Dogs are capable of jealousy much like that seen in young children.
Science has established that dogs experience the same basic emotions as does a 2- to 3-year-old child. That means to say that a dog can feel happy, sad, angry, fearful, disgusted, and surprised. The question of whether they feel the more complex social emotions, including guilt, pride, shame, envy, and jealousy is still open to investigation. Jealousy, for example, is an emotion that involves three individuals. It is the unhappy feeling of being replaced in someone else’s affections or the suspicion that the object of your affection has been unfaithful in your relationship.
Some researchers feel that this involves some pretty complex reasoning processes, which perhaps only humans are capable of. However, in a new report, a team of researchers from the School of Psychology at the University of Auckland in New Zealand suggests that dogs are capable of this emotion. “Research has supported what many dog owners firmly believe, dogs exhibit jealous behavior when their human companions interact with the potential rival,” said Amelia Bastos, the lead author on this paper.