Snakes primarily represents rebirth, death and mortality, due to its casting of its skin and being symbolically "reborn".
The worship of snakes has been a very ancient tradition in India. According to Hindu mythology, the the serpent deities are semi-divine beings who descended from sage Kashyapa and Kadru. They live in the subterranean world of Nagaloka ruled by Ananta with Bhogavathi as its capital. They act as guardians of subterranean treasures such as gems, precious stones and minerals. Known for their quick temper, wisdom, skill and magical powers, they are depicted in Hindu iconography with a lower snake body covered by bejeweled garments and a human head adorned by three to seven cobra hoods. The snake deities are charming personalities, who can bewitch human beings with their grace and beauty. Garuda, the celestial bird and vehicle of Vishnu, is their cousin with whom they have an eternal enmity.
In certain parts of southern India, the serpent deities are associated with fertility and tree worship. Women, desiring offspring, worship snake stones having the images of a snake goddess carrying two offspring in her arms. The stones are installed under either a pipal or a neem tree after keeping them submerged under water for six months and worshipped with flowers and vermilion.
Prominent serpent deities include Ananta, Kaliya and Vasuki. Ananta is the king of the serpent world. Kaliya was a five headed serpent who was subdued by Lord Krishna after a prolonged fight. Vasuki was a giant serpent who helped both gods and demons in the churning of the oceans for the nectar of immortality.
The serpent deities constitute an important aspect of Hinduism even today. Devout men and women in the rural areas of both northern and southern India worship them with milk, incense and flowers, seeking their help and grace. In some parts of the country killing a snake is a bad karma and a bad omen. People avoid killing cobras because of the belief that they can recognize their attackers and take revenge. If a snake, or a cobra, is killed by an accident, it is customary to perform certain rites before cremating or burying it to avoid retribution from the serpent deities.