About Sea Stars

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Photograph by Lawson Wood/CORBIS

Learn About: Sea Stars

My friend Stella is a beautiful creature called a sea star. Some people call her a starfish because of her star shape. But she and other sea stars are not fish at all. The sea star is an invertebrate (which means it doesn’t have a backbone). It also doesn’t have blood. Filtered sea water moves nutrients through the animal’s body. Instead of brains, they have a nervous system that spreads through their arms. Sea stars also have hard skin that can protect them from predators. Predators are other animals that might eat a sea star.

Where Do Sea Stars Live?
Sea stars live in all kinds of habitats, from shallow tide pools on the rocky shore to deep ocean waters. They live alone, although they can be found clustered together where there is food. They only live in salt water.

Why Do They Look Different From Each Other?
There are over 1,000 species, or different kinds, of sea stars and there are many different colors and sizes of sea stars. Some sea stars can be more than three feet (one meter) across! They can live a very long time—up to 35 years in the wild.

What Do Sea Stars Eat?
Sea stars most often eat small mollusks, or shellfish, such as clams or snails. They pull clam shells open with their arms, then use their stomachs to eat the clams.

Marmo's Tip: Help keep beaches clean. When you go to the beach be sure to leave it cleaner than when you got there. Don't leave any trash and ask your parents if you can pick up bottles and plastic that you find on the shore. Stella will appreciate it!