People like to distinguish between capacities that are ‘innate’, ‘in the genes’ or ‘biological’ and those that are ‘acquired’, ‘learned’ or ‘psychological’. These are, or at least build on, folk distinctions. We hypothesize that they represent characteristic processes of, respectively: intuitive biology, the evolved cognitive system for gathering knowledge about animals; and intuitive psychology, the evolved cognitive system for managing relationships with other people. This hypothesis predicts a privileged connection between appraising an agent as animal or animal-like, and judging its capacities to be innate. We present five pre-registered studies with 1008 UK adult volunteers, testing different aspects of this prediction. Participants judged the same capacity more innate if the actor was described as an animal (study 1), and judged an actor less human if its capacities were described as innate (study 2). The degree to which a capacity was considered innate in humans was very strongly predicted by the degree to which it was thought present in other animals (study 3). We also investigated differences in innateness judgement by autism spectrum diagnosis (studies 4 and 5) and sex. We discuss the implications of the findings. If the folk concept of innateness represents our default mode of making inferences about animals, then certain scientific claims, for example concerning flexibility and individuality in animals, or innate bases of cognition in humans, will jar with many people’s intuitions.