Well...you don't have to really breathe on it...just blowing towards it is fine. The scent molecules will easily waft a meter or more, unless you're wearing a mask or have lung capacity issues. It's kind of like this, just less directed and powerful:My concern would be more about proximity. If I am close enough to breathe on a snake, I am close enough to get bit. Non venomous I wouldn't be too scared of, but thoughts of laying down close enough to a rattlesnake...I think I'd stay a little farther away.