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The following points highlight the top twenty two types of reptiles. The types are: 1. Geckos (Family Geckonidae) 2. Draco (Family Agamidae) 3. Varanus (Family Varanidae) 4. Uromastix (Family Agamidae) 5. Iguana (Family Iguanidae) 6. Phrynosoma (Family Phrynosomatidae) 7. Chameleon (Family Chamaeleonidae) 8. Heloderma (Family Helodermatidae) 9. Slow Worms and Glass Snakes (Family Anguidae) and Others.
Type # 1. Geckos (Family Geckonidae):
Geckos are represented by more than 300 species and are denizens in all the warmer parts of the world. In India they are represented by two species: Gecko gecko—is about 30 cm in length and the tail is shorter than head and body. The body is spotted with red or orange colour. The toes bear undivided adhesive papillae (Fig. 8.34B). The name “Gecko” is derived from the clicking sounds of the tongue.
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Habit and Habitat:
It lives in the trees of the jungles and also in the houses. They are aggressive in nature and bite if molested. Most geckos are oviparous and lay their eggs in covered places. They prey on insects, rats and even small snakes. They are nocturnal prowlers.
Type # 2. Draco (Family Agamidae):
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They are represented by about 15 species and are inhabitants of South-East Asia and Indonesia. Small lizards with long tail having a parachute web on each side of the body are supported by 4 or 5 pairs of long hinder ribs (Fig. 8.34E). These are carried in folded condition and spread out when the lizard takes a long leap.
Habit and Habitat:
They devour tree ants. The female Draco lays 2-5 eggs at a time.
The well-known species is Draco volans which ranges from the Philippines, Malaysia to Indonesia and is identified by yellow to orange red wings and bluish underside with black spots.
Type # 3. Varanus (Family Varanidae):
Varanus or monitors are the largest members of the living lizards. They are recognised by mobile head, long neck and a longer compressed tail. They also possess pleurodont teeth and a long protrusible bifid tongue. Colour of the body depends on variable habitable grounds. The tail is rounded in terrestrial forms and compressed in aquatic ones and it is used as a defence organ.
Habit and Habitat:
They are good climbers and swift runners also. The female lays about 15 to 30 eggs in termite mounds or in secluded places. They are sighted in burrows, tree holes and in under-logs. Their food includes fishes, amphibians, lizards, snakes, birds and small mammals, specially mouse and rats. They are fond of eggs. They are found in Asia, northern parts of Africa and Australia.
The World’s largest lizard is Komodo Dragon (V. komodoensis) and is about over 3m in length. They are found in some islands of Sunda Archipelago.
Type # 4. Uromastix (Family Agamidae):
They are recognised by flattened body and the tail with whorls of spines. They are about 350 mm in length and in colour it is yellow brown above and whitish below. The throat is often furnished with black spots and with some transverse loose folds of the skin.
Habit and Habitat:
It is herbivorous and mainly observed living on the stem of Capparis decidua which grows in and around its habitat. Besides they take flowers of Tephrosia purpurea and fruits of Capparis. Instead of flowers, stems, and fruits they consume ants, termites and grasshoppers. It is very timid and docile but sometimes they become ferocious. They are quite tolerant in mid-hot day. The female lays 15 to 20 eggs at a time.
Another member of Agamidae is spiny devil of Australia. The spiny devil (Moloch horridus, Fig. 8.35A) is a dorsoventrally flattened spiny horned lizard. It lives in the Australian desert. It has a hygroscopic skin.
Type # 5. Iguana (Family Iguanidae):
Iguanas are recognised by larger size (about 90 cm in length), dorsal and caudal cresto and spines and pleurodont type of teeth. There are about 400 species of Iguanidae, confined to the North America, Central America, South America, Galapagos Islands, Bahamas and Cuba.
Iguana iguana and I. delicatissima are true iguanas live in the forests of tropical America. The famous Galapagos Land Iguana, Conolophus subcristalus, is found in Narborough, Albemarle, Seymour and Plazas. They are yellowish in colour with patches of rusty-orange. The Marine Iguana, Amblyrhynchus cristatus, is found along the rocky shores of Galapagos Islands.
