Alligators and crocodiles are two of the most well-known reptiles in the world. They both belong to the order of Crocodilia, and while they have several similarities, they also have some distinct differences. Alligators are generally smaller than crocodiles and have shorter and rounder snouts. Alligators also have a visible upper fourth tooth in their lower jaw, which is not visible in crocodiles. Alligators are generally found in freshwater habitats, such as lakes, swamps, and rivers, while crocodiles can live in both freshwater and saltwater habitats. Alligators are native to the United States and China, while crocodiles are found in many tropical areas around the world. Alligators are also more docile than crocodiles, and are not considered a threat to humans.