BREEDING:
Females reach sexual maturity around 3 m in length (usually over 10 years old). Males guard a harem of several females. The mating period occurs for two months during November, December and into January. Nesting occurs in March, April and May (the dry season) where hole nests are dug into seasonally-available riverine sand banks. Between 30 and 50 eggs (average of 37) are deposited into the hole before it is covered over carefully. The size of the eggs in gharials is the largest for any crocodilian species, weighing on average 160 grams. After 83 to 94 days, the juveniles emerge, although the female has not been observed assisting the hatchlings to the water as in many other crocodilian species. This is perhaps because of the unsuitability of their jaws for carrying hatchlings, and also because of their needle-sharp teeth. However, protection of the young does occur around the nesting area for some time after hatching.
CONSERVATION:
The gharial is in serious trouble once more. In the first half of the 20th Century the gharial was common throughout its range, with an inferred population in the 1940s of between 5,000 and 10,000. By 1970, however, it was apparent that the gharial was in serious decline and this prompted scientific surveys to determine the extent of the problem. These were initially carried out by S. Biswas of the Zoological Society of India, and then extended into an India-wide survey conducted by Rom Whitaker. Full protection was granted in the 1970s in the hope of reducing poaching losses, although these measures were slow to be implemented at first. A total of 9 protected areas were established in India linked to both captive breeding and 'ranching' operations where eggs collected from the wild were raised in captivity (to reduce mortality due to natural predators) and then released back into the wild (the first being released in 1981). Over 3000 animals were released through these programs, and the wild population in India recovered to an estimated 1500 adults - with perhaps between one and two hundred animals in the remainder of its range (Pakistan, Bangladesh, Nepal).
Yet despite this recovery, surveys within the last decade have revealed that populations are once again in decline, and this time it is looking grim. Available habitat is being eroded, fishing and pollution are serious threats to both juveniles and adults, and populations have disappeared from many former haunts. By 2007 the gharial was once again elevated to the status of CRITICALLY ENDANGERED on the IUCN Red List. This is the first crocodilian species to have been re-listed in this manner.
The major threat at present is habitat loss due to human encroachment, sand mining and disruption of populations through fishing and hunting activities. Pollution is also suspected to be a serious factor, possibly to blame for a mass die-off of adults in early 2008. A historical problem has also been a lack of suitable release sites for any release programs. Gharial eggs are occasionally collected by local people for medicinal purposes, and males have been targeted for the aphrodisiac properties associated with the snout. They may also be snared in fishing (gill) nets and killed by fishermen. The decline in 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 crocodiles' diet.
The Gharial Conservation Alliance (GCA) was established in 2007 and comprises key gharial scientists, experts and stakeholders primarily in gharial range states. Starting with fund- and awareness-raising campaigns, it is coordinating research and conservation activities on remaining populations and habitats. Key priorities include protecting all remaining suitable habitats from illegal activities that threaten gharials, monitoring and research on current populations, addressing human impacts on gharials and riverine habitat, and establishing conservation programs with local communities.
MORE INFORMATION:
For more information on distribution and conservation issues for this species,see the CSG Action Plan resource.
SIGNIFICANT REFERENCES:
Bustard, HR & Singh, LAK (1978). Studies on the Indian gharial, Gavialis gangeticus (Gmelin) (Reptilia, Crocodilia). Change in terrestrial locomotory pattern with age. J. Bombay Nat. Hist. Soc. 74: 534-536
Maskey, BGH & Bellairs, AD'A (1977). The narial excresence and pterygoid bulla of the gharial, Gavialis gangeticus (Crocodilia). J. Zool., Lond. 182: 541-558
Rao, RJ & Singh, LAK (1994). Status and conservation of the gharial in India. In: Crocodiles. Proceedings of the 12th Working Meeting of the Crocodile Specialist Group. IUCN, Gland, Switzerland. Vol.1. pp. 84-97
Singh, LAK & Bustard, HR (1977). Studies on the Indian gharial, Gavialis gangeticus (Gmelin): V. Preliminary observations on maternal behavior. Indian Forester 103: 671-678
Whitaker, R & Basu, D (1983). The gharial (Gavialis gangeticus): a review. J. Bombay Nat. Hist. Soc. 79: 531-548