algae and diatoms
to 1.2 inches (30 mm)
abalones, turban snails, jeweled top snails, periwinkles; Family: Acaridae
Oregon to southern Baja California
Rough limpets sport bowl-shaped, heavily ribbed shells in brown or gray. Over time, using the scalloped edges of their shells, rough limpets grind grooves in rocks until their shells fit perfectly. These custom-made "homesites" are covered by water only during spring tides and/or when the surf is high. At other times, spray from strong waves reaches the limpets, but doesn't cover them.
When the rocks are wet, limpets move about, grazing on diatoms (microscopic plants) layered on the rocky surfaces. When the rocks are dry, limpets must take action to conserve moisture. They return to their homesites, where they snuggle in by clinging tightly with their muscular feet.
While walking along a rocky shore, please don't disturb limpets you might see tightly tucked into their "homesites." They need to stay moist.
Oil from urban runoff or offshore oil spills could cover the grazing areas of the limpets. Proper disposal of motor oil, contaminants and harmful chemicals will help protect the well-being of limpets and other sea creatures.
Rough limpets and their close relative, ribbed limpets, live in harmony in the splash zone—one lives on vertical rock faces, and the other lives on horizontal rock faces.
A limpet rasps diatoms from rocks using a radula—a tonguelike band of tiny teeth that contain iron particles.