Officials in Botswana are investigating the mysterious deaths of hundreds of elephants in the Okavango Delta area of the southern African nation within the past three months.
The Ministry of Environment, Natural Resources, Conservation and Tourism said Thursday that it had verified 275 carcasses of the 356 deaths that have been reported since early May.
Samples have been sent to three laboratories in Zimbabwe, South Africa and Canada for analysis. The environmental ministry said that ongoing investigations have so far “revealed no evidence of poaching.”
Natural anthrax poisoning, which killed at least 100 elephants in Botswana last year, has reportedly been ruled out as a cause of death for the elephants investigated this year.
However, Niall McCann, of the U.K.-based charity National Park Rescue, told The Guardian that experts have not been able to officially rule out poisoning or disease.
“This is a mass die-off on a level that hasn’t been seen in a very, very long time. Outside of drought, I don’t know of a die-off that has been this significant,” he said.
McCann said that sightings of other elephants walking in circles points to something potentially attacking their neurological systems.
“If you look at the carcasses, some of them have fallen straight on their face, indicating they died very quickly. Others are obviously dying more slowly, like the ones that are wandering around. So it’s very difficult to say what this toxin is,” said McCann.
The dead elephants have been all ages and both sexes, with many clustered around watering holes, according to The Guardian.
Botswana, a country home to nearly one-third of the entire African elephant population, last year lifted its years-long ban on elephant hunting.
Local communities in the nation have been advised to not tamper with the dead elephant’s tusks. While poaching has not been entirely ruled out, it has reportedly been deemed unlikely because the tusks have not been removed from the carcasses.
The Guardian noted that cyanide poisoning, a method often used by poachers in Zimbabwe, could be a possible explanation but scavenging animals do not appear to be dying near the bodies.
The COVID-19 pandemic has also been mentioned as a possible cause but is also considered unlikely, according to the outlet.
However, McCann told The Guardian that testing needs to be ramped up since there is “no precedent for this being a natural phenomenon.”