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Venomous Snake That's Not So Venomous - Mock Viper

Green Country Vol. 117 (Dec 2015)

To most people, vipers are fearsome creatures. We are taught when young age to identify the triangular head of vipers. Mock Viper (Psammodynastes pulverulentus) indeed has a triangular head, yet is not as venomous as it looks. Its venom is of low toxicity, and the snake is not known to actively attack people. There is no record of harm to human by the species to date in Hong Kong.

Hong Kong is home to as many as 86 native and naturalised species of reptiles: 20% of the total in China. Reptiles include snakes, turtles and lizards. In Hong Kong, snakes account for the majority of reptiles, with 52 species, 14 of which are native terrestrial venomous snakes, including Mock Viper.

Mock Viper, or “brown mountain snake” in Chinese, is active in woodland, shrubland, and grassland. The small snake is 40-60 centimetres in length and covered with many black spots on the dark brown body. Its head is triangular, with a conspicuous spear patch. Apart from Hong Kong, the species ranges across India, Indonesia, Malaysia and southern China. It is an uncommon species in Hong Kong and can only be found on Lantau, and in the east New Territories and Tai Po Kau Nature Reserve.

Less than fatal

Mock Viper is more active during daytime and feeds on small animals such as frogs, geckos and skinks. It is often mistaken for a highly venomous viper due to its aggressiveness and the triangular head. It even earned the common name Mock Viper. Although venomous, the snake's fangs are not at the front of the mouth but at the back. In the unfortunate case of an accidental bite, the low toxicity is not fatal. It will at worst cause a swollen wound, pain and bleeding.

Egg-laying or live birth?

Snakes are oviparous, which means that after mating eggs are laid and baby snakes will hatch. For some species, however, reproduction is ovoviviparous, that is, the fertilised egg will hatch inside the mother’s body and the mother will give birth to the baby snake when it is mature.

Ovoviviparous babies are born directly by the mother, which seems like a life birth. But the two are indeed different. The embryo of the latter absorbs nutrients directly from the mother; but the former only absorbs nutrients from the egg. Mock Viper is one of the ovoviviparous types. Compared to oviparous species, the ovoviviparous has a higher rate of survival due to the protection of the mother against predation.

Text︱Linda Yip


Mock Viper preying on Long-tailed Skink (Eutropis longicaudata)
Mock Viper has a triangular head with a conspicuous spear-shape pattern on top.
Mock Viper is ovoviviparous - giving birth to baby snakes.