About the Chiton

A chiton is a primitive mollusk with a hard shell. Chitons can be found in salty bodies of water around the world in both cold and tropical zones. They live mainly in intertidal areas, which are above water at low tide and below water when the tide is high. Chitons cling to rocks to avoid being swept away.

  1. The Shell

    • The chiton's shell is its most distinctive characteristic. The shell is composed of eight plates, called valves, that can adjust to allow the chiton to curl up into a ball. The valves, made of magnetite, are embedded in muscular tissue called a girdle. Some chitons, such as the Spiculed Chiton, have shells adorned with tiny spikes. Another species, the Snakeskin Chiton, has a scaly shell that resembles the skin of a serpent.

    Other Characteristics

    • Chitons range from 2 to 33 cm in length. For such a small organism, the chiton has a remarkably long lifespan of 20 years. The chiton has no truly developed head or tail. It also has no eyes, though light-sensitive organs in its girdle allow it to sense the level of light around it. Most of the underside of its body is taken up by a muscular foot, which it uses to propel itself forward.

    Habits

    • Chitons crawl across rocks using a single foot. They are prey for crabs and fish. When startled by a predator, a chiton clings to the surface it is on, presenting its armored shell to its attacker. Chitons eat by scraping algae and small worms from rocks with their radula, a long, tongue-like ribbon of teeth. When it comes time to breed, the female releases gametes into the water, which are then fertilized by a male.

    Types of Chitons

    • There are about 800 known types of chitons. The largest is the gumboot chiton, which grows to more than a foot in length. Due to its size, the amount of magnetite on its shell registers with metal detectors. The tiniest chiton is the lined chiton with zig-zagging lines on its shell. The colors of these lines range from rosy pink to reddish orange. The hairy chiton, with small hairs on its girdle, is another particularly distinctive species.