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{{this|the animal|Snake (disambiguation)}}
{{Taxobox
| name = Snake
| fossil_range = ] - ]
| image = Antaresia maculosa.jpg
| image_width = 250px
| image_caption = Spotted Python<br/>'']''
| regnum = ]ia
| phylum = ]
| subphylum = ]
| classis = ]a
| subclassis = ]
| infraclassis = ]
| superordo = ]
| ordo = ]
|<!-- unranked_ordo = ] this does not work -->
| subordo = '''Serpentes'''
| subordo_authority = ], ]
| subdivision_ranks = ]s and ]
| subdivision =
* ] - <small>], ]</small>
** ]- <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>Cundall, Wallach & Rossman, 1993</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>Hoffstetter, ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], 1832</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
* ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
** ] - <small>], ]</small>
}}
A '''snake''' is an elongate ] of the suborder ''Serpentes''. Like all reptiles, snakes are covered in ]. All snakes are ] and can be distinguished from ] by their lack of eyelids, limbs, external ears, and vestiges of forelimbs. The 2,700+ species of snakes spread across every continent except Antarctica ranging in size from the tiny, 10&nbsp;cm long ] to ] and ]s over 5&nbsp;m long. In order to accommodate snakes' narrow bodies, paired organs (such as kidneys) appear one in front of the other instead of side by side. The snake is one of the most feared animals because of its association with evil and the common misconception that all snakes are venomous. They were viewed as the devil's creatures.

While venomous snakes comprise a minority of the species, some possess potent venom capable of causing painful injury or death to humans. However, venom in snakes is primarily for killing and subduing prey rather than for self-defense.
Snakes may have evolved from a lizard which adapted to burrowing during the ] period (''c'' 150 ]), though some scientists have postulated an aquatic origin. The diversity of modern snakes appeared during the ] period (''c'' 66 to 56 Ma).

A literary word for snake is '''serpent''' (a ] word which comes from ], and ultimately from ''*serp-'', "to creep"<ref name="serpent">{{cite web | work=Merriam-Webster Online Dictionary | title=Definition of serpent - Merriam-Webster Online Dictionary|url=http://www.merriam-webster.com/dictionary/serpent| accessdate=12 October|accessyear=2006}}</ref>). In modern usage, the term serpent usually refers to a mythic or ]. In ], the serpent is sometimes identified with the devil, as in the Biblical account of ], but also with healing, as in the Biblical account of the brass serpent of Moses. The serpent is also the symbol of the healing arts.

==Introduction==
].]] All snakes are strictly ], eating small animals including lizards, other snakes, small mammals, birds, ], fish, snails or insects.<ref name="Sanchez"/><ref name="Bebler79_581">Bebler (1979) p.581</ref><ref name="Mehrtens_1987_81"/> Because snakes cannot bite or tear their food to pieces, prey must be swallowed whole. The body size of a snake has a major influence on its eating habits. Smaller snakes eat smaller prey. Juvenile pythons might start out feeding on lizards or mice and graduate to small deer or antelope as an adult, for example.

The snake's ] is the most unique jaw in the animal kingdom. Contrary to the popular belief that snakes can dislocate their jaws, snakes have a very flexible ], the two halves of which are not rigidly attached, and numerous other joints in their ] (see ]), allowing them to open their mouths wide enough to swallow their prey whole, even if it is larger in diameter than the snake itself,<ref name="Bebler79_581"/> as snakes do not chew. For example, the ] has flexible jaws adapted for eating eggs much larger than the diameter of its head.<ref name="Mehrtens_1987_81"/> This snake has no ], but does have bony protrusions on the inside edge of its ] which are used to aid in breaking the shells of the eggs it eats.<ref name="Mehrtens_1987_81">Mehrtens (1987), p.81</ref>

While the majority of snakes eat a variety of prey animals, there is some specialization by some species. ]s and the Australian ] consume other snakes. ''Pareas iwesakii'' and other ]-eating ]s of subfamily ] have more teeth on the right side of their mouths than on the left, as the shells of their prey usually spiral clockwise<ref>Hoso, M., T. Takahiro & M. Hori. (2007) "Right-handed snakes: convergent evolution of asymmetry for functional specialization." ''Biol. Lett.'' '''3''': 169-72.</ref><ref>Mehrtens (1987), p.184</ref>

Some snakes have a venomous bite, which they use to kill their prey before eating it.<ref>Freiberg (1984), pp.125-127</ref><ref name="Bebler79_581"/> Other snakes kill their prey by ].<ref name="Bebler79_581"/> Still others swallow their prey whole and alive.<ref name="Bebler79_581"/><ref name="Mehrtens_1987_81"/>
]]]

After eating, snakes become dormant while the process of ] takes place.<ref name="Rosenfeld_11"> Rosenfeld(1989), p.11</ref> Digestion is an intense activity, especially after consumption of very large prey. In species that feed only sporadically, the entire ] enters a reduced state between meals to conserve energy, and the digestive system is 'up-regulated' to full capacity within 48 hours of prey consumption. Being cold-blooded (ectothermic), the surrounding temperature plays a large role in a snake's digestion. 30 degrees ] is the ideal temperature for snakes to digest their food. So much ] energy is involved in a snake's digestion that in ''Crotalus durissus'', the Mexican rattlesnake, an increase of body temperature to as much as 1.2 degrees celsius above the surrounding environment has been observed.<ref> {{cite web
| coauthors =Glenn J. Tattersall1, William K. Milsom, Augusto S. Abe, Simone P. Brito, Denis V. Andrade
| year = 2004
| url =http://jeb.biologists.org/cgi/content/abstract/207/4/579
| title =The thermogenesis of digestion in rattlesnakes
| work =Journal of Experimental Biology 207
| pages =579-585
| publisher =The Company of Biologists
| accessdate =2006-05-26
| accessyear =2006
}}</ref> Because of this, a snake disturbed after having eaten recently will often ] its prey in order to be able to escape the perceived threat. When undisturbed, the digestive process is highly efficient, with the snake's digestive ] dissolving and absorbing everything but the prey's ] and ], which are excreted along with ].

==Taxonomy==
'']'' within the entire ] ''Serpentes'' in ].<ref name="ITIS">{{ITIS|ID=174118|taxon=Serpentes|year=2007|date=20 August}}</ref> There are two ]s of ''Serpentes'': ] and ].<ref name="ITIS"/> This separation is based primarily on ] characteristics between family groups and ].

As with a lot of taxonomic classifications, there are many debates when it comes to how many there are. For instance, many sources classify ] and ] as the same family, or keep others, such as ] and ], separate for practical reasons despite their extremely close relation.

