The two shells are held tightly closed by two internal abductor muscles. When the clam wants to move, the clam opens it shell by relaxing the abductor muscles and stretches out a hatchet-shaped foot. This foot grips the mud and allows the clam to pull the shell forward. This is how the clam moves along the bottom of the pond or stream. Clams gather food using a filtering system.
Water is taken in through an opening called a siphon.
As the water passes through, tiny plant and animal material is captured. It is then moved into the stomach for digestion. Clams also have a series of gills that remove oxygen from the water as it flows through its body. One of the most interesting things about clams is their reproductive cycle. These larvae are called glochidia and are released to the bottom of the pond.