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blue sea dragon

The Blue Sea Dragon

  • 22 May, 2020
  • Critterman
  • 9 Comments
  • 8906 Views
  • 37 Likes
Daily Critter Facts, Fish Facts

The blue sea dragon, aka sea swallow, blue glaucus, blue sea slug, blue angel, and blue ocean slug, is a nudibranch that calls the Pacific, Atlantic, and Indian Oceans its home. They prefer temperate and tropical waters and pack a punch. They may be small, they may look delicate, but they hide a secret. The exotic pet trade, pollution, and ocean acidification are all causing these cool critters to dwindle in numbers. They are listed as Endangered by the IUCN.

First the Stats…

Scientific name: Glaucus atlanticus
Length: Up to 1.2 inches
Lifespan: Up to 1 year

Now on to the Facts!

1.) They are pelagic (float upside down).

2.) These critters float by swallowing air.

3.) Blue sea dragons prey on the Portuguese Man-o-War and siphonophores.

4.) A group of sea dragons is called a blue fleet.

5.) Sea dragons feed on and reuse the stinging nematocysts of their prey to their defensive advantage.

But wait, there’s more on the blue sea dragon!

6.) When these diminutive creatures reuse the stinging cells of their prey, they actually intensify their potency.

7.) The blue glaucus is a hermaphrodite (produce eggs and sperm). However, they do need to mate with another dragon in order to produce eggs.

Did you know…?
If threatened, the blue dragon nudibranch can inflict a potentially lethal sting… multiple times.

8.) After mating, both blue sea slugs produce eggs to later be fertilized.

Now a Short Blue Sea Dragon Video!

Also, check out the Critter Science YouTube channel. Videos added frequently!

Want to suggest a critter for me to write about? Let me know here.

Learn more about all kinds of cool critters, right here!
Atlantic Oceanblue sea dragonIndian oceannematocystsnudibranchPacific Oceanpredatorsea slug
Critterman

With over 50 years of critter experience to my credit and hundreds of zoology teaching hours to people around the world, I have amassed not only a continuing thirst for critter knowledge but a desire to teach others all I can about the majesty and wonder of our natural world. Critter Science is a culmination of such knowledge. I have hands on as well as book acquired intel on all kinds of critters. Whether they're on land, sea, or in the air. I will never say that I know everything about all animals. That's impossible, even for a savant. But, that being said, ask me any animal question and I'll answer it. If I don't know the answer, I'll get an answer for you!

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9 Comments
  1. Reply
    Eammon Ferringer November 15, 2022

    about how many are usually found together?

    • Reply
      Critterman November 16, 2022

      Sans during mating, these critters are solitary.

  2. Reply
    Ellie October 25, 2022

    what is the biggest one ever found?

    • Reply
      Critterman October 26, 2022

      Hi, Ellie. They can get up to 1.18 inches long.

  3. Reply
    borange December 7, 2021

    This is very useful!

  4. Reply
    Ariana November 18, 2021

    Does the blue glaucus do anything intelligent?

    • Reply
      Critterman November 19, 2021

      Not necessarily “intelligent”. Rather they help to control certain species of jellyfish by eating them and then using their stinging nematocysts as a defense.

  5. Reply
    emily October 28, 2021

    can I come and work for you

    • Reply
      Critterman November 1, 2021

      I appreciate the offer. Right now we aren’t hiring. But I’ll keep you in mind, for when we are.

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