Thai National Parks

Reptiles of Thailand

Species of Thailand

Red-necked keelback

Thai: งูลายสาบคอแดง, ngu lai saap khor daeng

Binomial name: Rhabdophis subminiatus, Hermann Schlegel, 1837

Rhabdophis subminiatus, commonly called the red-necked keelback, is a species of venomous snake in the family Colubridae. The species is endemic to Asia.


R. subminiatus has a greenish hue with red and yellow regions near the head. It grows to 70 to 90 cm round=0.5 in total length (including tail).

Habitat and diet

The red-necked keelback generally lives near ponds, where it consumes frogs and fish.

Snakebite and Venom

Rhabdophis subminiatus is a rear-fanged species and was previously thought to be harmless. However, following one fatal and several near-fatal envenomations, the toxicity of its venom was investigated. As a result, it has recently been reclassified as a dangerous species. Rear-fanged snakes need to bite and hold on, or repeatedly bite, to have any effect on humans. A chewing action facilitates envenomation as the venom ducts open to fangs that are externally grooved (not hollow) and are posterior in the oral cavity.R. subminiatus has enlarged and non-grooved teeth. R. subminiatus has two enlarged teeth in the back of the snake’s jaw. Located in the upper jaw is a gland known as the Duvernoy's glands which produces an extremely venomous secretion.

Symptoms caused by venom

When the snake bites, the salivary venom mixture is not injected, but it flows into the punctures produced by the upper jaw’s rear teeth of R. subminiatus, which can penetrate the skin of humans. The venom from R. subminiatus has been responsible for internal hemorrhaging, including hemorrhaging of the brain. As well as nausea, coagulopathy, and even disseminated intravascular coagulation. Also, when the venom was tested on animals, renal failure was reported. Caution should be taken when dealing with patients who have been bite by the red-necked keelback snake. There should be no further injury such as injections because this may cause excessive bleeding in the bite victim. Although most human bites from R. subminiatus are involved with the front teeth and do not cause adverse effects, rare bites from the rear fangs can be lethal.


Two subspecies are recognized as being valid, including the nominotypical subspecies.

  • Rhabdophis subminiatus helleri
  • Rhabdophis subminiatus subminiatus

The trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Rhabdophis.


The subspecific name, helleri, is in honor of American zoologist Edmund Heller.

Geographic range

The red-necked keelback can be found in the following areas of the world:

  • Indonesia (Sumatra, Borneo, Java, Sulawesi ?)
  • Thailand, Vietnam, Cambodia, Laos, Burma
  • West Malaysia, Bhutan, Bangladesh, Nepal
  • India (Assam, West Bengal district, Sikkim; Arunachal Pradesh Itanagar - Papum Pare district, Mizoram a typo|Selesih}}, World Bank Road)
  • China (Yunnan, Guangxi, Guangdong, Fujian, Hong Kong, Hainan)

The subspecies R. s. helleri can be found in the following locations:

  • Bangladesh
  • Hong Kong
  • India (West Bengal-Jalpaiguri)
  • Laos
  • Myanmar
  • Nepal
  • People's Republic of China
  • Thailand
  • North Vietnam
  • South Vietnam

This article uses material from Wikipedia released under the Creative Commons Attribution-Share-Alike Licence 3.0. Eventual photos shown in this page may or may not be from Wikipedia, please see the license details for photos in photo by-lines.

Site notes

This species has nuchal glands, one of very few species of snakes in the world which is both venomous and poisonous. The only other species in Thailand which has nuchal glands is Rhabdophis nigrocinctus in same genus.

Scientific classification

Rhabdophis subminiatus

Common names

  • German: Rothals-Wassernatter
  • English: Red-necked keelback
  • Thai: งูลายสาบคอแดง, ngu lai saap khor daeng


