Hairy Chiton (Mopalia ciliata)

Description: Hairy chitons have a very similar appearance to mossy chitons (Mopalia mucosa). They can grow up to 7.5 cm long, have eight distinctive plates with a fuzzy girdle around the edge of their oval bodies. Hairy chitons can be distinguished from mossy chitons by the hairs on their girdle and their colors. Coming in a broad range of shades, the hairy chiton can have an orange, green, white, or gray tinted plates and mantle. The hairs on a hairy chiton’s mantel is typically thinner compared to a mossy chiton. Algae growing on the back of the chitons may make it hard to distinguish species by color. They best way is to feel the hairs on the mantle - soft means hairy chiton, rough/coarse means mossy chiton.

Habitat: The hairy chiton ranges from the Aleutian Islands, Alaska to Baja California, Mexico. They prefer mid to low intertidal rocky environments.

Diet: Like other species of chiton, hairy chitons scrape algae off the rocks where they live. They are also known to eat hydroids, sponges, and bryozoans.

Tide Pool Tidbits:

• At just 16 days old a hairy chiton will resemble a tiny version of an adult.

• The underside of a hairy chiton’s plates often have a pink and/or blue color to them.

• Hairy chitons are generally nocturnal grazers but they will occasionally feed on days when it is overcast.

Reference: Walla Walla University