Sea Urchin Facts
Sea urchins are marine animals found in tide pools and along the ocean floor. A sea urchin's body is spherical and spiny. Sea urchins come in an assortment of colors such as green, purple, red and black.
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Classification
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Sea urchins are echinoderms, or animals with spiny skin. Other echinoderms include sea cucumbers, sand dollars and starfish. All echinoderms are invertebrates because they lack a spine.
Features
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Sea urchins have tube feet, meaning they are small and hollow. Urchins use their sticky spines and tube feet to move and then adhere to surfaces. The sea urchin's mouth is on the bottom of its body. The mouth has five triangular teeth arranged around the oral opening. Sea urchins eat mostly algae.
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Defense
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Sea urchin spines can hurt other creatures but are not venomous. In between the spines are microscopic, venomous pedicellariae that have three jawlike pinchers on a stalk. These pedicellariae are also used to grasp food.
Ecology
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When urchin populations within tide pools grow unchecked by predators, it causes an urchin barren. The urchins will eat all of the algae, seaweed and kelp in the area, which leads to a decrease in habitat for other marine animals and an increase in erosion.
Uni
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Sea urchin is often eaten as sushi called uni. Primarily, the gonads containing the urchin's eggs are eaten. Sea urchin is in high demand in Japan, where it is considered a delicacy.
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References
Resources
- Photo Credit U.S. Fish and Wildlife Service
