All cosmopolitan approaches to global distributive justice are premised on the idea that humans are the primary units of moral concern. In this paper, I argue that neither relational nor non-relational cosmopolitans can unquestioningly assume the moral primacy of humans. Furthermore, I argue that, by their own lights, cosmopolitans must extend the scope of justice to most, if not all, nonhuman animals. To demonstrate that cosmopolitans cannot simply ‘add nonhuman animals and stir,’ I examine the cosmopolitan position developed by Martha Nussbaum in Frontiers of Justice. I argue that while Nussbaum explicitly includes nonhuman animals within the scope of justice, her account is marked by an unjustifiable anthropocentric bias. I ultimately conclude that we must radically reconceptualise the primary unit of cosmopolitan moral concern to encompass most, if not all, sentient animals.