The story of the origin of Uchchaihshravas is found in the Bhagavad Purana. This divine horse appeared during the churning of ocean (Samudra Manthan) by Devas (demi gods) and Asuras (demons). Uchchaihshravas means one with long ears or one that neighs loudly.
Uchchaihshravas is white like the moon and has seven heads. This flying horse was taken by Indra, the king of Devas. It is also the king of the horses.
The color of the tail of Uchchaihshravas was the reason for Vinata and Garuda becoming the slave of Kadru and her serpent sons. Vinata was sure that the tail of Uchchaihshravas was white but Kadru said it was black. After a bitter argument it was decided that whoever was wrong would become the slave of the winner.
Kadru’s serpent sons hanged to the tail of Uchchaihshravas and made it appear black, when in reality the tail was white. Thus Vinata and her son Garuda became the slaves of Kadru and her sons.
Another story has it that Goddess Lakshmi once happened to see Uchchaihshravas. She was lost in admiration and did not pay attention to Vishnu. For this she was cursed to be born as mare in the Hehaya dynasty.