Ochre seastars (Pisaster ochraceus) feed on invertebrates, such as coral and shellfish, like the mussels pictured here. The starfish forces open the shell with suction disks on the underside of its body, and then inserts its stomach membranes through its mouth into the opening of the shell. Digestive juices break down the shellfish's body, which is then absorbed into the starfish's stomach.