Most common reason for aggression to strangers in UK.
Frequently occurs at boundaries and thresholds - in cars, next to owner, if restricted, if dog cornered and cannot retreat.
Common in more sensitive and nervous breeds.
Aggression may be unpredictable - usually associated with low level of aggression which is rarely triggered.This is a function of knowledge and a good clinician will identify the class of stressors to which dog reacts and to which a probablistic assessment can be assigned.
May also:
Occur during periods of stress or disease.
Be predictable - whenever known stimuli present.
Response is normally dependent upon salience of stimulus and is influenced by previous learning.
Presenting signs
Aggression may seem overt as little or no signs of fear seen if there have been a lot of reinforcement opportunities.
Bites rear of stranger, eg ankles, back of legs or arms, often as they turn to leave.
Bites hand(s) of stranger, especially when they attempt to touch the animal.
Bites owner (usually the hands) whom it fears.
Snaps, vocal warning tries to avoid and only aggressive if flight not possible.
Acute presentation
Owner requests euthanasia after aggressive incident, usually involving a child, or authorities, eg police.
Owner's attitude depends on: own tolerance, severity of problem, how long they lived with dog of problem.
Age predisposition
Can begin in puppyhood, or later with experience.
Old age due to senses giving less warning of person approaching.
Sex predisposition
Thought to be more common in males.
Breed predisposition
German Shepherd dog .
Collies, particularly Border Collie .
Terriers, particularly Jack Russell Terrier.
Guarding breeds, eg Dobermann , Rottweiler .
Cost considerations
Owners found guilty of an offence under the various Acts may be liable to a fine, damages and legal costs.
Owners should be made aware of their responsibilities for keeping others safe.
Owners should be given advice to enable them to prevent further aggression, eg physical restriction using collar/lead/head collar. May make dog worse.
For mild cases and shyness/snapping in puppies, the following advice is appropriate:
Protect dog from any experience likely to cause further aggression, panic or fear.
Allow controlled exposure to strangers using a technique known as systematic desensitization. Allow the dog to approach the stranger, rather than the stranger approaching the dog (advice MUST be given to allow protection of the stranger from aggression).
Use activities enjoyed by the dog to accelerate this process, eg eating, playing, walking.
Remove any reinforcers of fear, eg punishment of behavior by owner. In absence of specialist knowledge consider referral.
May make dog worse.
In absence of specialist knowledge consider referral.