Fears and phobias in humans, such as those to heights, bugs, snakes and so on, are not uncommon. Likewise, dogs can experience fears and phobias too. To some degree, this behavior is normal and to be expected, but not when it's in the extreme.

For dogs, fear responses can manifest in a variety of behaviors, such as panting, shaking, hiding, rolling over and urinating, defecating, running away with the tail between the legs, and exhibiting submissive body postures like holding the ears back and down or focusing the eyes downward and away. In the extreme, or if cornered, aggressive behavior may occur. Chronic or long-term fear or anxiety can also cause physical disturbances like diarrhea, loss of appetite, self-trauma, vomiting, and weight loss.

Separation anxiety is a type of anticipatory fear of the future that can be seen in some anxious dogs. A dog with separation anxiety will exhibit distress when his owner leaves that is out of proportion with the events that lead up to his owner's absence and, immediately after the owner leaves, he may start barking, whining, chewing, soiling or so on. While this behavior may be considered abnormal, it is not considered a phobia.

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