Indian cobra
Indian cobra | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Elapidae |
Genus: | Naja |
Species: | N. naja
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Binomial name | |
Naja naja | |
Indian cobra distribution | |
Synonyms[3][5] | |
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The Indian cobra (Naja naja), also known commonly as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of cobra, a venomous snake in the family Elapidae. The species is native to the Indian subcontinent, and is a member of the "big four" species that are responsible for the most snakebite cases in India.[6][7]
It is distinct from the
Taxonomy
The
The Indian cobra is classified under the genus
Naja naja is considered to be the prototypical cobra species within the subgenus Naja, and within the entire genus Naja. All Asiatic species of Naja were considered conspecific with Naja naja until the 1990s, often as subspecies thereof. Many of the subspecies were later found to be artificial or composites. This causes much potential confusion when interpreting older literature.[11]
Naja |
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Local names
The Indian cobra[12][13] or spectacled cobra,[6] being common in South Asia, is referred to by a number of local names deriving from the root of Naga.
For Indo-Aryan and Dravidian languages:
- Phetigom (ফেতিগোম) in Assamese
- Gokhra (গোখরো) in Bengali
- Naag (नाग) in Hindi,
- Fetaar (फेटार) in Awadhi
- Gehuan (गेहुंअन)in Magahi and Bhojpuri
- Domi (डोमी) in Chhattisgarhi
- Naag (નાગ) in Gujarati
- Nagara Haavu (ನಾಗರ ಹಾವು) in Kannada
- Moorkkan (മൂര്ഖന്) in Malayalam
- Naag (नाग) in Marathi
- Gokhara Saapa (ଗୋଖର ସାପ) or Naaga Saapa (ନାଗ ସାପ) in Odia
- Naya (නයා) or Nagaya (නාගයා) in Sinhalese
- Nalla pambu (நல்ல பாம்பு) or Nagapambu (நாகப்பாம்பு) in Tamil
- Nagu Paamu(నాగు పాము) in Telugu
- Saanp ( سانپ/sɑ̃ːp/) in Urdu
- "Uchchu" (Tulu Language)
Description
The Indian cobra is a moderately sized, heavy-bodied species. This cobra species can easily be identified by its relatively large and quite impressive hood, which it expands when threatened.
Many specimens exhibit a hood mark. This hood mark is located at the rear (
This species has a head which is elliptical, depressed, and very slightly distinct from the neck. The snout is short and rounded with large nostrils. The eyes are medium in size and the pupils are round.[15] The majority of adult specimens range from 1 to 1.5 metres (3.3 to 4.9 ft) in length. Some specimens, particularly those from Sri Lanka, may grow to lengths of 2.1 to 2.2 metres (6.9 to 7.2 ft), but this is relatively uncommon.[14]
The Indian cobra varies tremendously in colour and pattern throughout its range. The ventral scales or the underside colouration of this species can be grey, yellow, tan, brown, reddish or black. Dorsal scales of the Indian cobra may have a hood mark or colour patterns. The most common visible pattern is a posteriorly convex light band at the level of the 20th to 25th ventrals. Salt-and-pepper speckles, especially in adult specimens, are seen on the dorsal scales.
Specimens, particularly those found in Sri Lanka, may exhibit poorly defined banding on the dorsum.
Patterns on the throat and ventral scales are also variable in this species. The majority of specimens exhibit a light throat area followed by dark banding, which can be 4–7 ventral scales wide. Adult specimens also often exhibit a significant amount of mottling on the throat and on the venter, which makes patterns on this species less clear relative to patterns seen in other species of cobra. With the exception of specimens from the northwest, there is often a pair of lateral spots on the throat where the ventral and dorsal scales meet. The positioning of these spots varies, with northwestern specimens having the spots positioned more anterior, while specimens from elsewhere in their range are more posterior.
