Overview

Brief Summary

The dangerously venomous Monocled Cobra (Naja kaouthia) occurs in Myanmar, Nepal, Bangladesh, northeastern India (Assam), Thailand (in wetter areas), northern Malaysia, Cambodia, southern Laos and southern Vietnam, and southwestern China (Sichuan, Yunnan). Leviton et al. (2003) report that in Myanmar this species is widely distributed in wetter habitats, occurring in Ayeyarwady Division, Chin State, Kachin State, Magway Division [part], Rakhine State, Sagaing Division [part], and Yangon Division. (In the drier central region of Myanmar, in dry and moist deciduous forests spanning Mandalay, Magway [part], and Sagaing [part] Divisions, this species is replaced by Naja mandalayensis.)

Naja kaouthia is often encountered in villages, agricultural areas, and grasslands as well asin  primary coastal rainforest. It can be found swimming in lakes and rivers as well as beneath rocks and in the burrows of other animals. Individuals have been observed climbing trees. In Myanmar, N. kaouthia has beed recorded from sea level to 820 m. Although most active at dusk and at night, these snakes can be active during the day as well. (Leviton et al. 2003)

Leviton et al. (2003) provide a technical description of this Naja kaouthia: Body scales smooth, arranged in 19-21 (usually 21) longitudinal rows at midbody; throat pale with little dark mottling, often followed by a single dark band; ventrolateral throat spots distinct; remainder of venter either pale or increasingly cloudy with darker pigmentation toward the rear. In adults, hood markings usually distinct, typically pale, oval or circular with a dark center (occasionally with a narrow dark outer border); occasionally one or two dark spots are present within the pale oval. Fangs are not modified for spitting, venom discharge orifice is large. Ventrals 164-196; subcaudals 43-58. Total length 1500 mm, tail 300 mm  (possibly larger specimens, but rare).

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Distribution

Range Description

This species occurs from northeastern India, Bangladesh and Bhutan across southern China, southward to northern Peninsular Malaysia (Wster 1996). It is absent from the central dry zone of Myanmar. Its presence in northern Lao PDR has not been confirmed although it has been recorded from the southern part of the country. It is absent from North Viet Nam, where records attributed to this species likely reflect confusion with N. atra or N. siamensis.
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Continent: Asia
Distribution: Bangladesh, Myanmar (= Burma), Cambodia, NE India (Uttar Pradesh, Bihar, Sikkim, Assam, West Bengal, Orissa), Laos, N Malaysia, Nepal (?), S China, Thailand, S Vietnam  
Type locality: Bengal [India]
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
This species can adapt to a range of habitats, including both natural and anthropogenically-modified environments. It prefers habitats associated with water, such as paddy fields, swamps, and mangroves, but can also be found in grasslands, shrublands, and forests. It also occurs in agricultural land and human settlements, including cities. It occurs up to 1,000 m elevation.

Systems
  • Terrestrial
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Life History and Behavior

Life Expectancy

Lifespan, longevity, and ageing

Maximum longevity: 25.4 years (captivity)
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
Stuart, B. & Wogan, G.

Reviewer/s
Bowles, P. & Cox, N.A.

Contributor/s
Zug, G., De Silva, R., Milligan, HT, Wearn, O.R., Wren, S., Zamin, T., Sears, J., Wilson, P., Lewis, S., Lintott, P. & Powney, G.

Justification
Naja kaouthia has been assessed as Least Concern owing to its large distribution, tolerance of a broad range of modified habitats, and its reported abundance. No major threats have been reported although it is extensively used for food, snake wine, skin trade and medicinal purposes, and has undergone at least localized population declines in the eastern part of its range. For this reason it is listed in appendix II of CITES. However, it is not known whether it is undergoing a significant population decline and more research is needed to establish whether this species might warrant reassessment.

History
  • 2010
    Least Concern (LC)
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Population

Population
This species is common in most of its range. G. Zug (pers. comm.) states that it is widespread and common in Myanmar. It is also fairly common in Indochina. It is considered to have declined by over 30% over the preceding ten years in China as a result of overharvesting (Wang and Xie 2009), although China forms a small part of its range. It is explicitly included within the concept of Naja naja that the Viet Nam Red Data Book estimates has suffered a 50% population decline over the same period (Dang et al. 2007), but rates of decline specifically attributable to this species in Viet Nam are unknown. It is unclear whether this species is undergoing significant declines elsewhere within its range.

