Ippopotamo che sbadiglia in un tranquillo fiume africano illuminato dal sole

create a photorealistic picture of a hippopotamus standing partially submerged in a wide, calm African river, its enormous mouth opened wide, clearly showing its large teeth and powerful jaws. Warm natural sunlight, lush green vegetation along the riverbanks, realistic water reflections and splashes, dramatic wildlife-photography composition, detailed skin texture, cinematic lighting, high resolution, natural colors.