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The gharial (Gavialis gangeticus), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are Template:Cvt long, and males Template:Cvt. Adult males have a distinct boss at the end of the snout, which resembles an earthenware pot known as a ghara, hence the name "gharial". The gharial is well adapted to catching fish because of its long, narrow snout and 110 sharp, interlocking teeth.
The gharial probably evolved in the northern Indian subcontinent. Fossil gharial remains were excavated in Pliocene deposits in the Sivalik Hills and the Narmada River valley. It currently inhabits rivers in the plains of the northern part of the Indian subcontinent. It is the most thoroughly aquatic crocodilian, and leaves the water only for basking and building nests on moist sandbanks. Adults mate at the end of the cold season. Females congregate in spring to dig nests, in which they lay 20–95 eggs. They guard the nests and the young, which hatch before the onset of the monsoon. The hatchlings stay and forage in shallow water during their first year, but move to sites with deeper water as they grow.
The wild gharial population has declined drastically since the 1930s and is limited to only 2% of its historical range today. Conservation programmes initiated in India and Nepal focused on reintroducing captive-bred gharials since the early 1980s. Loss of habitat because of sand mining and conversion to agriculture, depletion of fish resources and detrimental fishing methods continue to threaten the population. It has been listed as critically endangered on the IUCN Red List since 2007.
The oldest known depictions of the gharial are about 4,000 years old and were found in the Indus Valley. Hindus regard it as the vehicle of the river deity Gaṅgā. Local people living near rivers attributed mystical and healing powers to the gharial, and used some of its body parts as ingredients of indigenous medicine.
EtymologyEdit
The name 'gharial' is derived from the Hindustani word 'ghara' for an earthen pot, in reference to the nasal protuberance on the adult male's snout. It is also called 'gavial'.<ref name=Stevenson2010>Template:Cite book</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.<ref name=Daniel1983>Template:Cite book</ref> The name 'Indian gharial' has occasionally been used for gharial populations in India.<ref name=Bustard1977>Template:Cite journal</ref>
TaxonomyEdit
Lacerta gangetica was the scientific name proposed by Johann Friedrich Gmelin in 1789.<ref>Template:Cite book</ref> Gmelin followed Carl Linnaeus who proposed Lacerta in 1758 to include other crocodiles and various lizards known at the time.<ref>Template:Cite book</ref>
The gharial was placed in the genus Crocodilus by subsequent naturalists:
- Crocodilus gavial by Pierre Joseph Bonnaterre in 1789.<ref>Template:Cite book</ref>
- Crocodilus longirostris by Johann Gottlob Theaenus Schneider in 1801.<ref>Template:Cite book</ref>
- Crocodilus arctirostris by François Marie Daudin in 1802.<ref>Template:Cite book</ref>
- Longirostres was a subgroup proposed by Georges Cuvier in 1807 for crocodiles with a long snout. He placed Crocodilus gangeticus with the type locality "Ganges" and Crocodilus tenuirostris without locality into this group.<ref>Template:Cite journal</ref>
The generic name Gavialis was proposed by Nicolaus Michael Oppel in 1811 for crocodiles with a cylindrical-shaped back. He placed this genus in the family Crocodilini.<ref>Template:Cite book</ref> Rhamphostoma was proposed by Johann Georg Wagler in 1830 who considered this genus to contain two species, Crocodilus gangeticus and C. tenuirostris.<ref>Template:Cite book</ref>
The family name Gavialidae was proposed by Arthur Adams in 1854 with Gavialis as the only genus in this family.<ref>Template:Cite book</ref> Gavialis gangetica was the scientific name used by Albert Günther in 1864 who considered L. gangetica, C. longirostris and C. tenuirostris as synonyms and Gavialis a monotypic taxon.<ref>Template:Cite book</ref> John Edward Gray reviewed zoological specimens in the collection of the Natural History Museum, London. He also considered the gharial monotypic in 1869. He placed it in the family Gavialidae together with the false gharial (Tomistoma schlegelii) because both have long, slender jaws and similar dentition.<ref name=Gray1896>Template:Cite journal</ref>
