With the intention of analysing changes in natural history, human variation and the exercise of imperial power across the British Caribbean, this study poses the following questions: How did changes in natural history impact the understandings and applications of human variety, 1700–1750? How did natural history influence the exercise of imperial power in the British Caribbean? The study posits that there is a connection between natural history and imperial power. Through the contexts of the history of natural history and the history of fear, biopolitics acts as a theoretical framework wherethrough two themes of natural history, "spirits" and weaponry, are analysed using the travel writings of Hans Sloane, Henry Barham, Charles Leslie, Griffith Hughes and Patrick Browne. The study finds that natural history mainly manifested itself as a tool of imperial power by manufacturing two primary ways in which humans could, on demand, be excluded from the realm of humanhood. The first consists of an early eighteenth-century "moral conditional humanhood", manifesting as a symptom of natural history’s theological focus. The second is a mid-eighteenth-century "biological conditional humanhood", being a symptom of that time’s natural-historical focus on biology to determine human variation. The study finds support for a connection between natural history and the exercise of imperial power, for instance, concerning how fear is emphasised in the early eighteenth-century – to hide the violence exercised by Europeans – to then become hidden in the mid-eighteenth-century. In addition, human variation presented itself with a malleability, with the enslaved population being more malleable than the native population.