They mostly eat crabs, shrimp, abalone, fish, and shellfish like scallops, clams, and mussels. In aquariums, they have been seen eating spiny dogfish ("Squalus acanthias"), a type of shark 3-4 feet long. Food is grabbed with its sucy rs and then crushed using its tough beak of chitin. North Pacific giant octopus are eaten by harbor seals, sea otters, and sperm whales. They usually live about 3-5 years in the wild. 