Gharialis hysudricus proposed by Richard Lydekker in 1886 was based on a fossil skull from the Sivalik Hills that was larger than gharial fossil skulls known at the time.<ref>Template:Cite book</ref> This name is considered to be a junior synonym of Gavialis gangeticus.<ref name=Martin2018>Template:Cite journal</ref>
EvolutionEdit
The evolution of the gharial and its relationship with and divergence from other crocodilians have been a subject of controversy.<ref name=Brochu97>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref> Analyses of nuclear gene sequences of both species also support the view that they are sister taxa.<ref name="Harshman2003">Template:Cite journal</ref><ref>Template:Cite journal</ref> Molecular genetics and tip dating studies indicates a genetic divergence between the gharial and false gharial in the Eocene about Template:Mya.<ref name="LeeYates2018">Template:Cite journal</ref>
The genus Gavialis probably originated in the region of India and Pakistan in the Early Miocene.<ref name=Delfino>Template:Cite journal</ref> Fossil gharial remains excavated in the Sivalik Hills of Haryana and Himachal Pradesh are dated to between the Pliocene and the Early Pleistocene.<ref>Template:Cite journal</ref> Fossil gharial remains were also found at two sites in the Ayeyarwady River valley in central Myanmar, which are dated to the Late Pleistocene.<ref name=WinKoKo>Template:Cite journal</ref> 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.<ref name=Delfino/> G. bengawanicus fossils found in Thailand's Nakhon Ratchasima Province support the hypothesis of gharial dispersal through riverine systems.<ref>Template:Cite journal</ref> It represents the only valid extinct Gavialis species.<ref>Template:Cite journal</ref>
PhylogenyEdit
The below cladogram of the major extant crocodile groups is based on the latest molecular studies and shows the gharial's close relationship to the false gharial, and how the gavialids and crocodiles are more closely related than the alligatoroids:<ref name=Harshman2003/><ref name=Gatesy2008>Template:Cite journal</ref><ref name=Erickson_al2012>Template:Cite journal</ref><ref name=LeeYates2018/><ref name=Hekkala2021>Template:Cite journal</ref> Template:Clade
Here is a more detailed cladogram that shows the gharial's proposed placement within Gavialidae, including extinct members:<ref name=LeeYates2018/>
CharacteristicsEdit
Template:Multiple image The gharial is olive-coloured, with adults being darker than young, which have dark brown cross bands and speckles.<ref name=Boulenger>Template:Cite book</ref><ref>Template:Cite book</ref> Its back turns almost black at 20 years of age, but its belly is yellowish-white. It has four transverse rows of two scales on the neck, which continue along the back.<ref name=Brazaitis>Template:Cite journal</ref> Scutes on the head, neck and back form a single continuous plate composed of 21 to 22 transverse series, and four longitudinal series. Scutes on the back are bony, but softer and feebly keeled on the sides. The outer edges of the forearms, legs, and feet have crests jutting out; fingers and toes are partly webbed.<ref name=Boulenger/>
Its snout is very long and narrow, widened at the end, and with 27 to 29 upper teeth and 25 or 26 lower teeth on each side. The front teeth are the largest. The first, second, and third lower jaw teeth fit into spaces in the upper jaw. The extremely long mandibular symphysis extends to the 23rd or 24th tooth. The snout of adult gharials is 3.5 times longer than the width of the skull's base.<ref name=Boulenger/> Because of this long snout the gharial is especially adapted to catching and eating fish.<ref name=Stevenson2010 /> The nasal bones are rather short and widely spaced from the premaxillae. The jugal bone is raised.<ref name=Boulenger/> It becomes proportionally thicker with age.<ref name=Whitaker07/> Two individuals in the weight range of Template:Cvt had an average measured bite force of Template:Cvt.<ref name=Erickson_al2012/>
