Emotions play an essential role in animal welfare. Yet when one attributes emotions to an animal he/she is often accused to be anthropomorphic. We proposed to use theories from cognitive psychology whereby the emotion results from the evaluation of a triggering situation according to elementary characteristics (its suddenness, unfamiliarity, pleasantness, predictability, controllability…). For instance, fear is experienced in front of a situation which is unfamiliar and unpleasant whereas anger is experienced when we can control such a situation. In humans emotions can be detected by facial expressions. We looked for possible equivalents in animals, here ear postures in sheep. We exposed sheep to situations of which we manipulated the elementary characteristics (suddenness, unfamiliarity, etc.). We found that sheep use similar checks as humans, with the elementary characteristics of situations modifying their gross behaviour and stress responses. We then identified four main ear postures: ears horizontal, ears pointed up, ears pointed back, and asymmetric posture. We observed that i) the horizontal posture corresponds to a neutral state, ii) sheep point their ears backward when they face unfamiliar, unpleasant, and uncontrollable situations – hence likely to induce fear -, iii) they point their ears up when facing a similar situation but controllable – hence likely to induce anger -, and iv) they use the asymmetric posture in very sudden situations – likely to induce surprise -. By merging psychology and animal behaviour, we are thus able to propose an interpretation of ear postures in sheep in relation to their emotional states.