Generally it's the medical organization research which acknowledge the toxicity of a species of snakes,and it's usually acknowledged by herpetologists of the world.
Historically the Big Four venomous species refereed in india are
1. - Indian Spectacled Cobra
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2. - Saw Scaled viper
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3. - Russel's viper
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4. - Common indian Crait
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The official journal published by Wilderness Medical society (PMID: 18715121) questions on the big four venomous species classification of snakes in india and reffering to Levantine Viper (Macrovipera lebetina) causing Envenoming and the Indian polyvalent anti–snake venom being non effective against this snake bite, only option leaving is to import the antivenom. this study clearly indicates on the moving of big four to big five. !
Levantine Viper (Macrovipera lebetina) or commonly known as "Gunas" generally found in Northern parts of india in Kashmir, in rocky mountain areas also known as "Mountain Adder". An earlier published article by Wilderness Medical society (PMID: 17447706) again questions on the big four now referring to a recent discovery that another species, the hump-nosed pit viper (Hypnale hypnale), is fatal and highly venomous with the Indian polyvalent anti–snake venom being non effective both these articles were coauthored by a very well known researcher Dr. Ian D. Simpson.
The Snake Research unit of Little Flower Hospital and Research Centre in kerala, had clearly identified the study of bites by hump nosed pit viperand published on their webpage of their findings...click here the Hump-nosed Pit viper ( Hypnale hypnale ) or commonly called as "churutta" is predominant in western ghats. WHO-South east asia published and circulated the posture "The big 5 venomous snakes of south india" as shown in the image,
So is it big five ? if yes which species Hump-nosed pit viper or Levantine viper ??
or both make it into a BIG SIX !!!
Or is it that the Dr. Ian D. Simpson. changed his mind after the visit to SRU @ Little Flower Hospital on knowing about Hump nose research.. ?? Or we just continue to Big five based on the latest report of Dr. Ian D. Simpson & WHO
or Just historical big four ?
there's nothing heard still from the Herpetologists ?