Purple Sea Urchin
The sea urchin's name comes from the Old English word for spiny hedgehog. It looks like one because of its spines, which are used for protection. The purple sea urchin is about 4 inches across, with spines up to 1.5 inches. It is bright purple. The hard, outer body is called a test, with bumps and holes which the movable spines and tube feet extend from. It can move surprising fast on its tube feet, which are its main means of moving. The sea urchin's mouth is on the lower surface and it uses a feeding system, called Aristotle's lantern, which is made of 5 hard plates that form a beak. The beak-like mouth is used to scrape algae off rocks.
Sea urchins eat plankton, kelp, periwinkles, and even barnacles and mussels. On the other hand, birds, sea stars, cods, lobsters, foxes and sea otters eat sea urchins and they are even used as food in Asia and South America.
They live in sheltering holes in rocks. They can grow new "teeth" if the old ones break or wear down. Sea urchins belong to the same group as sea stars, sand dollars, sea lilies and sea cucumbers. They are beautiful but deadly animals.
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