A diagram of a sea star showing the stomach and digestive organs.

Habitat

All echinoderms live in salt water like in oceans and seas. They are in every ocean except for the Polar Regions, where they cannot survive due to the temperature. Most adult echinoderms live on the ocean floor in salt water feeding on different sea animals. Many echinoderms can be found in tide pools along beaches or in oceans and beaches. The tide pools can support a variety of echinoderms and is changed every time the tide goes out.

Not all echinoderms consume food the same way. Sea stars will pry open mussels or clams to get to the inside. They can open the shell or valves one-tenth of an inch apart and still are able to consume it. After prying it open, the sea star will insert its stomach into the shell and release digestive enzymes that kill the animal. Then, the digested material is into the stomach and then into digestive glands in the arms. Sea cucumbers feed differently from other echinoderms. Some sea cucumbers will position themselves in a current bringing food and stay there for hours. They bring each tentacle to its mouth and "licks" it while the other tentacles are collecting food. Other sea cucumbers feed by sifting through soil or sand with their tentacles.