A hippopotamus has a very similar digestive system to other hooved mammals. They have lips that are about 70 centimeters long that helps clip grass and other vegetation off and grind it up into a pulp so it is easier to be swallowed. Since they do not regurgitate this pulp their system is ineective compared to other grazers. The food then travels down the esophogus and is digested in the stomach. Then ater digestion, the waste is excreted.