The Nile crocodile has teeth arranged in a straight line, transparent eyelids, ears on top of its head, and eyes positioned high on its skull. It lives in rivers, marshes, swamps, and water holes in warm parts of Africa and is known as one of the only man-eating species. While good parents, Nile crocodiles are always grumpy and kill other animals. The phrase "to shed crocodile tears" comes from crocodiles shedding tears to remove salt from their eyes.