The
king cobra is the world's longest venomous
snakeSnakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
, with a length up to 5.6 m (18.5 ft). This species, which preys chiefly on other snakes, is found predominantly in forests from
IndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
through
Southeast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
to the
PhilippinesThe Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
and
IndonesiaIndonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
. Despite the word "cobra" in its name, this snake is not a member of
NajaNaja is a genus of venomous elapid snakes. Although there are several other genera that share the common name, Naja are the most recognized and most widespread group of snakes commonly known as cobras. The genus Naja consists of 20 to 22 species, but has undergone several taxonomic revisions in...
("true cobras") but belongs to its own
genusIn biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
.
Profile
The king cobra is a large and powerful snake, averaging 3 metre in length and typically weighing about 6 kilograms (13.2 lb). The longest known specimen was kept captive at the
London ZooLondon Zoo is the world's oldest scientific zoo. It was opened in London on 27 April 1828, and was originally intended to be used as a collection for scientific study. It was eventually opened to the public in 1847...
, and grew to around 18.5 foot before being
euthanizedEuthanasia refers to the practice of intentionally ending a life in order to relieve pain and suffering....
upon the outbreak of
World War IIWorld War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The heaviest wild specimen was caught at Royal Island Club in
SingaporeSingapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
in 1951 which weighed 12 kilograms (26.5 lb) and measured 4.8 metres (15.7 ft), though an even heavier captive specimen was kept at
New York Zoological ParkThe Bronx Zoo is located in the Bronx borough of New York City, within Bronx Park. It is the largest metropolitan zoo in the United States, comprising of park lands and naturalistic habitats, through which the Bronx River flows....
and was measured as 12.7 kilograms (28 lb) at 4.4 metres (14.4 ft) long in 1972. Recently a 12ft king Cobra was found in Tripura(India). The length and mass of the snakes highly depend on their localities and some other factors. Despite their large size, typical king cobras are fast and agile.
Characteristics
The
skin-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
of this snake is either olive-green, tan, or black, and it has faint, pale yellow cross bands down the length of the body. The belly is cream or pale yellow, and the scales are smooth. Juveniles are shiny black with narrow yellow bands (can be mistaken for a banded krait, but readily identified with its expanded hood). The head of a mature snake can be quite massive and bulky in appearance, though like all snakes, they can expand their jaws to swallow large prey items. It has proteroglyph dentition, meaning it has two short, fixed fangs in the front of the mouth which channel venom into the prey like hypodermic needles. The male is larger and thicker than the female. The average lifespan of a wild king cobra is about 20 years.
Identification
The king cobra is the sole member of genus
Ophiophagus, while most other cobras are members of the genus
Naja. They can be distinguished from other cobras by size and hood marks. King cobras are generally larger than other cobras, and the stripe on the neck is like the symbol "^" instead of a double or single eye(s) shape that may be seen in most of the other Asian cobras. A foolproof method of identification is if on the head, clearly visible, is the presence of a pair of large scales known as occipitals, at the back of the top of the head. These are behind the usual "nine-plate" arrangement typical of colubrids and elapids, and are unique to the king cobra.
Scalation
Dorsal scales: midbody 15 rows; Ventral scales: Males 235-250, females 239-265; Tail: Subcaudal scales single or paired in each row, 83-96 in males and 77-98 in females.
Habitat
The king cobra is distributed across South Asia, Southeast Asia, and the southern areas of East Asia (southern
ChinaChinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
) where it is not common. It lives in dense highland forests, preferring areas dotted with lakes and streams. King cobra populations have dropped in some areas of its range because of the
destruction of forestsDeforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use....
. It is listed as an Appendix II Animal within CITES.
Behaviour
King cobras, like other snakes, receive chemical information ("smell") via their
forked tongueA forked tongue is a tongue split into two distinct tines at the tip; this is a feature common to many species of reptiles. Reptiles smell using the tip of their tongue, and a forked tongue allows them to sense from which direction a smell is coming. Sensing from both sides of the head and...
s, which pick up scent particles and transfer them to a special sensory receptor (
Jacobson's organThe vomeronasal organ , or Jacobson's organ, is an auxiliary olfactory sense organ that is found in many animals. It was discovered by Frederik Ruysch and later by Ludwig Jacobson in 1813....
) located in the roof of its mouth. When the scent of a meal is detected, the snake flicks its tongue to gauge the prey's location (the twin forks of the tongue acting in stereo); it also uses its keen eyesight (king cobras are able to detect moving prey almost 100 m [300 feet] away), intelligence and sensitivity to earth-borne
vibrationVibration refers to mechanical oscillations about an equilibrium point. The oscillations may be periodic such as the motion of a pendulum or random such as the movement of a tire on a gravel road.Vibration is occasionally "desirable"...
to track its prey.
