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Indian cobra

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Indian Cobra
Naja naja with hood spread open
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Reptilia
Order:
Squamata
Suborder:
Serpentes
Family:
Elapidae
Genus:
Naja

Laurenti, 1768
Species:
N. naja
Binomial name
Naja naja
(Linnaeus, 1758)[1]
Synonyms

Coluber naja Linnaeus, 1758
Naja fasciata Laurenti, 1768
Vipera naja Daudin, 1803
Naja tripudians Gray, 1834
Naia tripudians Boulenger, 1896

Indian Cobra (Naja naja) or Spectacled Cobra is a species of the genus Naja found in the Indian subcontinent and a member of the "big four", the four species which inflict the most snakebites in India.[2] This snake is revered in Indian mythology and culture, and is often seen with snake charmers. It is now protected in India under the Indian Wildlife Protection Act (1972).

Etymology and names

Naja naja was first described by Swedish zoologist Carl Linnaeus in 1758.[1] The generic and specific epithet name naja is a Latinisation of the Sanskrit word nāgá (नाग) meaning "cobra".

The Indian Cobra[3][4] or Spectacled Cobra,[2] being common in South Asia, is referred to by a number of local names deriving from the root of Naag (Hindi, Sanskrit, Oriya, Marathi), Moorkan (Malayalam), Naya (Singhalese), Naagu Pamu (Telugu),[4] Nagara Haavu (Kannada),[4] Naaga Pambu or Nalla pambu (Tamil)[4] and Gokhra (Bengali).

Description

Spectacle pattern on a snake's hood

The Indian cobra is a medium to large, heavy bodied snake with long cervical ribs capable of expansion to form a hood when threatened. The body is compressed dorsoventrally and subcylindrical posteriorly. It can grow to a maximum of about 2.4 metres (7.9 ft) in length, but averages between 1.8 and 2.2 metres (5.9 and 7.2 ft) long. The head is elliptical, depressed, very 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.[5] On the rear of the snake's hood are two circular ocelli patterns connected by a curved line, evoking the image of spectacles. Hindus believe them to be the footmarks of Krishna, who danced on Kāliyā, the hundred and ten hooded snake's head. The Indian Cobra's most known characteristic features are the wide black band on the underside of the neck, and the hood marking design which shows half-rings on either side of the hood. It is a smooth-scaled snake with black eyes, a wide neck and head, and a medium-sized body. Its colouring varies from black, to dark brown, to a creamy white. The body is usually covered with a spectacled white or yellow pattern, which sometimes forms ragged bands.[6] The spectacle pattern on the hood varies greatly, as does the overall colour of the snake.[7]

The Oriental Ratsnake Ptyas mucosus is often mistaken for the cobra; however this snake is much longer and can easily be distinguished by the more prominent ridged appearance of its body. Other snakes that resemble Naja naja are the Banded Racer Argyrogena fasciolata and the Indian Smooth Snake Coronella brachyura.

Scalation

171-197 ventrals, 50-67 subcaudals, all divided; dorsal scale row counts very variable; except in north-west, very high dorsal scale row counts (23-25 just ahead of mid-body, 29-37 around the hood); north-western specimens have 23-27 scale rows around the hood and 19-21 ahead of mid-body.[7]

Distribution, habitat and ecology

The Indian cobra is native to the Indian subcontinent which includes present day Pakistan, India, Bangladesh and Sri Lanka. It can be found in plains, jungles, open fields and the regions heavily populated by people. Its distribution ranges from sea-level up to 2,000 metres (6,600 ft) above sea-level. The Indian cobra feeds on rodents, lizards and frogs. It bites quickly, and then waits while its venom damages the nervous system of the prey, paralyzing and often killing it. Like all snakes, N. naja swallows its prey whole. This species sometimes enters buildings in search of rodent prey.[6]

Reproduction

The Indian Cobra reproduces sexually by the joining of male and female gametes and produces eggs. Eggs between the months of April and July. The female snake usually lays between 12 to 20 eggs in rat holes or termite mounds. The female will guard the eggs throughout the incubation period, only leaving to feed. The eggs hatch approximately 50 days later. The hatchlings measure between 20 and 30 centimetres (7.9 and 11.8 in) in length. The hatchlings are independent from birth and have fully functional venom glands.[8][9]

Venom

The Indian cobra's venom mainly contains a powerful post-synaptic neurotoxin [10] and cardiotoxin.[10][11] The venom acts on the synaptic gaps of the nerves, thereby paralyzing muscles, and in severe bites leading to respiratory failure or cardiac arrest. The venom components include enzymes such as hyaluronidase that cause lysis and increase the spread of the venom. Envenomation symptoms may manifest between 15 minutes to 2 hours following the bite and can be fatal in an hour in severe cases of envenomation.[12]

In mice, the SC LD50 range for this species is 0.57 mg/kg[10] - 0.80 mg/kg.[13] The average venom yield per bite is between 169 —250 mg.[10] Mortality rate for untreated bite victims can vary tremendously, but according to one study it is approximately 15-20%.[14] Another study with 1,224 bite cases the mortality rate was only 6.5%.[13]

The Indian cobra is one of the Big four snakes of South Asia (mostly India) which are responsible for the majority of human deaths by snakebite in Asia. Polyvalent serum is available for treating snakebites caused by this species.[15] Zedoary, a local spice with a reputation for being effective against snakebite,[16] has shown promise in experiments testing its activity against cobra venom.[17]

The venom of young cobras has been used as a substance of abuse in India, with cases of snake charmers being paid for providing bites from their snakes. Though this practice is now seen as outdated, symptoms of such abuse include loss of consciousness, euphoria, and sedation.[18]

Hindu culture

Cobra in a basket, raising its head and spreading its hood.

