Wood mice will gather food stores of berries and seeds in the autumn, which they keep in underground burrows or sometimes in old birds' nests. Mouse vs Rat Differences Between Rats and Mice Mice. The wood mouse is sometimes known as the long-tailed field mouse and is widespread; it is probably most common in woodland, rough grassland and gardens. A regular adult rat will weigh between a half and one pound, whereas a mouse is more like half an ounce. The body length of a rat is typically nine to 11 inches, whereas a mouse's body is just three or four inches. Size: House mice measure 12 to 20 cm in length, including the tail, and weigh 12 to 30 grams. While a rat is either medium-sized or large, a mouse is relatively smaller in size. ; Color: They may be white, brown or grey in color. It is mostly nocturnal and an agile climber. Rats are also over ten times heavier. Both mouse and rat have a pointed snout, though. However, if you know what to look for, you might be able to tell whether it’s a rat or a mouse as they scurry through your home. Weighing around half an ounce, a mouse is smaller, with a pointed nose, large ears and fur. ; Head: Their snouts are triangular and feature long whiskers. ; Tails: Mice have large, floppy ears and long, thin, hairy tails. About. Still, as compared to that of a mouse, the muzzle of a rat …