Thai National Parks

Species of Thailand

Viperine sea snake

Hydrophis viperinus, Philipp Schmidt, 1852

(In Thai: งูชายธงท้องขาว, ngu chay thong khao)

Viperine Sea Snake, Hydrophis viperinus, is a species of Elapidae (Hydrophiinae-sea snake) and Thalassophina viperina is its synonym. It is thought to be naturally rare but widespread. It is venomous.

Diagnostic Characters

Scales hexagonal, juxtaposed, in 27-34 rows on the neck, 37-50 at midbody; ventrals 226-274, anteriorly about half the width of the body, narrowing posterior to about twice the width of the adjacent scales, or slightly less; head shields entire, nostrils superior, nasal shields in contact with one another; prefrontals longer than broad, not in contact with upper labials; 1, rarely 2, pre- and 1-2 postoculars; 7-9 upper labials, 3-5 bordering eye (sometimes only 3-4 or 4-5); usually 1 anterior temporal, occasionally 2 or 3; body color, more or less bicolored, gray above, white below, the 2 usually clearly demarked on the sides, often with 25-35 dark rhomboidal spots, rarely with dark bands. Total length males 925 mm, females 820 mm; tail length males 100 mm, females 80 mm.


Northern coasts of the Indian Ocean and western Pacific: from the Persian Gulf to around India to Indonesia and southern China. IUCN lists the following countries: Bahrain, Bangladesh, Cambodia, China, India (Andaman Is., Nicobar Is.), Indonesia, Iran Iraq, Japan, Kuwait, Malaysia, Myanmar, Oman, Pakistan, Philippines, Qatar, Saudi Arabia, Singapore, Sri Lanka, Taiwan, Thailand, United Arab Emirates, and Vietnam.

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Scientific classification

Hydrophis viperinus

Common names

  • English: Viperine sea snake
  • Thai: งูชายธงท้องขาว, ngu chay thong khao


  • Thalassophina viperina, Van Stanley Bartholomew Wallach et al. (2014)
  • Hydrophis viperinus, Kate Laura Sanders et al. (2012)
  • Thalassophina viperina, Arne Redsted Rasmussen et al. (2011)
  • Praescutata viperina, Vladimir Emelyanovich Kharin (2005)
  • Thalassophis viperina, David et al. (2004)
  • Praescutata viperina, R. C. Sharma (2004)
  • Praescutata viperina, Khan (2002)
  • Praescutata viperina, Jeroen van der Kooij (2001)
  • Thalassophis viperinus, Wolfgang Grossmann & Frank Tillack (2001)
  • Praescutata viperina, Patrick David & Ivan Ineich (1999)

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)


No photo for this species yet

Range Map

Range map of Hydrophis viperinus in Thailand