Hundreds of elephants have been found dead in Botswana's Okavango Delta. Poaching has been ruled out as the tusks had not been removed. Wildlife specialists have described the die-off as a "conservation disaster".
Botswana in southern Africa has the world's largest elephant population, estimated to be around 130,000.
"We have had a report of 356 dead elephants in the area north of the Okavango Delta and we have confirmed 275 so far," Cyril Taolo, the acting director of the department of Wildlife and National Parks, told the French news agency AFP.
He said the cause of the deaths has yet to be established but anthrax has already been ruled out. Anthrax killed at least 100 elephants in Botswana last year.
"We do not suspect poaching since the animals were found with tusks," he said.
Cyanide poisoning has also been discounted by experts, since elephants are the only species affected. "If it was cyanide used by poachers, you would expect to see other deaths," said Dr Niall McCann of the UK-based charity National Park Rescue.
More than 350 elephants drop dead in mysterious mass 'die off' clustered around water holes in Botswana's Okavango Delta
The carcasses are yet to be tested for pathogens or poison despite the first dying in EARLY MAY. https://t.co/tiSGyisEpB pic.twitter.com/xgFCEZ6nIP
- animals_innocent_creatures (@AnimalsInnocent) July 1, 2020
Samples have been collected and sent to South Africa, Zimbabwe and Canada for testing.
Results are likely to take weeks to process.
Similar deaths were first reported in May when authorities found 12 elephant carcasses in just a week near two villages in the northwest of the country.
All age-groups affected
The latest discoveries were flagged by the wildlife conservation charity, Elephants Without Borders (EWB).
EWB suspects the elephants have been dying in the area for about three months.
According to the report dated 19 June 2020, "Seventy percent of elephant carcasses were considered recent, having died about a month ago, and 30 percent of the carcasses appeared fresh, ranging from one day to two weeks old."
There is evidence that elephants of all ages and both sexes appear to be dying, says the report.
Several living elephants have been described as weak, lethargic and emaciated, with some showing signs of disorientation, difficulty in walking or limping, EWB said.
"One elephant was observed walking in circles, unable to change direction although being encouraged by other herd members," said the report.
There have been no reports of elephant deaths in any neighbouring countries.