Gharials

The Gharial (Gavialis gangeticus), also known as the fish-eating crocodile, is a crocodile in the Gavialidae family and among the longest of all living crocodilians. 

Mature females are 2.6–4.5 m  long and males 3–6 m. Adult males have a distinct boss at the end of the snout, which resembles a clay pot known as gara, hence the name "Gharial". The Gharial is well-suited for hunting fish because of its long, narrow nose and 110 sharp, interlocking teeth. 

 

The Gharial probably evolved in the northern Indian subcontinent. Fossils of gharials have been discovered in Pliocene deposits in the Sivalik Hills and Narmada Valley. It now lives in the rivers of the plains of the northern part of the Indian subcontinent. It is the most thoroughly  Aquatic crocodilian, and leaves water only for basking and building nest near wet sand.

Adults mate at the end of winter. Females gather in the spring to build nests, in which they lay 20 to 95 eggs. They protect the nest and the young before the monsoon starts. 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 significantly since the 1930s to only 2% of its historical range. Conservation programs developed in India and Nepal have focused on reintroducing Captive bred gharials since the 1980s. Habitat loss due to sand mining and conversion to agriculture, depletion of fish stocks and destructive fishing methods continue to threaten the population. 

 

It has been classified as ‘’Critically Endangered’’ on the IUCN Red List since 2007. The oldest known depiction of a Gharial dates back to about 4,000 years ago and was found in the Indus Valley. Hindus consider it as the vehicle of the river god Ganga. Villagers living near the river claim that the Gharial has mystical and healing powers and its body parts are used as ingredients in indigenous medicine.

Gharials are olive-colored, with adults darker than young, which have cross bands and speckles. Its back becomes almost black at the age of 20, but its belly is yellowish-white. It has four transverse rows of two scales on the neck, which continue along the back. The scutes on the head, neck and back form a continuous plate with 21-22 transverse processes and four longitudinal processes. The scutes on the back are bony, but soft and weak on the sides. On the outer edges of the arms, legs, and feet there are protruding ridges, Fingers and toes partially webbed.

 

The snout is very long and narrow, widened at the end, 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 teeth of the lower jaw fit into the socket of the upper jaw. The snout of adults are 3.5 times longer than the width of the skull base. Because of this long snout, the Gharial is best at catching and eating fish. The Gharial has a tensile strength ( bite force) of 1,784–2,006 N (401–451 lbf).

 

Reproductive males develop a nasal cavity at the end of the nose when they reach maturity. This display is similar to a clay pot known locally as "ghara". A males ghara begins to grow over the nostrils at the age of 11.5 years and measures approximately 5 cm × 6 cm × 3.5 cm at the age of 15.5 years. It allows males to emit a hissing sound that can be heard 75 m (246 ft.) away. The Gharial is the only living crocodile with such visible dimorphism.

 

Females reach maturity at a body length of 2.6 m  and grow to 4.5 m. Males grow to a body length of at least 3 m  and reach a length of 6 m (20 ft.). Adult males weigh about 160 kilograms (350 lb.) on average. Mature males have larger skulls than females, exceeding a basal length of 715 mm (28.1 in) and a width of 287 mm (11.3 in).

The Gharial once flourished  in all water systems in northern India, from the Indus River in Pakistan, the Ganges in India, the Brahmaputra River in northeastern India, and from Bangladesh to the Irrawaddy River in Myanmar. In the early 20th century, it was considered common in the Indus River and its Punjab region. By the early 1980s it had almost disappeared from the Indus. During surveys in 2008 and 2009, no Gharials were found in the river. It also occurs in the Godavari River in India, but was driven to extinction between the late 1940s and 1960s.

 

It has been considered extinct in the Koshi River since the 1970s. In the 1940s, it was abundant in the Barak River in Assam, which at the time contained large fish including the golden mahseer (Tor putitora). A few were also found in Barak river in Assam, Mizoram and Manipur until 1988, but no research was done. In 1927, a young female was shot dead in Myanmar's Shweli River. This is the only systematic record in the country that testifies to the survival of gharials in the 20th century. It is possible that gharials still live in Shweli River today, but this is not clear as of 2012.

 

 

It is extinct in Pakistan, Bhutan and Myanmar. Since the early 1980s, captive populations have been boosted in wild habitats in India and Nepal. In 2017, the global population is estimated to be about 900 people, including about 600 adults in six areas along 1,100 km (680 mi) of waterways.

 

In Nepal, small populations are now present and slowly recovering in areas of the Ganges, such as the Karnali-Babai river system in Bardia National Park, and the Narayani-Rapti river system in Chitwan National Park.  In the spring of 2017, the Babai River was surveyed using an unmanned aerial vehicle, which detected 33 Gharials over a 102 km (63 mi) stretch.

 

 

The ‘Ramganga River in Corbett National Park’, where five gharials were recorded in 1974. The Gharials have been released in captivity since the late 1970s. The population has been growing since 2008 and reached about 42 adults in 2013. Most of them are clustered along the 8 km (5.0 mi) long stretch of ‘Kalagarh Basin’. A 2015 survey showed a population of 90 gharials including 59 breeding adults.

 

Ganges, where 494 gharials were released between 2009 and 2012 into the ‘Hastinapur Wildlife Sanctuary’.