Habit and Habitat:
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The iguanas are mainly insectivorous, but some are herbivorous and omnivorous. They have adapted in different modes of life terrestrial, arboreal, fossorial, semiaquatic or even semi-marine. The marine iguana can search its food under water and can swim in sea, keeping its head above the water. The iguanas of Galapogos Islands are on the verge of extinction.
Type # 6. Phrynosoma (Family Phrynosomatidae):
They are denizens of the deserts of Mexico and in the South-western United States. About fifteen species occur in this region and are identified by spikes on the head and back. The body colour depends on the surroundings.
The yellow colour is in sandy area, white to brick red in Grand Canyon of U.S.A. They use tongue to catch insects like toads. The horned toads shoot tears when they are excited. They are ovoviviparous, and only iguanids that give birth to the young’s.
Type # 7. Chameleon (Family Chamaeleonidae):
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Chameleons are recognised by triangular head with a pointed crest above and a prehensile tail. Both fore and hind limbs have two digits opposed to the other three, like thumb and fingers of the primates. The sticky club- shaped tongue may extend to the size of the body during catching insects. Bell (1990) has calculated the maximum velocity of the tongue to be about 4.25 m/s.
Eyes can be moved independently. They have a remarkable power in changing the colour and this is controlled by an autonomic nervous system. The change of colour may be in response of light, heat or emotion. They are arboreal and insectivorous.
A single female may lay about 30 eggs in holes. About eighty species are found in Africa, Madagascar, Europe and India. Only single Indian species, Chamaeteon (= Chamaeleo) zeylanicus, occurs in the wooded districts of Indian peninsula.
Type # 8. Heloderma (Family Helodermatidae):
Commonly called Gila Monster and Beaded Lizards. They inhabit in the deserts of Mexico, Nevada, Arizona and Utah of U.S.A. Two species are known—Gila Monster (Heloderma suspectum) and the Beaded Lizard (H. horridum). They are about 30 cm in length and brightly coloured with black spots. They are the only poisonous lizard but bite is not lethal to man. The food includes eggs of birds and young mammals.
Type # 9. Slow Worms and Glass Snakes (Family Anguidae) [Fig. 8.35C]:
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Limbless, elongated body, with a forked tongue, movable eyelids and an ear opening probe are its identity as a lizard. The Glass snake (Ophisaurus) (Fig. 8.35C) is restricted to South-Eastern Europe, North America, Southwest Asia and India.
Only Indian species, Ophisaurus gracilis, occurs in Eastern Himalayas. Its body colour is dark brown above and light under-parts. It has a brittle tail and a black tongue. It is nocturnal and insectivorous. They are the only limbless lizard in India.
The slow worm (Anguis fragilis) is the limbless lizard but possesses the vestiges of pectoral and pelvic girdles. It reaches up to 50 cm in length. It is found in Europe, Western Asia and Algeria. Mainly nocturnal is found in humid places of grasslands and forests. It devours worms, caterpillars and slugs.
Type # 10. Blind Snakes (Family Typhlopidae):
They have rounded body with smooth shining slippery scales. The eyes are hidden beneath the head scales and their teeth are absent in the lower jaw. Small body with blunt tail. Feed on ants and termites. About 200 species all over world of which 14 are Indian.
They live in under logs, leaves, wet forests and in the gardens. Some Indian species are common worm snake (Ramphotyphlops braminus), Slender worm snake (Typhlops por-rectus) and Gunther’s worm snake (T. psammeces), etc.
Type # 11. Shield Tailed Snakes (Family Uropeltidae):
Popularly called Shield Tailed Snakes or Rough Tails. Slender and pointed heads with short, blunt and rough tails, and vestigial eyes. Abdomen is beautifully coloured. They are expert burrowers. Non-poisonous and the female gives birth to 9 young’s.
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They are confined to the forests of cold mountainous areas of South-west India and Sri Lanka. 44 species are known of which 33 are Indian. Some examples are Pied-belly shield tail uropeltid (Melanophidium punctatum), Madurai Shield tail (Platyplectrurus madurensis) and Cochin Shield tail (Uropeltis nitidus), etc.
Type # 12. Sunbeam Snakes (Family Xenopeltidae):
They have cylindrical body, a short tail and overlapping irridescent scales. The snake is nocturnal and highly burrower, and lives under logs, stones and also in gardens. It feeds on amphibians, snakes and small mammals. Single species (Xenopeltis unicolor) has been recorded from South-East Asia including Malay Islands. In India it has been recorded from Andaman Islands.
