Cryptochiton stelleri, (Middendorff, 1847)
The gumboot chiton (Cryptochiton stelleri), also known as the giant western fiery chiton or giant Pacific chiton, is the largest of the chitons, growing to 36 cm (14 in) and capable of reaching a weight of more than 2 kg (4.4 lb). It is found along the shores of the northern Pacific Ocean from Central California to Alaska, across the Aleutian Islands to the Kamchatka Peninsula and south to Japan. It inhabits the lower intertidal and subtidal zones of rocky coastlines. The gumboot chiton's appearance has led some tidepoolers to refer to it, fondly, as the "wandering meatloaf". The name "gumboot chiton" seems to derive from a resemblance to part of a rubber Wellington boot or "gum rubber" boot.
Chitons are molluscs that have eight armored plates (called valves) running in a flexible line down their back. Unlike most chitons, the gumboot's valves are completely hidden by its leathery upper skin or girdle that usually is reddish-brown or brown, but occasionally is orange in color.
Chitons have long arrays of fine teeth that are partially made of magnetite, making its teeth hard enough to scrape algae off rocks. The styli enclosing their teeth contain the mineral santabarbaraite, making the gumboot the first organism known to use this material.
It has few natural predators, the most common being the lurid rocksnail, Paciocinebrina lurida—although the small snail's efforts to consume the chiton generally are limited to the outer mantle only. Sometimes it is reported that the lurid rocksnail is the gumboot chiton's only predator, but others list such animals as the sea star Pisaster ochraceus, some octopus species, and the sea otter as predators upon the gumboot.
Its flesh is edible and has been used as food by Native Americans, as well as by Russian settlers in Southeast Alaska. However, it generally is not considered palatable, having a texture described as extremely tough and rubbery.
The writers of Between Pacific Tides detailed their culinary assessment of the gumboot: "After one experiment the writers decided to reserve the animals for times of famine; one tough, paper-thin steak was all that could be obtained from a large cryptochiton, and it radiated such a penetrating fishy odor that it was discarded before it reached the frying pan."
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