The third day of the first lunar month was believed to be the day when daughters of rats were married so people would go to bed early for the fear of interrupting them. If rats were interrupted, crops would be ruined by them.

The origin of Pig Day originated from ancient legends in the Qin and Han Dynasties that people believed that Nv Wa created roosters on the first day of the first lunar month, dogs on the second day, pigs on the third day, sheep on the fourth day, cows on the fifth day, horses on the sixth day and human on the seventh day.