You might think, when I say “blue sea slug,” that what I’m going to show you is going to be… well… a slug. Like a banana slug, perhaps, only… blue. And you would be so incredibly wrong.
Really, when you think about it, I could fill the rest of my days writing Featured Creature Friday blogs about the bizarre and wonderful inhabitants of the oceans, because if there’s one place that animal adaptations take a turn for the bizarre, it’s in the sea. But we must truly begin with the blue sea slug, which at the moment is my favorite of ocean creatures, for reasons I’ll get into below. The first reason, of course, is that blue sea slugs are insanely beautiful. If you were going to make a movie with some exotic and beautiful alien creatures, you’d do well to start your search for inspiration with one of these:
They’re also unexpectedly tiny, only a few centimeters in length, with six separate appendages, each with its own collection of cereta — those little finger-like structures. It has serrated teeth. But wait, it gets even more bad-ass. Blue sea slugs not only prey on animals much larger than them, they actually prey on jellyfish (which as we’ve previously discussed are the enemy). Their most notable snack is the notorious Portuguese Man o’ War. They also eat blue buttons and purple snails and some other stuff, but mostly jellyfish. Bless them.
But they don’t stop with just devouring jellyfish. They continue to be crazy-incredible. Because when they’re eating the jellyfish, they ingest the nemocysts — the cells which produce the jellyfish’s sting — and store them in their own little fingers. And then? They use them as weapons in their own defense. They can actually be more venomous than the Man o’ War they feed on. It is possible that they are the most bad-ass tiny animals ever.
Aside from their excellent killer instincts, they have some other sweet features. They have gas-filled sacs in their bodies which they use to float on the ocean’s surface, but due to the location of said sacs they actually float upside down. All they need to make their lives more complete, clearly, is a tiny sea-slug-sized version of beer. Their sweet silvery-blue coloring is thought to be protective coloration that makes them difficult to spot for both sea birds above and fish below. They’re also hermaphroditic, which isn’t really all that amazing for strange little ocean creatures but is kind of interesting anyway. These little fellows are pretty common in temperate and tropical ocean zones, and you’re most likely to see them around Africa, Europe or Australia, but I’m hoping that in the event of the inevitable jellyfish invasion, they’ll be willing to travel…