Background information:
Dogs jump and mouth for a variety of reasons. The first is play. Dogs play with each other by jumping and mouthing, so it comes naturally to play with people in the same way. The second is greeting behavior. Jumpy/mouthy dogs love people and exuberantly greet most new people that they meet, with jumpy and/or mouthy behavior. Jumpy/mouthy dogs often show this behavior when a person reaches out to pet them. The third is to get a person’s attention. There is no better way to get a response, either positive or negative, than by jumping up. Young dogs develop social and emotional attachments to other dogs and people through play. When playing with their littermates, puppies learn to control the pressure of their bites. If one puppy bites another too hard, the puppy who was bitten often reprimands the biting puppy, and either the conflict is resolved or a fight may break out. Puppyhood is also a perfect time for people to begin teaching puppies how to play. Often by the time a puppy is 4 months old, play mouthing decreases. However, if people are not around to provide consistent training and companionship, or less commonly, if people are around, but aren’t able to provide enough exercise, enrichment and training to meet a high energy dog’s needs, the mouthing may not decline.
Influence of stress: The stress of being in a shelter, especially related to decreased interaction with people, decreased exercise, and lack of control of their environment, often results in increased attention seeking (jumping, mouthing, barking) behaviors. Some jumpy/mouthy dogs initially respond to a behavior plan, but their jumpy/mouthy behavior worsens as they stay in a shelter for long periods of time.