I've spent my entire life fascinated with snakes. When I was young, my cousin and I were snake hunting . We caught about a dozen or so. Mostly garters and a few milk snakes. One garter had red bands instead of the traditional gold bands. Any way, in regard to venom, all "non-venomous" snakes have saliva that is an irritant to human skin. In most cases it is harmless and not even noticeable, depending on how sensitive a person can be to it. The bigger the snake, the more saliva thus, the more irritant. I've been bitten by various snakes, including a python. The worst I've gotten is a red painless inflammation for day or two. Snakes are good for the environment, even poisonous one. Venom is used more for catching prey and occasionally defense. It is never used to aggressively attack a non-prey such as a human. A rattle snake will do everything in it's power to warn you about it's presence, Hence the rattle. It doesn't use it's rattle when hunting.