I want to share with you all this awesome creature. Some of you might have seen it before as it’s been in several articles on bizarre or crazy looking species. It’s definitely unique. I wouldn’t have been surprised to see it floating around in an Avatar movie, but no, it’s here on our own Earth where we can find the beautiful blue sea slug (Glaucus atlanticus), often otherwise known as the sea swallow, blue angel, blue glaucus, blue dragon, and blue ocean slug. There is another species that looks very similar called Glaucus marginatus, though it is darker and has a different arrangement of “teeth” on the skin. The whole Glaucidae family has some pretty interesting members, actually.
Back to our buddy the blue dragon, as it’s common name states, this is a slug. Certainly not what I think of when I think ‘slug’, but here it is! It’s also an ocean variety. These creatures are one of the smallest of their biological family, reaching only 3 centimeters (1.2 in) in length.
There are two things about this blue angel that I find quite interesting. The first is that it floats upside down on the surface of the water. This is due to a gas filled sac located in the stomach that keeps the animal afloat. This is why their coloration is reverse what you’d often find in the oceans. Take the great white shark; darker on top and lighter on the bottom. Many animal species are like this. It’s a form of protective camouflage as, if you were looking down into the water at the animal, its upper dark skin would blend in with the darker ocean, but if you were looking up, its lighter belly skin would blend in with the lighter water and sky. The blue sea slug, then, has a dark belly and a light back.
The other interesting thing about these creatures is what they eat; things like Portuguese Man o’ Wars (Physalia physalis), which are known for being highly venomous and very dangerous to humans, along with some less dangerous by-the-wind-sailor (Velella velella), blue button (Porpita porpita), violet snails (Janthina janthina), and sometimes even each other. These little blue slugs can not only consumer a Man o’ War due to their immunity but they then are able to select and store the most potent of the venomous nematocysts in specialized sacs at the end of the slug’s fingers, or cerata, for their own use. In this form it can be highly concentrated and very dangerous!
While these animals can be found all over the world, from the waters off Hawaii to Africa to Europe, they are often not seen despite being on the surface due to not usually coming near shore, in combination with their small size and colorization. However, apparently some people have decided that they make cool pets.
Blue sea slugs, the tiny ocean dragons, are pretty awesome looking. I have one as my computer’s wallpaper right this very minute! Avatar’s Pandora might seem like a pretty awesome place filled with vibrant, strange animals, but we really need go no further than our own natural environments to find some pretty fascinating creatures of our own.