{| class="wikitable"
|-
|colspan="100%" align="center" {{bgcolor-blue}}|''']''' 15 families
|-
!Family!!Common Names!!Example Species!!Example Photo
|-
|]<br><small>], 1831</small><ref name="Cogger91_23"/>||file snakes||] (''Acrochordus granulatus'')||]
|-
|]<br><small>], 1907</small><ref>{{ITIS|ID=209611|taxon=Aniliidae|year=2007|date=12 December}}</ref> ||coral pipe snakes||] (''Anilius scytale'')||
|-
|]<br><small>Cundall, Wallach, 1993</small>.<ref>{{ITIS|ID=563894|taxon=Anomochilidae|year=2007|date=13 December}}</ref>||dwarf pipe snakes||], (''Anomochilus leonardi'')||
|-
|]<br><small>], 1858</small><ref>{{ITIS|ID=563895|taxon=Atractaspididae|year=2007|date=13 December}}</ref>
||mole vipers||] (''Atractaspis bibroni'') ||
|-
|]<br><small>], 1825</small><ref name="Cogger91_23">Cogger(1991), p.23</ref>||tree boa, Russell's earth boa, red sand boa, Indian python||] (''Corallus hortulanus,'')||]
|-
|]<br><small>], 1946</small>||Round Island boas||] (''Bolyeria multocarinata'')||
|-
|]<br><small>], 1811</small><ref name="Cogger91_23"/>||colubrids, Common wolf snake, yellow spotted wolf snake, common kukri snake, streaked kukri snake, dumeril's black headed snake, buffstriped keel back, green keel back, checkered keel back, trinket snake, Rat snake, cat snake, glossy marsh snake, Indian ribbon snake, common vine snake||] (''Natrix natrix'')||]
|-
|]<br><small>||Japanese Rat Snake||](''Elaphe climacophora'')||]
|-
|]<br><small>], 1843</small>||Asian pipe snakes||] (''Cylindrophis ruffus'')|| ]
|-
|]<br><small>], 1827</small><ref name="Cogger91_23"/>||cobras, coral snakes, mambas, kraits, sea snakes, sea kraits, Australian elapids||] (''Ophiophagus hannah'')||]
|-
|]<br><small>], 1861</small>||Mexican burrowing snakes||] (''Loxocemus bicolor'')||]
|-
|]<br><small>], 1826</small>||pythons||]/] (''Python regius'')||]
|-
|]<br><small>], 1951</small>||dwarf boas||] (''Trachyboa boulengeri'') ||
|-
|]<br><small>], 1832</small>||shield-tailed snakes, short-tailed snakes||] (''Uropeltis ocellatus'')||
|-
|]<br><small>], 1811</small><ref name="Cogger91_23"/>||vipers, pitvipers, rattlesnakes||] (''Vipera aspis'')||]
|-
|]<br><small>], 1845</small>||sunbeam snakes||] (''Xenopeltis unicolor'')||
|-
|colspan="100%" align="center" {{bgcolor-blue}}|''']''' 3 families
|-
!Family!!Common Names!!Example Species!!Example Photo
|-
|]<br><small>], 1939</small><ref name="Cogger91_23"/>||dawn blind snakes||] (''Liotyphlops beui'')||<!-- Commented out because image was deleted: ] -->
|-
|]<br><small>], 1892</small><ref name="Cogger91_23"/>||slender blind snakes||] (''Leptotyphlops dulcis'')||]
|-
|]<br><small>], 1820</small><ref>{{ITIS|ID=174338|taxon=Typhlopidae|year=2007|date=13 December}}</ref>||blind snakes||] (''Typhlops reticulatus'')||<!-- Commented out because image was deleted: ] -->
|}

==Evolution==
] of snakes is poorly known because snake ]s are typically small and fragile, making ] uncommon. However 150 million-year-old specimens readily definable as snakes with lizardlike skeletal structures have been uncovered in ] and ].<ref name="Mehrtens87_11">Mehrtens (1987) p. 11</ref> It has been agreed, on the basis of ], that snakes descended from ]s.<ref name="Sanchez">
{{citation
| last = Sanchez
| first = Alejandro
| title = Diapsids III: Snakes
| work= Father Sanchez's Web Site of West Indian Natural History
| url = http://www.kingsnake.com/westindian/metazoa12.html
| accessdate = 2007-11-26
}}
</ref><ref name="Mehrtens87_11"/> Molecular evidence reinforces this; it is hypothesized{{Fact|date=May 2008}} that snakes share a common venomous ancestor with several lizard families, forming the ] clade.

Fossil evidence suggests that snakes may have evolved from burrowing lizards, such as ]s or a similar group during the ].<ref name="EB">{{Citation
| last =Mc Dowell
| first =Samuel
| title =The evolution of the tongue of snakes and its bearing on snake origins
| journal =Evolutionary Biology
| year =1972
| volume=6
| pages = 191-273
}}
</ref> An early fossil snake, '']'', was a two-legged burrowing animal with a ], and was fully ].<ref>
{{cite journal
| last = Apesteguía
| first = Sebastián
| coauthors = Hussam Zaher
| year = 2006
| month = April
| title = A Cretaceous terrestrial snake with robust hindlimbs and a sacrum
| journal = Nature
| volume = 440
| issue = 7087
| pages = 1037&ndash;1040
| doi = 10.1038/nature04413
| url = http://www.nature.com/nature/journal/v440/n7087/edsumm/e060420-11.html | accessdate = 2007-11-29 }}
</ref> One extant analog of these putative ancestors is the earless monitor '']'' of ], although it also is semi-].<ref name="M2">{{Citation
| last =Mertens
| first =Robert
| title =Lanthanotus: an important lizard in evolution
| journal =Sarawak Museum Journal
| year =1961
| volume=10
| pages = 320-322
}}</ref> As these ancestors became more ], they lost their limbs and their bodies became more streamlined for burrowing.<ref name="M2"/> According to this hypothesis, features such as the ], fused eyelids (]) and loss of external ears evolved to combat subterranean conditions such as scratched corneas and dirt in the ears with snakes re-emerged onto the surface of the earth much as they are today.<ref name="M2"/><ref name="EB"/> Other primitive snakes are known to have possessed hindlimbs but lacked a direct connection of the pelvic bones to the vertebrae, including '']'', '']'' and ''Eupodophis'', which are slightly older than '']''.<ref name="legs">
{{cite web
| title = New Fossil Snake With Legs
| work = UNEP WCMC Database
| publisher =American Association For The Advancement Of Science
| location = ]
| url =http://www.wildlifenews.co.uk/articles2000/march/march2500a.htm
| accessdate =2007-11-29 }}
</ref>
]
Primitive groups among the modern snakes, ]s and ]s, have vestigial hind limbs: tiny, clawed digits known as ]s which are used to grasp during mating.<ref name="legs"/><ref name="Mehrtens87_11"/> ] and ] are other examples where remnants of the pelvic girdle are still present, sometimes appearing as horny projections when visible. The frontal limbs in all snakes are non-existent because of the evolution of the ]s in this area. The axial skeleton of the snakes' common ancestor had like most other tetrapods the familiar regional specializations consisting of cervical (neck), thoracic (chest), lumbar (lower back), sacral (pelvic) and caudal (tail) vertebrae. The Hox gene expression in the axial skeleton responsible for the development of the thorax became dominant early in snake evolution and as a result, the vertebrae anterior to the hindlimb buds (when present) all have the same thoracic-like identity (except from the ], ] and 1-3 neck vertebrae), making most of the snake's skeleton being composed of an extremely extended thorax. Ribs are found exclusively on the thoracic vertebrae. The neck, lumbar and pelvic vertebrae are very reduced in number (only 2-10 lumbar and pelvic vertebrae are still present), while only a short tail remains of the caudal vertebrae, although the tail is still long enough to be of good use in many species, and is modified in some aquatic and tree dwelling species.

