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Identification of poisonous and non-poisonous snakes

Scales, plates and shields, their arrangement and size help in the identification of poisonous and nonpoisonous snakes

Zoology [Science]

Central Board of Secondary Education [12]

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Scales, plates and shields, their arrangement and size help in the identification of poisonous and nonpoisonous snakes. The common characteristics of both the types are:

  1. Turn to the underside (ventral) of the snake and see the scale pattern. If the scales are small and uniform, or 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 arranges plates and no small scales of the back reach the underside, them it may be poisonous or non-poisonous. To decide, look at the scale pattern on the top of the head; if it is covered with small scales, it is one of the deadly poisonous snakes such as 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 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. the middle row of scales on the back enlarged and
      2. 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.

  4. All sea snakes have large flattened scales on the head and the tails are flattened laterally, they are all poisonous except one species.

    Identification of poisonous and non-poisonous snakes
    Structures Characters Nature Snakes
    1. Tail (a) Tail laterally compressed, oar-like Poisonous Hydrophis, Enhydrina Sea snakes
    (b) Tail cylindrical, tapering Poisonous and non-poisonous Examine further Land Snake
    2. Belly scales or ventrals (a) Belly scales small, continuous with dorsals Non-poisonous
    (b) Ventrals not fully broad to cover belly Non-poisonous Pythons
    (c) Ventrals broad, fully covering belly Examine further
    3. Head scales, sub-caudals (a) Head scales small, head triangular. No loreal pit
    1. loreal pit
    2. subcaudals single
    Poisonous

    Poisonous
    Poisonous
    Pitless vipers

    Vipera russelli
    Echis carinata
    (b) Head scales small. A loreal pit present between nostril and eye Poisonous Pit vipers
    (c) Head with large shields. No loreal pt Examine further
    4. Vertebrals, 4th infra-labial 3rd supra-labial (a) Vertebrals enlarged, hexagonal 4th infra-labial largest Poisonous Krait, Bungaurus
    (b) Vertebrals not enlarged, 3rd supra-labial touches eye and nostril
    1. Neck with a hood and spectacle mark
    2. Hood absent. Coral spots on belly
    Poisonous

    Poisonous
    Poisonous


    Cobra, Naja
    Coral snakes
    (c) No such characters Non-poisonous

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Related Words:

Poisonous Snake, Non-poisonous Snakes, Viper, Nostril, Pit-viper, Cobra, King Cobra, Coral Snake, Infralabial, Identification Of Poisonous And Non-poisonous Snakes, Hydrophis, Enhydrina, Sea Snakes, Land Snake, Pythons, Pitless Vipers, Vipera Russelli, Bungaurus, Ventrals, 4th Infra-labial

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