Sea Urchins look like round, spiny balls (usually 1-4 in across). They can be found in oceans around the world but are much less common in the cold polar areas. They have hard shells and use their tube feet to crawl along the sea bed. Their spines help protect them from predators but also help them to move about and to trap food particles.
Sea Urchins have a mouth on the underside of their body with 5 teeth they can use to grab, scrape, pull, and tear. Sea Urchins eat both plant and animal matter, such as seaweed, algae, and dead animals.
Sea Urchins are closely related to Sea Stars and Sand Dollars that also have radially symmetrical bodies.
There are many different species of Sea Urchins. Red Urchins have long spines and can live more than 200 years. Green Urchins have very fine, short spines and can be found in calm areas without too much wave activity. Purple Urchins prefer areas with a strong surf and are common in the Atlantic Ocean.
Did you know? Sea Urchins breathe through their tube feet.
See Also: Barnacle, Blue Mussel, Clam, Crab, Harbor Seal, River Otter, Sand Dollar, Sea Anemone, Sea Jelly, Sea Lion, Sea Otter, Sea Star
