Thursday, June 16, 2011

Gharial

Gharial

                                                                   (Gavialis gangeticus)




  • The gharial (Gavialis gangeticus), ( Hindi: घऱियाल, Marathi: सुसर Susar), also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts. The gharial is listed as a critically endangered species by IUCN. The gharial is one of the three crocodilians found in India, the others being the Mugger crocodile and the Saltwater crocodile. It is one of the longest of all living crocodilians.




  • Description: The Gharial, Gavialis gangeticus is uniformly dark olive-gray with a pale yellow belly. Juveniles have dark spots and cross bands against a light background. Gharials have an extremely elongated snout. The teeth are needle-like and the eyes green frosted with back. A large male can reach 23 feet in length, and a female 15 feet.Gharials, being the most aquatic of all crocodilians, are awkward out of water mainly due to their short stumpy legs. The adult male develops a pot-like structure on the end of the snout, giving the gharial its name (from    "ghara" -- Hindi for earthen pot). This nose knob is used to produce a bussing noise that repels rival males and serves as an audible warning system.  The leg musculature of the gharial does not enable it to raise its body off the ground to achieve the high-walk gait on land, but can only 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 crocodilians in the world. The jaws are lined with many interlocking, razor-sharp teeth — 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.

  • Distribution and Habitat: Gharials thrive in deep rivers. They are powerful swimmers but graceless on land, and will leave the water only to bask or to nest on sandy beaches. They were once distributed across approximately 20,000 square kilometres (7,700 sq mi) of riverine habitat of the Indus, Ganges, Brahmaputra, and Irrawady river systems. Today their distribution is limited to only 2% of their former range. In India, small populations are present and increasing in the rivers of the National Chambal Sanctuary, Katarniaghat Wildlife Sanctuary, Son River Sanctuary and the rainforest biome of Mahanadi in Satkosia Gorge Sanctuary, Orissa, where they apparently do not breedIn Nepal, small populations are present and slowly recovering in tributaries of the Ganges, such as the Narayani-Rapti river system in Chitwan National park and the Karnali-Babai river system in Bardia National Park.

  • Diet: Young gharials eat insects, larvae, and small frogs. Mature adults feed almost solely on fish, although some individuals have been known to scavenge dead animals. Their snout morphology is ideally suited for preying on fish. Their long, narrow snouts offer very little resistance to water in swiping motions to snap up fish in the water. Their numerous needle-like teeth are ideal for holding on to struggling, slippery fish. Gharials will often use their body to corral fish against the bank where they can be more easily snapped up.

  • Threats: Gharials have been pushed to the brink of extinction. In 1974, the government of India and the United nations Food and Agriculture Organization conducted a survey of its population in India. It was estimated that no more than 50 to 60 surviving adults.Although the gharial is still listed as endangered, effective conservation measures have now made the gharial's future more promising. Massive sanctuaries have been created and active management involves the collection of eggs for hatchery incubation.







Tuesday, June 14, 2011

Indian Skimmer




Indian Skimmer
(Rynchops albicollis)

  • Description: A crow sized, tern-like bird, blackish brown above and glistening white below; a broad white forehead, sides of face and a collar, contrasting with the black head and nape; a dark stripe down the middle of the white rump and forked tail. A typical knife-like compressed bill, with longer lower mandible, orange yellow in colour; legs bright red. Immature lighter brown above, scalloped with fulvous white; forehead with brown streaks; tail-feathers tipped brown.

  • Distribution: It is found on large rivers and lakes, swamps and coastal wetlands such as estuaries. It is most common on freshwater, particularly during the breeding season. Breeding colonies are on islands or sandy spits, usually in rivers. Its range has become increasingly fragmented in recent decades. It is still found in parts of Pakistan in the Indus river system of Kashmir and northern and central India along the Ganges, Bangladesh and Burma. It is a scarce non-breeding visitor to Nepal and has occurred as a vagrant in Oman and central Thailand with old records from Iran and China. They are more widespread in winter and are found in coastal estuaries of western and eastern India. Breeding colonies are known from the Chambal river area, an area that is of importance for the Gharial. Sand banks are important for the nesting of Gharials.

  • Behavior and Diet: The birds forage for food by flying low over the water with the bill open and the lower mandible skimming through the water. When a fish is encountered, it moves up the lower mandible and the bird raises the upper mandible and snaps it with a movement of the head. They forage in small flocks and often associate with terns. They feed mainly on fish but also take small crustaceans and insect larvae. They often feed at dusk and can be very nocturnal. The breeding season is mainly March and May. They breed in colonies of up to 40 pairs, often with terns and other birds. The nest is a simple scrape on the ground mainly on open sand banks that provide unobstructed views of any oncoming predators. The eggs are buff or white with brown blotches and streaks. There are three to five eggs in a clutch. The birds tend to incubate the eggs more during the cooler hours of the day and are often away from the nest during the hotter parts of the day. Incubating adults are said to indulge in belly-soaking behaviour to cool the eggs. A bird at nest was once observed to pick up (and drop into water) an intruding chick of a River Tern using its leg.

  • Threats: Increased disturbances in the breeding ground along the sandy banks of major rivers due to fishing activities, probable shortage of food (of appropriate size) and increased pollution of river waters in recent times are probable causes of depletion of the species.



Indian Skimmer : Fishing