By Gusjer - Hippo at dawn. Chobe National Park, CC BY 2.0,  https://commons.wikimedia.org/w/index.php?curid=22523580 In Ancient Greek Hippopotamus means "River Horse". Hippos can run faster than humans. A Hippopotamus is considered as the most dangerous animal , In Africa it is known to kill more people annually than lions and tiger. When hippos are upset, their sweat turns