It is a common claim in debates about abortion and the killing of animals that individuals, such as foetuses and non-human animals, that have psychological capacities significantly lower than those of adult human persons also have a moral status lower than that of persons. And those who defend this claim typically assume that it implies that the moral constraint against killing a foetus or animal is, if other things are equal, weaker than the constraint against killing a person. Many of these same people also claim, however, that the difference in moral status makes no difference to the strength of the constraint against causing suffering. They argue that the reason not to cause suffering to an individual who neither deserves nor is liable to be caused to suffer is equally strong whatever the nature or moral status of the potential victim is. There is, however, a type of individual whose psychological capacities and moral status are such that it is plausible to believe that the reason not to cause them to suffer is weaker than the reason not to cause equivalent suffering to a person. Most non-human animals are psychologically intermediate between these low-status individuals and persons. This raises the question, which is explored in this chapter, whether most animals have an intermediate moral status that makes their suffering matter more than that of the low-status individuals but less than that of persons.