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King cobra

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This article is about the snake. For King Cobra (disambiguation), see King cobra (disambiguation).

King Cobra
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Reptilia
Order:
Squamata
Suborder:
Serpentes
Family:
Elapidae
Genus:
Ophiophagus
Species:
O. hannah
Binomial name
Ophiophagus hannah
Cantor, 1836
  Distribution of the King Cobra

The King Cobra (Ophiophagus hannah) is the world's longest venomous snake, with a length up to 5.6 m (18.5 ft).[1] This species is widespread throughout Southeast Asia and parts of India, and is found mostly in forested areas. King Cobra is fierce, agile and can produce large amount of potent venom in a single bite. It is one of the most dangerous and feared Asiatic snakes. [2]

Profile

The King Cobra is a large and powerful snake, averaging 3.6–4 m (12–13 feet) in length and typically weighing about 6 kg (13.2 lb). A particularly large specimen was kept captive at the London Zoo and grew to 5.7 m (18.8 ft) before being euthanized upon the outbreak of World War II.[3] Despite their large size, King Cobras are fast and agile.

Characteristics

The skin 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 King Cobra is about 20 years.

Identification

Actually the King cobra is not a kind of cobra at all; it belongs to its own genus instead of the Naja genus. It can be identified from other cobras by its size and the pattern on its neck. King cobras are larger than other cobras, and the stripe on its neck is like the symbol "^" instead of a double or single eye(s) shape that may be seen in other cobras.

Habitat

The King Cobra is distributed across South and South-east Asia, but is not common. It lives in dense highland forests,[1][4], preferring areas dotted with lakes and streams. King Cobra populations have dropped in some areas of its range because of the destruction of forests, but despite this the snake is not listed by the IUCN as in danger of becoming extinct. It is, however, listed as an Appendix II Animal within CITES.[5]

Scalation of the King Cobra

Behavior

King Cobras, like other snakes, receive chemical information (“smell”) via their forked tongues, which pick up scent particles and transfer them to a special sensory receptor (Jacobson's Organ) located in the roof of its mouth.[1] When the scent of a meal has been detected, the snake will flick its tongue to gauge the prey's direction (the twin forks of the tongue acting in stereo); it will also rely on its keen eyesight (King Cobras are able to detect moving prey almost 100 m [300 feet] away), intelligence[6] and sensitivity to earth-borne vibration to track its prey.[7] Following envenomation, the King Cobra will begin to swallow its struggling prey while its toxins begin the digestion of its victim.[1] King Cobras, as with all other snakes, do not have rigidly fixed jaws. Instead, the jaw bones are connected by extremely pliable ligaments, enabling the lower jaw bones to move independently of each other.[1] Like other snakes, the King Cobra does not chew its food, instead it swallows its prey whole. The expansion of the jaw enables the snake to swallow prey much larger than its head.[1]

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 diurnal species.[1][8]

When threatened, King Cobras raise up one-third of their body, flattening the neck (which can be the girth of an adult's forearm), showing the fangs and hissing loudly. They are easily irritated by closely approaching objects or sudden movements. King cobras attack quickly and the strike distance can be as far as 7 feet, people can easily misjudge the safe distance. King Cobras can deliver more than one bite in a single attack when feeling concern. Also, they will have a strong hold when they do bite.[9]

If a King Cobra encounters a natural predator, such as the mongoose, which has some resistance to the neurotoxins,[10] the snake generally tries to flee. If unable to do so, it forms the distinctive cobra hood and emits a high-pitched hiss, sometimes with feigned closed-mouth strikes. These efforts usually prove to be very effective, especially since the King Cobra is more dangerous than other mongoose prey as well as being much too large for the small mammal to kill with ease.

Diet

King cobra's genus name, Ophiophagus, literally means "snake-eater", and its diet consists primarily of other snakes, including rat snakes, sizeable pythons and even other venomous snakes (including kraits, cobras and smaller members of its own species)[8][11]. When food is scarce, King Cobras may also feed on other small vertebrates such as lizards, birds, and rodents. In some cases, the cobra may “constrict” its prey, like birds and larger rodents using its muscular body, though this is uncommon.[1][11] After a large meal the snake may live for many months without another one because of its slow metabolic rate.[1] The King Cobra's most common meal is the Ratsnake. This leads King Cobras near human settlements. On rare occasions the king cobra has been known to eat humans. This is especially significant as human settlement encroches on their native lands.

Venom

The venom of King Cobra is primarily neurotoxic but also contains cardiotoxic[8]. It is composed mostly of proteins and polypeptides. When biting, venom is forced through the snake's half-inch (1.25 cm) fangs and into the wound. It will soon attack the victim's central nervous system and induces severe pain, blurred vision, vertigo, drowsiness, and paralysis.[12] Envenomation progresses to cardiovascular collapse, and the victim falls into a coma. Death soon follows because of respiratory failure. In the past, the LD50 of King Cobra’s venom was treated as 1.7 mg/kg (which is one of the least toxic elapids.) However, this is not always true. According to the recent toxinology study, the LD50 of Chinese King Cobra venom is 0.34 mg/kg [13]. This shows that actually King Cobra can be more venomous than most of the other species with its range, like chinese cobra[14]. A part from this, King Cobra is also capable of delivering larger quantities of venom than most other venomous snakes. It injects 380-600 mg of venom in a single bite. This is enough to kill 20-40 grown men or even an elephant. One bite from a King Cobra can cause death within 15 minutes for a human[13]. However, death usually occurs between 30–45 minutes[14][12][15].The mortality rate from a bite can be over 75%[8][16], or only 33%, depending upon treatment details. It is regarded as one of the deadliest snakes in the world.[14]

