Thursday, 2 May 2013

KRAIT

COMMON KRAIT

The common krait (Bungarus caeruleus, also known as Indian krait or Blue krait) is a species of genus Bungarus found in the jungles of the Indian subcontinent.[1] It is a member of the "big four", species inflicting the most snakebites in India.

 

 Description

The Common Krait
The average length is 0.99 meters (3 ft 3 in) but they can grow to 1.75 meters (5 ft 9 in).[1] Males are longer with proportionately longer tails. The head is flat. Neck hardly evident. The body is cylindrical, tapering towards the tail. The tail is short and rounded. The eyes are rather small, with rounded pupils, indistinguishable in life. The head shields are normal, no loreals; four shields along the margin of the lower lip; 3rd and 4th supraoculars touching the eye. Scales are highly polished, in 15-17 rows; the vertebral row is distinctly enlarged and hexagonal. Ventrals 185-225. Caudals 37-50, entire.[2]
Colouration is generally black or bluish black, with about 40 thin, white crossbars which may be indistinct or absent anteriorly. The pattern however, is complete and well defined in the young which are marked with conspicuous crossbars even anteriorly; in old individuals the narrow white lines may be found as a series of connected spots, with a prominent spot on the vertebral region. A white preocular spot may be present: upper lips and the belly are white.[2]

 Common names

  • Hindi - करैत (Karait).
  • Bengali - Kalach, ডোমনাচিতি (Domnachiti) (North Bengal), শঙ্খিনি (Shankhani) (North Bengal), শিয়ার চাঁদা (Shiyar Chanda) (South Bengal). কেউটে (Keutay) or শাহ-কানন (Shah-Kanon)(Bangladesh)
  • Kannada - Kattige haavu.
  • Telugu - Katla paamu.
  • Gujarati - Kalo taro.
  • Rajsthani - Peewano.
  • Marathi - Manyar, kanadar.
  • Oriya - ଚିତି (Chitti).
  • Tamil - Kattu viriyan, Pudayan,
  • Malayalam - Velli Kattan (Malabar and Cochin), Ettadi veeran (Travancore).
  • Sinhala - Karawala.
  • Tulu - Katta Kadambale.
  • Urdu - کلوٹاڑو یا کریت

Geographic range

Peninsular India from Sindh (Pakistan), to the West Bengal plains. It occurs throughout South India and Sri Lanka at elevations up to about 1600 metres.[1]

 Habitat

Inhabits a wide variety of habitat in its range. It is found in fields, low scrub jungle as well as inhabited areas. They are known to take up residence in termite mounds, brick piles, rat holes and also inside houses.[1] It is fond of water and is frequently found in it or within proximity to a water source.

 Feeding

These snakes prey on other snakes, lizards, frogs, rats, and mice. They will devour their young being cannibalistic in nature. Young are known to eat arthropods. As per Daniels, the common krait feeds primarily on other snakes, including "blind worms" (snakes of the genus Typhlops) and other kraits, and also feeds on frogs and lizards and small mammals. This snake is nocturnal. It is very active and agile at night. It often hides in rodent holes, loose soil or beneath debris, so it is rarely seen during day.
Common Krait(Bungarus caeruleus) eating a wolf snake(Lycodon aulicus)

 Behavior

Behavioral differences during day and nighttime have been reported in Bungarus caeruleus. During the day it is sluggish and rolls its body into a loose coiled ball, keeping its head well-concealed. In balled condition, the snake allows considerable handling, however, over handling often instigates bites. At night the snake is very active, escapes by hissing loudly, or keeping still, occasionally biting the source of the annoyance.
When agitated, it will coil up with head concealed, body flattened, and make jerky movements. May also lift its tail. Reluctant to bite, but when it does bite, it typically bites and holds on for awhile, which enables it to inject considerable amounts of venom.They are generally docile and not aggressive during the day, it may become aggressive at night if threatened.

 Venom

The Indian krait's venom consists mostly of powerful neurotoxins which induce muscle paralysis. Clinically, its venom contains pre-synaptic and post-synaptic neurotoxins.[1] These neurotoxins generally affect the nerve endings near the synaptic cleft of the brain.
In mice, the LD50 values of its venom are 0.365 mg/kg SC, 0.169 mg/kg IV and 0.089 mg/kg IP.[3][4] while the average venom yield is 10 mg (dry weight).[5]
Kraits are nocturnal and seldom encounter humans during daylight hours, so incidents occur mainly at night. There is frequently little or no pain from a krait bite and this can provide false reassurance to the victim. Typically, victims complain of severe abdominal cramps, accompanied by progressive paralysis. Once bitten, the absorption of the venom into the victim can be considerably delayed by applying a pressure bandage to the bite site (using about the same tension as one uses for a sprained ankle) and immobilising the area. This allows for gentle transport to medical facilities, where the venom can be treated when the bandage is removed. As there are no local symptoms, a patient should be carefully observed for signs of paralysis (e.g., the onset of ptosis) and treated urgently with antivenom. 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 4–8 hours after the krait bite. Cause of death is general respiratory failure, i.e. suffocation.[6]
Often during the rainy season, the snakes come out of their hiding places and find refuge inside dry houses. If bitten by a krait while sleeping, a victim may not realize he has been bitten as the bite feels like an ant bite or a mosquito bite. The victim may be dead before he even wakes up. One such case was recently reported in Indore. An English language accent instructor was bitten by a krait inside his house and was declared dead upon arrival at the hospital[citation needed].
There are few symptoms of having been bitten. The facial muscles get tight in 1-2 hours, the patient may be unable to talk or see, and, if left untreated, the patient may die from respiratory paralysis  

 

 Other culture

In the famous story in The Jungle Book, "Rikki Tikki Tavi," Karait, a dustbrown krait, threatens the boy. Rikki, a young mongoose does battle with the snake and the narrator emphasizes that he is a dangerous opponent, even more than a cobra in some respects. Regardless of the risk and the mongoose's inexperience, Rikki defeats him.
In the 9th novel of the Women's Murder Club, "8th Confession" by James Patterson, the killer used a krait snake to poison and kill her victims.
Roald Dahl's Someone Like You (collection) contains a short story called "Poison" in which a krait creeps up onto a man's stomach as he lies in bed reading a book.

No comments:

Post a Comment