re: slit vs round pupils - This is only mostly true, and then only in North America. Most venomous snakes here have vertical slits for pupils. However, the coral snake (very venomous) does not.
In the USA t’s easier to just learn to identify the four kinds of venomous snakes: rattlesnakes (easy), coral snakes (even easier) copperhead (pretty easy) and water moccasin (hardest, but still pretty easy.)
To start with, all except the coral snake (which is gaudily colored red, black, and yellow) have bodies that are quite thick for their length, and triangular heads.
There are variations within a group - for instance, there are several kinds of rattlesnakes, but you can easily tell they are all rattlesnakes.
re: slit vs round pupils - This is only mostly true, and then only in North America. Most venomous snakes here have vertical slits for pupils. However, the coral snake (very venomous) does not. In the USA t’s easier to just learn to identify the four kinds of venomous snakes: rattlesnakes (easy), coral snakes (even easier) copperhead (pretty easy) and water moccasin (hardest, but still pretty easy.) To start with, all except the coral snake (which is gaudily colored red, black, and yellow) have bodies that are quite thick for their length, and triangular heads. There are variations within a group - for instance, there are several kinds of rattlesnakes, but you can easily tell they are all rattlesnakes.