Nudibranch facts for kids

Quick facts for kids Nudibranch
Berghia coerulescens
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda

Nudibranchs (Nembrotha kubaryana) eating clavelina tunicate colonies. They can also use stinging cells from jellyfish they eat.

A black-spotted nudibranch from Haiti.

Chromodoris willani from Lembeh Straits, Indonesia.

Cerberilla ambonensis, a nudibranch that burrows in the sand, found in East Timor.

Nudibranchs are a type of mollusc that lives in the sea. They are also known as sea slugs. The name "nudibranch" means 'naked gills'. This is because they do not have a shell like many other molluscs. Instead, their gills are often visible on their bodies.

Nudibranchs are famous for their bright and beautiful colors. There are more than 3,000 known species of nudibranchs. They come in many different shapes and sizes.

About Nudibranchs

Nudibranchs are part of a group called opisthobranchs. This means they lose their shells after they are born as larvae. Unlike most other molluscs, nudibranchs have bodies that are the same on both sides. This is called bilateral symmetry.

What Nudibranchs Eat

Most nudibranchs are carnivores, meaning they eat other animals. They have a simple gut and a mouth with a special scraping tongue called a radula.

• Some nudibranchs eat sponges.
• Others eat polyps, which are tiny animals like corals.
• Some eat other sea slugs or even members of their own species.
• Other groups eat tunicates, barnacles, or anemones.

One special nudibranch, Glaucus atlanticus, lives on the surface of the water. It eats dangerous jellyfish like the Portuguese man o' war. This nudibranch sucks air into its stomach to float. It uses its strong foot to hold onto the water's surface. If it finds a small victim, Glaucus simply eats it whole. If the prey is larger, it nibbles off the stinging parts.

Amazing Colors and Defense

Flabellina pedata, a colorful nudibranch from East Timor.

Nudibranchs are some of the most colorful creatures on Earth. Since they do not have a shell for protection, they have developed other ways to defend themselves.

• Camouflage: Some nudibranchs blend in with their surroundings. Their bodies look like the plants or rocks around them. This helps them hide from predators.
• Warning Colors: Many nudibranchs have very bright and intense colors. These colors warn predators that the nudibranch is distasteful or poisonous. This is called warning coloration.
• Stinging Cells: Some nudibranchs eat animals called hydroids. Hydroids have stinging cells called nematocysts. The nudibranchs can store these stinging cells in their own bodies. They move the cells from their gut to their skin. Then, they use these stolen stinging cells to protect themselves!
• Sour Liquid: Another way nudibranchs protect themselves is by releasing a sour liquid from their skin. If a predator touches or irritates them, they automatically release this slimy liquid.
• Using Plant Power: Some nudibranchs can even take chloroplasts from plants they eat. Chloroplasts are parts of plant cells that make food using sunlight (photosynthesis). The nudibranchs can use these chloroplasts to make their own food!

Different Kinds of Nudibranchs

Chromodoris willani is a dorid nudibranch. Dorids breathe using the feathery plume on their back.

The Spanish shawl, Flabellina iodinea, is an eolid nudibranch. It has many cerata on its back, used for defense and breathing.

Nudibranchs are often called dorid or eolid types.

Scientists are still studying how to group all the different types of nudibranchs. But generally, nudibranchs are divided into two main kinds: dorid nudibranchs and aeolid or eolid nudibranchs.

• Dorid Nudibranchs: These nudibranchs have a feathery cluster of gills on their back, usually near their rear end. This cluster is called a branchial plume.
• Aeolid Nudibranchs: Instead of a branchial plume, aeolids have many finger-like parts on their backs called cerata. These cerata help them breathe and can also be used for defense. Some aeolids even host tiny plant-like organisms called zooxanthellae inside their cerata. These zooxanthellae make food using sunlight, which helps the nudibranch.

The frosted nudibranch Dirona albolineata.

Images for kids

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  Janolus sp. in Anilao, the Philippines.

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  Kalinga ornata from Anilao Pier dive site, depth 5 m.

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  Berghia stephanieae nudibranch body: Note the oral tentacles (ot), foot tentacles (ft), eye (e), rhinophores (r), and cerata (c). This species has cnidosacs (cn) at the cerata tips. Scale bar is 100 μm.

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  The Glaucus atlanticus is an example of a nudibranch that has its cerata positioned like wings instead of on its back.

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  Mating behavior in Nembrotha purpureolineata.

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  Acanthodoris lutea laying eggs.

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  Pteraeolidia ianthina has adapted cerata to house symbiotic zooxanthellae obtained from its diet, which continue to photosynthesize and provide energy to the nudibranch.

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  1852 watercolor of a Nudibranch by Jacques Burkhardt.

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  Tritoniopsis elegans.

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  Nembrotha cristata, in Bunaken National Park.

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  Clown nudibranch Triopha catalinae, Northern California.

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  Chromodoris annae from Lembeh Straits, Indonesia.

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  Spanish dancer taken at night, Red Sea.

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  Nembrotha chamberlaini from Verde Island, the Philippines.

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  Glossodoris atromarginata.

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  Chromodoris dianae from Verde Island, the Philippines.

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  A pair of Nembrotha milleri mating at Verde Island, the Philippines.

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  Regal sea goddess Felimare picta in the Gray's Reef National Marine Sanctuary, Savannah, Georgia.

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  Flabellina affinis at La Herradura (Mediterranean Sea) Spain.

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  Dorid nudibranch egg ribbon in Moss Beach, California.

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  Nudibranch egg ribbon at Shaab Mahmoud (Red Sea, Egypt).

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  Nudibranch egg ribbon at Malahi (Red Sea, Egypt).

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  Goniobranchus kuniei, off the coast of Papua New Guinea.

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  Nudibranch.

See also

In Spanish: Nudibranquios para niños