Gavialis gangeticus

Common names: Gharial, gavial Range: Bangladesh (extinct), Bhutan (extinct?), India, Myanmar (extinct?), Nepal, Pakistan

CITES: Appendix I
CSG Action Plan: Availability of Survey Data – Adequate
Need for Wild Population Recovery – Highest
Potential for Sustainable Management – Low
1996 IUCN Red List: EN Endangered. Criteria C.2.a. population < 2,500 and severely fragmented. Population and Habitat Viability Analysis 1995.
Principal threats: Habitat destruction, limited distribution.

Ecology and natural history

The gharial is the most long-snouted and together with the saltwater crocodile the largest of the living crocodilians (males up to 6–7m). Placed in a family by itself, the Gavialidae, the gharial has long been separated from the rest of the crocodilian stock, with the possible exception of Tomistoma (Densmore 1983). Gharial are arguably the most thoroughly aquatic of the extant crocodilians, and adults apparently do not have the ability to walk in a semi-upright stance as other crocodilians do (Bustard and Singh 1978). Adult males grow a bulbous nasal appendage, which resembles an Indian pot called a ‘ghara,’ from which the species derives its name. Gharial are restricted to the northern part of the Indian subcontinent where they were found in four river systems: the Indus (Pakistan), the Ganges (India and Nepal), the Mahanadi (India) and the Brahmaputra (Bangladesh, India and Bhutan). The presence of the species in the Kaladan and Irrawaddy Rivers in Burma has also been reported (Smith 1931).

The gharial is typically a resident of deep, fast flowing rivers, but within these rivers prefers areas where the current is reduced (Whitaker and Basu 1983). Exposed sand banks are used for nesting. Although the function of the ghara is not well understood, it is apparently used as a visual sex indicator, as a sound resonator, or for bubbling or other associated sexual behaviors (Martin and Bellairs 1977).

The gharial appears to be primarily a fish-eating species, but very large individuals are known to eat other prey. Females may not reach sexual maturity until they are nearly 3m long. Nesting is done during the annual dry season in holes excavated in river sand banks (Whitaker and Basu 1983). Unlike most other crocodilians who carry their young from the nest in the mouth, gharial appear not to do this because of the unusual morphology of their jaws (Singh and Bustard 1977). However, post-natal maternal care has been observed. Female gharial typically lay 30–50 eggs, and the eggs are the largest of any crocodilian (average 160g).

Male gharial, Gavialis gangeticus, showing the swollen structure at the snout tip
(ghara = pot) for which the species is named. Photo by H. Andrews.

Conservation and status

The gharial is one of the most Endangered of the crocodilians. However, unlike the other seven most endangered crocodilians, good conservation programs are now in place over much of the species range. The species was literally brought back from the brink of extinction by restocking programs initiated first in India in 1975, and in Nepal in 1978. In India, a total of nine protected areas with an area of nearly 3,000km² (along the Ganges and its tributaries and at Satkoshia Gorge on the Mahanadi) have been designated for gharial management (Rao and Singh 1994). Gharial are captive bred for release at six breeding centers and eggs are also collected from wild nests for captive raising and release. Over 3,000 juveniles have been released at 12 sites. The major release sites are the Chambal river (1,718 released 1979–1993), Ramganga river (257 released 1982–1994), Girwa river (172 released 1979–1994) and the Sharada river (105 released 1986–1992), all in the Ganges drainage, and in the Mahanadi river in Orissa (609 released 1977–1989). Follow-up surveys suggest an overall increase in the total wild population which has levelled off since 1990 as the number of available sites have become filled. Current wild population is estimated to be in excess of 1,500 individuals (Anon. 1993b), of which more than 1,000 are found in the Chambal river with around 64 nests a year at 15 different sites (Rao and Singh 1994). At several other areas and sites of smaller releases, such as the Satkoshia Gorge (Mahanadi River) and Ken and Son rivers, the restocking program has not resulted in population increases although some gharial remain. Increasing problems have been experienced with the high cost of captive breeding and the paucity of additional sites for the release of gharial. Increasing interactions between riverside human populations and gharials, as well as the negative effects of agriculture and fishing, restrict successful gharial populations to a few stretches of isolated and protected rivers. Increasing or even maintaining the program is problematic at present. A Population and Habitat Viability Analysis (PHVA) was conducted in early 1995 to plan future strategies (Rao et al. 1995). Population modelling under different assumptions suggested that the Chambal population may be self-sustaining but smaller populations in the Mahanadi and other localities require continued replenishment. Major recommendations derived from this analysis were the preparation of a National Management Plan, continuous monitoring of protected and restocked populations, an analysis of genetic diversity and the effects of a bottleneck in the founder stock, increased public education and the continuation of restocking. Migration out of protected areas was identified as a significant factor slowing population recovery. Recommendations to standardize and invigorate monitoring and conservation programs were also made.

