NUDIBRANCHS
The naked beauties of the sea
Ready to be amazed? I am sure this group of sea creatures will blow your mind: Nudibranchs are molluscs, and are related to snails and slugs. The word nudibranch comes from the Latin nudi – naked and the Greek brankhia– gills, which refers to the exposed gills on the back of their bodies. They are mostly benthic, which means they crawl over pretty much any surface in the ocean from coral reefs to mangroves. But they can also release their grasp and drift with the currents, usually to escape predators. Some of them are also able to swim! They have tentacles with which to taste and feel their surroundings, and antenna-like appendages that act like a nose to detect chemical signals. Nudibranchs come in pretty much any colour and body shape there is. There are over 3000 known species and each one is more beautiful than the next.
They feed on pretty much everything, from bacteria, algae and seagrass, to sponges, worms, molluscs, crustacea, fish eggs and even other nudibranchs. One really cool fact about them is that they can be “solar powered”. They can absorb chloroplasts from algae they eat and store them so that they can use the nutrients generated by photosynthesis!
By being the “naked” creatures of the sea, one would think that they are pretty defenceless and that anything can eat them. But nothing farther from the truth. Nudibranchs have adapted in many ways to protect themselves. Apart from some species’ ability to swim, nudibranchs either create their own poison or use toxic substances from their prey (e.g. toxic sponges) to deter predators. The species Glaucus atlanticus (see first drawing) eats Portuguese man of war, a very poisonous jellyfish, and retains its venomous cells so that it can then use them to sting predators. Nembrotha cristata (see third drawing) can also deliver painful stings with in this way. If you ever see one of these – think twice before touching them, it could sting!

If you want to know more about these amazing creatures or see some great pictures check out the following links: Photos / Video


Author: Dr. Tania Mendo
Illustrator: A. Loth