Play Aggression is defined as barking, growling or snapping while playing. However, a play growl is different from a serious one and normal dogs immediately know the difference. True aggressive growls are lower pitched and prolonged. A play growl is usually high-pitches, short, and repeated frequently. Changes in the pitch may happen too quickly to safely detect.
Puppies that have not been exposed to other dogs often to other dogs may play inappropriately, or may play inappropriately because the owner encouraged rough play. Some play aggression is the result of abandonment, lack of interaction (in a shelter for example), or restricted access to other dogs in a normal play situation.
**Aggression categories compiled from:
Clinical Behavioral Medicine for Small Animals, Karen L. Overall, M.A., V.M.D., Ph.D. Diplomate, American College of Veterinary Behavior, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia. Pennsylvania, Mosby, Inc. 1997
The Dog Who Loved Too Much: Tales, Treatments, and the Psychology of Dogs, Dr. Nicolas Dodman, BVMS, MRCVS, Bantom Books, 1997