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Pitvipers

Pit Viper
Crotalus horridus (1).jpg
Timber rattlesnake, Crotalus horridus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Viperidae
Subfamily: Crotalinae
Oppel, 1811
Synonyms
  • Crotalini Oppel, 1811
  • Crotales Cuvier, 1817
  • Crotalidae Gay, 1825
  • Crotaloidae Fitzinger, 1826
  • Cophiadae Boie, 1827
  • Crotaloidei Eichwald, 1831
  • Crotalina Bonaparte, 1831
  • Bothrophes Fitzinger, 1843
  • Crotalinae Cope, 1860
  • Teleuraspides Cope, 1871
  • Crotalida Strauch, 1873
  • Bothrophera Garman, 1884
  • Cophiinae Cope, 1895
  • Lachesinae Cope, 1900
  • Lachesinii Smith, Smith & Sawin, 1977
  • Agkistrodontinii Hoge & Romano-Hoge, 1981
  • Agkistrodontini Hoge & Romano-Hoge, 1983

The Crotalinae, commonly known as pit vipers, crotaline snakes (named for the Ancient Greek: κρόταλον krotalon castanet/rattle of a rattlesnake's tail), or pit adders, are a subfamily of venomous vipers found in Eurasia and the Americas. They are distinguished by the presence of a heat-sensing pit organ located between the eye and the nostril on either side of the head. Currently, 18 genera and 151 species are recognized: seven genera and 54 species in the Old World, against a greater diversity of 11 genera and 97 species in the New World. These are also the only viperids found in the Americas. The groups of snakes represented here include rattlesnakes, lanceheads, and Asian pit vipers. The type genus for this subfamily is Crotalus, of which the type species is the timber rattlesnake, C. horridus.

These snakes range in size from the diminutive hump-nosed viper, Hypnale hypnale, that grows to an average only 30–45 cm (12–18 in), to the bushmaster, Lachesis muta, a species known to reach a maximum of 3.65 m (12.0 ft) in length.

What makes this group unique is that they all share a common characteristic: a deep pit, or fossa, in the loreal area between the eye and the nostril on either side of the head. These loreal pits are the external openings to a pair of extremely sensitive infrared-detecting organs, which in effect give the snakes a sixth sense to help them find and perhaps even judge the size of the small, warm-blooded prey on which they feed.


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Wikipedia

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