Coyotito
Coyotito, Kino and Juana's infant son, is the catalyst for his parents' obsession with the pearl. Both of his parents want the pearl to help pay for his recovery from the scorpion sting and for his education, so that he will not be limited by the same oppression under which his parents have suffered.
Doctor
The doctor is part of the system that oppresses Kino and his family. The villagers know "his cruelty, his avarice, his appetites," his laziness, and his incompetence. His sense of superiority prompts him to regard Kino and his neighbors as animals and so determines that he need not treat them. Only after he learns of Kino's pearl does he offer help so that he may be able to get his hands on it and regain the luxurious life he has enjoyed in Paris. To that end, he deceives Kino and Juana about Coyotito's illness and his own powers as a healer.
Juan Tomas
Kino's brother Juan Tomas provides Kino with shelter and wise counsel.
Juana
Juana is a dutiful wife who rises every morning to make breakfast for her family. She exhibits a fierce, instinctual need to protect her child as evidenced by her clearheaded response to the scorpion's sting and her insistence that they take him to the doctor, knowing that there is little chance that the doctor will see him yet ready to face the resulting shame. Coyotito is Juana's first baby and so he is "nearly everything there was in [her] world."
Her strength and endurance, however, are her most dominant qualities. Kino "wondered often at the iron in his patient, fragile wife" who "could arch her back in child pain with hardly a cry" and "stand fatigue and hunger almost better than Kino himself." He notes that "in the canoe she was like a strong man." Although patient with and obedient to her husband, she tries to convince him to throw away the pearl when she recognizes the danger it brings.
Her endurance is displayed after Kino beats her. As he stands over her with his teeth bared, she stares as him "with wide unfrightened eyes." She accepts that he had been driven over the edge of reason and decided "she would not resist or even protest." As a result, Kino's rage disappears and is replaced by disgust for what he has done to her.
Juana shows a great and patient understanding of her husband. After he beats her, she feels no anger toward him, recognizing that as a man "he was half insane and half god." She knows that he will "drive his strength against a mountain and plunge his strength against the sea" and that he would inevitably be destroyed by both. Although puzzled by the differences she recognizes between men and women, she "knew them and accepted them and needed them" because as an Indian woman "she could not live without a man." She then determines to follow him, hoping that her reason, caution, and "sense of preservation could cut through Kino's manness and save them all." Juana endures the pain of her injuries as she escapes with Kino and Coyotito.
Her ability to defy her husband by attempting to throw the pearl in the sea while admitting that she could not survive without him reveals her great courage. She is driven by her need to "rescue something of the old peace, of the time before the pearl." Yet after Kino kills his attacker, she shows her resilience when she immediately admits that the past was gone, "and there was no retrieving it. And knowing this, she abandoned the past instantly. There was nothing to do but to save themselves." The death of her child appears to break her, however. As she walks back to the village at the end of the story, "her wide eyes stared inward on herself" and she "was as remote and as removed as Heaven.
Kino
Even though he lives in poverty, Kino is content at the beginning of the story because he is surrounded by the family he loves. It is only after his child's life is threatened by the scorpion bite that Kino determines that he will rebel against the system that oppresses him.
He is connected to his ancestors through their songs, which he often hears in his head. The frequency of the Family Song and the Enemy Song suggests his strong link to those ancestors as well as to his environment. Kino experiences a combination of rage and fear as he confronts his oppressors, showing strength as well as an intuitive assessment of the reality of his position. He is a proud man who feels shame when he stirs up the courage to challenge that position and is rebuffed.
Like Juana, he is a responsible parent who strives to provide the best life possible for his child. This commitment gives him the courage to rebel against the status quo by calling on the doctor, by refusing to accept the offer from the pearl buyers, and by fleeing the village after he murders one of his attackers. His loyalty is also expressed toward his neighbors when it does not even occur to him to take one of their boats during his escape.
His obsession with the pearl is prompted by his desire for respect and power, but most importantly for the education of his child. He wants to be able to marry Juana, to buy a rifle that can "[break] down the barriers," to dress his family in nice clothes, and finally to enable his son to free himself and his people from subjugation.
Kino's fierce desire to provide for and protect his family reduces him to a primal state. Ironically that desire to provide for them causes him to viciously attack Juana. Later, after he kills his attacker, the narrator concludes that Kino is "an animal now, for hiding, for attacking, and he lived only to preserve himself and his family." This primal nature enables him to escape his trackers, at least initially. The narrator notes that "some ancient thing stirred in Kino. some animal thing was moving in him so that he was cautious and wary and dangerous." At the end of the story, he appears broken as he retains his primal state. He, along with Juana, appears "removed from human experience." He "carried fear with him" and "he was as dangerous as a rising storm."