Alligators and crocodiles are frequently confused, yet they belong to separate families within the order Crocodylia. While both are powerful semi-aquatic hunters with armored bodies and long snouts, key distinctions in their physical structure, geographic range, and behavior allow for clear identification.
Snout Shape and Visible Teeth
The most immediate way to distinguish the two is by examining the shape of their snout and the arrangement of their teeth when the mouth is closed. An alligator possesses a broad, rounded, U-shaped snout, suited for crushing hard-shelled prey like turtles. When an alligator closes its mouth, the wider upper jaw completely conceals the lower teeth, fitting them into sockets. This gives the alligator a less “toothy” appearance when resting.
In contrast, a crocodile has a narrower, V-shaped snout, which may be more effective for catching fish. The upper and lower jaws are nearly the same width, causing the teeth to interlock when the mouth shuts. This alignment results in the prominent fourth tooth on the lower jaw remaining visible outside the upper jaw, creating a distinctive, almost permanent grin.
Geography and Preferred Habitat
The global distribution of these two crocodilians is quite different, largely due to their tolerance for salt water. Alligators are primarily restricted to two regions: the southeastern United States, where the American Alligator thrives, and a small population of the Chinese Alligator in the Yangtze River basin of China. They strongly prefer freshwater environments, such as swamps, marshes, lakes, and slow-moving rivers. This preference is because their salt glands, which help regulate sodium levels, are not highly effective.
Crocodiles have a much broader worldwide range, inhabiting tropical regions across Africa, Asia, Australia, and the Americas. This wide distribution is possible because crocodiles possess specialized lingual salt glands that efficiently excrete excess salt. This adaptation allows many crocodile species to tolerate and thrive in brackish estuaries, mangrove swamps, and even marine coastal waters. For instance, the Saltwater Crocodile is often found many miles from the nearest freshwater source.
Temperament and Maximum Size
Differences in behavior and scale are also noticeable. Crocodiles are generally considered to exhibit more aggressive and reactive behavior toward humans compared to alligators. Species like the Nile Crocodile and the Saltwater Crocodile are responsible for a significantly higher number of attacks globally. Alligators tend to be more reserved, usually preferring to retreat when approached by people unless they are provoked, defending their young, or cornered.
Regarding maximum size, crocodiles typically grow larger than alligators. The American Alligator, the largest alligator species, usually reaches a maximum length of about 15 feet. However, the largest crocodile species, the Saltwater Crocodile, can regularly exceed 20 feet in length, making it the largest living reptile on Earth.