head of a hippopotamus hippopotamus amphibus semi-submerged in water

africa amniote amphibius amusing animal artiodactyl beautiful biology closeup common conservation creature cute dangerous ecology endangered endothermic eukaryotic evolution exotic eyes fauna head hippo hippopotami hippopotamidae hippopotamus kenya lake large mammal mangrove national nature organism outdoor park river safari semiaquatic semisubmerged species swamp tanzania vertebrate water wild wilderness wildlife zoo zoology