king cobra

King Cobra
Conservation status
Least Concern (IUCN 3.1)
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. The King cobra is not a kind of cobra at all; it belongs to its own 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 shape that may be seen in other cobras. 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). The venom of the King Cobra is primarily neurotoxic, and the snake is fully capable of killing a human with a single bite.^[2] The mortality rate from a bite can be as high as 75%.^[2][3][4]

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.^[5] Despite its large size, King Cobras are fast and agile. The skin 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. 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.

Habitat

The King Cobra is distributed across South and South-east Asia, but is not common. It lives in dense highland forests,^[1][6], 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.^[7]

Scalation of the King Cobra

Hunting

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^[8] and sensitivity to earth-borne vibration to track its prey.^[9] 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][2]

Diet

The King Cobra's diet is mainly composed of other snakes (ophiophagy): both non-venomous snakes such as pythons and venomous snakes including kraits^[2][10] 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][10] 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 which attract rats.

Defense

Adult male King Cobra

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 high as 7 feet.

If King Cobra encounters a natural predator, such as the mongoose, which has some resistance to the neurotoxins,^[11] 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.

Venom

The King Cobra's venom, which is composed mostly of proteins and polypeptides, is produced in specialized salivary glands (as is the case with all venomous reptiles) just behind the animal's eyes. When biting its prey, venom is forced through the snake's half-inch (1.25 cm) fangs and into the wound. In the past,King cobra was treated as 1.7 mg/kg in LD/50 value (which is one of the least toxic elapids.) However, this is not always true. According to the recent toxinology study, the LD/50 of Chinese King cobra is 0.34 mg/kg-0.46 mg/kg which means it is more poisonous than most of the other cobra species, like chinese cobra^[1]. Although this toxicity is still weaker than some of the other elapids(like taipan, krait,etc), King cobras can deliver larger quantities of venom than most other species. It injects 380-600 mg of venom(which is enough to kill 20-42 grown men) in a single bite, and can even kill an elephant within 3 hours. One bite from king cobra to human can cause death within 15 minutes.^[12][13]

The King Cobra's venom is primarily neurotoxic and thus attacks 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. 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.^[14] Ohanin, a protein component of the venom, causes hypolocomotion and hyperalgesia in mammals.^[15] Other components have cardiotoxic,^[16] cytotoxic and neurotoxic effects.^[17]

Despite the King Cobra's fearsome reputation and deadly bite, it is a shy and reclusive animal, avoiding confrontation with humans as often as possible.^[10] There are other venomous snakes within this species' range, in fact, that are responsible for more fatal snake bites than the King Cobra, such as the Monocled Cobra, or Russell's Viper .^[6]

In Burma, King Cobras are often used by female snake charmers.^[10] 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.^[10] The charmer kisses the snake on the top of its head at the end of the show.^[10]

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.^[18]

Inside the mound that the female has built the eggs are incubated at a steady 28℃. 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.^[19] The baby king cobras can have a length of 55 cm, and have already developed potent venom which is as deadly as that of an adult.

Related species

The King Cobra belongs to the family Elapidae. There are over 200 species of elapid found around the world, excepting 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.

Gallery

King Cobra Village (Ban Khok Sangha), Thailand|	King Cobra Village (Ban Khok Sangha), Thailand|	St. Louis Zoo
	South Indian King Cobra	King Cobra in the wild from Agumbe in South India

References

External links

Wikispecies has information related to: Ophiophagus hannah

Wikimedia Commons has media related to: Ophiophagus hannah

• Real Audio format of a King Cobra hissing