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Gharial

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Gharial
Indian Gharial Crocodile Digon3.JPG
Scientific Classification
Binomial Name

Gavialis gangeticus

Gavialis gangeticus.jpg
Gharial sun bathing

Gharials (Gavialis gangeticus) are a critically endangered crocodilian species native to the Northern Indian Subcontinent. They are the only living species of the genus Gavialis. They are large and slender, growing to be between four to six meters in length. Gharials are best known for their long narrow snout. The males have a gahar (a growth on the end of their nose) that is used to manufacture sounds during courtship. The gharial has very sharp teeth that they use to catch fish. They are either grey or olive in color with the juveniles being paler [3].


Body Design

The gharial pokes it narrow snout out of the water

Gharials are among the largest crocodilians. The only other crocodilian that can grow larger is the saltwater crocodile. Gharials can grow to be between thirteen and twenty-three feet long. A full grown adult can weigh anywhere from 1500 to 2000 pounds. Gharials are best recognized for their long, slender snout. Another distinguishing characteristic involves its tail. The tail is flattened and rimmed on both edges by a ridge of scales[4].

The gharial is designed for life in the water. Its webbed feet along with its flattened tail gives the gharial great quickness and dexterity while moving underwater. Its narrow nose also creates little resistance in the water, which allows its jaw full of teeth to snatch up prey. On land however the gharial is far less mobile. Their legs are not strong enough to lift their body off the ground. So in order to move on land, the gharial pushes itself along by sliding on its abdomen[4].

Life Cycle

The gharial’s life cycle begins with the mating of a female and a male. Females become sexually mature once they reach about three meters in length. Often this occurs after the female reaches ten years in age. The males will protect a harem (females that he mates with) of a few females. The mating season lasts for two months, occurring in November, December, and lasting into January. The females begin nesting in the dry season during the months of March, April, and May. These nests (holes in the sand) are constructed in the riverine sand banks which become available during the dry months. Each nest can contain between thirty to fifty eggs, with the average being thirty-seven. The gharial’s eggs are the largest of any crocodilian species. On average they weigh 160 grams. After an incubation period of eighty-three to ninety-four days, the young gharials hatch and make their way out of the nest. Unlike other crocodilian species, the mother has not been witnessed helping the young into the water. This may be the result of their needle-sharp teeth and that they have very narrow jaws. Nevertheless, the young do receive protection around the nesting area for a period of time after hatching[5]. In the wild the gharials can live to be between forty and sixty years old[6].

Ecology

Gharial range map

Gharials (Gavialis gangeticus) are the only living member of the genus Gavialis, a genus that once included five species[4]. Known populations of gharials can only be found on the Northern Indian Subcontinent. They exist only in India and Nepal. Historically, there were populations in Bangladesh, Pakistan, Bhutan and Myanmar. Remaining populations capable of breeding in India are located in the: Chambal River, Gitwa River, Son River, and Mahanadi River. Several non-breeding adults can be found in the: Ken, Ramgenga, Yamuna, and Brahmaputra rivers. In Nepal breeding gharials are found in the Narayani/Rapti River, while non-breeding gharials are in the Karnali, Babai, and Koshi rivers[5].

Gharials are carnivores[4]. Young gharials are able to consume a wide variety of prey from insects to small vertebrae such as frogs. As for the adults, they almost solely eat fish. Their jaws and teeth are designed perfectly for catching and eating fish. Their narrow snouts allow them to slice through the water while feeling little resistance[5].

Species Survival

The gharial is listed as critically endangered on the IUCN Red List of Threatened Species. Gharials are one of the most critically threatened crocodilians, and almost became extinct in the 1970s. Recently, the species had made some recovery. With the help conservation efforts and management programs they have continued to survive. There are nine protective areas in India and captive breeding and ranching operations are being used. But even with all of this special attention and effort, the total population of the species is estimated to be less than 1,000 animals[7].


The species largest threat is loss of habitat due to human activity and the changing fish populations. Other threats include a lack of usable release sites has become a problem for managing the gharial. As well as the fact that gharial eggs are collected for medicinal purposes and the males are often hunted for their snout. They also can get caught in fishing nets and as a result are killed by fishermen. Moving forward the gharial must deal with all of these threats if the species is going to survive. As for the future, management and conservation programs will continue to gather data as well as make revisions to allow the continued survival of the gharial[7].

Video

In India, an endangered crocodilian species clings to survival in a river sanctuary threatened by human activity.

References

  1. Eukaryota EOL. Web. 2-10-2013(Date-of-access).
  2. King, F. W., and R. L. Burke, eds. Gavialis-gangeticus ITIS-Report. Web. 2-10-2013(Date-of-access).
  3. Gharial ‘’ The –Animal-Files.com. Web. 2-27-2013(Date-of-access).
  4. 4.0 4.1 4.2 4.3 Klappenbach, Laura. Gharial About.com. Web. 2-11-2013(Date-of-access).
  5. 5.0 5.1 5.2 Gavialis-gangeticus CSL. Web. 2-24-2013(Date-of-access).
  6. Gavialis gangeticus National Geographic. Web. 2-24-2013(Date-of-access).
  7. 7.0 7.1 Gharial Smithsonian-National-Zoological-Park. Web. 2-24-2013(Date-of-access).