Slug is a kind of snail that usually has no shell. Some slugs possess a small, flat shell on or under the skin. For protection, they secrete a thin layer of bad-tasting slime. Slugs have both male and female sex organs. They usually mate in pairs but can reproduce without mating.
There are two kinds of slugs—land slugs and sea slugs. Land slugs may have white, gray, yellow, or brown bodies. They range in size from 1/4 inch (0.6 centimeter) to about 4 inches (10 centimeters) long. Most have tentacles (feelers) with eyes at the tips. Land slugs can become garden pests because they feed on plants. Some species eat fungi, insects, earthworms, animal waste, or other slugs. Land slugs will dry out in sunlight, and they usually spend the day hiding underground or beneath damp objects. Sea slugs live in the sea and often have colorful bodies. They eat seaweed or marine animals, such as sponges.
