Snakes:

Snake are cold blooded, elongated legless carnivorous reptiles that are in majority perceived as deadly to humans. Snakes can live just anywhere but they do need warm temperature. They are cold blooded so they lack the ability to regulate their body temperature.

There are many interesting facts about snake like they have no legs, no eyelids but most species have transparent scale which is known as brille. The jaw bones are very loose which can be disconnected at the time of swallowing. Their skin is very elastic which helps them to stretch their mouth. The Head of different snakes varies in shape and some of the snake have additional organ in their head know as heat pit which is used to detect the heat.

The vision and hearing sense of snakes are very poor and that is why they are gifted from few other senses. They use their tongue to pick up scent particle from the air and then the mouth organ’s enhances the smell.

Snakes have interesting defensive behaviour like some of them are well camouflaged like tree snakes may be green or brown while desert snake may be yellow or light brown which helps them to confuse their predator.

Snakes can be venomous or non-venomous. Venomous snakes have venom glands and modified teeth’s and fangs for the injection of venom to attack their enemies. These snakes are equipped with enough venom to kill a human in course of hours. Whereas Non-venomous snakes constrict their prey. Non-venomous snake throw couple of coils to their prey and begins to squeeze. Eventually the prey will not be able to inhale and will be dead very soon.

Spectacled Cobra:

A highly poisonous snake, spectacled cobra is also known by its scientific name "Naja Naja" and belongs to elapidae family. Cobra stands out to be one of most valued and highly worshipped snake in the world. They are mostly found in rain forest and open fields, throughout India and parts of Asia. They feed on rats, rodents, frogs, toads and other snake for its survival. An adult cobra shed its skin six times a year. Cobras are active during both day and night.

Feature Description: Spectacled cobra as the name describes, is known for its attractive and distinctive hood marking which looks like spectacles. When threatened, they raise their body and spread the neck region to form the hood. The typical length of spectacled cobra is 1.8 to 2.4 metres. It has small nostril placed between 2 nasal scales and small eye with rounded pupil.

Scalation Description: The head scales of spectacled cobra includes rostral, 2 internasal, 2 prefrontals, 1 frontal, 2 supraocular, 2 parietals and small occipitals. They have generally 1-7 supralabial scales, 1 preocular and 3 postocular. There is no loreal scale present which makes them different from snakes of viperidae family. The body scale is smooth and rounded.

King Cobra:

King cobra, the world’s longest venomous snake, is known for its menacing looks and deadly bites. King cobra and spectacled cobra share same family i.e. elapidae but
belong to two different genus. The scientific name of king cobra "Ophiophagus Hannah" is a Greek derived word which means “snake eater”. They feed mainly on other snakes including the venomous snakes, but will also eat lizards, rats, frogs and sometimes small mammals. King Cobra’s most common meal is rat snake, and the search of this species brings them close to human settlements. King cobras live mainly in dense rain forest, nearby to lakes and streams. The unique nature of King cobra is that they are the only snake in the world that make nest for their eggs using hays, leaves and guard them violently until they are hatched.

When threatened, they flare out their hood just like spectacled cobra and can also raise one-third of their body off the ground, still can move forward and attack its prey which makes them more dangerous. The venom of King cobras are not the most powerful, but the amount of venom they can inject in single bite is much higher, which can kill 20 people or an elephant.

Feature Description: The typical length of king cobra averages at 3 to 4 metres but it is known to grow upto 5.5m making them the longest of all venomous snake. One of the main features which distinguish king cobra is that it does not contain spectacled mark on backside of its hood as present in spectacled cobra. The body color is usually olive green, tan or black which contains pale yellow bands down the length of the body. It has small nostril and round pupil.

Scalation Description: Like spectacled cobra, king cobra also have rostral,2 internasal, 2 prefrontal, 1 frontal, 2 supraocular, 2 parietals, 1-7 supralabial scales, 1 preocular and 2 postocular. But the major difference in the scalation of both the snake is the size of occipital. King cobra has bigger occipital scales. The dorsal scale is smooth and the ventral scale has thick black bands which makes it different from spectacled cobra.

Common Krait:

Common krait i.e. "Bungarus caeruleus" belongs to elapidae family and is a species of genus bungarus. It is also known as Indian krait or blue krait. Like all krait species, common krait is nocturnal species. It remains sluggish and docile during day time and becomes more active and alert at night. Common krait is mostly found near to human settlements, inside or outside house. It can also be found in fields, low scrub jungles, rat holes, termite mounds, water etc. Common krait feed all kinds of snakes, including species of krait and cobra. These snakes also eat lizards, frogs, rats and mice.

Feature Description: The body color is black with shiny smooth scales. Presence of milky white band is the main visible and notable feature of common krait used for identification. Common krait has flat head and the body is cylindrical. The tail is small and rounded. The eyes are small with round black pupil which sometimes makes it indistinguishable from its body.

