Snails Sea Slugs and Limpets: Gastropoda

Physical characteristics: The surface of the hatlike shell has fine growth rings and ribs radiating out from the center like spokes on a wheel, with a high point slightly toward the front. The color varies from blue black to light brown, with or without white markings. Adult shells reach up to 2.3 inches (60 millimeters) across.

Geographic range: They are found in the Northern Pacific Ocean, from Honshu, Japan, across to Baja California, Mexico.

Habitat: They live along rocky coastlines, in the middle of the area affected by high and low tides.

Diet: Shiled limpets eat a variety of kinds of algae.

Behavior and reproduction: This species is active at night. The color and surface texture of individual shells gradually change as the limpet moves onto different surfaces.

The color and surface texture of individual shells gradually change as the limpet moves onto different surfaces. (Illustration by Emily Damstra. Reproduced by permission.)

Males and females larger than 0.39 inches (10 millimeters) reproduce in spring. Smaller individuals, as well as those living in the water just beyond the tide action, reproduce throughout the year. Eggs and sperm are released into the water where fertilization takes place.

Shield limpets and people: This species was once an important food source for ancient peoples living along the coast.

Conservation status: Shield limpets are not considered threatened or endangered. ∎