The classical view that equates rationality with adherence to the laws of probability theory and logic has driven much research on inference. Recently, an increasing number of researchers have begun to espouse a view of rationality that takes account of organisms ’ adaptive goals, natural environments, and cognitive constraints. We argue that inference is carried out using boundedly rational heuristics, that is, heuristics that allow organisms to reach their goals under conditions of limited time, information, and computational capacity. These heuristics are ecologically rational in that they exploit aspects of both the physical and social environment in order to make adaptive inferences. We review recent work exploring this multifaceted conception of rationality. Humans and animals alike make inductive inferences. Firefighters predict how fires will progress from cues such as smoke and roof ‘sponginess ’ 1, while peahens use the elaborateness of peacocks ’ tails to infer their fitness before deciding whether to mate with them 2. The cues on which organisms base their inductive inferences are typically uncertain: