Illustrating a new methodology identified as animality studies, The Birth of a Jungle explores animality at the turn of the twentieth century in the U.S.-a moment when shifts in what it meant to be both human and animal produced new ways of thinking about various human behaviors, including homosexuality, labor exploitation, and the lynching of black men. Throughout the study, Michael Lundblad explores what he identifies as the discourse of the jungle: Darwinist-Freudian constructions of human behavior that could be explained by animal instincts that were supposedly naturally violent in the name of survival and heterosexual in the name of reproduction. These new formulations were often contested rather than reinforced, however, in Progressive-Era literary and cultural texts. The Birth of a Jungle ultimately reveals the significance of animality in relation to the history of sexuality, literary naturalism, and critical race studies, while highlighting how the discourse of the jungle remains a disturbing yet powerful presence today.