| 1 | Indian krait |
One of the deadliest snakes in the world. Bungarus caeruleus (Indian krait) causes an estimated 15-30% of snakebites in India, 28% in Bangladesh, and 70-80% of untreated bites are fatal. This is part of the “big 4” of dangerous Indian snakes, also including saw-scaled vipers, Indian cobras, and Russell’s vipers.
Bungarus caeruleus measures 90-110cm (record 1.75m) and manifests in a variety of locations, from fields to agricultural areas to woodlands to villages. It eats a varied diet, but is particularly biased towards snakes, with meals including Whitaker’s sand boa and Brahminy’s blind snake. Bungarus caeruleus inhabits every region of India, as well as Sri Lanka. Its venom is strongly neurotoxic, containing both pre and post synaptic neurotoxins, preventing brain signals from being issued, and from binding to receptors in muscle cells.
The Indian krait is most disturbing for its completely painless bites, and lack of any local symptoms. Many victims are bitten while sleeping and have no idea what happened. This medical report followed an Indian army soldier on an exercise patrol in a forest, where he slept the night in a sleeping bag. The next day, all the muscles over his body were aching, and his head were pounding. He visited hospital, where his facial muscles were now stiff, his saliva was pooling inside his mouth, and he struggled to swallow. The doctors could find no bite mark anywhere, nor bleeding, and gave him 10 vials of combined cobra, krait and viper antivenom. The man recovered, and based on the symptoms, it was assumed to have been a Bungarus caeruleus bite, but never confirmed.
| 2 | Malaysian blue krait |
A common species of southeast Asia. The Malaysian blue krait (Bungarus candidus) inhabits most of Thailand, Vietnam, Cambodia, and peninsular Malaysia, and stretches southwards all the way to Java. Their habitats include deciduous and evergreen forests, and leafy villages on their outskirts. Like other Bungarus members, they’re active at night and sluggish by day.
This species is slightly weaker than its Indian cousin, at an LD50 rating of 0.1mg versus 0.9mg for Bungarus caeruleus. Yet this is only splitting hairs. The fact is that a Malaysian blue krait has a 70-80% chance of killing you without swift antivenom treatment. Bungarus candidus is rich in the bungarotoxins (neurotoxins) possessed by most of its family. It also has a unique toxin called candotoxin. The blue krait may be one of the deadliest, as a 2018 study analysed 78 confirmed krait victims from a Bangkok hospital. There were three species: blue kraits, banded kraits (Bungarus fasciatus) and red headed kraits (Bungarus flaviceps). 6 patients of the 78 died, and all were victims of the blue krait. This was despite every patient receiving antivenom.
The earliest symptoms include trouble swallowing and drooping eyelids (ptosis). Full body paralysis is normal, and artificial ventilation is a typical result. Luckily, Bungarus krait antivenom is well stocked in every Thai hospital. This species measures 100-150cm, with a record of 175cm.
| 3 | Banded krait |
An easily recognisable species, with its bright yellow bands, compared to white for most Bungarus family members. Banded kraits (Bungarus fasciatus) are one of the longer kraits, with a confirmed record so far of 225.5cm. The average is 120-150cm, and each yellow and black band is roughly equal in size.
Banded kraits have an LD50 rating of 1.2mg, making them slightly less fatal than blue kraits. Yet their venom still injects a multitude of neurotoxins in a fraction of a second, which unleash dizziness, vomiting, abdominal pain and respiratory failure. Banded kraits are extremely widespread and live alongside Malaysian blue kraits in most of its range. Their realms are similar: Thailand, Cambodia, Vietnam, and peninsular Malaysia, but this species spreads further westwards, reaching eastern India, and further along the southern Chinese coast, reaching Hong Kong.
Habitats of the banded krait include woodland and agricultural areas, normally near water sources, at altitudes of up to 2300 metres. Its likely that there’s subtle habitat differences to the blue krait which haven’t been discovered yet, allowing the two species to coexist in Thailand.
