Fear aggression is triggered by a stimulus that appears threatening to the dog. It is sometimes referred to as defensive aggression
although there might be aspects of defensive aggression where the pet does not appear to be fearful. For example, aggression
in response to ear cleaning or physical punishment might be examples of defensive aggression where the fear component is minimal.
Fear aggression may be displayed when a dog is the recipient of assertive posturing or facial expressions, or approached by
another dog or person that is unfamiliar, unfriendly or in some way threatening to the dog. It usually occurs when the dog
is unable to avoid the stimulus that brings about a fear aggressive response.
Inadequate socialization, traumatic experiences, punishment and genetics can all contribute to the development of fear aggression..
Fear aggression may be aggravated when the owner responds with punishment or anxiety, when the stimulus (e.g. other dog) shows
fear or aggression or when the stimulus retreats (negative reinforcement).by talking softly to the dog in an attempt to reduce
its anxiety. It is also possible that the owner's attempts to settle the dog by offering a toy or treat may reinforce the
Genetics can play a role in determining the threshold for a fear response. There is considerable variation in the canine
population regarding the types of responses that are generated by fear-provoking stimuli. Some dogs require a very strong
stimulus to elicit fear, while others become extremely anxious in response to mild stimuli or any auditory or visual stimuli
that is only the least bit unusual.
A dog that has a low threshold for becoming fearful that encounters multiple, strong, fear-inducing stimuli with little chance
for escape has a high likelihood of biting, especially if biting has caused the stimulus to move away during past encounters.
Determinants of the probability of a bite from a fearful pet
Diagnosis and prognosis
Fear aggression is manifested by fearful facial expressions and body postures (tail down, ears rotated back, crouched body,
weight shifted away from the fear-eliciting stimulus) accompanied by aggressive signs such as piloerection, barking, growling,
snarling and biting. Dilated pupils, increased respiratory rate and a rapid heart rate generally accompany an overwhelming
fear response. The pet might also defecate or urinate if it is exceptionally fearful.
Factors suggesting a good prognosis include
• The duration of the problem is short
• The fearful behavior was acquired as an adult
• All fear-eliciting stimuli are well defined
• Fear-eliciting environmental stimuli can be controlled
• The pet has a relatively high threshold for responding to fear stimuli
• The pet can be protected from strong stimulus exposure during treatment.
The prognosis for safe resolution of fear aggression is generally more favorable (particularly if all potential stimuli can
be identified) than for dominance-related aggression but adequate care must still be taken. The owners, as well as others,
are at risk handling a dog with fear aggression and must be counseled accordingly.