Scalation
Dorsal scales are smooth and strongly oblique. Midbody scales are in 23 rows (21–25), with 171–197
Similar species
The Oriental rat snake
Distribution and habitat
The Indian cobra is native to the
The Indian cobra inhabits a wide range of habitats throughout its geographical range. It can be found in dense or open forests, plains, agricultural lands (rice paddy fields, wheat crops), rocky terrain, wetlands, and it can even be found in heavily populated urban areas, such as villages and city outskirts, ranging from sea level to 2,000 metres (6,600 ft) in altitude. This species is absent from true desert regions. The Indian cobra is often found in the vicinity of water. Preferred hiding locations are holes in embankments, tree hollows, termite mounds, rock piles and small mammal dens.[15][18]
Reproduction
Indian cobras are
Venom
The Indian cobra's venom mainly contains a powerful post-
In
The Indian cobra is one of the
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.[30]
As of November 2016[update], an antivenom is currently being developed by the Costa Rican Clodomiro Picado Institute, and the clinical trial phase is in Sri Lanka.[31]
Envenomation and clinical manifestation
Indian cobras (N. naja) earliest clinical manifestation of systemic envenoming was drowsiness, which occurred in 60% of cases starting at 30 minutes (severe bites) post-envenomation to 3 hours post bite. Difficulty in opening the eyes, speaking, opening the mouth, moving the lips and swallowing followed 1 – 4 hours later. Ptosis developed 1.6 – 6 hours post bite in all cases of systemic envenoming. General weakness was usually the last symptom to develop, followed by paralysis of the muscles in severe cases. Three patients developed respiratory paralysis and were given artificial respiration; 2 recovered and 1 died. The fatal case developed respiratory paralysis about 10 minutes before reaching hospital and patient became comatose; tracheostomy and artificial respiration were performed immediately and antivenom was administered intravenously. Patient survived for 8 days but finally died. The outstanding feature of systemic envenoming is paralysis of the muscles due to rapid action of neurotoxin at the myoneural junction. Respiratory paralysis may occur within 3 – 4 hours in severe cases.
Indian cobra bites are very common in many parts of India, Pakistan, Sri Lanka, and throughout their range in South Asia. Hundreds of individual case reports have been published in books and journals over the past century. It is astonishing, however, that no large prospective study of patients with proven bites by N. naja has been undertaken and reported. In a survey of snakebites in India, 91.4% of cases were bitten by an unidentified snake. Of the 6.1% of identified venomous snakes responsible for bites, 40% were N. naja. As with bites by N. kaouthia and N. oxiana, patients may show manifestations of systemic neurotoxic envenoming or local envenoming or both, although N. oxiana bites produce noticeable symptoms of envenomation more rapidly and prominent neurotoxicity (severe flaccid paralysis) is more common amongst patients bitten by N. oxiana. A woman bitten by N. oxiana in northwestern Pakistan suffered prominent neurotoxicity and died while en route to the closest hospital nearly 50 minutes after envenomation (death occurred 45–50 minutes post envenomation).[32]
Local necrosis was described after cobra bites in India in the 1860s and up to the 1920s but this was apparently forgotten until Reid's work in Malaysia. Severe local pain and swelling may begin almost immediately after the bite. The pain persists while swelling and tenderness extend up the bitten limb, sometimes spreading to the adjacent trunk. Darkening of the necrotic area of skin and blistering are apparent by about the third day with a characteristic putrid smell typical of necrotic cobra bites in Africa and Asia. Early systemic symptoms include headache, nausea, vomiting, dizziness and a feeling of lassitude, drowsiness and intoxication. "Many subjects describe their drowsiness as if they had imbibed large quantities of some potent intoxicant." Neurotoxic symptoms begin with ptosis (the patient puckers their brow, contracting the frontalis muscle, attempting to raise the eyelids or tilts the head back so as to see beneath the drooping upper lids), profuse viscid saliva, inability to clear secretions, sagging of the jaw or inability to open the mouth and progression to respiratory paralysis. It is not clear from the available literature whether the proportion of patients developing neurotoxicity and necrosis is different from that in patients bitten by N. kaouthia.[33]
Between 1968 - 1974, clinical observations were made on 20 cases of cobra bites in Thailand. Most of the patients came from the rural health centres and the cobra responsible for the bite was identified as Naja naja (Indian cobra). All 20 patients developed systemic envenoming. Antivenom for cobra bite was administered intravenously together with symptomatic and supportive treatment; 19 patients survived and 1 died from cerebral anoxia.[34]
The outstanding feature of systemic envenoming is paralysis of the muscles due to rapid action of neurotoxin at the myoneural junction.
