The monocled cobra (''Naja kaouthia''), also called monocellate cobra and Indian spitting cobra, is a venomous
cobra species widespread across
South
South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...
and
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...
and listed as
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
on the
IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
.
[
]
Taxonomy
The scientific name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
''Naja kaouthia'' was proposed by René Lesson
René-Primevère Lesson (20 March 1794 – 28 April 1849) was a French surgeon, naturalist, ornithologist, and herpetologist.
Biography
Lesson was born at Rochefort, and entered the Naval Medical School in Rochefort at the age of sixteen. He ...
in 1831, when he described the monocled cobra as a beautiful snake that is distinct from the spectacled cobra
The Indian cobra (''Naja naja''), also known as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of cobra found in India, Pakistan, Bangladesh, Sri Lanka, Nepal, and Bhutan, and a member of the "big four" species that are ...
, with 188 ventral scales and 53 pairs of caudal scales.
Since then, several monocled cobras were described under different scientific name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
s:
* In 1834, John Edward Gray
John Edward Gray, FRS (12 February 1800 – 7 March 1875) was a British zoologist. He was the elder brother of zoologist George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray (1766–1828). The same is used for ...
published Thomas Hardwicke
Major-General Thomas Hardwicke (1756 – 3 March 1835) was an English soldier and naturalist who was in India from 1777 to 1823. He collected numerous specimens of natural history and had them painted by Indian artists. From these paintings ma ...
's first illustration of a monocled cobra under the trinomial
In elementary algebra, a trinomial is a polynomial consisting of three terms or monomials.
Examples of trinomial expressions
# 3x + 5y + 8z with x, y, z variables
# 3t + 9s^2 + 3y^3 with t, s, y variables
# 3ts + 9t + 5s with t, s variables
# a ...
''Naja tripudians'' var. ''fasciata''.
* In 1839, Theodore Edward Cantor
Theodore Edward (Theodor Edvard) Cantor (1809–1860) was a Danish physician, zoologist and botanist.
Born to a Danish Jewish family, his mother was a sister of Nathaniel Wallich. Cantor worked for the British East India Company, and made natur ...
described a brownish monocled cobra with numerous faint yellow transverse stripes and a hood marked with a white ring under the binomial
Binomial may refer to:
In mathematics
*Binomial (polynomial), a polynomial with two terms
* Binomial coefficient, numbers appearing in the expansions of powers of binomials
*Binomial QMF, a perfect-reconstruction orthogonal wavelet decomposition
...
''Naja larvata'', found in Bombay
Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second- ...
, Calcutta
Kolkata (, or , ; also known as Calcutta , List of renamed places in India#West Bengal, the official name until 2001) is the Capital city, capital of the Indian States and union territories of India, state of West Bengal, on the eastern ba ...
, and Assam
Assam (; ) is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of . The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur ...
.
Several varieties of monocled cobras were described under the binomial ''Naja tripudians'' between 1895 and 1913:
*''N. j.'' var. ''scopinucha'' 1895
*''N. j.'' var. ''unicolor'' 1876
*''N. j.'' var. ''viridis'' 1913
*''N. j.'' var. ''sagittifera'' 1913
In 1940, Malcolm Arthur Smith
Malcolm Arthur Smith (1875 in New Malden, Surrey – 1958 in Ascot) was a herpetologist and physician working in the Malay Peninsula.
Early life
Smith was interested in reptiles and amphibians from an early age. After completing a degree in med ...
classified the monocled cobra as a subspecies of the spectacled cobra under the trinomial ''Naja naja kaouthia''. Reclassification in the 1990s further distinguished ''Naja kaouthia'' from ''Naja siamensis
The Indochinese spitting cobra (''Naja siamensis'') ( th, งูเห่า, pronounced: nguu hao) also called the Thai spitting cobra, Siamese spitting cobra, is a species of spitting cobra found in Southeast Asia.
Description
This is a medium ...
'', a name commonly used in older toxinological research.
Phylogenetic
In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
studies of ''Naja kaouthia'' in Thailand have demonstrated surprising variation, with one population resulting in the species becoming paraphyletic with other Asiatic cobras.
Characteristics
The monocled cobra has an O-shaped, or monocellate hood pattern, unlike that of the Indian cobra
The Indian cobra (''Naja naja''), also known as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of cobra found in India, Pakistan, Bangladesh, Sri Lanka, Nepal, and Bhutan, and a member of the "big four" species that are ...
