Snails

Below are a few examples of snails living on Oregon’s exposed rocky shores and, rarely, on the beaches. The photos are from northern Oregon unless noted. These are the easy-to-spot snails I’ve seen and photographed on the shores I’ve visited; they’re the ones you can find with a light touch without turning rocks or creating disturbances. Organization-wise, I loosely follow Lamb and Hanby (2005). If I use common names, they’re my choice. Experts cover these examples and many more in the books, field guides, and identification 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 and, without question, one of the rocky intertidal snails I most enjoy.

Color and pattern variation in several individuals on a bed of acorn barnacles.
The color, pattern, and sculpturing of Nucella ostrina shells are variable
Two smooth-shelled N. ostrina, one orange and one pale.
A smooth orange shell is eye-catching
A few Nucella ostrina around a small patch of egg capsules.
Vase-shaped egg capsules
Four Nucella ostrina around a small mass of clean, pale new egg capsules.
Capsules contain a few embryos and lots of nurse eggs
Closeup 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
***

I’ve always referred to the dogwinkles featured below as Nucella canaliculata, and that’s what you’ll see in most of the references at the bottom of this page, but knowledge is ever-changing. While there is more to learn about diversity in this group, as I now understand it, N. canaliculata is thought to range only as far south as Washington, meaning the similar-looking form from Oregon is Nucella analoga, previously included with N. canaliculata.

Close mid intertidal scene with six snails nestled in the corallines.
Nestled beautifully among the corallines
A mostly bare rock scene with three Nucella analoga (probably) and a rosette of young mussels.
I feel like those mussels are in danger
A little aggregation of Nucella analoga (probably) and Nucella ostrina. All the sails are pretty drab, but one of the N. analoga is bright orange.
An occasional burst of orange, Nucella style
Three Nucella species, some acorn barnacles, and a few small mussels share the top of a rock.
The not-too-uncommon but always delightful co-occurrence of three Nucella species
Shell coloration is usually muted or subdued; here, markedly drab

The shells’ ridges and the channels between them are a little variable and always captivating.

Three Nucella analoga (probably) on a background of barnacles.
A trio of dogwinkles on the central Oregon shore
A closeup of a lone snail on a background of barnacles.
Loner on a barnacle bed
In the foreground, several dogwinkles, in a stand of young Mytilus. Coastal slope in the background. Rain.
Among favored prey | Central Oregon

Dense aggregations occasionally materialize. The scenes below are from July.

Dense aggregation of dog winkles on a low rock surrounded by sand. Beach and some large protruding rocks in the background. Surf zone beyond. Cloudy sky.
Huddled on a low sand-scoured rock
Closeup on a dense aggregation of dogwinkles.
Quite a mob

Spring and early summer are favorable for finding clusters of flask-shaped egg capsules. Early development is completed inside the capsules and juveniles emerge as miniature snails.

A rock topped with dogwinkles, some egg masses clusters, and a starfish on one side. Surf size and beyond in the distance.
Piaster would like a word
Closeup on nine dogwinkles and a cluster of egg capsules on a bare rock (except for a crustose coralline in places).
An April laying
An assemblage of dogwinkles in and around a mass of egg capsules. Articulated corallines and giant green anemones are also present among the sand at the bottom of the scene.
An aggregation with egg capsules | June
***

Lirabuccinum dirum dire whelk
I haven’t run across dire whelks on northern Oregon shores. Those shown below are from sheltered 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
***

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
***

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
***

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 olives 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
***


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. 2019. The New Beachcomber’s Guide to the Pacific Northwest. Harbour Publishing.


Online Resources

Biodiversity of the Central Coast’s Molluscs page contains excellent information on most of the snails shown above. Accessed 02/28/2023.

Friends of Netarts Bay WEBS Mollusks page. Accessed 02/28/2023.

It’s worth scrolling down to Gastropoda in Common Sea Life of Southeastern Alaska: A field guide by Aaron Baldwin & Paul Norwood. Accessed 02/28/2023.


Bering, N., T. Hext and E. Parker. 2017. Nucella ostrina. In: Oregon Estuarine Invertebrates: Rudys’ Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biol- ogy, Charleston, OR.

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.


I updated this page on February 28, 2023.