Gavialidae

Gavialidae is a family of crocodilians within the order Crocodylia. It comprises two living species, Gavialis gangeticus (the gharial) and Tomistoma schlegelii (the false gharial). Members of Gavialidae are characterized by extremely long, slender snouts adapted to catching fish, and they occupy freshwater river systems in South and Southeast Asia.

Distribution and habitat: The gharial is native to the northern Indian subcontinent, with historic ranges in the Ganges and Brahmaputra river basins. The false gharial occurs in parts of Southeast Asia, including Sumatra, Malay Peninsula, Borneo, and nearby waters. Both species favor large rivers, floodplains, and slow-moving aquatic habitats with abundant fish.

Morphology and behavior: Gavialidae members are highly aquatic, spending much time in rivers. They have long, slender snouts with narrow jaws suited to catching fish. They are often solitary or seen in small groups and breed seasonally. Adults reach up to about 6 meters (gharial) or 3–4 meters (false gharial). Nests are built on sandy banks with eggs incubated for several weeks, a temperature-dependent process.

Taxonomy and evolution: Gavialidae is a distinct family within Crocodylia. Extinct relatives known from fossils extend the lineage back to the Miocene and earlier. The relationship of the two living species within Gavialidae has been clarified by morphological and molecular studies, though past analyses produced differing placements for Tomistoma relative to other crocodilians. In current practice, Gavialis and Tomistoma are treated as the two extant members of Gavialidae.

Conservation: Both species face threats from habitat loss, river modification, pollution, and unsustainable fishing practices. Gavialis gangeticus is listed as Critically Endangered, with small, fragmented populations in India, Nepal, and Bangladesh. Tomistoma schlegelii is listed as Vulnerable, with populations in Indonesia, Malaysia, and surrounding regions. Conservation actions include habitat protection, breeding and reintroduction programs, and protection of nests and riverine habitats.