Florida is loaded with deadly serpents - cottonmouth moccasins, rattlesnakes and copperheads. Of the three, copperheads are the least risk, but you still wouldn't want to get bit, as they can cause serious permanent injury (nerve damage) and they pose a geniune risk to life of a child or old person.
The cottonmouths are really aggressive. My neighbor called me last week to come and get the snake her cat was playing with on her patio (her husband wasn't home). I took it to the nature preserve, and they confirmed is was a coral snake. They're really nasty, but about the only place they can get you is the webbing between you thumb and index finger.
We also have a big problem with people getting pet pythons, and then letting them got in the everglades when they get too big. This python swallowed a six-foot alligator whole, and then exploded:
You know it's getting bad when the gators are no longer at the top of the everglades food chain.