Snails are abundant in the intertidal zone. Varieties include black and brown turban snails and periwinkles. At low tide some nestle tightly in crevices. Most snails graze on algae, scraping them off the rock with a rough, tongue-like radula. 

Snails can withdraw into their shells, behind a trapdoor-like bony plate called an operculum. This protects them from predators and water loss. Some exude mucus that coats their shells and helps them stick to the rocks and hold in precious moisture.