The Banana Slug, native to the Northwest, can grow to a length of 8 inches, with a few giants reaching 10 inches and weights of a quarter of a pound. Banana Slugs are usually bright yellow with a shape somewhat resembling a banana; they may also be green, black, brown, or white, or have spots of these colors.

Slugs use two pairs of tentacles to sense their environment. The larger, upper pair, termed "eye stalks," is used to detect light or movement. The second, lower pair is used to detect chemicals.

Dehydration is a major problem for slugs. To prevent their bodies from drying out, slugs they secrete a protective layer of mucus, and insulate themselves with a layer of soil and leaves. They remain inactive in this state until the environment is moist again.

Banana Slugs are detritivores. They process leaves, animal droppings, and dead plant material, and then recycle them into soil. They seem to have a fondness for mushrooms, spreading seeds and spores when they eat. Slugs move relatively slowly since they have only one muscular foot. They are sometimes eaten by raccoons, garter snakes, ducks, geese, salamanders, shrews and moles.

Salt is harmful to all slugs. Through osmosis, water diffuses to the surface of the skin to dilute the salt, causing the slug to dehydrate.

For many years, the Banana Slug served as the unofficial mascot for the University of California at Santa Cruz campus because it represented many of the strongest elements of the campus: contemplation, flexibility, non-aggressiveness and, perhaps above all, an iconoclastic challenge toward the status quo. In addition, the Banana Slug is indigenous to the region and shares a symbiotic relationship with the California Redwood that populates the scenic campus. In 1986, students demanded that the Banana Slug be blessed with official mascot status.