Despite having lived near the Oregon Coast I’ve never learned much about the ocean and the creatures that live in it.
Sure, I love walking down the beach but, whenever my parents visit it’s like they expect me to have achieved marine biologist status just by proximity to the ocean.
Or at least I didn’t. I decided to put in the work I should have put in years ago and learn more about the Oregon Coast, starting with the types of shells I’m likely to find on the beaches here.
Luckily, the types of seashells found on Oregon Beaches are pretty easy to classify as the wildlife here, while diverse, is not nearly as varied as it would be in a more tropical location.
So whether you want to impress yourself or your kids, let’s talk about the basics for identifying the seashells you’ll find on the Oregon Coast!
I’m not yet adept enough to teach you all the species and exact types but we’ll get the gist of it!
The 3 Types Of Shells You’ll Find On Oregon Beaches
Pretty much every shell you find on Oregon beaches (or any beach for that matter) will be from a creature from the phylum Mollusca. For all intents and purposes, they are the only shell makers.
Now, there are two families in the phylum which will give us all the shells that are common on Oregon beaches: Gastropoda (which encompasses snails, and limpets) and Bivalvia (encompassing clams, mussels, etc.)
You should be able to tell relatively quickly what kind of shell you’re looking at once you have a few basics so let’s take a look at the bivalves and gastropods and see what you’re looking at.
While you might not be able to tell the species without some further study, we’ll at least be able to tell our kids (or spouse) whether it’s a snail shell, clamshell, etc.
So let’s take a look at a few examples of each one so you can easily figure out what you’re looking at on the beach.
Limpets are a type of small, marine snail that belongs to the Gastropod family. These creatures are found in oceans all over the world, and they come in a variety of shapes and sizes. The most distinguishing feature of a limpet is its conical shell, which is used for protection from predators and the environment. Limpets are also equipped with a strong foot that helps them attach themselves to rocks and other surfaces.
In addition, limpets have a simple digestive system and a colorful mantle (the tissue that covers their internal organs). Although they are often considered to be pests, limpets play an important role in the marine ecosystem by grazing on algae and other aquatic plants.
Limpet shells are easy to identify and differentiate from bivalves such as clams.
Known colloquially as a “Chinese hat” limpet shells have a high point in the middle of the shell like a little pyramid. Many of them have a visible hole in the top of the shell.
They also have no hinge as they are only a top shell.
It’s worth noting that species of limpets can vary significantly based on what “form” you’re looking at. For example, a single species (such as a Shield Limpet) can have different coloring and shape depending on its habitat. The Shield Limpet has a rock form, a mussel form, and several kelp forms. However, all are recognizable as a limpet.
Limpet Species of Oregon
- Whitecap Limpet
- Ringed Blind Limpet
- Giant Owl Limpet
- Shield Limpet
- Ribbed Limpet
- Rough Limpet
- Black Limpet
- Fenestrate Limpet
- Pacific Plate Limpet
- Seaweed Limpet
- Unstable Limpet
A bivalve is a type of mollusk that has two hinged shells connected by a strong ligament. This allows them to open and close their shells to protect themselves from predators or to filter food from the water. Bivalves can be found in all sorts of habitats, from freshwater lakes to the deep sea, and are commonly seen in tidepools or on Oregon beaches.
When you think of bivalves, think of the common ones that you see in the grocery store such as mussels, scallops, clams, and oysters.
Bivalves shells are particularly interesting because they can tell us a lot about past climates and environments. By studying the growth rings on a bivalve’s shell, scientists can learn about changes in temperature, salinity, and other environmental factors over time.
Mussel vs. Clam vs. Oyster vs Scallop Shells
You’ll find a huge variety of bivalve shells on Oregon beaches so let’s take a look at how you can figure out which is which.
However, all the shells look similar enough that you’ll be able to roughly identify them.
Nearly every shell that’s leftover at this point is from some sort of gastropod, a snail. Even shells that you find hermit crabs living in are leftovers from some sort of snail.
Now, there are six kinds of snail shells you’ll find on Oregon beaches that have distinct shapes: Slippersnails, Topsnails, Turbansnails, Periwinkles, Bubblesnails, and Wentletraps.
Luckily for us, they’re super easy to tell apart and a single picture will probably give you all the information you need. So here it is:
Beyond those, you’ll also find the shells of Hairysnails, Hoofsnails, Dogwinkles, Nassas, and Whelks but they’re all similar enough that you should be able to point them and say, “That’s a snail shell!”
The Formation Of Seashells
They all look similar (especially when worn by the surf) because, really, all seashells are pretty much the same thing in a slightly different shape. That is, in the same way that all trees are made out of wood.
Seashells are obviously not made of wood. They are made from a substance called calcium carbonate. This substance is found in abundance in seawater and is also a main component of sand. When creatures such as oysters and clams filter seawater for food, they also ingest calcium carbonate.
These creatures then secrete a substance called ‘nacre’ which coats the calcium carbonate particles and glues them together. Layer upon layer of nacre is secreted until a thick shell is formed. The color of the nacre and the final shell depends on the type of creature that secreted it.
However, it’s not unusual to find similar patterns and colorations between animals in an area as natural selection has favored shells that have more protective colorings and shapes for a specific ecosystem.
The shells of the PNW are rarely bright as those in tropical areas might be as they need to blend into the brown rocky beaches of Oregon.
In addition to the shells above you may also find things on the beach that are more unusual and hard to identify.
If the item you find isn’t trash or a rock, here are a few other things it might be:
- sand flea or crab shells (not a lobster though…)
- sea urchin tests
- sea glass
- weathered aluminum
- sea star pieces
I’m sure there are more things among the shells of Oregon beaches but just the information here will put you head and shoulders above nearly everyone else that visits the coast!
Happy beach combing!