An alternative hypothesis, based on ], suggests that the ancestors of snakes were related to ]s &mdash; extinct ] reptiles from the ] &mdash; which in turn are thought to have derived from ]s.<ref name="Sanchez"/> Under this hypothesis, the fused, transparent eyelids of snakes are thought to have evolved to combat marine conditions (corneal water loss through osmosis), while the external ears were lost through disuse in an aquatic environment, ultimately leading to an animal similar in appearance to ]s of today. In the Late ], snakes re-colonized the land much like they are today. Fossil snake remains are known from early Late Cretaceous marine sediments, which is consistent with this hypothesis, particularly as they are older than the terrestrial ''Najash rionegrina''. Similar skull structure; reduced/absent limbs; and other anatomical features found in both mosasaurs and snakes lead to a positive ]al correlation, although some of these features are shared with ]s. In recent years, genetic studies have indicated that snakes are not as closely related to monitor lizards as it was once believed, and therefore not to mosasaurs, the proposed ancestor in the aquatic scenario of their evolution. However, there is more evidence linking mosasaurs to snakes than to varanids. Fragmentary remains that have been found from the ] and Early Cretaceous indicate deeper fossil records for these groups, which may eventually refute either hypothesis.
] ''Micrurus tener'']]
The great diversity of modern snakes appeared in the ], correlating with the ] of mammals following the extinction of the non-avian ]s. There are over 2,900 species of snakes ranging as far northward as the ] in ] and southward through ] and ].<ref name="Sanchez"/> Snakes can be found on every continent (with the exception of ]), dwelling in the sea, and as high as 16,000 feet (4900m)in the ] of ].<ref name="Sanchez"/><ref name="Conant91_143">Conant (1991), p.143</ref> There are numerous islands from which snakes are conspicuously absent such as ], ], and ].<ref name="Conant91_143"/>

==Skin==
{{main|Snake scales}}

The ] of a snake is covered in ]s. Contrary to the popular notion of snakes being slimy because of possible confusion of snakes with ]s, snakeskin has a smooth, dry texture. Most snakes use specialized belly scales to travel, gripping surfaces. The body scales may be smooth, ], or granular. Snake's eyelids are transparent "spectacle" scales which remain permanently closed, also known as brille.

The shedding of scales is called '']'', or, in normal usage '']ing'' or ''sloughing''. In the case of snakes, the complete outer layer of skin is shed in one layer.<ref name = "Smith1_30"> Smith, Malcolm A. Fauna of British India...Vol I - Loricata and Testudines, page 30 </ref> Snake scales are not discrete but extensions of the epidermis hence they are not shed separately, but are ejected as a complete contiguous outer layer of skin during each ], akin to a sock being turned inside out.<ref name="RSSlimy"> at [http://www.szgdocent.org/ Singapore Zoological Garden's Docent. Accessed 14 August 2006.</ref>
]

]ing serves a number of functions - firstly, the old and worn skin is replaced, secondly, it helps get rid of parasites such as mites and ticks. Renewal of the skin by ]ing is supposed to allow growth in some animals such as insects, however this view has been disputed in the case of snakes.<ref name="RSSlimy"/><ref name="ZooPax3"> </ref>
]

Moulting is repeated periodically throughout a snake's life. Before a moult, the snake stops eating and often hides or moves to a safe place. Just before shedding, the skin becomes dull and dry looking and the eyes become cloudy or blue-colored. The inner surface of the old outer skin liquefies. This causes the old outer skin to separate from the new inner skin. After a few days, the eyes clear and the snake "crawls" out of its old skin. The old skin breaks near the mouth and the snake wriggles out aided by rubbing against rough surfaces. In many cases the cast skin peels backward over the body from head to tail, in one piece like an old sock. A new, larger, and brighter layer of skin has formed underneath.<ref name="RSSlimy"/><ref name = "GenSnakeInfo"> </ref>

An older snake may shed its skin only once or twice a year, but a younger, still-growing snake, may shed up to four times a year.<ref name = "GenSnakeInfo"/> The discarded skin gives a perfect imprint of the scale pattern and it is usually possible to identify the snake if this discard is reasonably complete and intact.<ref name="RSSlimy"/> Although the primary purpose of ] is for the snake's growth; it also removes external ]s. This periodic renewal has led to the snake being a symbol of healing and medicine, as pictured in the ].<ref name=AIM>{{cite journal
|last=Wilcox
|first=Robert A
|last2=Whitham
|first2= Emma M
|title=The symbol of modern medicine: why one snake is more than two
|date=15 April 2003
|url=http://www.annals.org/cgi/content/full/138/8/673
|journal=Annals of Internal Medicine
|accessdate=2007-11-26}}</ref>

The shape and number of scales on the head, back and belly are characteristic to family, genus and species. Scales have a nomenclature analogous to the position on the body. In "advanced" (]n) snakes, the broad belly scales and rows of ]s correspond to the ]e, allowing scientists to count the vertebrae without ].

Scalation counts are also used to tell the sex of a snake when the species is not readily sexually dimorphic. A probe is inserted into the ] until it can go no further. The probe is marked at the point where it stops, removed, and compared to the subcaudal depth by laying it alongside the scales.<ref name="Rosenfeld_11"/> The scalation count determines whether the snake is a male or female as hemipenes of a male will probe to a different depth (usually longer) than the cloaca of a female.<ref name="Rosenfeld_11"/>

==Perception==
]
===Eyesight===
Snake ] is remarkable. Generally, vision is best in arboreal snakes and worst in burrowing snakes. Snakes can detect movement.<ref name="Cogger91_180"/> Some snakes, such the Asian vine snake (genus '']''), have ], with both eyes capable of focusing on the same point. Most snakes focus by moving the ] back and forth in relation to the ], while in all other vertebrates, the lens is stretched.

