Although it is possible for a fearful dog to be frightened of his owners, this is rarely the case. Fearfulness is usually expressed toward strangers, toward unfamiliar people outside the family circle who are not frequent visitors to the household.

Sometimes a dog that is frightened of people may have his targets fairly well defined. For example, his fear may be of men with white beards or men wearing boots. In other instances, dogs may respond to several different categories of fear-inducing people, men of large stature, men with deep voices, etc. Note that it is men rather than women who are most often the subjects of dogs fearfulness.

Children are also common sources of fear for dogs, too, particularly male children. Then again, some dogs are frightened of all strangers, whatever their age, sex, height, weight, or other physical characteristics. These dogs are pathetic creatures that have, no doubt, experienced a lifetime of mistreatment.

Responses to Fear

One of the most common responses of the fearful dog is aggression. Other responses are more passive, including those of avoidance, hiding, running away, and thigmotaxic behavior (staying close to the wall). Fearful dogs display their emotions by means of their facial expression and body postures, as well as exhibiting various involuntary responses, such as trembling, salivating, pupillary dilatation, evacuation of bowels or bladder, and discharge of anal glands. Dogs that are frightened of people avert their eyes, lower their head, flatten their ears, tuck their body and tail (hunkering down to make themselves smaller), and may roll over to expose their underbelly and urinate. All this body language is designed to appease the would-be attacker by signaling a diminutive status.

How Dogs Become Fearful

Like everything else, nature and nurture both play a role in the development of fears. Some dogs seem naturally fearful of people. Dogs that show familial nervousness may have hormonal disturbances, such as sub-clinical hypothyroidism (a condition in which the thyroid gland is under producing the hormone, thyroxine) but for many the true cause of their genetic fearfulness remains unknown.

Learning provides the other component necessary for the development of fear. Lack of appropriate exposure and/or adverse exposures during the sensitive period of development favors the development of fear. For example, a dog that is overly fearful of people may not have been exposed to people during the sensitive period of his development, i.e. between 3 and 12 weeks of age. If during this time a dog is raised without human company he may never be entirely comfortable in the presence of unfamiliar people. While not necessarily hostile to strangers, the dog may appear fearful in their presence and may attempt to avoid them or hide.

Truly adverse experiences at the hands of cruel people during the sensitive period is worse than plain undersocialization. Such heinous experiences lead to the more specific fears alluded to above i.e. fear of men with white beards, tall hats, etc. Men and children, it seems, are most likely to behave inappropriately towards dogs during the sensitive period of development (and beyond) and thus are most often the subjects of dogs' fearfulness and mistrust. While nature and nurture can be considered separately for their input into excessively fearfulness, both components are necessary for its expression.