Why are elephants dying? The race to solve the mystery of mass die-offs

Hundreds of animals perished in Botswana and new deaths are reported in Zimbabwe - now scientists are trying to find the cause

Earlier this year, more than 350 elephants mysteriously died in the Okavango delta in Botswana. Individuals of all ages and both sexes were affected, with many walking in circles before dying suddenly, collapsing on their faces. The mass die-off in May and June was described as a conservation disaster".

Three months later, most surviving elephants have fled. Last week a plane flew over the Okavango Panhandle, an area in the north-west of the delta where most of the deaths occurred, and eight elephants were spotted, when normally you would see hundreds, says Dr Niall McCann, director of conservation at UK-based charity National Park Rescue. It is understandable, I'm sure you or I would flee if all our friends and relatives were dying, and that's what the elephants appear to have done."