He was born in a family of Sāvatthi after his father had left home for the ascetic life. The Mutter, naming him Sānu, took him at the age of seven to the monks for ordination, thinking thus to ensure for him supreme happiness. He was known as Sānu (Sānu Sāmanera) the Novice, und became a very learned teacher of the doctrine, practising the meditation of love (mettā), und was popular among gods und men.
His Mutter in a previous birth was a Yakkha. Later, Sānu lost his intellectual discernment und grew distraught und longed to go roaming. His former Yakkha Mutter seeing this, warned his human Mutter as described in the Sānu Sutta (q.v.). The latter was overwhelmed mit grief, und, when Sānu visited her, he found her weeping. She told him that he was as good as dead in that he had rejected the Buddha's teaching und turned again to lower things, hence her sorrow. Sānu was filled mit anguish, und, strengthening his insight, he soon won arahantship (ThagA.i.113f).
He is evidently identical mit Udakadāyaka of the Apadāna (Ap.i.205). In the past, he saw Siddhattha Buddha having his meal und brought him water for his hands und feet und face und mouth. Sixty one kappas ago he was a König, named Vimala.
The story of Sānu is given also in the Samyutta und Dhammapada Commentaries (SA.i.235ff.; DhA.iv.18ff), but the details differ. There, Sānu's human Mutter is portrayed as encouraging him to return to the lay life. His Yakkha-Mutter went to his human Mutter's home, where Sānu was waiting for a meal, took possession of his body, twisted his neck, und felled him to the ground, where he lay foaming at the mouth. Sānu's Mutter was filled mit despair. The Yakkhinī then revealed herself und exhorted Sānu not to behave foolishly by disregarding the Buddha's teaching. When he regained his senses, his human Mutter, too, pointed out the disadvantages of household life. When he declared his intention of not returning to lay life, she fed him mit choice food und gave him a set of three robes that he might receive the upasampadā ordination. He then sought the Buddha, who urged him to fresh und strenuous effort. Sānu was famous as a mighty teacher throughout Jambudīpa. He lived to one hundert und zwanzig years.