I've been running around swamps all my life here in eastern N.C. and we have eastern diamond backs,copper heads[rattle snack pilots as the old folks call them], and cotton mouth moccasins.Cotton mouths eat carrion on occasion and the danger in there bite is more from infection.Copper heads can be agressive and will chase you.I have fished around cotton mouths sunning themselves on logs and stumps with out too many problems but they are curious and will come up to your boat and try to climb in. Jimmy