Male gharials develop a hollow bulbous nasal protuberance at the tip of the snout upon reaching sexual maturity.<ref name=Brazaitis/> This protuberance resembles an earthen pot known locally as "ghara". The male's ghara starts growing over the nostrils at an age of 11.5 years and measures about Template:Cvt at an age of 15.5 years. It enables the males to emit a hissing sound that can be heard Template:Cvt away; this sound is thought to attract females.<ref name=Biswas1977>Template:Cite journal</ref> The gharial is the only living crocodilian with such visible sexual dimorphism.<ref name=Whitaker07>Template:Cite journal</ref> Mature male gharials have larger skulls than females, exceeding a basal length of Template:Cvt and a width of Template:Cvt.<ref>Template:Cite journal</ref>
Female gharials reach sexual maturity at a body length of Template:Cvt and grow up to Template:Cvt. Males mature at a body length of at least Template:Cvt and grow up to a length of Template:Cvt.<ref name=Whitaker1982>Template:Cite journal</ref> Adult males weigh about Template:Cvt on average, but can reach a weight of up to Template:Cvt.<ref name=Stevenson2010/><ref>Template:Cite journal</ref> The gharial is among the largest living crocodilians, with the heaviest recorded male weighing Template:Cvt.<ref name=maskey94/> A Template:Cvt long gharial was claimed to have been killed in the Ghaghara River in Faizabad in August 1920, though no reliable measurements were taken.<ref>Template:Cite journal</ref> Male gharials with an alleged length of Template:Cvt were sighted around the turn of the 20th century in Indian rivers.<ref>Template:Cite book</ref> Overall, the gharial is less massive when compared to other crocodilians of similar length; a Template:Cvt long gharial weighed around Template:Cvt, while a Template:Cvt long Nile crocodile weighed Template:Cvt.<ref>Template:Cite book</ref>
Distribution and habitatEdit
Template:Multiple image The gharial once thrived in all the major river systems of the northern Indian subcontinent, from the Indus River in Pakistan, the Ganges in India, the Brahmaputra River in northeastern India and Bangladesh to the Irrawaddy River in Myanmar.<ref name=Whitaker07/> In the early 20th century, it was considered common in the Indus River and its Punjabi tributaries.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> By the early 1980s, it was almost extinct in the Indus.<ref name=Whitaker1982/> During surveys in 2008 and 2009, no gharial was sighted in the river.<ref name=Stevenson2010/> It was also present in India's Godavari River but was hunted to extinction between the late 1940s and the 1960s.<ref>Template:Cite journal</ref> It was considered extinct in the Koshi River since 1970.<ref>Template:Cite journal</ref> In the 1940s, it was numerous in the Barak River in Assam, which held big fish at the time including golden mahseer (Tor putitora).<ref>Template:Cite journal</ref> A few individuals were also sighted in tributaries of the Barak River in Assam, Mizoram and Manipur up to 1988, but surveys were not carried out.<ref>Template:Cite journal</ref> In 1927, a gharial was shot in the Shweli River in Myanmar, a tributary of the Ayeyawady River.<ref>Template:Cite journal</ref> This is the only authenticated record in the country attesting the survival of gharials into the 20th century. Whether gharials still live in the Shweli River today is possible but remained unclear in 2012.<ref name=WinKoKo/>
By 1976, its global range had decreased to only 2% of its historical range, and fewer than 200 gharials were estimated to survive.<ref name=Whitaker07/> It is locally extinct in Pakistan, Bhutan and Myanmar.<ref name=Stevenson2010/> Since the early 1980s, the population has been reinforced with captive-bred gharials that were released into wild habitats in India and Nepal.<ref name=iucn/> As of 2019, the global population was estimated to comprise at maximum 900 individuals, including about 600 mature adults in six major subpopulations along Template:Cvt of river courses and another 50 mature adults in eight minor subpopulations along Template:Cvt of river courses.<ref name=iucn />
In Nepal, small populations are present and slowly recovering in tributaries of the Ganges, such as the Karnali–Babai River system in Bardia National Park<ref name=maskey94>Template:Cite book</ref><ref name=Bashyal_al2021>Template:Cite journal</ref> and the Narayani–Rapti river system in Chitwan National Park.<ref>Template:Cite report</ref><ref name=Ballouard_al2010>Template:Cite journal</ref> In spring 2017, the Babai River was surveyed using an unmanned aerial vehicle, which detected 33 gharials on a stretch of Template:Cvt.<ref>Template:Cite journal</ref>
