Biology/Natural History: An omnivore and scavenger, feeds mainly on surfgrass. Diet also includes echinoids, algae, sponges, bryozoans, and colonial tunicates, plus organic films on rocks. It cannot open clams. Feeds by everting its stomach, which it may even evert to gather particles from the water. Most animals which avoid other seastars have little response to this species, except for the nudibranch Dendronotus iris, which may swim away. Spawn at least from May to July but ripe individuals can be found throughout the year. Individuals may combat one another if they meet, including pushing, placing a ray over the opponent. May have several individuals of the commensal polychaete worm Ophiodromus pugettensis living on the oral surface or in the ambulacral grooves. This species is often used for developmental studies because ripe individuals can be found throughout the year.