===Smell===
Snakes use smell to track their prey. It smells by using its ] to collect airborne particles then passing them to the ] in the ] for examination.<ref name="Cogger91_180">Cogger(1991), p.180</ref> The fork in the tongue gives the snake a sort of directional sense of smell and taste simultaneously.<ref name="Cogger91_180"/> The snake keeps its tongue constantly in motion, sampling particles from the air, ground, and water analyzing the chemicals found and determining the presence of prey or predators in its local environment.<ref name="Cogger91_180"/>

===Vibration sensitivity===
The part of the body which is in direct contact with the surface of the ground is very sensitive to vibration, thus a snake is able to sense other animals approaching through detecting faint vibrations in the air and on the ground.<ref name="Cogger91_180"/>

===Infrared sensitivity===
Pit vipers, pythons, and some boas have ] in deep grooves between the nostril and eye, although some have labial pits on their upper lip just below the nostrils (common in pythons) which allow them to "see" the radiated heat.<ref name="Cogger91_180"/> Infrared sensitivity helps snakes locate nearby prey, especially warm-blooded mammals.

==Internal organs==
{{snake anatomy imagemap}}
As with all reptiles, snakes are ].

The snake's heart is encased in a sac, called the '']'', located at the ] of the ]. The heart is able to move around, however, owing to the lack of a diaphragm. This adjustment protects the heart from potential damage when large ingested prey is passed through the esophagus. The ] is attached to the ] and ] and filters the blood. The ] is located in fatty tissue above the heart and is responsible for the generation of immune cells in the blood. The cardiovascular system of snakes is also unique for the presence of a renal portal system in which the blood from the snake's tail passes through the kidneys before returning to the heart.<ref name="Mader"/>

The ] left ] is often small or sometimes even absent, as snakes' tubular bodies require all of their organs to be long and thin.<ref name="Mader">
{{Citation
| last = Mader
| first = Douglas
| title = Reptillian Anatomy
| journal = Reptiles
| volume =3
| issue =2
| pages =84-93
| date = June 1995
| year = 1995
}}
</ref> In the majority of species, only one ] is functional. This lung contains a vascularized anterior portion and a posterior portion which does not function in gas exchange.<ref name="Mader"/> This 'saccular lung' is used for ] purposes to adjust buoyancy in some aquatic snakes and its function remains unknown in terrestrial species.<ref name="Mader"/> Many organs that are paired, such as ] or ], are staggered within the body, with one located ahead of the other.<ref name="Mader"/> Snakes have no colenary bladder or ]s.<ref name="Mader"/>

==Locomotion==
The lack of limbs does not impede the movement of snakes, and they have developed several different modes of locomotion to deal with particular environments. Unlike the gaits of limbed animals, which form a continuum, each mode of snake locomotion is discrete and distinct from the others, and transitions between modes are abrupt.<ref name="Cogger91_175">Cogger(1991), p.175</ref><ref name = "Gray">
{{Citation
| last = Gray
| first = J.
| title = The mechanism of locomotion in snakes
| journal = Journal of experimental biology
| year = 1946
| volume = 23
| issue = 2
| pages= 101 - 120 }}
</ref>

===Lateral undulation===
{{see also|Lateral undulation}}
] is the sole mode of aquatic locomotion, and the most common mode of terrestrial locomotion.<ref name = "Gray"/> In this mode, the body of the snake alternately flexes to the left and right, resulting in a series of rearward-moving 'waves'.<ref name="Cogger91_175"/> While this movement appears rapid, snakes have been documented moving faster than 2 body-lengths per second, often much less.<ref name = "Hekrotte">
{{Citation
| last = Hekrotte
| first = Carlton
| title = Relations of Body Temperature, Size, and Crawling Speed of the Common Garter
Snake, Thamnophis s. sirtalis
| journal = Copeia
| year = 1967
| volume = 23
| issue = 4
| pages= 759 - 763 }}
</ref> This mode of movement is similar to running in lizards of the same mass.<ref name = "Walton">
{{Citation
| last = Walton
| first = M.
| last2 = Jayne
| first2 = B.C.
| last3 = Bennett
| first3 = A.F.
| title = The energetic cost of limbless locomotion
| journal = Science
| year = 1967
| volume = 249
| issue = 4
| pages= 524-527 }}
</ref>
:'''Terrestrial'''
:: Terrestrial lateral undulation is the most common mode of terrestrial locomotion for most snake species.<ref name="Cogger91_175"/> In this mode, the posteriorly-moving waves push against contact points in the environment, such as rocks, twigs, irregularities in the soil, etc.<ref name="Cogger91_175"/> Each of these environmental objects, in turn, generates a reaction force directed forward and towards the midline of the snake, resulting in forward thrust while the ]'']]lateral components cancel out.<ref name = "Gray_lissman"/> The speed of this movement depends upon the density of push-points in the environment, with a medium density of about 8 along the snake's length being ideal.<ref name = "Hekrotte"/> The wave speed is precisely the same as the snake speed, and as a result, every point on the snake's body follows the path of the point ahead of it, allowing snakes to move through very dense vegetation and small openings.<ref name = "Gray_lissman">
{{Citation
| last = Gray
| first = J
| last2 = Lissman
| last2 = H.W.
| title = Kinetics of locomotion of the grass snake
| journal = Journal of experimental biology
| year = 1950
| volume = 26
| pages= 354-367 }}
</ref>
:'''Aquatic'''
::When swimming, the waves become larger as they move down the snake's body, and the wave travels backwards faster than the snake moves forwards.<ref name = "Gray2">
{{Citation
| last = Gray
| first = J
| last2 = Lissman
| title = Undulatory propulsion
| journal = Quarterly Journal of Micro. Science
| year = 1953
| volume = 94
| pages= 551-578 }}
</ref> Thrust is generated by pushing their body against the water, resulting in the observed slip. In spite of overall similarities, studies show that the pattern of muscle activation is different in aquatic vs terrestrial lateral undulation, which justifies calling them separate modes.<ref name = "Jayne1">
{{Citation
| last = Jayne
| first = B.C.
| title = Muscular mechanisms of snake locomotion: an electromyographic study of lateral undulation of the Florida banded water snake (Nerodia fasciata) and the yellow rat snake (Elaphe obsoleta)
| journal = Journal of Morphology
| year = 1988
| volume = 197
| pages= 159-181 }}
</ref> All snakes can laterally undulate forward (with backward-moving waves), but only ] have been observed reversing the pattern, i.e. moving backwards via forward-traveling waves.<ref name="Cogger91_175"/>

