You’ve known it all along, but a recent study published on PLOS.org shows that dogs do get jealous.
Researchers Christine R. Harris and Caroline Prouvost determined that dogs do indeed get jealous when their people showered affection on a decoy toy.
The current experiment adapted a paradigm from human infant studies to examine jealousy in domestic dogs. We found that dogs exhibited significantly more jealous behaviors (e.g., snapping, getting between the owner and object, pushing/touching the object/owner) when their owners displayed affectionate behaviors towards what appeared to be another dog as compared to nonsocial objects. These results lend support to the hypothesis that jealousy has some “primordial” form that exists in human infants and in at least one other social species besides humans."
The dogs tried to get between their owners and the toy, and some dogs even snapped at the dummy dog. We can interpret this as jealousy, or as as resource guarding, which is commonly used term in training and behavior medicine.
For the full article, click here to read this fascinating article about animal behavior, cognition and aggression.