Most gardeners hear the word slug and immediately have a negative thought about them being destroyers of their beautiful plants and I was guilty of this assumption too when I first heard banana slug. In most cases they are a nuisance, but the Pacific banana slug (Ariolimax columbianus), along with its other two relatives, the California banana slug (A. californicus), and the slender banana slug, (A. dolichophallus), have a different role in the environment. Banana slugs are detritivores (decomposers) and thrive on dead plant material, mushrooms, animal droppings, moss, and leaves. They recycle these materials and help with the dispersing of seeds and spores as well as take part in creating nitrogen rich fertilizer. The dead organic matter they consume supports decomposition on the forest floors and aids in nutrient cycles.
Banana slugs are primarily found in the Pacific Northwest, ranging from southern California up to Alaska and are home to moist, temperate, forest floors. They are the second largest slug in the world, reaching up to 10 inches (25 cm) in length and can live to be seven years old. They get their name because of their yellow coloring, resembling a banana, but can also take on dark spots or even become a little greenish. This is caused by a number of things such as their food consumption or the light or moisture levels they are exposed to and even the health of the slug. They have two sets of antennae that serve different purposes. The shorter set is used for sensory while the longer pair is used for sight.
One of banana slug’s unique characteristics is their slime. Banana slugs are prey to raccoons, garter snakes, ducks, and geese, but their slime serves as an anesthetic to predators causing their mouth to go numb if they dare take a bite. The slime isn’t toxic to humans and people have been known to lick them to test the theory of the numbing sensation. I personally haven’t tried it, but know people that can attest to its factuality. Another benefit of the slime is its ability to help them retain moisture. Banana slugs are mostly water and are prone to desiccation. The slime actually helps attract water and has the potential to absorb up to 100 times the slugs water weight. Slime also supports the banana slug’s mobility in navigating through the forest, gliding over dirt, leaves, and other debris.
Being new to the West Coast, I was unfamiliar with the banana slug’s positive influence on the forest floor and contribution to the soil. I thought they were a nuisance to the garden and plant life similar to other slugs, but in fact they are an important aspect of the ecosystem assisting in decomposition. The banana slugs still remain happy, innocent, inhabitants of the island. I was very excited the first time I spotted one and after I saw one, I must have seen 30 that day. Keep your eye out for these cute little guys on moist days and appreciate their positive impact in our beautiful forests. Hugs for slugs!