Once upon a time, among the Hamadryads in the sacred band of followers of goddess Artemis, was the daughter of Lycaon, known as Kallisto. The band of chaste Artemis comprised only of virgins and thus, laying her hand on the bow of Artemis, Kallisto had taken a vow of virginity. But Zeus burned for the love of Kallisto, and taking the disguise of Artemis, he secretly seduced her.
While hunting in the woods, Artemis and her band, came across a shadowy grove surrounded by thick oak trees, where in the middle was a fountain bursting with cool water. Artemis decided to halt and enjoy a bath in the refreshing water. All the nymphs started to put off their robes, but Kallisto appeared ashamed and bashfully delayed. When Kallisto did take off her tunic, her bloated belly was quite plainly visible. Self-convicted, Kallisto was proved to be a mother.
When Artemis questioned Kallisto the cause for the swollen belly, Kallisto replied it was Artemis herself who had seduced her. Artemis was furious and she expelled Kallisto from her chaste band. But Hera, the wife of Zeus, was angry at Kallisto and in jealous indignation, she changed Kallisto into a wild she-bear. The pregnant Kallisto, as a wild she-bear, roamed the mountains and in the animal form, bore a human son named Arcas. Zeus took the babe Arcas and gave him to the Pleiad Maia, Hermes’ mother, for upbringing.
Arcas grew up and while hunting in the forest, he came across a she-bear, who was his mother Kallisto. Overjoyed to see her son after so many years, Kallisto desired to speak to him, but only growls came out from her bear-mouth. Seeing the bear growling at him, Arcas aimed his sharp javelin and was about to kill his own mother, when Zeus intervened. Zeus transformed the she-bear into the constellation Ursa Major, and Arcas into the constellation Ursa Minor, thus allowing them both to have immortality.
Excerpt from the book “Once Upon A Time-II: 150 Greek Mythology Stories” by Rajen Jani