Pictures and idols of Lord Shiva depict him wearing snakes (cobra) prominently around his neck. Snake is known as ‘Nag’ or Naga and they hold a special place in Hindu religion. Snakes are worshipped in Hinduism. The snakes found on the body of Lord Shiva are considered to be his ornaments. The snake around Shiva’s neck symbolically represents the ego which ones mastered can be worn as an ornament. Coiled serpents also signify that Shiva is the master of time and energy.
Images of snakes are often depicted as coiled around the Linga (Shivling). A five-headed snake forms a canopy over the Lingam. Snakes serve Shiva as his sacred thread, necklace, bracelets, bowstring and are occasionally found on his clothes.
There are numerous symbolism attached to the snakes on Shiva. In some case, the snake around his neck symbolize the endless cycle of life and death. The other snakes found on him including in the form of girdle, armlets symbolize the eternal revolution of ages and the successive dissolution and regeneration.
There are numerous stories regarding Shiva’s association with serpents in the Puranas. Shiva is also worshipped as Nagesh at the Nageshwar Temple near Dwarka in Gujarat, which is also one among the 12 Jyotrilingas.
Snakes are said to bear rubies or diamonds (mani) on their heads, and the jeweled heads of cobras serve as lover’s lamps for Shiva and Parvati.
The most famous association of Lord Shiva with snake is during the churning of the ocean (Samdura Manthanam). Shiva drinks the poison halahala that came out of snake Vasuki, who was used as the rope in the churning. The blue throated Shiva or Nilakantha is the result of swallowing the snake poison.
According to another legend, at the time of their marriage, Goddess Parvati asked Shiva what ornaments he had brought for her. Shiva then gathered all the poisonous things in the world and made ornaments from them. Thus snakes became different ornaments. This episode is found in the Skanda Purana. Shiva making ornaments from serpents is also mentioned in the Padma Purana and the Matsya Purana.