When stretched out, the average Iowa garden slug will be up to 1 inch in length. Slugs are animals on a very large branch of the Animal Kingdom family tree called Mollusca. The best known molluscs are the clams and oysters, squids and octopuses, and snails and slugs. A majority of gastropods live in the ocean and include many of the decorative seashells found along the beach. The large fleshy foot that protrudes from the shell of a snail or oyster and on which they crawl, also contains the mouth opening.
Gastropods rasp their food.
Slugs feed at night except if the day is rainy, cloudy or foggy. Otherwise they remain out of sight during the daytime by hiding under mulch, leaf litter or damp debris on the ground. Slugs feed on a variety of plant matter, living or dead and decaying. Damage generally appears as large, irregular holes of missing plant tissue. During mating, two individuals join to accomplish mutual fertilization.