In India, gharial populations are present in the:
- Ramganga River in Corbett National Park, where five gharials were recorded in 1974. Captive-bred gharials were released since the late 1970s. The population is breeding since 2008, and increased to about 42 adults by 2013.<ref>Template:Cite journal</ref><ref>Template:Cite book</ref> Most of them congregate along an Template:Cvt long stretch of the Kalagarh Reservoir's shoreline. Surveys in 2015 revealed a population of 90 gharials including 59 breeding adults.<ref>Template:Cite book</ref>
- Ganges, where 494 gharials were released between 2009 and 2012 in Hastinapur Wildlife Sanctuary.<ref>Template:Cite book</ref><ref>{{#invoke:citation/CS1|citation
|CitationClass=web }}</ref>
- Girwa River in Katarniaghat Wildlife Sanctuary where the small breeding population was reinforced with captive reared gharials since 1979.<ref name=Rao1992>Template:Cite journal</ref> A total of 909 gharials were released until 2006, but only 16 nesting females were recorded in the same year.<ref name=iucn/> In December 2008, 105 individuals were counted including 35 adults. In spring 2009, 27 nests were detected in seven sites.<ref>Template:Cite journal</ref> The number of nest sites decreased from seven in 2017 to two in 2019, possibly due to the upgrowth of woody vegetation and reduced river flow near sandbanks.<ref>Template:Cite journal</ref>
- Gandaki River downstream the Triveni barrage west of Valmiki Tiger Reserve and adjacent to Sohagi Barwa Sanctuary.<ref>Template:Cite book</ref> The population increased from 15 gharials in 2010 to 54 individuals recorded in March 2015 on a stretch of Template:Cvt. 35 of these gharials were wild-born.<ref>Template:Cite book</ref> The population in the Template:Cvt long river section from the Triveni barrage to the confluence with the Ganges was estimated at 196 adults, 161 juveniles, 140 sub-adults and 37 yearlings between post-monsoon season of 2019 and pre-monsoon 2021.<ref>Template:Cite journal</ref>
- Chambal River in National Chambal Sanctuary where 107 gharials were recorded in 1974. Captive-bred gharials were released since 1979, and the population increased to 1,095 gharials in 1992.<ref name=Hussain1999>Template:Cite journal</ref> Between December 2007 and March 2008, 111 gharials were found dead.<ref name=Nawab_al2013>Template:Cite book</ref> A total of 948 gharials were counted during surveys in 2013 along the protected river stretch of Template:Cvt.<ref>Template:Cite book</ref> In 2017, this population was estimated at 617–761 mature individuals and more than 1250 individuals by two different survey teams; 411 nests were found.<ref name=Khandal_al2017>Template:Cite journal</ref>
- Parbati River, a tributary of the Chambal River, where gharials started using a few sand banks since about 2015; 29 gharials were observed in 2016 and 251 hatchlings counted at two nesting sites in 2017.<ref name=Khandal_al2017/>
- Yamuna River where eight young gharials were detected in autumn 2012 near the confluence of the Ken and Yamuna Rivers. They were probably offspring of the breeding population in the Chambal River and had drifted downriver during monsoon floods.<ref>Template:Cite journal</ref>
- Son River where 164 captive-reared gharials were released between 1981 and 2011.<ref name=Nair2013>Template:Cite book</ref>
- Koshi River in Bihar where two gharials were sighted basking in late January 2019 during a survey targeting South Asian River Dolphins (Platanista gangetica) on a stretch of about Template:Cvt. This is the first record of wild gharials in the river since the 1970s.<ref>Template:Cite journal</ref>
- Mahanadi River in Odisha's Satkosia Gorge Sanctuary where about 700 gharials were released between 1977 and the early 1990s.<ref name=Rao1992/><ref>Template:Cite journal</ref> During a 1.5 year long survey in 2005–2006, only one male and one female gharial were detected moving together and sharing sand banks in the river.<ref>Template:Cite journal</ref>
