Reptiles are termed as cold blooded animals as their body temperature varies with the outside temperature whereas birds and mammals which have a constant body temperature -- and therefore are known as warm blooded.

Indian reptiles come in a wide size range. For instance, the marine estuarine crocodile has a length that exceeds seven metres and the gecko is less than 100 mm in length.

All snakes and geckos, among lizards, do not have eyelids. Instead, they have a permanent transparent cover that is changed every time the skin is shed.

Lizards and snakes are the only reptiles that can climb trees and many are arboreal. The chamelcon and some gockos are particularly well adapted for arboreal life. A particular gecko, lizard and snake have the ability to glide through air.

The sense of hearing is well developed in crocodiles which are provided with an external car flap to shut off the tympanic cavity when under water. Snakes and some burrowing lizards lack cars and their hearing is mainly restricted to vibrations.

In snakes, the forked tongue has lost the traditional function of the tongue as an organ of taste and has become a carrier of scent particles. The snake smells its food and its enemies with its flickering tongue.

Pythons and vipers have a remarkable sense organ present on the snout as sensory pits. These pits are very sensitive to heart ration and assist in the location and capture of warm-blooded prey.

Majority of reptiles are carnivores. Insects form the main food of a large number of reputles. A few reptiles such as the land tortoises, the marine green turtle and the spiny-tailed lizards are totally herbivores.

Majority of reptiles lay eggs which are usually buried in pits in the soil for incubation. The saltwater crocodile and the king cobra lay eggs in specially constructed nests above ground. Females of many reptiles have the ability to store sperm and fertile eggs which may be laid even three to four years after separation from the male!