Gharial

• 1. Introduction

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  The gharial is a fish-eating crocodilian from the rivers of the northern Indian subcontinent, and its numbers have collapsed within living memory. In 1946 the wild population was estimated at between 5,000 and 10,000 animals. By 2006 fewer than 250 individuals remained. That is a decline of 96 to 98 percent within three generations. Since 2007 the IUCN Red List has classed the species as critically endangered. What kind of animal is this, among the longest of all living crocodilians, with a face built almost entirely for catching fish? Why do adult males grow a hollow knob on the end of the snout? How did a species that once filled the great rivers of the north come so close to vanishing? And why has releasing captive-bred animals failed to repair the damage?

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• 2. The Ghara

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  An earthen pot gave the gharial its name. The Hindustani word ghara means exactly that, and the hollow bulb on an adult male's snout looks much like one. Females and young males do not have it. The bulb starts to grow over the nostrils when a male is 11.5 years old. By the age of 15.5 years it measures about 5 by 6 by 3.5 centimetres. Males become sexually mature at 15 to 18 years, when they reach roughly 4 metres in length and the ghara is fully formed.

  With the ghara, a male can make a hissing sound that carries 75 metres. The sound is thought to attract females. Researchers have also suggested that the bulb works as a resonator when a male bubbles underwater, or simply signals that he is mature. No other living crocodilian shows such visible differences between the sexes.

  Bengal supplied another name. The Bengali mecho kumhir joins mach, meaning fish, with kumhir, meaning crocodile, and it gives English the label fish-eating crocodile. The alternative spelling gavial comes from the same root as gharial.

  Size also separates the sexes. Mature females measure 2.6 to 4.5 metres, while males reach 3 to 6 metres. The average adult male weighs about 160 kilograms, and large males can reach 600 to 750 kilograms. The heaviest male on record weighed 977 kilograms.

  Larger claims exist, but none is reliable. A gharial of 6.55 metres was said to have been killed in the Ghaghara River at Faizabad in August 1920, yet nobody took trustworthy measurements. Males alleged to be between 7.16 and 9.14 metres long were reported in Indian rivers around the turn of the 20th century.

  Length does not translate into bulk. A gharial of 4.9 metres weighed about 560 kilograms, while a Nile crocodile of 4.8 metres weighed 680 kilograms. The gharial is slimmer than its relatives, and that slimness belongs to a body designed for fishing.

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• 3. Built For Fish

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  A gharial's jaws hold about 110 sharp, interlocking teeth. Each side of the upper jaw carries 27 to 29 of them, and each side of the lower jaw carries 25 or 26. The front teeth are the largest. The first three lower teeth slot into gaps in the upper jaw, so the two rows mesh like a trap.

  The snout of an adult is 3.5 times longer than the width at the base of the skull. It is narrow and widens at the tip. The fused section of the lower jaw runs back as far as the 23rd or 24th tooth. Such a snout meets little resistance in the water, which suits an animal that hunts fish underwater.

  The animal does not chew. It swallows prey whole. Young gharials have been seen jerking their heads back to shift a fish around, then sliding it into the gullet head first. Larger fish are torn apart before swallowing.

  The menu changes with age. Young gharials eat insects, tadpoles, small fish and frogs. Adults add small crustaceans, and the remains of an Indian softshell turtle have been found in stomachs.

  The colour shifts too. Young gharials are olive with dark brown cross bands and speckles. Adults are darker, and the back turns almost black by the age of 20 years. The belly stays yellowish-white. The fingers and toes are partly webbed.

  Gharials also pick up stones and swallow them. These gastroliths probably aid digestion or help regulate buoyancy. A gharial shot in the Sharda River in 1910 carried stones weighing about 10 pounds. Stones were not the only objects found inside these animals, and the other discoveries fed a belief that surrounds the species.

