Beware of this Hippo!
No, this hippopotamus is not yawning. The open mouth signals: “I feel threatened. I am dangerous. Leave and let me alone, or I am getting really mad!”
Hippos are the third largest land mammals by weight behind the rhinoceros and the elephant. They are by nature very aggressive animals–they even fight against crocodiles. And the bulls fight each other in order to defend their territories (and the female hippos in them) or to enlarge their territories. Their big canine teeth serve as dangerous weapons in these fights.