From ArticleWorld

A clam is a freshwater or marine mollusk. There is no real scientific classification ‘’clam’’, but it is generally used to refer to any mollusk that is not an oyster, mussel, or scallop. Clams can live up to 150 years, and possible longer. Some quahogs found off the East Coast of the United States are believed to be 200 years old.

Clams may be hard or soft-shelled, and are served a variety of ways including raw, steamed, boiled, baked, fried, and in sauces or chowders.


  • The Arc clams - family Arcidae
  • The Hard clam or Northern Quahog – native to the eastern shore of North America
  • The Soft clam - often called steamers, softshells, or longnecks
  • The Surf clam - often served raw, or for use in chowders
  • The Ocean quahog - Arctica islandica
  • The Pacific razor clam – native to the Pacific West Coast
  • The Giant clam - can weigh more than 400 pounds
  • The Asian or Asiatic clam - genus Corbicula
  • The Peppery furrow shell - commonly found in northern Europe, the Mediterranean, and West Africa
  • The Pismo clam - Tivela stultorum
  • The Geoduck clam – largest burrowing clam in the world

Shells and pearls

Many animals, particularly those that live in the sea, produce exoskeletons. Usually only those of clams, and other mollusks, are considered to be shells. When a mollusk is invaded by a parasite, or foreign object that the animal cannot eject, a process known as encystation encases the entity in successive, layers of mother-of-pearl. This process eventually forms a pearl, and will continue for as long as the mollusk lives.