, which has the "spectacle" pattern (two circular ocelli connected by a curved line) on the rear of its hood. The elongated nuchal ribs enable a cobra to expand the anterior of the neck into a “hood”. Coloration in the young is more constant. The dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
* Dorsal co ...
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 the same color as the back, but paler. As age advances, the snake becomes paler, wherein the adult is brownish or olivaceous. A pair of fixed anterior fangs is present. The largest fang
A fang is a long, pointed tooth. In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). Spiders also have external fang ...
recorded measured . Fangs are moderately adapted for spitting.
Adult monocled cobras reach a length of with a tail length of . Many larger specimens have been recorded, but they are rare. Adults can reach a maximum of in length.
Scalation
The monocled cobra has 25 to 31 scales
Scale or scales may refer to:
Mathematics
* Scale (descriptive set theory), an object defined on a set of points
* Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original
* Scale factor, a number w ...
on the neck, 19 to 21 on the body, and 17 or 15 on the front of the vent. It has 164 to 197 ventral scales
In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down the underside of the body from the neck to the anal scale. When counting them, the first is the anteriormost ventral scale that conta ...
and 43 to 58 subcaudal scales
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail.Wright AH, Wright AA. 1957. Handbook of Snakes. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . These scales may be either single or divided (pair ...
.[
It typically has 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.]
Distribution and habitat
The monocled cobra is distributed from India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
in the west through to China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...
and Cambodia
Cambodia (; also Kampuchea ; km, កម្ពុជា, UNGEGN: ), officially the Kingdom of Cambodia, is a country located in the southern portion of the Indochinese Peninsula in Southeast Asia, spanning an area of , bordered by Thailand t ...
. It also occurs on the Malay Peninsula
The Malay Peninsula (Malay: ''Semenanjung Tanah Melayu'') is a peninsula in Mainland Southeast Asia. The landmass runs approximately north–south, and at its terminus, it is the southernmost point of the Asian continental mainland. The area ...
and is native to West Bengal
West Bengal (, Bengali: ''Poshchim Bongo'', , abbr. WB) is a state in the eastern portion of India. It is situated along the Bay of Bengal, along with a population of over 91 million inhabitants within an area of . West Bengal is the fourt ...
, Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, Bhutan
Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...
, Myanmar
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...
, Laos
Laos (, ''Lāo'' )), officially the Lao People's Democratic Republic ( Lao: ສາທາລະນະລັດ ປະຊາທິປະໄຕ ປະຊາຊົນລາວ, French: République démocratique populaire lao), is a socialist ...
, Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
, and Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...
. It can adapt to a range of habitats, from natural to anthropogenically impacted environments. It prefer habitats associated with water, such as paddy field
A paddy field is a flooded field (agriculture), field of arable land used for growing Aquatic plant, semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in sout ...
s, swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s and mangrove
A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...
s, but lives also in grasslands, shrublands, forests, agricultural land at elevations of up to and human settlements including cities.[
]
Ecology and behaviour
Monocled cobras are terrestrial and most active at dusk. In rice-growing areas, they hide in rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...
burrows in the dykes between fields and have become semi-aquatic in this type of habitat. Juveniles feed mostly on amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
s whereas adults prey on small mammal
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s, snakes and fish. When disturbed they prefer to escape. However, when threatened they will raise the anterior portions of their bodies, spread their hood, usually hiss loudly, and strike in attempt to bite and defend themselves.
They are often found in tree holes and areas where rodents are plentiful.
Some populations of the monocled cobra have the ability to spit venom, earning them the name "Indian spitting cobra".
Reproduction
This is an oviparous
Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...
species. Females lay 16 to 33 egg
An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s per clutch
A clutch is a mechanical device that engages and disengages power transmission, especially from a drive shaft to a driven shaft. In the simplest application, clutches connect and disconnect two rotating shafts (drive shafts or line shafts). ...
. Incubation periods range from 55 to 73 days. Egg-laying takes place January through March. The females usually stay with the eggs. Some collaboration between males and females has been reported in ''Naja naja'' x ''Naja kaouthia'' - hybrid
Hybrid may refer to:
Science
* Hybrid (biology), an offspring resulting from cross-breeding
** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species
** Hybridity, the property of a hybrid plant which is a union of two dif ...
s.