===Sidewinding===
]
{{see also|Sidewinding}}
Most often employed by colubroid snakes (colubrids, elapids, and vipers) when the snake must move in an environment which lacks any irregulaties to push against (and which therefore renders lateral undulation impossible), such as a slick mud flat or sand dune sidewinding is a modified form of lateral undulation in which all of the body segments oriented in one direction remain in contact with the ground, while the other segments are lifted up, resulting in a peculiar 'rolling' motion.<ref name="Cogger91_177">Cogger(1991), p.177</ref><ref name = "Jayne2">
{{Citation
| last = Jayne
| first = B.C.
| title = Kinematics of terrestrial snake locomotion
| journal = Copeia
| year = 1986
| pages= 915-927 }}
</ref> This mode of locomotion overcomes the slippery nature of sand or mud by pushing off with only static portions on the body, thereby minimzing slipping.<ref name="Cogger91_177"/> The static nature of the contact points can be shown from the tracks of a sidewinding snake, which show each belly scale imprint, without any smearing. This mode of locomotion has very low caloric cost, less than ⅓ of the cost for a lizard or snake to move the same distance.<ref name="Walton"/> Contrary to popular beliefs, there is no evidence that sidewinding is associated with hot sand.<ref name="Cogger91_177"/>

===Concertina locomotion===
{{see also|Concertina movement}}
When push-points are absent, but there is not enough space to use sidewinding because of lateral constraints, such as in tunnels, snakes rely on concertina locomotion.<ref name="Cogger91_175"/><ref name = "Jayne2"/> In this mode, the snake braces the posterior portion of its body against the tunnel wall while the front of the snake extends and straightens.<ref name="Cogger91_177"/> The front portion then flexes and forms an anchor point, and the posterior is straightened and pulled forwards. This mode of locomotion is slow and very demanding, up to seven times the cost of laterally undulating over the same distance.<ref name="Walton"/> This high cost is due to the repeated stops and starts of portions of the body as well as the necessity of using active muscular effort to brace against the tunnel walls.

===Rectilinear locomotion===
{{see also|Rectilinear locomotion}}
The slowest mode of snake locomotion is rectilinear locomotion, which is also the only one in which the snake does not need to bend its body laterally, though it may do so when turning.<ref name="Cogger91_176">Cogger(1991), p.176 </ref> In this mode, the belly scales are lifted and pulled forward before being placed down and the body pulled over them. Waves of movement and stasis pass posteriorly, resulting in a series of ripples in the skin.<ref name="Cogger91_176"/> The ribs of the snake do not move in this mode of locomotion and this method is most often used by large ]s, ]s, and ]s when stalking prey across open ground as the snake's movements are subtle and harder to detect by their prey in this manner.<ref name="Cogger91_177"/>

===Other===
The movement of snakes in arboreal habitats has only recently been studied.<ref name="Cogger91_177"/> While on tree branches, snakes use several modes of locomotion depending on species and bark texture.<ref name="Cogger91_177"/> In general, snakes will use a modified form of concertina locomotion on smooth branches, but will laterally undulate if contact points are available. Snakes move faster on small branches and when contact points are present, in contrast to limbed animals, which do better on large branches with little 'clutter'.

Gliding snakes (]) of Southeast Asia launch themselves from branch tips, spreading their ribs and laterally undulating as they glide between trees.<ref name = "Astley">{{Citation
| last = Astley
| first =H.C.
| last2 = Jayne
| first2 = B.C.
| title = Effects of perch diameter and incline on the kinematics, performance and modes of arboreal locomotion of corn snakes (Elaphe guttata)
| year = 2007.
| journal = Journal of Experimental Biology
|volume = 210
|pages = 3862-3872
}}</ref><ref name="Cogger91_177"/><ref>Freiberg(1984). p.135</ref><ref>Socha, J.J. 2002. Gliding flight in the paradise tree snake. Nature 418, 603-604.</ref> These snakes can perform a controlled glide for hundreds of feet depending upon launch altitude and can even turn in mid-air.<ref name="Cogger91_177"/><ref>Freiberg(1984). p.135</ref>

==Reproduction==
Although a wide range of reproductive modes are used by snakes; all snakes employ ], accomplished by means of paired, forked ], which are stored inverted in the male's tail.<ref name="Capula89_117">Capula (1989), p.117</ref> The hemipenes are often grooved, hooked, or spined in order to grip the walls of the female's ].<ref name="Capula89_117"/>

Most species of snake lay ], and most of those species abandon them shortly after laying; however, individual species such as the ] actually construct nests and stay in the vicinity of the hatchlings after incubation.<ref name="Capula89_117"/> Most pythons coil around their egg-clutches after they have laid them and remain with the eggs until they hatch.<ref name="Cogger91_186">Cogger (1991), p.186</ref> The female python will not leave the eggs, except to occasionally bask in the sun or drink water and will generate heat to incubate the eggs by shivering.<ref name="Cogger91_186"/>

Some species of snake are ] and retain the eggs within their bodies until they are almost ready to hatch.<ref name="Capula89_118">Capula (1989), p.118</ref><ref name="Cogger91_182">Cogger (1991), p.182</ref> Recently, it has been confirmed that several species of snake are fully ], such as the ] and ], nourishing their young through a ] as well as a ], which is highly unusual among reptiles, or anything else outside of ].<ref name="Capula89_118"/><ref name="Cogger91_182"/> Retention of eggs and live birth are most often associated with colder environments, as the retention of the young within the ].<ref name="Capula89_117"/><ref name="Cogger91_182"/>

== Venom ==
{{see also|Snake venom}}
], one fang with a small venom stain in glove, the other still in place]]
Cobras, vipers, and closely related species use ] to immobilize or kill their prey. The venom is modified ], delivered through ]s.<ref name= "Mehrtens87_243">Mehrtens (1987), p.243</ref> The fangs of 'advanced' venomous snakes like viperids and elapids are hollow in order to inject venom more effectively, while the fangs of rear-fanged snakes such as the Boomslang merely have a groove on the posterior edge to channel venom into the wound. Snake venoms are often prey specific, its role in self-defense is secondary.<ref name= "Mehrtens87_243"/> Venom, like all salivary secretions, is a pre-digestant which initiates the breakdown of food into soluble compounds allowing for proper digestion and even "non-venomous" snake bites (like any animal bite) will cause tissue damage.<ref name="Mehrtens87_209">Mehrtens (1987), p.209</ref>

Certain birds, mammals, and other snakes such as ]s that prey on venomous snakes have developed resistance and even immunity to certain venom.<ref name= "Mehrtens87_243"/> Venomous snakes include three ] of snakes and do not constitute a formal ] group used in ]. The term '''poisonous snake''' is mostly incorrect - poison is inhaled or ingested whereas venom is injected.<ref name="Freiberg84_125"/> There are, however, two examples - ] sequesters toxins from the toads it eats then secretes them from nuchal glands to ward off predators, and a small population of ] in Oregon retains enough toxin in their liver from the newts they eat to be effectively poisonous to local small predators such as crows and foxes.<ref name="Freiberg84_123">Freiberg (1984), p.123</ref>