Population Trend
Decreasing
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Threats

Major Threats
The species is probably threatened in China, Myanmar and much of Indochina, as a result of heavy exploitation for use in traditional medicine, including snake wine in Viet Nam, and for skins and food. CITES data indicates, however, that it is unclear whether these pressures are sufficient to threaten the survival of subpopulations.
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Management

Conservation Actions

Conservation Actions
This species is listed on CITES Appendix II. Its large geographic distribution is coincident with a number of protected areas. As part of the Naja naja complex (with N. naja, N. atra and N. siamensis), this species is protected in Vietnam (where members of the complex are listed as nationally Endangered - Dang et al. 2007) by government decree, limiting commercial exploitation. The China Species Red List lists this snake as nationally Vulnerable (Wang and Xie 2009). Due to its extensive use more research on how harvesting is impacting the population in major areas of its range is recommended.
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Wikipedia

Monocled cobra

The monocled cobra (Naja kaouthia), also called monocellate cobra, is a cobra species, which is widespread across South and South East Asia and listed as Least Concern by IUCN.[1]

Taxonomic history[edit]

In 1831, René Lesson first described the monocled cobra as a beautiful snake that is well distinct from the spectacled cobra, with 188 ventral scales and 53 pairs of caudal scales.[2]

Since then, several monocled cobras were described under different scientific names:

Several varieties of monocled cobras were described under the binomial Naja tripudians between 1895 and 1913.

  • Naja tripudians var. scopinucha 1895
  • Naja tripudians var. unicolor 1876
  • Naja tripudians var. viridis 1913
  • Naja tripudians var. sagittifera 1913

In 1940, Malcolm Arthur Smith classified the monocled cobra as a subspecies of the spectacled cobra under the trinomial Naja naja kaouthia.[5]

  • Naja kaouthia kaouthia – Deraniyagala, 1960

Characteristics[edit]

A young monocled cobra

The monocled cobra has an O-shaped, or monocellate hood pattern, unlike that of the Indian cobra. Coloration in the young is more constant. The dorsal surface may be yellow, brown, gray, or blackish, with or without ragged or clearly defined cross bands. It can be olivaceous or brownish to black above with or without a yellow or orange-colored, O-shaped mark on the hood. It has a black spot on the lower surface of the hood on either side, and one or two black cross-bars on the belly behind it. The rest of the belly is usually of the same color as the back, but paler. As age advances, it becomes paler, when the adult is brownish or olivaceous. The elongated nuchal ribs enable a cobra to expand the anterior of the neck into a “hood”. A pair of fixed anterior fangs is present. The largest fang recorded measured 6.78 mm (0.678 cm). Fangs are moderately adapted for spitting.[6] Adult monocled cobras reach a length of 1.35 to 1.5 m (4.4 to 4.9 ft) with a tail length of 23 cm (9.1 in). Many larger specimens have been recorded, but they are rare. Adults can reach a maximum of 2.3 m (7.5 ft) in length.[7][8]

Scalation[edit]

They have 25 to 31 scales on the neck, 19 to 21, usually 21, on the body, and 17 or 15 on the front of the vent. They have 164 to 197 ventral scales and 43 to 58 subcaudal scales.[7]

Monocled cobras tend to have more than one cuneate scale on each side. The shape of the frontal scale is short and square. Ventrals in males range from 170 to 192, in females from 178 to 197. Subcaudals in males range from 48 to 61, in females from 46 to 59.[6]

Distribution and habitat[edit]

Monocled cobras are distributed from India in the west through to China, Vietnam and Cambodia. They are also found on the Malay Peninsula and are native to Bangladesh, Bhutan, Myanmar, Laos, Nepal, and Thailand.

These cobras can adapt to a range of habitats, from natural to anthropogenically impacted environments. They prefer habitats associated with water, such as paddy fields, swamps, and mangroves, but can also be found in grasslands, shrublands, and forests. The species also occurs in agricultural land and human settlements, including cities. They can be found at elevations of up to 1,000 m (3,300 ft) above sea level.[1]

Ecology and behaviour[edit]

Monocled cobras are terrestrial and most active at dusk and in the evening. In rice-growing areas, they hide in rodent burrows in the dykes between fields and have become semi-aquatic in this type of habitat. Juveniles feed mostly on amphibians, and adults prey on small mammals, snakes and fish. When disturbed they prefer to take flight.[6] However, when threatened, they will raise the anterior portions of their bodies, spread their hood, usually hiss loudly, and strike in an attempt to bite and defend themselves.[8]