There are two types of antivenom made specifically to treat King Cobra envenomations. The Red Cross 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.[17] Ohanin, a protein component of the venom, causes hypolocomotion and hyperalgesia in mammals.[18] Other components have cardiotoxic,[19] cytotoxic and neurotoxic effects.[20]

Reproduction

The female King Cobra is a very dedicated parent. Before she is ready to lay her eggs, she uses the coils of her long body to gather a big mound of leaf litter. She deposits 20–40 eggs into the mound, which acts as an incubator. The female stays with her eggs and guards the mound tenaciously, rearing up into a threat display if any large animal gets too close.[21]

Inside the mound that the female has built the eggs are incubated at a steady 28 °C (82 °F). When the eggs start to hatch, instinct causes her to leave the nest and find prey to eat so that she does not eat her young.[22] The baby King Cobras can have a length of 55 cm (22 in), and have already developed potent venom which is as deadly as that of an adult.

Other culture

In Burma, King Cobras are often used by female snake charmers.[11] 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.[11] The charmer kisses the snake on the top of its head at the end of the show.[11]

The King Cobra belongs to the family Elapidae. There are over 200 species of elapid found around the world, except Antarctica and Europe. All are venomous and have short, fixed fangs (proteroglyphs), but may differ widely in habits, behaviour and appearance. Four better known species of the Elapidae are the Coral Snake, Death Adder, Black mamba, and of course, the King Cobra.

  • King Cobra in St. Louis Zoo
    King Cobra in St. Louis Zoo
  • King Cobra found in forest
    King Cobra found in forest
  • South Indian King Cobra
    South Indian King Cobra
  • Adult male King Cobra
    Adult male King Cobra
Wikimedia Commons has media related to Ophiophagus hannah.

References

  1. ^ a b c d e f g h i Mehrtens, John (1987). Living Snakes of the World. New York: Sterling. ISBN 0806964618.
  2. ^ A Fleld Guide to the Venomous Land Snakes of Hong Kong. Hong Kong: Cosmos Books Ltd. ISBN 9882113265.
  3. ^ Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0851122359
  4. ^ Miller, Harry (September 1970), "The Cobra, India's 'Good Snake'", National Geographic, 20: 393–409{{citation}}: CS1 maint: date and year (link)
  5. ^ "CITES List of animal species used in traditional medicine". Retrieved 2007-09-01.
  6. ^ Philadelphia Zoo - King cobra
  7. ^ Taylor, David (1997), King Cobra., retrieved 2007-09-08
  8. ^ a b c d Capula, Massimo (1989). Simon & Schuster's Guide to Reptiles and Amphibians of the World. New York: Simon & Schuster. ISBN 0671690981. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  9. ^ "King Cobra".
  10. ^ Dr. Zoltan Takacs. "Why the cobra is resistant to its own venom". Retrieved 2007-09-05.
  11. ^ a b c d e Coborn, John (October 1991). The Atlas of Snakes of the World. New Jersey: TFH Publications. pp. 30, 452. ISBN 978-0866227490.
  12. ^ a b Freiberg, Dr. Marcos (1984). The World of Venomous Animals. New Jersey: TFH. ISBN 0876665679. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  13. ^ a b Snake of medical importance. Venom and research group.
  14. ^ a b c Tun-Pe, Tun-Pe, Warrell DA, Tin-Myint (1995). "King cobra (Ophiophagus hannah) bites in Myanmar: venom antigen levels and development of venom antibodies". Toxicon. 33 (3): 379–82. PMID 7638877. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  15. ^ "MSN Encarta: King Cobra". MSN Encarta. Archived from the original on 2009-10-31. Retrieved 2007-09-05. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  16. ^ "Ophitoxaemia (venomous snake bite)". Retrieved 2007-09-05.
  17. ^ "Munich AntiVenom Index:Ophiophagus hannah". Munich Poison Center. MAVIN (Munich AntiVenom Index). 01/02/2007. Retrieved 2007-09-02. {{cite web}}: Check date values in: |date= (help)
  18. ^ Pung, Y.F., Kumar, S.V., Rajagopalan, N., Fry, B.G., Kumar, P.P., Kini, R.M. 2006 Ohanin, a novel protein from king cobra venom: Its cDNA and genomic organization. Gene 371 (2):246–256
  19. ^ Rajagopalan, N., Pung, Y.F., Zhu, Y.Z., Wong, P.T.H., Kumar, P.P., Kini, R.M. 2007 β-Cardiotoxin: A new three-finger toxin from Ophiophagus hannah (King Cobra) venom with beta-blocker activity. FASEB Journal 21 (13):3685–3695
  20. ^ Chang, L.-S., Liou, J.-C., Lin, S.-R., Huang, H.-B. 2002Purification and characterization of a neurotoxin from the venom of Ophiophagus hannah (king cobra). Biochemical and Biophysical Research Communications 294 (3):574–578
  21. ^ Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals. Westport, Conn.Greenwood Press. ISBN 9780313339226.
  22. ^ National Geographic Program 17 May 2009

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