Conservation status
The monocled cobra is listed on CITES Appendix II
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
and has been assessed as Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...
on the IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...
due 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 it is not thought to be undergoing a significant population decline. Monocled cobras are harvested for the wildlife trade
Wildlife trade refers to the of products that are derived from non-domesticated animals or plants usually extracted from their natural environment or raised under controlled conditions. It can involve the trade of living or dead individuals, ti ...
, however, collection from the wild is minimal and not likely to cause significant population declines.[
]
Venom
The venom of the monocled cobra from three different localities were reported to exhibit different intravenous and subcutaneous median lethal dose
In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ...
: Thailand, 0.18-0.22 µg/g; Malaysia, 0.90-1.11 µg/g; and Vietnam, 0.90-1.00 µg/g, of mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
body weight. These results reflect the distinct difference in the lethal potency of the monocled cobra and response to antivenom neutralization.
The major toxic components in cobra venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
s are postsynaptic neurotoxin
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature ner ...
s, which block the nerve transmission by binding specifically to the nicotinic
Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ner ...
acetylcholine receptor
An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.
Classification
Like other transmembrane receptors, acetylcholine receptors are classified according ...
, leading to flaccid paralysis
Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...
and even death by respiratory failure. The major α-neurotoxin in the monocled cobra's venom is a long neurotoxin, α-cobratoxin
α-Cobratoxin is a substance of the venom of certain ''Naja'' cobras. It is a nicotinic acetylcholine receptor (nAChR) antagonist which causes paralysis by preventing the binding of acetylcholine to the nAChR.
Sources
α-Cobratoxin is a neurot ...
; the minor α-neurotoxin is different from cobrotoxin in one residue
Residue may refer to:
Chemistry and biology
* An amino acid, within a peptide chain
* Crop residue, materials left after agricultural processes
* Pesticide residue, refers to the pesticides that may remain on or in food after they are applied ...
. The neurotoxins of this particular species are weak. The venom of this species also contains myotoxin
Myotoxins are small, basic peptides found in snake venoms (e.g. rattlesnakes) and lizard venoms (e.g. Mexican beaded lizard). This involves a non-enzymatic mechanism that leads to severe muscle necrosis. These peptides act very quickly, causing i ...
s and cardiotoxin
Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. The heart becomes weaker and is not as efficient in pumping blood. Cardiotoxicity may be caused by chemotherapy (a usual example is th ...
s.
In case of intravenous injection
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutri ...
the tested in mice is 0.373 mg/kg, and 0.225 mg/kg in case of intraperitoneal injection
Intraperitoneal injection or IP injection is the injection of a substance into the peritoneum (body cavity). It is more often applied to animals than to humans. In general, it is preferred when large amounts of blood replacement fluids are needed ...
. The average venom yield per bite is approximately 263 mg dry weight.
The monocled cobra causes the highest fatality due to snake venom poisoning in Thailand. Envenomation
Envenomation is the process by which venom is injected by the bite or sting of a venomous animal.
Many kinds of animals, including mammals (e.g., the northern short-tailed shrew, ''Blarina brevicauda''), reptiles (e.g., the king cobra), spider ...
usually presents predominantly with extensive local necrosis
Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...
and systemic manifestations to a lesser degree. Drowsiness, neurological and neuromuscular symptoms will usually manifest earliest; hypotension
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dias ...
, flushing of the face, warm skin, and pain around bite site typically manifest within one to four hours following the bite; paralysis
Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...
, 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.
See also
* Snakebite
A snakebite is an injury caused by the bite of a snake, especially a venomous snake. A common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. Sometimes venom injection from the bite may occu ...
References
Further reading
*
*
*
*
* Wüster, W. Thorpe, R.S. (1991). ''Asiatic cobras: Systematics and snakebite.'' Experientia 47: 205–209
*
*
External links
*
The Asiatic Cobra Systematics Page
Clinical Toxinology Resources : ''Naja kaouthia''
Thailand Snakes : ''Naja kaouthia''
{{Taxonbar, from=Q41165
Fauna of Southeast Asia
Naja
Reptiles described in 1831
Reptiles of Bangladesh
Reptiles of Bhutan
Reptiles of Cambodia
Reptiles of Laos
Reptiles of Nepal
Snakes of China
Snakes of India
Snakes of Myanmar
Snakes of Thailand
Snakes of Vietnam
Taxa named by René Lesson