SALTWATER CROCODILE -
Crocodylus Porosus (SCHNEIDER, 1801)
English: Saltwater Crocodile, Estuarine Crocodile. Oriya: Baula kumbhira, Kuji Khumbhiora. Hindi, Gujarat, Marathi: Muggar. Bengali: Kuhmir. Kannada: Mossalay. Tamil: Muthalai. Telugu: Moseli. Malayalam: Muthala, Cheengkani.
Distribution, Habitat & Size: Probably the largest of the present day reptiles. The largest skull available measures 1
metre in length and it is believed to have belonged to a specimen of about 7 metres in
length. Specimens over 5 m in length have been obtained in the Sunderbans and in Orissa river estuaries but are now exceedingly rare. A 4.5 m long captive specimen weighed 408 kg.
In India, the estuarine crocodile is restricted in its distribution to the tidal estuaries, marine swamps, coastal brackish water lakes and lower reaches of the larger rivers. The saltwater crocodile has a vast geographical range that extends from Cochin on the west coast of India to the Sunderbans in West Bengal and to the Andaman Islands. Single individuals can be found some distance from their usual range as they can travel long distances (over a thousand km) by sea. Barnacles have been found on the scales of a few stray individuals. This sea-faring ability probably helps to explain their wide distribution.
The species is seriously endangered, from hunting and now largely from loss of habitat, particularly breeding sites. Surveys in the Andamans have brought to light the precarious position of the animal in the Andaman and Nicobar Islands. It is now extinct in Kerala and Tamil Nadu. A sanctuary for the species has been established in the Bhitarkanika Island and Adjacent areas in the Brahmani Baitarni river estuary in Orissa.
As its name implies, this species has a high tolerance for salinity, being found in brackish water around coastal areas and in rivers. However, it is also present in freshwater rivers and swamps. Movement between different habitats occurs between the dry and wet season, and as a result of social status - juveniles are raised in freshwater areas, but eventually sub-adult crocodiles are usually forced out of these areas (used for breeding by dominant, territorial adults), into more marginal and saline areas. Subordinate animals unable to establish a territory in a tidal river system are either killed or forced out into the sea where they move around the coast in search of another river system.
Appearance: Largest living crocodilian species (in fact the largest living reptile in the world), adult males can reach sizes of up to 6 or 7 metres (20 to 23 feet). There is always a lot of interest over the largest ever recorded saltwater crocodile. In general, males over 5 m (17 feet) in length are extremely rare. Females are smaller, and do not normally exceed 3 m (10 feet), with 2.5 m being considered very large. This is a large-headed species with a heavy set of jaws. A pair of ridges run from the eye orbits along the centre of the snout. Scales are more oval in shape than other species, and scutes are relatively small. Juveniles are pale yellow in colour with black stripes and spots on the body and tail. A small percentage of animals in some regions tend to be much lighter in colour. The juvenile colouration persists for several years, growing progressively paler and less colourful with more indistinct bands which eventually disappear. Mature adults are generally dark, with lighter tan or grey areas. The ventral surface (belly) is creamy yellow to white in colour, except the tail that tends to be grey on the underside nearer the tip. Dark bands and stripes are present on the lower flanks, but do not extend onto the belly region.
Diet: Saltwater crocodiles take a wide variety of prey, although juveniles are restricted to smaller items such as insects, amphibians, crustaceans, small reptiles and fish. The larger the animal grows, the greater the variety of items that it includes in the diet, with only the smaller items taken less frequently. Prey items include crustaceans and vertebrates (e.g. turtles, snakes, shore and wading birds, buffalo and domestic livestock, wild boar, monkeys).
Breeding: Breeding territories are established in freshwater areas. Females reach sexual maturity at 10 to 12 years of age. Males mature later at around 16 years of age. 40 to 60 eggs are usually laid in mound nests made from plant matter and mud. These are constructed between the months of November and March during the wet season. This serves to raise the eggs above the ground to help prevent losses due to flooding. Alternately, if the nest is in danger of getting too dry, the female has been known to splash water onto it from a purpose-dug pool. Juveniles hatch after around 90 days, although this varies with nest temperature. The female digs the young out of the nest when they start their characteristic chirping sounds, assisting them to the water by carrying them in her mouth. Restocking programs in India (Bhitarkanika National Park in Orissa) have met with success.
CROCODILE - Crocodylus Palustris (LESSON, 1831)
English: Mugger, Marsh crocodile, Indian swamp crocodile. Hindi, Gujarat, Marathi: Muggar. Oriya: Kuji Khumbhiora. Bengali: Kuhmir, Kanada Mossalay. Tamil: Muthalai. Telugu: Moseli. Malayalam: Muthala, Cheengkani.
Distribution, Habitat & Size: Rarely over 4 m. Tow records slightly over 5.5 m in Sri Lanka. A 3.5 m specimen shot in Madhya Pradesh weighed approximately 200 kg. Another specimen 3.75 m in length, had a girth of 1.6 m, and required twelve men to lift it off the ground. They are found in India and possibly areas of Indo-China.
