GHARIAL: Gavialidae

PHYSICAL CHARACTERISTICS

The lone species of gharial (GAR-ee-ul), also sometimes known as a gavial, looks much like a crocodile or alligator except that a gharial has an extremely long and thin snout. The narrow jaws in both males and females are lined with more than 100 pinpoint-sharp teeth. The back of a gharial is covered with tough scales, but these scales are not lumpy as they are in many alligator and crocodile species. Gharial scales are very smooth. Adults are dark brown or greenish brown on top and yellowish white to white below. Young gharials have dark bands on the body and tail. Adults also have bands, but they fade and become less noticeable as the animal gets older. The name gharial comes from the round knob that forms on the tip of the adult male's snout above the nostrils. This knob is called a ghara, because it looks somewhat like an Indian pot of the same name.

Gharials are large reptiles. Males usually grow to 13 to 15 feet (4 to 4.5 meters) long and 350 to 400 pounds (181 kilograms), although some can reach nearly 20 feet (6.1 meters). Females are a bit smaller, usually reaching 11.5 to 13 feet (3.5 to 4 meters) in length. They have long and powerful tails. They are so strong that the gharial need only sway its tail side to side to glide through the water. While swimming, it usually holds its legs back and alongside the body and does not move them.

People sometimes confuse the gharial with the false gharial. Both are large animals with a similar shape. The false gharial, also known as the Malayan gharial, has a long and thin snout, but it is not quite as long and thin as that of the true gharial. The false gharial also has a heavier-set body. The false gharial is usually placed in the crocodile family, but a 2003 comparison of its DNA now suggests that it should be considered part of the gharial family. Every cell in the body contains DNA, which provides the instructions for making a specific species of animal. Scientists compare the DNA in different species, such as the false gharial and the gharial, to help them decide which animals are most closely related.

GEOGRAPHIC RANGE

Gharial populations are scattered here and there in India, Nepal, and Pakistan, and individuals are sometimes spotted in Bangladesh and Bhutan.

HABITAT

Gharials live in clear, freshwater rivers with swift currents but prefer river bends and other areas where the water is flowing more slowly and is quite deep. They also seek out sandbars in the middle of the river and use them for sunbathing, or basking, to warm their bodies. Strangely, this freshwater animal has salt glands, which are found in animals that live in saltwater. The glands are small organs that get rid of extra salt. Scientists suspect that the gharial once—perhaps millions of years ago—could survive in saltwater and may have traveled across the oceans.

MORE THAN A LUMPY NOSE

Scientists have long wondered about the round growth that appears on the nose of male gharials when they become adults. Many suspect that the growth, called a ghara, may do more than allow the animal to make its unusual buzzing sounds. Some researchers believe that the ghara helps the male to produce bubbles. Both the buzzing and the bubbles may help the males attract females during the mating season. Other scientists guess that the gharials look for the ghara to tell quickly which individuals are males and which are females.

DIET

As youngsters, gharials eat tadpoles, shrimp, insects, and fish they find in the water. As they get older, they become more selective and will eat almost nothing but fish. They usually hunt by ambush, which means that they remain completely still and wait for a fish to swim close. At that point, their unusual teeth become useful. At the front of the lower jaw, a gharial's teeth face outward at such an angle that the tip of the mouth when it is closed looks like a pin cushion. As the fish nears, the gharial snaps its jaws sideways at the prey and stabs it with these very sharp teeth. With a upward jerk of its head, the reptile flings the fish off of its teeth and into the back of its mouth.

BEHAVIOR AND REPRODUCTION

Like some of the other alligators and crocodiles, gharials usually get along quite well and live together in groups. They stay in the water most of the time, coming out occasionally to bask on shore. While they are excellent swimmers, they are slow on land and must drag their bellies and tails on the ground when they walk. They rarely wander too far from the water's edge and, at the slightest threat, will dive back into the safety of the river. On especially warm days, they may open their mouths wide to cool off. This serves the same purpose as panting does for a dog.

