Dog Behavior Question – Dog on Dog Aggression- My Dog has Become Very Aggressive in the Last 2 months

Dog Behavior Question – Dog on Dog Aggression- My Dog has Become Very Aggressive in the Last 2 months


I have a dog behavior question – my dog is showing dog on dog aggression and has become aggressive to people too – this is all very sudden. My dog is not quite 3 years old, neutered male he is a pit bull. I got him when he was 6-9 months but I not sure his age exactly. He was the nicest sweetest dog to humans and to dogs. I took him to the dog park at least 5 times a week and he played for hours. He loved people even more then the dogs, he would let anyone and everyone pet him. He has always been uncomfortable with much larger dogs, and he would growl and show signs he might do more when there were right up on him or if they tried to hump him, but i would take him away and all would be fine.

But about 2 months he started getting aggressive for no noticeable reason, the first time he snapped at a male Pit Bull dog that was not neutered, at a dog park he was with one of his favorite dogs so I thought he was being over protective of that dog, but then the next few times I took him to dog parks he would get mean to random dogs really quickly for no reason. Now he is barking and jumping at people like he wants to attack when taking a walk. He freaks out when people come near the car when he is with me. When I was taking him for a walk a few days ago, some people came up to pet him and he was wagging his tail and being happy for the attention and out of nowhere he got aggressive, and tried to bite.
What do I do? Could it be a medical issue? If so what could cause this? I’m so worried about him… I have to get this under control.

Thanks for reading

Hi, I am so sorry that you are having so many new problems with your dog. It is always a good idea to rule out any medical problems as sudden behavior changes can very often be traced back to an illness. I would get your dog checked out with your Vet as soon as you can to rule out any medical issues.

Sudden aggressive behavior can be due to a medical problem and/or a behavioral problem – and sometimes a culmination of the two. Although I am not a trained vet I will provide some general advice (this is advice only).

Medical Problems that Can Cause Aggressive Behavior

Hypothyroidism – This condition can cause a variety of symptoms including weight gain, loss of hair, lethargy and sudden aggressive behavior.

Neurological Problems – This can cause a variety of problems including aggressive behavior – causes can include Epilepsy, Brain Tumors – Hydrocephalus is one of the most common causes of sudden and unexpected aggression – this when fluid builds up within the brain.

Canine Seizures – This condition can involve aggressive behavior, salivation, your dogs posture may become aggressive, dilated pupils and sudden hostile behavior.

Arthritis – This condition is a very common cause of aggression in older dogs (or dogs that have developed the condition).

Canine Lyme Disease – This another cause of dog on dog aggression and with people.

I would take your dog to dog training classes as this is one of those problems that would really benefit from one on one tuition. By taking your dog to training classes you can ask other owners questions but also mix and socialize your dog with other dogs – and guess what the trainer will be able to correct any negative behavior at the very point that it is displayed. This is very important – hope this helps. I have also provided some links below.

Dog Obedience Training Online Guide

Dog on Dog Aggression and other Behavioral Problems

Thyroid Problems in Dogs

Canine Seizures

Canine Rheumatoid Arthritis

Canine Lyme Disease

Canine Neurological Problems