Reasons for aggressive behavior in dogs
The need to establish supremacy is one of the reasons for a dog's aggression. Dogs are pack animals with a strict hierarchy and it is their nature to seek dominance in a certain pack. Dogs normally assume that people are part of their pack so they take the alpha dog post.
Besides dominance as one of the reasons for aggression in dogs, your pet's territorial nature is also common. Dogs often define their home and family as ownership, and they will protect them all intensely. Violent behavior may occur when your dog feels that someone has trespassed on their space or is threatening its family. While it is understandable for this kind of aggression in dogs, it is still not acceptable amongst humans.
Aggression due to fear is another defensive reaction from dogs who feel that they are in danger of being harmed. A frightened dog will fight and strike back because he wants to protect himself from the incoming threat or danger. Fear should not be neglected as this may be one of the probable causes of dog aggression that is usually mistaken for direct aggressiveness. It is usually characterized by growling, with the dog's ears pulled back and its tail between its legs.
Most animals are predatory in nature including dogs. While other dogs are afraid, most dogs love to hunt, chase and prey on smaller dogs, animals and even kids.
One more reason for aggression amongst dogs is redirected aggression, and is sometimes misunderstood. This kind of behavior can be seen when a dog lets out his aggression on the actual object causing the fear, anger or territorial thoughts. A good example, if your dogs are in the yard and an individual they thought as a trespasser enters the house, the dogs may turn on one another. But, some individuals do not understand the unexplainable aggression, just because they don't understand where the aggression originated.
Medical Reasons for Aggression
Lastly, there might be medical reasons for aggressive behavior in dogs that have been diagnosed. Although most dogs can be trained to not be aggressive if its something behavioral, on few occasions, there is an underlying medical condition that needs to be treated. Moreover, some females are very violent when they are pregnant or nursing, same as maternal protectiveness is very common in many nursing females, and aggressive behavior can be restrained through good training as early as they are still a puppy.
Remembering the reasons for aggression in dogs and observing where your dogs fits can be the initial step in curbing the behavior. There are few varying training methods you can use to limit the different types of aggression, so knowing the reasons behind your pet's aggressive tendencies can help you determine what training methods to use to be more effective.