Sea Slug

ocean · mollusks · no-shell snails

Lost their shells. Sea slugs are actually snails that evolved to either completely lose their shells or shrink them down so much you can barely see them. Over millions of years, they didn't need their shells anymore to survive in the ocean.

Come in wild colors. Many sea slugs are incredibly bright and colorful, with patterns and frills that look like living artwork. These colors often warn other animals that they might be poisonous, so don't mess with them!

Still gastropods. Sea slugs belong to a group called gastropods, which is the same family as regular garden snails and sea snails. Even though they lost their shells, they're still closely related to their shell-wearing cousins.

Hard to define. Scientists use the term 'sea slug' for lots of different ocean creatures that look similar but aren't always related. It's more of a nickname than a strict scientific name for one specific animal.

Marine invertebrates. Sea slugs are invertebrates, meaning they have no backbone or skeleton inside their bodies. Instead, they have soft, squishy bodies that let them squeeze into tiny cracks and crevices on the ocean floor.