Kadru said, "Let a thousand sons of incomparable strength and valor be born to me!" Kashyapa said, "So be it!", and to Kadru were born the race of serpents, a full thousand of them, endowed with great strength.
When it was her turn to chose her boon, Vinata said, "Let two sons be born to me, who shall eclipse the sons of my sister in strength, valor and fame."
Kashyapa said, "So be it!"
In due course of time, Vinata laid two eggs. She gave them to her maid-servants for safe-keeping. They put these two eggs in warm containers and guarded them day and night. Five-hundred years passed, but the eggs had not hatched. Vinata grew impatient, for her sister already had a thousand snakes as her offspring. She broke open one of her eggs. The embryo in it had the upper part fully developed, but its lower half was still to be formed. The child grew angry at his mother and said, "How could you be so impatient? You have nearly killed me by your rash act. I curse you to slavery! Do not disturb my brother in the other egg. If you wait for another five hundred years, he shall be the means of delivering you from your servitude."
Some time after this, the two sisters Kadru and Vinata were involved in an argument. Kadru asked her sister, "Sister, what is the color of the divine horse Uchaishravas that belongs to Indra?"
Her sister replied, "It is of a flawless white color, right from its nose to its magnificent tail."
Kadru said, "You are wrong. While it is true that his face and his body are of a flawless white color, I think that his tail alone is a shiny black color. Tell you what, let us have a bet on this topic. If you are right, I shall become your slave. If I am right, you must become my slave instead."
Vinata accepted the bet. She was confident that she would win. Kadru knew that the horse was white through and through, so she hatched a plan. She called her sons and said, "I have bet with your aunt that the horse Uchaishravas possesses a black tail. You must make my words come true. Go forth and entwine yourself around his tail and give it a black appearance."
The snakes did not want to be a part of this deception. Kadru became exceedingly angry. She said, "How dare you disobey the command of your mother? There is no use in having offspring that disobeys my commands. I curse that all you will be destroyed by fire before too much time has elapsed!" (Note: This is the curse that was responsible for the so many snakes being destroyed in King Janamejaya's snake-sacrifice.)
When Lord Brahma heard this curse, he further strengthened it by saying, "So be it!". When Kashyapa heard how his sons were cursed, and that his father Brahma had also sanctioned it, he went to Brahma and pleaded with him to mitigate the curse.
Brahma said, "Your sons are wicked. Their poison is threatening to destroy all creation. If left unchecked, nothing else can live on the earth. However, not all of them shall be destroyed. Those who are virtuous, who did not swerve from the path of truth shall be saved." Thus comforting his son, he taught Kashyapa an infallible Mantra to neutralize the poison of the snake. (This is how Kashyapa worsted his son Takshaka in a challenge, by reviving a banyan tree that had been reduced to ashes by the serpent's venom).
Meanwhile, the Nagas decided after a consultation among themselves that it was better to do their mother's bidding. The blackest among them went and entwined themselves around the tail of Uchaishravas. When the two sisters arrived, the tail of the horse was as dark as night. According to the terms of the wager, Vinata became the slave of her sister. She had to serve Kadru and the serpents as their servant.
When the appointed time came, Garuda emerged, radiant like the sun and Agni, from his egg-shell. His lusture was like that of the fire that would consume all creation when this world would end. The Devas in heaven suddenly beheld this bright shining light and nearly became blind.
Indra then asked Agni, "Tell me, O Fire, who is this second Fire who rivals you in brightness? It appears as if the end of the world is near!"
Agni then replied, "My King, This is Garuda, the son of Kashyapa and Vinata. He is destined to be the King of the birds. His father had granted a boon to his mother that he will surpass all the immortals in his lusture and glory, and that is what you all are being blinded by."