Species Fact Profile: Indian Gharial (Gavialis gangeticus)

                                                           Indian Gharial (Gavial)

                                           Gavialis gangeticus (Gmelin, 1789)

Range:  India, Nepal, Bangladesh (historically also Pakistan, Bhutan, and Myanmar) 

Habitat: Clear Freshwater Rivers.  Prefer ones with deep water and sandbars

Diet:  Fish.  Juveniles also eat insects, crustaceans, and amphibians

Social Grouping:  Not especially sociable, but habitat preferences tend to cause individuals to congregate in groups of decent size, such as basking on favored sandbars

Reproduction:  Mate in the dry season.  Males court females by buzzing with their gharas and clapping their jaws underwater, then following females and rubbing them with their snouts.  If the female is receptive, she will point her head skyward and ten the male will mount her.  Copulation occurs underwater and may last for 30 minutes.  Females dig nest burrows in sandy riverbanks within a few meters of the water’s edge and guard the nest for the 60-80 day incubation period (warmer areas incubate faster).  Nest holes are about 50 centimeters deep, usually dug at night.   Most females lay 28-60 eggs, very large ones can lay almost 100.  Eggs are 5.5 centimeters wide, 8.6 centimeters long, and weigh 100-156 grams.  Females guard their nest sites from other animals, but are tolerant of other females nesting on the same beach.  Sex of the hatchlings is determined by incubation temperature.

Lifespan: 50-60 Years

      Conservation Status:  IUCN Critically Endangered  CITES Appendix I

• Males can grow 5-6 meters long, records approaching 6.5 meters, while females are usually less than 4 meters.  Weigh 159-181 kilograms – one of the largest crocodilians
• Adults are a dark brown or greenish brown on the dorsal surface, fading to white or pale yellow on the underside.  Juveniles have dark bands on the body and tail that fade with age.  Scales are much smooth than those in other crocodilians
• Most recognizable trait is the snout, which is long and slender, specialized for catching fish.  It grows progressively longer and thinner as the animal ages.  There are approximately 105-110 teeth in the mouth. 
• Males are distinguished from females by having a bulbous growth at the end of their top jaw, called the “ghara,” for which they are named (from a traditional Indian pot).   It helps the male vocalize to females while also serving as a visual cue of his size and fitness, can also help blow bubbles.  The cartilaginous lid on the nostrils produces a loud buzzing noise when flapped.  They are the only living crocodilian that displays such sexual dimorphism
• Gharial are poorly adapted to walking on land and have weak leg muscles; can only drag themselves along the ground.  Their feet are more webbed than those of other crocodilians   
• Young are 18 centimeters long upon hatching.  They are dug from the nest by the female, sometimes with help from the male.  They are not carried in the jaws of the parents like many other crocodilians are (probably because of the snout shape), but are looked after by the female (and at least tolerated by the male), usually until they are dispersed by the monsoon.  Females are sexually mature at 3 meters long (about 8 years), males at 4 meters long (about 15 years), at which time they begin to develop their ghara
• The primary feeding strategy is to float in the water until prey happens to pass them by.  In other cases they may actually hunt for fish, using the sense organs on their scales to detect movement in the water.  Their very thin jaws create little resistance in the water, allowing them to quickly snap shut.  Adults occasionally prey on crustaceans and turtles.  Sare their range with the mugger crocodile (Crocodylys palustris), but avoid competition through use of different prey bases and nesting sites
• Adults have no predators.  Eggs and hatchlings may be vulnerable to jackals, wild boars, mongooses, monitor lizards, and large fish, among other predators
• Species is probably harmless to humans, despite some anecdotal fears of people being attacked.  They are not aggressive, and despite their large size, their narrow jaws and thin teeth make them poorly suited to preying on large mammals.  Some human remains and jewelry have been found in gharial stomachs, but it is believed these are from bodies placed in the river as part of Hindu funeral ceremonies, parts of which may be swallowed by gharials as gasttroliths
• The first crocodilian to be classified as critically endangered.  300-900 mature individuals in the wild.  Numbers increasing, reintroductions underway.  Populations decline drastically between 1997 and 2006 (an estimated loss of 50-60% across their range).  The major threat is loss of habitat, as well as disturbance caused by deforestation, mining, and agricultural on the river banks.  Dam construction floods other suitable nesting sites and makes them unusable.  Overfishing can deplete their prey base.  Individuals are sometimes entangled and drowned by fishing nets
• They are also subject to some poaching pressure – mostly for eggs, but sometimes adult males are poached for their ghara, which are believed to have aphrodisiacal properties, as well as their fat and penises
• More recent threat is gout, believed to be caused by introduced tilapia in the Yamuna River, which may have a toxic impact on gharials
• Depictions of gharials in art date back at least 4000 years in the Indus Valley; Hindus regard it as the vehicle of the river god Ganga