Between 1979 and 1993, less than 20 individuals were sighted in the upper reaches of the Brahmaputra River between Kaziranga National Park and Dibru-Saikhowa National Park. This population had declined due to commercial fishing, poaching, encroachment by local people in gharial breeding grounds and siltation of river beds following deforestation. In 1998, it was not considered to be viable.<ref>Template:Cite journal</ref> About 30 gharials were observed in small lakes and tributaries of the Brahmaputra River in Assam between 2004 and 2007.<ref>Template:Cite book</ref>
In Bangladesh, gharials were recorded in Padma, Jamuna, Mahananda and Brahmaputra rivers between 2000 and 2015.<ref>Template:Cite book</ref>
Behaviour and ecologyEdit
Template:Multiple image The gharial is the most thoroughly aquatic crocodilian.<ref name=Whitaker1982/> It leaves the water only for basking on riverbanks.<ref name=Bustard1977/> Being cold-blooded, it seeks to cool down during hot times and to warm up when ambient temperature is cool.<ref>Template:Cite book</ref> 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.<ref name=Whitaker1982/> Large groups of young, subadult and adult gharials form in December and January to bask. Adult males and females associate by mid February.<ref name=Lang2013>Template:Cite book</ref>
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.<ref>Template:Cite journal</ref> 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.<ref name=Choudhary_al2018>Template:Cite journal</ref> It also preys on fish, but has a broader prey base than the gharial including snakes, turtles, birds, mammals and dead animals.<ref>Template:Cite book</ref>
Feeding ecologyEdit
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.<ref name=Whitaker1982/> Stones weighing about Template:Cvt were found in a gharial's stomach that was shot in the Sharda River in 1910.<ref>Template:Cite journal</ref>
ReproductionEdit
Females mature at a body length of around Template:Cvt.<ref name=Whitaker1982/> Captive females breed at a body length of Template:Cvt.<ref>Template:Cite journal</ref> Male gharials mature at 15–18 years of age, when they reach a body length of around Template:Cvt and once the ghara is developed.<ref name=Whitaker07/> The ghara is apparently used to indicate sexual maturity, as a sound resonator when bubbling underwater or for other sexual behaviours.<ref>Template:Cite journal</ref>
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 Template:Cvt and join female breeding groups to dig nests together.<ref name=Lang2013/> They select sites in riverside sand or silt banks located between Template:Cvt away from the water and above a water level of Template:Cvt. These nests are Template:Cvt deep with a diameter of about Template:Cvt. Females have been observed digging "trial nests".<ref>Template:Cite journal</ref> Between end of March and early April, they lay 20–95 eggs.<ref name=Whitaker1982/> A record clutch with 97 eggs was found in Katarniaghat Wildlife Sanctuary.<ref>Template:Cite journal</ref> The eggs are the largest of all crocodilians and weigh an average of Template:Cvt.<ref name=Whitaker07/> Each egg is Template:Cvt long and Template:Cvt wide.<ref name=Smith1931>Template:Cite book</ref> 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.<ref name=Whitaker1982/> Females dig up the hatchlings in response to hatching chirps, but do not assist them to reach the water.<ref name=Whitaker07/> They stay at nesting sites until monsoon floods arrive and return after monsoon.<ref name=Lang2013/>
Captive male gharials observed in the 1980s did not participate in guarding nests. A captive male gharial was observed to show an interest in hatchlings and was allowed by the female to carry hatchlings on his back.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite book</ref> The availability of open riverbanks at potential nesting sites is crucial for reproductive success.<ref>Template:Cite journal</ref>
DevelopmentEdit
Hatchlings range from Template:Cvt in body length with a weight of Template:Cvt. In two years, they grow to a length of Template:Cvt and of Template:Cvt in three years.<ref name=Whitaker1982/> Gharials hatched and raised in Nepal's Gharial Conservation and Breeding Center measured Template:Cvt and weighed Template:Cvt at the age of 45 months in April 2013. They consumed up to Template:Cvt of fish per individual and month. By the age of 75 months, they had gained Template:Cvt in weight and grown Template:Cvt reaching body lengths of Template:Cvt.<ref>Template:Cite journal</ref>
