Saturday, July 2, 2011

Crocodiles Under Water and Type Crocodiles

The body is covered with a rough hide like skin, underlined by bony plates. The elongated snout terminates in a rather bulbous nose with the nostrils positioned on top so as to enable the crocodiles to breathe without difficultly when the body is submerged. The eyes, which are also placed high on the head, are well protected by the eyelids and a movable transparent membrane so that the vision is not affected under water.

Crocodiles
Crocodiles

 The throat is provided with a fleshy valve that would permit the crocodiles under water to pursue the prey, without the risk of drowning. The tail is highly muscular and propels the reptile through water easily. The colouration of the adults is rather dull, but the young ones are brightly coloured, with dark brown spots or bars on the back.

Crocodiles

The three species of crocodiles found in India are mugger (Crocodylus palustris), the salt water or estuarine crocodile (Crocodylus porosus), and the gharial or gavial (Gavialis gangeticus). Easy identification of gharial, mugger and salt waters crocodiles can be made with the shape of head and jaws The three crocodilians found in India may be easily identified: the gharial (right) has the thinnest jaws. The mugger (middle) has the broadest. The saltwater crocodile (left) has a longer snout than the mugger and no large scales behind its head.

Family Crocodillies :
- Salt Water Crocodile or Salt Water Crocodile Crocodylus porosus Schneider
- Marsh Crocodile Crocodylus palustris Lesson
Salt Water Crocodile Crocodylus porosus Schneider

Salt Water Crocodile
 The Salt Water Crocodile or estuarine crocodiles are recognized by longer muzzle and two prominent ridges running forward from the eyes and converging on the nose. The Salt Water Crocodile colour is dark olive green or brown or almost black above, and lemon yellow on the underside. The eye is yellow. It is really known to reach a length of 7 meters, although most specimens today are under 4.30 metres.

Salt Water crocodile
This Salt Water crocodile species is a truly seagoing reptile, which prefers mangrove swamps, deltas, estuaries and coasts as its habitats. It principally feeds upon fish and crustaceans, but also takes birds and mammals. The female lays from 40 to 60 eggs and buries them in to a mounded‐type nest. Incubations lasts from 75 to 90 days.

Marsh Crocodile Crocodylus palustris Lesson

Marsh Crocodile

Marsh Crocodile or Crocod ylus palustris is short and is devoid of any ridges. A square of four shields on the nape with four distinct scales between the large shield and the broad head are the most obvious features. The colour is olive or pale, with prominent dark spots in young, and black in adults. It may reach a length of 4 meters, but most specimens are under 3.25 meters.

Marsh Crocodile
 Although the species is called “Marsh Crocodile”, it is by no means restricted to marsh lands, but is also found in rivers, lakes and man‐made reservoirs, ponds or tanks. It is reported even from the Himalayan foothills and the salt lakes adjacent to estuarine area. Its principal food includes fish, frogs and crustaceans but occasionally turtles, birds and mammals.

In mangrove area, the reptiles like amphibians are occurring in different environments such as forest, land, water etc. Crocodiles are widely distributed in Asia, Africa, Madagascar, Australia, Papua New Guinea
and in North and South America. At present the estuarine crocodile is confined within India to parts of the east coast of mainland and the Andaman and Nicobar Islands. It is recorded outside India mainly from the coasts of Sri Lanka, Burma, Malaya and Indo‐China through the Malay Archipelago to the Philippines, Northern Australia, New Guinea and Solomon Islands.

The marsh crocodile is widely distributed in India although populations are fragmented and isolated. Its area of occurrence outside India includes Iran, Pakistan, Nepal, Bangladesh and Sri Lanka. Indopacific crocodiles Crocodylus porosus are abundant in the upper mangroves of the Kias river, Sabah, Malaysia. Small numbers are found in the Sundarbans where it has been depleted by hunting. In Orissa a population of 35 adults is found in the Bhitarkanika wild life sanctuary (Bustard and Choudhury, 1981). Populations are depleted in Andaman islands between 170 and 330.