Type # 13. Boa, Pythons and Giant Anaconda (Fam. Boidae and Pythonicae):
The Giant Anaconda (Eunectes murinus) or Water Boa is one of the largest living non- poisonous snakes belonging to the Family Pythonidae. It may grow up to a length of over 9 m but authenticated reports claim 7.5 m or less.
Its colour is olive green back with round black spots along its length. The female gives birth to 30 young’s. The name itself is said to come from the Tamil words. Anai for elephant and kolra for killer. They prey on birds and mammals. It is found in the northern parts of S. America, mainly in the Amazon and Orinoco basins.
The word Boa has its origin from Latin. Boa means ‘water snake’ in Latin, but not all boas live in water. Boas include non- poisonous S. American snake of genus Boa and old world python. The word python has its origin from Greek-Puthon, a huge serpent.
In Greek mythology, Apollo, the name of sun- god, killed ‘puthon’ near Delphi for harassing his mother and its genus is Python. Python means a large non-poisonous snake which kills its prey by compression.
Though Boa and Pythons are similar in appearance but they are placed in different families for their differences in skull structure and mode of reproduction. In Boidae, (he supra-orbital bone and pre-maxillary teeth are absent. Boas are viviparous. But in Pythonidae supra-orbital bone is present and the females lay eggs.
The Common Sand Boa (Eryx conicus) is common throughout India. Body colour varies dark brown to yellowish white with irregular blotches down the back. It is nocturnal and feeds on rodents. The female gives birth to about 6-10 living youngs.
The Red Sand Boa (Eryx johnii) is common in the dried parts of India. Body colour varies reddish brown to yellowish. It is often called “two headed snakes” by the snake charmers because its tail is so blunt and rounded that it appears another head of the snake. It is nocturnal and good burrower. The female gives birth to 6-8 living young’s around June. Both are non- poisonous and viviparous Indian species.
One of the well-known species is the Boa constrictor (Constrictor constrictor), known from Tropical America, grows about 12 feet in length. In both families (Fam. Boidae and Pythonidae), the vestiges of the hind limbs terminate in a claw like spur.
Largest members of the living snakes belong to the family Pythonidae (e.g., Python and Anaconda). They are inhabitants of the old world including Australia except Madagascar. Two species occur in India. Indian Rock Python (Python molurus) grows about over 9 metres in length and inhabits in arid scrub jungles, rain forests and in estuarine mangrove forests.
They are nocturnal in habit, and their food includes rodents, jackels, wild pigs and deers. The female lays 100 eggs in between March and June. Another species is Reticulated Python (Python reticulatus) which reaches up to 10 metres, probably the largest snake in the world and is found in the forests of Nicobar Islands and also in South-East Asia.
Type # 14. Vipers (Family Viperidae):
The word ‘Viper’ has its origin either from French Vipere or from Latin Vipera, and is called for its viviparous nature. The rattle snakes, copperheads, water moccasins (Agkistrodon piscivorus), and tropical American vipers (Bothrops) are known as Pit vipers.
They are called pit vipers because of the presence of facial or loreal pits on the sides of the head between eyes and the nostrils. These pits act as infrared receptors or thermo receptors.
These pits are lined by epitheliums which contain hair cells that become sensitive to infrared or thermal radiation. Sensory nerve endings are suspended in this membrane halfway between the bottom and top of the pit. The nerve endings warm up rapidly and can detect the warm blooded animals or other animals within a range of several feet.
During the day time the rodents and birds can be detected by the pits. Changes of 0.003°C can be detected by pit vipers. These two sensory pits contain highly vascular tissues and membranes, lined by membranes that contain hair cells and vascularized tissue.
About 60 species of Pit Vipers occur in North and S. America and Southern half of Asia of which 16 species under two genera, inhabit in India. The genus Agkistrodon includes Himalayan pit viper (A. himalayanus) and Hump nosed pit viper (A. hypnale) and the genus Trimeresurus includes rest of the species (e.g., Bamboo pit viper (T. gramineus) and Jerdon’s Pit viper (A. jerdoni), etc.
