crocodilian

Crocodilian is a term for the reptiles of the order Crocodylia, including alligators, caimans, true crocodiles, and gharials. The three living families—Alligatoridae, Crocodylidae, and Gavialidae—comprise about two dozen species found in tropical and subtropical regions of Africa, the Americas, Asia, and Australia.

Crocodilians are semi-aquatic, ectothermic predators with elongated snouts, conical teeth, and tough, scaly skin covered with osteoderms (scutes). They have muscular tails for swimming, strong jaws, and eyes and nostrils positioned on the top of the head to see and breathe while mostly submerged. Most species retain a four-chambered heart, enabling a degree of separation between lung and body circulation.

They inhabit rivers, lakes, swamps, and estuaries; saltwater crocodiles can travel across seas and inhabit coastal regions. They are distributed across Africa, the Americas, southern and southeastern Asia, and Australia, avoiding colder climates.

Crocodilians are oviparous; females guard nests and care for hatchlings. Eggs exhibit temperature-dependent sex determination. Parental care can last weeks to months, with juveniles remaining with adults for some time.

Conservation status varies by species. Many face threats from habitat loss, hunting, and collection for meat and leather. Some populations are stable or increasing due to protections and management, while others remain endangered or vulnerable. Crocodilians are important apex predators in their ecosystems and have cultural and economic significance in some regions.