
Littleneck clams; the pictured molluscs are of the species ''Mercenaria mercenaria''.
A 'clam' is a type of
mollusk. Clams are invertebrates with shells divided into two pieces called valves. While the term "clam" has no
taxonomic significance in
biology, it usually refers to either a bivalve (a mollusk whose body is protected by two symmetrical shells) that is not an
oyster,
mussel, or
scallop, and that has a more-or-less oval shape, or to a freshwater mussel (
Merriam-Webster Dictionary ). An exception to the oval shape is the
razor clam, which has an elongated shell whose shape suggests a
straight razor. The clam's two shells are connected by a hinge joint. Two adductor muscles open and close the shells. The clam has no
brain or
eyes, but it does have
kidneys, a
heart, a
mouth, and an
anus. Clams, like most mollusks, also have
open circulatory systems, which means that their organs are surrounded by watery blood that contains nutrients and oxygen. Clams eat plankton, and they themselves are eaten by small sharks and squid.
In culinary use, the term "clam" most often refers to the
hard clam (Taxonomically, ''Mercenaria mercenaria'') but may refer to other species such as the
soft-shell clam ''Mya arenaria''. They are eaten raw, steamed, boiled, baked or
fried; the method of preparation depends partly on size and species.
Clam chowder is a popular soup in the
U.S. and
Canada. In Italy, they are often an ingredient of mixed seafood dishes, or are eaten together with
pasta. Saltwater Maxima clams are also somewhat popular in the hobby of fish-keeping. Clams travel by pushing off with a muscular foot-like structure. They also contain little toes that are used in reproduction.
The
Moche people of ancient
Peru worshipped the sea and its animals. They often depicted clams in their art.
[1]
Examples of clams
★ The
ark clams, family Arcidae
★ The
nut clams, family
Nuculidae
★ The
pointed nut clams, family Nuculanidae
★ The
duck clams or
trough shells, family
Mactridae
★ The
marsh clams, family Corbiculidaess
★ The
file clams, family Limidae
★ The
hard clam or Northern
Quahog: ''Mercenaria mercenaria''
★ The
Soft clam: ''Mya arenaria''
★ The
surf clam: ''Spisula solidissima''
★ The
ocean quahog: ''Arctica islandica''
★ The
Pacific razor clam: ''Siliqua patula''
★ The
giant clam: ''Tridacna gigas''
★
Chink or Asiatic clam: genus ''Corbicula''
★
Peppery furrow shell: ''Scrobicularia plana''
★
Pismo clam: ''Tivela stultorum'' (8 inch shell on display in the Pismo Beach Chamber of Commerce)
★
Geoduck clam: ''Panopea abrupta'' or ''Panope generosa'' (largest burrowing clam in the world)
★ The
Atlantic jackknife clam: ''Ensis directus
See also
★
Clam bake
★
Clam boil
References
1. Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera.'' New York: Thames and Hudson, 1997.