The famous Rattle Snake is included in the subfamily Crotalinae under Viperidae. About 26 species under Crotalinae ranges from N. America to S. America. Large Rattle Snakes (Crotalus durissus) attain a length of about 2.5 m and is the common species of South-eastern North America. C. horridus is the common Rattle Snake of the United States.
True vipers inhabit in Asia, Europe and Africa. They are oviparous or viviparous. In India, true vipers are represented by 3 species under two genera. The genus Vipera includes Russell’s viper (Vipera russellii, Fig. 8.37A) and Levantin viper (V. lebetina). Levantine vipers occur in Kashmir. The other genus Echis includes Saw Scaled Viper (Echis carinatus).
The members of viperidae are recognised by triangular heads, narrow necks and small scales on the head. Vipera russelli is recognised by about 25-30 reddish brown oval spots on the body. It is nocturnal and slow mover. It hides in rock crevices, brick heaps and hay stacks. It feeds on frogs, toads, birds and small mammals, especially rats.
A female may give birth to 60 young’s during mid summer. With its long, movable fangs, it can strike but not to bite. The pit vipers possess pits between nostril and eye on each side. These pits are very sensitive to the temperatures and help the snake in detection of warm-blooded prey in their surroundings.
Type # 15. Cobras, Kraits and Mambas (Family Elapidae):
The Cobras (Fig. 8.37B) are recognised by their expanded hoods and markings on their hoods in some species. The word cobra is from latin word ‘Colubra’, means snake. In English the name ‘Cobra’ is given to a snake which possesses hood with marks on it.
In Portuguese ‘Cobra’ means a snake with a hood. In Hindi it is called ‘Nag’ or ‘Naga’. In West Bengal it is called “Gokhura”. In Tamil Nadu and Andhra Pradesh it is called ‘Nallu Pambu’ and in Karnataka it is ‘Nagarahavu’. The poisonous hooded Indian and African snake of genus Naja is also called Cobra.
They are highly poisonous and bear poison fangs in front of the jaw bone.
Generally nocturnal and foods consist of frogs, toads, rats and even other small snakes. The venom is neurotoxic.
The Egyptian cobra (Naja huje) is perhaps the snake which was used by Cleopetra to take her life.
The largest Spitting Cobra in South Africa is Black Necked Spitting Cobra (Naja nigricollis), grows over 2.5 metres in length and can eject their venom to the enemy’s eyes at distances over 3 metres.
Spitting Cobras do not ‘spit’ in true sense of word. Their venom is ejected forcibly when the snake exerts muscular pressure excessively on the venom gland, resulting venom ejection of as a spray from the fangs.
Indo-Malayan King cobra or Hamadryad, Ophiophagus ( = Naja) hannah (Fig. 8.37C), is the largest of the cobra and longest of the world’s poisonous snakes. It is the most poisonous and dangerous snake in the world. It grows over 6 m in length. The colour of the adult is faint black with or without bands.
It is the only snake in the world that builds its nest on trees and takes care of the young’s. Its food includes other snakes. The king cobra is not eater of Python. The king cobras are not usually aggressive but if injured, the snake may charge with open mouth emitting a deep growl. The poison gland contains 6.5 cc poison and a single strike is enough to kill an adult elephant.
They are found in the mangrove forests of Bengal (Sundarban), Orissa, Assam, Western Ghats and Andaman Islands in India. The word ‘mamba’ is from Julu (S. Africa). The word ‘imamba’ has become mamba. The mamba is a highly venomous South African snake of genus Dendroaspis.
African black mambas (Dendroaspis angusticeps) are tree dwellers and one of the most poisonous snakes in the world and can attack the man with unbelievable speed and ferocity. Their venom can kill a man within 10 to 20 minutes. The black mamba (D. polylepis) is the fastest of all snakes with an accurate recorded speed 7 mph and about 15 mph may be possible in short bursts.
The Krait has its origin from Hindi — ‘Karait’. The krait is a highly poisonous East Asian snake of genus Bungarus.
The common krait (Bungarus caeruleus) is recognised by steel blue in colour and there are about 40 cross-bars in 2/3 posterior part of the body. In Maharashtra, the cross-bars are lacking, only the white spots on the dorsal side. They are nocturnal and consume mice, olive keelback snake (Atretium schistosum) and striped keel-back (Amphiesma stolata) and smaller fellow kraits.
