Aggression in
Dogs

The complicated subject of forms and causes of aggression targeted toward another dog basically falls under two headings; fear or dominance. Broadly speaking, dogs displaying aggression to either sex or breed generally are motivated by fear, dominance aggression tends to be between two dogs of the same sex stimulated by competition for resource or vying with an innate drive to be the boss. There are exceptions of course, and variations within both forms.​

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Dominance aggression. 

Dogs are pack animals. They do not expect equality, and have a natural genetic predisposition to find their place within the pecking order, or dominance hierarchy of that pack. Aggression is usually displayed (but not exclusively) by males aged between 2 – 2 and a half years and usually toward other members of the pack but again not exclusively. This may be provoked by disturbing from sleep or rest, being stared at or staring between subjects, guarding, blocking entrances and general priority access to resource. Dominance aggression may be described as the relationship of individuals through force and submission, priority access and consistent deference. Dominant postures include standing over an object and general guarding, direct eye contact, a rigid stiff posture and bearing of teeth. Dominance may be genetically inherited physically during early masculinisation of the brain and overall size, and learned through success of battle during stages of life. Indeed, the dominant dog enjoys the cavalier flair and will be a likely bully around the park. He may have received a lack of canine discipline as a puppy and allowed to dominate other pups. 

 

Possessive, competitive aggression and sibling rivalry. 

A form of dominance aggression which is likely to be exasperated by human intervention. Two dogs of similar size, age, and the same sex are unable or not permitted to determine dominance and submission. Triggered by competition for resource such as toys, food, space and attention. The unwitting owner may aggravate the situation by perhaps giving attention to an apparently submissive dog first or punishing the ‘bully’. Dogs do not expect equality or democracy creating unnatural conflict. 

 

Fear (and pain induced) aggression. 

Fear aggression is the opposite to dominance related aggression induced entirely by fear of the unknown, unpleasant experience or pain. In a behavioural sense, dominance is described as offensive whereas fear defensive (initially). Fear aggression is primarily learned behaviour. It is prevalent within dogs not properly socialised either with the environment with all of the different sights, smells and noises, or other dogs. Normality of the outside world may be unusual for the dog, and self preservation is a natural reaction to fear for any species. Therefore, fear aggression is the most common form of aggression in domestic dogs, created by a mixture of physical, physiological and emotional response to stimuli. Although an aggressive response may develop at any age, usually the origins can be traced back to and event or series of events occurring between the age of 7 to 12 weeks of age. Equally, a fearful response may be inherited genetically; offspring can have a genetic potential pre wired to be submissive and fearful with an inherited reactivity to stimulus. Behaviour can also be reinforced by learnt response, for example a fearful dog snapping and showing aggressive communication toward another dog, which responds by fleeing or backing off. Reward therefore for the fearful aggressive display. The dog showing aggression related to fear may be difficult to recognise, given that the body language and posture is very similar to any aggressive response; a mix of subservient and aggression, the ears back, tail low perhaps with a short quick wag, back may be arched, head low with the usual bearing of teeth and heckles raised. Equally, through learned experience, the fearful aggressive dog may appear dominant to remove the threat and getting in first by use of attack. This dog has learned by acting in a dominant way he may assert himself before another has the opportunity to gain any advantage. Restriction is another major factor creating fear and aggression. Again, perhaps as a result of poor socialisation and habituation, a dog without the opportunity of a flight response; on a lead, in the car or without sufficient space, can easily develop a fearful aggressive response. 

 

Protective and territorial (including maternal) aggression. 

The above forms of aggression occur when the dog is in protective state over what he or she perceives to be theirs. Biting the postman, fighting over toys and chasing cars may be manifestations of protective aggression. This can be stimulated by both dominance and fear, and again, not easily segregated between the two. Both males and females are prone to protective aggression, and is a natural response for canines. Dominance related is slightly more prominent in males, and for females in extreme cases, may be linked to maternal protection. Phantom pregnancies are known to stimulate emotions related to protective behaviour. 

 

Inter male aggression. 

Males of many (and all domesticated) species have a proclivity for fighting each other. Rare in females, when occurring this is a specific form of dominance aggression, when conflict occurs and may only be resolved through confrontation. Inter male aggression however is not wholly dependent on the male hormone testosterone but only occurs after puberty, originating during the neonatal development of the pup and stimulated by early masculinisation just before birth. The testosterone surge at puberty is the underlying cause of such aggression but is only influential on the already maculated brain. Stimulated by sight or scent of another dog prevention and treatment may be a difficult process.  

 

Predatory aggression. 

All dogs have an innate predisposition to prey upon other animals. To hunt is both genetic and learned from mother. The predation sequence is instinctual, a desire to chase grab and kill what is thought to be prey such as a small animal. This has been diluted within many breeds of domestic dogs, strong in others, but never completely eliminated. For example; the herding breeds have a strong desire for the chase but may not carry out the bite – hold – kill process in the same way as a Terrier. The predatory sequence is not based on hunger, but the strong instinct begins with movement of something resembling potential prey, such as another dog perhaps of a smaller stature. Predatory aggression is used as a term for a dog displaying the usual behavioural characteristics of the predation sequence; beginning with a stare, silent careful and quick movement toward prey with a grab bite to a vital organ such as the jugular. Very much impulsive. Although many owners are aware of the potential for their dog to chase squirrels and cats for example, predatory behaviour toward another dog may be shocking for them and difficult to understand. 

 

Learned aggression. 

Although a component most of the above described forms of aggression may be partly, if not wholly, learned; this is a specific aggression where a dog is taught to fight with another. Generally relating to breeds such as the bull breeds which are pit against one another for sport and competition. Often pain induced involving most forms of dominance and protective aggression which is enhanced and redirected by humans. Unfortunately, such breeds historically involved arguably still possess a genetic predisposition for such aggression.