Bungarus fasciatus has a very flexible diet. Mammals, rodents and fellow snakes are all on the menu, including common wolf snakes and oriental ratsnakes. One captive banded krait even gobbled down a sausage.
| 4 | Greater black krait |
One of the less common Bungarus members. Black kraits (Bungarus niger) live in northeast India, Bhutan and Bangladesh. A lack of yellow-white bands is their signature feature, with a fully black body contrasting against a paler belly. The greater black krait was originally discovered in 1908, in the Darjeeling District of West Bengal. This is a shorter species, reaches a maximum of 120cm. This is another nocturnal species, which is most commonly encountered from 18:00-02:00, and inhabits evergreen forest, plantations, open grassland and villages.
Being nocturnal, and almost fully black, this krait can be very difficult to spot. This species is equally as nasty as its cousins. A study examined 5 bite victims from Bangladesh, proven by direct examination of the responsible snake. One victim suffered paralysis, and later kidney failure, which proved fatal. He also experienced rhabdomyolysis, the destruction of muscle tissue causing an increase in the bloodstream biomarker creatine kinase. Assaults on muscle tissue (myotoxicity) are rare for the Bungarus family. Another patient experienced paralysis, to which he succumbed. Another 3 paralysis patients recovered, including one who was placed on artificial ventilation.
Confirmed prey include radiated ratsnakes, mizo rain snakes and common mock vipers. Black kraits can also eat venomous snakes, as in captivity, one swallowed a juvenile red-tailed bamboo pitviper (Trimeresurus erythrurus).
| 5 | Andamam krait |
The resident terror of India’s Andamam and Nicobar Islands. These islands are located closer to Thailand than India, yet are officially part of the latter. Bungarus andamanensis is common in rice paddy fields, and on roads at night, particularly after heavy rains. They can be found in forests in mountainous areas as well as near coasts, and some lurk inside termite mounds.
Bungarus andamanensis is one of the least researched kraits. Virtually nothing is known about its venom, through researchers have witnessed its defensive style. A scared Andamam krait will coil itself up and hide its head, remain still, and produce a strange squeaking sound. This snake averages at 90cm, with a maximum of 130cm.
Like banded kraits, Andamam kraits have yellow bands instead of black, but this time, the yellow is far thinner than the black. There are no other kraits on the Andamam and Nicobar Islands, making this species easy to recognise. Its diet is poorly researched, but it has been seen swallowing water snakes, in the streams it tends to live next to.
| 6 | Northeastern hill krait |
A rarely observed species which lives far from cities and towns. Bungarus bungaroides lives in southeast Tibet, northeast India, eastern Nepal and Bhutan. It’s another poorly researched member, which reaches a current record of 1.45 metres. Bungarus bungaroides lives at up to 2400 metres, and as low as 250 metres, in submontane forests on the foothills of the Himalaya. It’s a purely black and white species, with extremely thin white bands, some so thin that it resembles a starry night.
Bungarus bungaroides possesses the lethal post and pre-synaptic neurotoxins of other kraits, but reportedly has a milder disposition. It’s reluctant to bite, even when persistently provoked. A spooked northeastern hill krait will coil loosely and attempt to hide its head.
Virtually no studies exist, whether on its ecology or diet. As the picture above shows, this species has a clear iridescent sheen. Though mainly a ground-dwelling snake, they’ll sometimes climb small shrubby branches, possibly to analyse animal scents. Overall, this species remains one of the snake kingdom’s mysteries.
| 7 | Sind krait |
The Sind krait lives in northwest India, Pakistan and Afghanistan, and is often confused with the Indian krait, which it overlaps with in parts of India. The two have a close resemblance, with only subtle differences, including 17 dorsal scale rows in the Sind krait versus 15 in the Indian. Sind kraits measure 100cm, reaching 180cm, and are just as deadly as Indian kraits, though less common.
An analysis of Bungarus sindanus venom revealed 36 distinct proteins from 8 separate toxin families. Its venom mainly contained three-finger toxins and phospholipase A2s. The venom was extremely lethal in mice. This species lacks a specific antivenom, and the scientists gave mice Indian VINS Polyvalent Antivenom, the elixir found in most hospitals, produced using each member of the big 4, including Indian kraits. This disabled some of the Sind krait toxins, saving the mice from death. However, the recovery time was long.
