The Glaucus Atlanticus

Glaucus Atlanticus Doodlewash Blue sea swallow, blue angel, blue glaucus, blue dragon, blue sea slug and blue ocean slug watercolor illustration

Meet the Glaucus atlanticus, a tiny sea slug that’s only 3 cm long, floating on the surface of an ocean near you. Like many of these uncommon creatures, this one has a lot of names which include a sea swallow, blue angel, blue glaucus, blue dragon, blue sea slug and blue ocean slug. Despite its colorful appearance, this isn’t a creature you’d like to come across as it’s loaded with poison due to its unique diet. It feeds on the venomous Portuguese man o’ war, a creature often mistaken for a jellyfish which also goes by the unsettling name of the “floating terror.”

This small invertebrate eats hydrozoans from the man o’ war, which are fatal to humans, but easily consumed by the Glaucus atlanticus. It has hard disks inside its body that act as protective barriers, secreting a special mucus. After enjoying a meal, the Glaucus atlanticus stores the poison inside its body for the future in order to defend itself. Some scientists think that if this little sea slug has a voracious appetite, it can end up becoming far more dangerous than even the Portuguese man o’ war.

The Glaucus Atlanticus is neither male nor female, but a hermaphrodite with both reproductive organs. After mating, each slug produces eggs, which they lay on driftwood, or on the skeletal remains of their enemies. When food is in short supply, things get a little crazy. When one slug meets another in the neighborhood, rather than wave hello, they’ll simply begin to eat the other head first. Yep, turns out this little pint-sized blue dragon is also a poison-sucking cannibal. Too bad, really, as they are such a lovely shade of blue.

About the Doodlewash

M. Graham watercolors: Cobalt Blue, Cobalt Teal, Ultramarine Blue, and Neutral Tint. Lamy Safari Al Star pen with Platinum Carbon blue ink in a 5″ x 8″ 140 lb. (300 gsm) Pentalic Aqua Journal


Recommend0 recommendationsPublished in By Charlie
  1. Carol 7 years ago

    It really is a beautiful creature, but yikes – deadly! Your painting makes it look almost like a lovely glass collectible to be put on display, which is the only way I’d want to meet up with one of these. Very nice, Charlie 👍🏻

    • Author

      Thanks so much Carol!! 😃💕 Yeah…they’re so weirdly pretty and I no idea they liked to eat poison for dinner. I’ll be keeping my distance as well!! Hehe

  2. Teri C 7 years ago

    Gorgeous colors on the deadly creature. Admire from afar, very far.

    • Author

      Thanks Teri!! 😃💕 Yeah…best to stay away from this one. Though there were several posts about people wanting to keep them as pets. Yikes!

  3. artandmoondreams 7 years ago

    Lovely painting of a lovely, if not painfully so, creature. Have never seen one here, but will definitely keep my eyes open in case one happens by.

    • Author

      Thanks Haunani! 💕😃 they are so interesting and beautiful, but yeah…not a creature that you’d want to pet! Hehe

  4. Jodi 7 years ago

    I was loving it until the last line! LOL! Great doodlewash and info!

    • Author

      Thanks Jodi! 😃💕Haha! What? You have something against poison-sucking cannibals? Yeah… not a cute little addition to an aquarium with this guy/gal. Hehe

  5. The Leaf Diary 7 years ago

    pretty creature!

  6. Teresa Robeson 7 years ago

    As freaky scary as this thing is, you managed to make it so magnificent that I’m a little in love with it! 😀 <3

  7. Jill Kuhn 7 years ago

    Love it’s colors but would hate to meet up with one! Not sure I’d see it at that small size… Another reason to NOT go swimming in the ocean which is fine with me! Hehe! 😜💙🎨

    • Author

      Thanks Jill!! 😃💙 hehe…Yeah…looking up these creatures like this has sort of scared me from ever hopping in the water! Lol But they’re so pretty and I really do love snorkeling! 😊

      • Jill Kuhn 7 years ago

        I do like snorkeling too, Charlie! But then I got caught in a riptide on Maui… It was really scary! So unless it is a protected reef, I’m staying on shore! 😬🐠 Where do YOU like to snorkel?! 😄🛳

        • Author

          I actually only snorkeled for a week at various beaches in Vieques, Puerto Rico. It was amazing, but did end up getting a rash from some kind of seaweed or something. Not pleasant! 😊hehe… but if do it again!

