Some bodies were found piled up around the watercourse, while others died “falling straight in the face”, said Niall McCann, director of protection at the National Rescue Park in Great Britain.
The live elephants seen nearby looked physically weak, and one was walking in circles, unable to change direction, observers said. Other species in the area do not appear to have affected what struck the elephants.
The Botswana government is testing samples of dead elephants, but the cause of death has yet to be determined.
An unusual number of elephant carcasses was first recorded in early May, McCann said.
“It’s awful – we need to know what the hell is going on,” he said, adding that he can’t remember another time when so many elephants died from a mysterious cause.
“800 of them lie around like a magnet for criminals,” he added.
McCann said there were a number of possibilities for what could have caused the death, including a specific elephant parasite – or even Covid-19.
“What I would like to emphasize is that it could be a public health crisis,” he said.
Whatever the cause, McCann said it’s important to get to the bottom of it because the loss of elephants ’lives is already“ significant globally ”.