While the nonhuman has generally been disregarded as irrelevant to Mexicanist and Central Americanist scholarship on race, sexuality, gender, and politics, this project argues that thinking through the animal was a key method through which twentieth-century writers revised what ought to be considered “natural” and normative. The hypothesis that this project explores is that the animal operates as a figure that contests how the human—or a certain type of human marked by sexuality, gender, and race—has been produced and privileged by society. I argue that the turn to species intensifies during moments of ideological change. Species Sadness thus provides a framework for thinking about three periods of political turmoil in Central America and Mexico in relation to each other—rising fascism in the thirties, incipient feminism in the sixties, and the Sandinista revolution of the seventies—and argues that during moments of ideological revision, the concept of species is central. Interspecies erotics, domestic intimacy with pets, and animal vulnerability, are all unusual, yet key narrative tools to push readers to think beyond the human and define an ethics that is attentive to alterity.