SEA SLUGS ALIENS OF THE OCEAN MARINE INVERTEBRATES
Most creatures known as sea slugs are actually sea snails
Slugs probably call the idea of brown and sticky garden gastropods to mind. However, their marine relatives dazzle with diverse and bizarre colours and shapes
The glossodoris cincta has regional colour forms:
Depending on where it lives, the Glossodoris cincta is found in three different colours. All have mottled brown bodies and gills, but the edge of the mantle can vary in colour: with or without a bluish-white band or with a yellow-black band that merges into a dull khaki shade.
The pilgrim hervia prefers to live on rocky bottoms and slopes
Thin and slender, with a long and sharply pointed tail, the Cratena peregrina (or pilgrim hervia) is a sea slug native to the Mediterranean. The spines along its back are known as dorsal cerata, and in this species can be found in many colours, though the tips are typically iridescent blue.
The felimare cantabrica feeds on sponges
Pictured here resting on a yellow cluster anemone in the Atlantic Ocean, the Felimare cantabrica has a light and dark blue body, dotted with yellow lines and flecks. Found in the eastern Atlantic Ocean, this sea slug has been observed feeding on sea sponges.
An underwater polka dot alien
The Goniobranchus hintuanensis, with its pale body covered in white rounded nodules and reddish-purple rhinophores (scent receptors), looks like a creature straight out of a science fiction novel. It can be found browsing the seabed for sponges.
Bright colours help sea slugs hide from predators
Coral reefs are varied and colourful places full of life, so a sea slug needs to be similarly bright to disguise itself from watchful predators. Their bodies can feature any colour of the rainbow, and these colours are primarily used for camouflage rather than warning of poison or venom.