SEA URCHINS
Sea urchins belong to the family Echinoidea, meaning "spiny skinned creatures", to which there is more than 700 sub-species. These sub-species live almost all over the world in shallow, rocky waters where it is often too cool for coral to grow.
Sea urchins are covered with sharp, poisonous spines that make them look like small porcupines or pin cushions. These spines provide protection and help the sea urchins move. In between the spines are soft tube feet that end in suckers that are good for moving and holding onto things. The spines bases are connected to a number of large plates that fit together closely to form a hard shell called a test. The tests may be black, dark brown, olive-brown, reddish-brown, purple, violet, muddy yellow, white or green. They may also have blue, red or white stripes or spots. At the bottom of the urchin is the mouth, called an Aristotle�s lantern, which consists of five converging jaws. With the help of these five jaws, it�s sucker feet and spines some sea urchins can carve hiding places out of rock, coral, even steel.
Not many animals eat sea urchins because of the poisonous spines on the sea urchins test. Those animals that do eat sea urchins use tricks to flip the sea urchins over and expose the vulnerable underside. Queen triggerfish, for example, suck in water, then shoot it out in sudden bursts at a sea urchin to flip it over. The Queen triggerfish then swims in, kills and eats the sea urchin. Other animals, like wolf eels, have mouths hard enough to crush the sea urchins spines and test. Big surprise, humans eat sea urchin as well. The ovaries of some species are eaten raw or fried in the West Indies, and in the Mediterranean area the egg mass of one species is eaten under the name of frutta di mare. On the U.S. Pacific coast, eggs of the giant purple (or red) urchin are considered a delicacy. Also on the U.S. Pacific coast is a sea urchin sub-species known for carving hiding places out of steel pilings.
Sea urchins are voracious eaters. They eat seaweed, various plants, and especially love algae. A group of sea urchins can turn a forest of seaweed into an underwater desert in a matter of minutes.
When a sea urchin dies, it�s spines break off and the soft parts rot away, leaving only the empty, spineless test that is all most people ever see of a sea urchin.
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