Why do Some Dogs Have Aggression?

Dog aggression can stem from a variety of factors, often involving a combination of genetics, environment, socialization, and past experiences. Here are some reasons why some dogs may develop aggression towards other dogs:


Certain breeds are more prone to displaying aggressive behaviors due to their genetic predisposition. Breeds historically bred for guarding or protection might be more likely to show aggression. It is always important to research breed characteristics before adding a new dog to your family.

Lack of Socialization

Dogs that haven’t been exposed to a variety of other dogs, people, or environments during their critical socialization period (usually up to 16 weeks of age) might develop fear or aggression towards unfamiliar dogs, people, and things.

Negative Experiences

Past negative encounters or traumatic experiences can lead to defensive or aggressive behavior as a way to protect themselves. It is important if your puppy or dog does have a negative experience in the world to try to aim for neutrality as soon as possible after said event.

Resource Guarding

Dogs may show aggression towards other dogs when they perceive a valuable resource (food, toys, territory) is being threatened. While you cannot necessary remove all resource guarding tendencies from a dog through training, there are definite ways to safely manage most aspects of the behavior.


Fear can trigger aggressive responses when a dog feels threatened or believes they have no other means of escape. It is important to have clear boundaries for dogs like this, so their fear does not control their every move.

Protective Instincts

Some dogs are naturally protective of their owners or their home, leading to aggression towards perceived threats. Training is paramount for these dogs. Many Beyond The Leash clients have previously had issues with their dogs guarding them, and teaching reliable loose leash walking skills has been the key to their future success.

Reactive Dog

Territorial Behavior

Dogs may display aggression as a way to establish dominance or protect their territory. If you have a dog like this, it is highly recommended to not leave them unsupervised in your yard. When they start rehearsing such behavior, you can simply call them back to the house. This technique prevents a potential bite, nip, or scratch to an unexpected service or delivery person.

Reactive puppy

Medical Conditions

Pain or discomfort due to medical conditions can lead to irritability and aggression. The first value many veterinarians will check when aggression issues arise is thyroid.

Hormonal Influence

Intact (unspayed/unneutered) dogs, especially males, might display aggression due to hormonal influences, especially around other dogs of the same sex. Spaying and neutering does not always solve this issue, but hormones can contribute to the initial onset of the aggressive behavior.

Poor Training or Handling

Inconsistent or inappropriate training methods can lead to confusion and anxiety in dogs, potentially resulting in aggressive behavior. If you are always choking up on the leash when you see a potential threat, you may be encouraging aggressive behavior. You may also see aggressive tendencies arise if you are trying to assert dominance over a dog. When dogs feel cornered or challenged, they may feel triggered to react aggressively.

Consult A Professional

It’s important to remember that each dog is an individual, and the reasons for their aggression can vary widely. If you’re dealing with a dog displaying aggressive behavior, consulting with a professional dog trainer is recommended to assess the specific triggers and develop a tailored training and behavior modification plan. At Beyond The Leash we specialize in aggression, so if you have been feeling hopeless about your dog’s behavior, set up a Solutions Session today to see if we can help!