 

The Girwa River in the ‘Katarniaghat Wildlife Sanctuary’ has been a breeding ground for small herds since 1979. A total of 909 gharials were released by 2006, but only 16 females were recorded that year. In December 2008, 105 individuals including 35 adults were counted. In spring 2009, 27 nests were found at seven sites. The number of nest sites decreased from seven in 2017 to two in 2019, possibly due to vegetation growth and reduced water flow along the sand bank.

 

The ‘Gandaki River’ downstream from the Triveni Dam west of the ‘’Valmiki Tiger Reserve’’ and near the ‘Sohagi Barwa sanctuary’. The population has increased from 15 gharials in 2010 to 54 individuals recorded in March 2015 over a length of 320 km (200 mi). Thirty-five of these people were wild born.

 

The ‘Chambal River’ is located in the Chambal National Sanctuary where 107 gharials were recorded in 1974. Gharials have been released in captivity since 1979, and the population rose to 1,095 gharials in 1992. Between December 2007 and March 2008, 111 gharials were found dead. A total of 948 gharials were counted during surveys in 2013 along the reserve's 414 km (257 mi) stretch of river. In 2017, these figures were estimated at 617-761 mature individuals and more than 1250  from two different research groups; 411 nests were found.

 

Also, found in Parbati river, tributary of Chambal, Yamuna, son, koshi ( first record of wild gharials in the river since 1970’s), Mahanadi river, Brahmaputra river.
In Bangladesh, gharials were recorded in Padma, Jamuna, Mahananda and Brahmaputra rivers between 2000 and 2015.

Young gharials eat insects, tadpoles, small fish and frogs. Adults also eat small crustaceans. The ‘Indian softshell turtle’ (Nilssonia gangetica) is also found in the gharial stomach. Gharials tear apart large fish and pick up and swallow stones such as gastroliths, perhaps to aid digestion.  Some gharials stomach contain jewellery. Stones weighing  about 4.5 kilograms (10 lb.)   was found in Gharial stomach which was shot dead in the Sharda River in 1910.

Females reach maturity at a body length of about 2.6 m (8 ft 6 in). Females in captivity grow to a body length of 3 m. Young males grow between the ages of 15 and 18, when they reach a body length of about 4 m (13 ft.). The ghara apparently used to show sexual maturity, such as the sound that makes when bubbling underwater, or for other sexual behaviours.

 

Mating begins between February at the end of winter. During the dry season, female spawners found in the Chambal River often travel 80–120 km (50–75 mi) and join swarms of female spawners to build nests. They prefer sites near river sand or silt between 2.5 and 14.5 m from the water and above the water level from 1 to 3.5 m.

 

These nests are 20-55 cm deep and about 50-60 cm in diameter. Between late March and early April, they lay between 20 and 95 eggs. A record holding of 97 eggs was found at the ‘Katarniaghat Sanctuary’. Eggs are the largest of all crocodiles and weigh about 160 g (5.6 oz.). Each egg is 85–90 mm (3.3–3.5 in) long and 65–70 mm (2.6–2.8 in) wide. After 71 to 93 days of incubation, young females emerge in July just before the onset of monsoon. Their sex is likely determined by temperature, as is the case with many reptiles. They stay in the nesting area until the monsoons arrive and return after the monsoons.

 

Captive males found in the 1980s did not participate in nest conservation. A male gharial in captivity was seen showing hatchlings and  female allowed him to carry the baby on her back. In the Chambal river, females are seen staying near the nest sites and protecting the young  until the flood is over. VHF radio tracking of the  junior male gharial  will show that he has been the dominant male guarding the nest for two years.

 

The Gharial population is estimated to have declined from 5,000–10,000 individuals in 1946 to less than 250 individuals in 2006, a 96–98% decline over three generations. Gharials were killed by fishermen, hunting for skins, trophies and local medicine, and their eggs were collected for consumption. The rest form many fragmented communities. Poaching is not considered a serious threat.

 

However, the wild population has declined from around 436 adults in 1997 to less than 250 adults in 2006. One of the reasons for this decline is the proliferation of gillnets for fishing in Gharial habitat. Another major cause is the loss of riverine habitat due to the construction of dams, wells, canals and artificial barriers; siltation and sand mining has changed the course of the river; and the land near the river is used for agriculture and livestock.

 

 

When 111 gharials were found dead in the Chambal River between December 2007 and March 2008, it was initially suspected that they had died from poison or entangled fishing nets. Post-mortem examinations of the bodies revealed high levels of heavy metals such as lead and cadmium, which, along with stomach ulcers and protozoan parasites reported in several post-mortem studies, and are believed to have caused their deaths. It has been found that pumping of water from the Chambal water are harmful to the Gharials.

 

Threats to the unprotected area of the Karnali River include quarrying, sand mining, and unlicensed fishing.

Preservation:

Listed in ‘Appendix I of CITES’. In India, it is protected by the Wildlife Protection Act 1972. In Nepal, it is protected under the National Wildlife Conservation Act of 1973.

Since the late 1970s, conservation efforts have focused primarily on reintroduction. The rivers in protected areas in India and Nepal are used to be restocked with captive bred juveniles Gharials. Gharial eggs are hatched, incubated and young gharials are raised for two or three years and released when they are about one meter long.

 

In 1975, the ‘Indian Crocodile Conservation Project’ was established under the auspices of the Government of India, initially at the ‘Satkosia Gorge Sanctuary’ in Odisha. It was made possible with financial assistance from the ‘United Nations Development Fund’ and the ‘Food and Agriculture Organi.