It is well-known that the vehicle of Lord Ganesha is a small mouse. The images of Ganesha, seen in the ancient scriptures were without his vehicle. Ganesh Purana mentions about different incarnations of Lord Ganesha of which Mohotkata has a lion as his vehicle, Dhumraketu has a horse, Gajanana has the mouse and Mayuresvara has a peacock.
In western and central India, it is seen that a mouse is placed near Lord Ganesha’s feet as his vehicle and this custom dates back to seventh century. There is a story behind how a mouse became Lord Ganesha’s vehicle.
According to Ganesha Purana Krauncha, the musician-God, once accidentally stepped on the foot of Vamadeva muni. It happened in the court of Lord Indra and the angry sage cursed Krauncha to transform into a mouse. Krauncha became a very big mouse and it damaged everything on its way. The mouse reached Maharishi Parashar’s ashram and started destructive activities. Lord Ganesha was there at that time and wanted to teach Krauncha a lesson. He trapped the mouse using a rope and brought him to his feet. Thus, as a punishment, Krauncha, in the form of a mouse became Lord Ganesha’s vehicle.