Alligators
Alligators are a common sight in Miami. It's common to come across them at the water's edge, and there are signs everywhere to remind us of this. They hide very well in the tall grass, and don't be fooled into thinking that there are only small ones in town. The danger certainly lies in lowering our guard, as we don't expect to find such an animal in town.

Fire ants
Fire ants, whose name doesn't bode well, are red ants slightly larger than those found in France. Indeed, their name is not insignificant and reflects the pain of their stings. If you have the misfortune to inadvertently trample their nest, they will attack by the hundreds. Their nests are not very conspicuous, and can be identified by a grass-free area and finely ground earth.

Manatees
I was lucky enough to see manatees feeding in a canal. It's an impressive animal, totally harmless and doesn't seem particularly afraid of humans, which is perfect for taking the time to observe it.

Iguanas
Iguanas, too, are harmless, but seeing this kind of reptile, some of which can grow up to 1.5 m long, can be surprising.

Here's an overview of the species you may come across while fishing in South Florida's cities. These are wild animals, and with some it's best to keep your distance.