Pythonidae

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Pythonidae
Indian python, Python molurus
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Infraorder: Alethinophidia
Family: Pythonidae
Fitzinger, 1826
Synonyms
  • Pythonoidea - Fitzinger, 1826
  • Pythonoidei - Eichwald, 1831
  • Holodonta - Müller, 1832
  • Pythonina - Bonaparte, 1840
  • Pythophes - Fitzinger, 1843
  • Pythoniens - A.M.C. Duméril & Bibron, 1844
  • Holodontes - A.M.C. Duméril & Bibron, 1844
  • Pythonides - A.M.C. Duméril & Bibron, 1844
  • Pythones - Cope, 1861
  • Pythonidae - Cope, 1864
  • Peropodes - Meyer, 1874
  • Chondropythonina - Boulenger, 1879
  • Pythoninae - Boulenger, 1890
  • Pythonini - Underwood & Stimson, 1990
  • Moreliini - Underwood & Stimson, 1990[1]

The Pythonidae, commonly known simply as pythons, from the Greek word python (πυθων), are a family of nonvenomous (though see the section "Toxins" below) snakes found in Africa, Asia and Australia. Among its members are some of the largest snakes in the world. Eight genera and 26 species are currently recognized.[2]

Geographic range[edit]

Pythons are found in sub-Saharan Africa, Nepal, India, Burma, southern China, Southeast Asia and from the Philippines southeast through Indonesia to New Guinea and Australia.[1]

In the United States, an introduced population of Burmese pythons, Python molurus bivittatus, has existed as an invasive species in the Everglades National Park since the late 1990s.[3]

Conservation[edit]

Many species have been hunted aggressively, which has decimated some, such as the Indian python, Python molurus.

Behavior[edit]

Black-headed python,
Aspidites melanocephalus

Most members of this family are ambush predators, in that they typically remain motionless in a camouflaged position and then strike suddenly at passing prey. They will generally not attack humans unless startled or provoked, although females protecting their eggs can be aggressive. Reports of attacks on human beings were once more common in South and Southeast Asia, but are now quite rare.

Feeding[edit]

Pythons use their sharp backward-curving teeth-- four rows in the upper jaw, two in the lower-- to grasp prey which is then killed by constriction; after an animal has been grasped to restrain it, the python will quickly wrap a number of coils around it. Death occurs primarily via asphyxiation; some research has suggested that pressures produced during constriction may cause cardiac arrest by interfering with blood flow,[4] but this hypothesis has not been confirmed.

Larger specimens usually eat animals about the size of a house cat, but larger food items are known: some large Asian species have been known to take down adult deer, and the African rock python, Python sebae, has been known to eat antelope. All prey is swallowed whole, and may take several days or even weeks to fully digest.

Contrary to popular belief,[by whom?] even the larger species, such as the reticulated python, P. reticulatus, do not crush their prey to death; in fact, prey is not even noticeably deformed before it is swallowed. The speed with which the coils are applied is impressive[peacock term] and the force they exert may be significant,[vague] but death is caused by suffocation, with the victim not being able to move its ribs to breathe while it is being constricted.[5][6][7]

Python skull
Python skull

Toxins[edit]

The research conducted by Bryan G. Fry et al. (2006) indicates that all snakes, including pythonids, are descended from a venomous ancestor.[8] A later study of Fry et al. (2013) indicates that, although the mandibular and maxillary glands of pythonids are primarily mucous-secreting, they also produce small quantities of toxins that are also known from venomous lizards and caenophidian snakes, including three-finger toxins (3FTx), lectin toxins and veficolin toxins. Presence of not only these but also other toxins in the snake Cylindrophis ruffus, as well as iguanians and monitor lizards, indicates that the production of small amounts of toxins by pythonids is a relic of once better-developed venom system that pythonids and boids have down-regulated, presumably because they developed powerful constriction as an alternative mean of killing their prey, leaving them with little need for a venom.[9]

Reproduction[edit]

Females lay eggs (oviparous). This sets them apart from the family Boidae (boas), most of which bear live young (ovoviviparous). After they lay their eggs, females will typically incubate them until they hatch. This is achieved by causing the muscles to "shiver", which raises the temperature of the body to a certain degree, and thus that of the eggs. Keeping the eggs at a constant temperature is essential for healthy embryo development. During the incubation period, females will not eat and only leave to bask to raise their body temperature.

