Tuesday, December 14, 2010

December 14, 2010 : Electric Catfish

Electric Catfish

Electric catfish is the common name for the catfish (order Siluriformes) family Malapteruridae. This family includes two genera, Malapterurus and Paradoxoglanis with 19 species. Several species of this family have the ability to produce an electric shock of up to 350 volts using electroplaques of an electric organ. Electric catfish are found in tropical Africa and the Nile River. Electric catfish are usually nocturnal and feed primarily on other fish, incapacitating their prey with electric discharges.

Malapteruridae is the only group of catfish with a well-developed electrogenic organ; however, electroreceptive systems are widespread in catfishes. The electrogenic organ is derived from anterior body musculature and lines the body cavity. Electric catfish do not have dorsal fins or fin spines. They have three pairs of barbels (the nasal pair is absent). The swim bladder with elongate posterior chambers, two chambers in Malapterrus and three in Paradoxoglanis.

The Nile fish was well known to the ancient Egyptians. The Egyptians have depicted the fish in their mural paintings and elsewhere; the first extant depiction of an electric catfish is that on the slate palette of the pre-dynastic Egyptian ruler Narmer, about 3100 BC. An account of its electric properties was given by an Arab physician of the 12th century; then as now the fish was known by the suggestive name of Raad or Raash, which means thunder (literally trembler, shaker).

Though the shock an electric catfish can generate is not known to be fatal to humans, the catfish does use its electricity as a weapon to ward off predators.

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