Aggressive behaviour in a dog refers to any behaviour connected with becoming still and rigid, growling, snarling, baring teeth, lunging, and nipping or biting. The purpose and motivation behind these behaviours are to increase distance.
You cannot design a plan to modify your dog’s behaviour until you understand its motivation. The most common types of dog aggression include:
1) Fear Aggression
The dog takes an offensive posture to increase the distance from the trigger (e.g., human or dog). In short, the dog takes an attack-is-the-best-defence approach.
This aggression can also be directed at inanimate objects (e.g., vacuum cleaners, skateboards, scooters, bicycles and cars in motion.
Fear aggression can simultaneously present with avoidance behaviours (i.e., the dog tries to escape from the trigger) and aggressive behaviours.
2) Territorial Aggression
Aggression is directed toward humans or other dogs in the dog’s perceived “territory”.
Dogs presenting with this type of aggression can sometimes show few signs of aggression outside of their “territory”.
The intensity of the aggression can be significant.
The dog’s “territory” is typically the inside of their home but frequently extends to the area surrounding their home.
3) Idiopathic Aggression
An unpredictable type of aggression because the triggers are not known or understood. The word “idiopathic” means “relating to or denoting any disease or condition that arises spontaneously or for unknown cause”.
This type of aggression can be very dangerous, including sudden and severe outbursts with little to no warning. Owners describe seeing their dog’s eyes as being glazed.
It often has a neurological origin.
4) Prey Aggression
The behaviours associated with this type of aggression are associated with the pursuit of prey animals.
Prey aggression toward humans is extremely rare.
5) Resource Guarding Aggression
Dogs use aggressive behaviours to keep other dogs and humans away from their food, treats, toys, space, owners and other dogs.
It is arguable that the dog is fearful of losing a valued resource, thus making it fear-based.
This type of aggression is particularly susceptible to escalation and often has an underlying pain issue motivating it.
6) Redirected Aggression
The dog might become aggressive toward a person who attempts to break up a dog fight.
It may also happen when the dog cannot reach the trigger, like another dog across the street.