The female lays about 8-10 eggs from March to May. They are highly poisonous and venom is neurotoxic. Krait bite (common krait and Banded krait) deaths constitute the second highest fatality in South-east Asia, especially in India and its adjoining countries.
Highest number of bites takes place in winter nights, especially at late nights. The snake is found all over India. In W. Bengal, the maximum number of bites takes place in rainy season nights.
The banded krait (Bungarus fasciatus, Fig. 8.39) is identified with triangular shaped body, alternating black and yellow bands all over the body and blunt tail. The animal eats mice and other snakes. It is oviparous.
The venom is neurotoxic. It is found in W. Bengal, Bihar, Orissa, A.P., M.P. and Assam. The species of kraits are found in India of which the venom of B. caeruleus is potentially most dangerous in S.E. Asia. It is second most poisonous snake in the world.
Type # 16. Sea Snakes (Family Hydrophidae):
Recognised by their flattened body, oar- shaped tail and the position of nostrils on the top of the head. They can dive up to a depth of 100 metres and can stay underwater for about 8 hrs. Due to low metabolic rate, a larger lung capacity is compared with land snakes.
Skin respiration is one of the physiological adaptations of sea snakes in marine environment. Salt problem in the marine environment is solved by the salt gland which is the principal organ of salt excretion. The skin is impermeable to the passage of water.
They are found in the tropical parts of the Indian and Pacific oceans. Their diet includes small fishes especially eels. They are viviparous. All the members are venomous. The venom is neurotoxic and more powerful than that of cobra but the bite is seldom for the timid nature.
Hydrophis belcheri, the most venomous snake in the world is found in the Ashmore reef, in the Timor sea of North-west Australia and is recorded 100 times lethal as that of the Australian Taipan (Oxyuranus scutalathus).
Type # 17. Estuarine Crocodile (Family Crocodylidae):
Indian crocodile may measure 6 m. They are very common in the eastern coast of India. They are fierce reptiles and dangerous man-eaters.
Type # 18. Nile Crocodile (Family Crocodylidae):
They are the sacred crocodile of tropical Africa (Fig. 8.41 A). They exhibit a peculiar friendly partnership with little birds belonging to the genus Pluvianus which enter into the kept- open mouth of the animals and remove parasites, specially helminths, from the root of teeth.
Type # 19. Alligator (Family Alligatoridae):
This genus of crocodile is often confused with Indian crocodiles. Alligators (Fig. 8.41 B) are not found in India and they are strictly restricted to China and South America.
Type # 20. Gharial Cavialis Gangeticus (Family Gavialiidae):
Commonly known as ‘Gharial’ and occurs in the rivers of Burma and India, specially the Ganges, the Indus, the Brahmaputra, and the Mahanadi (Fig. 8.41 C). These are large crocodiles and may measure 6 m or above.
Though they are fish-eater and considered harmless to man, often ornaments have been encountered in their stomach. A display of ornaments obtained from the stomach of dead crocodiles may be seen in Calcutta Museum.
Type # 21. Green Turtle (Family Chelonidae):
C. mydas is an edible turtle. It is green in colour. It attains a length of about 1 m and weights between 150-175 kg. The carapace of chelone is depressed and the limbs are modified for swimming in water. The limb bones are flat and wide. The carpal and tarsal bones are fused and the digits remain embedded within the flipper. Claws are absent. Skull is of anapsid type.
Habit and Habitat:
Female Chelone lays eggs at night on the beaches of remote islands. Eggs are laid in two or three batches and at intervals of about a fortnight. Chelone is on the verge of extinction because of excessive killing.
Type # 22. Soft-shelled Turtle (Family Trionychidae):
It is a most widespread turtle. Popularly it is known as soft-shelled turtle. The carapace lacks scales and is covered by skin. The snout is elongated and ends in a small proboscis. The beak is horny and the lips are soft. Each limb bears three claws. The body length is less than a metre.
Habit and Habitat:
They are strictly aquatic and feed on fishes, frogs and molluscs. The females lay about twenty spherical eggs at a time and bury the eggs in sand some distance from water. The Indian species, Trionyx gangeticus, lives in Indian rivers.
