Gharial

The **gharial** (*Gavialis gangeticus*), sometimes called the **Indian gharial**, **common gharial** or **gavial**, is one of two surviving members of the family Gavialidae. They are a group of crocodile-like reptiles with long, narrow jaws. 

The gharial is the second-longest of all living crocodilians: a large male can be nearly six meters in length. Only saltwater crocodiles and the Nile crocodile can grow larger.

## Ancestry 
The fossil history of the Gavialoidea is quite well known. The earliest examples split from the other crocodilians in the late Cretaceous. The feature of the group that is easiest to recognise is the very long, narrow snout.  This is an adaptation to a diet of small fish. Gharials have sacrificed the great mechanical strength of the robust skull and jaw that most crocodiles and alligators have. For this reason,  and they cannot prey on large creatures. But they also have reduced weight and water resistance of their lighter skull and very narrow jaw. This gives gharials the ability to catch rapidly moving fish. They catch them with a side-to-side snapping motion.

The earliest Gavialoidea may or may not have been related to the modern types: some died out at the same time as the dinosaurs (at the end of the Cretaceous), others survived until the early Eocene (about 35 million years ago).  The modern forms appeared at much the same time. They evolved in the estuaries and coastal waters of Africa. They crossed the Atlantic to reach South America as well. At their peak, the Gavialoidea were numerous and diverse, they occupied much of Asia and America up until the Pliocene. One species, *Rhamphosuchus crassidens* of India, is believed to have grown to an enormous 15 metres or more.

## Distribution 
Northern Indian subcontinent: Bhutan (almost extinct), Bangladesh (close to extinction), India (present in small numbers and increasing), Myanmar (possibly extinct), Nepal, Pakistan (close to extinction). Usually found in the river systems of Indus (Pakistan) and the Brahmaputra (Bangladesh, Bhutan & North eastern India), the Ganges (Bangladesh, India & Nepal), and the Mahanadi River (in the  rainforest biome) (India). Small numbers are in Kaladan and the Ayeyarwady in Myanmar. It is sympatric, in respective areas, with the mugger crocodile (*Crocodylus palustris*) and the saltwater crocodile (*Crocodylus porosus*).

## Habitat 
Gharials live in rivers. They are best adapted to the calmer areas in deep fast moving rivers. Their physical attributes do not make the animals very suited to walk on land. In fact the only reasons the gharial leaves the water is to either bask in the sun or to nest on the sandbanks of the rivers.

## Appearance 
The Gharial has a long, narrow snout. This is the feature that is most different from most other Crocodilia. The only other species who has such a snout is the False gharial (*Tomistoma schlegelii*), which is closely related. The shape of this snout changes when the animal grows older. The snout becomes progressively thinner the older the gharial gets. There is a  bulbous growth on the tip of the male's snout. This is called a 'ghara' (after the Indian word meaning 'pot'). It is only present in mature animals. It is used for different activities, such as making a resonant hum during vocalization. It is also used for attracting females. The mating ritual includes a section where the male uses this ghara to make bubbles.

The long jaws are lined with many interlocking, razor-sharp teeth. This is an adaptation to the diet (predominantly fish in adults). This species is one of the largest of all crocodilian species, approaching the saltwater crocodile (*Crocodylus porosus*) and the Nile crocodile in maximum size - males reach at least 5 metres in length, and often approach 6 metres. Reports of 7 metre animals exist, but are unconfirmed. The leg musculature of the gharial is not suited to enable the animal to raise the body off the ground (on land) in order to achieve the high-walk gait - being able only to push its body forward across the ground ('belly-sliding'), although it can do this with some speed when required. However, when in water, the gharial is the most nimble and quick of all the crocodiles in the world. The tail seems overdeveloped and is flattened on the side, more so than other crocodiles. This enables it to achieve the excellent swimming abilities.

The gharial has 27 to 29 upper and 25 or 26 lower teeth on each side. These teeth are not received into interdental pits; the first, second, and third mandibular teeth fit into notches in the upper jaw. The front teeth are the largest. The gharial's snout is narrow and long, with a dilation at the end and its nasal bones are comparatively short and are widely separated from the pre-maxillaries. The nasal opening of a gharial is smaller than the supra-temporal fossae. The gharial's lower anterior margin of orbit (jugal) is raised and its mandibular symphysis is extremely long, extending to the 23rd or 24th tooth. A dorsal shield is formed from four longitudinal series of juxtaposed, keeled and bony scutes.

The length of the snout is 3.5 (in adults) to 5.5 times (in young) the breadth of the snout's base. Nuchal and dorsal scutes form a single continuous shield composed of 21 or 22 transverse series. Gharials have an outer row of soft, smooth or feebly-keeled scutes in addition to the bony dorsal scutes. They also have two small post-occipital scutes.

The outer toes of a gharial are two-thirds webbed, while the middle toe is one-third webbed. Gharials have a strong crest on the outer edge of the forearm, leg and foot. Typically, adult gharials are of a dark olive hue while young ones are pale olive, with dark brown spots or cross-bands.

## Taxonomy 
The gharial and its extinct relatives are grouped together by taxonomists in several different ways:

* If the three surviving groups of crocodilians are regarded as separate families, then the gharial becomes one of two members of the Gavialidae, which is related to the families Crocodylidae (crocodiles) and Alligatoridae (alligators and caymans).
* Alternatively, the three groups are all classed together as the family Crocodylidae,  but belong to the subfamilies Gavialinae,  Crocodylinae, and Alligatorinae.
* Finally, palaentologists tend to speak of the broad lineage of gharial-like creatures over time using the term Gavialoidea.

Janke *et al.* (2005), using molecular genetic evidence, found the gharial and the false gharial (*Tomistoma*) to be close relatives, and placed them together in the same family.

Common names include: Indian gharial, Indian gavial, Fish-eating crocodile, Gavial del Ganges, Gavial du Gange, Long-nosed crocodile, Bahsoolia, Nakar, Chimpta, Lamthora, Mecho Kumhir, Naka, Nakar, Shormon, Thantia, Thondre, Garial.

### Classification 
* **Order Crocodilia**
** **Superfamily Gavialoidea**
*** Family Gavialidae

## Related pages
* Indus crocodile
* False Gharial

## References 
*  Listed as Endangered (EN C2a, E v2.3)
* Janke A, Gullberg A, Hughes S, Aggarwal RK, Arnason U. (2005). "Mitogenomic analyses place the gharial (Gavialis gangeticus) on the crocodile tree and provide pre-K/T divergence times for most crocodilians." J Mol Evol. 61(5):620-6.

## Other websites 
* http://reptilis.net/crocodylia/gavies/gavialidae.html a less formal article, great photos
* http://www.vic.com/nepal/images/gharial.html  photo of a large specimen in the wild
* http://www.flmnh.ufl.edu/cnhc/!ggan1.htm teeth and feeding
* http://www.whozoo.org/students/lydia/gharials.htm excellent photos from Fort Worth Zoo
* http://www.oneworldmagazine.org/tales/crocs/gharial.html  a charming folk tale
* http://www.scz.org/animals/g/gharial.html  species summary from Sedgwick County Zoo
* http://www.itis.usda.gov  ITIS Taxonomic Serial No.: 202217