Here is a diagram of the body of a sea star. You can clearly see the stomach, anus and the tubed feet.
Fun Fact: There are some 2,000 species of sea star living in all the world’s oceans, from tropical habitats to the cold seafloor. The five-arm varieties are the most common, but species with 10, 20, and even 40 arms exist.
Fun Fact: There are some 2,000 species of sea star living in all the world’s oceans, from tropical habitats to the cold seafloor. The five-arm varieties are the most common, but species with 10, 20, and even 40 arms exist.
Here you can observe a sea star using the suction cups on their tube feet to pry open the bivalve's shell. The sea star turns it stomach inside-out to eat its prey.
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Sea urchins have little claw-like structure among their spines which the sea urchin uses for protection.
Fun Fact: These structures (known as pedicellarines) are small stinging structures that are not only used for defense and obtaining food, but are also vital in keeping the body of the sea urchin clean. |
Fun Fact: When threatened, some sea cucumbers discharge sticky threads to trip up their enemies. Others can mutilate their own bodies as a defense mechanism. They violently contract their muscles and excrete some of their internal organs out of their anus. The missing body parts are quickly regenerated.