Banana Slugs

BC’s coastal rainforests are famously home to giant organisms. But beyond the big trees, these forests also produce giant slugs! The banana slug is the second largest slug on earth, being able to reach 9 inches (23 cm) in length. These charismatic, often bright yellow creatures are signature members of the rainforest community.

Banana slugs are enthusiastic omnivores that feed on plants, detritus, and carrion, but they seem to have a special fondness for mushrooms. Feeding is done through their specialized rasp-like tongue called a radula. This tongue is equipped with over 20,000 ‘teeth’ that the slugs use to shred their food. If mushrooms have nightmares, they’re probably of tooth-studded tongues!

Another secret to the banana slug’s success is its slime, which is hydrophilic and able to absorb 100 times its weight in water, keeping the slug moist. The slime also provides the animal with locomotion, adhesion, and protection.

The slime is neither solid nor liquid, but a strange substance known as a liquid crystal, in which the molecules are fluid but structured. The slime is, paradoxically, both an adhesive (allowing the slug to stick to things) and a lubricant, allowing the slug to slide without resistance. Thanks to slime, a slug can even travel across a razor blade without injury.

Finally, the slime provides protection, as it contains a paralytic toxin. Any human foolish to give a slug a big lick will find their tongue and lips go numb. Clever raccoons will roll the slugs in dirt in order to bind up and remove the slime before these little bandits dine on banana-escargot.