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  • California Horn Snail


    The California horn snail lives in salt pans that only fill with water at high tide and is adapted to withstand high temperatures and strong salinities. It adapts to changing tidal conditions by retreating into its shell and shutting its “door” or operculum with mucus, and waiting for the next high tide.

California horn snail


California Horn Snail

California Horn Snail, by flickr user stonebird

California horn snail

Although tidal mudflats appear to be bare, they actually support a large community of shellfish, snails, and other invertebrates which are extremely important for wintering waterfowl and shorebirds.

One such invertebrate that lives in the tidal mudflats is the California horn snail (Cerithidea californica), found from Central Baja to Bolinas Bay. It eats decaying plants and algae and benthic diatoms (a one-celled form of algae that lives at lower depths of the water).

Biologists are very interested in the California horn snail because it may be an indicator of the marsh community. The California horn snail is a host for parasitic worms called trematodes. These worms start their life cycle in a snail and eventually end up in birds, without causing harm to the birds. Since trematodes have a complex life cycle, it is a good indicator that predator-prey relationships are working. Biologists studying a marsh in Santa Barbara found that the more birds found at a site, the more trematodes were also found. The California horn snail hosts more than 20 trematode species, making it a species that wetland managers may be able to use for restoration decisions.

Sources/Further Reading

US Geological Survey Monthly Newsletter, July 2006