When mating season arrives in December and January, the adult males begin fighting one another to set up and defend territories in shallow water. Their fights look something like wrestling matches. Two males lie side by side, lift their heads out of the water, and begin pushing each other with their snouts. The winner is the one that can topple over the other. Sometimes, the wrestling matches become more violent, and the two males hit each other with their snouts or bite each other. A male with a good territory may be able to attract several large females to mate with him. Scientists also believe that the size of the male's ghara may also be important during the mating season. The males can use the ghara to produce a loud buzz, which may be attractive to females. Males also will buzz to warn other males to stay away.

After mating, a female will lay her eggs sometime from March to May. She crawls up a steep bank at the riverside and begins looking for a spot for her nest. She digs her nest in dry ground at least 5 feet (1.5 meters) above water level. A female gharial is very fussy about her nest and may change her mind several times, even after starting to dig, before settling on the perfect place to lay her eggs. The female becomes territorial and guards her specific nest sites from other females, although she will share the beach with many other females and their nests. After digging a hole in the sand, she lays her eggs inside and carefully covers them. The smallest females lay as few as a dozen eggs, and many first-time mothers lay eggs that never hatch at all. The largest females, on the other hand, may lay almost 100 eggs. A typical gharial egg is 2.2 inches (5.5 centimeters) wide, 3.4 inches (8.6 centimeters) long, and weighs 5.5 ounces (156 grams). Females remain near their nests and will defend them from predators, if necessary. The eggs hatch 53 to 92 days later, with nests in warmest climates hatching out earliest and babies in the coolest areas breaking out of their eggs last. The temperature of the nest also controls the number of males and females. Especially warm nests produce more males, and cooler ones produce more females.

The mother gharial helps her young out of the nest, and then she and possibly the father watch over them. Despite this care, many of a female's young do not survive. Numerous animals, including pigs, hyenas, monitor lizards, and some humans, are fond of gharial eggs, while some birds and turtles often gobble up babies. In addition, the babies are born during the monsoon season and often drown in the floods that are common at this time of year. Of those that do survive, the females are ready to mate when they reach about 10 feet (3 meters) long and are at least 8 years old. The males can mate once they are 15 years old and about 11.5 feet (3.5 meters) long.

GHARIALS AND PEOPLE

Local people sometimes gather gharial eggs for food or hunt the males for the ghara, which they use to make potions. Some people fear gharials, but they do not attack or eat humans. This reptile does, however, hold a place in Hindu legends of a river goddess, named Ma Ganga, who rides on a gharial's back.

CONSERVATION STATUS

The World Conservation Union (IUCN) and the U.S. Fish and Wildlife Service consider this species to be Endangered, which means that it faces a very high risk of extinction in the wild and throughout all or a significant portion of its range. In some areas, the gharial has already disappeared or is nearly gone. The greatest threat to this species is habitat loss, often caused when people clear land for farming or for firewood. Conservationists have raised and attempted to release young gharials into the wild. Some of these efforts have been successful, and others have not, but the work to save this unusual species is continuing.

FOR MORE INFORMATION

Books:

Daniel, J. C. The Book of Indian Reptiles and Amphibians. New Delhi, India: Oxford University Press, 2002.

Ross, C. A., ed. Crocodiles and Alligators. New York: Facts on File Inc., 1989.

Rue, Leonard Lee. Alligators and Crocodiles. Wigston, Leicester: Magna Books, 1994.

Web sites:

"Alligators and Crocodiles." San Diego Zoo. http://www.sandiegozoo.org/animalbytes/t-crocodile.html (accessed on September 21, 2004).

"At the Zoo: Gharials Star in the Reptile Discovery Center and on Gharial Cam." Smithsonian National Zoological Park. http://nationalzoo.si.edu/Publications/ZooGoer/2002/6/gharials.cfm (accessed on December 19, 2004).

"Gavialis gangeticus (GMELIN, 1789)." Florida Museum of Natural History. http://www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp_ggan.htm (accessed on December 19, 2004).

"Gharial." Smithsonian National Zoological Park. http://nationalzoo.si.edu/Animals/ReptilesAmphibians/Facts/FactSheets/Gharial.cfm (accessed on September 21, 2004).

"The Gharial and the Monkey." The Crocodile Files. http://www.oneworldmagazine.org/tales/crocs/gharial.html (accessed on December 19, 2004).