Another theory, not yet proven beyond doubt, is that the king cobra has a very sharp memory. According to a myth, the picture of the killer of a king cobra stays in the eyes of the snake, which is later picked up by the partner and is used to hunt down the killer for revenge. To prove this theory, a king cobra was captured and left free in an enclosure which had small openings. Numerous people stood in front of the openings but the snake rose to its full height and locked eyes only with the captor. Due to this myth, whenever a cobra is killed, specially in India, the head is either crushed or burned in order to damage the eyes completely. Following envenomation, the king cobra will begin to swallow its struggling prey while its toxins begin the
digestionDigestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....
of its victim. King cobras, like all snakes, have flexible jaws. The jaw bones are connected by pliable ligaments, enabling the lower jaw bones to move independently, enabling the King cobra to swallow its prey whole. The expansion of the jaw enables the snake to swallow prey much larger than its head.
King cobras are able to hunt at all times of day, although it is rarely seen at night, leading most herpetologists to classify it as a
diurnalDiurnality is a plant or animal behavior characterized by activity during the day and sleeping at night.-In animals:Animals that are not diurnal might be nocturnal or crepuscular . Many animal species are diurnal, including many mammals, insects, reptiles and birds...
species.
Defense
When confronted this species will quickly attempt to escape and avoid any sort of confrontation. However, if cornered, the king cobra can be very aggressive if provoked. When threatened, it rears up the anterior portion of its body when extending the neck, showing the
fangFang is a mammal's canine tooth.Fang may also refer to:* A snake's poison-injecting tooth: see snake venom* Fang people, in Central Africa* Fang language, spoken by Fang people...
s and hissing loudly. It can be easily irritated by closely approaching objects or sudden movements. When raising its body, the king cobra can still move forward to strike and the attack range can be as far as 2 meters; it is possible for people to easily misjudge the safe zone. The king cobra may deliver multiple bites in a single attack but adults are known to bite and hold on. In spite of being a highly dangerous snake, it prefers to escape first unless there is no way to go.
Since this species is secretive and tends to inhabit less-populated forested regions and dense jungle, it is rarely encountered.
If a king cobra encounters a natural predator, such as the
mongooseMongoose are a family of 33 living species of small carnivorans from southern Eurasia and mainland Africa. Four additional species from Madagascar in the subfamily Galidiinae, which were previously classified in this family, are also referred to as "mongooses" or "mongoose-like"...
, which has resistance to the neurotoxins, the snake generally tries to flee. If unable to do so, it forms the distinctive cobra hood and emits a hiss, sometimes with feigned closed-mouth strikes. These efforts usually prove to be very effective, especially since it is more dangerous than other mongoose prey, as well as being much too large for the small mammal to kill with ease.
Diet
The king cobra's genus name,
Ophiophagus is a
GreekGreek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
derived word which means "snake-eater", and its diet consists primarily of other snakes, including ratsnakes, small pythons and even other venomous snakes such as various members of the true cobras (of the genus
Naja), and even the much more venomous members of the krait family. When food is scarce, they may also feed on other small vertebrates, such as lizards, birds, and rodents. In some cases, the cobra may "constrict" its prey, such as birds and larger rodents, using its muscular body, though this is uncommon. After a large meal, the snake may live for many months without another one because of its slow
metabolic rateMetabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
. The king cobra's most common meal is the ratsnake; pursuit of this species often brings king cobras close to human settlements.
Venom
The
venomVenom is the general term referring to any variety of toxins used by certain types of animals that inject it into their victims by the means of a bite or a sting...
of the king cobra consists primarily of
neurotoxinA neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
s, but it also contains cardiotoxic and some other compounds. Toxic constituents are mainly proteins and polypeptides.
During a bite, venom is forced through the snake's 1.25 centimetre fangs into the wound, and the toxins begin to attack the victim's
central nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
. Symptoms may include severe pain, blurred vision,
vertigoVertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...
, drowsiness, and
paralysisParalysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
. Envenomation progresses to cardiovascular collapse, and the victim falls into a
comaIn medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
. Death soon follows due to
respiratory failureThe term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
. Moreover, king cobra envenomation is clinically known to cause
renal failureRenal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
.
A 1990 book makes a passing statement of a of 0.34 mg/kg for this species, however this value is inconsistent with most toxicological studies. For example, a recent study lists the of the king cobra venom as 1.6 mg/kg – 1.8 mg/kg, making it's venom one of the least potent among the elapids. This value is further backed up by another toxicological study which lists the of the king cobra at 1.7 mg/kg. A similar mean value of 1.93 mg/kg was obtained from the venom of five wild caught king cobras in
Southeast AsiaSoutheast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
(Meier et al 1995).
This species is capable of delivering a large quantity of venom, injecting a dose anywhere from 200-500 milligrams on average and can up to 7ml. Though the venom is weak compared to most other elapids based upon the
LD50In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after a specified test duration...
in mice, it can still deliver a bite which can potentially kill a human due to the massive amount of venom it delivers in a single bite. Mortality can vary sharply with amount of venom involved, most bites involve nonfatal amounts. According to a research report from the
University of AdelaideThe University of Adelaide is a public university located in Adelaide, South Australia. Established in 1874, it is the third oldest university in Australia...
Department of Toxinology, an untreated bite has a mortality rate of 50-60% Depending on many factors, especially in cases of very severe envenomation, death can occur as early as 30
minuteA minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
s after being bitten by this species but this is exceptionally rare as most untreated bite victims in Asia live through their bites, usually because the vast majority of bites involve non-fatal amounts of venom.
