ABSTRACTCuriosity is a core driver for life‐long learning, problem‐solving and decision‐making. In a broad sense, curiosity is defined as the intrinsically motivated acquisition of novel information. Despite a decades‐long history of curiosity research and the earliest human theories arising from studies of laboratory rodents, curiosity has mainly been considered in two camps: ‘linguistic human’ and ‘other’. This is despite psychology being heritable, and there are many continuities in cognitive capacities across the animal kingdom. Boundary‐pushing cross‐disciplinary debates on curiosity are lacking, and the relative exclusion of pre‐linguistic infants and non‐human animals has led to a scientific impasse which more broadly impedes the development of artificially intelligent systems modelled on curiosity in natural agents. In this review, we synthesize literature across multiple disciplines that have studied curiosity in non‐verbal systems. By highlighting how similar findings have been produced across the separate disciplines of animal behaviour, developmental psychology, neuroscience, and computational cognition, we discuss how this can be used to advance our understanding of curiosity. We propose, for the first time, how features of curiosity could be quantified and therefore studied more operationally across systems: across different species, developmental stages, and natural or artificial agents.