今年五月及六月期間，有三百多隻非洲象離奇死亡，因頭上還有象牙，所以相信並非偷獵者所致。研究發現牠們的死因很大機會與含毒素的藍菌有關，氣候變化令藍菌大量生長。因為七成死亡的象都橫屍在水源附近，相信牠們是在水源洗澡及飲用這些水後死亡。

Over 300 African elephants mysteriously died in May and June of this year; they were not killed by poachers as heir tucks were not removed. researchers found out their death could be due to cyanobacteria toxins from waterholes. During the rainy season, there were harmful algal blooms triggered by climate change in the waterholes where the elephants bath and drink, and 70% of these elephants were found dead near these waterholes that produce cyanobacteria

https://www.natureworldnews.com/articles/44455/20200921/botswana-mystery-mass-elephant-die-solved.htm