Snake venoms are complex mixtures of ]s and are stored in poison glands at the back of the head.<ref name="Freiberg84_123"/> In all venomous snakes these glands open through ducts into grooved or hollow teeth in the upper jaw.<ref name= "Mehrtens87_243"/><ref name="Freiberg84_125">Freiberg (1984), p.125</ref> These proteins can potentially be a mix of ]s (which attack the nervous system), ]s (which attack the circulatory system), ]s, ]s and many other toxins that affect the body in different ways.<ref name="Freiberg84_125"/> Almost all snake venom contains ''hyaluronidase'', an enzyme that ensures rapid diffusion of the venom.<ref name= "Mehrtens87_243"/>

Venomous snakes that use hemotoxins usually have the fangs that secrete the venom in the front of their mouths, making it easier for them to inject the venom into their victims.<ref name="Freiberg84_125"/> Some snakes that use neurotoxins, such as the ], have their fangs located in the back of their mouths, with the fangs curled backwards.<ref name="Freiberg84_126">Freiberg (1984), pp.126</ref> This makes it both difficult for the snake to use its venom and for scientists to milk them.<ref name="Freiberg84_125"/> '']'' snakes, however, such as ]s and ]s are ''proteroglyphous'', possessing hollow fangs which cannot be erected toward the front of their mouths and cannot "stab" like a viper, they must actually bite the victim.<ref>Mehrtens (1987), p.242</ref>

It has recently been suggested that all snakes may be venomous to a certain degree, the harmless snakes having weak venom and no fangs.<ref name="Fry_2006_earlyevolution">
{{citation | last = Fry | first = Brian G | last2 = Vidal | first2 = Nicholas | last3 = Norman | first3 = Janette A. | last4 = Vonk | first4 = Freek J. | last5 = Scheib | first5 = Holger | last6 = Ramjan | first6 = Ryan | last7 = Kuruppu | first7 = Sanjaya | title = Early evolution of the venom system in lizards and snakes. | journal = Nature (Letters) | volume = 439 | pages = 584-588 | year = 2006 | doi = 10.1038/nature04328 }}</ref>

Snakes may have evolved from a common lizard ancestor that was venomous, from which venomous lizards like the ] and ] may have also derived. They share this ] with various other ]n species.

Venomous snakes are classified in two ] ]:
*]s - ]s including ], ]s, ]s, ]s, ]s, and ]s.<ref name="Freiberg84_126"/>
*] - ]s, ]s, ]s/]s, ]s and ]s.<ref name="Freiberg84_126"/>

There is a third family containing the ''opistoglyphous'' (rear-fanged)snakes as well as the majority of other snake species:
*]s - ]s, tree snakes, ]s, ]s, although not all ]s are ].<ref name="Mehrtens87_209"/><ref name="Freiberg84_126"/>

==Interactions with humans==
=== Snake bite ===
{{main|Snakebite}}
]'') can still deliver a deadly bite.]]
Snakes do not ordinarily prey on humans and most will not attack humans unless the snake is startled or injured, preferring instead to avoid contact. With the exception of large constrictors, non-venomous snakes are not a threat to humans. The bite of non-venomous snakes are usually harmless because their teeth are designed for grabbing and holding, rather than tearing or inflicting a deep puncture wound. Although the possibility of an infection and tissue damage is present in the bite of a non-venomous snake; venomous snakes present far greater hazard to humans.<ref name="Mehrtens87_209"/>

Documented deaths resulting from snake bites are uncommon. Non-fatal bites from venomous snakes may result in the need for amputation of a limb or part thereof. Of the roughly 725 species of venomous snakes worldwide, only 250 are able to kill a human with one bite. Although ] is home to the largest number of venomous snakes in the world, it only has one fatal snake bit per year on average. In ], 250,000 snakebites are recorded in a single year with as many as 50,000 recorded initial deaths.<ref name="Sinha">
{{Citation
| last =Sinha
| first =Kounteya
| author-link =
| title = No more the land of snake charmers...
| newspaper = The Times of India
| pages =
| year =2006
| date =25 Jul 2006
| url =http://timesofindia.indiatimes.com/articleshow/1803026.cms }}
</ref>

The treatment for a snakebite is as variable as the bite itself. The most common and effective method is through ], a serum made from the venom of the snake. Some antivenom is species specific (monovalent) while some is made for use with multiple species in mind (polyvalent). In the ] for example, all species of venomous snakes are ]s, with the exception of the ]. To produce antivenin, a mixture of the venoms of the different species of ]s, copperheads, and cottonmouths is injected into the body of a horse in ever-increasing dosages until the horse is immunized. Blood is then extracted from the immunized horse and freeze-dried. It is reconstituted with sterile water and becomes antivenin. For this reason, people who are allergic to horses cannot be treated using antivenin. Antivenin for the more dangerous species (such as ]s, ]s, and ]s) is made in a similar manner in India, South Africa, and Australia with the exception being that those antivenins are species-specific.

===Snake charmers===
{{main|Snake charming}}
] in a basket being charmed]]In some parts of the world, especially in ], ] is a roadside show performed by a charmer. In such a show, the snake charmer carries a basket that contains a snake that he seemingly charms by playing tunes from his flutelike musical instrument, to which the snake responds.<ref name="Bagla"/> Snakes lack external ears, and though they do have internal ears, they show no tendency to be influenced by music.<ref name="Bagla">
{{cite news
| last=Bagla
| first=Pallava
| title=India's Snake Charmers Fade, Blaming Eco-Laws, TV
| date=April 23, 2002
| publisher=National Geographic News
| url=http://news.nationalgeographic.com/news/2002/04/0417_020423_snakecharm_2.html
| accessdate = 2007-11-26}}</ref>

Researchers have pointed out that many of these snake charmers are good sleight-of-hand artists. The snake moves correspondingly to the flute movement and the vibrations from the tapping of the charmer's foot, neither of which is noticed by the public. Charmers rarely catch their snakes and the snakes are either nonvenomous or defanged cobras. Other snake charmers also have a snake and ] show, where both the animals have a mock fight; however, this is not very common, as the snakes, as well as the mongooses, may be seriously injured or killed.

