Phylum: Mollusca
Class: Polyplacophora
Order: Neolocrcata
Family: Acanthochitonidae

Genus/species: Cryptochiton stelleri

GENERAL CHARACTERISTICS: The gumboot is a long, meatloaf-like chiton with a brick-red mantle covering the eight plates of their jointed shell. The shell plates are completely internal in adults. This is the largest chiton in the world; it grows to 33 cm (13 in). It may live up to 20 years.

Gumboot Chiton32905300616_5519787bf4_k

DISTRIBUTION/HABITAT: Found from Alaska west to Japan and south to the Channel Islands, the gumboot chiton inhabits rocky intertidal areas to 80 feet, often among kelp.

DIET IN THE WILD: A nocturnal grazer, it used its long, tongue like radula to scrape off the upper tissue of soft red algae and various coralline algae, giant kelp and oarweed, in the process getting nutrition from the tiny organisms that live on the algae’s surface. The radula is covered with tiny, very hard teeth that give it the texture of rough sandpaper.


PREDATORS: Its only known predator is the large rock snail Ocenebra lurida, which drills through the chiton’s outer covering with its radula to feed on the flesh below.

REPRODUCTION: The sexes are separate; eggs and sperm are broadcast into the sea.


REMARKS: California coastal Native Americans may have eaten them, as shell plates have been found in middens. An Academy researcher states that this chiton was a food of the last resort, “tastes ghastly!”

The radulae of chitons and limpets are unique in having a high percentage of iron magnetite incorporated into the feeding teeth. Magnetite is so named because it is strongly attracted to magnets, and you can actually pick up this chiton’s teeth and radula with a magnet!
When exposed to air during low tide, the gumboot chiton can breathe at a reduced rate by absorbing oxygen from the atmosphere.

The red fuzzy stuff often on the surface is red algae. About 20 species of red algae are known to live on subtidal individuals. This chiton’s diet of red algae also contributes to its color.

Chitons are among the most ancient living mollusk groups, dating back to 400–500 million years ago.


California Academy of Sciences Steinhart Aquarium Tidepool 2017

Monterey Bay Aquarium…



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