I think I could sit and watch wild Hippopotamus all day (my wife, however, would rather spend her time watching other animals as hippo behavior does not impress her). They are super interesting to watch and photograph. Hippos are fairly dangerous animals and are typically nocturnal, but they are still surprisingly active during the day. It is fascinating to watch the social structure of a group/raft of hippos. They can be extremely aggressive to each other as they fight for position in a small space of an otherwise open river area.
I took this photograph along the Grumeti River in the Serengeti National Park, Tanzania.