Cryptochiton stelleriGiant Pacific Chiton

Geographic Range

Alaska to Channel Islands, California to Japan


Among rocks, near low-tide level to water 60' (18 m) deep. May be found in shallow waters during spawning season in May.

Physical Description

Commonly called the gumboot "chiton," Cryptochiton stelleri is the world's largest chiton species, reaching a length of 14 inches.


Separate sexes; males deposit sperm into water and females lay eggs in strings, clusters or spiral arrangements. Eggs may be free-floating single cells or enclosed in jelly-like capsules or strings.


Usually nocturnal, browse surface of intertidal rocks for food. They also have an amazing ablility to cling to rocks.

Food Habits

Feeds on various fleshy and coraline algae such as sea lettuce, also on bryzoans and diatoms.

Economic Importance for Humans: Positive

Some species of chitons are often found in Indian and West Indian foods, and they are used as bait.

Conservation Status


  • IUCN Red List [Link]
    Not Evaluated

Other Comments

There are over 600 species of chitons, and one of the most diverse groups is found on the Pacific Coast. To keep its surface clean of other organisms, a chiton secretes a mucus that swells on contact with water. This touh mantle completely covers the chiton's eight transverse shell plates, and prevents foreign organisms from attaching to the spines of the girdle.


Almaz Kinder (author), University of Michigan-Ann Arbor.


Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


the nearshore aquatic habitats near a coast, or shoreline.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.


found in the oriental region of the world. In other words, India and southeast Asia.

World Map


Abbott, R.T. 1954. American Seashells. D. Van Nostrand Co., Inc.

Abbott, R.T. 1986. A Guide to Field Identification: Seashells of North America. Golden Press, New York.

Cernohursky, W.O. 1967. Marine Shells of the Pacific. Pacific Publications.

Morris, P.A. 1966. A Field Guide to Shells of the Pacific Coast and Hawaii. Houghton Mifflin Company,Boston.

Rehder, H.A.1994. National Audobon Society Field Guide to North American Seashells. Chanticleer Press, Inc., New York.

Rogers, J.E. 1908. The Shell Book. Charles T. Branford Co., Publishers, Boston.

Sabelli, B. 1979. Simon & Shuster's Guide to Shells. Simon & Shuster, Inc.