Both the rat and mouse belong to the same family of species known as Rodentia, which means that  they share similar qualities. However, rats tend to be slightly larger with longer and scaly tales. Mice, however, have a smaller structure with shorter tails that are slightly more hairy. These main aspects must be considered when creating a rat drawing, as they all work together to contextualize the rat. When drawing a rat, remember that it has quite a blunt snout, which is slightly less pointy than that of a mouse. A good suggestion is to look at some reference images when creating your rat drawing.