Common krait

Identification

The common krait is a slender, smooth snake that is black or bluish-black above with narrow white crossbands, usually arranged more or less in pairs. The bands are faintest on the front part of the body and may be missing there; in older snakes they often break up into rows of small spots. The belly and upper lip are white¹.

Kraits have very glossy scales and a row of strongly enlarged scales running along the middle of the back. Large adults measure about 1.2 m in total length, and specimens of about 1.5 m have been recorded but are rare¹.

Distribution

The common krait is found in Afghanistan, Pakistan, India, Sri Lanka, Bangladesh and Nepal, and possibly Bhutan². In India it is widespread and mainly a snake of the plains, although it has been recorded as high as about 1,650 m at Almora in the Himalaya¹. In Sri Lanka it is common in the dry zone³.

A krait from Karnataka was described as a new species, Bungarus romulusi, in 2021, but the name was not validly published, so the Reptile Database currently includes these snakes in B. caeruleus².

Habitat

Kraits live in fairly open country at low elevations. They often visit cultivated land and are frequently found in and around houses and villages¹. In western India, common kraits are often found near water in forested areas, but they adapt readily to changed habitats such as farms and gardens⁴.

During the night they may enter homes while searching for prey⁵.

Behaviour

The common krait is mainly nocturnal and is often seen at night when it enters houses or crosses roads⁴. When disturbed it is usually quiet and reluctant to bite; it may coil loosely and hide its head under its body instead of striking¹.

Most krait bites in South Asia happen at night to people sleeping in their homes, usually on the floor, when a person rolls onto a krait that has come inside⁵. WHO guidance notes that sleeping under a mosquito net that is well tucked in also protects against snakes⁵.

Diet

Kraits feed mainly on other snakes and will eat both harmless and venomous species. Small mammals, lizards and frogs are also taken¹. Field reports from India describe common kraits eating snakes, lizards, frogs and mice, and scavenging snakes and rodents killed on roads⁴.

In 2022 a young common krait in Gujarat, India, was seen swallowing a saw-scaled viper, the first published record of this prey⁶.

Reproduction

The common krait lays eggs². A clutch usually holds about 6–10 eggs, laid in holes in the ground or under leaves, and the parent guards them afterwards¹.

In India eggs are laid in April and May, and the young hatch from May to July. Hatchlings measure about 26–28 cm and can grow nearly 30 cm in their first year¹.

Venom and medical significance

The common krait is one of India’s “big four” medically important snakes⁵. Its venom is mainly neurotoxic. A krait bite may be almost painless and cause little or no swelling; a sleeping person may not even wake up, and fang marks can be hard to see. Envenoming can cause drooping eyelids and paralysis that spreads through the body and can stop breathing⁵.

In a Sri Lankan study of 210 people bitten at night while asleep on the floor, abdominal pain was the main early symptom, 48% needed a breathing machine and 7.6% died³. Anyone who may have been bitten must go to hospital immediately, even if they feel no pain⁵.

Conservation

The common krait is listed as Least Concern on the IUCN Red List (assessed 2021)⁷. It is common in many parts of India¹.

In India it is protected under Schedule II of the Wild Life (Protection) Act, 1972, as amended in 2022, which covers all elapid snakes not listed in Schedule I⁸.

Similar species

The harmless common wolf snake (Lycodon aulicus) is often confused with the common krait. WHO guidelines note that wolf snakes mimic kraits, and mistaken identification can lead to unnecessary antivenom treatment⁵.

Some visual differences: the krait is glossy black or bluish-black with thin white bands that are often paired, while the wolf snake is brown or greyish-brown with white bands that widen or fork on the sides. The wolf snake usually has a whitish patch on the back of the head and a flattened snout that projects beyond the lower jaw¹. These differences are not a safe basis for handling any snake.

In captivity

The common krait is highly venomous and is not suitable as a pet. In India it is listed in Schedule II of the Wild Life (Protection) Act, 1972 (as amended in 2022), and the Act prohibits hunting animals listed in Schedules I and II⁸.

Because kraits often enter houses at night, WHO advises checking homes for snakes and removing hiding places such as rubbish heaps and building materials near the house⁵.