Northern elephant seals exhibit extreme sexual dimorphism in their feeding behaviours. When the males leave their rookeries, they migrate northwards to their feeding grounds along the continental shelf from Washington to the western Aleutians in Alaska. The males mostly feed on benthic organisms on the ocean floor. When the females leave their rookeries, they head north or west into open ocean, and forage across a large area in the northeastern Pacific. They have been recorded as far west as Hawaii. Female elephant seals feed mainly on pelagic organisms in the water column.