The population in the Nicobar is reported to be healthy but no precise data are available (Choudhury and Bustard,1979). The Nicobar may be its last stronghold in India (Bagla and Menon, 1989). Breeding programmes are operated through the West Bengal Forest Department; the Orissa State Forest Department; and the Madras Crocodile Bank. Hatchlings are released in Bhtarkanika; in the project Tiger Reserve (Sundarbans); and in the Coringa Wildlife Sanctuary (Luxmoore et al., 1985). There is an urgent need for habitat protection and the species has received some protection in the Mahanadi
Delta (Scott, 1989).

Varanus Hydrosuarus and Psammosarus

Varanus sp. was reported from the mangroves of east coast of India (Kathiresan and Rajendran, 2000).
The name of “Monitor” bestowed upon these creatures has a curious origin, owing to a ridiculous etymological mistake. The Arabic term for lizard is “Ouaran”.

Varanus-dumerili

Varanus salvator

This has been wrongly taken to mean warning lizard, hence the Latin word‐Monitor. One of the many synonymous of this genus varanus are Hydrosuarus and Psammosarus.

Varanus cummingi
Varanus jobiensis-batanta
Varanus rudicolis

Many of the “Monitors” are semi‐aquatic, and others inhabit dry, sandy areas, while others are in well‐wooded localities. They are rapacious, taking whatever animals they can master according to their size, which in some species amounts to 6 to 7 feet.


Lizards India Reptile Species

Lizards are classified as sub‐order Sauria of the class reptilia. Lizards are characterized by a short body with four well‐developed limbs, a short, flat tongue and an external ear opening. Some limbless lizards which
have elongated bodies are snake‐like in appearance but they can be identified by their distinctive ear openings and movable eyelids, which are quite foreign to the prey and also as sensory organs. The ability to shed the tail and regenerate a new one in its place is possessed by geckos, lizards and snakes.

Lizards
Lizards

Most of the lizards can change colour, depending on the light, temperature and the mood of animal. Males are larger and brilliantly coloured than females. Lizards principally feeds on insects and small animals. Indian lizards range from a 5 cm long sting to 2.5m long water monitor (Varanus salvator). There are no venomous lizards in India.


Lizards

Most commonly available lizards were Varanus, Chameleon and Calotes. Calotes are easily identified by colouration, while Chameleon with green colour and change its colour according to the environment. Tail end is always coiled. Varanus can be identified with the brown colour on the dorsal side and arranged bands.

Lepidochelys Olivacea Under Water Sea Turtle

Lepidochelys Olivacea Sea Turtle

Lepidochelys Olivacea is Carapace semicircular in outline, depressed, its width‐about 90% of the length. Head small (about 22%of carapace length) with 2 pairs of prefrontal scutes and a horny beak which may be finely serrated. Usually more than 5 pairs (sometime even 7) of lateral scutes on carapace, anterior pair touching the precentral scutes; 4 pairs of inframarginal scutes, each perforated by a pore towards its hind margin; adults with only one visible claw on each flipper.

Lepidochelys Olivacea

Lepidochelys Olivacea
Upper side is olive brown; underside yellowish white. Lepidochelys Olivacea Eggs are white, spherical, about 3.9 cm in diameter and 33g in weight.

Lepidochelys olivaceae is most common turtle in India and the main population occurs in the Bay of Bengal. About 3 lakhs nest in Orissa, which have two important sights in the north east as Gahirmatha within the Bhitarkanika wildlife sanctuary and Nadiakhia Muhana and Akasa muhana. Mass nesting at Gahirmatha occurs annually, mainly around Ekkula where a total of 5 lakhs have been estimated to nest. Small
numbers nest at any size elsewhere around the coast including the Gulf of Kutch, Sourastra, Peninsular, Gulf of Khambhat, Piraton island, and along the entire east coast, including near Madras and eastward area of
Vedaranayam swamp, the Krishna delta, Sundarbans, Kanak island, Bakha beach, Lothian mechua syamarysayal and on the Andaman, and Nicobar and Lakhadweep islands.

Cheloniidae Sea Turtle

Cheloniidae, Chelonia mydas Agassizii

Cheloniidae

Shell, Cheloniidae Sea Turtle head and flippers were covered with horny lamellae (scutes); horny beak never ‘W’ shaped when viewed from the front; flippers with 1 or 2 claws. Carapace oval, depressed, its width about 88% of the total length. Head small (about 20% of carapace length), with a single pair of prefrontal scutes; edge of lower jaw coarsely toothed, that of upper jaw with strong ridges on inner surface.