Captivity[edit]

Most species in this family are available in the exotic pet trade. However, caution must be exercised with the larger species, as they can be dangerous; rare cases of large specimens killing their owners have been documented.[10]

Genera[edit]

Genus[2] Taxon author[2] Species[2] Subsp.*[2] Common name Geographic range[1]
Antaresia Wells & Wellington, 1984 4 0 Children's Pythons Australia in arid and tropical regions
Apodora Kluge, 1993 1 0 Papuan Pythons Most of New Guinea, from Misool to Fergusson Island
Aspidites Peters, 1877 2 0 Shield Pythons Australia except in the south of the country
Bothrochilus Fitzinger, 1843 1 0 Bismarck Ringed Pythons The islands of the Bismarck Archipelago, including Umboi, New Britain, Gasmata (off the southern coast), Duke of York and nearby Mioko, New Ireland and nearby Tatau (off the east coast), the New Hanover Islands and Nissan Island
Leiopython Hubrecht, 1879 1 0 White-Lipped Pythons Most of New Guinea (below 1200 m), including the islands of Salawati and Biak, Normanby, Mussau, as well as a few islands in the Torres Strait
Liasis Gray, 1842 3 2 Water Pythons Indonesia in the Lesser Sunda Islands, east through New Guinea and in northern and western Australia
Morelia Gray, 1842 7 5 Tree Pythons From Indonesia in the Maluku Islands, east through New Guinea, including the Bismarck Archipelago and in Australia
PythonT Daudin, 1803 7 4 True Pythons Africa in the tropics south of the Sahara (not including southern and extreme southwestern Madagascar), Bangladesh, Pakistan, India, Sri Lanka, the Nicobar Islands, Burma, Indochina, southern China, Hong Kong, Hainan, the Malayan region of Indonesia and the Philippines

*) Not including the nominate subspecies.
T) Type genus.[1]

Taxonomy[edit]

Pythons are more closely related to boas than to any other snake family. Boulenger (1890) considered this group to be a subfamily (Pythoninae) of the family Boidae (boas).[1]

References[edit]

  1. ^ a b c d e McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
  2. ^ a b c d e "Pythonidae". Integrated Taxonomic Information System. Retrieved 15 September 2007. 
  3. ^ "Huge, Freed Pet Pythons Invade Florida Everglades", National Geographic News. Accessed 16 September 2007.
  4. ^ Hardy, David L. (1994). "A re-evaluation of suffocation as the cause of death during constriction by snakes". Herpetological Review 229: 45-47.
  5. ^ Mehrtens JM. 1987. Living Snakes of the World in Color. New York: Sterling Publishers. 480 pp. ISBN 0-8069-6460-X.
  6. ^ Stidworthy J. 1974. Snakes of the World. Grosset & Dunlap Inc. 160 pp. ISBN 0-448-11856-4.
  7. ^ Carr A. 1963. The Reptiles. Life Nature Library. Time-Life Books, New York. 192 pp. LCCCN 63-12781.
  8. ^ Bryan G. Fry, Nicolas Vidal, Janette A. Norman, Freek J. Vonk, Holger Scheib, S. F. Ryan Ramjan, Sanjaya Kuruppu, Kim Fung, S. Blair Hedges, Michael K. Richardson, Wayne. C. Hodgson, Vera Ignjatovic, Robyn Summerhayes, Elazar Kochva (2006). "Early evolution of the venom system in lizards and snakes". Nature 439 (7076): 584–588. doi:10.1038/nature04328. PMID 16292255. 
  9. ^ Bryan G. Fry, Eivind A. B. Undheim, Syed A. Ali, Jordan Debono, Holger Scheib, Tim Ruder, Timothy N. W. Jackson, David Morgenstern, Luke Cadwallader, Darryl Whitehead, Rob Nabuurs, Louise van der Weerd, Nicolas Vidal, Kim Roelants, Iwan Hendrikx, Sandy Pineda Gonzalez, Alun Jones, Glenn F. King, Agostinho Antunes, Kartik Sunagar (2013). "Squeezers and leaf-cutters: differential diversification and degeneration of the venom system in toxicoferan reptiles". Molecular & Cellular Proteomics 12 (7): 1881–1899. doi:10.1074/mcp.M112.023143. 
  10. ^ "The Keeping of Large Pythons" at Anapsid. Accessed 16 September 2007.

External links[edit]