Just like a true Washingtonian, the banana slug is not deterred by our winter weather and rain. Their cousins, snails, retreat into their shells and hibernate throughout the cold and rain; but not the slug! Despite their relative vulnerability in lacking a shell, the slug continues to be active as long as the temperature remains above about 40 degrees Fahrenheit.

Slugs are fascinating creatures, full of bizarre surprises. Banana slugs have a long, ribbon-shaped “tongue” coated in tiny teeth that they use to shred their food. This mouth part, called a radula, can have up to 25,000 teeth! This astonishing mouth makes the bite of the great white shark, which contains only about 300 teeth, seem tame by comparison.

Banana slugs are often yellow and black, like a ripe banana. These colorations are affected by the slug’s diet, how much light it has been exposed to, and the age of the slug. Despite their tiny mouths full of vicious teeth, these animals are gentle giants that consume detritus (waste). Banana slugs will eat dead leaves, animal droppings, moss, and other organic material. When a slug is finished munching on detritus, that waste becomes a valuable part of the soil. Without decomposers like the banana slug, we would all be up to our ears in detritus!

Next time you see a banana slug crawling across the trail, take a moment to appreciate the unique biology of this fascinating animal.

Want to learn more?

 National Parks Creature Feature: The Banana Slug