The tale of Indra, King of Gods and Yuvanaswa, an ancient king, and his desire to bear a heir. Yuvanaswa accidentally drinking a potion intended for his wife, bears a child that he cannot feed. Indra slit his thumb, and because he was a god, his veins were filled with life-giving nectar. And so, he let the future king suck his thumb. And that is why babies, being born with the memory of their divine ancestors, still suck their thumbs.