Гхариал: Биология, Эволюция и Распространение.

Crocodilian native to the Indian subcontinent

Speciesbox
|name = Gharial
|fossil range = Pleistocene–Present,
|status = CR
|status system = IUCN3.1
|status ref =
|status2 = CITES A1
|status2 system = CITES
|status2 ref = The name 'fish eating crocodile' is a translation of its Bengali name 'mecho kumhir', with 'mecho' being derived from 'māch' meaning fish and 'kumhir' meaning crocodile. The name 'Indian gharial' has occasionally been used for gharial populations in India.

The evolution of the gharial and its relationship with and divergence from other crocodilians have been a subject of controversy. Some authors assumed that the gharial evolved earlier than the other crocodilians because of its distinct skull shape and dentition, indicating a more advanced level of specialization. Others suggested that it evolved much later than other crocodilians because of its low levels of blood protein divergence. As it shares this trait with the false gharial, it was suggested that they form a sister group. In contrast, it was suggested that the gharial and all the other crocodilians form a sister group as the structure of its tail muscles is unique. Sequencing of a ribosomal segment of mitochondrial DNAs of gharial and false gharial revealed that they share 22 unique nucleotides, a similarity of 94%, supporting the view that they are sister taxa. Analyses of nuclear gene sequences of both species also support the view that they are sister taxa. Molecular genetics and tip dating studies indicates a genetic divergence between the gharial and false gharial in the Eocene about
The genus Gavialis probably originated in the region of India and Pakistan in the Early Miocene. Fossil gharial remains excavated in the Sivalik Hills of Haryana and Himachal Pradesh are dated to between the Pliocene and the Early Pleistocene. Fossil gharial remains were also found at two sites in the Ayeyarwady River valley in central Myanmar, which are dated to the Late Pleistocene. During the Quaternary, Gavialis dispersed as far as Java via the Siva–Malayan route, which did not require saltwater crossings. Fossil remains of Gavialis bengawanicus found on Java were dated to the Early Pleistocene. It represents the only valid extinct Gavialis species.

The gharial is the most thoroughly aquatic crocodilian. Gharials bask daily in the cold season, foremost in the mornings, and prefer sandy and moist beaches. They change their basking pattern with increasing daily temperatures; they start basking earlier in the mornings, move back into the river when it is hot, and return to the beach later in the afternoon. Groups comprising an adult male, several females and subadults have been observed to bask together. Adult males dominate groups and tolerate immature males. The gharial shares riverine habitat with the mugger crocodile (Crocodylus palustris) in parts of its range. They use the same nesting grounds, but differ in the selection of basking sites. The gharial basks close to water on shallow, sandy beaches and lays eggs only in sandy soil near water. The mugger crocodile also basks on sandy beaches, but unlike the gharial climbs steep embankments and rocks, and moves farther away from beaches for both basking and nest building. It also preys on fish, but has a broader prey base than the gharial including snakes, turtles, birds, mammals and dead animals.

The gharial is well adapted to hunting fish underwater because of its sharp interlocking teeth and long narrow snout, which meets little resistance in the water. It does not chew its prey, but swallows it whole. Juvenile gharials were observed to jerk their heads back to manoeuvre fish into their gullets, sliding them in head first. Young gharials feed on insects, tadpoles, small fish and frogs. Adults also feed on small crustaceans. Remains of Indian softshell turtle (Nilssonia gangetica) were also found in gharial stomachs. Gharials tear apart large fish and pick up and swallow stones as gastroliths, probably to aid digestion or regulate buoyancy. Some gharial stomachs also contained jewellery.

Females mature at a body length of around Male gharials mature at 15–18 years of age, when they reach a body length of around and once the ghara is developed. Courting and mating starts by mid February at the end of the cold season. In the dry season, reproductive females observed in the Chambal River routinely move and join female breeding groups to dig nests together. The eggs are the largest of all crocodilians and weigh an average of After 71 to 93 days of incubation, young gharials hatch in July just before the onset of the monsoon. Their sex is most likely determined by temperature, like in most reptiles. In the Chambal River, females were observed to stay close to nest sites and guard young gharials until the shoreline was flooded. VHF radio tracking of a junior male gharial revealed that he was the dominant male guarding nests at a communal nesting site for two years.

