Slug photo courtesy of Mirka Hokkenen-Kim

I know, I know… a slug isn’t an arthropod, which means it’s definitely not an insect. But it is still an incredible animal that can be found here in the Pacific Northwest. Slugs are in Class Gastropoda and related to snails, clams, and other mollusks. They have four prominent tentacles on their heads. The upper pair, called eyestalks, act like periscopes so that this low-riding slug can see a bit further. The lower, shorter pair of tentacles is used for chemo-reception– to detect chemicals or pheromones in the environment. They have really cool rasping mouthparts (imagine little shark’s teeth that point backwards in a circular row!). They use these to eat and can be a real pain for gardeners.

The first thing that comes to mind when people think about slugs is slime. They excrete thick mucus that coats their entire body. This helps to protect them from dehydration. It also contains special pheromones so slugs can find mates!

This slug was found around Puget Sound in Washington. It was about six inches long!

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