The answer to this question can be found within the second part of Julie of the Wolves. When Julie/Miyax is four years old, Kapugen's wife dies. Kapugen is absolutely overwhelmed with grief. His grief is so extensive that he leaves his job in Mekoryuk and all of his material possessions to take his daughter and live in a seal camp outside the town. Kapugen is able to move on from the grief caused by the loss of his wife by immersing both himself and his daughter in the "old ways" of the Eskimo. Instead of a modern house in town, the two now reside in a "little house of driftwood, not far from the beach." Even though Julie has lost her mother, she is happy with her "infinitely good" life as a true Eskimo.
Unfortunately, Kapugen's family does not agree with his reaction or his decision. We can see this in the actions of Julie's Aunt Martha, who appears at the seal camp one day in order to yell at Kapugen for not sending Julie to school and to chide him for taking her away from modern conveniences. Unfortunately, Aunt Martha's severity convinces Kapugen to allow Julie to live with her. Julie's frustration continues. First, she agrees to an arranged marriage in order to flee Aunt Martha. Next, she escapes the arranged marriage in order to avoid rape. This is how Julie ends up on the Alaskan tundra.