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.<ref name=Whitaker1982/> A study along a Template:Cvt stretch of the Chambal River revealed that juvenile gharials up to a body length of Template:Cvt prefer basking sites where the mid river water is Template:Cvt deep. As their body size increases, they move to sites with deeper water. Subadult and adult gharials above a body length of Template:Cvt prefer sites where the water is deeper than Template:Cvt.<ref>Template:Cite journal</ref>
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 Template:Cvt and a weight of about Template:Cvt 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.<ref name=Bustard1977/>
ThreatsEdit
The gharial population is estimated to have declined from 5,000–10,000 individuals in 1946 to fewer than 250 individuals in 2006, a decline of 96–98% within three generations. Gharials were killed by fishermen, hunted for skins, trophies and indigenous medicine, and their eggs collected for consumption. The remaining individuals form several fragmented subpopulations. Hunting is no longer considered a significant threat. However, the wild population declined from an estimated 436 adult gharials in 1997 to fewer than 250 mature individuals in 2006. One reason for this decline is the increased use of gill nets for fishing in gharial habitat. The other major reason is the loss of riverine habitat as dams, barrages, irrigation canals and artificial embankments were built; siltation and sand-mining changed river courses; and land near rivers is used for agriculture and grazing by livestock.<ref name=iucn/>
When 111 dead gharials were found in the Chambal River between December 2007 and March 2008, it was initially suspected that they had died either because of toxicants or the illegal use of fish nets, in which they became entrapped in and subsequently drowned.<ref name=Nawab_al2013/> Later post mortem pathological testing of tissue samples revealed high levels of heavy metals such as lead and cadmium, which together with stomach ulcers and protozoan parasites reported in most necropsies were thought to have caused their deaths.<ref>Template:Cite journal</ref> Water pumps used for pumping water out of the Chambal River have proven to negatively impact the gharial population.<ref>Template:Cite journal</ref>
Threats in unprotected stretches of the Karnali River include quarrying for boulders, sand mining and unlicensed fishing.<ref name=Bashyal_al2021/>
ConservationEdit
The gharial is listed on CITES Appendix I.<ref name=iucn/> In India, it is protected under the Wildlife Protection Act of 1972.<ref name=Whitaker07/> In Nepal, it is fully protected under the National Parks and Wildlife Conservation Act of 1973.<ref name="maskey94"/>
Reintroduction programmesEdit
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Since the late 1970s, the gharial conservation approach was focused on reintroduction. Rivers in protected areas in India and Nepal used to be restocked with captive bred juvenile gharials. Gharial eggs were incubated, hatched and juvenile gharials raised for two to three years and released when about one metre in length.<ref name=iucn/>
In 1975, the Indian Crocodile Conservation Project was set up under the auspices of the Government of India, initially in Odisha's Satkosia Gorge Sanctuary. It was implemented with financial aid of the United Nations Development Fund and the Food and Agriculture Organization. The country's first gharial breeding center was built in Nandankanan Zoological Park. A male gharial was flown in from Frankfurt Zoological Garden to become one of the founding animals of the breeding program. In subsequent years, several protected areas were established.<ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref> 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.<ref name=Whitaker07/> More than 5,000 gharials were released into Indian rivers between the early 1980s and 2006.<ref>Template:Cite journal</ref> 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.<ref name=Nair2013/> Juvenile gharials have also been released into the Beas River in Punjab, India.<ref name=iucn/>
