Evergreen Natural History Database

Common name(s): Banana slug

Size:
Ariolimax columbianus is the second largest land slug in the world. Adults range from 15-20cm in length. Some have been recorded at 25.4 cm!

Range:
Southeast Alaska is the northern most reach and as far south as Salinas Valley in Central California. Found only on the western side of the Cascade and Sierra Nevada ranges.

Habitat:
Damp forests are the habitat of preference. Rarely found in cosmopolitan areas.

Identification:
The banana slug has a wide color range. Anywhere from white to black and all forms of yellows and browns in between. The most common color is a variation of yellow. Sometimes found with spots or blotches. If unidentifiable by its coloring, massive size or its preferred habitat, there is a fourth option. At the tail end of the slug is a small indent with a mucous plug called the caudal pore.

Life History:
Banana slugs love to eat. They usually feed in the day during spring and fall. Mushrooms are the banana slug's favorite food. But they eat almost anything. They will munch on both living and decaying plants, bulbs, lichen, algae, fungi, animal droppings and animal carcasses. It is thought that their habit of cleaning up the forest floor helps disperse seeds throughout the forest. Not to worry about your garden. If you find a slug there it is probably there by accident. Banana slugs prefer the dense forest to your garden and rarely eat the vegetation growing there.

Natural History:
Banana slugs are know hosts for parasites. Tiny mites live on the outside of the slug's body. One type of mite, the Riccardoella limacum, is found only on slugs. They are also intermediate hosts to internal parasites. Flukes, round worms, and tapeworms are passed on to other animals that ingest banana slugs.

Predators:
The banana slug has a large assortment of predators. There have been accounts of garter snake, fox, salamander, newt, beetle, crow, duck, millipede, porcupine, raccoon and other species of slug eating a banana slug for lunch.

Links: Slug Story

Suggested Reading:

Gordon,D.G. (1994). Field Guide to the Slug. Sasquatch Books, Seattle, 48 pages.

Harper, Alice Bryant(1988). The Banana Slug. Bay Leaves Press, Aptos California, 32 pages.

Last updated Tuesday, September 05, 2006, by Lisa Ferrier