Scalation Description: Common krait has all the head scales like spectacled cobra and king cobra, but it has only 2 postocular which is 3 for other two. The vertebral scale is considerably big and hexagonal in shape.

Russell's Viper:

Russell's viper, also called as daboia, is highly poisonous snake of viperidae family. The scientific name of russell's viper is "daboia rusellii". The meaning of “daboia” is “that lies hid”. Russell’s viper is one of the species responsible for most of the snake bite incidents and death due to its wide distribution and frequent occurrence. They are mostly found in open fields, forest and near human settlements. Russell's viper is considered to be responsible for most of the snake bites because of its wide distribution and frequent sitings near the human habitat.

Feature Description: Russell's viper can grow upto 1-1.5 metres in length. The head is large, triangular in shape and distinguishable from neck, with big nostrils which lies in middle of single large nasal scale. The head also contain a 'V' mark and two triangular dark marks on both sides of temples. They have big eye with vertical pupil. The body has a dry appearance and contains consecutive dark brown oval spots which is bordered by black colour and again surrounded by light yellow or white colour. Dark triangular patches below the eyes are noticable in russell's viper.

Scalation Description:Head scales of snakes of viperidae family are small as compared to those of elapidae family. Internasal, prefrontal, frontal, parietal are present, but in smaller size. Supraocular scales are present above both the eyes. They have 10-12 supralabial scales, preocular and postocular scale. loreal and subocular scales are present in snakes of viperidae family but absent in elapidae, which helps in determining the snake. Nose is situated between cresent shaped supranasal and nasorostral scale. Dorsal scale of russell's viper is keeled.

Saw Scaled Viper:

Saw scaled viper, also known as “Echis carinatus" is another snake of viperidae family. It is the smallest member of the "Big Four" snakes. Though it is a small snake, but it is considered to be very dangerous because of its irritable and aggressive nature. They are generally nocturnal, but sometimes also active during day time. They can be found in different places such as rural settlements, fields, deserts, rocks etc. It normally feed on rodents, large insects, toads and scorpions. When threatened they will move slowly in with the body looped into ‘S’ shape.

Feature Description: They are typically 20-60 cm in length, but can grow upto 80 cm. They have dry appearance like russell's viper. Head is broader and distinct from neck and has small nostril. The eyes are very big with verticall pupil. Plus '+' mark is noticable in the head of saw scaled viper which makes it different from russell's viper.

Scalation Description: Saw scaled viper contains small keeled head scales. Nostril is surrounded by 3 nasal scales. Eye is surrounded by preoculars, postoculars and 3-4 rows of subocular scales. 3-4 loreal scales are present between the eye and the nose. dorsal scale is strongly keeled.

Hump Nosed Pit Viper:

Hump Nosed Pit Viper also known as “Hypnale hypnale”, are venomous pit viper species which belongs to viperidae family and are mostly found in India and Sri Lanka. Pit Vipers are well-known for their ability to sense heat through pits located between eyes and nostrils on both the sides.

Feature Description: They are small snakes with an average length of 30-45cm. They have typical triangular head which is broader than the neck. Eyes are big with elliptical pupil while nostril is small. Snout is upward and pointed. Body contains grey and black spots. Pit present between eyes and nose makes pit vipers different from other snakes of same family.

Scalation Description: Head scales of hump nosed pit viper are bigger than the one in Russell’s viper and Saw Scaled Viper. Scales on snout are small and irregular while frontal, supraocular and parietals are large. They have 1 nasal, 2 preocular, 2-4 postocular, 1 loreal and 7-9 supralabial scales. Dorsal scales are weakly keeled.

Table 1: Classification of the taxonomy features based on the observer view

Feature Table
Top / F1
F2
F3
F4
F5
F6
F7
F8
F9
F10
F11
F12 / Rostral
Internasal
Prefrontal
Supraocular
Frontal
Parietal
V mark on head
Triangular Head
Dark patches on both sides of head
Number of scales between supraocular
Big Occipital
Plus sign in the head
Side / F13
F14
F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
F38 / Small nostril
Round pupil
Big nostril
Elliptical pupil
Loreal
Nasorostral
Supranasal
Triangular brown streaks behind or below eyes
Subocular
Nasal
Preocular
Postocular
Number of Supralabial scales
Pit between the eyes and nostril
Bottom / F26
F27
F28 / Mental
Asterior Sublingual
Posterior Sublingual
Body / F29
F30
F31
F32
F33
F34
F35
F36
F37 / Round Dorsal scale
Hood
Spectacled mark on hood
Keeled Dorsal scale
Spots on Dorsal scale
White/yellow strips on Dorsal scale
Black strips on ventral scale
Enlarged and hexagonal vertibral scale
Ventral scale
Table 2: Description of feature values assigned in the database.
Values Assigned / Description
0
1
2
2-4
6-9
7,8, 10 or 11 / Absent or Invisible in the image
Present, but in small or narrow size
Present, but in big or broad size
Count value of certain scales
Number of scales between supraocular scales
Number of Supralabial scales