Hippopotamus\nAlthough hippopotamuses cannot swim particularly well, they spend nearly all day in the water.\n\nAlthough hippopotamuses cannot swim particularly well, they spend nearly all day in the water. They cannot simply drift along, because they're just too heavy. If they wish to cross a river, they allow themselves to sink to the bottom and walk along the river bed to the other shore.\n\nFun fact\nHippopotamuses can hold their breath underwater for up to 30 minutes.