Gharials are one of the biggest crocodilians (a group that includes alligators, crocodiles and caimans) and has the narrowest snout of these different species. Its common name is due to the bulbous nasal snout of adult males, which looks like an Indian pot with the name 'ghara'. The different physical appearance of males and females is unique to gharials amongst the crocodilians and accentuated by the male’s larger size. Furthermore, unlike other crocodilians, gharials have relatively weak legs, and a fully grown adult cannot raise its body off the ground.
Gharials once thrived throughout all the Indian subcontinent’s major river systems, across the rivers in the north from Pakistan’s Indus River, across the floodplain of the Ganges to the Irrawaddy River of Myanmar. They are extinct today in the Indus River, the Brahmaputra of Bangladesh and Bhutan, and the Irrawaddy River, and they occupy only 2% of their earlier range. Likely the most aquatic crocodilian, the gharial is found in the deep, calmer sections of fast-flowing rivers.
These animals are diurnal and spend much of their day basking in the sun, especially in the winter. They like to revisit the same spot for this purpose, which is always near water. Gharials "gape" while they bask, in order to dissipate excess heat, usually done for 10-20 minutes at a time, while the head is at an angle of 20 degrees. On very hot days they submerge their bodies completely, leaving just their head above the water at an angle of 20-30 degrees. Gharials gather in groups for basking and nesting but are generally solitary. They use three main hunting strategies, one being the sit and wait approach where they float submerged almost completely and stay still until their prey passes by. The second is the sweeping search, which involves a sensory organ located on their scales which senses vibrations in the water as it slowly moves through the water. The third strategy is to strike rapidly. Gharials seem to communicate with vibrations in the water or buzzing sounds made by the males with their snouts.
Gharials are carnivores (piscivores), they almost exclusively eat fish, although rarely they will eat carrion or water birds. Young gharials eat small frogs, insects, and larvae.
Gharials are polygynous. A male will guard his territory, where several females live. It will use its "gharal" during courtship, the lid of cartilage on the male’s nostrils that flaps when he exhales, making a loud buzzing noise. The gharal is also used during territorial defense. Males also hiss, and slap the surface of the water with their jaws. Underwater jaw slapping is used to attract possible mates as well. When a female locates a male, they rub their snouts against each other and the male follows the female around his territorial area. Mating generally occurs from November to February, which is during the dry season. Females dig a nest in a steep sand bank and lay 28-60 eggs in it, usually at night. Incubation lasts for 60-80 days, during which time females are very territorial when near their nest, but will tolerate other females using nests on the same beach. Hatchlings call out when they are ready to emerge, which alerts their mother to dig her eggs out from the nest. Gharials do not carry hatchlings in their jaws. Young remain with their mother for a period of several weeks or several months. Females are mature at 8 years old, when they are 3 meters long, and males at 15 years old and 4 meters long. At this age, a male will grow a ghara on his snout.
Habitat degradation and loss and pose the biggest threat to the gharial’s survival, as the explosion of the human population in the Indian subcontinent encroaches on the river systems that it lives in. Dams, sand mining, irrigation projects, and artificial embankments all have encroached on this species’ habitat, and its range has been reduced to only two percent of its former size. Furthermore, fishermen are in competition for the same food source and there are sometimes accidental or deliberate deaths. Eggs are used for medicinal purposes and adult males are killed for their snouts, which are thought to have aphrodisiac effects.
According to the IUCN Red List, the total gharial population size is less than 235 individuals. This includes fewer than 200 individuals in India and fewer than 35 adults for Nepal. Overall, currently gharials are classified as Critically Endangered (CR) and their numbers today are decreasing.