House mice (Mus musculus) are smaller than rats (2-3.5″ with 3-4″ tail) but similar in appearance. Young rats are sometimes mistaken for mice. House mice are almost never seen outdoors.
House mice will readily infest homes and other occupied, man-made structures. Because they are very small, they are difficult to keep out of structures and may not be discovered right away. They may be active during the day or only at night.
House mouse droppings are pointed and approximately 1/4″ in length.