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Chitons: Polyplacophora

Behavior And Reproduction

Most chitons feed by scraping food off rocks with their radula. Others eat large species of algae, such as kelp. Predatory species use a special flap on the mantle near their head to capture small animals. Most species usually feed at night. Species living along the shore remain in one place when exposed to the air by low tides.

Chitons have few defenses. If pulled off their rocks, some species will roll up like a pillbug. This motion also helps them to right themselves. Some species will return to the same spot on a rock after they forage for food, while others continue to move on as they feed.


Roughly half of the approximately one thousand species of chitons live near coastlines. And, more kinds of chitons live along the eastern shores of the Pacific Ocean than anywhere else. About one-fifth of all the world's species live on or near the coastline that runs from Alaska south to Southern California.

Both male and female chitons are usually required for reproduction. Males always release their sperm into the sea. The sperm is carried on the ocean currents to the eggs. Depending on the species, females either release their eggs singly or in strings into the water or keep them inside the special groove that separates the girdle and muscular foot. Eggs fertilized in the water usually develop into free-swimming, unsegmented larvae (LAR-vee) covered with tiny, hair-like structures called cilia (SIH-lee-uh). Eggs that develop inside the groove remain with the adult female until they become well-developed young chitons.

Additional topics

Animal Life ResourceMollusks, Crustaceans, and Related SpeciesChitons: Polyplacophora - Physical Characteristics, Behavior And Reproduction, Gumboot Chiton (cryptochiton Stelleri): Species Accounts, Veiled Chiton (placiphorella Velata): Species Accounts - GEOGRAPHIC RANGE, HABITAT, DIET, CHITONS AND PEOPLE, CONSERVA