mycotoxins severely affected the neurological system, resulting in rapid death. This could explain why some of the elephants collapsed mid-stride and caved in on their knees.
Carcasses were first found in the Okavango Panhandle region, and blood samples had since been tested by scientists in Zimbabwe, the US, and at the University of Pretoria’s Faculty of Veterinary Science in South Africa.
In the paper, the team observed that the death of the elephants in Botswana “was indiscriminate in line with their age and gender, while death for some was sudden, as elephants were found collapsed forward onto their chests, tusks in the ground, rather than on their sides.
Viral and bacterial agents that could precipitate species-specific mortalities on this scale, potential environmental sources of poisoning, and the samples and tests that would assist in excluding/confirming these candidate causes were considered”.
Botswana’s elephant population of 130 000 had been stable for the past 25 years.
Considering that yearly mortalities of between 3 000 and 4 000 individuals should be associated with this stable population size, the writers argued that the loss of some 400 elephants was unlikely to negatively impact the broader elephant population.
Their concern was, however, that the current wave of elephant mortalities would continue and spread to other areas.
A second consideration was that a similar mass mortality event would affect small and isolated elephant populations, which would not be able to withstand the loss of so many individuals, the paper said.