Hippopotamus (Hippopotamus amphibius), yawning in Retina hippo pool, Serengeti National Park, Tanzania, Africa

africa african amphibius animal animals area areas artiodactyla conservation day daylight daytime during even even toed exterior exteriors fauna hippo hippo hippopotami hippopotamus hippopotamuses hippos kingdom mammal mammalia mammalian mammalians mammals national national natural nature nobody outdoor park park parks photo photos pool preserve preserves reserve reserves retina sanctuaries sanctuary serengeti shot shots tanzania tetrapod tired tiredness toed toed ungulate ungulates vertebrata vertebrate vertebrates wild wildlife world yawn yawning yawns