It's extremely difficult to tell if a snake is venomous or not, unless you know a ton of the different kinds and whether or not they are. A lot of the so called, "certanties" about how to tell if a snake is or not, have holes, like the eye slits, or the diamond head, or a rattling tail. Some snakes rattle their tales against leaves, etc...just to mimic venomous snakes. Some snakes also use bright colors to look like they are venomous, like the ringneck snakes, while Coral snakes are really bright, and venomous.