Humans are able to interpret the behavior of others by attributing mental states to them (and to themselves). By adopting the perspectives of other persons, they can assume their emotions, needs and intentions and react accordingly. In the animal kingdom, the ability to attribute mental states (Theory of Mind) is a highly contentious issue. Cognitive biologists could demonstrate with a new test procedure that dogs are not only able to identify whether a human has an eye on a food source and, therefore, knows where the food has been hidden. They can also apply this knowledge in order to correctly interpret cues by humans and find food they cannot see themselves.