Indian Gharial: Interesting facts | TechGape

Save the Highly Threatened Gharials 

-Dr. Arvind Singh 

Gharial also known as ‘gavial’ and the ‘fish-eating crocodile’ is a species of reptile found in fresh water and is native of the Indian sub-continent. The name Gharial comes from the bulbous nasal appendage of the adult male, which resembles an Indian pot ghara. The scientific name of Gharial is Gavialis gangeticus which belongs to the Gavialidae Family of Order Crocodilia. It is the only survivor of the family.

Gharials are survivors from great reptilian age and are ecologically important organisms. They are recognized as keystone species in their environment. Keystone species are those which maintain the structure and organization of the community. 

In Indian mythology, Gharial is revered as the vehicle of Ganga (River Deity) and Varuna (God of winds). Traditionally the animal has been identified with water, the source of all existence and fertility. It is the insignia of Kamadeva God representing love and lust and Kama’s flag (dhwaja) is known as Karkadhvaja i.e. Gharial depicted on the flag. 

The extremely fragmented distribution, deteriorating status and intense pressure from human activities makes Gharial as one of the highly-threatened animal species on the planet. It has been listed as “Critically Endangered” in the Red List of Threatened Species of International Union for Conservation of Nature and Natural Resources (IUCN). Critically endangered species are those which are facing the immediate threat of extinction. 

Distribution Range:

Gharials once lived in all the major river systems of the Indian sub-continent, spanning the rivers of its northern part from the Indus River in Pakistan across the Gangetic flood plain to the Irrawaddy River in Myanmar. However, today they are extinct in the Indus River, in the Brahmaputra of Bhutan and Bangladesh, and in the Irrawaddy River of Myanmar. The distribution of Gharials is now limited to only 2% of their former range. 

In India, small populations are present in the rivers of National Chambal Sanctuary, Katarniaghat Wildlife Sanctuary, Sone River Sanctuary and the rainforest biome of Mahanadi in Satkosia Gorge Sanctuary, Odisha. 

In Nepal, small populations are present in tributaries of the Ganges, such as the Narayani-Rapti river systems in Chitwan National Park and the Karnali-Babai river system in Bardia National Park.

Physical Features:

The Gharial is one of the largest of all crocodilian species characterized by their extremely long, thin jaws, regarded as an adaptation to a predominantly fish diet. The gharial is dark or light olive above with dark cross-bands and speckling on the head, body, and tail. Dorsal surfaces become dark, almost grey-black at about 20 years of age. Ventrals are yellowish-white. The neck is elongated and thick. The fingers are extremely short and thickly emarginated with a web.

The size of mature Gharials ranges between 3.5 to 4.5 m. The maximum reported size is 6.25 m. Young Gharials can reach a length of 1m in 18 months. The average body weight varies between 159-250 kg. Males attain a total length of 3 to 5 m whereas females are smaller and reach a body length of up to 2.7 to 3.75 m. 

The elongated narrow snout of Gharials is lined by 110 sharp interdigitated teeth and becomes proportionally shorter and thicker as the age of animal advances. There are 27 to 29 upper and about 25 lower teeth on each side.

The bulbous growth on the tip of male’s snout is called as “Ghara”, and is present in mature individuals. It serves as a vocal resonator and as a visual signal to females.

Habitat and Ecology:

Gharials generally prefer flowing rivers with deep pools that have high sand banks and good fish stocks. In fact, they are more adapted to an aquatic lifestyle in the calmer areas of deep.

The Gharials are poorly equipped for locomotion on land, and adults cannot lift their bodies clear on the ground and its leg musculature is not suited to raise the body off the ground or to produce the “high walk” gait. It is able only to push its body forward across the ground or “belly-side”. It is, however, very agile in the water. It usually only leaves the water to bask and nest, both of which usually occur on sandbanks.

The thin shape gives the snout low resistance in the water, which is suited to fast lateral snatching movements underwater. The diet changes as the Gharial matures from a juvenile to an adult. The juveniles feed insects, tadpoles, small fish and frogs while adults feed on fish for which their jaws and teeth are perfectly adapted. They do not chew their prey but swallow as a whole.

Males attain sexual maturity at around 13 years of age. They advertise for mates by making hissing and buzzing noises as they patrol their territories and may have a harem of females within a territory which they aggressively defend from other males. Females communicate their readiness to mate by raising their snouts upwards. Courtship involves head and snout rubbing and mounting by both males and females.

