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  • José H. Leal

Blue Dragons on Texas Beaches

Last weekend the national media was abuzz with the news that “venomous blue dragons” that “look like mini-Pokémons” were washing ashore along Texas beaches, including those on Padre Island and near Corpus Christi. Blue Dragons, also known as Blue Glaucus (Glaucus atlanticus), are inch-long, blue and white sea slugs that spend their entire lives in open water, floating upside-down just under the water surface. They are part of the neuston ecosystem, the mysterious ecosystem at the ocean’s surface that includes, among other organisms, the Purple Snails (Janthina species), Sargassum seaweeds, By-the-Wind Sailor (Velella species), and the Portuguese Man-o-War, Physalia physalis. As a result of their floating/drifting life habits, neustonic organisms are carried haphazardly by winds and currents and, depending on season and location, may occasionally wash ashore.


Blue Dragon, Glaucus atlanticus. Photo Adobe Stock.

Blue Dragons feed on Portuguese Man-o-War (a relative of jellyfish), neutralizing their nematocysts (stinging cells), storing them in the extremities of their finger-like cerata, and eventually re-using them for their own protection. They can be harmful to humans when touched, as the recycled Man-o-War nematocysts pack quite the punch when it comes to toxicity and ability to inflict pain. Unlike at least one media outlet proclaimed, Blue Dragons are not “invading” Texas beaches, as their presence in those locations is temporary and ends up in death for the little sea slugs. Media hype notwithstanding, it is always great to read about mollusks in the news!


The Blue Dragon's favorite food, Portuguese Man-o-War, Physalia physalis. Photo by Bengt Nyman, Wikipedia CC BY 2.0.