It may be noted that the golden mouse is the smallest mammal in whom the relationship of the mother and child is more apparent. Elephant is the biggest among the land mammals and man occupies the top most position between these two mammals from the point of view of this physical and mental evolution. It may be noted that the human part of the form in Ganesha image is in between his elephant head and the mouse, his mount.
There is no doubt that there is a meaningful and mystic design for the mouse to come into the figure of Ganesha with an elephant head on a human body. We have to decipher the design and the meaning behind it.

In the Thaithiriya Brahmana there is a reference about a feud between GOD Agni (Fire) and other Gods. Agni disappeared into the earth assuming the form of a mouse. Later on when there was a truce among the parties, this mouse by common consent was presented to Shiva. Shiva energised by the possession of this mouse generated Karthikeya popularly known as Subramanya in South India. After the generation of Karthikeya Shiva made a present of the mouse to his elder son, Ganesha, who was for a long time without a mount as could be seen in the early Gupta period works of art.

The reference in the Thaithiriya Brahmana that Agni disappeared into the earth assuming the form of a mouse is very significant. Agni in Vedic literature according to Aurobindo is indicative of "Truth conscious seer - will", "Divine energism" and the "force of Rudra", Agni is also one of the Vedic Gods.

"Indrum, Mitram Varunam Agnim ahuratho divyah Suparno Garuthman Ekam sat Vipra bahudha vadantha. Agnim Yamam Matarisvanam ahu" (They called him Indra Mitra, Varunam Agni and he is heavenly noble winged bird the sun; to what is one the Rishis gave various names. They called him Agni, Yama Matariswanam.)