Thai National Parks

Species of Thailand

Pope's pit viper

Trimeresurus popeiorum, Malcolm Arthur Smith, 1937

(In Thai: งูเขียวหางไหม้ท้องเขียว, ngu khieow hang mai thong khieow)

Trimeresurus popeiorum is a species of venomous pit viper in the family Viperidae. The species is native to northern and northeastern parts of India, Southeast Asia, and parts of Indonesia. Common names include: Pope's pit viper, Pope's tree viper, and Pope's bamboo pitviper. Two subspecies are currently recognized, including the nominate subspecies described here.


Trimeresurus popeiorum may grow to a total length of 770 mm, which includes a tail length 170 mm.

Above green, below pale green to whitish, the two separated by a bright bicolored orange or brown (below) and white (above) (males) or white (females) ventrolateral stripe, which occupies the whole of the outermost scale row and a portion of the second row.

Dorsal scales in 21 (rarely 23) longitudinal rows at midbody; 9-11 upper labials, first upper labials separated from nasals by a distinct suture; a single supraocular. Ventrals 155-169; subcaudals 52-76, in males the base of the tail enlarged to the level of subcaudals 20-25; hemipenes long and slender, smooth, without spines.

This species is most often confused with T. s. stejnegeri (q.v.); the two have quite distinct hemipenes, which does not make identification of individuals in the field or in the laboratory any easier without recourse to (a) male individuals and (b) an examination of the hemipenes. However, the two species are not known to have overlapping distributions, at least based on available materials. Also, closely allied to T. popeiorum is Trimeresurus yunnanensis (q.v.); ordinarily, the two are more easily told apart by the number of midbody dorsal scale rows, 21 in T. popeiorum, 19 in T. yunnanensis.

Geographic range

Northern and northeastern India (Mizoram), Burma, Thailand, West Malaysia and Vietnam. In Indonesia, it occurs on the islands of Sumatra, Mentawai Islands (Siberut, Sipora, North Pagai) and Borneo. The type locality, designated by lectotype, is listed as "Khasi Hills, Assam" (India).

Gumprecht et al. (2004) consider records for Bangladesh, Cambodia and Vietnam to be highly questionable, as they are likely based on misidentifications involving other species of Trimeresurus.


Subspecies Taxon author Common name Geographic range
T. p. barati Regenass & Kramer, 1981 Barat pit viper Indonesia: Sumatra (Barat District), the Mentawai Archipelago (on Siberut, North Pagai and South Pagai), and Simeulue (Simalur).
T. p. popeiorum M.A. Smith, 1937 Pope's pit viper Northeastern India, Burma, Thailand, West Malaysia, Singapore and Laos.

Taxonomy and etymology

The specific name, popeiorum (Latin, genitive, plural), is in honor of two American herpetologists, Clifford H. Pope and Sarah H. Pope, his wife.

There are differences in opinion as to the correct spelling of the specific epithet. The following is from David and Vogel (1996):

This species was named in honour to Clifford H. Pope and Sarah H. Pope. The original spelling of the specific epithet, popeiorum, was corrected into popeorum by Smith (1943:518) on the basis that it was indeed a clerical error. Unfortunately, according to the Art. 32 (c, ii) of the Code (ICZN, 1985), such a change does not fall into the category of a “correction of an incorrect original spelling." According to the Art. 33 (d), the use of a termination -orum in a subsequent spelling of a species-group name that is a genitive based upon a personal name in which the correct original spelling terminates with -iorum, is an incorrect subsequent spelling, even if the change is deliberate. The original spelling, popeiorum, must therefore be conserved.


Trimeresurus popeiorum is found in forests of mountainous regions.


Trimeresurus popeiorum is nocturnal and arboreal. If threatened, it will vibrate its tail.


Trimeresurus popeiorum preys upon frogs, lizards, birds, and rodents (especially rats and squirrels).


This species, T. popeiorum, is viviparous. In India, sexually mature females give birth in April and May, and the average clutch size is 10. The hatchlings are about 180 mm long.


Trimeresurus popeiorum possesses a potent neurotoxic venom which is dangerous to humans.

