The question of whether a crocodile or an alligator is bigger is complex due to the wide variation across different species. Both groups belong to the ancient reptilian order Crocodylia, which also includes the less common caimans and gharials. While they share many similar physical characteristics, their evolutionary paths have led to distinct differences in size and form. Comparing these two families requires looking beyond the average individual and considering the largest species in each group.
General Size Differences
The crocodile family displays a wider range of sizes globally, with many common species growing larger than most alligators. A typical adult American Alligator (Alligator mississippiensis) usually measures between 10 and 15 feet in length, with the heaviest males weighing around 1,000 pounds. Alligators are generally bulkier for their length, possessing a dense, stocky build that helps them ambush prey in freshwater habitats.
Crocodiles are distributed across a greater number of species worldwide, contributing to their broader size spectrum. Most adult crocodile species commonly reach lengths of 14 to 17 feet, surpassing the average alligator. The maximum weight of these species often exceeds that of the largest alligators, making the crocodile family the heavier and generally longer group when considering typical mature individuals.
The Giants: Maximum Species Size
The answer to “what’s bigger” lies in examining the maximum size attained by the largest members of each family. This distinction is clearly held by the crocodile family, specifically the Saltwater Crocodile (Crocodylus porosus). This species is recognized as the largest living reptile on Earth, with mature males regularly exceeding 17 feet in length and often reaching 20 feet.
The largest confirmed Saltwater Crocodiles have been recorded at lengths of up to 23 feet, with body weights reaching over 2,200 pounds. These dimensions set a size benchmark that no alligator species can match. By contrast, the largest alligator, the American Alligator, rarely exceeds 15 feet in length in the wild.
While there are historic and unverified reports of alligators reaching 19 feet, a typical, robust American Alligator male tops out around 14 feet and a weight of about 1,000 pounds. The largest species of alligator is therefore substantially smaller than the largest species of crocodile.
Key Physical Distinctions
Apart from size, there are several reliable physical characteristics used to distinguish crocodiles from alligators. The most immediate difference can be seen in the shape of their snouts. Alligators possess a broad, rounded, U-shaped snout, which gives their head a wider appearance. Crocodiles feature a much narrower, more pointed snout that is distinctly V-shaped.
The arrangement of their teeth when the mouth is closed provides an even more certain identifier. An alligator has an overbite, where its wider upper jaw completely covers the lower jaw, hiding all the bottom teeth from view. Conversely, a crocodile’s upper and lower jaws are nearly the same width, causing the teeth to interlock when the mouth is shut.
This interlocking structure leaves many of the lower teeth visible along the jawline, most notably the large fourth tooth on the lower jaw, which protrudes outside the upper jaw. Finally, the two groups also differ in the presence of tiny sensory pits, called integumentary sensor organs. Crocodiles have these tactile sensory spots covering most of their body scales, while alligators only possess them on the scales of their head and jaw.