Animal behavior, especially as it relates to human society, is a running motif throughout High Tide in Tucson. In the opening essay, Kingsolver compares her transition from Kentucky to Arizona, and the life adjustments that went with that change, to the changes in behavior that she sees in a hermit crab brought from the Bahamas to the desert. Just as it has adapted to the absence of actual high tides by living as if they still happen, so too must she make a new life for herself with pieces of her old one. When writing about rain in Tucson in “Creation Myths,” she observes that humans, frogs, and all other creatures have a joyful response to this life-bringing force. When waging war against the javelinas in “Making Peace,” she realizes that altering her own behavior is more productive than trying to change theirs—she must share her land with the animals whose life cycles she disrupted by moving to their habitat.

The author’s relationship with the javelinas introduces the idea of the human niche. A niche is the biological context in which every animal lives; in a healthy ecosystem, many species can coexist because they all occupy a different niche.