Despite their name, Red Sea Urchins can range in color from pink to deep red to purple. These large urchins have long, straight, smooth spines. This species of invertebrate is related to sea stars, California Stichopus (Sea Cucumbers) and Sand Dollars.
Urchins eat a variety of brown and red algae but prefer giant kelp, Macrocytis. They have movable jaw parts called an Aristotle’s lantern that cut seaweed into portions small enough for them to ingest. Like sea stars, urchins move with their tube feet.
Red Sea Urchins can be found Alaska to Baja California. They are uncommon in the very low intertidal zone but become more abundant sub tidally to a depth of 295 feet (90 m). Juvenile Red Sea Urchins are often found beneath the outspread spines of adults.