Chitons belong to the class Polyplacophora (bearing many plates), this class has over 500 living marine species in its order. They have 8 overlapping plates that make up their armor. The plates or valves as they are sometimes referred to as are joined by a leather-like girdle. This allows them to roll up into a ball when it is disturbed or threatened, hence their common name of butterfly shells.
Chitons (pronounced ky-tons) are very common on the shores of the Pacific Northwest. They are only found in the ocean, there are 500 to 600 species of chitons worldwide with over 100 found along the northwest coast of Canada and the US.
These animals have no eyes or tentacles but its shell contains some very sensitive organs that can perceive shades of light. Many of the species prefer low light and only come out of hiding at night, during the day, they hide under rocks or in crevasses with some even digging down into the sand to hide.
They move along with their large and muscular foot much like a snail does. They attach themselves to the rocks and then they follow the contours as they move along searching for food, they feed on algae and small animals with their radula or tongue. They do not move very fast and some chitons have been seen at the same site for more than 25 years.
The sexes are separate when mating, gametes are released into the water and fertilization then takes place. A few species will keep their eggs in a groove alongside the foot.
Two species were important food sources for the first peoples, the black Katy and the giant Pacific chitons were both heavily used as food, the ritual of gathering, cooking, and eating these animals was quite significant. There are many stories and legends about them that date back to times long gone.