Is your dog showing aggressive behavior such as:

• Barking, lunging, or snarling at other dogs or at people when out on leash
• Getting into fights with other dogs, including other dogs in the household
• Growling at, snapping at, nipping, or biting people
• Chasing and possibly injuring smaller animals like cats or small dogs
• Guarding possessions like his food bowl, toys, chews, or even his place on your couch

Aggressive Behavior in Dogs
Canine Rivalry