Sea Urchins

Sea urchins are prickly-looking marine animals that are spherical in shape and covered in long movable spines. The most common species is purple or light pink. Sea urchins have podicellariae which are three jawed pinchers on top of slender stalks. They also have tiny tube feet projecting from its body surface. Their spines are used for locomotion and protection and their podicellariae are used for defense and for cleaning the body by removing larval animals and small crustaceans. Tube feet are the hollow muscular projections ending in suckers. Flexible and can be extended beyond the spines to grip objects on the ocean floor. Mostly found off the pacific coast of California, sea urchins can found on the oceans bottom usually near rocky shores. Another place commonly sea urchins are commonly found is coral reefs. Sea urchins feed on seaweed and other organic matter. On its under surface is a mouth with five strong teeth used in feeding. They also eat algae off of hard surfaces. These animals reproduce sexually by means of egg and sperm. Female sea urchins release million of tiny jelly-coated eggs into the water that are then fertilized by the sperm of the male. The tiny sea urchin eggs become part of the plankton and the sea urchin babies do not hatch for several months. The sea urchins purpose is to take care of the hidden algae in corals that kill the reefs. Some sea urchins use their tube feet to pick up small rocks, bits of shell, or seaweed. The animals arrange these objects so that they cover their bodies. By doing this, a sea urchin can blend in with its surroundings. This is a form of camouflage. It helps the sea urchin hide from enemies. Like most other spiny-skinned animals, sea urchins use their tube feet to move along the ocean floor. But sea urchins also use their spines to help them get around. A sea urchin sometimes squeezes into a hole between rocks. If a hole is too small, a sea urchin will use its teeth and spines to make it bigger. By carving out a bigger hole, a sea urchin can make its own little home. And it's usually a home that's too small for unwelcome visitors, such as sea stars and other enemies. Sea urchins belong to the class Echinoidea.