Sea Slug

Fascinating facts about the Sea Slug

• Glaucus atlanticus hoards the stinging cells of its prey and redeploys them from the finger-like cerata on its back. It steals nematocysts from creatures such as the Portuguese man o' war, blue buttons and by-the-wind sailors, keeping the toxic capsules intact. The bright colours of this nudibranch serve as a warning that those stored nematocysts can be used for defence. By keeping the cells in its cerata, the slug gains a potent deterrent against predators.
• The lettuce sea slug, Elysia crispata, harvests chloroplasts from the algae it consumes and runs photosynthesis inside its own body. This kleptoplasty lets the slug turn sunlight into sugars, effectively borrowing the algae's energy-producing machinery. Its distinctive lettuce-like ruffles line the body and dramatically increase surface area, allowing the stolen chloroplasts to capture more light.
• The California black sea hare, Aplysia vaccaria, can reach a length of 75 centimetres and weigh up to 14 kilograms, making it the largest known sea hare. Like other sea hares, it possesses several defensive strategies beyond its natural toxicity. When threatened it can eject a foul-smelling ink and also secrete a viscous slime that deters predators. These combined defences, together with its size, give the black sea hare a strong chance of surviving attacks.
• Sea slugs possess a true brain, and in the California sea hare Aplysia californica the brain is composed of roughly 20,000 nerve cells. Like all gastropods they also have a small, razor-sharp radula for feeding and a pair of rhinophores on the head that act as smell-sensing tentacles. Their sensory organs include a tiny eye at the base of each rhinophore, giving them basic visual input as they crawl over reefs.
• A few acochlidian sea slugs have left the ocean, adapting to freshwater streams where they continue to feed and reproduce, and at least one lineage has even colonised terrestrial habitats. These transitions show that the loss of a protective shell does not confine all sea slugs to marine environments, allowing some groups to exploit entirely new ecological niches beyond the sea.

Sources

Every fact above was checked against these pages, and kept only where one of them states it.

• Wikipedia

At a glance

About the Sea Slug

As the sea slug glides effortlessly across the ocean floor, its vibrant, iridescent body undulates with each gentle wave, like a living embodiment of the sea's own rhythmic pulse. With a quiet, almost ethereal elegance, it navigates the coral reef's intricate labyrinth, its slender foot leaving behind a trail of silvery slime as it searches for the algae and plankton that sustain it. In this tranquil, sun-dappled world, the sea slug is a master of subtlety, its very existence a testament to the beauty and diversity that thrives in the ocean's hidden depths.

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