Caspian cobra
| Caspian cobra | |
|---|---|
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| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Elapidae |
| Genus: | Naja |
| Species: | N. oxiana |
| Binomial name | |
| Naja oxiana (Eichwald, 1831)[2] |
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The Caspian cobra (Naja oxiana), also called the Central Asian cobra is a species of venomous snake in the family Elapidae found in Central Asia.
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[edit] Description
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This species is medium to large in length, heavy bodied snake with long cervical ribs capable of expansion to form a hood. The body is compressed dorsoventrally and subcylindrical posteriorly. This species averages about 1 metre (3.3 ft)[3] in length and rarely reaches lengths over 1.5 metres (4.9 ft).[4] The head is elliptical, depressed, slightly distinct from the neck with a short, rounded snout and large nostrils. The eyes are medium in size with round pupils. Dorsal scales are smooth and strongly oblique with the outer two or three scale rows larger than the remainder.[3] Juveniles tend to be pale, with a faded appearance. They have noticeable dark and light cross-bands of approximately equal width around the body. Adults of this species are completely light to chocolate brown or yellowish, some retain traces of juvenile banding, especially the first few dark ventral bands. This species has no hood mark and no lateral throat spots.[4]
[edit] Taxonomic note
Indian cobra (Naja naja) specimens without a hood mark are usually confused with this species, where these two co-exist in Pakistan and northern India. The Caspian cobra is never fully black, although some specimens may be quite dark. Another thing is that this species of cobra normally has several dark bands under the throat, whereas in the black phase of Indian cobras (N. naja) from Pakistan, almost the entire throat is black.[5]
[edit] Scalation
23-27 (usually 25) scale rows around hood, 19-23 (usually 21) just ahead of midbody; 191-210 ventrals, 57-71 paired subcaudals; cuneates often absent.[4]
[edit] Distribution
This species is occurs in the Transcaspian Region. It is found in Turkmenistan, Uzbekistan, Kyrgyzstan, Tadzhikistan, north and east Afghanistan, northeastern Iran, the northern half of Pakistan, from the Kashmir region east to the state of Himachal Pradesh in India, and in southwestern Tajikistan.[3][4]
[edit] Habitat
This species is often found in arid and semi-arid, rocky or stony, shrub or scrub covered foothills[3] at elevations up to about 3,000 metres (9,800 ft). This is also the westernmost species of Asiatic cobra.[6]
[edit] Behavior and ecology
This species generally has a mild disposition and always looks for an escape when encountered (juveniles tend to be more aggressive). If cornered and provoked, however, it will spread its hood, hiss, sway from side to side and strike repeatedly. This is not a spitter. This is a terrestrial species that is mainly diurnal but it may be crepuscular and nocturnal in some parts of its range during the hottest months (July and August). It is a good climber and a good swimmer. It is particularly fond of water and seldom found too far away from it. It feeds on small mammals, amphibians and birds during the evening and early morning. The Caspian cobra will prey mainly on rodents, toads and frogs, occasionally fish, birds and their eggs.[3] It is a quick-moving and agile species that lives in holes in embankments or trees.[6]
[edit] Venom
The venom is primarily a potent neurotoxin,[6] but it also has some cytotoxic activity (tissue-death; necrosis).[7] Two forms of "cytotoxin II" (cardiotoxin) were found in the venom of this species.[8] The SC LD50 value is 0.4 mg/kg, making it one of the most venomous of the Naja (cobra) species.[9] The bite of this species may cause severe pain and swelling. Weakness, drowsiness and paralysis of throat may appear in less than one hour after the bite. Without medical treatment, symptoms rapidly worsen and death can rapidly occur after a bite due to respiratory failure.[6]
[edit] See also
[edit] References
- ^ "Naja oxiana". The IUCN Red List of Threatened Species. http://www.iucnredlist.org. http://www.iucnredlist.org/apps/redlist/details/164642/0. Retrieved 13 January 2012.
- ^ "Naja oxiana". ITIS Standard Report Page. ITIS.gov. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=700635. Retrieved 13 January 2012.
- ^ a b c d e "Naja oxiana - General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid, Antivenoms". WCH Clinical Toxinology Resource. University of Adelaide. http://www.toxinology.com/fusebox.cfm?fuseaction=main.snakes.display&id=SN0042. Retrieved 13 January 2012.
- ^ a b c d "Species of Asiatic Naja". The Asiatic Cobra Systematics Page. Bangor University. http://pages.bangor.ac.uk/~bss166/Taxa/AsNaja.htm. Retrieved 13 January 2012.
- ^ "Venom Street (Naja oxiana)". Venom Street Collector and Breeder of Asian Cobras. Venom Street. http://www.venomstreet.com/Naja%20oxiana.htm. Retrieved 3 February 2012.
- ^ a b c d "Naja oxiana". Armed Forces Pest Management Board. United States Department of Defense. http://www.afpmb.org/content/venomous-animals-n#Najaoxiana. Retrieved 14 January 2012.
- ^ Feofanov, AV; Sharonov GV, Astapova MV, Rodionov DI, Utkin YN, Arseniev AS (15). "Cancer cell injury by cytotoxins from cobra venom is mediated through lysosomal damage". The Biochemical Journal 390 (1): 11-18. PMID 15847607. http://www.ncbi.nlm.nih.gov/pubmed/15847607. Retrieved 13 January 2012.
- ^ Dementieva, DV; Bocharov EV, Arseniev AS (July 1999). "Two forms of cytotoxin II (cardiotoxin) from Naja naja oxiana in aqueous solution: spatial structures with tightly bound water molecules". European Journal of Biochemistry 263 (1): 152-162. PMID 10429199. http://www.ncbi.nlm.nih.gov/pubmed/10429199. Retrieved 3 February 2012.
- ^ Brown Ph.D, John H. (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, IL USA: Charles C. Thomas Publishers. pp. 82. ISBN 0-398-02808-7.
[edit] Further reading
- Wüster, Wolfgang (1993) A century of confusion: Asiatic cobras revisited. Vivarium, 4(4):14-18
- Eichwald, E (1831) Zoologia specialis, quam expositis animalibus tum vivis, tum fossilibus potissimuni rossiae in universum, et poloniae in specie, in usum lectionum publicarum in Universitate Caesarea Vilnensi. Zawadski, Vilnae.
- Wüster, W and Thorpe, RS (1991) Asiatic cobras: Systematics and snakebite. Experientia, 47:205-209.
- Wüster, W and Thorpe, RS (1992) Asiatic cobras: population systematics of the Naja naja species complex (Serpentes: Elapidae) in India and Central Asia. Herpetologica, 48:69-85.
- Wüster, Wolfgang (1998) The cobras of the genus Naja in India. Hamadryad, 23(1):15-32.
