Crocodilians: Alligators, Crocodiles & Gharials

Crocodilians are living archosaurs — the same deep lineage that includes birds — with armour-like scales, powerful tails and a bite adapted for holding large prey. They are ambush hunters of rivers, wetlands and coasts. The identification people need most is alligator versus crocodile: snout shape, visible teeth and salt tolerance. The gharial adds a third silhouette with an extremely slender snout built for fish.

Skin hunting and wetland drainage removed crocodilians from large parts of their historic range in the twentieth century. Legal protection reversed some declines, while river specialists such as the gharial remain near the edge. Parental care — nest guarding and carrying hatchlings — is unusually elaborate among reptiles and is part of why nursery habitat matters as much as adult protection. This page separates the silhouettes; the linked guides document status species by species. WARN crocodilian guides linked from this page cover alligators, crocodiles, caimans and the gharial with status and identification notes. In regions where both alligators and crocodiles occur, snout shape and the visible fourth tooth remain the safest everyday separation for non-specialists.

How to recognise them

The features that separate this group in the field, in the order they are usually most useful.

Snout shape

Alligators have broad U-shaped snouts; crocodiles are typically more V-shaped; gharials have a long thin snout.

Teeth when the mouth is closed

In crocodiles a large fourth lower tooth often shows outside the upper jaw; in alligators it is usually hidden.

Salt tolerance

Crocodiles often have functional salt glands and use brackish or marine water; alligators are mainly freshwater.

Size

Saltwater crocodiles are the largest living reptiles; American alligators are large but typically smaller.

The confusion pairs

Alligator versus crocodile: snout and tooth visibility. Crocodile versus gharial: broad versus needle snout.