| banded krait | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subphylum: | Vertebrata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Elapidae |
| Genus: | Bungarus |
| Species: | B. fasciatus |
| Binomial name | |
| Bungarus fasciatus (Schneider, 1801) |
|
| Synonyms | |
The Banded krait (Bungarus fasciatus) is a species of genus Bungarus found in Indian Sub-continent, North Asia and Southeast Asia.[1] It is one of the largest kraits with a maximum length up to 2.1 meters (6 ft 11 in).[2]
Contents |
B. fasciatus is easily identified by its alternate black and yellow crossbands, its triangular body cross section, and the marked vertebral ridge consisting of enlarged vertebral shields along its body. The head is broad and depressed. The eyes are black. It has arrowhead-like yellow markings on its otherwise black head and has yellow lips, lores, chin and throat.[3]
The longest banded krait measured was 2.125 meters (6 ft 11.7 in) long, but normally the length encountered is 1.8 meters (5 ft 11 in).[2]
The snake has an entire anal plate and single subcaudals. The tail is small and ends like a finger-tip, generally being one tenth the length of the snake.[4]
The banded krait occurs in the whole of the Indo-Chinese subregion, the Malaysian peninsula and archipelago and Southern China.[2] The species is common in Assam and Bangladesh, but becomes progressively uncommon westwards in India.[3]
It has been recorded from eastwards from central India through through Myanmar, Cambodia, Thailand, Laos, Vietnam and southern China (including Hong Kong) to Malaysia and the main Indonesian islands of Borneo (Java and Sumatra), as well as Singapore. In India, it has been recorded from Northeast India, West Bengal, Orissa, parts of Maharashtra, Bihar, Jharkhand, Madhya Pradesh, Chhattisgarh and Andhra Pradesh. It has been recorded in Bihar and Orissa and as far south and west as Hyderabad and Warangal,[5] Awadh, the Godavari and Mahanadi valleys.[2] In Maharashtra it has been recorded in Chandrapur & Gadchiroli districts.[6]
Banded kraits may be seen in a variety of habitats, ranging from forests to agricultural lands. They inhabit termite mounds and rodent holes close to water, and often live near human settlement, especially villages, because of their supply of rodents and water. They prefer the open plains of the countryside.
The banded krait has been found in Myanmar up to an altitude of 5000 feet.[2]
Banded kraits are shy, not typically seen, and are mainly nocturnal. When harassed, they will usually hide their heads under their coils, and do not generally attempt to bite,[1] though at night they are much more active and widely considered to be more dangerous then.
During the day, they lie up in grass, pits or drains. The snakes are lethargic and sluggish even under provocation. They are most commonly seen in the rains.[3]
The banded krait feeds mainly on other snakes, but is also known to eat fish, frogs, skinks and snake eggs. Among the snakes taken by banded kraits are:[3] -
The prey is swallowed head first, after it has been rendered inactive by the venom.[3]
Little is known of its breeding habits. In Myanmar, a female has been dug out while incubating a clutch of 8 eggs, four of which hatched in May. Young have been recorded to measure 298 to 311mm on hatching. The snake is believed to become adult in the third year of its life, at an approximate length of 914mm.[7]
The venom of the banded krait mainly contains neurotoxins (Pre- and Post-synaptic neurotoxins) with LD50 values of 2.4 mg/kg[8]—3.6 mg/kg[9][10] SC, 1.289 mg/kg IV and 1.55 mg/kg IP.[9][10] The quantity of venom delivered averages out at 20—114 mg.[9] Engelmann and Obst (1981) list the venom yield at 114 mg (dry weight).[11] The major clincial effects caused by the venom of this species include vomiting, abdominal pain, diarrhoea, dizziness, etc. Severe envenomation can lead to respiratory failure and death may occur due to suffocation.[12] There are few authenticated records of human beings having been bitten.
A clinical toxinology study gives an untreated mortality rate of 1—10%, this may be due to the fact that contact with humans is rare and when bites do occur the rate of envenomation when biting defensively is thought to be very low.[1] Presently, a polyvalent antivenom developed by Alan Van Dyke is available in India.