Identify rodent droppings based on comparisons of size, color and other physical attributes. While similar, droppings of rats, mice and squirrels are all slightly different from each other.
If the rodent droppings look like small grains of brown rice, they are likely mouse droppings. These tend to be the smallest rodent droppings as compared to rats and squirrels. The droppings are usually thin and at least one end is pointed. Rat droppings, on the other hand, are usually oblong and might be slightly wider near the middle. They are usually dark in color and have a moist and shiny appearance. They can get lighter and dryer as they age. Roof rats might have droppings that are curved in shape and have a pointed end.
Squirrel droppings are similar in size to mouse droppings, though slightly bigger. They are usually smaller than rat droppings, at about 3/8-inch to 1/2-inch in size. They are usually the size of a raisin with round ends and an oblong shape. These are sometimes smaller in length, yet fatter than the rat droppings. They are dark in color as well.
For all these droppings, pay attention to the color. If it is a lighter color, they are old, and the rodents might not still be in the house.