The southern Africa country of Botswana is struggling to investigate the reasons for the mysterious deaths of over 350 elephants in the popular Okavango Delta nature reserve.
Authorities in Botswana, home to a third of Africa's declining elephant population, are struggling to send samples for analysis to international agencies to determine the cause of the deaths due to the lack of flights because of the COVID-19 lockdown in the region.
The sudden mass deaths of elephants, which scientists have called a conservation disaster, were first spotted during an aerial survey in early May.
The number of elephants died have since risen to over 350, most of them close to watering holes which have prompted suggestions that they might have died from poisoning.
But other scientists pointed out that if the water was indeed poisoned, it would have killed other animals as well.
Local experts have already ruled out anthrax as a possible cause, after about 100 elephants died of that disease last year.
"Some of the elephants we observed were moving about in circles in a kind of semi-conscious way before just falling down and perishing instantly," an unnamed pilot involved in aerial surveys told local media.
Scientists believe that there might be a neurological cause for the deaths because of this.
Authorities have also ruled out illegal poaching by ivory hunters, something that is a cause for concern in the region, as the carcasses had their tusks intact when they were removed by government officials.
Conservationists in neighbouring Namibia and South Africa, both of which also have sizeable elephant populations on the reserves bordering Botswana, have not noted any similar deaths.
Botswana has the world's largest elephant population, believed to be more than 130,000.