Thursday, July 3, 2014

General Identification of Snakes of Nepal

Snakes are the most feared animals in the world. Ophiophobia has to be to the topmost Phobia’s related to animals, followed by Arachnophobia (Fear of Spiders).  There are about 3000 Species of Snakes found in world, of with around 375 Species are venomous. In case of Nepal, we have around 89 Species of Snakes, of which 21 are venomous and little less than 7-8 species which can be very lethal. Snakes are common all over Nepal, even in the lower Himalayas, and there’s a data of Himalayan Pit Viper recorded from around 4200 meters. Personally, I found Collared Black Headed Snake (Sibynophis collaris) on my way to Langtang valley at around 3000 meters. Around 20000 bite victims are reported every year from Nepal, with 1000 fatalities.

Identification of snakes based on Photographs is pretty hard, without handling a snake  proper identification is a tedious job. The Snakes are identified on the basis of the structure and arrangement of Scales. Mostly the scales retain their characters throughout their life, but the color may vary.  To identify snakes, structure, position, number and arrangement of scales are generally considered.
The most used scales are, Scales of head, upper and lower labial (Structure, position, arrangement and number), scales of dorsal side, scales of ventral, both ventral and subcaudals.

How to distinguish Venomous snakes from Non Venomous:
1) The first method for identifying a snake can be by opening its mouth, if there are two fangs on the upper front region of premaxilla, if the fangs are present, the snake is definitely venomous.
2) Sometimes the fangs may be broken, and appear to be absent. In this case, other attributes of the snake must/may be observed.
3) Examine the dorsal and ventral scales on the body
If the scales are smaller, slightly rounded, imbricate and scales on the dorsal and ventral surface are exactly similar then the snake is no Venomous.
If the ventral scales are narrow and don’t cover the belly, then the Snakes aren’t venomous.
If the ventral scales run along the belly and are large, then the snakes can be venomous or non-venomous
4) Examine the head and scales on the head
 • If the head is broad flat and triangular and numerous small scales are irregularly arranged the head then the   Snake is venomous.  (If the head is triangular, it’s the Vipers, and highly venomous)
If the snake has a similar structure of head as mentioned above along with a pit, called a Loreal pit, between its eyes and the nostril, the snake is a Pit Viper
If the snake has an elongated or rounded head or blunt, apart from triangular, it might be venomous as well as non-venomous.

5) Examine the overall body of the snake
If the snake has hood shape mark on its head, dorsal scales rhombiod space in between them, and if the third supra-labial shield touches the eye and the nostrils then the snake is venomous (Cobras). And if the snake with similar structure has an Occipital shield then the snake is King cobra.
If the central rows of scales are larger than the surrounding scales and vertebral hexagonal scales are present then the snake is definitely venomous (Kraits). They also have a metallic shine on the body.

Rest of the snakes, without above mentioned characteristics are mostly rare fanged and not fatal to humans.  There are 5 families of snakes found in Nepal,  Typhlopoidea,  Pythonidae,  Colubridae,  Viperidae, Elapidae. Of which Viperidae (Vipers)  and Elapidae (Cobra’s and Kraits) are extremely dangerous. While most of the Colubrids are non-venomous while few can be venomous but not lethal.

So basically in case of Nepal, there’s no reason to kill a snake at sight! Most of the snakes are non-venomous.  One can easily recognize a cobra, krait and vipers, just avoid those snakes and you all should be fine, apart from that, there’s no need to worry!

Here's a photo chart of Snakes Identification, described above



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