Science on the Range uses bats and their scientists to provide a historical and ecological account of both the range and Texas’ sovereignty as a settler colonial state. The range is a logic invested in who gets to live where and animated by the contradictory desires for freedom and enclosure. Its history is traced through stories both mythic and scientific. In studying how bat scientists study bats across flat plains and inside caves – and in a state that is 97% private property – I offer a series of case studies that illustrate the inevitable intersections of human life and wildlife, even as historical, legal, and epistemological regimes try to keep them apart. Through looking at the formation of the Texas Rangers as a vigilante police force, rangeland management as a type of land-use, the ecological study of animal ranges, the politics of a prison occupied by bats, and the mathematics of a range altogether, I claim that, despite its popular representation, science, the environment, and politics are bound together in Texas through the range, the worldmaking project of settler colonialism, and its function as a kind of laboratory for new figurations of nature and politics, namely around nativism, separatism, and white supremacy. In all of this, Mexican free-tailed bats remain the dissertation’s model organism: as border-crossers, disease vectors, economic aids, and environmental disruptors, they interrupt storytelling conventions and inherited scripts of environmental politics and direct my ethnographic attention.