Also known as sea slugs, these shell-less molluscs are real gems because, more than any other marine animal, some have fascinating shapes, sumptuous hues and intricate patterns.
There are more than 3,000 species of nudibranchs and every day a new species is discovered. Some of these new species have not yet been identified.
Nudibranchs are found in all the oceans of the world, in warm or cold waters. They live at or near the bottom of the sea and have been found at depths between 30 and 6,500 feet below the surface of the ocean.
They are carnivorous. Their prey includes sponges, corals, anemones, hydroids, barnacles, fish eggs. Nudibranchs are difficult consumers and some species or families of nudibranchs can only feed on one type of prey. Some nudibranchs are even cannibals and devour nudibranchs of their species or neighboring species.
Some nudibranchs, like the Blue Dragon, create their own food by eating coral and seaweed. The nudibranch absorbs the chloroplasts of the algae (zooxanthellae) which acquire these nutrients by photosynthesis using the sun which allows the nudibranch to stay luminous for months. Others have developed different methods of cultivating zooxanthellae, harboring them in their digestive glands. These are nudibranchs that live close enough to the surface to make the most of the sunlight.
They have the reproductive organs of both sexes. Since they can not go too far, or too fast, it is important that they can reproduce when the opportunity arises. Having both sexes means that they can mate with any adult nearby.
They lay egg masses in the form of spirals or spirals, which are mostly left on their own. The eggs hatch into free-swimming larvae and eventually settle to the bottom of the ocean as adults. Only one species of nudibranch, Pteraeolidia ianthina, has parental vigilance in protecting masses of freshly laid eggs.
Nudibranchs are not very good at swimming. Some use a "foot" to move to the ocean floor. And at each passage, they leave a long trail of mud behind them.
Nudibranchs get their color thanks to their diet. These colors can be used to camouflage or warn predators of the poison they contain. Not all species are, however, toxic.
Having difficulty distinguishing light from darkness, nudibranchs use chemical signals to locate food and other objects, using a pair of horn-like palps on their heads.
unfortunately, they live only a few weeks, and up to a year for some species.