The deaths of more than 300 elephants in Botswana this year were caused by toxins produced by cyanobacteria in water, but there were still many unanswered questions, wildlife officials have been quoted by Reuters news agency as saying. The deaths in the Okavango Delta sparked widespread alarm and left conservationists and veterinary surgeons baffled, especially as there was no sign of other animals dying at the same time. Reuters quoted Mmadi Reuben, a senior veterinary officer in Botswana’s Department of Wildlife and National Parks, as saying that latest tests had “detected cyanobacterial neurotoxins to be the cause of death”.