In Nepal, gharial are restricted to remnant populations in the Karnali, Babai and Narayani rivers (tributaries of the Ganges). Total population is estimated at about 60 wild and 70 released gharials (Maskey and Percival 1994). A captive rearing program has released 432 gharial since 1978 and breeding of released gharials was recently reported (Maskey 1994). Most releases have been into the Narayani and its tributaries in central Nepal, with additional releases in the Koshi, Babai, Karnali and Rapti rivers.

Reports of gharial remaining in the Sind region of Pakistan are persistent (Ahmad 1990, Chaudhry 1993), but there appears to be a very small number, possibly only one or two individuals. The species is virtually extinct in Pakistan. The Pakistan government is currently planning a restocking effort with assistance from Indian institutions. A recent review of crocodiles in Bangladesh (Cox and Rahman 1994) suggest that although small numbers of the species continued to be reported into the 1980s it may no longer found in the wild. Known nesting areas that produced up to 12 nests as late as 1985 have seen none since 1990. The species is heavily impacted by fishing activities and habitat degradation. A part of the distribution on the Padma river is periodically moved into Indian jurisdiction as the river channel changes during floods. The gharial is in imminent danger of extirpation in Bangladesh. Historic reports of gharial in Myanmar have not been verified for many years, but recent reports confirm that populations persist in the upper Brahamputra and in Bhutan.

The gharial is still very threatened. Gharial are extremely rare in both India and Nepal, virtually extirpated in Pakistan, Bhutan and Bangladesh, and probably extinct in Myanmar.

Priority projects

High priority

Survey of status and distribution in Pakistan: The government of Pakistan is interested in implementing a restocking program similar to the ones in Nepal and India. However, apart from one recent sighting nothing is known about the status of the gharial. Surveys of the Indus River and Nara Canal are needed. Based on the results of this survey, action should be taken to set aside land for crocodile sanctuaries as a first step towards restocking.

A National Management Plan for gharial in India and implementation of the recommendations of the Gharial PHVA: Additional projects that should be developed under this program would include coordinated surveys and monitoring, genetic and migration studies, improved restocking activities, public education and periodic re-analysis of the status of the species.

Development of international coordination for gharial management and conservation between India and Nepal: Gharial populations occupy rivers that run between India and Nepal. Independent conservation programs are in effect in each country. Coordinated management of these shared populations would enhance conservation effectiveness. Joint surveys, training comparison of population trends and coordinated regulations and protection should be developed.

Establishment of a captive rearing center in Pakistan:A captive rearing center similar to those in India and Nepal is needed to supply animals for restocking in protected areas.

Moderate priority

Status survey in the Irrawaddy and Kaladan River systems in Myanmar: Although the gharial is considered to be extinct in Myanmar, small populations may still exist in isolated areas. Surveys need to be conducted to assess the current status of gharial in Myanmar.

Expansion of restocking program in Nepal: The vast majority of the releases of gharial in Nepal have been into the Narayani River system. Additional sites in eastern and western Nepal need to be identified and included in the restocking program.

Gharial, Gavialis gangeticus, captive breeding stock at Nandakan
Crocodile Center, Orissa, India. Restocking is maintaining this species
in some protected localities such as the Chambal River.
Photo by R. J. Rao.