We all know barnacles as those hard, white bumps found all over beach rocks. Live barnacles have a round calcareous outer shell and internal plates that form a narrow slit. If you touch these plates gently, they’ll move as the creature inside closes them for protection.
Why they’re cool: This stationary animal, related to crabs and lobsters, may not seem exciting. However, when underwater, barnacles extend feather-like legs to catch plankton.
Nicole J. Persun is an award-winning novelist, writing instructor and the former digital content producer for ParentMap. Read her latest books under the pen name Jennifer Gold.