| Features | Poisonous Snakes | Non-Poisonous Snakes |
|---|---|---|
| Habits | Usually Nocturnal | Not So |
| Tail | Compressed | Not much compressed |
| Teeth | Two long fangs | Several small teeth |
| Fangs | Hollow like hypodermic needle | Short and solid |
| Belly Scales | Large and cover entire breadth | Small and do not cover entire breadth |
| Head Scales | Small (vipers) If Large additional features present a)pit or opening between eye and nostril(pit viper) b)3rd labial touches eye and nasal shields(cobra or coral snakes) c) Above two feature absent but central row of scales on the back enlarged and only four infralabial scales on undersurface of mouth , and fourth infralabial is largest (krait) | Large without additional features |