“Clam” is an informal name that refers to bivalves (such as oysters, scallops, mussels, cockles, clams, and numerous other families that can live in both fresh and saltwater environments. Most are filter feeders and have a shell consisting of two calcareous halves attached via a flexible ligament along a hinge line. Most are sedentary but some bivalves, such as scallops, are able to “swim” by opening and closing their valves rapidly. There are around 9200 named species of living bivalves and accompanying such a large number is an amazing diversity of forms, behavior, and other adaptations. Bivalves have historically been a very important part of the diet of coastal human populations.