Ugh... glad we don't have those here. We have rattlers, but they're not too interested in water. I've dealt with them from a distance, which is good enough.
Apparently some cobras have gotten loose in Florida, which already has the biggest rattlesnakes and other nasties. That'll rattle your cage.
http://www.floridatoday.com/story/news/local/environment/2016/04/11/florida-crack-down-cobras/82887418/