Leather Chiton (Katharina tunicata)

Description: Leather chitons look like a black leathery oval with eight white diamond shaped plates running down their back. They have the same shaped plates as other chitons but with the large girdle covering most of the plates, the diamond shapes are all that’s visible. Algae sometimes grows on the exposed diamonds giving them more of a green color. One of the larger chitons found at Haystack Rock, they can be up to 15 cm long.

Habitat: Ranging from Alaska to southern California, the leather chiton lives in mid intertidal to subtidal zones. It can also be found in Siberia! At Haystack Rock, leather chitons are often found on the western part of the north wall or on large boulders in front of The Needles.

Diet: The leather chiton eats brown and red algae.

Tide Pool Tidbits:

• Leather chitons are a traditional food for many Indigenous peoples in the Pacific Northwest.

• These large chitons only live to 3 years old.

• This species is also frequently called the black Katy chiton, for its genus Katharina. In Alaska, they call this species the bidarki (pronounced bid-ark-ee).

References: The New Beachcomber’s Guide to the Pacific Northwest by J Duane Sept, Animal Diversity Web