Thank you for all your answer.
I only regret that most of you let their heart speak rather than really explain their choice.
I just want to specify the question is not wich do you prefer beetween these animals, but which do you think is the stronger and will gain the victory during a fight.
By example, the hippopotamus has big jaws but the elephant has defenses ... so, can you imagin what will happen during a fight beetween them ?

(sorry if my english is not verry comprehensible, but I'm german ..)