They're smaller than cockles, which they resemble, and their color ranges from ivory to charcoal gray. Ridges in the littleneck's shell are narrow and crosshatched by concentric ridges absent in the cockle's. Butter clams reside in sandy mud and gravel, from six to 12 inches below the surface. They grow to four inches and have thick, chalky shells and short necks. The most popular bay clam is the gaper, locally known as the empire clam, presumably after the Empire district of Coos Bay, where the clam flourishes in nearby mudflats.
Diggers look for round or slightly oval holes in the mud, about an inch or so across.
There's no mistaking the gaper's presence when you poke a finger in the hole and feel it's rubbery neck retreat. Average gapers will be four to five inches long, with the largest exceeding seven inches and residing two feet deep or more. It takes effort to dig big ones out, but it's work well rewarded. Oregon's abundant and widely distributed soft-shell clams thrive in virtually every estuary. Although large specimens resemble and are sometimes confused with gaper clams, they have thinner and brittler elongate shells and shorter necks.