These soft-bodied mollusks are closely related to sea slugs!
“Nudibranch” means “naked gills,” referring to the fact that they carry their gills on their back. Here’s a closeup of nudibranch gills:
Many nudibranch species are spectacularly colorful, from the Spanish shawl nudibranch, found in Channel Islands National Marine Sanctuary:
to the opalescent nudibranch of Cordell Bank National Marine Sanctuary, which preys on hydroids and anemones. During digestion, the hydroid and anemone stinging cells actually travel into the nudibranch’s colorful appendages and can be used against the nudibranch’s own predators!
Nudibranchs are found all over the world’s ocean and in many of your national marine sanctuaries.
What’s your favorite kind of nudibranch?
Did someone say Sea Slug Day?