  • Rhabdophis subminiatus helleri, Karl Patterson Schmidt, 1925

  • Rhabdophis subminiatus subminiatus, Hermann Schlegel, 1837


  • Rhabdophis subminiatus, Van Stanley Bartholomew Wallach et al. (2014)
  • Rhabdophis subminiatus helleri, Nguyen Van Sang et al. (2009)
  • Rhabdophis subminiata, R. C. Sharma (2004)
  • Rhabdophis subminiatus, Merel J. Cox et al. (1998)
  • Rhabdophis subminiatus, Ulrich Manthey & Wolfgang Grossmann (1997)
  • Rhabdophis subminiatus helleri, Ermi Zhao et al. (1986)
  • Rhabdophis subminiatus subminiatus, Edward Harrison Taylor (1965)
  • Rhabdophis subminiata helleri, Edward Harrison Taylor (1965)
  • Rhabdophis subminiata, E. V. Malnate (1960)
  • Natrix subminiata, Malcolm Arthur Smith (1943)
  • Rhabdophis himalayanus laobaoensis, fide Malcolm Arthur Smith (1943)
  • Rhabdophis subminiatus subminiatus, René Léon Bourret (1936)
  • Rhabdophis subminiatus, René Léon Bourret (1936)
  • Natrix subminiata subminiata, R. Mell (1931)
  • ?Natrix subminiata hongkongensis, R. Mell (1931)
  • Natrix subminiata helleri, R. Mell (1931)
  • Rhabdophis subminiatus helleri, Karl Patterson Schmidt (1925)
  • Natrix helleri, Karl Patterson Schmidt (1925)
  • Natrix subminiata, Thomas Barbour (1912)
  • Tropidonotus subminiatus, Frank Wall (1908)
  • Pseudoxenodon intermedius, Axel Johan Einar Lönnberg (1899)
  • Tropidonotus subminiatus, George Albert Boulenger (1893)
  • ? Tropidonotus manadensis, Albert Charles Lewis Günther (fide Van Stanley Bartholomew Wallach) (1873)
  • Tropidonotus subminiatus, Albert Charles Lewis Günther (1858)
  • Amphiesma subminiatum, André Marie Constant Duméril & Gabriel Bibron (1854)
  • Rhabdophis subminiatus, Leopold Fitzinger (1843)
  • Tropidonotus subminiatus, Hermann Schlegel (1837)
  • Natrix subminiatus, Friedrich Boie (1827)

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)

Red-necked keelback

Red-necked keelback

Creative Commons Attribution-ShareAlike 4.0 International Thai National Parks

Rhabdophis subminiatus

Rhabdophis subminiatus

Creative Commons Attribution-ShareAlike 4.0 International Thai National Parks

Rhabdophis subminiatus

Rhabdophis subminiatus

Creative Commons Attribution-ShareAlike 4.0 International Thai National Parks

Red-necked keelback

Red-necked keelback

Creative Commons Attribution-ShareAlike 4.0 International Thai National Parks

Distribution map of Red-necked keelback, Rhabdophis subminiatus in Thailand
  • Ban Chang District, Rayong
  • Ban Khok District, Uttaradit
  • Ban Lat District, Phetchaburi
  • Bang Lamung District, Chonburi
  • Bo Thong District, Chonburi
  • Chiang Dao Wildlife Sanctuary
  • Damnoen Saduak District, Ratchaburi
  • Doi Ang Khang
  • Doi Inthanon National Park
  • Doi Pha Hom Pok National Park
  • Doi Suthep-Pui National Park
  • Don Sak District, Surat Thani
  • Hang Dong District, Chiang Mai
  • Hot District, Chiang Mai
  • Huai Kha Khaeng Wildlife Sanctuary
  • Kaeng Krachan District, Phetchaburi
  • Kaeng Krachan National Park
  • Kaeng Tana National Park
  • Khao Chong
  • Khao Lak - Lam Ru National Park
  • Khao Lampi-Hat Thai Mueang National Park
  • Khao Luang National Park
  • Khao Phra - Bang Khram Wildlife Sanctuary
  • Khao Soi Dao Wildlife Sanctuary
  • Khao Sok National Park
  • Khao Yai Da
  • Khao Yai National Park
  • Khlong Saeng Wildlife Sanctuary
  • Ko Chang District, Trat
  • Ko Lanta District, Krabi
  • Ko Samui District, Surat Thani
  • Lam Plai Mat District, Buriram
  • Lan Sak District, Uthai Thani
  • Mae Sai District, Chiang Rai
  • Mueang Chiang Rai District, Chiang Rai
  • Mueang Krabi District, Krabi
  • Mueang Lampang District, Lampang
  • Mueang Nan District, Nan
  • Mueang Phichit District, Phichit
  • Mueang Ranong District, Ranong
  • Mueang Rayong District, Rayong
  • Nam Nao National Park
  • Nam Pat District, Uttaradit
  • Nam Som District, Udon Thani
  • Pai District, Mae Hong Son
  • Pak Chong District, Nakhon Ratchasima
  • Pak Tho District, Ratchaburi
  • Pak Thong Chai District, Nakhon Ratchasima
  • Phu Khiao Wildlife Sanctuary
  • Phu Luang Wildlife Sanctuary
  • Phu Wua Wildlife Sanctuary
  • Pua District, Nan
  • Sai Yok District, Kanchanaburi
  • Sai Yok National Park
  • Sakaerat Environmental Research Station
  • Samoeng District, Chiang Mai
  • Sangkhla Buri District, Kanchanaburi
  • Sattahip District, Chonburi
  • Si Racha District, Chonburi
  • Suan Phueng District, Ratchaburi
  • Tha Mai District, Chanthaburi
  • Thong Pha Phum District, Kanchanaburi
  • Thong Pha Phum National Park
  • Umphang Wildlife Sanctuary
  • Yan Ta Khao District, Trang
  • Yod Dom Wildlife Sanctuary

Range map of Rhabdophis subminiatus in Thailand

Important note; our range maps are based on limited data we have collected. The data is not necessarily accurate or complete.

Special thanks to Ton Smits, Parinya Pawangkhanant, Ian Dugdale and many others for their contribution for range data.

It is free to use this map on various media. See the creative common license terms by clicking "CC" icon below the map. But remember, again; the map may not be accurate or complete.

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