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• 4. Naming And Ancestry

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  In 1789 the German naturalist Johann Friedrich Gmelin gave the gharial its first scientific name, Lacerta gangetica. He was following Carl Linnaeus, who had created the genus Lacerta in 1758 to hold crocodiles alongside various lizards. Later naturalists moved the animal into the genus Crocodilus and kept renaming it. Pierre Joseph Bonnaterre called it Crocodilus gavial in 1789, Johann Gottlob Theaenus Schneider used Crocodilus longirostris in 1801, and Francois Marie Daudin chose Crocodilus arctirostris in 1802.

  Georges Cuvier grouped long-snouted crocodiles as Longirostres in 1807. Nicolaus Michael Oppel introduced the genus name Gavialis in 1811, and Johann Georg Wagler proposed Rhamphostoma in 1830 for two species. Arthur Adams created the family Gavialidae in 1854. Albert Gunther treated the animal as a single species in 1864.

  John Edward Gray reviewed specimens at the Natural History Museum in London and reached the same view in 1869. He placed the gharial in Gavialidae beside the false gharial, Tomistoma schlegelii, because both have long, slender jaws and similar teeth. In 1886 Richard Lydekker named Gharialis hysudricus from an unusually large fossil skull in the Sivalik Hills. That name is now treated as a junior synonym.

  How the gharial relates to other crocodilians has long been disputed. Some authors argued that it branched off first, because its skull and teeth are so specialised. Others argued that it branched off much later, because its blood proteins have diverged so little. Its tail muscles are unique, which led to a third proposal that the gharial and all other crocodilians are sister groups.

  Genetics has narrowed the dispute. A ribosomal segment of mitochondrial DNA in the gharial and false gharial shares 22 unique nucleotides, a similarity of 94 percent. Nuclear genes agree that the two are sister taxa. Their lineages split in the Eocene.

  Fossils trace the genus through Asia. Gavialis probably originated in the region of India and Pakistan in the Early Miocene. Remains from the Sivalik Hills of Haryana and Himachal Pradesh date from the Pliocene to the Early Pleistocene. Two sites in the Ayeyarwady River valley of central Myanmar yielded remains from the Late Pleistocene.

  The genus reached as far as Java by the Siva-Malayan route, which required no crossing of salt water. Gavialis bengawanicus fossils from Java date to the Early Pleistocene. Others from Nakhon Ratchasima Province in Thailand support the idea that gharials spread through river systems. It is the only valid extinct species of Gavialis. Later, people along the same rivers left their own records of the animal, in stone and on clay.

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• 5. Gods And Remedies

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  Seals and tablets from Mohenjo-daro and Amri in Sindh show gharials with fish in their mouths and fish swimming around them. They are about 4,000 years old and are the earliest known depictions of the species. One tablet shows a deity flanked by a gharial and a fish.

  A gharial also appears among the rock carvings on a pillar of the Sanchi Stupa, which dates to the 3rd century BC. In Hindu mythology the animal serves as the vehicle of the river deity Ganga. It also carries Varuna, the deity of wind and sea.

  The 16th-century Baburnama records a sighting by its author, Zahir-ud-din Muhammad Babur. In 1526 he noted a gharial in the Ghaghara River between Ghazipur and Benares.

  By 1915, hunting it had its own craft. A British officer watched Kehal fishermen along the Indus stake nets beneath the waterline beside a sandbank and then hide. When gharials came out to bask, the fishermen emerged from cover. The startled animals bolted for the river and tangled themselves in the nets.

  People living near the rivers credited the animal with mystical and healing powers, and some body parts went into indigenous medicine. In Nepal, men killed male gharials to collect their snouts because of beliefs about the ghara. The Tharu people held that a burnt ghara would repel insects and pests from a field. They also considered gharial eggs an effective cough medicine and an aphrodisiac.

  The jewellery sometimes found inside gharial stomachs may explain a darker belief, that the animals eat humans.

  Local names show how widely the animal is known. Nepali speakers say Lamthore gohi and Chimpta gohi, where gohi means crocodile. Marathi speakers say Susar, and Bihari speakers say Nakar or Bahsoolia nakar. In Odia the species is Thantia kumhira, and thantia comes from the Sanskrit tunda, meaning beak, snout or elephant's trunk. The Odia also call the male Ghadiala and the female Thantiana.

