Aggression in dogs can be genetic or stem from a bad experience in the past. The term also has a wide meaning, from just growling at other dogs occasionally on a walk to biting and snapping at you. Because aggression can lead to biting, work with a professional trainer before attempting to fix the problem yourself.
You are the pack leader and your dog will mimic your behavior. If you’re on edge all the time, your dog will be too. His behavior is often just a reflection of yours. The next time he gets worked up, step back and look at your actions. By tensing up and yelling frequently, your dog could start to act the same way, growling and barking at other people or dogs. Be firm with your pup, while remaining calm and collected when giving orders. Over time, he’ll start to pick up on your softened persona and start acting that same way himself.
Expose Him to Everything
It’s possible that your canine’s previous owners didn’t take him out of the house much and he didn’t get enough exposure to anything in the world. Or if he’s still young, his aggression could stem also stem from minimal exposure to life experiences. Show him the ropes, but take baby steps. Put him on a leash and start with your own yard. Walk him around the perimeter, talking to him and tossing him treats along the way. He’ll start getting used to fluttering birds and barking dogs. When he gets familiarized with this comfort zone, take him on short walks around the block, being careful to avoid other dogs or humans at first. As he continues to progress without any angry outbursts, lengthen your walks and take him to different areas to expose him to different surroundings.
Start socializing your pup with people, since strangers coming onto the property can set off aggressive eruptions in some dogs. Have the mailman slip treats through the slot when the mail comes or ask your neighbor to come over a few times each day and bring goodies. Your four-legged buddy will quickly figure out that having humans on his property isn’t so bad. Then you can have your neighbor come to the door with her dog. Open up the main door, leaving the screen door shut, and let them sniff one another -- both dogs should be on a leash. You can do the same thing with a baby gate if you don’t have a screen door. Offer your pooch treats and praise him for good behavior. Gradually work up to taking him on a leash to the dog park or pet store, staring out by walking the perimeter.
Get Him Fixed
If your pooch hasn’t been spayed or neutered yet, that surgery might be something to consider. Dogs who are still intact have raging hormones and sex drives that can make them overly protective and aggressive at times. This is why an unneutered male lifts his leg and sprays or picks a fight with a dog that comes into his yard. He’s alerting all other dogs that this is his turf. Those hormones mellow out after sterilization though, helping to minimize aggressive outbreaks.