One of 13 recognized Bungarus species, the Greater Black Krait (Bungarus niger) was described more than a century ago and is now known to be widely distributed in areas of high humidity and rainfall in northern India, Nepal, Bhutan, and Burma, occurring from mangroves at sea level to at least 1450m in the Himalayas. Investigations by Faiz et al. (2010) documented the presence of this species in Bangladesh as well.
Faiz et al. provide a detailed account of the medical consequences for humans bitten by B. niger and what is apparently the first published description of generalized rhabdomyolysis attributable to envenoming by any Asian or African terrestrial elapid snake. This rhabdomyolysis (rapid breakdown of skeletal muscle, with byproducts potentially causing kidney failure and other symptoms) is in addition to the more familiar respiratory failure associated with krait bite envenoming.
(Faiz et al. 2010 and references therein)
Bungarus niger is similar in appearance to the Lesser Black Krait (B. lividus), which appears to be its closest relative (Wall 1911; Slowinski 1994).
B. niger is medium in length, slender-bodied, and triangular in cross-section, with a short, pointed tail. It can grow to a maximum total length (including tail) of about 1.3 m (4.3 ft), but adults usually average around 0.8 m (2.6 ft). The head is flat and slightly distinct from the neck. The eye is small to medium in size, black with a round pupil. The dorsal scales are smooth and glossy, with scales of the vertebral row enlarged and hexagonal. The dorsal scale count is 15 - 15 - 15. It is syntopic with the lesser black krait (Bungarus lividus), but can be separated by the enlarged dorsal vertebral scales. The number of ventral and subcaudals are higher than in all other Bungarus species (216-231 ventrals and 47-57 subcaudals).
B. niger is found in India mainly along the sub-Himalayas from Uttarakhand in the west to Arunachal Pradesh as well as in Nepal, Bhutan, Pakistan and Bangladesh. The species was described by Frank Wall from a specimen obtained from near Tindharia near Darjeeling. The species is also found at Jalpaiguri town and other parts of the district. This species inhabits a wide variety of habitats from mangrove swamps to inhabited villages to montane forests up to elevations of 1,500 m (4,900 ft) above sea level on the Himalayan foothills.
A nocturnal and terrestrial snake, B. niger has an inoffensive disposition. When disturbed, it coils loosely and hides its head beneath its body. It is reluctant to bite except upon persistent provocation. It preys mostly on snakes and small mammals and occasionally lizards, frogs, and fish.
The venom of B. niger consists of both presynaptic and postsynaptic neurotoxins, and may also contain myotoxins. This snake is often overlooked, but it is a medically important species, as it has caused many bites. The mortality rate associated with it is not known, but is said to be quite high.