Sleeper shark

The Somniosidae are a family of sharks in the order Squaliformes, commonly known as sleeper sharks. The common name ''"sleeper shark"'' comes from their slow swimming, low activity level, and perceived non-aggressive nature.

Distribution and habitat

The Somniosidae can be found in:
*Arctic to subantarctic waters
*Shelves in cold waters
*Continental and slopes
*Temperate and tropical waters

Diet

Beaks recovered from the stomachs of sleeper sharks suggest they feed on colossal squid.Cherel, Y. & G. Duhamel 2004.   ''Deep-Sea Research Part I'' 51: 17–31.

Genera and species

* ''Centroscymnus'' Barbosa du Bocage & Brito Capello, 1864
** ''Centroscymnus coelolepis'' Barbosa du Bocage & Brito Capello, 1864 (Portuguese dogfish)
** ''Centroscymnus owstonii'' Garman, 1906 (roughskin dogfish)
* ''Centroselachus'' Garman, 1913
** ''Centroselachus crepidater'' Barbosa du Bocage & Brito Capello, 1864 (longnose velvet dogfish)
* '' Scymnodalatias'' Garrick, 1956
** ''Scymnodalatias albicauda'' Taniuchi & Garrick, 1986 (whitetail dogfish)
** ''Scymnodalatias garricki'' Kukuyev & Konovalenko, 1988 (Azores dogfish)
** ''Scymnodalatias oligodon'' Kukuyev & Konovalenko, 1988 (sparsetooth dogfish)
** ''Scymnodalatias sherwoodi'' Archey, 1921 (Sherwood dogfish)
* ''Scymnodon'' Barbosa du Bocage & Brito Capello, 1864
** '' Scymnodon ichiharai'' Yano & S. Tanaka (II), 1984 (Japanese velvet dogfish)
** '' Scymnodon macracanthus'' Regan, 1906 (largespine velvet dogfish)
** '' Scymnodon plunketi'' Waite, 1910 (Plunket's shark)
** '' Scymnodon ringens'' Barbosa du Bocage & Brito Capello, 1864 (knifetooth dogfish)
* ''Somniosus'' Lesueur, 1818
** ''Somniosus antarcticus'' Whitley, 1939 (southern sleeper shark)
** '' Somniosus longus'' Tanaka, 1912 (frog shark)
** ''Somniosus microcephalus'' Bloch & J. G. Schneider, 1801 (Greenland shark)
** '' Somniosus pacificus'' Bigelow & Schroeder, 1944 (Pacific sleeper shark)
** '' Somniosus rostratus'' Risso, 1827 (little sleeper shark)
** ''Somniosus'' sp. A Not yet described (longnose sleeper shark)
* '' Zameus'' D. S. Jordan & Fowler, 1903
** '' Zameus squamulosus'' Günther, 1877 (velvet dogfish)

Image:Centroscymnus crepidater.jpg, '' Centroscymnus crepidater''
Image:Scymnodon obscurus.jpg, '' Scymnodon obscurus''
Image:Zameus squamulosus.jpg, '' Zameus squamulosus''

Hákarl

Greenland sharks of the family Somniosidae are hunted for food in Iceland. In modern times, many Greenlandic sharks used for hákarl production are purchased from fishing ships where the sharks were trapped in the fishing nets. The shark carcass is traditionally fermented in a shallow pit, with stones placed on top of the shark, allowing poisonous internal fluids, like urea and trimethylamine oxide, to be pressed and drained out of the body. The meat is then cured for several months, rendering it safe for human consumption.

References

{{Authority control

Shark families
Taxa named by David Starr Jordan