Pre-twentieth century war was impossible without animals. Even today, many millions of animals are mutilated or killed each year in human warfare; some on the battlefield, some as “collateral damage”, but most in the development of weaponry. There is no technique of burning, poisoning, or mangling bodies which has not first been tried on animal flesh. In particular, in the Ancient Near East, horses meant only one thing, warfare. Nonconformists therefore found it notable that biblical texts forbade the king of Israel ownership of many horses, denying to ancient Israel the most effective weapon of their age, and the means of conducting aggressive warfare. It is, perhaps, no surprise that the early twentieth-century pacifist movement was dominated by people from a nonconformist background. This chapter explores the consequences of this for both the contemporary exploitation of animals in warfare, and for the conduct of war more generally, including the structural inter-connectedness of the “animal–industrial complex” and “the military–industrial complex”.