Gharial (Gavialis gangeticus): Facts, Snout and Habitat

Appearance

The gharial’s snout is its most striking feature. It is about three and a half times longer than the width of the base of the skull, narrow along its whole length and widened at the tip. The jaws hold roughly 106 to 110 sharp, slender, interlocking teeth, more than most other crocodilians have. The front teeth are the largest.

Adults are dark olive to brownish gray above and yellowish white below. Young gharials are paler, with dark bands and speckles across the back and tail that fade with age. The back is covered with bony plates, called scutes, and the toes are partly webbed.

Adult males are easy to recognize by the ghara, a hollow, bulbous growth over the nostrils at the tip of the snout. The gharial is the only living crocodilian in which adult males carry such an obvious ornament. Its uses are explained in why do male gharials have a bulb on their snout?

Size

The gharial is one of the longest living crocodilians, but it is much more slender than crocodiles of the same length. Females mature at around 2.6 to 3 m (8.5 to 10 ft) and grow to about 4.5 m (15 ft). Males mature at about 4 m (13 ft) and typically reach 5 to 6 m (16 to 20 ft).

Adult males weigh about 160 kg (350 lb) on average, but the largest old males are far heavier, weighing several hundred kilograms. Reports from the early 20th century of gharials 7 m (23 ft) long or more were never reliably measured.

For how this compares with other species, see how big do crocodiles get?

Habitat and range

The gharial is the most fully aquatic of all crocodilians. It lives in large, deep, fairly clear rivers with steady currents, gathering in deep pools at river bends where the flow is slower. It leaves the water almost only to bask and to nest, and it needs open sandbanks and sandbars for both.

Historically, gharials lived in all the major river systems of the northern Indian subcontinent: the Indus in Pakistan, the Ganges and its tributaries in India and Nepal, the Brahmaputra in India and Bangladesh, and the Mahanadi in eastern India, with an old record from Myanmar. Today the species survives in a small fraction of that area. The largest population lives in the National Chambal Sanctuary along the Chambal River, a tributary of the Ganges, with smaller groups in the Girwa, Gandak, Son and Ramganga rivers in India and in the Narayani-Rapti and Babai river systems of Chitwan and Bardiya National Parks in Nepal. Gharials were rediscovered in Pakistan’s Punjab in 2023, after decades without confirmed records.

Gharials use different parts of the river as they grow. Juveniles up to about 1.2 m (4 ft) long prefer basking sites beside water 1 to 3 m (3 to 10 ft) deep, while subadults and adults longer than about 1.8 m (6 ft) favor stretches deeper than 4 m (13 ft). During the monsoon, rivers rise sharply and spread out, and young gharials can be carried far downstream: young gharials found in the Yamuna River in 2012 had probably drifted there from the Chambal during floods.

Evolution and relatives

The gharial’s closest living relative is the false gharial (Tomistoma schlegelii) of Malaysia and Indonesia, which also has a long, narrow snout. DNA studies suggest the two lineages split around 38 million years ago, and that gharials are more closely related to true crocodiles than to alligators and caimans. Fossils show that the genus Gavialis has deep roots in South Asia: gharial fossils from the Pliocene have been found in the Sivalik Hills of northern India, and an extinct relative, Gavialis bengawanicus, lived on the island of Java.

Diet and hunting

Adult gharials eat almost nothing but fish. The long, thin snout meets little resistance in the water, so a gharial can snap it sideways at a passing fish with great speed, and the interlocking teeth hold slippery prey firmly. Prey is swallowed whole, usually head first, and large fish are torn apart.

Gharials hunt in several ways: lying almost submerged and waiting for fish to swim close, slowly sweeping the snout through the water while sensing vibrations with tiny pressure-sensitive organs on their scales, or making a rapid strike. Young gharials eat insects, tadpoles, frogs and small fish, and adults sometimes take crustaceans. Gharials also swallow stones, which may help with digestion or buoyancy. More detail is in what do gharials eat?