          • Jill Kuhn 7 years ago

            The colors of fish is what I found AMAZING! How about you?! 😃

          • Author

            The same!! … I just LOVE color!! ❤️💚💙💜hehe

  8. Yikes, scary creature, I don’t think we get them in our waters, at least I hope not. Great colours though.

    • Author

      Thanks Rebecca! 😃💕 Yeah…the blue is so pretty on this creature. But not one I’d want to meet during a swim!!

  9. Jessica Seacrest 7 years ago

    Beautiful blue! It’s so fun having you as a tour guide :).

  10. Sharon Mann 7 years ago

    Yikes, beautiful but deadly. I love the blue tones, Charlie. Very nicely rendered.

    • Author

      Thanks Sharon!! 😃💕 Yeah…best viewed from a distance…but they’re super tiny so best viewed from photos. Hehe…even safer that way! 😉

  11. Kari 7 years ago

    This is the most beautiful slug I’ve ever seen! That blue has become my favorite blue! Maybe deadly bit so pretty to look at! I’m hoping to do some art this week since it’s my spring break!! Woohoo!! Haha.. ❤️😜❤️

    • Author

      Thanks Kari!! 😃💕 Isn’t it cool? For a slug at least. Hehe… And yay!! LOVE hearing that you’ll be doing art this week!! You notice I ignored your “hoping to” part and will just smile happily assuming you’ll DO it! 😉👍🏻❤️

  12. Jacob 7 years ago

    Wow, ice cold. You know, when I first saw this, I thought it so beautiful that it was bound to be something hugely unpleasant, seems I was right… but this is an utterly captivating doodlewash! One to enjoy from a distance, no doubt!

    • Author

      Thanks Jacob! Lol… Yeah…it does have that, I’m too pretty to be good look to it. So many creatures are like that…many humans I guess as well come to think of it. Lol This and those humans are all best enjoyed from a safe distance. 😉

  13. debiriley 7 years ago

    love the blues you used here! brilliant !

  14. M. L. Kappa 7 years ago

    Horrid but cute! I wonder what its role is in the Eco- system…

  15. M. L. Kappa 7 years ago

    You are educating us, Charlie! I just had to look him up and one of the interesting facts was that “The ventral side of the organism, which actually floats on the sea surface due to the gas float in its stomach, is a brilliantly blue color matching the color of the ocean. The dorsal side, which faces downward into the ocean, is a silvery grey color to blend in with the surface, thus providing protection from predators”.
    Another you could do is the Porpita Porpita, or blue button, which is one of the poisonous jellyfish this slug feeds on. Just a suggestion:-)

    • Author

      That’s awesome!! Thanks so much for including the extra info. These little slugs are endlessly fascinating aren’t they? hehe Love this! Had never heard of a Porpita Portpita… looks like a flower almost instead of a living creature. The Janthina is also on the sea slug’s menu and look pretty cool as well!

  16. itsmyhusbandandme 7 years ago

    Love the colours of this little guy. Tho I wouldn’t like to meet him when he got hungry.

    • Author

      Thanks! Glad you like this… it was fun to play with all my blues. And I don’t think he’d eat you, unless you’re full of poison… lol… but a sting would definitely not be cool!

  17. Cathe 7 years ago

    What a beautiful and rather horrid creature. I love the blue and his/her floaty quality. Lovely doodlewash Charlie and such unique information!

  18. babybluesnowflake 7 years ago

    I guess, it needs to defend its obvious beauty somehow 😉 What blue(s) did you use for this doodlewash. Very pretty!

  19. memadtwo 7 years ago

    This one really looks like a plant…or maybe some glittery thing, waiting for the right costume to attach itself to! (K)

  20. Susan Feniak 7 years ago

    And such a lovely shade of blue too. Poisonous? Too bad. I would find that colour hard to resist if I were sharing the same water with it. Yikes!

    • Author

      Thanks, Susan! 😃💕Hehe… yeah… best not to touch one of these, regardless of the inviting color! Yikes is right!

  21. Tom Merriman 7 years ago

    ‘Glaucus Atlanticus’ sounds like a Roman gladiator!
    Another good one, Charlie… it’s odd though how something so uncommon can have so may names!

    • Author

      Thanks Tom! It does sound like a gladiator!! lol And yeah…it seems these unusual creatures end up with a ton of names. Guess nobody seems to agree on quite what to call them! Hehe

  22. Sharon Bonin-Pratt 7 years ago

    Such a pretty little poison – not one to invite to the swim party.

  23. kathiwerner 7 years ago

    What a colorful little slug!

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