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• 6. Sandbank Life

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  Every December and January, young, subadult and adult gharials gather in large groups to bask on riverbanks. Basking matters because the animal is cold-blooded. It must warm up when the air is cool and cool down when the heat rises. Gharials prefer sandy, moist beaches, and they bask daily in the cold season, mostly in the mornings.

  As days grow warmer, the pattern shifts. They start basking earlier, slip back into the river during the heat, and return to the beach later in the afternoon. A typical group has an adult male, several females and subadults. The adult male dominates and tolerates immature males.

  The mugger crocodile shares parts of the gharial's habitat and its nesting grounds. The two differ in where they bask. The gharial stays close to water on shallow, sandy beaches. The mugger climbs steep embankments and rocks and ranges farther from the beach. It also eats snakes, turtles, birds, mammals and carrion, while the gharial sticks to a narrower diet.

  Adult males and females come together by mid-February, and courtship and mating begin. In the dry season, reproductive females on the Chambal River routinely travel 80 to 120 kilometres to join breeding groups. There they dig nests together on riverside sand or silt banks, 2.5 to 14.5 metres from the water. Females have been seen digging trial nests first.

  Between the end of March and early April, each female lays 20 to 95 eggs. A record clutch of 97 eggs was found in Katarniaghat Wildlife Sanctuary. The eggs are the largest of any crocodilian and average 160 grams. After 71 to 93 days of incubation, the young hatch in July, just before the monsoon. Temperature most likely determines their sex.

  Mothers dig out hatchlings in response to their chirps but do not help them reach the water. The females stay at the nesting site until monsoon floods arrive and return after the rains. Fatherhood varies. Captive males observed in the 1980s did not guard nests, though one allowed hatchlings to ride on his back. On the Chambal, radio tracking showed that a junior male guarded a communal nesting site as the dominant male for two years.

  Young gharials spend their first year hiding and foraging in shallow water, often among debris from fallen trees. A study along 425 kilometres of the Chambal found that older animals favour deeper water. Subadults and adults longer than 180 centimetres prefer sites deeper than 4 metres.

  Hatchlings move by pushing diagonally opposite legs together. They can gallop, but only in emergencies. At 8 to 9 months, when they reach about 75 centimetres and 1.5 kilograms, they switch to the adult gait of pushing with hind and front legs at once. Adults cannot walk in the semi-upright stance that other crocodilians use, and on the beach they often turn around to face the water.

  Open riverbanks at potential nesting sites are crucial to reproductive success, and the next chapter follows what happened to the rivers.

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• 7. Vanishing Rivers

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  In the early 20th century, the gharial was considered common in the Indus River and its Punjabi tributaries. By the early 1980s it was almost extinct there. Surveys in 2008 and 2009 did not sight a single gharial in the river. The species once thrived in every major river system of the northern subcontinent, from the Indus and Ganges to the Brahmaputra and the Irrawaddy in Myanmar.

  One river after another lost its gharials. Hunting wiped them out of the Godavari between the late 1940s and the 1960s. The Koshi River was considered empty of them from 1970. In the 1940s the Barak River in Assam was full of gharials and big fish, including golden mahseer. A few animals were seen in its tributaries up to 1988, though no surveys followed.

  In Myanmar, a gharial shot in the Shweli River in 1927 is the only authenticated record of survival into the 20th century. The species is locally extinct in Bhutan and Myanmar. By 1976 the range had shrunk to 2 percent of its historical extent, and fewer than 200 gharials were estimated to survive.

  People caused the first losses. Fishermen killed gharials, hunters took skins and trophies, and others gathered eggs to eat or took animals for indigenous medicine. Hunting is no longer considered a significant threat. The wild adult population still fell from an estimated 436 in 1997 to fewer than 250 in 2006.

  Gill nets used for fishing are one cause. The other is the loss of riverine habitat. Dams, barrages, irrigation canals and artificial embankments were built, siltation and sand mining changed river courses, and the land beside rivers was given over to farming and livestock grazing.

