Cyanobacteria are commonly found in water, but not all of them produce toxins. Scientists fear that climate change will cause bacteria to produce more toxins as the water temperature rises and conditions become more favorable for bacteria to grow.
Botswana is home to 130,000 African elephants – more than any other country on the continent. Last year, the country dropped an elephant hunting ban it had in place since 2014, sparking international outcry.
Some conservationists had suspected poachers of killing the elephants, which died in May.
“I don’t think anyone can ever say never, but in this case the available evidence shows it was a natural occurrence,” he said at a press conference.
Taolo said additional clues on the ground, including that the dead elephants had all found their tusks intact, reinforced the government’s conclusions that the deaths were naturally caused. “We have ruled out poaching,” he said.
But skeptical conservationists are demanding that the full results of the government investigation be released.
“If it is in water points or if it was in water points, why are there only elephants that have been affected? Keith Lindsay, a conservation biologist, whose research focuses on elephants, told CNN.
Lindsay says the evidence presented so far is not conclusive enough to rule out human involvement.
“The only thing elephants do than other species is that they go and get crops from farmers’ fields,” Lindsay said.
“If farmers spread poison, elephants of all ages would catch this toxin and then return to their water points. At least, if not more likely, these cyanobacteria cause death. ”
The Okavango Delta, where the carcasses were found, is home to 10% of the country’s elephants. The species is classified as vulnerable on the Red List of the International Union for the Conservation of Nature (IUCN).
Brent Swails reported from Johannesburg. Zamira Rahim wrote in London.