Snake charming as a profession is now discouraged in India as a contribution to forest and snake conservation. In fact, in some places in India snake charming is banned by law.<ref name="Bagla"/>

===Snake trapping===
The tribals of "Irulas" from ] and ] in ] have been hunter-gatherers in the hot dry plains forests and have practiced this art for generations. They have a vast knowledge of snakes in the field. Irulas generally catch the snakes with the help of a simple stick. Earlier, the Irulas caught thousands of snakes for the snake-skin industry. After the complete ban on snake-skin industry in India and protection of all snakes under the ], they formed the Irula Snake Catcher's Cooperative and switched to catching snakes for removal of venom, releasing them in the wild after four extractions. The venom so collected is used for producing life-saving ], biomedical research and for other medicinal products.<ref name="Whitaker et al"> Whitaker, Romulus & Captain, Ashok. ''Snakes of India: The Field Guide''.(2004) pp 11 to 13.</ref> The Irulas are also known to eat some of the snakes they catch and are very useful in rat extermination in the villages.

Despite the existence of snake charmers, there have also been professional snake catchers or wranglers. Modern day snake trapping involves a ] using a long stick with a "V" shaped end. Some like ], ], and ] prefer to catch them using bare hands.
<!--At least one tribe uses a specialized form of snake catching as a rite of passage to manhood.{{Fact|date=February 2007}} The young man of interest will wrap his leg heavily in some type of cloth all the way to the inseam. He will then stick his leg in a burrow containing a large python, typically a ]. After the snake swallows most of his leg several other members of the tribe will pull him out of the hole along with the snake. The snake is then killed and the man's leg removed from the snake. These snakes can be over 20&nbsp;ft long and it is possible for the man to have his leg dislocated. The scent of a prey animal may be used to help convince the snake to swallow the leg. Snakes have a single-track digestive system, but the digestion process is actually much slower.
Commented this para out till the tribe is identified and a reference given/. -->

===Consumption of snakes===
] with a snake]]
While not commonly thought of as a dietary item by most cultures, in some cultures, the consumption of snakes is acceptable, or even considered a delicacy, prized for its alleged pharmaceutical effect of warming the heart. Snake soup of ] is consumed by local people in Autumn, to prevent a cold. Western cultures document the consumption of snakes under extreme circumstances of hunger.<ref>Irvine, F. R. 1954. Snakes as food for man. British Journal of Herpetology. 1(10):183-189.</ref> Cooked rattlesnake meat is an exception, which is commonly consumed in parts of the Midwestern United States. In Asian countries such as ], ], ], ], ] and ], drinking the blood of snakes, particularly the cobra, is believed to increase sexual virility.<ref name="Flynn">
{{cite news
| last=Flynn
| first=Eugene
| title=Flynn Of The Orient Meets The Cobra
| date=April 23, 2002
| publisher=Fabulous Travel
| url=http://www.fabuloustravel.com/gourmet/travel/cobrasblood/cobra.html
| accessdate = 2007-11-26}}</ref> The blood is drained while the cobra is still alive when possible, and is usually mixed with some form of liquor to improve the taste.<ref name="Flynn"/>

In some Asian countries, the use of snakes in alcohol is also accepted. In such cases, the body of a snake or several snakes is left to steep in a jar or container of liquor. It is claimed that this makes the liquor stronger (as well as more expensive). One example of this is the ] snake sometimes placed in the ]n liquor ] also known as "Habu Sake".<ref name="Allen">
{{cite news
| last=Allen
| first=David
| title=Okinawa’s potent habu sake packs healthy punch, poisonous snake
| date=Sunday, July 22, 2001
| publisher=]
| url=http://ww2.pstripes.osd.mil/01/mag/sm072201c.html
| accessdate = 2007-11-26}}</ref>

===Snakes as pets===
In the Western world some snakes, especially docile species such as the ] and ], are kept as pets. To supply this demand a ] industry has developed. Snakes bred in captivity tend to make better pets and are considered preferable to wild caught specimens.

===Symbolism===
] by 16th Century Italian artist ]]]
], symbolize healing.]]
{{main|Serpent (symbolism)}}

In ], the snake occupies a primary role with the Nile cobra adorning the crown of the pharaoh in ancient times. It was ] as one of the gods and was also used for sinister purposes: murder of an adversary and ritual suicide (]).

In ] snakes are often associated with deadly and dangerous antagonists, but this is not to say that snakes are symbolic of evil; in fact, snakes are a ] symbol, roughly translated as 'earthbound'. The nine-headed ] that ] defeated and the three ] sisters are children of Gaia, the earth.<ref name="BF85">Bullfinch (2000) p. 85</ref> ] was one of the three Gorgon sisters who ] defeated.<ref name="BF85"/> Medusa is described as a hideous mortal, with snakes instead of hair and the power to turn men to stone with her gaze.<ref name="BF85"/> After killing her, Perseus gave her head to ] who fixed it to her shield called the ].<ref name="BF85"/> The ] are also depicted in art with snakes instead of legs and feet for the same reason—they are children of Gaia and Ouranos (Uranus), so they are bound to the earth.

Three medical symbols involving snakes that are still used today are ], symbolizing pharmacy, and the ] and ], which are symbols denoting medicine in general.<ref name=AIM>{{cite journal|last=Wilcox|first=Robert A|coauthors=Whitham, Emma M|title=The symbol of modern medicine: why one snake is more than two|date=15 April 2003|url=http://www.annals.org/cgi/content/full/138/8/673|journal=Annals of Internal Medicine|accessdate=2007-12-04}}</ref>

] is often called the land of snakes and is steeped in tradition regarding snakes.<ref name="Deane_61"/> Snakes are worshipped as gods even today with many women pouring ] on snake pits (despite snakes' aversion for milk).<ref name="Deane_61">Deane (1833). p.61</ref> The cobra is seen on the neck of ] and ] is depicted often as sleeping on a 7 headed snake or within the coils of a serpent.<ref>Deane (1833). p.62-64</ref> There are also several temples in India solely for cobras sometimes called ''Nagraj'' (King of Snakes) and it is believed that snakes are symbols of fertility. There is a Hindu festival called ] each year on which day snakes are venerated and prayed to. See also '']''.

In ]{{Fact|date=May 2008}}, ] and ] the snake makes its infamous appearance in the first book (] 3:1) of the ] when a serpent appears before the first couple ] as an agent of the devil and tempts them with the ] from the ]. The snake returns in ] when ], as a sign of God's power, turns his staff into a snake and when Moses made the ], a bronze snake on a pole that when looked at cured the people of bites from the snakes that plagued them in the desert. The serpent makes its final appearance symbolizing ] in the ]:"And he laid hold on the dragon the old serpent, which is the devil and Satan, and bound him for a thousand years." (Revelation 20:2)

The ] is a symbol that is associated with many different religions and customs, and is also claimed to be related to ]. The Ouroboros or Oroboros is a snake eating its own tail in a clock-wise direction (from the head to the tail) in the shape of a circle, representing manifestation of one's own life and rebirth, leading to immortality.

The ] is one of the 12 celestial animals of ], in the ].

