Species of Thailand

Red-necked keelback

Rhabdophis subminiatus, Hermann Schlegel, 1837

(In Thai: งูลายสาบคอแดง, ngu lai saap khor daeng)

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 subminiata helleri, Edward Harrison Taylor (1965)
  • Rhabdophis subminiatus subminiatus, Edward Harrison Taylor (1965)
  • Rhabdophis subminiata, E. V. Malnate (1960)
  • Rhabdophis himalayanus laobaoensis, fide Malcolm Arthur Smith (1943)

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)


Please help us review our species pages if wrong photos are used or any other details in the page is wrong. We can be reached via our Facebook group or contact us page.

Red-necked keelback
Rhabdophis subminiatus
Rhabdophis subminiatus
Red-necked keelback

Range Map

Distribution map of Red-necked keelback, Rhabdophis subminiatus in Thailand
  • Amphawa District, Samut Songkhram
  • Ban Chang District, Rayong
  • Ban Khai District, Rayong
  • Ban Khok District, Uttaradit
  • Ban Lat District, Phetchaburi
  • Bang Lamung District, Chonburi
  • Bo Rai District, Trat
  • Bo Thong District, Chonburi
  • Chiang Dao Wildlife Sanctuary
  • Chiang Khan District, Loei
  • 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 Khoi District, Saraburi
  • 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
  • Khlung District, Chanthaburi
  • Klaeng District, Rayong
  • Ko Chang District, Trat
  • Ko Lanta District, Krabi
  • Ko Samui District, Surat Thani
  • Kra Buri District, Ranong
  • Kuchinarai District, Kalasin
  • Lam Plai Mat District, Buriram
  • Lan Sak District, Uthai Thani
  • Mae Sai District, Chiang Rai
  • Muak Lek District, Saraburi
  • Mueang Bueng Kan District, Bueng Kan
  • Mueang Chanthaburi District, Chanthaburi
  • Mueang Chiang Rai District, Chiang Rai
  • Mueang Chumphon District, Chumphon
  • Mueang Krabi District, Krabi
  • Mueang Lampang District, Lampang
  • Mueang Nakhon Nayok District, Nakhon Nayok
  • Mueang Nan District, Nan
  • Mueang Phichit District, Phichit
  • Mueang Ranong District, Ranong
  • Mueang Rayong District, Rayong
  • Mueang Satun District, Satun
  • Mueang Trat District, Trat
  • Na Yai Am District, Chanthaburi
  • Nakhon Thai District, Phitsanulok
  • Nam Nao National Park
  • Nam Pat District, Uttaradit
  • Nam Som District, Udon Thani
  • Nikhom Nam Un District, Sakon Nakhon
  • Pa Bon District, Phatthalung
  • Pai District, Mae Hong Son
  • Pak Chong District, Nakhon Ratchasima
  • Pak Tho District, Ratchaburi
  • Pak Thong Chai District, Nakhon Ratchasima
  • Pho Sai District, Ubon Ratchathani
  • Phon Phisai District, Nong Khai
  • Phu Khiao Wildlife Sanctuary
  • Phu Luang Wildlife Sanctuary
  • Phu Wua Wildlife Sanctuary
  • Phuket Province
  • Plai Phraya District, Krabi
  • Pluak Daeng District, Rayong
  • Pua District, Nan
  • Rattaphum District, Songkhla
  • Sadao District, Songkhla
  • Sai Yok District, Kanchanaburi
  • Sai Yok National Park
  • Sakaerat Environmental Research Station
  • Samoeng District, Chiang Mai
  • Sangkhla Buri District, Kanchanaburi
  • Sattahip District, Chonburi
  • Sawi District, Chumphon
  • Si Racha District, Chonburi
  • Suan Phueng District, Ratchaburi
  • Takua Pa District, Phang Nga
  • Tha Mai District, Chanthaburi
  • Tha Takiap District, Chachoengsao
  • Thalang District, Phuket
  • Tham Phannara District, Nakhon Si Thammarat
  • Thong Pha Phum District, Kanchanaburi
  • Thong Pha Phum National Park
  • Thung Salaeng Luang National Park
  • Thung Song District, Nakhon Si Thammarat
  • Thung Tako District, Chumphon
  • Thung Yai Naresuan Wildlife Sanctuary
  • Umphang Wildlife Sanctuary
  • Wiang Kaen District, Chiang Rai
  • Yan Ta Khao District, Trang
  • Yod Dom Wildlife Sanctuary
Range map of Rhabdophis subminiatus in Thailand