Reptiles of Sri Lanka

Reptiles, the class Reptilia, are an evolutionary grade of animals, comprising today's turtles, crocodilians, snakes, lizards and tuatara, their extinct relatives, and some of the extinct ancestors of mammals. Due to their evolutionary history and the diversity of extinct forms, the validity of the class is not universally supported in scientific circles, though in practice, it remains in use by some biologists and more laymen, especially in mass media. The study of reptiles, historically combined with that of amphibians, is called herpetology.

The earliest known reptiles originated around 315 million years ago during the Carboniferous period, having evolved from advanced reptile-like amphibians that became increasingly adapted to life on dry land. Some early examples include the lizard-like Hylonomus, Casineria and possibly Westlothiana, although the latter may be an advanced land-dwelling amphibian. In addition to the living reptiles, there are many diverse groups that are now extinct, in some cases due to mass extinction events. In particular, the K–Pg extinction wiped out the pterosaurs, plesiosaurs, ornithischians, and sauropods, as well as many species of theropods (e.g. tyrannosaurs and dromaeosaurids), crocodyliforms, and squamates (e.g. mosasaurids).

Modern reptiles inhabit every continent with the exception of Antarctica. Several living subgroups are recognized:

1. Testudines (turtles, terrapins and tortoises): approximately 400 species

2. Sphenodontia (tuatara from New Zealand): 1 species

3. Squamata (lizards, snakes, and worm lizards): over 9,600 species

4. Crocodilia (crocodiles, gavials, caimans, and alligators): 25 species

Sri Lanka is a tropical island close to the southern tip of India. The reptile fauna within the country is second only to bird diversity when comparing with number of species. Although snakes are characterized by loss of limbs and of eyelids, several lizards share one of these characteristics, and the relationships of snakes lie with lizards. There are 103 species of snakes found in Sri Lanka. Out of this 103, 48 species are endemic with 8 endemic subspecies. Lizards are generally recognizable from their limbs from snakes, but a few skinks, have lost their limbs through evolution. Most lizards feed on insects or other invertebrates. 

The monitor lizards, when adult, capable of subduing and eating small to medium sized vertebrates. Several groups of lizards, including Skinks, and Geckos, are capable of automising their tails; that is, when threatened, they can willingly shed their tails, growing a new one in time. The regenerated tail is never the same as the one lost, and generally lacks ornamentation, shape and color of the original tail. There are 42 species of geckos found in Sri Lanka, where 31 species with 3 subspecies are endemic to the island. 18 species of agamid lizards found with 15 endemic species, out of those 18. Out of 31 skink species, 24 species and 1 subspecies is endemic to Sri Lanka. 2 snake-eyed lizards, 2 monitor lizards, and 1 chameleon species are found. 2 species of crocodiles occur in Sri Lanka. They are heavy build, water-dwelling species, bearing scales and large heads. 

The Mugger Crocodile is a hole-nester and Saltwater Crocodile is a mound-nester. Turtles and tortoises complete the reptile fauna of Sri Lanka. Island is home to 3 species of non-marine species. Also out of world's 8 marine turtle species, 5 species visit the island for breeding. Total of 9 testudines are found in the island.