Nandi is a bull, which is said to be an attendant of Lord Shiva. This animal has some similarity with Vishnu`s Garuda. Originally, it was known by the name Nandikeshvara and it is said to have existed in human form as a rishi (sage), who belonged to Shiva`s attendants. He also acted sometimes acted as Shiva`s door-keeper.

According to the Puranas, Nandi achieved divine or semi-divine status in various ways. These include his recognition as another form of Shiva from whom, in some cases, his representations are sometimes almost impossible to differentiate. In the form of rishi, Nandi can be seen at the entrance to Shiva temples. But, he is seen in the form of a bull more frequently.

According to the legends, it is said that Prajapati Brahma gave the Nandi bull to Shiva or he took the form of a bull to represent Dharma and stood for the salvation of departed souls on the other side of death. The association of Lord Shiva with the Nandi bull can be due to his relationship with Rudra, who was sometimes referred to as a bull. This may have its roots in the mythology. Earlier, the bulls were found in ancient scriptures, which have contributed to the civilisations of different countries. The universal strength of Lord Shiva can be linked with his association with the Nandi bull.

The association of Nandi bull with fertility is explained by the custom of touching his testicles when worshippers enter a Shiva temple intending to offer prayers for an increase in the size of their family. Nandi is painted as pure white with a well rounded body, large brown eyes, heavy shoulders, shining coat and black tail. The lump of Nandi is drawn like the top of a snow-capped mountain and he should have a golden belt round his body and sharp horns with red points.