Snails

Below are examples of snails you will likely run across if you spend any time on Oregon’s exposed shores. The photos are from northern Oregon unless noted, and my organization roughly follows Lamb and Hanby (2005). Common names are my choice. I refer to WoRMS for scientific names, and I learn a ton by browsing the natural history riches in Kozloff (1993). Biodiversity of the Central Coast’s Molluscs page contains excellent information about the species shown below. And they are covered in the books, field guides, and online resources listed at the bottom of the page.

Let the snails be upon you!

Nucella ostrina northern striped dogwinkle
Nucella ostrina is most noticeable among the acorn barnacles Balanus glandula. They’re easy to find (they’re shy but not secretive) and one of the rocky intertidal snails I most enjoy.

close up of 19 N. ostrina the navy from whit to dark gray with no pattern to brown with light and dark stripes
The color and pattern of Nucella ostrina shells are variable
Two smooth-shelled N. ostrina, one orange and one very pale
A smooth orange shell is eye-catching
Close up of a pale-purplish shell with darker purple strips and some shell erosion, this one perched high up among the acorn barnacles.
Color, pattern, and sculpturing combine to make a lovely shell
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Nucella canaliculata channeled dogwinkle

Their shell coloration is usually on the drab side
An aggregation on and around a mass of egg capsules
Nucella canaliculata and a favored prey, Mytilus spp.
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Lirabuccinum dirum dire whelk
I haven’t run across dire whelks on northern Oregon shores. Those shown below are from sheltered Salish Sea beaches.

Lirabuccinum dirum on the inside of a cockle shell (I turned over the shell to get this shot) | Galiano Island
L. dirum waiting out low tide | Galiano Island
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Nassarius fossatus channeled basket snail
Channeled nassas, as they are also known, apparently don’t overlap much with me in the northern Oregon intertidal. I don’t recall coming across a live one. Empty nassa shells, however, can be abundant, and hermit crabs frequently occupy them. Although I think the egg cases shown below are those of N. fossatus, I haven’t seen deposition, only drifted cases.

An empty shell up against a small piece of driftwood on small, wet gravel.
With natural polishing, empty Nassarius fossatus shells are beautiful | Central Oregon
About 30 drifted egg cases captured by a small anemone in a shallow, sand-filled pool.
Drifted egg cases are pretty common in pools and sea wrack | Central Oregon
Shell turned to reveal the opening, which is closed off by the pinching claw of the occupant, a hermit crab.
Hermit crabs prize empty Nassarius fossatus shells | Central Oregon
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Tegula funebralis black turban
Black turbans are conspicuous and abundant. They seem more numerous on the central coast than in most northern Oregon locations.

The top of the shell is almost always eroded
A variety of small invertebrates hitch-hike on Tegula shells
Not much black at all here | Central Oregon
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Callianax biplicata purple olive
On exposed beaches, up your odds of finding purple olives by walking out toward the swash on a pretty low tide. When things are just right, and I don’t know exactly what that looks like, they can be startlingly abundant. But you won’t find them on every stretch of the beach; maybe try a beach with large protruding boulders, stacks, or a contoured shoreline that gives a little shelter.

A lone snail on a journey over, and partially through, very wet (saturated) beach sand.
Callianax biplicata is at home on clean sandy beaches
Purple olive tracks in wet beach sand that resemble english letters G ad J
Purple olives have a lot to say, and they write it all down
A single snail emerging from its burrow. A strand of slime stretches from the burrow entrance to the snail (less than a cm).
Caught in the act of emerging
A single snail has left its burrow and is now moving over clean beach sand, barely leaving a trace.
Taking the surface route
Closeup, from above, on a single snail on clean wet sand.
Purple olive’s are lovely little snails


Below is a collection of traces left by purple olives. It’s worth knowing what you’re looking at so you don’t have to dig them up to find what made them.

Six dimples on clean sand. There's a purple olive beneath each one.
Shows
A trail in the sand that resembles the numeral six
Trail
A barely visible purple olive acting very much like a snowplow, plowing through wet sand.
Snowplow
A mounded tunnel created by a single olive burrowing just under the surface.
Tunnel
A dense collection of shows, plow tracks, and tunnels on clean wet sand.
Collection of traces
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References

Gotshall, D. W. 2005. Guide to Marine Invertebrates, Alaska to Baja California 2nd Edition (Revised). Shoreline Press.

Harbo, R. M. 2011. Whelks to Whales: Coastal Marine Life of the Pacific Northwest. 2nd ed. Harbour Publishing Co.

Kozloff, E. N. 1993. Seashore Life of the Northern Pacific Coast. 3rd ed. University of Washington Press.

Lamb, A. and B. P. Hanby. 2005. Marine Life of the Pacific Northwest. Harbour Publishing.

Sept. J. D. 2009. The Beachcomber’s Guide to Seashore Life in the Pacific Northwest. Revised ed. Harbour Publishing.


Online Resources

Charbonneau, N., Helmstetler, H., and Cowles, D. (2009). Nucella ostrina (Deshayes, 1839). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 09/15/2022.

Cowles, D. (2005). Nucella canaliculata (Duclos, 1832). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 09/15/2022.

Cowles, D. (2006). Nassarius fossatus (Gould, 1850). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 09/15/2022.

Cowles, D. (2004). Chlorostoma funebralis (A. Adams, 1855). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 09/15/2022.

Cowles, D. (2006). Callianax biplicata (Sowerby, 1825). Invertebrates of the Salish Sea. Rosario Beach Marine Laboratory. Accessed 09/15/2022.

Biodiversity of the Central Coast’s Molluscs page contains excellent information on most of the snails shown above.


I updated this page on September 15, 2022.