Poisonous snakes : Cobra, Krait, Vipers, Sea Snakes and Poison Apparatus of a Snake
Indian poisonous snakes are the cobras, the kraits, the vipers and the sea snakes. These can be distinguisted from the non poisonous by the tail, the arrangement and size of scales, plates and shields found over the body.
The vipers have movable upper jaw, so that the fangs when not in use can be folded backwards. It gets erected with the opening of the mouth while inflict-ing injury. It produces a loud hissing sound by expelling air through nostrils.
Pitless Viper - Vipera russellir (Russell's viper) Echis carinata (The little Indian viper).
Pit viper - Trimeresurus sp
Eg. Hydrophis sp Enhydrina sp
The poisonous snake possesses a poison apparatus comprising of a pair of poison glands, a pair of poison ducts and a pair of fangs. The poison glands are situated on either side of the upper jaw below and behind eyes. They are specialized salivary glands. A duct carries the venom secreted from each gland to the fang. A fang is meant for injecting the venom into the body of the prey. Fangs are specialized teeth of the upper jaw which are tubular or grooved.
Cobra is not an aggressive snake. When disturbed, it attempts to escape. When the snake attacks, the mouth opens by lowering the lower jaw. This makes the fangs to be erect to penetrate the muscles of the victim. When the mouth is closed the poison glands are pressed. The venom thus reaches the fangs and is injected into the body of the victim. This whole process takes place in no time.
There are two types of snake venoms. One type acts mainly on the nervous system (neurotoxic). It affects the optic nerves (causing blindness) or the phrenic nerve of the diaphragm (causing paralysis of respiration). The other type is haemolytic. It breaks down the red blood corpuscles and blood vessels and produces extensive extravasation of blood into the tissue spaces.
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