As usual, this species is active at night. Two proven bites happened to construction workers in Pune District, Maharashtra State, India, who were sleeping in makeshift huts at night. One victim developed neuromuscular paralysis, and abdominal pain, followed by 6 days of artificial ventilation. One of the Sind krait’s subspecies, Bungarus sindanus razai, is found only in northern Pakistan.
| 8 | Red-headed krait |
One of the most southerly kraits. Red-headed kraits (Bungarus flaviceps) begin in southern Thailand, and cover most of Malaysia as well as Singapore, Java and Sumatra. This species is sighted much more rarely than its cousins. Bungarus flaviceps mainly lives in densely forested lowlands and humid premontane forests, below 900 metres in altitude. They’re found near forest streams and pools, and invade homes far less commonly than other species.
Bites are also rarer. Red-headed krait venom is similarly neurotoxic, consisting of 56.2% beta-bungarotoxin, a form also found in many-banded kraits. This is a pre-synaptic neurotoxin, which are significantly hard to treat than post-synaptic neurotoxins, as they cut off neurological signals being issued. Another 12.85% of their venom consists of metalloproteinases, which physically destroy proteins. This species has no specific antivenom. A 2022 study found that antivenom for blue kraits was significantly more successful than banded kraits, so there was likely more toxin overlap.
Red-headed kraits average at 100-120cm, with an alltime record of 195.5cm. This is a distant offshoot within the krait family, splitting off before most other members. The red head is a simple way to identify Bungarus flaviceps, but not always. This species is deadly enough to have several mimics in Thailand/Malaysia. The likes of pink-headed reed snakes copy its colour pattern to gain a cushion of safety.
| 9 | Suzhen’s krait |
A new species, made official in 2015. Suzhen’s krait (Bungarus suzhenae) was encountered by herpetologists in 2001, but assumed to be a many-banded krait (Bungarus multicinctus) member. The grisly encounter happened to famous herpetologist Joseph Slowinski, who was bitten in Myanmar while handling the snake and died 29 hours later. Nobody knew it was a new species, until an detailed analysis in 2015 revealed several subtle differences.
Bungarus suzhenae had fangs which were only slightly curved backwards, versus noticeably curved for the many-banded krait. The shape of the patterns was unique, as the white bands were messier, less orderly. Bungarus suzhenae also has a completely pale belly, while many-banded kraits have a pale belly scattered with brown markings. Finally, the maximillia teeth are differently shaped.
The two species were separated, with Bungarus suzhenae officially inhabiting northern Myanmar and southwestern China, including in Yunnan province. This is a snake of rice fields and forested streams, at elevations of 800 to 1560 metres. Its wild diet is completely unknown. However, there are clues from captivity, where a Suzhen’s krait happily accepted an Asian swamp eel and yellow-spotted keelback water snake, but refused mice and frogs.
| 10 | Many-banded krait |
This species has the most powerful Bungarus krait venom of all, with an LD50 rating of 0.07mg, saved only by a weak venom yield of 7mg per bite. This is the most easterly member of the Bungarus family. Many-banded kraits have small pockets of territory in Thailand, but are most common along the southern Chinese coast, and especially in Hong Kong and Taiwan, where they’re statically one of the top venomous snakes, which all citizens are instructed to avoid from a young age. While the colouring is similar to other members, the clue is in the name – Bungarus multicinctus is distinguished by its thinner bands and unusually higher number of bands, at 42-60.
Over 50% of its venom consists of beta-bungarotoxins, a potent presynaptic neurotoxin. Another large chunk are alpha-neurotoxins, which are post-synaptic neurotoxins, meaning that many-banded kraits possess the complete neurotoxic package. Early symptoms include nausea, vomiting, dilated pupils and intense muscle aches. A 2017 study from Taiwan found that 27% of patients developed respiratory failure within 1.5-6.5 hours.
Like usual, this is a nocturnal species. If you walk past a dozing many-banded snake during daylight, they’ll likely barely react, sometimes not budging even if touched (which we don’t recommend in any circumstances). By night, they’re alert and focussed, and will respond viciously to anybody invading their personal space. Beware the many-banded krait’s neck, as it can bend at extreme angles, which make picking one up extremely unwise.