Genome
Previous cytogenetic analysis revealed the Indian cobra has a diploid
Synteny analysis
Synteny analysis between the Indian cobra and the prairie rattlesnake genome revealed large syntenic blocks within macro, micro, and sexual chromosomes. This study allowed the observation of chromosomic fusion and fission events that are consistent with the difference in chromosome number between these species. For example, chromosome 4 of the Indian cobra shares syntenic regions with chromosomes 3 and 5 of the rattlesnake genome, indicating a possible fusion event. Besides, chromosomes 5 and 6 of the Indian cobra are syntenic to rattlesnake chromosome 4, indicating a possible fusion event between these chromosomes.[36]
On the other hand, by performing whole-genome synteny comparison between the Indian cobra and other reptilian and avian genomes, it was revealed the presence of large syntenic regions between macro, micro, and sexual chromosomes across species from these classes, which indicates changes in chromosome organization between reptile and avian genomes and is consistent with their evolutionary trajectories.[36]
Gene organization
Using protein homology information and expression data from different tissues of the cobra, 23,248 protein-coding genes, 31,447 transcripts, and 31,036 proteins, which included alternatively spliced products, where predicted from this genome. 85% of these predicted proteins contained start and stop codon, and 12% contained an N-terminal secretion signal sequence, which is an important feature in terms of toxins secretion from venom glands.[36]
Venom gland genes
Further studies on gene prediction and annotation of the Indian cobra genome identified 139 toxin genes from 33 protein families. These included families like
Venom gland transcriptome and toxin gene identification
Analysis of transcriptomic data from 14 different tissues of the Indian cobra identified 19,426 expressed genes. Out of these genes, 12,346 belonged to the venom gland transcriptome, which included 139 genes from 33 toxin gene families. Additionally, differential expression analysis revealed that 109 genes from 15 different toxin gene families were significantly up-regulated (fold change > 2) in the venom gland and this included 19 genes that were exclusively expressed in this gland.[36]
These 19 venom specific toxins (VSTs) encode the core effector toxin proteins and include 9 three-finger toxins (out of which six are
This transcriptomic data together with the information provided by the high quality Indian cobra genome generated by Susyamohan et al., 2020 suggest that these VSTs together with AVPs form the core toxic effector components of this venomous snake, which induce muscular paralysis, cardiovascular dysfunction, nausea, blurred vision and hemorrhage after snake bite.[36][37]
The identification of these genes coding for core toxic effector components from the Indian cobra venom may allow the development of recombinant antivenoms based in neutralizing antibodies for VST proteins.[36]
Popular culture
There are numerous myths about cobras in India, including the idea that they mate with rat snakes.[38]
Rudyard Kipling's short story "Rikki-Tikki-Tavi" features a pair of Indian cobras named Nag and Nagaina, the Hindi words for male and female snake, respectively.
Hinduism
The Indian cobra is often featured in
Snake charming
The Indian cobra's celebrity comes from its popularity with
Heraldry
Indian cobras were often a heraldic element in the official symbols of certain ancient princely states of India such as Gwalior, Kolhapur, Pal Lahara, Gondal, Khairagarh and Kalahandi, among others.[40]
Gallery
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Indian cobra displaying an impressive hood
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Albino spectacled cobra
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Binocellate cobra
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Cobra regurgitating
References
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- ^ ISBN 81-901873-0-9.
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- ^ "Naja". Integrated Taxonomic Information System. Retrieved 29 March 2014.
- ^ Linnaeus, Carl (1758). Systema naturae per regna tria naturae :secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis (in Latin) (10th ed.). Stockholm: Laurentius Salvius. Archived from the original on 2008-10-10. Retrieved 2018-01-13.
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- ^ Smith, M.A. (1943). Reptilia and Amphibia, Volume 3: Serpentes. The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-Region. London, England: Taylor and Francis. pp. 427–436.
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- ^ a b c Wüster, W. (1998). "The Cobras of the genus Naja in India" (PDF). Hamadryad. 23 (1): 15–32. Archived from the original (PDF) on 4 March 2016. Retrieved 15 September 2014.
- ^ a b c d e f g h "Naja naja". University of Adelaide. Archived from the original on 2014-12-08. Retrieved 2011-11-10.
- ^ "Naja oxiana". Venom Street. Collector and Breeder of Asian Cobras. Venom Street. Archived from the original on 21 October 2014. Retrieved 3 February 2012.
- ^ Mahendra, BC. (1984). Handbook of the snakes of India, Ceylon, Burma, Bangladesh and Pakistan. Agra : The Academy of Zoology. p. 412.
- ^ ISBN 81-901873-0-9.)
{{cite book}}
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- ^ "Immediate First Aid for bites by Indian or Common Cobra (Naja naja naja)". Archived from the original on 2012-04-02.
- ^ "LD50". Séan Thomas & Eugene Griessel – Dec 1999;Australian Venom and Toxin database. University of Queensland. Archived from the original on February 1, 2012. Retrieved 1 December 2011.
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- ^ Snake-bites: a growing, global threat Archived 2011-11-13 at the Wayback Machine. BBC News (2011-02-22). Retrieved on 2013-01-03.
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- ^ Rodrigo, M. (October 9, 2016) Trials to start for home-grown anti-venom Archived 2016-10-14 at the Wayback Machine. sundaytimes.lk
- ISBN 978-0-916984-22-9. (Naja naja oxiana, Ladle Snake, p. 124).
- ^ ISBN 9780203719442. Archivedfrom the original on 24 May 2021. Retrieved 14 July 2021.
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- ^ Prevention of Cruelty to Animals Act 1960. indialawinfo.com
- ^ Heraldry of Madhya Pradesh Archived 2015-12-22 at the Wayback Machine. hubert-herald.nl
External links
- Serpents in Indian culture An article on Biodiversity of India website.