The spectacled cobra is much respected and feared, and even has its own place in Hindu mythology as a powerful deity. The Hindu god Shiva is often depicted with a protective cobra coiled around his neck. Vishnu, the preserver of the universe, is usually portrayed as reclining on the coiled body of Sheshnag, the Preeminent Serpent, a giant snake deity with multiple cobra heads. Cobras are also worshipped during the Hindu festival of Nag Panchami.

There are numerous myths about cobras in India, including the idea that they mate with ratsnakes.[19]

Snake charming

The Indian cobra's celebrity comes from its popularity as a snake of choice for snake charmers. The cobra's dramatic threat posture makes for a unique spectacle as it appears to sway to the tune of a snake charmer's flute. Snake charmers with their cobras in a wicker basket are a common sight in many parts of India only during the Nag Panchami festival. The cobra is deaf to the snake charmer's pipe, but follows the visual cue of the moving pipe and it can sense the ground vibrations from the snake charmer's tapping. In the past Indian snake charmers also conducted cobra and mongoose fights. These gory fight shows, in which the snake was usually killed, are now illegal.[20]

References

Wikimedia Commons has media related to Naja naja.
  1. ^ a b "Naja naja". ITIS Standard Report Page. ITIS.gov. Retrieved 3 March 2012.
  2. ^ a b Whitaker, Romulus & Captain, Ashok (2004) Snakes of India: The Field Guide
  3. ^ Smith, Malcolm A. (1942) The Fauna of British India - Vol III (Serpentes), pp 427-436.
  4. ^ a b c d Daniels, J. C. (2002) The Book of Indian Reptiles and Amphibians, BNHS & Oxford University Press, Mumbai, pp 136-140.
  5. ^ "Naja naja: General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid, Antivenoms". Clinical Toxinology Resource. University of Adelaide. Retrieved 3 March 2012.
  6. ^ a b "Indian cobra". Animal Diversity Web. University of Michigan (Museum of Zoology). Retrieved 3 March 2012.
  7. ^ a b "Species of Asiatic Naja". Asiatic Naja. Bangor University. Retrieved 3 March 2012.
  8. ^ Breen, JF (1974). Encyclopedia of Reptiles and Amphibians. USA: Tfh Pubns Inc. ISBN 0876662203.
  9. ^ Burton, John A. (1991). Book of Snakes. United States: Gramercy. ISBN 0517060930.
  10. ^ a b c d "Clinical Toxinology Resources-Naja naja".
  11. ^ Achyuthan, K. E. and L. K. Ramachandran(1981) Cardiotoxin of the Indian cobra (Naja naja) is a pyrophosphatase. J. Biosci. 3(2):149-156 PDF
  12. ^ "IMMEDIATE FIRST AID for bites by Indian or Common Cobra(Naja naja naja)".
  13. ^ a b Brown Ph.D, John H. (1973). Toxicology and Pharmacology of Venoms from Poisonous Snakes. Springfield, IL USA: Charles C. Thomas Publishers. p. 81. ISBN 0-398-02808-7.
  14. ^ World Health Organization. "Zoonotic disease control: baseline epidemiological study on snake-bite treatment and management". Weekly Epidemiological Record (WER). 62 (42): 319–320. ISSN 0049-8114.
  15. ^ BBC (Snake-bites: a growing, global threat)
  16. ^ Martz W (1992). "Plants with a reputation against snakebite". Toxicon. 30 (10): 1131–1142. doi:10.1016/0041-0101(92)90429-9. PMID 1440620. {{cite journal}}: Unknown parameter |month= ignored (help)
  17. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.ab.2005.03.037 , please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.ab.2005.03.037 instead.
  18. ^ [1], Katshu, Mohammad Zia Ul Haq , Dubey, Indu , Khess, C. R. J. and Sarkhel, Sujit (2011) 'Snake Bite as a Novel Form of Substance Abuse: Personality Profiles and Cultural Perspectives', Substance Abuse, 32:1, 43 - 46
  19. ^ http://www.wildlifesos.com/rprotect/snakemyths.htm Snake myths
  20. ^ http://www.indialawinfo.com/bareacts/pca.html Prevention of Cruelty to Animals Act 1960
  • Daniel, J.C. (2002). The Book of Indian Reptiles and Amphibians. Oxford, England: Bombay Natural History Society and Oxford University Press. ISBN 0-19-566099-4.[clarification needed]
  • Smith, M.A. (1943). "The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-Region". Reptilia and Amphibia. 3 (Serpentes). London, England: Taylor and Francis.[clarification needed]
  • Whitaker, Romulus (2004). Snakes of India: The Field Guide. Chennai, India: Draco Books. ISBN 81-901873-00-9. {{cite book}}: Check |isbn= value: length (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)[clarification needed]


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