To construct her fence, Karana uses the ribs of two whales that washed ashore years before. She plants them in the ground and ties them together with kelp. The house takes longer to build, partially because there are so few trees on the island that grow straight or tall enough to make poles. A legend among the people of Ghalas-at says that the island was covered with tall trees at the beginning of the world, when the gods Tumaiyowt and Mukat ruled. "Tumaiyowit wished people to die. Mukat did not. Tumaiyowit angrily went down, down to anther world, taking his belongings with him, so people die because he did." After searching for a long time, Karana finds enough poles to build her house. Her house has four poles one each side, one wall of rock, and a roof of eight poles bound together with sinew and covered with female kelp. Karana feels secure in her new house. Although animals come at night, they cannot get through the fence. Once her house is finished, Karana fashions some utensils from rocks. She makes a basket from reeds and seals it with pitch so that it can hold water. She also widens some cracks in her rock wall to make shelves that will keep her food safe from gray mice.
Since her basic needs are met, Karana turns her attention to the wild dogs. She knows she has to kill them or else they will kill her, just as they killed Ramo. She makes a heavier bow and better arrows, but runs into trouble making a spear. To finish her spear, Karana needs the tusk of a sea elephant, but does not know if she will be able to kill one; the task once took many men of her village to complete. Sea elephant tusks make the best spearheads on the island, however, and she is determined to get one.
Karana spends the night thinking about the law of her people that says women should not make weapons, but in the morning she heads for the beach. She spends a few minutes looking at the sea elephants, then chooses her target: the smallest of the six males on the beach, a relatively young bull who Karana can tell does not have a family. She sneaks up behind the bull and readies her bow, but the sea elephant gets up and heads toward on of the cows belonging to another bull. Karana takes her shot, and although the arrow flies straight, it misses because the bull has changed direction. The young bull Karana targeted is tackled from the side by the bull hose cow he had threatened, and a fierce battle ensues. As the two sea elephants fight on the shore, Karana, attempting to move out of their way, injures her leg. The two bulls fight all day and into the night. As the sun sets, Karana's leg begins to hurt even more and she goes home.
The creation of a permanent residence marks Karana's acceptance of the fact that she will likely be on Ghalas-at for some time. Only a few chapters earlier, this thought was too much to bear because of the loneliness it caused. Now, Karana is able to work steadily towards her goal. Karana is no longer so lonely on her island because she has a friend in her familiar surrounding. Another reason she no longer feels lonely is that she feels that the island of the blue dolphins is her home. In this section, Karana consciously works to make the island her home. The idea of "home" changes for Karana from a abstract concept to a concrete realization in this section, and though Karana remembers her tribe as she goes about making a home, he does not mention once the pangs of loneliness that had consumed her only a few chapters earlier.
Karana gives us an interesting glimpse into the lore of her people in this section. She says that her island was once covered with straight trees, but this was at the beginning of the world. What follows is a brief explanation of two of her people's gods: Tumaiyowit and Mukat. Tumaiyowit seems like a demonic figure, because he "[wants] people to die" and lives in an underworld. According to Karana, people die because Tumaiyowit went down into a world beneath the earth. This story has very little to do with twisted trees, and so there are several reasons that Karana may have introduced it. It could be intended by the author to enrich our understanding of Karana's people and their history. It is also possible that Karana enjoys thinking about the story because it reminds her of her people. Finally, it is possible that the question of death is on Karana's mind, and she brings up this story to remind herself why people have to die. Karana makes a new set of weapons in this section, and the traditions of her tribe that forbid women to make weapons comes up again. Karana is hesitant about making her new spear, but does so anyway. Chapter thirteen both questions and supports the superstitions surrounding the making of weapons by women. Such superstitions are invalidated because, as Karana makes it point to mention, her weapons work; her arrows fly straight. However, the superstitions are validated in that one of them actually come true. The night before she goes after the sea elephants, Karana wonders if she will be injured and have to face the wild dogs with her injury, and this is exactly what happens. However, Karana does not seem to notice this coincidence, and so it does not affect her.