I went golfing while on vacation in Panama city once. It rained for about an hour, then we got back out on the course. There was at least 1 cottonmouth on every fairway! I bet I saw 20 of them before we were finished. Some were close, too.
In KY we have copperheads and timber rattlers. They get very large here compared to the average size for each species. Copperheads are not so deadly, but I wouldn't want to get bitten. Timber Rattlers are more dangerous. My great uncle lost two fingers and part of his hand to one.
My dad works in the mines, so they always find them inside the stacks of timber waiting to be hauled inside. They cut their heads off and put them in each others lunch buckets, or curl them up where people have to crawl through fire doors.
In the early 80's they killed one that was 72 inches, very close to longest ever recorded at 74.5 inches. My dad and I found a huge copperhead while riding motorcycles in the woods one time. It was four lengths of his motorcycle boot sole, which would have been about 50" - Thats huge. No, we didn't kill it, just let it bite and strike our knee height motocross boots a few tims when we poked it. Their venom stinks to high heaven.