Oysters are an interesting part of the Mollusc tribe. They are bivalves, meaning that they have two half shells, which are jointed together on one edge and can open and close as the animal desires, or more properly, is instinctively demanded to do.
Unlike their cousins, clams, oysters are from infancy pretty much fastened onto some sort of support, so they do not move. Clams are sort of solitary, and like to dig into sandy beaches. Another relative, the scallop, is so free to move that jet propulsion is the norm for them!
Let us examine some of the natural history of these interesting (and often delicious) animals. We will point out that edible oysters are quite different from the pearl oysters.