Nudibranch
Nudibranchs, or sea slugs, belong to a group of animals called ‘gastropods’ (meaning ‘stomach foot’) but lack the shell of others in this group.
Meaning ‘naked gills’, most nudibranchs display feathery appendages on the outside of their body that have replaced internal gills. These external gills should not be confused with the two small tentacles on their head,
which resemble antennae in some species. These tentacles are used as chemical sensors to ‘smell/taste’ chemicals in the water.
Found throughout Western Australia, nudibranchs are carnivores, feeding on animals such as sponges, soft corals, anemones and hydroids.
Most nudibranchs are brightly coloured and patterned, which can provide camouflage or warn off predators. Nudibranchs may also protect themselves by excreting a foul-tasting toxic chemical and some species utilise the stinging cells (or ‘nematocysts’) from their prey for future use.
All nudibranchs are ‘hermaphroditic’, which means the same animal acts as both male and female. Reproducing as a mating pair, the nudibranchs exchange sperm sacs through a tube. Each nudibranch will then lay egg masses that can contain millions of eggs.