They prefer freshwater rivers, lakes and marshes and also slow-moving, shallow water bodies. They have also adapted to live in reservoirs, irrigation canals, and other man-made bodies of freshwater in India. Occasionally reported from saltwater lagoons. They are also known to live side by side with the gharials in some areas of India, but usually have separate habitat. They also dig burrows for shelter. They have been reported to migrate considerable distances over land (several km) in search of more suitable habitat. They Inhabits rivers, lakes and other larger bodies of water in the plains and up to 600 m in the hills, throughout the Indian subcontinent.
Appearance: Colour generally light tan in juveniles, with black cross-banding on body and tail. Adults are generally grey to brown, with little banding remaining. This is a medium to large species (4 to 5 m). The snout is the broadest of any member of the Crocodylus genus, giving the mugger a more alligatorine appearance. Enlarged scutes present around the throat area may serve a similar protective function when moving through shallow swampy areas.
In the field, the Mugger and the saltwater crocodile are difficult to distinguish from each other, but normally they do not occur together.
Diet: Juveniles take crustaceans, insects and small fish generally. Adults eat larger fish, amphibians, reptiles (mainly snakes and possibly turtles), birds and mammals (monkeys). Large adults have been known to take deer and buffalo on occasions.
Breeding: Females reach sexual maturity at around 1.7 to 2.0 m in length, while males mature at about 2.6 m. Nests are holes excavated during the dry season (from December to February). Location of the nest varies considerably (even within burrows on rare occasions, which is unusual as they are not normally associated with breeding activities), but they are most commonly found on sloping banks. The female usually lays 25 to 30 eggs. However, captive specimens have sometimes been observed laying two clutches per year, but this has yet to be observed under natural conditions. Eggs hatch after a relatively short period, usually 55 to 75 days, and the juveniles are around 30cm long at hatching. The female usually guards the nest, opens it and transports hatchlings to the water in her mouth, the male has been observed undertaking this task in captivity.
GHARIAL - GAVIALIS GANGETICUS
English: Indian gharial, Indian gavial, long-snouted crocodile. Hindi: Gharial. Bengali: Mecho kumhir. Oriya: Thantia kumhira, male: Ghadiala, female: Thantiana. Bihari: Nakar, Bashsoolia nakar.
Distribution, Habitat & Size: Maximum reported length 6.75 m. Believed to attain a length of up to 8 m.
Northern India subcontinent: In India, they are found within the river systems of the Brahmaputra, the Ganges, and the Mahanadi, with small populations in the Kaladan.
Riverine - more adapted to an aquatic lifestyle in the calmer areas of deep, fast-moving rivers. The gharial is poorly equipped for locomotion on land. It usually only leaves the water to bask and nest, both of which usually occur on sandbanks.
Confined to the Indus, Ganges, Brahmaputra and the Mahanadi river systems in the Indian subcontinent. Once very common, increasing human use of rivers has restricted the gharial to a few remaining wild stretches of it former habitat. Presently the main habitat is the Chambal, Girwa, Rapti and Narayani rivers of the Ganges system. The species is now rare and endangered.
Appearance: Easily distinguished from other crocodiles by the long and narrow snout which ends in a bulbous tip. Adult male have a large pot-like cartilaginous mass on the tip of the snout, hence the name Gharial (ghara = pot).
Adult dark olive or brownish olive. White or yellowish white below. Young grayish brown with five irregular transverse bands on the body and nine on the tail.
Characteristic elongate, narrow snout, similar only to the false gharial. Variation in snout shape occurs with age. The bulbous growth on the tip of the male's snout is called a 'Ghara' (after the Indian word meaning 'pot'), present in mature individuals. It has several functions attributed to it: a vocal resonator (which produces a loud buzzing noise during vocalisation), a visual stimulus to females, and the production of bubbles associated with sexual behaviour. The elongated jaws are lined with many interlocking, razor-sharp teeth - an adaptation to the diet (predominantly fish in adults). The gharial is one of the largest of all crocodilian species, approaching C. porosus in maximum size - males reach 6 to 7 metres in length. It is poorly equipped for locomotion on land - being able only to push its body forward across the ground ('belly-sliding'), although it can do this with some speed when required. It is, however, very agile in the water - the tail is well-developed and laterally flattened, and the rear feet possess extensive webbing.
Diet: The diet changes between juvenile and adult - the juveniles are well suited to deal with a variety of invertebrate prey such as insects, plus smaller vertebrates such as frogs. Adults, however, are primarily fish-eaters, for which their jaws and teeth are perfectly adapted - the thin shape gives the snout low resistance in water, which is suited to fast lateral snatching movements underwater; teeth are ideally suited for holding struggling prey such as slippery fish). Some of the larger gharials are more opportunistic and take larger prey, including mammals.
Females reach sexual maturity around 3 m in length (usually over 10 years old). Males guard a harem of several females. The mating period occurs for two months during November, December and into January. Nesting occurs in March, April and May (the dry season) where hole nests are dug into sand banks. Between 30 and 50 eggs are deposited into the hole before it is covered over carefully. The size of the eggs in gharials is the largest for any crocodilian species, weighing on average 160 grams. The juveniles emerge after 83 to 94 days, although the female has not been observed assisting the hatchlings this is perhaps because of the unsuitability of their jaws for carrying hatchlings, and their needle-sharp teeth. However, protection of the young does occur around the nesting area for some time after hatching.