Sources
BBC Wildlife Magazine, Dec 2009; http://animals.sandiegozoo.org/ animals/hippo; http://indianapublicmedia.org/amomentofscience/ do-hippos-swim/; http://animals.Nationalgeographic.Com/animals/ mammals/hippopotamus/
BBC Wildlife Magazine, Dec 2009; http://animals.sandiegozoo.org/ animals/hippo; http://indianapublicmedia.org/amomentofscience/ do-hippos-swim/; http://animals.Nationalgeographic.Com/animals/ mammals/hippopotamus/