P. maniculatus is a deceptively cute animal, with big eyes and big ears. Its head and body are normally about 2 - 3 inches long, and its tail adds another 2 - 3 inches in length. Depending on its age, you may see it in a variety of colors, from gray, to reddish brown. The underbelly is always white, and the tail has sharply defined white sides. The deer mouse is found almost everywhere in North America. Though this mouse prefers woodlands, it also turns up in desert areas.