Alligators and crocodiles are large, semiaquatic reptiles belonging to the ancient order Crocodilia. This lineage of armored predators dates back over 200 million years. Despite their deep evolutionary connection and shared status as apex predators, the two groups are distinct and belong to separate families: Alligatoridae and Crocodylidae. Their visual similarities often lead to questions about whether they share the same habitats in the wild.
The Rare Zone of Coexistence
The answer is yes, but this cohabitation is an exceedingly rare natural phenomenon, occurring in only one place on Earth: the Southern Florida Everglades. Here, the American Alligator (Alligator mississippiensis) and the American Crocodile (Crocodylus acutus) both maintain populations. The American alligator represents the southernmost extent of its species’ range, while the American crocodile is at the northernmost limit of its range in the United States.
This shared territory is possible because the Everglades include a mix of freshwater, brackish water, and saltwater habitats. Alligators generally prefer the freshwater sloughs and marshes of the interior, while crocodiles favor the coastal, brackish mangrove estuaries and saltwater keys. Crocodiles have a higher tolerance for salinity due to specialized salt glands that alligators lack, allowing them to thrive in coastal areas. Alligators are more confined to the freshwater interior.
Global Distribution Patterns
The situation in Florida is an exception, as alligators and crocodiles are geographically separated across nearly all their other ranges. Alligators include only two extant species—the American Alligator and the critically endangered Chinese Alligator (Alligator sinensis)—and are restricted to the United States and China. Their preference for freshwater environments and lower tolerance for cold limits their distribution to specific temperate and subtropical regions.
Crocodiles, in contrast, have a much broader global distribution, spanning tropical regions across Africa, Asia, Australia, and the Americas. Crocodylidae encompasses many species adaptable to diverse aquatic environments, including lakes, rivers, and the open ocean. For example, the Nile crocodile in Africa, the saltwater crocodile in Australia and Southeast Asia, and the various caimans in Central and South America are all geographically isolated from the American alligator’s range.
Key Differences Between Alligators and Crocodiles
Despite their shared membership in the order Crocodilia, alligators and crocodiles exhibit several distinct morphological differences. One reliable method for telling them apart involves examining the shape of the snout. Alligators possess a broad, rounded, U-shaped snout. Crocodiles, conversely, have a longer, narrower, and more pointed V-shaped snout.
This difference in jaw structure also affects the visibility of their teeth when the mouth is closed. An alligator’s upper jaw is wider than its lower jaw, meaning the lower teeth are largely hidden. A crocodile’s upper and lower jaws are nearly the same width, causing the teeth to interlock when the mouth is shut, leaving both the upper and lower teeth visible. Specifically, the fourth tooth on each side of a crocodile’s lower jaw is prominently exposed, fitting into a notch outside the upper jaw.