Explore your sweet (or bitter) side this Valentine’s Day with the western bittersweet

Ah, Valentine’s Day — no other holiday has the power to conjure up feelings of eager anticipation in some, and anxious dread in others. Love can bring both joy and pain into the lives of those who experience it, so what better critter to represent the most complicated of emotions than the western bittersweet?

What’s in a name?

Sometimes referred to as the button shell, the Pacific coast bittersweet, the northern bittersweet, and the California bittersweet, this little clam goes by many names. The genus name Glycymeris comes from the ancient Greek words for sweet (glykys) and part (meris), describing the sweet and nutty flavor of this bivalve group. Although the western bittersweet is not a commercial favorite in its native range of Alaska to California, you may find its relative, Glycymeris glycymeris, on the menu in Europe, where it is known as the dog cockle or sea almond. Sounds like a food you could either love or hate!

Bare your teeth

The western bittersweet belongs to the family Glycymerididae, one of the few families in Puget Sound which have taxodont dentition. This means that it has interlocking teeth on the inside of its shell around the hinge where the two valves meet. This feature is useful in telling it apart from the similar-looking Pacific littleneck clam, Leukoma staminea, which is similar in shape and also has radial ribs running down its shell.

The habitat of the bittersweet is also a giveaway — the littleneck lives intertidally, while the bittersweet finds subtidal conditions more to its liking. It buries itself on sandy or gravelly bottoms, happy to stay in one place until its light-sensitive eyespots detect potential danger. Then it uses its muscular foot to push itself to a safe location. Bittersweets are uncommon in Puget Sound, but we have collected a few of them from Pt. Townsend, Mutiny Bay, Dyes Inlet, and Oakland Bay, in depths up to 95 meters.

Beauty fades

Although true beauty comes from within, some western bittersweets are striking on the outside too, with variable brown-and-white zig-zag patterns on their thick, rounded shells. Others are a more drab solid brown or white. All start out with a dark brown layer of protein called the periostracum protecting the growing edge of the shell, kind of like a furry beard.

Eventually the slow hand of time fades the bright colors, wears off the periostracum, and files down the ribs of the shells until they are almost smooth in appearance — wrinkles in reverse! Far from detracting from their beauty, these marks of long lives well-lived in Puget Sound are a sweet thing indeed.

Critter of the Month

Our benthic taxonomists, Dany and Angela, are scientists who identify and count the benthic (sediment-dwelling) organisms in our samples as part of our Marine Sediment Monitoring Program. We track the numbers and types of species we see in order to understand the health of Puget Sound and detect changes over time.

Dany and Angela share their discoveries by bringing us a Benthic Critter of the Month. These posts will give you a peek into the life of Puget Sound’s least-known inhabitants. We’ll share details on identification, habitat, life history, and the role each critter plays in the sediment community. Can't get enough benthos? See photos from our Eyes Under Puget Sound collection on Flickr.