Snakes fascinate. They repel. Some pose a danger. Most are harmless. And whether they are seen as slimy creatures or colorful curiosities, snakes play important environmental roles in the fragile ecosystems of the nation's wildlife areas. Snakes have found a place in religion and rituals as a symbol of worship. But, our first reaction on seeing a snake varies from panic, shock, to intense fear and thought to exterminate it. Most of the fear about snakes prevails due to the presence of venom. Snakes and their venoms have fascinated mankind since time immemorial. Snakes are elongated, limbless, flexible reptiles. Their body shape depends on the habitat in which they live. Aquatic snakes usually have a flattened body; those living in trees are long and slender with a prehensile tail while burrowing snakes tend to be compact. Snakes diet includs termites, rodents, birds, frogs, small deer and other reptiles. To keep prey from escaping, snakes have rear- facing teeth that hold their prey in their mouths. Venomous snakes inject their prey with venom, while constrictors squeeze their prey. Snakes are first thought to have evolved some 100-150 million years ago. Biologically, these ''limbless tetrapods'' are highly spec ialised and remarkably diverse, inhabiting all major ecosystems outside of the polar regions (they are not found in Arctic, New Zealand and Ireland (Deoras, 1965)) and representing the most common predators of other vertebrates (Green, 1997). Modern snakes are divided into three superfamilies, the Scolecophidia, the Henophidia and the Caenophidia. The Scolecophidia are all burrowing snakes with primitive characteristics such as the presence of pelvic vestiges (Jacob et al., 1998). The Henophidia contains several families that show a transition from primitive forms, represented by the family Aniliidae, which still possess pelvic vestiges, to the more advanced Achrochordidae that are more similar to the Caenophidia. The most highly evolved snakes are represented in the Caenophidia superfamily; these include the families Colubridae, Elapidae and Viperidae from whose ranks all the venomous species arise (Heise et al., 1995; Vidal and Hedges, 2002; Fry et al., 2006).
