Thai National Parks

Species of Thailand

Red-tailed tree snake

Gonyosoma oxycephalum, Heinrich Boie, 1827

(In Thai: งูเขียวกาบหมาก)

The red-tailed green ratsnake (Gonyosoma oxycephalum, also known as arboreal ratsnake and red-tailed racer) is a species of snake found in Southeast Asia.


It is a robust snake with powerful, smooth scales on its belly that is ideal for climbing trees and across branches. It has smaller, smooth scales on its back that is usually bright green or light green and may have black net-like pattern. A gray-colored morph with a yellow head exists in Panay, in the Philippines.

As its name indicates, the snake has a green body with a red tail but is usually brown. It also has a dark line horizontally across its eye. On the sides of its black tongue there may be a Brown and blue colour. The top of the head maybe dark green, yellow-green or yellow in colour.

The female can reach a length of up to 2.4 m (almost 8 feet), while the male is generally a little bit smaller but brighter in coloration. Its average life span in captivity is 20 years. It reaches sexually maturity at 4 years of age, and its eggs have a hatching time from 13 to 16 weeks. The female lays on average between 3 and 8 eggs usually between September and January and the hatchlings are about 45 cm (18 inches) long.


The red-tailed green ratsnake lives and spends its life in the trees and in cavities in trees. It seldom descends to the ground. When the snake is stressed, it may inflate a bag of air in its neck, making it appear larger in size.

In captivity, it has quite the 'attitude' and may strike at or bite an unwary handler. It's temperament can be unpredictable and may change from time to time but an individual may become tame through proper handling.


It feeds almost exclusively on birds, bird eggs and bats. It catches them in mid-air while hanging amongst branches. In captivity, it can be trained to feed on rodents such as mice and rats.


  • Indonesia (Bangka, Belitung, Java, Kalimantan/Borneo, Karimata, Legundi, Lombok, Mentawai islands, Natuna islands, Nias, Panaitan, Riau archipelago, Sebuku, Sumatra, Tambelan archipelago),
  • Malaysia (Malaya and East Malaysia, Pulau Tioman ?),
  • Singapore Island, Penang Island,
  • India (Andaman Islands),
  • Myanmar (= Burma),
  • Thailand (incl. Phuket), Cambodia, Laos, Vietnam,
  • Philippine Islands (Balabac, Bohol, Lubang, Luzon, Negros, Palawan, Sulu Archipelago, Panay)

Type locality Indonesia: Java (Boie, 1827)

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Scientific classification

Gonyosoma oxycephalum

Common names

  • German:
    • Spitzkopfnatter
    • Rotschwanznatter
  • English:
    • Red-tailed tree snake
    • Red-tailed racer
    • Red-tailed green ratsnake
  • Thai: งูเขียวกาบหมาก


  • Gonyosoma floweri, Tanya Chan-Ard et al. (2015)
  • Gonyosoma oxycephalum, Chen et al. (2014)
  • Gonyosoma oxycephalum, Maren Gaulke (2011)
  • Gonyosoma oxycephala, Frank T. Burbrink & R. Lawson (2007)
  • Elaphe oxycephala, R.C. Sharma (2004)
  • Gonyosoma oxycephala, Maren Gaulke (2001)
  • Gonyosoma oxycephalum, Merel J. Cox et al. (1998)
  • Gonyosoma oxycephalum, Ulrich Manthey & Wolfgang Grossmann (1997)
  • Elaphe oxycephala, Klaus-Dieter Schulz (1996)
  • Gonyosoma oxycephalum, Ludwig Trutnau (1986)

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)


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Gonyosoma oxycephalum
Gonyosoma oxycephalum
Gonyosoma oxycephalum
Red-tailed green ratsnake
Gonyosoma oxycephalum (close-up)
Gonyosoma oxycephalum (tail)
Gonyosoma oxycephalum

Range Map

Distribution map of Red-tailed tree snake, Gonyosoma oxycephalum in Thailand
  • Bang Lang National Park
  • Chae Son National Park
  • Chana District, Songkhla
  • Chiang Khan District, Loei
  • Chulabhorn District, Nakhon Si Thammarat
  • Doi Inthanon National Park
  • Doi Suthep - Pui National Park
  • Erawan National Park
  • Huai Kha Khaeng Wildlife Sanctuary
  • Huai Yang Waterfall National Park
  • Huai Yot District, Trang
  • Kaeng Krachan National Park
  • Kapoe District, Ranong
  • Kathu District, Phuket
  • Khao Chong
  • Khao Khitchakut National Park
  • Khao Nam Khang National Park
  • Khao Phanom Bencha National Park
  • Khao Phra - Bang Khram Wildlife Sanctuary
  • Khao Sok National Park
  • Khao Yai National Park
  • Khlong Saeng Wildlife Sanctuary
  • Khlung District, Chanthaburi
  • Ko Chang District, Trat
  • Ko Chang National Park
  • Ko Lanta District, Krabi
  • Ko Samui District, Surat Thani
  • Kra Buri District, Ranong
  • Kui Buri National Park
  • Lam Thap District, Krabi
  • Mae On District, Chiang Mai
  • Mae Rim District, Chiang Mai
  • Mae Sariang District, Mae Hong Son
  • Mae Takhrai National Park
  • Mueang Chiang Mai District, Chiang Mai
  • Mueang Chumphon District, Chumphon
  • Mueang Krabi District, Krabi
  • Mueang Nakhon Si Thammarat District, Nakhon Si Thammarat
  • Mueang Pan District, Lampang
  • Mueang Phuket District, Phuket
  • Nam Nao National Park
  • Nong Phok District, Roi Et
  • Nopphitam District, Nakhon Si Thammarat
  • Phrasaeng District, Surat Thani
  • Phu Kradueng National Park
  • Phu Luang Wildlife Sanctuary
  • Phuket Province
  • Pong Nam Ron District, Chanthaburi
  • Ramkhamhaeng National Park
  • Sadao District, Songkhla
  • Sai Yok District, Kanchanaburi
  • Sai Yok National Park
  • Sakaerat Environmental Research Station
  • Samoeng District, Chiang Mai
  • Si Banphot District, Phatthalung
  • Su-ngai Kolok District, Narathiwat
  • Takua Pa District, Phang Nga
  • Tha Chana District, Surat Thani
  • Tha Mai District, Chanthaburi
  • Tha Sae District, Chumphon
  • Tha Song Yang District, Tak
  • Thalang District, Phuket
  • Thale Ban National Park
  • Thong Pha Phum District, Kanchanaburi
  • Thung Song District, Nakhon Si Thammarat
  • Thung Wa District, Satun
  • Thung Yai Naresuan Wildlife Sanctuary
  • Umphang Wildlife Sanctuary
  • Waeng District, Narathiwat
  • Wang Nuea District, Lampang
  • Wang Wiset District, Trang
  • Yan Ta Khao District, Trang
Range map of Gonyosoma oxycephalum in Thailand