They are often found in tree holes and areas where rodents are plentiful.[9]

Reproduction[edit]

This is an oviparous species. Females lay between 16 and 33 eggs per clutch. Incubation periods range from 55 to 73 days.[10] Egg-laying takes place in January to March. The females usually stay with the eggs. Some collaboration between males and females has been reported in Naja naja x Naja kaouthia - hybrids.[6]

Conservation status[edit]

This species has been assessed as Least Concern by IUCN owing to its large distribution, tolerance of a broad range of habitats, including anthropogenically altered environments, and its reported abundance. No major threats have been reported, and the species is not thought to be undergoing a significant population decline. In places the distribution of this species coincides with protected areas, probably providing small safeguards. Monocled cobras are harvested for the skin trade, however, collection from the wild is minimal and not likely to be causing significant population declines.[1] Naja kaouthia is listed on CITES Appendix II.[11]

Venom[edit]

Monocled cobras at Snake Farm in Bangkok

The median lethal dose is 0.28-0.33 mg/gram of mouse body weight.[8] The major toxic components in cobra venoms are postsynaptic neurotoxins, which block the nerve transmission by binding specifically to the nicotinic acetylcholine receptor, leading to flaccid paralysis and even death by respiratory failure. The major α-neurotoxin in Naja kaouthia venom is a long neurotoxin, α-cobratoxin; the minor α-neurotoxin is different from cobrotoxin in one residue.[12] The neurotoxins of this particular species are weak.[13] The venom of this species also contains myotoxins and cardiotoxins.[14][15]

In case of intravenous injection the LD50 tested in mice is 0.373 mg/kg, and 0.225 mg/kg in case of intraperitoneal injection.[16] The average venom yield per bite is approximately 263 mg (dry weight).[17]

The monocled cobra causes the highest fatality due to snake venom poisoning in Thailand.[18] Envenomation usually presents predominantly with extensive local necrosis and systemic manifestations to a lesser degree. Drowsiness, neurological and neuromuscular symptoms will usually manifest earliest; hypotension, flushing of the face, warm skin, and pain around bite site typically manifest within one to four hours following the bite; paralysis, ventilatory failure or death could ensue rapidly, possibly as early as 60 minutes in very severe cases of envenomation. However, the presence of fang marks does not always imply that envenomation actually occurred.[19]

Extract of Mimosa pudica plant has been shown, in a preliminary study, to possibly have neutralizing effects on the toxins present in this venom. [20]

See also[edit]

References[edit]

