Learned scholars have divided Kṛṣṇa's age into three periods: the age up through five years is called kaumāra, the age from the sixth through the tenth year is called paugaṇḍa, and the age from the eleventh through fifteenth year is called kaiśora. While Kṛṣṇa is spending His days as a cowherd boy, He is in the kaumāra and paugaṇḍa ages. In the kaiśora age, when Kṛṣṇa appeared in Gokula, He acted as a cowherd boy, and then, when He was sixteen, He went to Mathurā to kill Kaṁsa.
The kaumāra age is just suitable for reciprocating the love of a child with mother Yaśodā. In the Tenth Canto, Thirteenth Chapter, verse 11, of Śrīmad-Bhāgavatam, Śukadeva Gosvāmī tells King Parīkṣit, "My dear King, although Lord Kṛṣṇa is the supreme enjoyer and the beneficiary of all kinds of sacrificial ceremonies, He still used to eat with His cowherd boyfriends. This is because at that time He accepted the pastimes of an ordinary boy, keeping His flute under His arm and His bugle on the right side in His belt, along with His cane. In His left hand He would hold a lump of rice paste with yogurt, and in His fingers would be pīlu, the king of fruits. When He would thus sit among His friends, it would appear that He was the whorl of a lotus flower and that the friends surrounding Him were petals. As they thus enjoyed joking among themselves, the denizens of heaven would become struck with wonder and would only stare at the scene."
Kṛṣṇa's paugaṇḍa age can be further divided into three periods—namely the beginning, middle and end. In the beginning of the paugaṇḍa age there is a very nice reddish luster on His lips, His abdomen is very thin, and on His neck are circles like those on a conchshell. Sometimes, some outside visitors would return to Vṛndāvana to see Kṛṣṇa and, upon seeing Him again, would exclaim, "My dear Mukunda, Your beauty is gradually increasing, just like the leaf on a banyan tree! My dear lotus-eyed one, Your neck is gradually manifesting circles like those of the conchshell. And in the shining moonlight Your teeth and cheeks are competing with the padmarāga jewels in their beautiful arrangement. I am sure that Your beautiful bodily development is now giving much pleasure to Your friends."