Here, we can see an adult Golden Retriever setting a boundary with a puppy, something most humans forget to do during puppyhood. To be clear, the adult Golden Retriever is not being aggressive in this moment. She is claiming the bone by communicating to the puppy with a warning (direct eye contact & teeth showing). The puppy feels the calm confident energy and moves away. The adult Golden Retriever immediately stops warning and goes back to chewing the bone to show the puppy that's what she want