They may measure up to four inches in length and are yellowish-brown to black in color. Some may be mottled or streaked with darker markings.
All species leave a telltale, silver-colored, slime trail wherever they travel.
These trails can be seen on foundation walls, basement floors, roads, walkways and plant leaves. Slugs require a great deal of moisture and prefer dark areas. They are commonly found associated with moist, dark places such as under boards, logs, stones, decaying organic material, mulch, trash, flower pots and in crevices, especially in shaded locations. Slugs feed mostly at night and hide during the day to avoid the drying effects of sunlight. They feed on many kinds of plants, chewing ragged holes in the leaves, especially those that lie close to the ground.