So, this takes a bit of common sense guessing provided you know a little background--there are 37 different venomous snakes found in Viet Nam. When you think about how snakes live and how most army platoons were essentially walking through the wilderness, chances are very high that they encountered venomous snakes fairly often. As one GI explains, "The Army didn't tell us how to tell "good" snakes from "bad" snakes..." ( (ichiban1.org/html/stories/story_38.htm) According to the Straight Dope, only aobut 25-50 actual snake bites were reported annually during the war, but that doesn't mean that they weren't encountering snakes on a daily basis.