Cottonmouths have a rank odor to them for sure. I can't descibe it, but I know it when I smell it. I usually smell one before I see it. We used to find them around our yard and garden, but there is no water source, except a couple of small ponds that are within a half mile. We would call them high land moccasins. Our cocker spaniel mix killed every one she found and never got bit. I agee with some that the snake in the OP doesn't look like a moccasin to me, and it's way too big. I get a kick out of messing with those who are absurdly scared of them, but not with a real snake. I know the dangerous ones and have no problem killing them, but I'll leave most others alone or pick them up and move them. I don't like any non-native species, plant or animal. You can have your boas and pythons, if it gets loose and I see it, it's history.