Snake poison and identification of poisonous and non poisonous snakes

Common poisonous snakes of India are cobras, kraits, vipers, sea snakes and coral snakes. All poisonous snakes have poison gland which are modified superior labial or parotid salivary glands. The poison injection fangs (teeth) are maxillary teeth located on maxilla of skull. 

Snake poison is a mixture of enzymes and specific toxins ,ions and is a good digestive juice. It is fatal only when mixed in human blood. There are three categories of snake venoms or toxins, neurotoxic and haemotoxic venum. The poisons of cobra, krait and sea snakes are neurotoxic. Neurotoxic poison badly affect nervous system and  cause death by paralysis of respiratory muscles and asphyxiation. Haemotoxins are typical of vipers and badly affects blood vascular ystem. They cause tissue destruction and widespread hemorrhage of organs. Proteolysin is present in the venom of viper and  affects circulatory system. Myotonic poison badly affects muscular system.The best medicine of treat snake venum is a antivenin or antivenom serum which contain antibodies. Different types of antivenins are required against different snakes due to differences in the qualities of their venoms. Eg.Benadryl and antisera They are used to check or counteract the effect of haemotoxins. An antivenin is prepared by injecting a horse with gradually increasing the doses of a snake venom until the horse becomes fully immunized . Blood serum of horse is then collected and preserved. In India, antivenin injections are prepared at Hafkin's institute, Mumbai and Central Research Institute, Kausauli (Simla). Sea snakes are poisonous; Two common sea snakes are Hydrophis and Enhydrina.All sea snakes have large flattened scales on the head and the tails are flattened laterally, they are all poisonous except one species.

In snakes scales, plates and shields, their arrangement and size shows high degree of variation and they help in the identification of poisonous and nonpoisonous snakes. The common characteristic features of both the types are:

1. Turn to the underside (ventral) of the snake and observe the scale pattern. If the scales are small and uniform the snake is non-poisonous.If the scales are transversely long but some of the rows of small scales of the back are visible on the underside, it is non-poisonous.
2. If the scale pattern on the underside shows transversely arranged plates and no small scales of the back reach the underside, them it may be poisonous or non-poisonous. To decide whether poisonous or non-poisonous, look at the scale pattern on the top of the head; if itcovered with small scales, it is one of the deadly poisonous snakes like  a viper.
3. But if the scales on the head are in the form of large shields or plates, it may be non-poisonous or one of these poisonous snakes: a pit-viper, a cobra, king cobra, a coral snake. To decide look at the side of the face.
1. If it is a pit larger than the nostril is present between the nostril and the eye, it is a pit-viper.
2. If no pit is present but the third upper labial (supralabial) scale touches the nasal scale and the eye, it is a cobra, king cobra or a coral snake, Naja naja (cobra).
3. If none of the two above characters is present, then look for the following two characters:
1. Whether the middle row of scales on the back enlarged and
2. When the fourth scale on the lower lip (infralabial) along the margin of the lower jaw is the largest, then it is a krait.
4. If (i), (ii) and (iii) characters are absent, then its non-poisonous.