There are two types of antivenom made specifically to treat king cobra envenomations. The
Red CrossThe International Red Cross and Red Crescent Movement is an international humanitarian movement with approximately 97 million volunteers, members and staff worldwide which was founded to protect human life and health, to ensure respect for all human beings, and to prevent and alleviate human...
in Thailand manufactures one, and the Central Research Institute in India manufactures the other; however, both are made in small quantities and are not widely available. Ohanin, a protein component of the venom, causes hypolocomotion and hyperalgesia in mammals. Other components have cardiotoxic, cytotoxic and neurotoxic effects. In Thailand, a concoction of
alcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
and the ground
rootIn vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
of
turmericTurmeric is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae. It is native to tropical South Asia and needs temperatures between 20 °C and 30 °C and a considerable amount of annual rainfall to thrive...
is ingested, which has been clinically shown to create a strong resilience against the venom of the king cobra, and other snakes with neurotoxic venom.
The haditoxin in the king cobra venom was discovered by Singaporean scientists to be structurally unique and can have unique pharmacological properties. Biochemical studies confirmed that it existed as a non-covalent dimer species in solution. Its structural similarity to short-chain α-neurotoxins and κ-neurotoxins notwithstanding, haditoxin exhibited unique blockade of α7-nAChRs (IC50 180 nM), which is recognized by neither short-chain α-neurotoxins nor κ-neurotoxins.
Reproduction
The king cobra is unusual among snakes in that the female king cobra is a very dedicated parent. She makes a nest for her eggs, scraping up leaves and other debris into a mound in which to deposit them, and remains in the nest until the young hatch.
A female usually deposits 20 to 40 eggs into the mound, which acts as an incubator. She stays with the eggs and guards the mound tenaciously, rearing up into a threat display if any large animal gets too close, for roughly 60 to 90 days.
Inside the mound the eggs are incubated at a steady 28 °C (82 °F). When the eggs start to hatch, instinct causes the female to leave the nest and find prey to eat so she does not eat her young. The baby king cobras, with an average length of 45 centimetre, have venom which is as potent as that of the adults. They may be brightly marked but these colours often fade as they mature. They are alert and nervous, being highly aggressive if disturbed.
Other culture
In
BurmaBurma , officially the Republic of the Union of Myanmar , is a country in Southeast Asia. Burma is bordered by China on the northeast, Laos on the east, Thailand on the southeast, Bangladesh on the west, India on the northwest, the Bay of Bengal to the southwest, and the Andaman Sea on the south....
, king cobras are often used by female
snake charmerSnake charmer can mean:*Snake charming, the practice of "hypnotizing" snakes*Snake Charmer, a 1983 album by guitarist The Edge, bassist Jah Wobble, multi-instrumentalist Holger Czukay, drummer Jaki Liebezeit, and DJ/remixer François Kevorkian...
s. The charmer is usually tattooed with three pictograms, using an ink mixed with snake venom; superstition holds that it protects the charmer from the snake. The charmer kisses the snake on the top of its head at the end of the show.
Hiss
Bioacoustic analysisBioacoustics is a cross-disciplinary science that combines biology and acoustics. Usually it refers to the investigation of sound production, dispersion through elastic media, and reception in animals, including humans. This involves neurophysiological and anatomical basis of sound production and...
of the "growl" of the king cobra has shown that it differs significantly from other snakes. Generally a typical snake hiss has a broad-frequency span [~3,000 to 13,000
HzThe hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
] with a dominant frequency near 7,500 Hz, whereas the "growl" of the king cobra consists of frequencies below 2,500 Hz, with a dominant frequency near 600 Hz.
Related species
The king cobra belongs to the family
ElapidaeElapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
which includes other well known snakes, such as the various species of
cobraCobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...
(ie.
Cape cobraThe Cape Cobra or yellow cobra is a moderately sized, highly venomous cobra inhabiting a wide variety of biomes across Southern Africa...
,
Indian cobraIndian Cobra 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. This snake is revered in Indian mythology and culture, and is often seen with snake charmers...
, etc), the
coral snakeThe coral snakes are a large group of elapid snakes that can be subdivided into two distinct groups, Old World coral snakes and New World coral snakes...
, the
death adderAcanthophis is a genus of elapid snakes. Commonly called death adders, they are native to Australia, New Guinea and nearby islands, and are among the most venomous snakes in the world...
, kraits,
mambaMambas, of the genus Dendroaspis , are a group of highly venomous, fast-moving land-dwelling snakes of Africa. They belong to the family of Elapidae which includes cobras, coral snakes, taipans, brown snakes, tiger snakes, death adders, kraits and, debatably, sea snakes...
s, and
taipanThe taipans are a genus of large, fast, highly venomous Australasian snakes of the elapid family.-Overview:The taipan was named by Donald Thomson after the word used by the Wik-Mungkan Aboriginal people of central Cape York Peninsula, Queensland, Australia.There are three known species: the coastal...
s.