Reptiles such as alligators and crocodiles are common in wetlands of some regions. Many species of both alligators and crocodiles are farmed internationally. Crocodilians such as alligators and crocodiles also have gizzards. American crocodiles are more susceptible to cold weather than American alligators. Their predators include larger fish, snakes, turtles, alligators, and birds. It is absent in the snakes, alligators, and crocodiles. Usually American crocodiles are dominant over and more behaviorally aggressive than American alligators. Its diet includes mammals, birds, amphibians, fish, snakes, small turtles, and small alligators. Cott noted little detectable discrepancy in the mating habits of Nile crocodiles and American alligators. Southern Florida is the only place where both alligators and crocodiles live side by side. Crocodiles, alligators, and ducks showed elevated aerobic capacity following exercise training. Tool use by American alligators and mugger crocodiles has been documented. These mangroves support a variety of wildlife including oysters, iguanas, alligators, and ocelots. The blood of alligators and crocodiles contains peptides with antibiotic properties. They are preyed on by large fish, birds, raccoons, and adult American alligators.