Hatchlings range from in body length with a weight of In two years, they grow to a length of and of in three years. Young gharials in their first year of age hide and forage in shallow water preferably in sites that are surrounded by debris of fallen trees. Young gharials move forward by pushing the diagonally opposite legs synchronously. At a young age, they can also gallop but do so only in emergency situations. When they reach a length of about and a weight of about at the age of 8–9 months, they change to an adult pattern of locomotion of pushing forward with hind and front legs simultaneously. Adults do not have the ability to walk on land in the semi upright stance as other crocodilians. When basking on the beach, they often turn round so as to face the water. Water pumps used for pumping water out of the Chambal River have proven to negatively impact the gharial population. Threats in unprotected stretches of the Karnali River include quarrying for boulders, sand mining and unlicensed fishing. In 1976, two breeding centres were established in Uttar Pradesh, one in Kukrail Reserve Forest and one in Katarniaghat Wildlife Sanctuary, with facilities to hatch and raise up to 800 gharials each year for release in rivers. Between 1975 and 1982, sixteen crocodile rehabilitation centers and five crocodile sanctuaries were established in the country. Gharial eggs were initially purchased from Nepal. In 1991, the Ministry of Environment and Forests withdrew funds for the captive breeding and egg collection programs, arguing that the project had served its purpose. In 1997–1998, over 1,200 gharials and over 75 nests were located in the National Chambal Sanctuary, but no surveys were carried out between 1999 and 2003. Gharial eggs collected from wild and captive breeding nests amounted to 12,000 until 2004. Eggs were incubated, and hatchlings were reared to a length of about one meter or more. Despite the release of 142 gharials between 1982 and 2007 into the Ken River, only one adult female gharial was observed in the river in spring 2013, indicating that most of the released gharials had not reproduced. Between 1981 and 2018, a total of 1,365 gharials were released in the Rapti–Narayani river system. Reintroducing gharials helped to maintain this population, but the survival rate of released gharials was rather low. Of 36 marked gharials released in the spring seasons of 2002 and 2003 into the Rapti–Narayani rivers, only 14 were found alive in spring 2004. Releasing captive reared gharials did not contribute significantly to re establishing viable populations. In 2017, members of the Crocodile Specialist Group therefore recommended to foster engagement of local communities in gharial conservation programs. In May 2023, sightings of the Gharial were reported in the Punjab region of Pakistan. This marked the first confirmed sighting of the species in Pakistan after a presumed absence of three decades. In response to these sightings, WWF Pakistan, in collaboration with the other partners, aims to step up conservation efforts for the Gharial. The goal is to ensure that the newly discovered population not only survives but thrives. Pakistan has requested the transfer of hundreds of Gharial crocodiles from Nepal in an effort to reintroduce the species.

The riverbanks of Girwa river were cleared from woody vegetation on sand banks and mid river islands in 2019, and sand was added in 2020 to create an artificial sand bank of about This intervention helped to stabilise and optimise the soil temperature at this site. In 2020, the number of gharial nests on this river stretch increased to 36 from 25 in 2018, and the number of unhatched eggs and dead hatchlings decreased significantly.

As of 1999, gharials were also kept in the Madras Crocodile Bank Trust, Mysore Zoo, Jaipur Zoo and Kukrail Gharial Rehabilitation Centre in India. In Europe, gharials are kept in Prague Zoo and Protivin Crocodile Zoo in the Czech Republic, and the Berlin Zoo in Germany. La Ferme aux Crocodiles, a crocodile farm in France, received six juveniles in 2000 from the Gharial Breeding Centre in Nepal. In the United States, gharials are kept in Busch Gardens Tampa, Cleveland Metroparks Zoo, Fort Worth Zoo, Honolulu Zoo, San Diego Zoo, National Zoological Park, San Antonio Zoo and Aquarium and St. Augustine Alligator Farm Zoological Park. In 2023, Fort Worth Zoo announced the birth of four gharials.

The earliest known depictions of the gharial date to the Indus Valley civilisation. Seals and tablets show gharials with fish in their mouths and surrounded by fish. A tablet shows a deity flanked by a gharial and a fish. These pieces are about 4,000 years old and were found at Mohenjo daro and Amri, Sindh. A gharial is depicted on one of the rock carvings on a pillar of the Sanchi Stupa, which dates to the 3rd century BC. In Hindu mythology, the gharial is the vehicle of the river deity Gaṅgā and of the wind and sea deity Varuna. In the 16th century book Baburnama, Zahir ud din Muhammad Babur accounted of a gharial sighting in the Ghaghara River between Ghazipur and Benares in 1526. In 1915, a British officer observed the traditional method of Kehal fishermen hunting gharials along the Indus. They staked nets about below the waterline close by a sandbank and waited hidden for gharials to come out of the river for basking. After some time, they left their hiding places, prompting the gharials to dart off to the river and get entangled in the nets. Local people in Nepal attributed various mystical powers to the ghara of male gharials and killed them to collect their snouts. Tharu people believed that the ghara would repel insects and pests when burnt in a field, and that gharial eggs would be an effective cough medicine and aphrodisiac. Jewellery found in gharial stomachs may have been the reason for the belief of local people that they would eat humans. Local names for the gharial include 'Lamthore gohi' and 'Chimpta gohi' in Nepali, whereby gohi means crocodile; 'Gharial' in Hindi; 'Susar' in Marathi; 'Nakar' and 'Bahsoolia nakar' in Bihari; 'Thantia kumhira' in Odia, with 'thantia' being derived from the Sanskrit word 'tuṇḍa' meaning beak, snout, elephant's trunk; the male is called 'Ghadiala' and the female 'Thantiana' in Odia.