They are smaller and appear like dark rice grains and have a tapered look towards the end. They are approximately a quarter of an inch as compared to the rat droppings, which are 1/2 of an inch wide and larger than those of the mice. When comparing mouse poop vs cockroach poop, it is important to note that the big cockroaches’ poops have ridges along with the droppings while the mouse droppings do not have these ridges. So, when you see pests poop in your house, but you are not sure if they are for mice, compare them with mouse droppings images to see if they match.