Snakes - how do you know if it is poisonous

Nonvenomous snakes usually have a round pupil in the eye. I wouldn't suggest this way to find out because it is very hard to tell if they do. Nonvenomous snakes have only one color most of the time. This is only most of the time so if you see a snake that is one color don't go running up to it! Just check for the other ways you can tell. If the snake has stripes all the way from head to tail it's probablly a nonvenomous snake. This is only if the snake you are looking at has stripes. Also nonvenomous snakes have a spoon-shaped round head. Venomous snakes have an eliptical pupil like a cats eye. It looks like a small slit in the middle of the eye. If they have a rattle on their tail, it is a venomous snake because all snakes that have rattles are rattlesnakes of course. All rattlesnakes are venomous! Some non-venomous snakes rattle their tails though, but have tails that come to a tip, and do not have the rattle "buttons" on them that sound like little salt shakers. They also will have an arrow-shaped or triangular wide head if they're venomous. A venomous snake also will have a small depression in between the eye and their nostril. This is called a pit which is used to sense heat in their prey.

you just have to know your snakes. Its somthing you have to know and if you dont call someone who does.

the snakes head is how you can tell if it looks like the spade in the deck of cards it is poisonious if not tjen its not a viper

well you can consult the internet and know what type of snakes live in the region you are living in so you are not clueless about wat snake you could have seen.