Behavior

Gharials spend much of the day in the water and haul out onto sandbanks to bask, especially on cool winter mornings. On hot days they return to the river or lie with their mouths open to shed heat. They usually choose basking spots right at the water’s edge and often turn to face the water, ready to slide in.

On land, adults are clumsy. Their leg muscles are too weak to lift the body into the “high walk” used by crocodiles and alligators, so they push themselves along on their bellies. Small juveniles can still gallop briefly in an emergency. In the water, by contrast, they are agile swimmers.

Gharials gather in loose groups at good basking and nesting sites, often with one dominant adult male, several females and younger animals. Males defend stretches of river during the breeding season. Communication includes head slaps on the water, jaw slaps, hisses and the buzzing and popping sounds made by males with the help of the ghara.

Reproduction and life cycle

Courtship and mating take place in the cool, dry season, roughly from November to February depending on the region. Males buzz, slap the water and display, and pairs rub snouts before mating in the water.

In March to May, females dig nests in dry, sandy riverbanks a few meters from the water, often nesting in groups at the same site. A clutch usually contains about 20 to 60 eggs, and very large females can lay close to 100. The eggs are the largest of any crocodilian, averaging about 160 g (5.6 oz). After about 60 to 90 days, the young hatch, usually in June or July, just before the monsoon floods. As in other crocodilians, nest temperature during incubation decides whether the hatchlings are male or female.

Females dig the hatchlings out when they hear them calling, and they stay near the young in shallow water for weeks, often until the monsoon floods disperse them. Hatchlings measure about 35 cm (14 in) and grow to more than 1 m (3.3 ft) within about three years. Females mature at around 8 years or older and males at about 15 years or more. Lifespan in the wild is not well known; gharials are thought to live for several decades, and one captive animal at London Zoo was estimated to be about 29 years old.

Predators and threats

Adult gharials have no regular natural predators. Eggs and hatchlings are eaten by golden jackals, mongooses, monitor lizards, wild pigs and rats, and only a small share of the young survive their first years.

People are the main threat. Gharials were once hunted for their skins and as trophies, their eggs were collected for food and folk medicine, and males were killed for the ghara, which was wrongly believed to have medicinal powers. Today the greatest dangers are habitat loss and fishing. Dams, barrages and irrigation channels change river flows; sand mining and farming destroy nesting banks; overfishing reduces food; and gharials drown after becoming tangled in gill nets. Between December 2007 and March 2008, more than 100 gharials were found dead in the Chambal River, and tests later pointed to toxic metals such as lead and cadmium, along with parasites.

Conservation status

The IUCN Red List has classed the gharial as Critically Endangered since 2007. The wild population is thought to have fallen from 5,000 to 10,000 animals in the 1940s to fewer than 250 mature adults by 2006, a decline of 96 to 98 percent. The species is protected under India’s Wildlife Protection Act and Nepal’s national parks law, and international trade is banned under CITES Appendix I.

Since the late 1970s, India and Nepal have collected eggs, raised young gharials and released thousands of them into protected rivers. Releases kept some populations alive, but many released animals died, and conservationists now place more weight on protecting wild nests, basking sites and river habitat. The IUCN’s 2019 assessment estimated about 650 mature adults in the wild. The full story is in are gharials endangered?

Gharials and people

Gharials have lived alongside people for thousands of years. Seals and tablets from the Indus Valley civilization, about 4,000 years old, show gharials with fish in their mouths, and in Hindu tradition the gharial is the vehicle of the river goddess Ganga.

Despite their size, gharials are not a danger to people. Jewelry has occasionally been found in gharial stomachs, which helped fuel local beliefs that they eat humans, but there is no reliable evidence of gharials preying on people. Their slim jaws and thin teeth are designed for fish. Today gharials are a draw for wildlife tourism, especially on boat trips in the National Chambal Sanctuary. To see how they differ from their broad-snouted relatives, see crocodile vs gharial.