Meet The Most Beautiful Sea Slugs

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Do you know what these crazy colorful creatures are? They’re some of the most overlooked beauties in the deep void that is the ocean.

But don’t let their looks fool you, some of these guys have the ominous super power of being able to eat the most highly poisonous creatures on the planet and then harvest their prey’s toxins for themselves.

Making them some of the most beautiful predators in the open seas. They’re called nudibranchs. Which are soft-bodied marine gastropod mollusks part of the sea-slug family.

They’re pretty tiny, ranging from about a quarter inch to twelve inches long. And there are over 3,000 species of these guys.Talk about a big family.


The name “nudibranch” actually means “naked gills”. Which refers to the exposed gills that sprout out of their backs. But some species of nudibranchs can retract their gills in order to protect them.

They’ve got no eyes, but instead have two tentacles, called rhinophores, located on top of their head. These things are super sensitive to touch, smell, and taste, which helps the nudibranch navigate its surroundings and locate prey and mates.

And they have two of them so they can tell from which direction a scent is coming from based on the intensity on each rhinomphore. Most mollusks—like snails, clams, and oysters—have hard shells as a means of protection.


But not the nudibranch. They actually ditch their shells during the larval stage in favor of other defense mechanisms. Which actually has a lot to do with their wild colors.

Nudibranchs derive their colors from the things they eat. Which includes sponges, anemones, and even other nudibranchs. The colors act as a warning sign to potential predators since the bright colors are often associated with poison.

But some nudibranchs don’t just look poisonous. They might be poisonous for real. In addition to adopting the color of their prey, nudibranchs can also retain the toxic chemicals it ingests and save it for themselves.


The blue dragon is an especially toxic nudibranch. This guy eats the Portuguese Man O’ War, which is a venomous jellyfish-like ocean floater.

Once the blue dragon ingests the man o’ war, it concentrates its stinging cells and stores them in its long external outgrowths. And the blue dragon can actually accumulate a large number of these stinging cells, which makes them even more dangerous than the man o’ war itself.

In other words, some nudibranchs are poisonous and inedible, while others just pretend to be. Which is actually a solid strategy if you ask me.

Now, as with all strange creatures of the deep, you may be wondering how these guys reproduce. Nudibranchs are actually hermaphrodites, which means they have a set of male and female reproductive organs allowing them to mate with any other mature and consenting member of their species.


And a mating couple can produce up to 1 million eggs at once. So where can you see some of these things for yourself?

All over the world, really. And at all depths. But they do tend to favor warm temperate and tropical seas. Although some species have even been found in Antarctic waters.

Actually, new nudibranchs are identified almost daily. So who knows, maybe you’ll discover one for yourself. What would you name a nudibranch if you had the chance?