The gumboot chiton, also known as the giant pacific chiton, is the largest of the chitons, growing to 13 inches. It is found along the shores of the northern Pacific Ocean from Central California and southwest to Japan. It inhabits the lower intertidal and subtidal zones of rocky coastlines. The name gumboot chiton derives from a resemblance to part of a rubber Wellington boot. These boots were previously known as gumboots.
Chitons are mollusks which have eight armored plates running in a flexible line down their back. Unlike most chitons, the gumboot’s valves are completely hidden by its leathery upper skin, which is usually reddish brown in color or occasionally orange. The gumboot can live for 20 years. It has few natural predators, the most common being the lurid rocksnail.
The gumboot chiton’s underside is orange or yellow and consists mostly of a large foot similar to that of other mollusks like snails or slugs, with gills found in grooves running along the outer edge of the foot. It is found clinging to rocks, moving slowly in search of its diet of algae, scraped off of rocks with its rasp-like retractable radula, covered with rows of magnetite tipped teeth. It also eats other marine vegetation such as sea lettuce and giant kelp. A nocturnal creature, the gumboot generally feeds at night and often remains in a hiding place during the day, although on foggy days it may be found exposed in tide pools or on rocks.
Its flesh is edible, and has been used as a food source by Native Americans, as well as by Russian settlers in Southeast Alaska. However, it is not generally considered palatable, with a texture described as extremely tough and rubbery. The writers of Between Pacific Tides further detail the culinary drawbacks 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 chiton, and it radiated such a penetrating fishy odor that it was discarded before it reached the frying pan.”
The gumboot chiton’s bony armoring plates, called butterfly shells due to their shape, can sometimes be found washed up on beaches, as can whole chitons. The gumboot keeps a weaker grip on the rocks that make up its home than most chitons do, and therefore it is not unusual for them to be knocked loose in heavy waves.