In Nepal, wild eggs collected along rivers have been incubated in the Gharial Conservation and Breeding Center in Chitwan National Park since 1978. The first batch of 50 gharials was released in spring 1981 into the Narayani River. In subsequent years, gharials were also released into five other rivers in the country.<ref name="maskey94"/> In 2016, this center was overcrowded with more than 600 gharials aged between 5 and 12 years, and many were too old to be released.<ref name=Lang2017>Template:Cite journal</ref> Between 1981 and 2018, a total of 1,365 gharials were released in the Rapti–Narayani river system.<ref>Template:Cite journal</ref> 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.<ref name=Ballouard_al2010/> This reintroduction programme has been criticised in 2017 as not being comprehensive and coordinated, as often too old and unsexed gharials were released at disturbed localities during unfavourable cold months and without assessing the efficiency of these releases.<ref name=Lang2017/> It has been suggested to instead leave wild nests in place, increase protection of nesting and basking sites and monitor the movement of gharials.<ref>Template:Cite journal</ref>
Releasing captive-reared gharials did not contribute significantly to re-establishing viable populations.<ref name=iucn/> Monitoring of released gharials revealed that the reintroduction programmes did not address multiple factors affecting their survival. These factors include disturbances from diversions of river courses, sand mining, cultivation of riversides, fishing by local people and mortality related to fishing methods like the use of gill nets and dynamite.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> In 2017, members of the Crocodile Specialist Group therefore recommended to foster engagement of local communities in gharial conservation programs.<ref>Template:Cite journal</ref>
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.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In situ projectsEdit
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 Template:Cvt. 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.<ref>Template:Cite journal</ref>
In captivityEdit
As of 1999, gharials were also kept in the Madras Crocodile Bank Trust, Mysore Zoo, Jaipur Zoo and Kukrail Gharial Rehabilitation Centre in India.<ref>Template:Cite journal</ref>
In Europe, gharials are kept in Prague Zoo and Protivin Crocodile Zoo in the Czech Republic, and the Berlin Zoo in Germany.<ref>Template:Cite book</ref> La Ferme aux Crocodiles, a crocodile farm in France, received six juveniles in 2000 from the Gharial Breeding Centre in Nepal.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
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.<ref name=Whitaker07/> Bronx Zoo and Los Angeles Zoo received gharials in 2017.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In 2023, Fort Worth Zoo announced the birth of four gharials.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In cultureEdit
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.<ref>Template:Cite book</ref>
A gharial is depicted on one of the rock carvings on a pillar of the Sanchi Stupa, which dates to the 3rd century BC.<ref>Template:Cite journal</ref> In Hindu mythology, the gharial is the vehicle of the river deity Gaṅgā and of the wind and sea deity Varuna.<ref>Template:Cite book</ref>
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.<ref>Template:Cite book</ref>
In 1915, a British officer observed the traditional method of Kehal fishermen hunting gharials along the Indus. They staked nets about Template:Convert 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.<ref>Template:Cite journal</ref>
Local people in Nepal attributed various mystical powers to the ghara of male gharials and killed them to collect their snouts.<ref>Template:Cite book</ref> 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.<ref name="maskey94"/> Jewellery found in gharial stomachs may have been the reason for the belief of local people that they would eat humans.<ref name=Whitaker1982/>
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.<ref name=Daniel1983/>
See alsoEdit
ReferencesEdit
External linksEdit
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