Mechanisms seem to be available at birth in the vertebrate brains to distinguish the domain of inanimate objects (for inferring physical causality) and the domain of animated objects (for inferring social causality). These include responses to biological motion, self-propelled motion and face-like stimuli in animals so different as newly-hatched domestic chicks and human newborns. Detecting the presence and understanding the intentions of other agents is crucial in order to survive and reproduce. Mechanisms to detect animacy (and agency) have been argued to underwent a sort of hypertrophic development in our species, likely because of the demands and the consequent complexities of our social life. There has been a long road from the primitive animacy detectors that we can see operating even in simple brains to the intricacies of agency attribution and theory of mind of human beings. Nonetheless, the origins of beliefs in supernatural things seem to be deeply rooted in the natural history of animacy detection.