Behavior and Threat Profile
Green iguanas are not native to Florida. Like the Burmese python, they are the product of the exotic pet trade and a subtropical climate that allows escaped individuals to survive and breed. There are now millions of them in south Florida.
In Leonida they are on the fences, the canal banks, the walls of Vice City's residential districts. They look prehistoric against the background of pastel stucco housing. That contrast is exactly what makes them a detail worth including.
They fall from trees in cold snaps. In real Florida this has become a local news staple: temperatures drop below ten degrees, iguanas enter a cold-induced torpor and fall from whatever tree they were in. Residents are advised not to pick them up as they revive quickly. Leonida presumably has the same problem.