Dogs’ excellent sense of smell is well-known, whether it is in the context of searching for people or for contraband substances. However, the question of how dogs understand what they perceive with their sense of smell has largely been unexplored. In a study published today in the Journal of Comparative Psychology, scientists at the Max Planck Institute for the Science of Human History and the Department for General Psychology and Cognitive Neuroscience (Institute of Psychology) at Friedrich Schiller University of Jena, investigated this question and found evidence that dogs create a “mental representation” of the target when they track a scent trail. In other words, they have an expectation of what they will find at the end of a trail.