  On the upper Brahmaputra, fewer than 20 individuals were sighted between Kaziranga National Park and Dibru-Saikhowa National Park from 1979 to 1993. Commercial fishing, poaching, encroachment on breeding grounds and siltation after deforestation had hollowed out that population. In 1998 it was not considered viable.

  In the Karnali River, unprotected stretches face boulder quarrying, sand mining and unlicensed fishing. On the Chambal, water pumps that draw water from the river harm gharials too.

  The Chambal also produced the most alarming episode. Between December 2007 and March 2008, 111 dead gharials were found there. Toxicants or illegal fishing nets were suspected at first. Post mortem tests showed high levels of lead and cadmium, together with stomach ulcers and protozoan parasites in most animals, and these were thought to have caused the deaths. Yet the same river would later hold the species' strongest population.

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• 8. Rescue By Release

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  In 1975 the Indian Crocodile Conservation Project began in Odisha's Satkosia Gorge Sanctuary, under the auspices of the Government of India. The United Nations Development Fund and the Food and Agriculture Organization paid for it. The country's first gharial breeding center opened in Nandankanan Zoological Park, and a male flown in from Frankfurt Zoological Garden became one of the founding animals.

  In 1976 two more breeding centres opened in Uttar Pradesh, at Kukrail Reserve Forest and Katarniaghat Wildlife Sanctuary. Each could hatch and raise up to 800 gharials a year. Between 1975 and 1982 the country established sixteen crocodile rehabilitation centers and five crocodile sanctuaries. Eggs were first bought from Nepal. The method was simple: incubate the eggs, raise the young for two to three years, and release them at about one metre in length.

  India protects the gharial under the Wildlife Protection Act of 1972, and Nepal does so under its National Parks and Wildlife Conservation Act of 1973. The species is also listed on CITES Appendix I.

  Nepal ran its own program. Since 1978 the Gharial Conservation and Breeding Center in Chitwan National Park has incubated wild eggs gathered along rivers. The first batch of 50 gharials went into the Narayani River in spring 1981. By 2016 the center was overcrowded with more than 600 gharials aged 5 to 12 years, and many were too old to release. Between 1981 and 2018, 1,365 gharials were released into the Rapti-Narayani river system.

  India released more than 5,000 gharials between the early 1980s and 2006. Yet in 1991 the Ministry of Environment and Forests withdrew funds for captive breeding and egg collection, arguing that the project had served its purpose.

  The results were uneven. The National Chambal Sanctuary did well. It held 107 gharials in 1974, and 1,095 in 1992. By 2019 it held 1857 individuals, including 1116 adults, and 486 nests were recorded.

  Elsewhere the releases barely registered. About 700 gharials were released into the Mahanadi between 1977 and the early 1990s, but a survey in 2005 and 2006 found only one male and one female. A total of 142 went into the Ken River between 1982 and 2007, and only one adult female was seen in 2013. Of 36 marked gharials released into the Rapti-Narayani rivers in 2002 and 2003, only 14 were alive in spring 2004.

  A 2017 critique called the program uncoordinated. It said releases often involved animals that were too old and of unknown sex, set free at disturbed sites in the unfavourable cold months, without checking whether the releases worked. The critics suggested leaving wild nests in place, protecting nesting and basking sites more strongly, and tracking gharial movements. Members of the Crocodile Specialist Group added that local communities should join the effort.

  One local intervention has paid off. On the Girwa River in 2019, workers cleared woody vegetation from sand banks and mid-river islands. In 2020 they added sand to build an artificial bank of about 1000 square metres. Nests rose to 36 in 2020 from 25 in 2018, and unhatched eggs and dead hatchlings dropped sharply.

  In May 2023, gharials were reported in the Punjab region of Pakistan, the first confirmed sighting in the country after a presumed absence of three decades. A 70 kilometre strip of the Sutlej River was notified as the Gharial Wildlife Sanctuary in July 2023. WWF-Pakistan and its partners aim to help the newly found population thrive, and Pakistan has asked Nepal to transfer hundreds of gharials.

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