How to identify Venomous and Non-Venomous Snakes? Snake Identification based on the Tail, Ventral scales, nature of the Head, Vertebral scales and Jaw scales.

Snakes are extremely well- adapted to a wide variety of habitats namely aquatic, fossorial, arboreal, and terrestrial. The variation of their sizes, shapes, and colors is generally due to the adaptive radiation in a mode of life. Snakes are intrinsically fascinating and form an important component of the biota. Naturally, their curious mode of propulsion, venom, and constricting mechanism have made them an important group of predators, and the interactions maintain a natural balance in almost every ecosystem.

About 3500 species of snakes are recorded on earth inhabiting both land and sea, of which about 375 are venomous. Snakes are abundant all over the world except in the Arctics, New Zealand, and Ireland. It is postulated that there are about 3000 species of terrestrial snakes in the world and they are predominant in the warm climates and lush green regions of the tropics. About 278 species are found in India out of which 58 species are venomous. The snakes are objects of fascination for studies since time immemorial. The body of a snake is often modified to suit its ecological conditions

Fifteen families are currently recognized, comprising 456 genera and over 2,900 terrestrial species. They range in size from the tiny, 10 cm long thread snake to pythons and anacondas of up to 7.6 meters (25 ft) in length.

But, why is basic snake identification skills important?

Increasing industrialization and urbanization have led to habitat loss of these reptiles. Presently many snakes have made their appearance in and around areas with proximity to the human population due to loss of habitats and environmental stress. During such conflicts, people with lesser knowledge about snakes tend to harm or kill the animal for protecting themselves. Many times, non-venomous species are mistaken as venomous ones and are killed. Therefore, basic knowledge of snake identification is required if your residential area also has snake inhabitants. Whenever you spot a snake in your vicinity do not handle it on your own unless you are experienced in snake rescuing. You can either contact a local snake rescuer or an animal rescue NGO if you spot a snake in your residential vicinity.

Snake Identification: (You can use shredded snakeskin and not a live snake for safety purpose)

Starting with the tail:

1) When the tail is Flat and laterally compressed the snake is considered to be venomous for example sea snakes. The majority of sea snakes are highly venomous and all of them have flattened tails.

 Yellow-Bellied Sea Snake (Hydrophis platurus)

2) When the tail is cylindrical and blunt like that of sand boas, then that snake is non-venomous.

Red Sand Boa (Eryx johnii)

3)When the tail is cylindrical and round like that of Terrestrial or land snakes, they can either be venomous or non-venomous

So, the snakes which have cylindrical and round tail they are classified into two categories based on scales on their belly i.e., ventral scales.

A. If the Snake has small scales on the belly and back region like that of Buff Striped Keelback, then it is non-venomous.

 Buff Striped Keelback (Amphiesma stolatum)

Small scales on the belly

B. Those having narrow belly scales like Sand Boa are considered to be non-venomous.

Narrow ventral scales

C. While the snakes having broad belly scales and cover the entire girth of the belly region,

Broad ventral scales

 are further classified into three categories based on the nature of the head:

a) If the scales on the head are small and no pits are visible then the snake is considered to be venomous for example Saw-Scaled Viper (Echis carinatus) and Russell’s Viper (Daboia russelii)

Saw-Scaled Viper (Echis carinatus) head

b) If there is a loreal pit between nostril and eye along with small scales on the head, then the snake is considered venomous. For example, Pit Vipers.

Bamboo Pit Viper (Trimeresurus gramineus)

c) When the snakes have Shields on their head, 

they are further classified into three more categories based on the vertebral scales and jaw scales:

i) When the vertebral scales are not large, the third supra labial shield (upper jaw) is large touching the nostril and eye then the snake is venomous for example cobras and Coral snake

ii) If the Vertebral scales (mid-dorsal on back) are large and hexagonal, four infra labial scales with 4th one largest then the snake is venomous for example Common Krait (Bungarus caeruleus)

Common Krait (Bungarus caeruleus) infralabial scales

iii) The last category is where none of the prior mentioned features are seen, they are non-venomous. E.g., Indian Rat snake (Ptyas mucosa).

Indian Rat snake (Ptyas mucosa)

I am organizing a quiz on Snake Identification of species endemic to India on the 29th of May link will be made available through the Instagram handle whose link is in the description.

Visit my Instagram handle to see different snake identification and detailed posts on snakes.

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