Mating occurs in cold season (December and January). In India, Gharials nests in March and April during the dry, low water season. Gharials are hole nesters and excavate a 50-60 cm deep egg chamber with their hind feet into the sandy banks above the flood line (1.5 m from the waterline). Females lays 20-95 eggs into the hole before it is covered over carefully. The eggs are large in size with an average weight of 160 gm. They are incubated naturally. After 71-93 days of incubation, young Gharials hatch in month of July just before the monsoon. Temperature is supposed to play a crucial role in determining the gender.

Threats to Survival:

The Gharial endemic to Indian sub-continent was once abundant and common with an estimated population of 5,000 to 10,000 in 1940. The Gharial came incredibly close to extinction in 1970s but a long term captive breeding and re-introduction program was instrumental in improving the species status in the wild over the following decades.

Despite these efforts between 1997 and 2006, the wild population declined by 58% from 436 to just 182 breeding adults. The total wild population of Gharial in the world is now estimated to be less than 200 individuals. The decline in the Gharial populations have been linked to a decline in fish catches as predatory fish of no interest to the fishermen, form a major part of the Gharial diet.

The main threats to the survival of Gharials include habitat loss, hunting, fishing, turtle poaching, river water pollution, egg collection for consumption, killing for indigenous medicines and killing by fishermen.

The loss of habitat due to the construction of dams, barrages, irrigation canals, siltation, sand-mining, riparian agriculture, and livestock grazing is the main cause behind the drastic decline in the population of Gharials. Throughout all of the present range of the Gharial the rivers have been dammed and diverted for irrigation and other purposes leading to seasonal drying thus making the habitat inhospitable for Gharials especially during the dry season. Large scale sand mining destroys the sand banks required for Gharials for nesting and basking thus causing disruption to nesting and basking behavior. Increasing riparian agriculture is a widespread problem throughout the Gharial range areas. As the river recedes agriculture advances on the river banks further limiting the few nesting and basking areas available for Gharials.

The increase in the intensity of fishing and the use of gillnets which kills adults and sub-adults is another threat prevalent throughout most of the Gharial habitat even in protected areas. Gharials are also caught and killed in long lines of hooks set for turtle poaching.

Chambal River, the last strongholds of Gharials is under particular threat from fishing, turtle poaching and sand mining which are carried out by organized armed groups, making enforcement and even research activities difficult and dangerous. 

Hunting of Gharials for skins and trophies is also a threat to Gharials. The eggs of Gharial are occasionally collected by local people for medicinal purposes have also been a threat to Gharials.

The river water pollution is also a threat to the survival of Gharials. In December 2007, several Gharials were found dead in the Chambal River. Post mortem of Gharials revealed high levels of heavy metals like lead and cadmium in their stomach to have caused their deaths.

Gharials are killed for their aphrodisiac properties associated with the snout. Gharials are also snared in fishing nets and killed by the fishermen.

Conservation:

The gharial is listed in Appendix I in the Convention on International Trade in Endangered Species (CITES and is protected under the Indian Wildlife (Protection) Act, 1972.

Gharials are bred in captivity in the National Chambal Sanctuary in Uttar Pradesh, India and in the Gharial Breeding Centre at Chitwan National Park in Nepal. They are generally grown for 2-3 years and average about 1 meter when released.

The Gharial Conservation Alliance (GCA) was established in 2007 and comprises of key Gharial scientists, experts, and stakeholders primarily in Gharial range states. It is coordinating research and conservation activities on the remaining population and habitats.

The following actions are needed for the conservation of Gharials in India.

1. To check the habitat loss of Gharials. 

2. To strictly enforce the Indian Wildlife (Protection) Act and CITES. 
3. To put a complete ban on fishing in the areas inhabited by Gharials. 
4. To ensure the availability of sufficient foods in the habitats of Gharials. 
5. To check the river water pollution. 
6. To involve local people in the conservation of Gharials.

Conclusion:

It can be concluded that the population of Gharials has shrunk to a serious extent due to habitat loss, hunting, fishing, turtle poaching, river water pollution, egg collection for consumption, killing for indigenous medicines and killing by fishermen. Thus this ecologically important species of reptiles face the threat of extinction. Therefore, it is the need of the hour to save the Gharials for the maintenance of biological diversity and ecological stability of the river ecosystem.

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Dr. Arvind Singh is M. Sc. and Ph. D. in Botany with an area of specialization in Ecology. He is an dedicated Researcher having more than four dozen of published Research Papers in the Journals of National and International repute. His main area of Research is Restoration of Mined Lands. However, he has also conducted research on the Vascular Flora of Banaras Hindu University-Main Campus, India.

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