Mystery has shrouded the deaths of more than 350 elephants across the northern Botswana region of the Okavango Delta.
The majestic creatures were first reported to be dying at the start of May, but by mid-June the figure had shot up to 169 after local conservationists discovered dozens of carcasses while flying over the region.
Just a few weeks on, that number has more than doubled, but nobody has so far provided a reason why.
Dr Niall McCann, of the UK-based charity National Park Rescue, described the mass deaths as “totally unprecedented” in circumstances unrelated to drought.
“At least 350 elephants have died – the scale of it is astonishing,” he said.
“Botswana is home to a third of Africa’s elephants and 10 per cent of those are in this region, so this could have a real impact on the global population.”