Weird Wildlife Wednesday: Glaucus atlanticus
Meet Glaucus atlanticus.
Species: G. atlanticus
This thing might look like a gigantic Ice/Dragon Pokémon, but it is actually a kind of slug and only about 4 cm long. Making its home in most temperate and tropical waters on earth, Glaucus atlanticus floats upside down under the surface of the water buoyed by a gas bubble and preys upon Physalia such as the Portuguese Man o’War. Like many aeolids, those cool appendages, called cerata, store the nematocysts, or stinging cells, from venomous species in a sac (cnidosac) at the end of each ceras. Retaining only the most venomous nematocysts, a sting from Glaucus atlanticus is much more concentrated than that of its prey.
Stealing energy from the enemies that you consume? If you ask me, that’s kind of evil… but aww look how cute it is when it’s dry.
When out of the water, Glaucus atlanticus shrinks up and looks a bit like Stitch from the Disney film, Lilo and Stitch.
Glaucus atlanticus also has an even tinier cousin, Glaucus marginatus that only grows up to about 17 mm in length.
Both species exhibit excellent examples of countershading (like sharks, whales and dolphins). From above G. atlanticus and G. marginatus appear blue and white, to match the color of the sea. Below the surface of the water, the true dorsal side (as they invertedly float) is a a greyish-silver to match the the appearance of the sky refracted through the water.
Deadly, awesome, and yet strangely adorable.