Cheloniidae
Cheloniidae

Four pairs of lateral scutes on carapace, anterior pairs not touching the precentral scute; 4 pairs of inframarginal scutes on plastron; a single claws on each side. Upper side dark olive brown or black, scutes of carapace shiny with radiating yellow, green and black spots; underside pale grey or whitish. Eggs are white, spherical, about 4.5 cm in diameter, and 38 g in weight. It is interesting to note these turtles browse the leaves of Avicennia and the fruits of mangroves.

Dermochelidae and Dermochelys Coriacea Family Turtles Species

Dermochelidae-Horny skin smooth, scute; carapace black with 7 narrow longitudinal ridge, white dotted plastron with 5 longitudinal ridge; upper jaw with a well‐defined cusp on each side, giving the horny beak a ‘W’ shaped appearance when viewed from the front; large flipper without claws, the anterior pair much bigger, the posterior broadly connected with the tail by a web in adults.

Dermochelidae

Dermochelys Coriacea

Dermochelys Coriacea is Body is depressed and covered by a smooth leathery skin lacking lamellae or scute. Head is small, ending in a horny beak with a well defined cusp at each side of upper jaw and a central cusp on lower jaw (beak ‘W’‐shaped when viewed from the front). Seven longitudinal ridges (including the outer or lateral pair) are on carapace and 5 on plastron. Flipper is very large, without claws.

Dermochelys-Coriacea

 Upper side is dark brown to almost black; whitish spots on neck, increasing in number on the ventral and caudal areas. Egg are white, spherical, normally about 5.5 cm in diameter and 75g in weight; the proportion of unfertilized small eggs may often be high.

Dermochelys coriacea is the least abundant sea turtle; it is present from Natal to the Tanzanian border, on Oman and the “Gulf” and on the southwest coast of India and Sri Lanka. Predominantly pelagic and
highly migratory ones are usually found in the open sea, but approaching the land seasonally. The most important nesting beaches are found on the eastern part of the Malayan peninsula (Trengganu).

Turtles in 22 Species of Auatic Turtles

Turtles
 The varied usage of the words “turtle” and “tortoise” in English has given use to much confusion. In proper usage, tortoise refers to the strictly land dwellers with elephant like stubly feet, “turtles” are the aquatic forms inhabiting the sea, rivers and ponds with either flippers or webbed toes and “terrapins” are the hard shelled edible freshwater tortoise. Turtles are toothless but they have a beak with horney sheaths.



Turtles
 They chew their food only to reduce in for swallowing. They are omnivorous, and like other reptiles, can survive without food for months. All turtles nest on land. Their maximum life span is 100 years or a little more but it is certain that they live longer than any other vertebrates including man. They vary greatly in size, from 72 cm to the 1.8 m long. Five kinds of exclusively sea living turtles, 22 species of aquatic turtles and / or tortoise, and 4 varieties of land tortoise are found in India.

Sea Turtles

Key to Genera of Turtle
1a. Horny scutes on carapace imbricated (overlapping in all except in all very old specimens‐‐Eretmochelys
1b. Horny scutes on carapace juxtaposed (not imbricated)
2a. Four pairs of lateral (coastal) scutes on carapace; edge of lower jaw coarsely toothed; a single pair of prefrontal scutes; a single pair of claws on flippers‐‐Chelonia
2b. Five or more pairs of lateral (coastal) scutes on carapace; 2 claws on each flipper
3a. Four pairs of inframarginal scutes on the bridge of the plastron, each with a small perforation or pore toward their hind margin; carapace semicircular‐Lepidochelys
3b. Three pairs of enlarged inframarginal scutes without pores on the bridge of the plastron; carapace heart shaped‐Caretta.

Chelonia mydas exists throughout southward areas to 25o, especially around islands in the Mozambique Channel, Gulf of Oman, the ‘Gulf’ and the Gulf of Aden. Other subspecies of green turtle are found in the
Atlantic and in the eastern and Central Pacific oceans. The main nesting areas are located on the islands of Mauritus, Europe, Aldaba, Comoro and Seychelles. The most important nesting areas are found on the
coasts of Pakistan and slightly south of the west Indian borders; other important nesting beaches exist in northern Mozambique and on the southwest coast of Madagascar. The major nesting beaches for this
species are outside the area, on the northeast coast of India, Orissa district.

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