You can see the difference between a vole and a mouse by their physical appearance. Voles have a rounder body with a shorter tail than mice. They also tend to be browner in coloration, while mice are typically gray or white. In terms of size, voles are typically smaller than mice. Another difference between these two animals is that voles create runways through grassy areas, while mice do not. You can also tell the difference in their behavior. Voles are more likely to be active during the day, while mice are more likely to be active at night.