A while ago, an Earth Touch crew was preparing to embark on a pretty crazy mission: diving in the Okavango Delta to film Nile crocodiles in their underwater lairs. Before their departure, there was one potential animal encounter that caused a few sleepless nights ... and it wasn't of the reptilian variety. Instead, the surprising culprit was the hippopotamus. They might look harmlessly rotund and sluggish, but gentle giants they are not. Hippos are infamously aggressive and unpredictable ... and that, coupled with an impressive running speed (a hippo probably rivals Usain Bolt's 28mph) and a mouthful of enormous canines and incisors, makes them one of Africa's most dangerous animals. So when hippos see red ... Well, just watch.