Thai National Parks

Reptiles of Thailand

Species of Thailand

Pope's pit viper

Binomial name: Trimeresurus popeiorum (Malcolm Arthur Smith, 1937)

Trimeresurus popeorum is a venomous pit viper species native to northern India, Southeast Asia, and parts of Indonesia. Three subspecies are currently recognized, including the nominate subspecies described here.


Grows to a total length of 770 mm, 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. popeorum is T. s. yunnanensis (q.v.); ordinarily, the two are more easily told apart by the number of midbody dorsal scale rows, 21 in T. popeorum, 19 in T. s. yunnanensis.

Geographic range

Northern India, 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.

Taxonomy & Etymology

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.


T. popeorum is found in forests of mountainous regions.


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


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


This species 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.


T. popeorum 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: งูเขียวหางไหม้ท้องเขียวเหนือ


  • Trimeresurus popeorum barati (U. Regenass & Eugen Kramer, 1981) - Indonesia: Sumatra (Barat District), the Mentawai Archipelago (on Siberut, North Pagai and South Pagai), and Simeulue (Simalur).

    Common name(s): Barat pit viper

  • Trimeresurus popeorum popeorum (Malcolm Arthur Smith, 1937) - Northeastern India, Burma, Thailand, West Malaysia, Singapore and Laos.

    Common name(s): Pope's pit viper

  • Trimeresurus popeorum sabahi (U. Regenass & Eugen Kramer, 1981) - East Malaysia (Sabah and Sarawak) and Indonesia (Kalimantan).

    Common name(s): Sabah pit viper


  • Popeia popeiorum, Peng Guo et al. (2015)
  • Popeia popeiorum, Tanya Chan-Ard 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)
  • Trimeresurus popeiorum, Gernot Vogel et al. (2004)
  • Popeia popeiorum, Anita Malhotra & Roger Stephen Thorpe (2004)
  • Trimeresurus popeiorum, Tu et al. (2000)
  • Trimeresurus popeorum, Roy W. McDiarmid, Jonathan A. Campbell & T'Shaka A. Touré (1999)
  • Trimeresurus popeiorum, Merel J. Cox et al. (1998)
  • Trimeresurus popeorum, P. Hoffmann (1998)
  • Trimeresurus popeorum popeorum, Philippe Golay et al. (1993)
  • Trimeresurus popeorum popeorum, Urs Regenass & Eugen Kramer (1981)
  • Trimeresurus popeorum, Alice Georgie Cruickshank Grandison (1972)
  • Trimeresurus popeorum, Edward Harrison Taylor & Robert E. Elbel (1958)
  • Trimeresurus popeorum, Malcolm Arthur Smith (1943)
  • Trimeresurus popeiorum sic, Malcolm Arthur Smith (1937)
  • Trimeresurus popeiorum, Malcolm Arthur Smith (1937)
  • Trimeresurus gramineus (part), Clifford Hillhouse Pope & Sarah H. Pope (1933)
  • Trimesurus elegans (part), John Edward Gray (1853)

Pope's pit viper is found in following locations in Thailand

Please note that this non-official list is not complete nor necessarily accurate. This list is a summary of checklists from other websites, blogs, publications, photo/videos published on various websites or our own findings. We appreciate your contributions with photo proof.

Conservation status

Least Concern (iucn3.1)

Least Concern (iucn3.1)

Trimeresurus popeiorum (male)

Trimeresurus popeiorum (male)

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Trimeresurus popeiorum (female, in situ)

Trimeresurus popeiorum (female, in situ)

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Trimeresurus popeiorum (male)

Trimeresurus popeiorum (male)

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Trimeresurus popeorum (female)

Trimeresurus popeorum (female)

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Trimeresurus popeorum (male, juvenile)

Trimeresurus popeorum (male, juvenile)

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Trimeresurus popeiorum tail

Trimeresurus popeiorum tail

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Distribution map of Pope's pit viper, Trimeresurus popeiorum in Thailand

Range map of Trimeresurus popeiorum in Thailand

Important note; our range maps are generated automatically based on very limited data we have about the protected sites, the data is not necessarily accurate. Please help us to improve our range maps by sharing your findings/knowledge.