The festival, beginning on the first day of the waning moon in the month of Bhadra as per the lunar calendar, lasts for a week.
During this time-honored tradition, people of all ages in the guise of cows and lunatics go around the city, wearing odd costumes to commemorate those who died during the past year. The bereaved families offer fruits, bread, beaten rice, curd and money to those participating in the procession including the cows.
As the saying goes, the festival derives its name from the religious belief that the deceased, during their journey to heaven, crosses a legendary river by grabbing the tail of a cow.
This festival is believed to have started during the reign of King Pratap Malla, who, in a bid to console his queen, much grieved at the death of her son in a smallpox epidemic, ordered his people to organize humour and satire programmes in various comic postures.
The tradition has been continued in the form of the Gaijatra festival during which people also give vent to pent-up feelings towards social and political anomalies, human follies and other contemporary affairs through comic skits, cartoons and the like.
Newspapers and magazines also bring out special humour and satire supplements to mark the occasion.