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Spanish dancer

life science Maturity 7-9 Next article →

The Spanish dancer is a very large sea slug. Its science name is Hexabranchus sanguineus. This name means blood-colored six-gills.

It belongs to a group called nudibranchs. These are colorful marine mollusks. They are part of the Hexabranchidae family. This slug is special because of its bright colors. It can grow to a length of 25 cm. Some reports say they reach 40 cm in the Red Sea.

This animal has a very interesting way it works. It has a soft and flat body. Two small parts called rhinophores sit on its head. These parts can pull back inside the body. On its back, it has six gills. These gills can also contract or pull in. When the slug crawls, its edges curl up. This makes a shape like a small blister.

Scientists have studied this slug for a long time. They first described it in 1828. For many years, people thought it was one single type. However, a study was published in 2023. This study looked at DNA and body shapes. It found that the name H. sanguineus actually covers five different species. This new discovery changed how we see these dancers.

These slugs live in many warm parts of the ocean. You can find them in the Red Sea. They live in the Western Indian Ocean too. They also inhabit French Polynesia and the Western Pacific. They like to stay near rocky or coral reefs. These homes are usually 1 to 50 meters deep.

They hide in dark cracks during the day. They only come out to move at night. They spend their night eating sponges from the Halichondriidae family.

The Spanish dancer has a clever way to stay safe. It eats sponges to get a strong chemical. It uses this toxin to protect itself. The slug even puts these chemicals into its egg ribbons. These ribbons are bright red or pink and spiral in shape. This keeps the eggs safe from other nudibranchs.

You might also see an emperor shrimp living on the slug. This shrimp is a commensal, which means it lives near the slug. The slug's movement also helps it escape. It unfolds its edges and swims with waves of its body. This looks just like a dancer.

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