Creature Feature: Blue Dragon Nudibranch (Glaucus Atlanticus)

Blue Dragon Nudi long

With the holidays right around the corner, ’tis the season for bright lights and colorful decorations.  In MSI’s true, creature-crazy fashion, we want to spread some of that cheer with a seriously cool, vibrant creature that will trump any string of tinsel.  The Blue Dragon Nudibranch (Glaucus Atlanticus), isn’t very big, but its look makes a huge statement!

Nudibranchs are soft-bodied mollusks that shed their shell after their larval stage. The Blue Dragon has striking coloration ranging from lavender to dark purple to blue and to light golden brown. You can see them drifting around Australia near the surface of the water, sometimes flipping and turning, but mostly just floating. Gas bubbles in their stomachs help them stay buoyant in the water. Nudibranchs (affectionately referred to as “nudies” by most MSI staffers) have two rhinophores, which are located on their head and are feathery shaped to optimize the surface area. Rhinophores are important for a nudibranch because they help them sense (primarily smell and taste) to find food and mate.

Though their color scheme is impressive, Karen Peluso, MSI’s Ship Program Manager, is far more interested in what Blue Dragon Nudibranchs eat.  They munch away on Portuguese Man-of-Wars, creatures that most humans would swim away from as fast as they could whilst screaming for their mommies.  Never heard of a Portuguese Man-of-War? Many people consider them to be types of sea jellies and though they are a jelly relative, they are in fact siphonophores. This means they are a collection of hydroids and polyps, the length of which can reach over 100ft long.  Like jellies, these hydroids and polyps posses nematocysts (remember the stinging cells?) that can be immensely painful for humans who are stung. By eating Portuguese Man-of-Wars, Blue Dragon Nudibranchs will store the nematocysts in their own bodies so that they too are toxic to the touch. An amazing adaptation!


Edited by KC O’Shea

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