Ancistrodon : Pit Viper


PHYLUM :- CHORDATA (Notochord, dorsal tubular nerve cord present and gill slits present )

Group :- CRANIATA ( Definite head. Cranium with brain present )

Sub-phylum :- VERTEBRATA ( vertebral column present)

Division :- GNATHOSTOMATA ( Jaws and paired appendages present )

Super class :-  TETRAPODA ( Paired limbs, lungs, bony skeleton and cornified skin)

Class :- REPTILIA ( Scaly vertebrates with right and left aortic arches. Single condyle, pulmonary respiration. Embryo with amnion and allantois ).

Sub-class :- DIAPSIDA ( Skull with two temporal openings separated by postorbital and squamosal ).

Order :- SQUAMATA ( Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse).

Sub-order :- OPHIDIA ( Snakes. Limbs, feet, ear openings sternum and urinary bladder absent. Mandibles jointed anteriorly by ligament. Tongue slender, bifid and protrusible. Left lung reduced).

Family :- VIPERIDAE ( Tails compressed used for swimming ).

GENUS :- Ancistrodon


Pit viper Found in hilly region in north and eastern part India and Asia.


Pit Viper is viviparous. Habitats ranging from parched desert to rainforests. They may be either arboreal or terrestrial, and one species is even semiaquatic.


  • Commonly called as Himalayan pit viper.
  • Body is not much elongated, measures about 1 metre in length.
    Body divided into head, neck, trunk and tail.
  • a deep pit, or fossa, in the loreal area between the eye and the nostril on either side of the head. These loreal pits are the external openings to a pair of extremely sensitive infrared-detecting organs, which in effect give the snakes a sixth sense to help them find and perhaps even judge the size of the small, warm-blooded prey on which they feed
  • Colour is bluish brown with dark brown or black spots which appear
    like crossbars.
  • Head is triangular containing trunk nostrils, eyes and mouth. A
    characteristic loreal pit in present on each side of upper jaw separating
    with eye and nostril. Head shields are large.
  • Upper lip is slightly raised in rostral region, post-ocular two, supra-ocular enlarged sideways to form shield over the eye and pre-ocular three in number.
  • Eyes are big with golden iris and vertical pupil.
  • Among vipers, these snakes are also unique in that they have a specialized muscle, called the muscularis pterigoidius glandulae, between the venom gland and the head of the ectopterygoid.


Pit viper is a shy and alert snake. Even on slight disturbance it runs back to its shelter.
It is a poisonous snake having well-developed, erectile poisonous and sheathed fangs.


  • This snake contains large head shields and loreal pit and above features, hence it is Ancistrodon or Pit viper.

Ancistrodon : Pit Viper
Ancistrodon : Pit Viper


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