Biology/Natural History: Feeds on a variety of animals--bivalves, limpets, snails, brachiopods, barnacles, and tunicates. Can evert its stomach (up to a distance equal to half the length of a ray). Several limpets exhibit escape responses from this species. May have a symbiotic scaleworm (Arctonoe fragilis) living in the ambulacral groove or on the body surface (photo). In Alaska one can often find the young of the Alaska King Crab (Paralithodes camtschaticus) nestled between the rays of this seastar. Predators include gulls (especially in Alaska where they are common intertidally), Solaster dawsoni,and Pycnopodia helianthoides; and attacks by the rose star Crossaster papposus and by Alaska King Crab Paralithodes camtschaticus have been observed. Tolerant of reduced salinities down to 20 ppt.