Although referred to as a purple sea star, this specific species can be highly variable in color with the potential to be colored orange, yellow, red, or even shades of brown (1). The purple sea stars’ average arm radius averages to approximately 9 cm but in reality can reach up to three times that size with most individuals having 5 arms (1). While the common habitat remains the mid-to-lower rocky intertidal zone, the geographic range is from Alaska to Baja California, Mexico (1). The Pisaster ochraceus sea star is considered a keystone species with mussels as the main dietary content (1). To eat the mussels, the sea star will invert its own stomach and insert itself within the mussel to consume the prey (1).
(1) Pisaster | MARINe (n.d.). Retrieved from https://www.eeb.ucsc.edu/pacificrockyintertidal/target/target-species-pi...
(Photograph) Peter J. Bryant, University of California, Irvine