Gators prey on things like fish, turtles, raccoons, wading birds, ducks, and dogs. Boy do they like dogs. Even a small, 6’ gator can dispatch a large dog quite efficiently. They are known to attack and kill small children, who kind of fit the above profile. Gators are not like Nike crocodiles, who will go after large terrestrial animals and adult humans.
Now bull gators are territorial. They will defend their territory from swimmers or wading fishermen. If they dispatch someone in the process, they will not pass up a free meal. Fisherman say that if they see a big gator, they leave him to his territory.
Given the absurdly large numbers of gators there are in FL and even numbers of big gators.... 10’ plus, there are very few attacks.
I dove Alexander Springs and there was a small gator there.... about 6 feet or a bit more. She was busily hunting a school of plescostomus cats, an invasive species. She was totally uninterested in divers.
Gators are strictly fresh water. Sea water rapidly makes them ill. But any body of water larger than a teacup in FL can have gators. They are often found in backyard swimming pools. The assumption should be that if it is wet, it has gators.
The American Crocodile is found in south FL and the upper keys. They like salt and brackish water. Their numbers are small. But they can get large and are potentially quite dangerous. But there are very few attacks.
Another thing, both gators and crocs can move far faster than most people imagine.
Just for a sense of scale, fresh water amoebas kill more people in FL than gators. It is just like the beaches, getting killed by someone driving on the beach is more likely than being killed by a shark.