Notes

The Blue Glaucous (Glaucous Atlanticus), sometimes called the blue sea slug, or blue ocean slug, is a bizarre-looking marine creature in the group of sea slugs known as Nudibranchs. Found in the temperate and tropical waters of the Pacific, Atlantic, and Indian Oceans. This slender creature is up to 3 centimetres long. The Blue Slug lives its life floating upside-down on the surface of the ocean thanks to an air bubble which it swallows and keeps inside its stomach. Its colour pattern helps it avoid both flying and swimming predators while floating wherever the wind and the currents take it: its underside, which faces upward, is blue; helping it blend into the water’s surface when seen from above, while its back, which faces downward, is a more greyish colour; helping it blend into the ocean when seen from below. This camouflage is not the blue Glaucous’ only form of self defence. It feeds on animals known as Hydrozoans, especially the highly venomous Portuguese Man-O’-War. Although a sting by a Portuguese Man-O’-War is very painful to a human, The Blue Glaucous, like some other Nudibranchs, can swallow its prey’s stinging cells (known as Nematocysts) without hurting itself. It may be able to protect itself from the sting both by stashing mucus and by hard discs in its skin. Far from being harmed by the poison, The Blue Glaucous stores it in the up to 84 finger-like structures sticking out of its body, and uses it to defend itself against predators.