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Scientific classification

Trimeresurus popeiorum

Common names

  • German:
    • Popes Bambusotter
    • Popes Lanzenotter
  • English:
    • Pope’s pit viper
    • Pope’s tree viper
    • Pope's bamboo pit viper
    • Red-eyed Pit Viper
  • Thai: งูเขียวหางไหม้ท้องเขียว, ngu khieow hang mai thong khieow


  • Trimeresurus popeorum barati, U. Regenass & Eugen Kramer, 1981

    Common name: Barat pit viper

    Range: Indonesia: Sumatra (Barat District), the Mentawai Archipelago (on Siberut, North Pagai and South Pagai), and Simeulue (Simalur).

  • Trimeresurus popeorum popeorum, Malcolm Arthur Smith, 1937

    Common name: Pope's pit viper

    Range: Northeastern India, Burma, Thailand, West Malaysia, Singapore and Laos.

  • Trimeresurus popeorum sabahi, U. Regenass & Eugen Kramer, 1981

    Common name: Sabah pit viper

    Range: East Malaysia (Sabah and Sarawak) and Indonesia (Kalimantan).


  • Popeia popeiorum, Tanya Chan-Ard et al. (2015)
  • Popeia popeiorum, Peng Guo et al. (2015)
  • Popeia popeorum, Van Stanley Bartholomew Wallach et al. (2014)
  • Trimeresurus (Popeia) popeiorum, Patrick David et al. (2011)
  • Trimeresurus popeiorum, Patrick David et al. (2009)
  • Popeia popeiorum, Larry Lee Grismer et al. (2006)
  • Popeia popeiorum, Anita Malhotra & Roger Stephen Thorpe (2004)
  • Trimeresurus popeiorum, Gernot Vogel et al. (2004)
  • Trimeresurus popeiorum, Tu et al. (2000)
  • Trimeresurus popeorum, Roy W. McDiarmid, Jonathan A. Campbell & T'Shaka A. Touré (1999)

Conservation status

Least Concern (iucn3.1)

Least Concern (iucn3.1)


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Trimeresurus popeiorum (female, in situ) - Doi Phu Kha NP
Trimeresurus popeiorum (female, in situ) - Kaeng Krachan NP
Trimeresurus popeiorum (female, in situ) - Kaeng Krachan NP
Trimeresurus popeiorum (male, southern variation)
Trimeresurus popeorum (female) - Kaeng Krachan NP
Trimeresurus popeiorum (male) - Kaeng Krachan NP
Trimeresurus popeorum (male, juvenile) - Kaeng Krachan NP
Trimeresurus popeiorum (tail) - Kaeng Krachan NP

Range Map

Distribution map of Pope's pit viper, Trimeresurus popeiorum in Thailand
  • Chae Son National Park
  • Chiang Dao District, Chiang Mai
  • Chiang Dao Wildlife Sanctuary
  • Doi Chang
  • Doi Inthanon National Park
  • Doi Luang National Park
  • Doi Phu Kha National Park
  • Doi Saket District, Chiang Mai
  • Doi Suthep - Pui National Park
  • Doi Tung
  • Fang District, Chiang Mai
  • Huai Kha Khaeng Wildlife Sanctuary
  • Huai Nam Dang National Park
  • Huai Yang Waterfall National Park
  • Kaeng Krachan National Park
  • Khun Chae National Park
  • Khun Nan National Park
  • Khun Phawo National Park
  • Kui Buri National Park
  • Mae Sariang District, Mae Hong Son
  • Mae Taeng District, Chiang Mai
  • Mae Wang District, Chiang Mai
  • Mae Wong National Park
  • Mueang Pan District, Lampang
  • Namtok Mae Surin National Park
  • Omkoi District, Chiang Mai
  • Phu Chi Fa Forest Park
  • Samoeng District, Chiang Mai
  • Suan Phueng District, Ratchaburi
  • Taksin Maharat National Park
  • Tha Song Yang District, Tak
  • Thong Pha Phum National Park
  • Thung Yai Naresuan Wildlife Sanctuary
  • Umphang District, Tak
Range map of Trimeresurus popeiorum in Thailand