  1. ^ a b c d Stuart, B. & Wogan, G. (2012). "Naja kaouthia". IUCN Red List of Threatened Species. Version 2014.2. International Union for Conservation of Nature. 
  2. ^ Lesson, R.-P. (1831). Catalogue des Reptiles qui font partie d’une Collection zoologique recueillie dans l’Inde continental ou en Afrique, et apportée en France par M. Lamare-Piqout. Catalogue dressé (juillet 1831). 25. Le Naja Kaouthia, Naja kaouthia, Less.. Bulletin des Sciences Naturelles et de Géologie, Tome XXV: 122.
  3. ^ Gray, J. E. (ed.) (1834). Cobra Capella. Illustrations of Indian zoology chiefly selected from the collection of Maj.-Gen. Hardwicke. Vol. II: Plate 78.
  4. ^ Cantor, T. (1839) Naja larvata. Proceedings of the Zoological Society of London. Vol. VII: 32–33.
  5. ^ Smith, M. A. (1940). Naja naja kaouthia. Records of the Indian Museum. Volume XLII: 485.
  6. ^ a b c d Wüster, W. (1998). The cobras of the genus Naja in India. Hamadryad, 23(1): 15−32.
  7. ^ a b Smith, M. A. (1943) Naja naja kaouthia In: The Fauna of British India, Ceylon and Burma, Including the Whole of the Indo-Chinese Sub-Region. Reptilia and Amphibia. Volume III (Serpentes). Taylor and Francis, London. Pages 428–432.
  8. ^ a b c Chanhome, L., Cox, M. J., Vasaruchaponga, T., Chaiyabutra, N. Sitprija, V. (2011). Characterization of venomous snakes of Thailand. Asian Biomedicine 5 (3): 311–328.
  9. ^ "Naja kaouthia: General Details and Information". WCH Clinical Toxinology Resource. University of Adelaide. Retrieved 3 February 2012. 
  10. ^ Chanhome, L, Jintkune, P., Wilde, H., Cox, M. J. (2001). Venomous snake husbandry in Thailand. Wilderness and Environmental Medicine 12: 17–23.
  11. ^ "Status of Naja kaouthia". CITES species database. CITES. Retrieved 3 February 2012. 
  12. ^ Wei, J.-F., Lü, Q.-M., Jin, Y., Li, D.-S., Xiong, Y.-L., Wang, W.-Y. (2003). α-Neurotoxins of Naja atra and Naja kaouthia Snakes in Different Regions. Acta Biochimica et Biophysica Sinica 35 (8): 683–688.
  13. ^ Ogay, A.; Rzhevskya, D. I.; Murasheva, A. N.; Tsetlinb, V. I.; Utkin, Y. N. (2005). "Weak neurotoxin from Naja kaouthia cobra venom affects haemodynamic regulation by acting on acetylcholine receptors". Toxicon 45 (1): 93–99. doi:10.1016/j.toxicon.2004.09.014. PMID 15581687. Retrieved 25 December 2011. 
  14. ^ Mahanta, M.; Mukherjee, A. K. (2001). "Neutralisation of lethality, myotoxicity and toxic enzymes of Naja kaouthia venom by Mimosa pudica root extracts". Journal of Ethnopharmacology 75 (1): 55–60. doi:10.1016/S03788741(00)003731. Retrieved 25 December 2011. 
  15. ^ Fletcher, J. E.; Jiang, M.-S.; Gong, Q.-H.; Yudkowsky, M. L.; Wieland, S. J. (1991). "Effects of a cardiotoxin from Naja naja kaouthia venom on skeletal muscle: Involvement of calcium-induced calcium release, sodium ion currents and phospholipases A2 and C". Toxicon 29 (12): 1489–1500. doi:10.1016/0041-0101(91)90005-C. PMID 1666202. Retrieved 25 December 2011. 
  16. ^ Fry, Dr. Bryan Grieg. "LD50 Menu". Australian Venom Research Unit. University of Queensland. Retrieved 25 December 2011. 
  17. ^ Engelmann, W.-E. (1981). Snakes: Biology, Behavior, and Relationship to Man. Leipzig; English version NY, USA: Leipzig Publishing; English version published by Exeter Books (1982). p. 51. ISBN 0-89673-110-3. 
  18. ^ Pratanaphon, R.; Akesowan, S.; Khow, O.; Sriprapat, S.; Ratanabanangkoon, K. (1997). "Production of highly potent horse antivenom against the Thai cobra (Naja kaouthia)". Vaccine 15 (14): 1523–1528. doi:10.1016/S0264-410X(97)00098-4. PMID 9330463. Retrieved 25 December 2011. 
  19. ^ Davidson, T. "Snakebite Protocols: Summary for Human Bite by Monocellate Cobra (Naja naja kaouthia)". 
  20. ^ http://www.sciencedirect.com/science/article/pii/S0378874100003731

Further reading[edit]

  • Wüster, Wolfgang (1993). A century of confusion: Asiatic cobras revisited. Vivarium 4 (4): 14–18
  • Cox, Merel J. (1995). Naja kaouthia Herpetological Review 26 (3): 156–157
  • Kyi, S. W., Zug, G. R. (2003). Unusual foraging behaviour of Naja kaouthia at the Moyingye Wetlands Bird Sanctuary, Myanmar. Hamadryad 27 (2): 265–266
  • Wüster, W. Thorpe, R.S. (1991). Asiatic cobras: Systematics and snakebite. Experientia 47: 205–209
  • Wüster, W., Thorpe, R.S., Cox, M.J., Jintakune, P., Nabhitabhata, J. (1995). "Population systematics of the snake genus Naja (Reptilia: Serpentes: Elapidae) in Indochina: Multivariate morphometrics and comparative mitochondrial DNA sequencing (cytochrome oxidase I)". Journal of Evolutionary Biolology 8: 493–510
  • Wüster, W. (1996). Taxonomic changes and toxinology: Systematic revisions of the Asiatic cobras (Naja naja complex). Toxicon 34 (4): 399–406
  • Wüster, W. (1998). The cobras of the genus Naja in India Hamadryad 23 (1): 15–32
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