Periwinkle Snail
Scientific Name: Littorina littorea
Category: shell
Brief Description
A small, spiraled sea snail commonly found in the intertidal zone of rocky shorelines.
Characteristics
Small, sturdy, conical shell with a rounded aperture and a dark, operculum (trapdoor). Surfaces are often grey, black, or brown and may be smooth or slightly ribbed.
Habitat
Rocky shores, tide pools, and salt marshes within the intertidal zone.
When to Find It
Year-round, most easily observed during low tide when they are exposed on rocks.
Conservation Status
Common / Least Concern
Ecological Role
They are primary grazers that control algae growth on rocks and serve as a vital food source for crabs and shorebirds.
Easily Confused With
Dog whelks (which have a more pointed shell and are predatory) and Mud snails (which prefer soft sediment over rocks).
Observation Tips
Look for them clustered in crevices or under seaweed during low tide to avoid desiccation. Always handle gently and return to the same spot.
Interesting Facts
Periwinkles can survive out of water for several days by sealing themselves inside their shells with a mucus-like glue and their operculum to retain moisture.