Many ancient Peruvian cultures worshipped nature.<ref> Benson, Elizabeth, The Mochica: A Culture of Peru. New York, NY: Praeger Press. 1972</ref> They placed emphasis on animals and often depicted snakes in their art.<ref>Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the ].'' New York: ], 1997.</ref>

===In religion===
].]]
], the prophet of ] was reported to have said to "Kill the snake with two white lines on its back, for it blinds the on-looker and causes ]." <ref>{{Bukhari|4|54|527}}</ref>

Snakes also play a role in the ] faith. The ] was seen as a representative of ] and sly plotting, which can be seen in the description in ] chapter 3 of a snake in the ] tempting ].

Snakes have also been widely revered, such as in ancient Greece, where the serpent was seen as a healer, and Asclepius carried two intertwined on his wand, a symbol seen today on many ambulances. In ], the snake of brass is also a symbol of healing, of one's life being saved from imminent death (] 26:6-9). In Christianity, ]'s redemptive work is compared to saving one's life through beholding the serpent of ] (] 3:14).

In Neo-Paganism and Wicca, the snake is seen as a ] of wisdom and knowledge.

Snakes are part of Hindu worship. Most images of Lord Shiva depict snake around his neck.Puranas have various stories associated with Snakes.

==See also==
] Lima, Peru.]]
'''Snakes'''

* ]
* ]
* ]
* ]
* ]

'''Snakes in culture'''
* ]
* ]
* ]
* ]
* ]
* ]
* ]
* ]

==Cited references==
{{reflist|3}}

==References==
* {{ITIS|ID=174118|taxon=Serpentes|year=2007|date=6 December}}
*{{cite book | last = Bebler | first = John L. | last2 = King | first2 = F. Wayne | title = The Audubon Society Field Guide to Reptiles and Amphibians of North America | publisher = Alfred A. Knopf |Location= New York | pages = 581 | date= 1979 | isbn = 0394508246}}
* {{cite book | last =Bullfinch | first =Thomas | authorlink =Thomas Bullfinch | title =Bullfinch's Complete Mythology
| publisher =Chancellor Press | date =2000 | location =]
| pages =679 | url =http://etext.library.adelaide.edu.au/b/bulfinch/thomas/
| isbn =0753703815 }}
*{{cite book |last= Capula|first= Massimo|coauthors =Behler|title= Simon & Schuster's Guide to Reptiles and Amphibians of the World |year= 1989||publisher= ] |location= ]|isbn= 0671690981}}
*{{cite book |last= Coborn|first= John| title=The Atlas of Snakes of the World| year= 1991| location=]| publisher = TFH Publications| ISBN= 9780866227490}}
*{{cite book | last = Cogger | first = Harold |authorlink = Harold Cogger | last2 = Zweifel | first2 = Richard | title = Reptiles & Amphibians | publisher = Weldon Owen | location = ] |date = 1992 | isbn = 0831727861}}
*{{cite book | last =Conant | first =Roger | last2 =Collins | first2 =Joseph |authorlink=Roger Conant (herpetologist) | title =A Field Guide to Reptiles and Amphibians Eastern/Central North America | publisher =Houghton Mifflin Company | date= 1991 | location =], ] | isbn = 0395583896 }}
*{{cite book | last =Deane | first =John | authorlink =The Worship of the Serpent | title =The Worship of the Serpent | publisher =Kessinger Publishing | date =1833 | location =], ]| pages =412| url =http://www.sacred-texts.com/etc/wos/index.htm | isbn =1564598985 }}
*{{cite book | last =Ditmars | first =Raymond L | authorlink =Raymond Ditmars | title = Poisonous Snakes of the United States: How to Distinguish Them
| publisher =E. R. Sanborn | date =1906 | location =] | pages =11}}
*{{cite book | last =Ditmars | first =Raymond L | authorlink =Raymond Ditmars | title = Snakes of the World | publisher =Macmillian | date =1931
| location =] | pages =11 | isbn = 978-0025317307 }}
*{{cite book | last =Ditmars | first =Raymond L | authorlink =Raymond Ditmars | title = Reptiles of the World: The Crocodilians, Lizards, Snakes, Turtles and Tortoises of the Eastern and Western Hemispheres | publisher =Macmillian | date =1933 | location =] | pages =321}}
*{{cite book | last =Ditmars | first =Raymond L |coauthor = W. Bridges | authorlink =Raymond Ditmars | title = Snake-Hunters' Holiday. | publisher =D. Appleton and Company | date =1935 | location =] | pages =309}}
*{{cite book | last =Ditmars | first =Raymond L | authorlink =Raymond Ditmars | title = A Field Book of North American Snakes | publisher =Doubleday, Doran & Co | date =1939 | location =],] | pages =305}}
*{{cite book |last= Freiberg|first= Dr. Marcos|last2= Walls|first2=Jerry |title= The World of Venomous Animals|year= 1984
|publisher= TFH Publications|location=] |isbn= 0876665679}}
*{{cite book | last =Gibbons | first =J. Whitfield | last2 =Gibbons | first2 =Whit | title =Their Blood Runs Cold: Adventures With Reptiles and Amphibians | publisher =] Press | date =1983 | location =] | pages =164 |isbn=978-0817301354 }}
*{{cite book | last =Mattison | first =Chris | title =The New Encyclopedia of Snakes | publisher =] Press | date =2007 | location =] | pages =272|isbn=978-0691132952 }}
*{{cite book | last=McDiarmid | first=RW | last2= Campbell |first2=JA | last3=Touré| first3=T|year= 1999|title= Snake Species of the World: A Taxonomic and Geographic Reference |volume= 1 |publisher= Herpetologists' League |pages=511 | ISBN= 1893777006 }}
*{{cite book |last= Mehrtens|first= John|title= Living Snakes of the World in Color|year= 1987|publisher= Sterling
|location= ]|isbn= 0806964618}}
*{{cite book | author=] (English edition); Tamil translation by O.Henry Francis | title=நம்மை சுட்ரியுள்ள பாம்புகள் (Snakes around us, Tamil) | publisher=National Book Trust | year=1996 | id=ISBN 81-237-1905-1}}
*{{cite book |last = Rosenfeld | first = Arthur | title = Exotic Pets | publisher = ] | location= ] | date= 1989 | pages=293|isbn = 067147654}}
*{{cite book |last =Spawls| first=Steven|last2 =Branch |first2= Bill |year= 1995 |title= The Dangerous Snakes of Africa |publisher=Ralph Curtis Publishing| location=],]|pages= 192 |isbn = 0883590298}}

==External links==
{{commonscat|Serpentes}}
* (USDA)
*
*
*
*
* (INDIA)
*
* (OPLIN)
*
*

{{Snake_families}}

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Revision as of 16:26, 23 June 2008