Bungarus

Bungarus is a genus of venomous elapid snakes found in India and South-East Asia. Commonly referred to as kraits, there are 12 species and 5 subspecies.

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Distribution

Kraits are found in the Indian subcontinent (including Sri Lanka and eastern Pakistan) and southeast Asia (including Indonesia and Borneo).^[1]

Description

Kraits usually range between 1 to 1.5 m in length, although specimens as large as 2 m have been observed. The Banded Krait (B. fasciatus) may grow as large as 2.5 m. Most species of krait are covered in smooth glossy scales that are arranged in bold striped patterns of alternating black and light-colored areas. This gives the snake camouflage in its habitat of grassland and scrub jungle. The scales along the dorsal ridge of the back are hexagonal. The head is slender and the eyes have round pupils. Kraits have a pronounced dorso-lateral flattening, and are triangular in cross-section. The tail tapers to a thin point.

Reproduction

Kraits are oviparous and the female will lay a clutch of 6 to 12 eggs in piles of leaf litter and stay with them until they hatch.

Diet & Behavior

Kraits are ophiophagous, preying primarily upon other snakes (including venomous varieties) and are cannibalistic, feeding on other kraits. They will also eat small lizards.^[2]

All kraits are nocturnal. The snake is more docile during the daylight hours, becoming more aggressive during the night. However, they are rather timid and will often hide their heads within their coiled bodies for protection. When in this posture, they will sometimes whip their tail around as a type of distraction.^[3]

Venom

Bungarus species contain neurotoxic venom that is 16 times more potent than cobra venom. Krait venom is extremely powerful and quickly induces muscle paralysis. Clinically, their venom contains mostly pre-synaptic neurotoxins. These affect the ability of nerve endings to properly release the chemical that sends the message to the next nerve. Following envenomation with bungarotoxins, transmitter release is initially blocked (leading to a brief paralysis), followed by a period of massive overexcitation (cramps, tremors, spasms), which finally tails off to paralysis. Not all these phases may be seen in all parts of the body at the same time. Fortunately, since kraits are nocturnal they seldom encounter humans during daylight hours so bites are rare. Nonetheless, any bite from a krait is potentially life-threatening and must therefore be regarded as a medical emergency. Note that there is frequently little or no pain at the site of a krait bite and this can provide false reassurance to the victim. Typically, victims start to complain later of severe abdominal cramps accompanied by progressive muscular paralysis, frequently starting with ptosis. As there are no local symptoms, a patient should be carefully observed for tell-tale signs of paralysis (eg the onset of ptosis, diplopia and dysphagia) and treated urgently with antivenom. Before antivenom was developed, there was an 85% mortality rate among bite victims.^[4] Krait antivenom is often ineffective and as a result, mortality rate is at 50% even with treatment.^[5] Because of this, it is sometimes arguably considered the world's most dangerous snake. Note that it is also possible to support bite victims via mechanical ventilation, using equipment of the type generally available at hospitals. Such support should be provided until the venom is metabolised and the victim can breathe unaided. If death occurs it takes place approximately 6 to 12 hours after the krait bite. Cause of death is respiratory failure ie suffocation via complete paralysis of the diaphragm.

In 2001, herpetologist Dr. Joe Slowinski was bitten by a juvenile krait (B. multicinctus) while doing field research in Myanmar. He was unable to reach medical assistance and subsequently died from the effects of the bite.

Species

*) Not including the nominate subspecies (typical form).

Kraits in fiction

Kraits have reputations as deadly snakes and has figured in fiction as such. Rudyard Kipling used a small, sand colored krait as one of the three main villains in his short story Rikki-Tiki-Tavi. (The other two villains being a couple of Black Cobras)

Roald Dahl uses the krait as a device in his short story "Poison." The krait also appears in Frederick Forsyth's short story "There Are No Snakes in Ireland" (included in his collection No Comebacks).

It has also been argued that the deadly snake in the Sherlock Holmes story The Adventure of the Speckled Band may have been a krait, although it is described in that work as an "Indian swamp adder." (The Russell's Viper has also been considered as a possible culprit.)^[6]

In a slightly more oblique reference, the motion picture Snakes on a Plane features a villainous snake smuggler named "Kraitler." ^[7]

In Dean Koontz's "The Good Guy", the hitman assigned to murder one of the protagonists calls himself Krait.

In Guild Wars Eye Of the North there is a race of snake-like creatures called Krait.

References

1. ^ SurvivalIQ: Krait
2. ^ Richard Mastenbroek's Elapid Pages: Kraits (Bungarus ssp.)
3. ^ Living in Indonesia:Banded Krait
4. ^ Immediate First Aid for bites by Kraits (Bungarus species)
5. ^ http://www.seanthomas.net/oldsite/danger.html
6. ^ Fauna in the Canon. strangemag.com.
7. ^ Snakes on a Plane. IMDb.

• EMBL Reptile Database: Family Elapidae
• Genus Bungarus at The Reptile Database
• Bungarus (TSN 700207). Integrated Taxonomic Information System. Accessed on 6 May 2006.