A major predator of barnacles and mussels in the mid-intertidal is the carnivorous snail, Nucella lapillus, commonly known as the dogwhelk. The dogwhelk is limited to the mid and lower intertidal areas preferring areas where they can stay cool, moist, and protected from wave action which can knock them loose. So you would expect to find them in cracks, crevices, and in the shade provided by seaweed canopies. For a lesson in anatomy click on the image to the left. In the above right image, look for two holes in the mussel shells. Can you guess what made these holes? Dogwhelks have an unusual way of eating...